Arc extinguishing circuit and new energy automobile

Abstract

The utility model discloses an arc extinguishing circuit and a new energy automobile, the arc extinguishing circuit comprises a main positive contactor, a main negative contactor and a shunt arc extinguishing module, the input end of the main positive contactor is connected with the anode of a battery, and the output end of the main positive contactor is connected with the anode of a load; the input end of the main negative contactor is connected with a load cathode; the output end of the main negative contactor is connected with a battery cathode; the shunting arc extinguishing module is connected with the main positive contactor in parallel, the shunting arc extinguishing module comprises a pre-charging module and a shunting module, and the pre-charging module and the shunting module are used for conducting when the main positive contactor is disconnected and shunting current flowing through the main positive contactor. By arranging the pre-charging module and the shunting module which play an arc extinguishing role, the pre-charging module and the shunting module are simultaneously conducted when the main positive contactor is disconnected, so that the current flowing through the main positive contactor is greatly reduced, the energy intensity of the arc is lower, the arc can be extinguished more quickly, and the disconnection efficiency of the contactor is higher.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to an arc extinguishing circuit and a new energy vehicle. Background Art

[0002] The BDU (Battery Energy Distribution Unit) within new energy vehicles is a core component that controls battery power distribution and protects the battery pack. The BDU is composed of multiple independent components connected by copper busbars and wiring harnesses. Key components include the main positive contactor, main negative contactor, pre-charge contactor, pre-charge resistor, and fuses. The proper functioning of the main positive and negative contactors determines the proper charging and discharging of the battery pack. New energy vehicle platforms utilize high-voltage systems. Directly switching contactors can generate arcs, which can cause contact erosion or adhesion, leading to contactor damage.

[0003] In existing technology, arc extinguishing circuits in battery energy distribution units are typically implemented using a pre-charging circuit. This circuit pre-charges the contactor when it's normally closed, reducing the voltage differential across the contactor and significantly minimizing arcing when closed. However, in abnormal conditions, such as short circuits or overcurrent, disconnection fails to protect the contactor, leading to contact sticking. Utility Model Content

[0004] The embodiments of the present utility model provide an arc extinguishing circuit and a new energy vehicle to solve the problem that the existing arc extinguishing circuit has poor arc extinguishing effect and easily causes the main positive contactor contacts in the main circuit to stick together, resulting in the contactor being unable to disconnect.

[0005] Based on the above objectives, in a first aspect, an arc extinguishing circuit is provided, the arc extinguishing circuit comprising:

[0006] A main positive contactor, a main negative contactor and a shunt arc extinguishing module, wherein the input end of the main positive contactor is used to connect to the positive pole of the battery, and the output end of the main positive contactor is used to connect to the positive pole of the load; the input end of the main negative contactor is used to connect to the negative pole of the load, and the output end of the main negative contactor is used to connect to the negative pole of the battery;

[0007] The shunt arc extinguishing module is connected in parallel with the main positive contactor. The shunt arc extinguishing module includes a pre-charging module and a shunt module. The pre-charging module and the shunt module are used to conduct and shunt the current flowing through the main positive contactor when the main positive contactor is disconnected.

[0008] Optionally, the pre-charge module includes a switch and a pre-charge resistor, and the switch is connected in series with the pre-charge resistor.

[0009] Optionally, the shunt module is connected in parallel with the pre-charging resistor.

[0010] Optionally, the shunt module includes at least one PTC resistor.

[0011] Optionally, the shunt module includes a first heater module and a second heater module, the first heater module and the second heater module are connected in series, at least one PTC resistor is provided in the first heater module, and at least one PTC resistor is provided in the second heater module.

[0012] Optionally, the resistance range of the pre-charging resistor is 5Ω-20Ω, and the resistance range of the PTC resistor in a cold state is 10mΩ-10Ω.

[0013] Optionally, the first heater module includes two or more PTC resistors connected in parallel.

[0014] Optionally, the second heater module includes two or more PTC resistors connected in parallel.

[0015] Optionally, the switch is a mechanical switch, and the mechanical switch includes a relay or a contactor.

[0016] Optionally, the switch is a semiconductor switch, and the semiconductor switch includes a MOS tube or an IGBT tube.

[0017] Based on the above purpose, in a second aspect, a new energy vehicle is provided, comprising a power battery and a battery energy distribution unit built into the vehicle body, wherein the battery energy distribution unit comprises the arc extinguishing circuit described in the first aspect.

[0018] The above-mentioned arc extinguishing circuit and new energy vehicle, by setting two pre-charging modules and shunt modules for arc extinguishing in the shunt arc extinguishing module, make the pre-charging module and the shunt module be turned on at the same time when the main positive contactor is disconnected, further reducing the total equivalent resistance of the branch, so that the two branches of the pre-charging module and the shunt module can share more current, which correspondingly reduces the current of the main circuit where the main positive contactor is located, increases the resistance, lowers the energy intensity of the arc, can extinguish the arc faster, and has a higher disconnection efficiency of the contactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0020] Figure 1 This is a circuit diagram of a first arc extinguishing circuit in an embodiment of the present utility model;

[0021] Figure 2This is a circuit diagram of a second arc extinguishing circuit in an embodiment of the present utility model;

[0022] Figure 3 This is a circuit diagram of a third arc extinguishing circuit in an embodiment of the present utility model;

[0023] Figure 4 This is a graph showing the volt-ampere characteristic of an arc in one embodiment of the present invention;

[0024] Figure 5 This is a graph showing the relationship between the resistance value and temperature of a PTC resistor in one embodiment of the present invention. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0026] It should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to make the disclosure thorough and complete and to fully convey the scope of the present invention to those skilled in the art. In the drawings, the dimensions and relative dimensions of layers and regions may be exaggerated for clarity. Like reference numerals denote like elements throughout.

[0027] It should be understood that when an element or layer is referred to as being "on," "adjacent to," "connected to," or "coupled to" another element or layer, it may be directly on, adjacent to, connected to, or coupled to the other element or layer, or there may be intervening elements or layers. Conversely, when an element is referred to as being "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" another element or layer, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers, and / or parts, these elements, components, regions, layers, and / or parts should not be limited by these terms. These terms are merely used to distinguish one element, component, region, layer, or part from another element, component, region, layer, or part. Therefore, without departing from the teachings of the present invention, the first element, component, region, layer, or part discussed below may be represented as a second element, component, region, layer, or part.

[0028] Spatially relative terms such as "under," "beneath," "below," "under," "above," "above," etc., may be used herein for convenience of description to describe the relationship of one element or feature shown in the figures to other elements or features. It should be understood that the spatially relative terms are intended to include different orientations of the device in use and operation in addition to the orientations shown in the figures. For example, if the device in the drawings is flipped, then the elements or features described as "under" or "beneath" or "beneath" the other elements will be oriented as "over" the other elements or features. Thus, the exemplary terms "under" and "under" may include both the upper and lower orientations. The device may be oriented otherwise (rotated 90 degrees or in other orientations) and the spatial descriptors used herein are interpreted accordingly.

[0029] The purpose of the terms used herein is only to describe specific embodiments and is not intended to limit the present invention. When used herein, the singular forms "a", "an" and "the" are also intended to include the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "comprising" and / or "including", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0030] In order to fully understand the present invention, the following description will provide detailed structures and steps to illustrate the technical solutions proposed by the present invention. The preferred embodiments of the present invention are described in detail below. However, in addition to these detailed descriptions, the present invention may also have other implementation methods.

[0031] In one embodiment, if Figure 1 As shown, an arc extinguishing circuit is provided, the arc extinguishing circuit comprising:

[0032] A main positive contactor, a main negative contactor and a shunt arc extinguishing module, wherein the input end of the main positive contactor is used to connect to the positive pole of the battery, and the output end of the main positive contactor is used to connect to the positive pole of the load; the input end of the main negative contactor is used to connect to the negative pole of the load, and the output end of the main negative contactor is used to connect to the negative pole of the battery;

[0033] The shunt arc extinguishing module is connected in parallel with the main positive contactor. The shunt arc extinguishing module includes a pre-charging module and a shunt module. The pre-charging module and the shunt module are used to conduct and shunt the current flowing through the main positive contactor when the main positive contactor is disconnected.

[0034] The working principle of the arc extinguishing circuit is:

[0035] Before closing the main positive contactor, the pre-charge module is turned on. This pre-charge increases the voltage across the main positive contactor, significantly reducing the energy of the generated arc and providing a pre-charge effect. When the main positive contactor is opened, the pre-charge module and the shunt module of the shunt arc extinguishing module are simultaneously controlled to conduct, allowing the pre-charge module and the shunt module to simultaneously shunt the current on the main positive contactor.

[0036] The arc extinguishing circuit of this embodiment is aimed at the arc extinguishing process when the main positive contactor is disconnected. When the main positive contactor is disconnected under high voltage and high current conditions or abnormal conditions, two pre-charging modules and shunt modules that play an arc extinguishing role are set in the shunt arc extinguishing module to further reduce the total resistance of the branch, so that the two branches can share more current. Correspondingly, the current of the main circuit is small and the resistance of the main circuit becomes larger. Since the arc energy is inversely proportional to the resistance, the arc energy of the main circuit will become smaller, which meets the arc initiation and arc extinguishing requirements under high voltage and high current or abnormal conditions, shortens the arc extinguishing time, and speeds up the arc extinguishing speed.

[0037] In one embodiment, if Figure 1 As shown, the pre-charge module includes a switch and a pre-charge resistor, and the switch is connected in series with the pre-charge resistor.

[0038] This application considers that when disconnecting the contactor under abnormal conditions, an arc will continuously erode the contact, potentially damaging the contact and rendering the contactor inoperable. The arc has a negative resistive characteristic, with intensity inversely proportional to resistance. The greater the arc energy intensity, the lower the corresponding resistance. Increasing the arc resistance reduces the arc energy intensity, and reducing it to zero effectively extinguishes the arc.

[0039] like Figure 4 The arc's volt-ampere characteristic curve shown in Figure 1 shows a DC arc with two stable burning points, Point A and Point B. At these points, di / dt = 0. To extinguish the arc, the stable burning points must be eliminated, and di / dt < 0. Therefore, arc extinguishing can be achieved by changing the slope of the line so that the arc's volt-ampere characteristic curve does not intersect the line. This means connecting a resistor in parallel at both ends of the arc to change the arc's resistance.

[0040] In this embodiment, the resistance value of the pre-charging resistor is set to be fixed, and the current flowing through the branch where the pre-charging module is located is fixed. When the contactor is disconnected under abnormal conditions, the current in the main circuit (i.e., the circuit where the main contactor is located) is too large. At this time, the pre-charging module is opened for shunting, the current in the main circuit will decrease, and the resistance of the corresponding main circuit will increase. According to the above content, it can be seen that the greater the resistance, the smaller the energy intensity of the arc, and the arc initiation and arc extinguishing operations can be completed by parallel pre-charging modules. For example, assuming that the resistance value of the pre-charging resistor is 20Ω, the battery voltage is 400V, and the branch current is 20A, the arc can be extinguished when the current drops to 20A under abnormal conditions, without waiting until the current is reduced to 0A.

[0041] The arc extinguishing circuit of this embodiment controls the switch to be closed, so that the pre-charging module and the shunt module are turned on at the same time, so that the pre-charging module and the shunt module together shunt the current on the main positive contactor, thereby achieving a rapid arc extinguishing effect.

[0042] In one embodiment, if Figure 1 As shown, the shunt module is connected in parallel with the pre-charging resistor.

[0043] Considering that if the battery output voltage is very high, the corresponding abnormal current will also be particularly large under abnormal conditions, assuming that the resistance of the pre-charge resistor remains unchanged and the battery voltage is increased to 1500V, the branch current can be 75A. At this time, the arc striking and arc extinguishing effect of the pre-charge resistor connected in parallel with the main positive contactor is greatly weakened, and the contacts will be damaged by arc erosion for a long time. However, the contactor structure cannot be modified to improve the arc extinguishing effect. First, as the voltage increases, the number of arc extinguishing grid layers must increase. However, the range of the permanent magnet arc blowing is limited. Even if the opening angle of the arc striking plate is increased, the arc blowing range cannot be expanded. If the structure is to meet the arc extinguishing effect, the corresponding contactor will be very large and the cost will be higher.

[0044] Therefore, in order to save costs, while keeping the existing structure of the contactor unchanged, the arc problem of disconnecting the contactor when high voltage is abnormal is solved by connecting a shunt module in parallel at both ends of the pre-charge resistor, so as to achieve the effect of rapid arc extinguishing.

[0045] In one embodiment, the shunt module includes at least one PTC resistor.

[0046] like Figure 2 As shown in the figure, after the PTC resistor is connected in parallel at both ends of the pre-charging resistor R, the overall resistance of the shunt arc extinguishing module is reduced, the current divided by the branch of the shunt arc extinguishing module is increased, the current of the main circuit (the circuit where the main positive contactor K1 is located) is smaller, the resistance is smaller, and the energy intensity of the arc is lower, that is, the contacts can extinguish the arc faster.

[0047] For example, assuming that after the PTC resistor is connected in parallel, the overall resistance value of the shunt arc extinguishing module is 5Ω. The same voltage value of 1500V corresponds to a branch current of 300A. Then, under abnormal conditions, the arc can be completely extinguished when the current drops to 300A, which is earlier than when the PTC resistor is not connected in parallel. This can prevent the contacts from being burned by the arc for a longer time, thereby improving the safety and reliability of the contactor.

[0048] like Figure 5The curve showing the relationship between the resistance and temperature of the PTC resistor shows that the shunt module must be opened and arc extinguished within the PTC resistor's cold state (e.g., room temperature). Within this range, the PTC resistor's resistance is very low and barely changes with temperature, allowing for effective arc extinguishing. Otherwise, prolonged high current flow will cause the PTC resistor to heat up, increasing its internal resistance and rendering arc extinguishing ineffective. Furthermore, the arc extinguishing circuit of this embodiment is suitable for both disconnecting the contactor to extinguish the arc under abnormal circumstances and opening it during the final short period of arc extinguishing during normal disconnection to achieve premature arc extinguishing.

[0049] The arc-extinguishing circuit of this embodiment initiates the arc by connecting a PTC resistor in parallel across the pre-charge resistor. This reduces the current flowing through the main circuit, allowing the arc to be quickly extinguished when the main positive contactor is disconnected, thereby improving contactor reliability. This method not only meets the requirement for rapid arc extinguishing when the contactor is disconnected at high voltages of several hundred or several thousand volts, but also requires no modifications to the existing structure, resulting in low cost.

[0050] In one embodiment, if Figure 3 As shown, the shunt module includes a first heater module 31 and a second heater module 32 , the first heater module 31 and the second heater module 32 are connected in series, at least one PTC resistor is set in the first heater module 31 , and at least one PTC resistor is set in the second heater module 32 .

[0051] In this embodiment, the specific number and connection method of the PTC resistors are determined by parameters such as the actual voltage, the pre-charge resistor value, the main circuit current value, and the expected disconnection time.

[0052] In one embodiment, the first heater module includes two or more PTC resistors connected in parallel.

[0053] like Figure 3 As shown, the first heater module 31 may include three PTC resistors connected in parallel with each other; as other embodiments, the number of PTC resistors connected in parallel in the first heater module 31 may also be two, four, or more than four.

[0054] In one embodiment, the second heater module includes two or more PTC resistors connected in parallel.

[0055] like Figure 3 As shown, the second heater module 32 may include three PTC resistors connected in parallel with each other; as other embodiments, the number of PTC resistors connected in parallel in the first heater module 32 may also be two, four, or more than four.

[0056] In one embodiment, the switch is a mechanical switch, and the mechanical switch includes a relay or a contactor.

[0057] As another embodiment, in order to achieve reliable conduction and disconnection of the shunt arc extinguishing module, two mechanical switches can also be set, one of which is connected in series with the pre-charge resistor, and the other is connected in series with the shunt module. By controlling the on and off of the two mechanical switches respectively, the pre-charge module and the shunt module can be controlled separately.

[0058] In one embodiment, the switch is a semiconductor switch, and the semiconductor switch includes a MOS transistor or an IGBT transistor. As another embodiment, the semiconductor switch may also be a triode or the like.

[0059] As another embodiment, in order to achieve reliable conduction and disconnection of the shunt arc extinguishing module, two semiconductor switches can also be set, one of which is connected in series with the pre-charge resistor, and the other is connected in series with the shunt module. By controlling the on and off of the two semiconductor switches respectively, the pre-charge module and the shunt module can be controlled separately.

[0060] In one embodiment, a new energy vehicle is provided, comprising a power battery and a battery energy distribution unit built into the vehicle body, wherein the battery energy distribution unit comprises a fuse and the arc extinguishing circuit described in any of the previous embodiments, wherein the fuse is connected in series with a main contactor.

[0061] The new energy vehicle of this embodiment is provided with an arc extinguishing circuit in the battery energy distribution unit. The arc extinguishing circuit has a built-in shunt arc extinguishing module with two pre-charging modules and a shunt module for extinguishing the arc. When the main positive contactor is disconnected, the pre-charging module and the shunt module are turned on at the same time, which greatly reduces the current flowing through the main positive contactor. The energy intensity of the arc is lower, the arc can be extinguished faster, and the disconnection efficiency of the contactor is higher.

[0062] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention, and should all be included in the scope of protection of the present invention.

Claims

1. An arc extinguishing circuit, characterized in that: The arc extinguishing circuit comprises: A main positive contactor, a main negative contactor and a shunt arc extinguishing module, wherein the input end of the main positive contactor is used to connect to the positive pole of the battery, and the output end of the main positive contactor is used to connect to the positive pole of the load; the input end of the main negative contactor is used to connect to the negative pole of the load, and the output end of the main negative contactor is used to connect to the negative pole of the battery; The shunt arc extinguishing module is connected in parallel with the main positive contactor. The shunt arc extinguishing module includes a pre-charging module and a shunt module. The pre-charging module and the shunt module are used to conduct and shunt the current flowing through the main positive contactor when the main positive contactor is disconnected.

2. The arc extinguishing circuit according to claim 1, characterized in that: The pre-charge module includes a switch and a pre-charge resistor, and the switch is connected in series with the pre-charge resistor.

3. The arc extinguishing circuit according to claim 2, characterized in that: The shunt module is connected in parallel with the pre-charging resistor.

4. The arc extinguishing circuit according to claim 3, characterized in that: The shunt module includes at least one PTC resistor.

5. The arc extinguishing circuit according to claim 4, characterized in that: The resistance range of the pre-charging resistor is 5Ω-20Ω, and the resistance range of the PTC resistor in a cold state is 10mΩ-10Ω.

6. The arc extinguishing circuit according to claim 4, characterized in that: The shunt module includes a first heater module and a second heater module. The first heater module and the second heater module are connected in series. At least one PTC resistor is provided in the first heater module, and at least one PTC resistor is provided in the second heater module.

7. The arc extinguishing circuit according to claim 6, characterized in that: The first heater module includes two or more PTC resistors connected in parallel.

8. The arc extinguishing circuit according to claim 6, characterized in that: The second heater module includes two or more PTC resistors connected in parallel.

9. The arc extinguishing circuit according to any one of claims 2 to 8, characterized in that: The switch is a mechanical switch, and the mechanical switch includes a relay or a contactor.

10. A new energy vehicle, characterized in that: It comprises a power battery and a battery energy distribution unit built into the vehicle body, and the battery energy distribution unit comprises the arc extinguishing circuit according to any one of claims 1 to 9.

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