High-voltage circuit short-circuit protection methods

Abstract

This invention discloses a high-voltage circuit short-circuit protection method. The method includes: a battery management system (BMS) acquiring the high-voltage current of the high-voltage circuit corresponding to the battery energy distribution unit; the BMS determining the high-voltage circuit state based on the high-voltage current; and the BMS controlling the battery energy distribution unit to disconnect power based on the high-voltage circuit state and the high-voltage current. In this solution, the BMS can determine whether the high-voltage circuit is short-circuited by the high-voltage circuit state. When the short-circuit current cannot cause the integrated active-passive fuse to quickly thermally accumulate and disconnect the high-voltage circuit, the BMS controls the integrated active-passive fuse to actively disconnect the high-voltage circuit. When the short-circuit current can cause the integrated active-passive fuse to quickly thermally accumulate and disconnect the high-voltage circuit, the integrated active-passive fuse passively disconnects the high-voltage circuit through the thermal accumulation effect. Therefore, fast and effective short-circuit protection across the entire current range is achieved for the high-voltage circuit.

Description

Technical Field

[0001] This invention relates to the field of electric vehicle safety protection technology, and in particular to a method for short-circuit protection of high-voltage circuits. Background Technology

[0002] Currently, the high-voltage circuit of the battery energy distribution unit of electric vehicles on the market is generally composed of fuses, high-voltage relays, and current sensors.

[0003] Specifically, if a passive fuse is used, when an abnormal current occurs in the high-voltage circuit, the high-voltage circuit is cut off by the current heat accumulation effect of the passive fuse. The time-current withstand curve of the passive fuse intersects with the time-current withstand curve of the high-voltage relay at a point. Before this intersection, the high-voltage relay is responsible for protecting the high-voltage circuit; after the intersection, the passive fuse is responsible for protecting the high-voltage circuit. However, there is a protection blind zone before the intersection and after the relay's ultimate breaking capacity. In this protection blind zone, the current flowing through the relay exceeds the relay's ultimate breaking capacity, and the relay cannot cut off the circuit. At this time, the passive fuse withstands this current for a longer period, and its cutting time is also longer. Therefore, the passive fuse cannot quickly and effectively cut off the high-voltage circuit, which can lead to damage to some components in the high-voltage circuit due to the prolonged flow of large current, thus failing to provide effective full-current range protection for the high-voltage circuit.

[0004] If an active fuse is used, when an abnormal current occurs in the high-voltage circuit, the active fuse receives an external disconnect signal and actively disconnects the circuit. The active fuse then ignites explosives based on the disconnect signal, triggering the active fuse to disconnect the high-voltage circuit. However, when the current in the high-voltage circuit (e.g., above 6000A or even 10000A) is too large, the active fuse needs to go through a series of processes to disconnect the high-voltage circuit. These processes typically take tens of milliseconds. During this time, the components in the high-voltage circuit will be damaged within tens of milliseconds of the excessive current flowing through them. Clearly, an active fuse cannot provide effective full-current-range short-circuit protection for the high-voltage circuit. Summary of the Invention

[0005] This invention provides a method for short-circuit protection of high-voltage circuits, enabling fast and effective short-circuit protection across the entire current range for high-voltage circuits.

[0006] This invention provides a high-voltage circuit short-circuit protection method. The high-voltage circuit short-circuit protection system includes a battery management system and a battery energy distribution unit; the battery energy distribution unit includes an integrated active and passive fuse; the battery management system is connected to the integrated active and passive fuse.

[0007] The high-voltage circuit short-circuit protection method includes:

[0008] The battery management system obtains the high-voltage current of the high-voltage circuit corresponding to the battery energy distribution unit;

[0009] The battery management system determines the state of the high-voltage circuit based on the high-voltage current.

[0010] The battery management system controls the active-passive integrated fuse to disconnect the high-voltage circuit based on the high-voltage circuit status and the high-voltage current.

[0011] Optionally, the battery energy distribution unit includes a current sensor, which is connected to the battery management system;

[0012] Before the battery management system obtains the high-voltage current from the high-voltage circuit corresponding to the battery energy distribution unit, it includes:

[0013] The current sensor detects the high-voltage current in the high-voltage circuit;

[0014] The current sensor sends the high-voltage current to the battery management system.

[0015] Optionally, the battery management system determines the high-voltage circuit state based on the high-voltage current, including:

[0016] The battery management system calculates the duration for which it receives the high-voltage current;

[0017] The battery management system obtains the state of the high-voltage circuit based on the high-voltage current and the duration.

[0018] Optionally, the high-voltage circuit state includes a short-circuit state and a non-short-circuit state;

[0019] The battery management system obtains the high-voltage circuit state based on the high-voltage current and the duration, including:

[0020] The battery management system determines whether the high-voltage current is greater than a first preset current.

[0021] If not, then the high-voltage circuit state is the non-short-circuit state;

[0022] If so, the battery management system determines whether the duration is greater than a preset time;

[0023] If so, then the high-voltage circuit state is the short-circuit state;

[0024] If not, then the high-voltage circuit state is the non-short-circuit state.

[0025] Optionally, the first preset current is greater than the maximum overload current of the battery energy distribution unit, and the first preset current is less than or equal to the maximum withstand current of any relay in the high voltage circuit.

[0026] The preset time is less than the maximum withstand time of any relay in the high-voltage circuit, and the preset time is greater than the maximum overload withstand time of the battery energy distribution unit.

[0027] Optionally, the battery management system controls the integrated active-passive fuse to disconnect the high-voltage circuit based on the high-voltage circuit status and the high-voltage current, including:

[0028] If the high-voltage circuit is in a short-circuit state, the battery management system determines whether the high-voltage current is less than or equal to the second preset current.

[0029] If so, the battery management system sends a cut-off signal to the active-passive integrated fuse, so that the active-passive integrated fuse actively disconnects the high-voltage circuit according to the cut-off signal;

[0030] If not, the active-passive integrated fuse passively disconnects the high-voltage circuit.

[0031] Optionally, the second preset current is the withstand current corresponding to the intersection of the withstand current curve of the integrated active-passive fuse and the withstand current curve of the relay in the high-voltage circuit.

[0032] Optionally, after the battery management system controls the integrated active-passive fuse to disconnect the high-voltage circuit, the system further includes:

[0033] The battery management system detects the voltage difference between the positive and negative terminals of the battery energy distribution unit;

[0034] The battery management system determines the high-voltage circuit conduction state of the battery energy distribution unit based on the positive and negative voltage difference.

[0035] The battery management system controls the relay of the battery energy distribution unit to disconnect according to the conduction state of the high-voltage circuit.

[0036] Optionally, the battery management system determines the high-voltage circuit conduction state of the battery energy distribution unit based on the positive and negative electrode voltage difference, including:

[0037] The battery management system determines whether the voltage difference between the positive and negative electrodes is less than or equal to a threshold voltage.

[0038] If so, the high-voltage circuit is in an open state.

[0039] If not, then the high-voltage circuit is in the conducting state.

[0040] Optionally, the relays of the battery energy distribution unit include a main positive relay and a main negative relay;

[0041] The battery management system controls the relay of the battery energy distribution unit to disconnect according to the conduction state of the high-voltage circuit, including:

[0042] If the high-voltage circuit is in the open state, the battery management system controls the main positive relay and the main negative relay of the battery energy distribution unit to disconnect.

[0043] If the high-voltage circuit is in the on state, the battery management system controls the main negative relay of the battery energy distribution unit to disconnect, and controls the main positive relay to disconnect after the main negative relay is disconnected.

[0044] This invention utilizes a battery management system to acquire the high-voltage current of the high-voltage circuit corresponding to the battery energy distribution unit. This allows for real-time monitoring of the high-voltage current, facilitating subsequent analysis and judgment, and ultimately providing real-time protection for the high-voltage circuit. The battery management system determines whether a short circuit has occurred in the high-voltage circuit based on the high-voltage current, thus defining the high-voltage circuit status. The system can determine whether a short circuit has occurred by monitoring the high-voltage circuit status and whether the high-voltage current is sufficient to rapidly thermally accumulate and disconnect the high-voltage circuit using an integrated active-passive fuse. When the high-voltage circuit is short-circuited and the high-voltage current is insufficient to rapidly thermally accumulate and disconnect the high-voltage circuit using the integrated active-passive fuse, the system controls the integrated active-passive fuse to actively disconnect the high-voltage circuit. Conversely, when the short-circuit current is sufficient to rapidly thermally accumulate and disconnect the high-voltage circuit using the integrated active-passive fuse, the integrated active-passive fuse passively disconnects the high-voltage circuit through thermal accumulation. Attached Figure Description

[0045] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0046] Figure 1 A schematic diagram of a high-voltage circuit short-circuit protection system provided in an embodiment of the present invention;

[0047] Figure 2 A flowchart illustrating a high-voltage circuit short-circuit protection method provided in an embodiment of the present invention;

[0048] Figure 3 A time-current withstand curve of various components in a high-voltage circuit is provided for an embodiment of the present invention;

[0049] Figure 4 A flowchart illustrating another high-voltage circuit short-circuit protection method provided in an embodiment of the present invention;

[0050] Figure 5 A flowchart illustrating a method for determining the state of a high-voltage circuit in a battery management system, as provided in an embodiment of the present invention;

[0051] Figure 6 This is a flowchart illustrating a method for determining the state of a high-voltage circuit in a battery management system, as provided in an embodiment of the present invention.

[0052] Figure 7 A flowchart illustrating a method for a battery management system to control an integrated active and passive fuse to disconnect a high-voltage circuit, provided in an embodiment of the present invention;

[0053] Figure 8 A flowchart illustrating another high-voltage circuit short-circuit protection method provided in an embodiment of the present invention;

[0054] Figure 9 This is a flowchart illustrating a method for a battery management system to determine the conduction state of the high-voltage circuit of a battery energy distribution unit, as provided in an embodiment of the present invention. Detailed Implementation

[0055] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0056] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0057] This invention provides a high-voltage circuit short-circuit protection method. This embodiment is applicable to the short-circuit protection control of high-voltage circuits equipped with integrated active and passive fuses. This method can be executed by a high-voltage circuit short-circuit protection system, which can be implemented in hardware and / or software.

[0058] Specifically, the high-voltage circuit short-circuit protection system includes a battery management system and a battery energy distribution unit; the battery energy distribution unit includes an integrated active and passive fuse; the battery management system is connected to the integrated active and passive fuse.

[0059] The battery management system (BMS) monitors and controls the battery energy distribution unit. It collects information from the high-voltage circuit of the BMS and controls it accordingly. The BMS then distributes the battery's electrical energy efficiently to the load components of the electric vehicle. An integrated active / passive fuse is connected in series in the high-voltage circuit of the BMS to protect the components from damage due to overcurrent.

[0060] For example, Figure 1 A schematic diagram of a high-voltage circuit short-circuit protection system provided in an embodiment of the present invention is shown below. Figure 1 As shown, the battery energy control system includes a battery management system 220 and a battery energy distribution unit 230. The battery energy distribution unit 230 includes an integrated active / passive fuse Q, a discharge terminal A, a charging terminal C, a main positive relay M1, a main negative relay M2, a pre-charge relay M3, a fast-charge relay M4, and a current sensor P.

[0061] The battery management system 220 is connected to the battery energy distribution unit 230. Specifically, the battery management system 220 is connected to the integrated active-passive fuse Q, the main positive relay M1, the main negative relay M2, the pre-charge relay M3, the fast-charge relay M4, and the current sensor P. The battery management system 220 can provide an excitation power signal to the integrated active-passive fuse Q, triggering the built-in propellant of the fuse Q to actively detonate the high-voltage circuit of the battery energy distribution unit 230, thus disconnecting the high-voltage circuit. Alternatively, the integrated active-passive fuse Q can also passively disconnect the high-voltage circuit through the current thermal accumulation effect. The battery management system 220 can send control signals to the main positive relay M1, the main negative relay M2, the pre-charge relay M3, and the fast-charge relay M4, thereby controlling the on / off states of these relays. The current sensor P detects the high-voltage current in the high-voltage circuit of the battery energy distribution unit 230, and can monitor the high-voltage current in the high-voltage circuit in real time and transmit the high-voltage current in the high-voltage circuit to the battery management system 220 in real time.

[0062] Figure 2 This is a flowchart illustrating a high-voltage circuit short-circuit protection method provided in an embodiment of the present invention, as shown below. Figure 2 As shown, this high-voltage circuit short-circuit protection method specifically includes the following steps:

[0063] S110, The battery management system obtains the high-voltage current of the high-voltage circuit corresponding to the battery energy distribution unit.

[0064] Here, high-voltage current refers to the current in the corresponding high-voltage circuit bus of the battery energy distribution unit. For details, please refer to [link / reference needed]. Figure 1 The battery energy distribution unit 220 includes a current sensor P, which is connected to the battery management system 220. The current sensor P can monitor the high-voltage current of the high-voltage circuit in real time. The battery management system 220 can obtain the high-voltage current through the current sensor P in real time, so as to facilitate subsequent analysis and judgment of the high-voltage current, and protect the high-voltage circuit in real time to prevent the high-voltage circuit fault from causing excessive high-voltage current and burning out the components connected to the high-voltage circuit.

[0065] S120 The battery management system determines the state of the high-voltage circuit based on the high-voltage current.

[0066] Specifically, the battery management system can analyze the high-voltage current to determine whether a short circuit has occurred in the high-voltage circuit. The high-voltage circuit state includes a short-circuit state and a non-short-circuit state. For example, if the high-voltage current exceeds the maximum current withstand capability of any connected device in the high-voltage circuit, a short circuit has occurred, and the high-voltage circuit state is short-circuit. In this case, the high-voltage circuit needs to be quickly and effectively disconnected to achieve rapid and effective short-circuit protection. Conversely, if the high-voltage current is less than the maximum current withstand capability of any connected device in the high-voltage circuit, the high-voltage circuit state is non-short-circuit.

[0067] S130 The battery management system controls the active and passive integrated fuse to disconnect the high-voltage circuit based on the high-voltage circuit status and high-voltage current.

[0068] Specifically, the battery management system can detect whether the high-voltage circuit is short-circuited by monitoring the high-voltage circuit status. The integrated active-passive fuse can actively disconnect the high-voltage circuit of the battery energy distribution unit by receiving the excitation power signal from the battery management system, and can also passively disconnect the high-voltage circuit through the current thermal accumulation effect. Thus, when a short circuit occurs in the high-voltage circuit, the battery management system can determine whether it is necessary to control the integrated active-passive fuse to actively disconnect the high-voltage circuit by monitoring the high-voltage current.

[0069] For example, Figure 3 This invention provides time-current withstand curves for various components in a high-voltage circuit. For example... Figure 3As shown, curve 310 is the time-current withstand curve of the battery that provides power to the high-voltage circuit, curve 320 is the time-current withstand curve of the relay in the high-voltage circuit, curve 330 is the time-current withstand curve of the safe temperature rise of each component in the high-voltage circuit, and curve 340 is the time-current withstand curve of the fuse in the active-passive integrated fuse. The time-current withstand curve of the fuse and the time-current withstand curve of the relay intersect at point 'a'. Before point 'a', there is a protection blind zone (e.g., intersection point b - intersection point a, where intersection point b can be the intersection of curves 330 and 320). In this protection blind zone, the withstand time of the fuse under the same current is greater than that of the relay. At this point, when the fuse passively disconnects the high-voltage circuit through the current thermal accumulation effect, the relay has already burned out, therefore the fuse cannot effectively protect the relay. Therefore, in the protection blind zone before the intersection of the fuse's time-current withstand curve and the relay's time-current withstand curve, the battery management system can provide an activation power signal to the integrated active-passive fuse, triggering its built-in propellant and actively breaking the high-voltage circuit of the battery energy distribution unit, thus effectively protecting the relay. After the intersection of the fuse's time-current withstand curve and the relay's time-current withstand curve, the fuse's withstand time is shorter than the relay's withstand time at the same current. At this point, the fuse can quickly and passively disconnect the high-voltage circuit through current thermal accumulation, and the shorter thermal accumulation time of the fuse compared to the relay's withstand time effectively protects the relay.

[0070] This invention provides an embodiment of the battery management system that acquires the high-voltage current of the high-voltage circuit corresponding to the battery energy distribution unit. This allows for real-time monitoring of the high-voltage current, facilitating subsequent analysis and judgment, and ultimately providing real-time protection for the high-voltage circuit. The battery management system determines whether a short circuit has occurred in the high-voltage circuit based on the high-voltage current, thus defining the high-voltage circuit status. The system can determine whether a short circuit has occurred by monitoring the high-voltage circuit status and whether the high-voltage current is sufficient to rapidly thermally accumulate and disconnect the high-voltage circuit using the integrated active-passive fuse. When the high-voltage circuit is short-circuited and the high-voltage current cannot rapidly thermally accumulate and disconnect the high-voltage circuit using the integrated active-passive fuse, the system controls the integrated active-passive fuse to actively disconnect the high-voltage circuit. Conversely, when the short-circuit current is sufficient to rapidly thermally accumulate and disconnect the high-voltage circuit using the integrated active-passive fuse, the fuse passively disconnects the high-voltage circuit through thermal accumulation.

[0071] Optional, continue to refer to Figure 1 The battery energy distribution unit 230 includes a current sensor P, which is connected to the battery management system 220.

[0072] Specifically, the current sensor P is a detection device that can detect current information and transform the detected current information into an electrical signal or other required form of information output that meets certain standards, according to a certain rule. The current sensor P detects the high-voltage circuit of the battery energy distribution unit 230, can monitor the high-voltage current of the high-voltage circuit in real time, and transmit the high-voltage current of the high-voltage circuit to the battery management system 220 in real time.

[0073] Figure 4 A flowchart illustrating another high-voltage circuit short-circuit protection method provided in an embodiment of the present invention is shown below. Figure 4 As shown, the method specifically includes the following steps:

[0074] S310, a current sensor, detects the high-voltage current in a high-voltage circuit.

[0075] The S320 current sensor sends high-voltage current to the battery management system.

[0076] S330, the battery management system obtains the high-voltage current of the high-voltage circuit corresponding to the battery energy distribution unit.

[0077] S340, the battery management system determines the state of the high-voltage circuit based on the high-voltage current.

[0078] The S350 battery management system controls the active and passive integrated fuse to disconnect the high-voltage circuit based on the high-voltage circuit status and high-voltage current.

[0079] In summary, the battery management system can detect and monitor the high-voltage current in the high-voltage circuit in real time through current sensors, thereby enabling real-time safety monitoring of the high-voltage circuit and, through analysis and judgment of the high-voltage current, providing real-time protection for the high-voltage circuit.

[0080] For example, Figure 5 This is a flowchart illustrating a method for determining the state of a high-voltage circuit using a battery management system, as provided in an embodiment of the present invention. Based on the above embodiment, the method for determining the state of a high-voltage circuit using a battery management system is further refined to include:

[0081] S410, the battery management system calculates the duration of the high-voltage current it receives.

[0082] Because high-voltage current can be unstable, the battery management system needs to calculate the duration of the high-voltage current it receives in order to prevent inaccurate high-voltage current readings due to fluctuations in the high-voltage current.

[0083] The S420 battery management system obtains the high-voltage circuit status based on the high-voltage current and duration.

[0084] Specifically, if the battery management system receives an excessively high-voltage current over a period of time, it indicates that the excessive high-voltage current is not caused by high-voltage current fluctuations, but rather by a fault in the high-voltage circuit. If the duration of the excessively high-voltage current received by the battery management system is short, it indicates that the excessive high-voltage current is caused by high-voltage current fluctuations. Therefore, the battery management system can determine the state of the high-voltage circuit based on the high-voltage current and its duration.

[0085] In summary, by calculating the duration of the high-voltage current received by the battery management system and determining the state of the high-voltage circuit based on the high-voltage current and duration, the accuracy of the battery management system's determination of the high-voltage circuit state can be improved, thus preventing the influence of current fluctuations on the battery management system's determination of the high-voltage circuit state.

[0086] Optionally, the high-voltage circuit state includes short-circuit state and non-short-circuit state.

[0087] Specifically, a short circuit state refers to a short circuit fault in the high-voltage circuit, while a non-short circuit state refers to the normal operation of the high-voltage circuit.

[0088] For example, Figure 6 This is a flowchart illustrating a method for a battery management system to determine the state of a high-voltage circuit, provided by an embodiment of the present invention. Based on the above embodiment, the method for a battery management system to determine the state of a high-voltage circuit is further refined to include:

[0089] S510: The battery management system determines whether the high-voltage current is greater than the first preset current; if yes, it executes S520; if no, it executes S540.

[0090] Optionally, the first preset current is greater than the maximum overload current of the battery energy distribution unit, and the first preset current is less than or equal to the maximum withstand current of any relay in the high-voltage circuit.

[0091] S520: The battery management system determines whether the duration exceeds the preset time; if yes, it executes S530; if no, it executes S540.

[0092] Optionally, the preset time is less than the maximum withstand time of any relay in the high-voltage circuit, and the preset time is greater than the maximum overload withstand time of the battery energy distribution unit.

[0093] S530, the high-voltage circuit is in a short-circuit state.

[0094] The S540 high-voltage circuit is in a non-short-circuit state.

[0095] For example, Figure 7This is a flowchart illustrating a method for a battery management system to control an integrated active-passive fuse to disconnect a high-voltage circuit, provided by an embodiment of the present invention. Based on the above embodiment, the method for a battery management system to control an integrated active-passive fuse to disconnect a high-voltage circuit is further refined to include:

[0096] S610. If the high-voltage circuit is in a short-circuit state, the battery management system determines whether the high-voltage current is less than or equal to the second preset current; if yes, then execute S620; if no, then execute S630.

[0097] Optionally, the second preset current is the withstand current corresponding to the intersection of the withstand current curve of the active-passive integrated fuse and the withstand current curve of the relay in the high-voltage circuit.

[0098] S620: The battery management system sends a cut-off signal to the active-passive integrated fuse, so that the active-passive integrated fuse actively disconnects the high-voltage circuit according to the cut-off signal.

[0099] S630, an integrated active and passive fuse, passively disconnects high-voltage circuits.

[0100] Figure 8 A flowchart illustrating another high-voltage circuit short-circuit protection method provided in an embodiment of the present invention is shown below. Figure 8 As shown, the method specifically includes the following steps:

[0101] S710, a current sensor, detects the high-voltage current in a high-voltage circuit.

[0102] The S720 current sensor sends high-voltage current to the battery management system.

[0103] S730, the battery management system obtains the high-voltage current of the high-voltage circuit corresponding to the battery energy distribution unit.

[0104] S740, the battery management system detects the voltage difference between the positive and negative terminals of the battery energy distribution unit.

[0105] For example, continue to refer to Figure 1 The M point of the positive bus and the N point of the negative bus of the high-voltage discharge circuit of the battery energy distribution unit 330 are both connected to the battery management system 320. The battery management system 320 can detect the voltage at the M point of the positive bus and the voltage at the N point of the negative bus respectively, thereby obtaining the voltage difference between the positive and negative terminals of the battery energy distribution unit 330, that is, the voltage difference between the positive and negative terminals of the battery energy distribution unit 330 = the voltage at the M point of the positive bus of the high-voltage discharge circuit - the voltage at the N point of the negative bus of the high-voltage discharge circuit.

[0106] The S750 battery management system determines the high-voltage circuit conduction state of the battery energy distribution unit based on the voltage difference between the positive and negative terminals.

[0107] If the voltage difference between the positive and negative terminals of the battery energy distribution unit is small, it can be determined that the passive integrated fuse is effective in cutting off power, and the high-voltage circuit of the battery energy distribution unit is open. If the voltage difference between the positive and negative terminals of the battery energy distribution unit is large, it can be determined that the passive integrated fuse is ineffective in cutting off power, and the high-voltage circuit of the battery energy distribution unit is closed.

[0108] The S760 battery management system controls the relays of the battery energy distribution unit to disconnect based on the conduction status of the high-voltage circuit.

[0109] From the perspective of circuit power failure safety, the battery management system needs to control the relays of the battery energy distribution unit to disconnect in different sequences or in different ways according to the conduction status of the high-voltage circuit.

[0110] For example, if the high-voltage circuit of the battery energy distribution unit is not effectively de-energized, the high-voltage circuit remains closed. In this case, the relay on the negative terminal of the high-voltage circuit must be disconnected first to ensure the safety of the high-voltage circuit relay de-energization. If the relay on the positive terminal of the high-voltage circuit is disconnected first, the relay on the positive terminal of the high-voltage circuit will generate an electric arc at the moment of de-energization due to the excessively high voltage, creating a significant safety hazard. Conversely, if the high-voltage circuit of the battery energy distribution unit is effectively de-energized, the high-voltage circuit is open, and there is no specific order for disconnecting the relays in this case.

[0111] For example, Figure 9 This is a flowchart illustrating a method for a battery management system to determine the conduction state of the high-voltage circuit of a battery energy distribution unit, provided by an embodiment of the present invention. Based on the above embodiment, the method for determining the conduction state of the high-voltage circuit of a battery energy distribution unit is further refined to include:

[0112] S810: The battery management system determines whether the voltage difference between the positive and negative terminals is less than or equal to the threshold voltage; if yes, then execute S820; if no, then execute S840.

[0113] S820, the high-voltage circuit is in the off state.

[0114] S830, the battery management system controls the main positive relay and main negative relay of the battery energy distribution unit to disconnect; execute S860.

[0115] S840, the high voltage circuit is in the on state.

[0116] S850: The battery management system controls the main negative relay of the battery energy distribution unit to disconnect, and after the main negative relay is disconnected, controls the main positive relay of the battery energy distribution unit to disconnect; execute S860.

[0117] The S860, vehicle controller, and battery management system record fault information and adjust the status of the vehicle controller and battery management system to a fault state.

[0118] It is important to note that the battery management system's detection action is set after the battery management system provides an excitation power signal to the integrated active and passive fuse Q for a certain period of time (e.g., 10ms). The battery management system then determines the polarity between the positive and negative terminals output by the battery energy distribution unit (e.g., ...). Figure 1 Is the voltage difference between point M and point N less than or equal to the threshold voltage (e.g., 10V)?

[0119] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0120] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A short-circuit protection method for a high-voltage circuit, characterized in that The high-voltage circuit short-circuit protection system comprises a battery management system and a battery energy distribution unit; the battery energy distribution unit comprises a main-passive integrated fuse; the battery management system is connected with the main-passive integrated fuse; The high-voltage circuit short-circuit protection method comprises: The battery management system acquires a high-voltage current of a high-voltage circuit corresponding to the battery energy distribution unit; The battery management system determines a high-voltage circuit state according to the high-voltage current; The battery management system controls the main-passive integrated fuse to disconnect the high-voltage circuit according to the high-voltage circuit state and the high-voltage current; After the battery management system controls the main-passive integrated fuse to disconnect the high-voltage circuit, the method further comprises: The battery management system detects a positive-negative electrode voltage difference of the battery energy distribution unit; The battery management system determines a high-voltage circuit conduction state of the battery energy distribution unit according to the positive-negative electrode voltage difference; The battery management system controls a relay of the battery energy distribution unit to disconnect according to the high-voltage circuit conduction state.

2. The high voltage circuit short protection method of claim 1, wherein, The battery energy distribution unit comprises a current sensor, and the current sensor is connected with the battery management system; Before the battery management system acquires the high-voltage current of the high-voltage circuit corresponding to the battery energy distribution unit, the method comprises: The current sensor detects the high-voltage current of the high-voltage circuit; The current sensor sends the high-voltage current to the battery management system.

3. The high voltage circuit short protection method of claim 1, wherein, The battery management system determines a high-voltage circuit state according to the high-voltage current, which comprises: The battery management system calculates a duration during which the battery management system receives the high-voltage current; The battery management system obtains the high-voltage circuit state according to the high-voltage current and the duration.

4. The high voltage circuit short protection method of claim 3, wherein, The high-voltage circuit state comprises a short-circuit state and a non-short-circuit state; The battery management system obtains the high-voltage circuit state according to the high-voltage current and the duration, which comprises: The battery management system determines whether the high-voltage current is greater than a first preset current; If not, the high-voltage circuit state is the non-short-circuit state; If yes, the battery management system determines whether the duration is greater than a preset time; If yes, the high-voltage circuit state is the short-circuit state; If not, the high-voltage circuit state is the non-short-circuit state.

5. The high voltage circuit short protection method of claim 4, wherein, The first preset current is greater than a maximum overload current of the battery energy distribution unit, and the first preset current is less than or equal to a maximum tolerance current of any relay in the high-voltage circuit; The preset time is less than a maximum tolerance time of any relay in the high-voltage circuit, and the preset time is greater than a maximum overload tolerance time of the battery energy distribution unit.

6. The high voltage circuit short protection method of claim 4, wherein, The battery management system controls the main-passive integrated fuse to disconnect the high-voltage circuit according to the high-voltage circuit state and the high-voltage current, which comprises: If the high-voltage circuit state is the short-circuit state, the battery management system determines whether the high-voltage current is less than or equal to a second preset current; If yes, the battery management system sends a cut-off signal to the active-passive integrated fuse to make the active-passive integrated fuse actively cut off the high-voltage circuit according to the cut-off signal. If no, the active-passive integrated fuse passively cuts off the high-voltage circuit.

7. The high voltage circuit short protection method of claim 6, wherein, The second preset current is a corresponding withstand current at an intersection of a withstand current curve of the active-passive integrated fuse and a withstand current curve of a relay in the high-voltage circuit.

8. The high voltage circuit short protection method of claim 1, wherein, The battery management system determines a high-voltage circuit conduction state of the battery energy distribution unit according to the positive-negative electrode voltage difference, and the determining comprises: The battery management system determines whether the positive-negative electrode voltage difference is less than or equal to a threshold voltage; If yes, the high-voltage circuit conduction state is a cut-off state; If no, the high-voltage circuit conduction state is a conduction state.

9. The high voltage circuit short protection method of claim 8, wherein, The relay of the battery energy distribution unit comprises a main positive relay and a main negative relay. The battery management system controls the relay of the battery energy distribution unit to be cut off according to the high-voltage circuit conduction state, and the controlling comprises: If the high-voltage circuit conduction state is the cut-off state, the battery management system controls the main positive relay and the main negative relay of the battery energy distribution unit to be cut off; If the high-voltage circuit conduction state is the conduction state, the battery management system controls the main negative relay of the battery energy distribution unit to be cut off, and controls the main positive relay to be cut off after the main negative relay is cut off.

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