Control method, battery management system, and storage medium

Abstract

A control method, a battery management system and a storage medium, the control method is applied to the battery management system, the battery management system includes a first circuit, a first relay, a second relay and a master control unit, the control method includes: acquiring the first current flowing through the second relay through the master control unit, and determining whether the first current is greater than or equal to a first preset value through the master control unit; when the first current is greater than or equal to the first preset value, the master control unit controls the second relay to be disconnected; the second current flowing through the first relay is acquired through the current detection unit, and the value of the second current is transmitted to the master control unit; the master control unit determines whether the first duration that the second current is greater than or equal to the second preset value is greater than or equal to the first preset duration; when the first duration is greater than or equal to the first preset duration, the master control unit controls the electronic switch to be disconnected, and the reliability of the overcurrent protection of the battery management system is improved.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, specifically to a control method, a battery management system, and a storage medium. Background Technology

[0002] Currently, when the battery management system (BMS) detects an abnormal current (such as overcurrent), the main control unit of the BMS issues a command to disconnect the charge / discharge relay in the main circuit of the BMS to cut off the circuit and protect the battery. However, when the charge / discharge relay fails (for example, the contacts of the charge / discharge relay become stuck and cannot disconnect), it can cause significant damage to the components in the circuit and the battery. In existing technology, manufacturers connect a fuse in series in the main circuit. When the charge / discharge relay fails, the circuit is cut off by the fuse blowing. However, the fusing characteristics of the fuse are affected by ambient temperature and aging, and there is a risk of false blowing or failure to blow when it is supposed to, resulting in poor reliability. Summary of the Invention

[0003] The purpose of this invention is to provide a control method, a battery management system, and a storage medium to improve the reliability of overcurrent protection in the battery management system.

[0004] To achieve the objectives of this invention, the following technical solution is provided: In a first aspect, the present invention provides a control method applied to a battery management system. The battery management system includes a first circuit, a first relay, a second relay, and a main control unit. The first relay, the second relay, and the main control unit are all connected in series with the first circuit. One end of the first circuit is connected to one end of a load, and the other end of the first circuit is connected to the other end of the load. The first relay includes an electronic switch and a current detection unit, both of which are connected in series with the first circuit. The control method includes: acquiring a first current flowing through the second relay through the main control unit, and determining whether the first current is greater than or equal to a first preset value; when the first current is greater than or equal to the first preset value, controlling the second relay to disconnect through the main control unit; acquiring a second current flowing through the first relay through the current detection unit, and transmitting the value of the second current to the main control unit; determining whether a first duration for which the second current is greater than or equal to a second preset value is greater than or equal to a first preset duration through the main control unit; and controlling the electronic switch to disconnect when the first duration is greater than or equal to the first preset duration through the main control unit.

[0005] The main control unit acquires the first current flowing through the second relay and determines whether the first current is greater than or equal to a first preset value. This allows the main control unit to detect and judge the first current of the second relay. When the first current is greater than or equal to the first preset value, the main control unit controls the second relay to disconnect. If the current exceeds the first preset value, the second relay is disconnected first to achieve preliminary protection. The current detection unit collects the second current and transmits its value to the main control unit. The main control unit determines whether the first duration for which the second current is greater than or equal to the second preset value is greater than or equal to the first preset duration. When the first duration is greater than or equal to the first preset duration, i.e., the second relay fails and cannot disconnect, the main control unit controls the electronic switch to disconnect the circuit, thus preventing damage to components and the battery. Existing technology uses a second relay and a fuse in the circuit. When the second relay fails, the fuse may blow accidentally or fail to blow, damaging components and the battery. This application improves the reliability of overcurrent protection in the battery management system.

[0006] In one embodiment, before acquiring a second current flowing through the first relay through the current detection unit and transmitting the value of the second current to the main control unit, the method further includes: acquiring a third current flowing through the first relay through the current detection unit; and controlling the electronic switch to open when the third current is greater than or equal to a second preset value, wherein the second preset value is greater than the first preset value.

[0007] The third current flowing through the first relay is obtained by the current detection unit. When the third current is greater than or equal to the second preset value, the electronic switch is controlled to open and the second preset value is set to be higher than the first preset value (severe overcurrent situation). For severe overcurrent situations where the third current is higher than the first preset value, the first switch can be directly controlled to open without the judgment of the main control unit mentioned above. This greatly improves the protection response speed during severe overcurrent short circuits, can quickly cut off the fault circuit, and avoid damage to circuit components due to severe overcurrent caused by the response delay of the main control unit's judgment.

[0008] In one embodiment, obtaining the third current flowing through the first relay through the current detection unit includes: obtaining multiple fourth currents flowing through the first relay through the current detection unit within a preset sampling time; filtering out the multiple fourth currents to retain the portion of the multiple fourth currents whose current value is greater than or equal to a first preset current and less than or equal to a second preset current to obtain multiple fifth currents, wherein the first preset current is less than the second preset current; and determining the third current based on the average value of the multiple fifth currents.

[0009] By collecting multiple fourth currents within a preset sampling time, filtering out these fourth currents, and retaining the portion of the fourth currents whose current values ​​are greater than or equal to a first preset current and less than or equal to a second preset current, multiple fifth currents are obtained. After filtering out abnormal values ​​that exceed the specified current range, a third current is determined based on the average value of the multiple fifth currents. The method of taking the average value effectively filters out invalid sampling data generated by electromagnetic interference and circuit spikes during the current sampling process, avoiding instantaneous sampling errors. At the same time, limiting the sampling current range and taking the average value makes the third current more closely match the actual current flowing through the first relay.

[0010] In one embodiment, after the electronic switch is disconnected by the main control unit when the first duration is greater than or equal to the first preset duration, the method further includes: determining the state of the battery management system based on the second current and the first duration, wherein the state of the battery management system includes at least an instantaneous short circuit state and a continuous short circuit state; and controlling the disconnection or connection of the electronic switch based on the state of the battery management system.

[0011] The state of the battery management system (BMS) is determined based on a second current and a first duration. This state then controls the opening or closing of the electronic switch. The combined approach of the second current and the first duration, where the second current is greater than or equal to a second preset value, indicates whether the excessive current is instantaneous or continuous. This allows for accurate identification of instantaneous and continuous short-circuit states in the BMS. The first switch is then controlled according to these states, avoiding over-protection against instantaneous short circuits and preventing frequent shutdowns of the BMS due to occasional current fluctuations. Simultaneously, the first switch remains open during continuous short-circuit faults to prevent damage from repeated high-current surges.

[0012] In one embodiment, determining the state of the battery management system based on the second current and the first duration includes: when the first duration is greater than or equal to the first preset duration and less than or equal to the second preset duration, the battery management system is in the instantaneous short-circuit state; when the first duration is greater than or equal to the second preset duration, the battery management system is in the continuous short-circuit state.

[0013] When the first duration is greater than or equal to the first preset duration and less than or equal to the second preset duration, it indicates that the circuit has a short period of excessive current, and the battery management system is in a momentary short-circuit state. When the first duration is greater than or equal to the second preset duration, it indicates that the circuit has a continuous excessive current for a long period, and the battery management system is in a continuous short-circuit state. By setting the period from the first preset duration to the second preset duration as a momentary short-circuit state and the period exceeding the second preset duration as a continuous short-circuit state, the quantified duration standard makes the state identification more accurate and reliable.

[0014] In one embodiment, controlling the opening or closing of the electronic switch based on the state of the battery management system includes: controlling the electronic switch to close after a third preset time period following the opening of the electronic switch; controlling the electronic switch to close when the second current after closing is greater than or equal to the second preset value; and keeping the electronic switch closed and controlling the second relay to close when the second current after closing is less than the second preset value.

[0015] The system employs a delayed power-on mechanism. By controlling the electronic switch to turn on after a third preset time interval following its initial disconnection, the system avoids current fluctuations caused by instantaneous short circuits. When the second current after power-on is greater than or equal to a second preset value, the electronic switch is disconnected. If the second current after power-on is less than the second preset value, the electronic switch remains on, and the second relay is also activated. This step-by-step strategy of delayed power-on and current verification for instantaneous short circuits avoids current fluctuations and performs secondary verification through the detection of the second current after power-on. This ensures that the short circuit fault is completely eliminated before restoring normal operation of the battery management system, preventing damage to circuit components caused by power-on before the fault is eliminated. If the second current is still greater than or equal to the second preset value after power-on, the first switch is immediately disconnected to maintain an open state for persistent short circuits, avoiding secondary damage from subsequent power-on. Furthermore, the second relay is activated upon resumption of operation, restoring normal power supply to the system.

[0016] In one embodiment, controlling the electronic switch to turn on after a third preset time period following the control of the electronic switch to turn off includes: during a first on-time period, controlling the second current after the switch to turn on to increase by a first current value every second time period; during a second on-time period, controlling the second current after the switch to turn on to increase by a second current value every second time period, wherein the first current value is less than the second current value.

[0017] By controlling the second current after conduction to increase the first current value every second interval during the first conduction period, and controlling the second current after conduction to increase the second current value every second interval during the second conduction period, with the first current value being less than the second current value, a stepped current boosting method is adopted to achieve power restoration control. Different current boosting amplitudes are set for the first and second conduction periods, so that the instantaneous current in the circuit is small at the beginning of power restoration, avoiding the surge impact of the instantaneous large current on the battery, relay, load and other devices during power restoration, and greatly reducing the current surge hazards during the power restoration process.

[0018] In one embodiment, controlling the second current after conduction to increase by a first current value during the first conduction duration includes: during the first conduction duration, making the waveform of the second current after conduction a first square wave, the first square wave including a first high current value and a first low current value; and making the duration of the first high current value less than the duration of the first low current value.

[0019] By controlling the recovery current during the first conduction duration as a square wave with a specific duty cycle, and setting the duration of the first high current value to be shorter than the duration of the first low current value, the square wave current output can more precisely control the magnitude of the current increase, avoiding irregular fluctuations caused by linear current increases and improving the stability of current control. The duty cycle design, which shortens the duration of the first high current value and lengthens the duration of the first low current value, ensures that the core components of the battery management system only experience high current for a short time during the initial recovery phase, remaining in a low-current state for most of the time, thus minimizing the current surge during the initial recovery phase.

[0020] Secondly, embodiments of this application provide a battery management system for implementing the control method described in any one of the first aspects. The battery management system includes a first circuit, a first relay, a second relay, and a main control unit. The first relay, the second relay, and the main control unit are all connected in series with the first circuit. One end of the first circuit is connected to one end of a load, and the other end of the first circuit is connected to the other end of the load. The first relay includes an electronic switch and a current detection unit, both of which are connected in series with the first circuit. The current detection unit is used to acquire a second current flowing through the first relay and transmit the value of the second current to the main control unit. The main control unit is used to acquire a first current flowing through the second relay. The main control unit is also used to determine whether the first current is greater than or equal to a first preset value. The main control unit is also used to control the second relay to disconnect when the first current is greater than or equal to the first preset value. The main control unit is also used to determine whether a first duration for which the second current is greater than or equal to the second preset value is greater than or equal to a first preset duration. The main control unit is also used to control the electronic switch to disconnect when the first duration is greater than or equal to the first preset duration.

[0021] Thirdly, embodiments of this application provide a computer-readable storage medium storing a computer program that causes a computer to execute in order to implement the method as described in any of the first aspects. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a flowchart illustrating a control method according to one embodiment; Figure 2 This is a first flowchart of the control logic of a control method according to one embodiment; Figure 3 This is a second flowchart of the control logic of a control method according to one embodiment; Figure 4 This is a schematic diagram of a prior art system architecture according to one embodiment; Figure 5 This is a schematic diagram of a battery management system architecture according to one embodiment; Figure 6 This is a schematic diagram of the structure of a control device according to one embodiment.

[0024] Explanation of reference numerals in the attached figures: 10-First relay, 101-Electronic switch, 102-Current detection unit, 103-First control unit, 104-Short circuit protection unit, 11-Second relay, 12-Main control unit, 13-Load, 600-Control device, 601-Processor, 602-Memory, 603-Program, 604-Communication interface. Detailed Implementation

[0025] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] It should be noted that when a component is said to be "fixed" to another component, it can be directly on the other component or it can be in a middle component. When a component is said to be "connected" to another component, it can be directly connected to the other component or it may be in a middle component.

[0027] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used in this invention includes any and all combinations of one or more of the associated listed items.

[0028] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0029] Please see Figure 1 , Figure 1 This is a flowchart illustrating a control method according to an embodiment of this application. The control method is applied to a battery management system, which includes a first circuit, a first relay, a second relay, and a main control unit. The first relay, the second relay, and the main control unit are all connected in series with the first circuit. One end of the first circuit is connected to one end of a load, and the other end of the first circuit is connected to the other end of the load. The first relay includes an electronic switch and a current detection unit, both of which are connected in series with the first circuit. The control method includes steps S101-S105. Please refer to... Figure 1 , Figure 2 and Figure 3 ,in, S101: Obtain the first current flowing through the second relay through the main control unit, and determine whether the first current is greater than or equal to the first preset value through the main control unit.

[0030] Optionally, the first circuit is the main power conductive loop connected to the load.

[0031] Optionally, the first relay is an intelligent relay integrating a semiconductor electronic switch and a Hall current detection unit. Optionally, the second relay is a mechanical main contactor.

[0032] Optionally, the main control unit is the control core of the battery management system and is communicatively connected to the two relays mentioned above. Optionally, the main control unit collects the first current flowing through the second relay in real time through a shunt connected in series in the branch of the second relay. The real-time current value of the first current passing through the second relay is set to a first preset value of 150A. The main control unit compares the first current with 150A in real time.

[0033] S102: When the first current is greater than or equal to the first preset value, the second relay is disconnected by controlling the main control unit.

[0034] Before acquiring the second current flowing through the first relay via the current detection unit and transmitting the value of the second current to the main control unit, the method further includes: The third current flowing through the first relay is obtained through the current detection unit; When the third current is greater than or equal to the second preset value, the electronic switch is turned off, and the second preset value is greater than the first preset value.

[0035] Optionally, the third current refers to the current collected in real time by the current detection unit of the first relay. Optionally, the second preset value is 200A, which is greater than the first preset value of 150A, and is the current threshold for triggering rapid disconnection.

[0036] Optionally, before the current detection unit transmits the second current value to the main control unit, the current detection unit collects the third current flowing through the first relay in real time through internal hardware comparison, and compares the third current with the second preset value of 200A in real time. When a sudden severe short circuit occurs on the load side and the third current instantly surges to more than 200A, the hardware protection circuit of the current detection unit directly outputs a shutdown signal to the electronic switch to control the electronic switch to quickly disconnect. In addition, the local microcontroller unit (which can independently process the detected data) reports the existence of a short circuit to the battery management system.

[0037] Optionally, the battery management system may also include a first control unit for controlling the electronic switch to disconnect.

[0038] The third current flowing through the first relay is obtained by the current detection unit. When the third current is greater than or equal to the second preset value, the electronic switch is controlled to open and the second preset value is set to be higher than the first preset value (severe overcurrent situation). For severe overcurrent situations where the third current is higher than the first preset value, the first switch can be directly controlled to open without the judgment of the main control unit mentioned above. This greatly improves the protection response speed during severe overcurrent short circuits, can quickly cut off the fault circuit, and avoid damage to circuit components due to severe overcurrent caused by the response delay of the main control unit's judgment.

[0039] The third current flowing through the first relay is obtained through the current detection unit, including: Within a preset sampling time, multiple fourth currents flowing through the first relay are obtained through the current detection unit; Multiple fourth currents are filtered out to retain the portion of the multiple fourth currents whose current values ​​are greater than or equal to the first preset current and less than or equal to the second preset current, so as to obtain multiple fifth currents, wherein the first preset current is less than the second preset current; The third current is determined based on the average of multiple fifth currents.

[0040] Optionally, the preset sampling duration is set to 10ms, which is a fixed time window for the current detection unit to collect and sample data. Optionally, the first preset current is set to 10A, which is the lower limit of the filter and is used to filter out loop leakage current and sampling noise. The second preset current is set to 600A, which is the upper limit of the filter and is used to filter out sampling spike interference.

[0041] Optionally, the fifth current is the valid sampled data after removing outliers. Optionally, within a preset sampling duration of 10ms, the current detection unit samples at a sampling frequency of 1kHz to obtain 10 raw data points of the fourth current; then, the current detection unit performs threshold filtering on the 10 fourth currents, removing data less than 10A and data greater than 600A, retaining the data in the range of 10A to 600A as the fifth current, and finally calculating the arithmetic mean of all fifth currents, and determining this average value as the third current.

[0042] By collecting multiple fourth currents within a preset sampling time, filtering out these fourth currents, and retaining the portion of the fourth currents whose current values ​​are greater than or equal to a first preset current and less than or equal to a second preset current, multiple fifth currents are obtained. After filtering out abnormal values ​​that exceed the specified current range, a third current is determined based on the average value of the multiple fifth currents. The method of taking the average value effectively filters out invalid sampling data generated by electromagnetic interference and circuit spikes during the current sampling process, avoiding instantaneous sampling errors. At the same time, limiting the sampling current range and taking the average value makes the third current more closely match the actual current flowing through the first relay.

[0043] S103: Obtain the second current flowing through the first relay through the current detection unit, and transmit the value of the second current to the main control unit.

[0044] S104: The main control unit determines whether the first duration during which the second current is greater than or equal to the second preset value is greater than or equal to the first preset duration.

[0045] S105: When the first duration is greater than or equal to the first preset duration, the electronic switch is disconnected by the main control unit.

[0046] When the first duration is greater than or equal to the first preset duration, after the electronic switch is disconnected by the main control unit, the method further includes: The state of the battery management system is determined based on the second current and the first duration. The state of the battery management system includes at least an instantaneous short circuit state and a continuous short circuit state. The state control electronic switch is opened or closed based on the battery management system.

[0047] Optional, please refer to Figure 2The specific process of this secondary protection control logic is as follows: The main control unit acquires the first current and simultaneously acquires the second current reported by the first relay. Next, it determines whether an overcurrent fault has occurred. If the determination result is no, it continues to wait; if the determination result is yes, it disconnects the second relay. Then, it determines whether a second current still exists in the circuit and whether this current is greater than or equal to a second preset value. If the determination result is no, the process ends directly; if the determination result is yes, the main control unit reports that the second relay is stuck and simultaneously sends a command to the first relay to disconnect the electronic switch. Next, the battery management system locks up, and the process terminates.

[0048] Optional, please refer to Figure 3 The specific process of the secondary protection control logic is as follows: The first relay acquires the third current in real time and determines whether the third current exceeds the second preset value. If the determination result is no, it continues to wait; if the determination result is yes, it disconnects the electronic switch and then reports the emergency shutdown alarm signal and the current data during the fault to the main control unit.

[0049] Optionally, the electronic switch is a pair of back-to-back metal-oxide-semiconductor field-effect transistors (or insulated-gate bipolar transistors). Metal-oxide-semiconductor field-effect transistors have fast switching speeds and are characterized by high-frequency operation, no electric arc, and no contact adhesion.

[0050] Optionally, the battery management system may also include multiple current sensing circuits (such as differential amplifiers and sampling resistors) and voltage sensing circuits, which can measure the current flowing through each device and the voltage across it in real time with precision.

[0051] Optionally, when a moderate overcurrent occurs on the load side and the first current reaches 150A, the main control unit sends a disconnect command to the second relay to control the second relay to disconnect, thus completing the first-level overcurrent protection.

[0052] Optionally, the main microcontroller unit of the battery management system continuously monitors the total battery voltage, total current and temperature. When the main microcontroller unit determines that a fault such as overcharge, over-discharge or general overcurrent has occurred, it first issues a control command.

[0053] Optionally, after the second relay is disconnected, the first relay remains connected in series in the closed first circuit branch. The current detection unit inside the first relay collects the second current flowing through the first relay in real time. The second current is the real-time current value of the first relay branch. The second preset value is set to 200A. The current detection unit transmits the second current value to the main control unit through a communication line (or a communication interface, which has an interface for communicating with the main microcontroller unit of the battery management system for reporting status, receiving commands, and synchronizing data). The main control unit continuously times the first duration for which the second current is greater than or equal to 200A. The first preset duration is set to 100ms. When a short circuit on the load side causes the second current to continuously exceed 200A and the cumulative first duration reaches 100ms, the main control unit sends a shutdown command to the electronic switch of the first relay to control the electronic switch to open and cut off the main circuit current.

[0054] The state of the battery management system (BMS) is determined based on a second current and a first duration. This state then controls the opening or closing of the electronic switch. The combined approach of the second current and the first duration, where the second current is greater than or equal to a second preset value, indicates whether the excessive current is instantaneous or continuous. This allows for accurate identification of instantaneous and continuous short-circuit states in the BMS. The first switch is then controlled according to these states, avoiding over-protection against instantaneous short circuits and preventing frequent shutdowns of the BMS due to occasional current fluctuations. Simultaneously, the first switch remains open during continuous short-circuit faults to prevent damage from repeated high-current surges.

[0055] The state of the battery management system is determined based on the second current and the first duration, including: When the first duration is greater than or equal to the first preset duration and less than or equal to the second preset duration, the battery management system is in a momentary short-circuit state. When the first duration is greater than or equal to the second preset duration, the battery management system is in a continuous short-circuit state.

[0056] Optionally, the second preset duration is set to 500ms, which is the time threshold for distinguishing between instantaneous short circuits and continuous short circuits. Optionally, after the main control unit obtains the first duration when the second current is greater than or equal to the second preset value, it compares the first duration with the second preset duration of 500ms. When the first duration is greater than or equal to 100ms and less than or equal to 500ms, the short circuit is determined to be an instantaneous short circuit caused by a short-term impact; when the first duration is greater than or equal to 500ms, the short circuit is determined to be a continuous short circuit where the fault point persists.

[0057] When the first duration is greater than or equal to the first preset duration and less than or equal to the second preset duration, it indicates that the circuit has a short period of excessive current, and the battery management system is in a momentary short-circuit state. When the first duration is greater than or equal to the second preset duration, it indicates that the circuit has a continuous excessive current for a long period, and the battery management system is in a continuous short-circuit state. By setting the period from the first preset duration to the second preset duration as a momentary short-circuit state and the period exceeding the second preset duration as a continuous short-circuit state, the quantified duration standard makes the state identification more accurate and reliable.

[0058] The state control electronic switch based on the battery management system is opened or closed, including: The electronic switch is turned on again after a third preset time period following the opening of the control electronic switch; When the second current after conduction is greater than or equal to the second preset value, the electronic switch is turned off. When the second current after conduction is less than the second preset value, the electronic switch remains on and the second relay is controlled to conduct.

[0059] Optionally, the third preset duration is set to 2 seconds, which is a buffer delay for waiting for the fault to dissipate after the electronic switch is turned off. Optionally, when the battery management system is determined to be in a momentary short-circuit state, the main control unit starts timing. After the third preset duration of 2 seconds has elapsed since the electronic switch was turned off, a conduction command is sent to the electronic switch to control it to turn on. After the electronic switch turns on, the current detection unit collects the second current after conduction in real time and transmits it to the main control unit. If the second current after conduction is again greater than or equal to the second preset value of 200A, it indicates that the short-circuit fault has not been eliminated. The main control unit immediately controls the electronic switch to turn off again and terminates the recovery process. If the second current after conduction is less than 200A, it indicates that the short-circuit fault has been eliminated by itself. The main control unit keeps the electronic switch in the conducting state and simultaneously sends a conduction command to the second relay to control the second relay to close.

[0060] Optionally, electronic switches can be used instead of fuses, enabling the recovery of secondary protection and preventing the entire battery pack from being scrapped due to a single fault, thus significantly reducing life cycle costs.

[0061] The system employs a delayed power-on mechanism. By controlling the electronic switch to turn on after a third preset time interval following its initial disconnection, the system avoids current fluctuations caused by instantaneous short circuits. When the second current after power-on is greater than or equal to a second preset value, the electronic switch is disconnected. If the second current after power-on is less than the second preset value, the electronic switch remains on, and the second relay is also activated. This step-by-step strategy of delayed power-on and current verification for instantaneous short circuits avoids current fluctuations and performs secondary verification through the detection of the second current after power-on. This ensures that the short circuit fault is completely eliminated before restoring normal operation of the battery management system, preventing damage to circuit components caused by power-on before the fault is eliminated. If the second current is still greater than or equal to the second preset value after power-on, the first switch is immediately disconnected to maintain an open state for persistent short circuits, avoiding secondary damage from subsequent power-on. Furthermore, the second relay is activated upon resumption of operation, restoring normal power supply to the system.

[0062] After a third preset time period following the opening of the control electronic switch, the control electronic switch is turned on, including: During the first conduction duration, the second current after conduction is controlled to increase by the first current value every second duration; During the second conduction duration, the second current after conduction is controlled to increase by a second current value every second duration, and the first current value is less than the second current value.

[0063] Optionally, for non-permanent faults that are judged to be potentially recoverable (such as instantaneous impact), the main microcontroller unit of the battery management system can send a pre-power-on command to the first relay after a certain delay or after meeting specific conditions (such as no abnormality in the system self-test). After receiving the command, the first relay can control the electronic switch (transistor) to slowly turn on in a low duty cycle mode.

[0064] Optionally, if the current remains normal, the circuit is fully turned on, and the battery management system returns to normal. Optionally, if the current becomes abnormal again, the circuit is immediately turned off again, and a permanent fault is reported, requiring manual intervention. This enables fault information reporting, supports remote diagnostics and predictive maintenance, and provides advanced diagnostic functions such as main relay health status monitoring.

[0065] By controlling the second current after conduction to increase the first current value every second interval during the first conduction period, and controlling the second current after conduction to increase the second current value every second interval during the second conduction period, with the first current value being less than the second current value, a stepped current boosting method is adopted to achieve power restoration control. Different current boosting amplitudes are set for the first and second conduction periods, so that the instantaneous current in the circuit is small at the beginning of power restoration, avoiding the surge impact of the instantaneous large current on the battery, relay, load and other devices during power restoration, and greatly reducing the current surge hazards during the power restoration process.

[0066] During the first conduction duration, the second current after conduction is controlled to increase by the value of the first current, including: During the first conduction duration, the waveform of the second current after conduction is a first square wave, which includes a first high current value and a first low current value. Make the duration of the first high current value shorter than the duration of the first low current value.

[0067] Optionally, the current of the first square wave can be periodically switched between two values, high and low.

[0068] Optionally, the first high current value is set to 50A, which is the current value during the high-level phase of the square wave, and the first low current value is set to 10A, which is the current value during the low-level phase of the square wave. Optionally, during the slow rise phase of the first conduction duration, the main control unit controls the electronic switch to periodically turn on and off, so that the second current waveform after conduction presents the first square wave, where the period of the first square wave is 50ms, the duration of the first high current value of 50A is 10ms, and the duration of the first low current value of 10A is 40ms. The duration of the high current is significantly shorter than the duration of the low current, resulting in a lower average current. Even if there is an unresolved short-circuit fault in the circuit, it can limit the short-circuit energy and reduce the fault impact. At the same time, it gradually detects the circuit status, improving the safety of the test conduction process.

[0069] By controlling the recovery current during the first conduction duration as a square wave with a specific duty cycle, and setting the duration of the first high current value to be shorter than the duration of the first low current value, the square wave current output can more precisely control the magnitude of the current increase, avoiding irregular fluctuations caused by linear current increases and improving the stability of current control. The duty cycle design, which shortens the duration of the first high current value and lengthens the duration of the first low current value, ensures that the core components of the battery management system only experience high current for a short time during the initial recovery phase, remaining in a low-current state for most of the time, thus minimizing the current surge during the initial recovery phase.

[0070] Optionally, the first relay includes a voltage detection circuit. The main microcontroller unit of the battery management system can issue a command to perform a sticking diagnosis on the first relay before the system is powered on or during standby. Optionally, the main microcontroller unit only commands the first relay to conduct briefly to detect whether the battery voltage appears at the load terminal of the first relay. If so, it indicates that the first relay has already stuck when it is not engaged.

[0071] Please refer to Figure 4In existing technology, the first level of protection (active protection) involves the control module issuing a command to disconnect the main positive and negative relays on the high-voltage side of the main circuit when an abnormal current (such as overcurrent) is detected, thereby cutting off the circuit and protecting the battery. The battery then stops supplying power to the load-side electrical components. The second level of protection (passive protection) involves connecting a fuse in series on one side of the battery pack in the main circuit. When the first level of protection fails (e.g., the relay contacts stick and cannot disconnect), or when a momentary extreme short circuit occurs, the huge short-circuit current will cause the fuse to blow, permanently cutting off the circuit by burning itself, preventing catastrophic accidents such as thermal runaway. However, because the fuse's fusing characteristics are greatly affected by ambient temperature and aging, there is a risk of false blowing or failure to blow when it should. Moreover, once the fuse blows, the entire battery pack is completely rendered unusable, requiring replacement of the fuse and even the entire relay box, resulting in extremely high maintenance costs and rendering the entire battery pack unusable. Furthermore, the fuse is a passive component; its operation is without warning and cannot report fault information after activation. Fault prediction and post-incident root cause analysis are not possible.

[0072] Optionally, the method of this application can also be applied to overcharge, over-discharge, general overcurrent, and excessively high temperature. The current in this application can also be modified to correspond to voltage, temperature, etc., without limitation.

[0073] In summary, the main control unit acquires the first current flowing through the second relay and determines whether the first current is greater than or equal to a first preset value. This allows the main control unit to detect and judge the first current of the second relay. When the first current is greater than or equal to the first preset value, the main control unit controls the second relay to disconnect. If the current exceeds the first preset value, the second relay is disconnected first to achieve preliminary protection. The current detection unit collects the second current and transmits its value to the main control unit. The main control unit determines whether the first duration for which the second current is greater than or equal to the second preset value is greater than or equal to the first preset duration. When the first duration is greater than or equal to the first preset duration, i.e., the second relay fails and cannot disconnect, the main control unit controls the electronic switch to disconnect the circuit, thus preventing damage to components and the battery. In contrast, existing technologies use a second relay and a fuse in the circuit. When the second relay fails, the fuse may blow accidentally or fail to blow, damaging components and the battery. This application improves the reliability of overcurrent protection in the battery management system.

[0074] Please see Figure 5 , Figure 5 This is a schematic diagram of a battery management system architecture according to an embodiment of this application. Figure 5As shown, the battery management system includes a first circuit, a first relay 10, a second relay 11, a main control unit 12, an electronic switch 101, a current detection unit 102, a first control unit 103, and a short-circuit protection unit 104. The battery management system is used to implement the control method described above. One end of the first relay 10 is connected to one end of the main control unit 12, and the other end of the first relay 10 is used to connect to one end of the load 13. The other end of the main control unit 12 is connected to one end of the second relay 11, and the other end of the second relay 11 is connected to the other end of the load 13. The first relay 10 includes an electronic switch 101, a current detection unit 102, and a first control unit 103. One end of the electronic switch 101 is connected to one end of the load 13, and the other end of the electronic switch 101 is connected to one end of the current detection unit 102. The other end of the current detection unit 102 is connected to one end of the first control unit 103, and the other end of the first control unit 103 is connected to one end of the main control unit 12. The current detection unit 102 is used to acquire the second current flowing through the first relay 10 and transmit the value of the second current to the main control unit 12. The main control unit 12 is used to acquire the first current flowing through the second relay 11. The main control unit 12 is also used to determine whether the first current is greater than or equal to a first preset value. The main control unit 12 is also used to control the second relay 11 to disconnect when the first current is greater than or equal to the first preset value. The main control unit 12 is also used to determine whether the first duration for which the second current is greater than or equal to the second preset value is greater than or equal to the first preset duration. The main control unit 12 is also used to control the electronic switch 101 to disconnect when the first duration is greater than or equal to the first preset duration. The short-circuit protection unit is used to protect the first relay 10 during a short circuit.

[0075] Please see Figure 6 , Figure 6 This is a schematic diagram of the structure of a control device according to an embodiment of this application. Figure 6 As shown, the control device 600 includes a processor 601, a memory 602, a communication interface 604, and at least one program 603. The program 603 is stored in the memory 602 and configured to be executed by the processor 601. The program includes instructions for performing the following steps: The main control unit obtains the first current flowing through the second relay and determines whether the first current is greater than or equal to the first preset value. When the first current is greater than or equal to the first preset value, the second relay is disconnected by the main control unit. The second current flowing through the first relay is obtained through the current detection unit, and the value of the second current is transmitted to the main control unit. The main control unit determines whether the first duration during which the second current is greater than or equal to the second preset value is greater than or equal to the first preset duration. When the first duration is greater than or equal to the first preset duration, the electronic switch is disconnected by the main control unit.

[0076] In one possible example, the program specifically executes the instructions for the following steps: The third current flowing through the first relay is obtained through the current detection unit; When the third current is greater than or equal to the second preset value, the electronic switch is turned off, and the second preset value is greater than the first preset value.

[0077] In one possible example, the program specifically executes the instructions for the following steps: Within a preset sampling time, multiple fourth currents flowing through the first relay are obtained through the current detection unit; Multiple fourth currents are filtered out to retain the portion of the multiple fourth currents whose current values ​​are greater than or equal to the first preset current and less than or equal to the second preset current, so as to obtain multiple fifth currents, wherein the first preset current is less than the second preset current; The third current is determined based on the average of multiple fifth currents.

[0078] In one possible example, the program specifically executes the instructions for the following steps: The state of the battery management system is determined based on the second current and the first duration. The state of the battery management system includes at least an instantaneous short circuit state and a continuous short circuit state. The state control electronic switch is opened or closed based on the battery management system.

[0079] In one possible example, the program specifically executes the instructions for the following steps: When the first duration is greater than or equal to the first preset duration and less than or equal to the second preset duration, the battery management system is in a momentary short-circuit state. When the first duration is greater than or equal to the second preset duration, the battery management system is in a continuous short-circuit state.

[0080] In one possible example, the program specifically executes the instructions for the following steps: The electronic switch is turned on again after a third preset time period following the opening of the control electronic switch; When the second current after conduction is greater than or equal to the second preset value, the electronic switch is turned off. When the second current after conduction is less than the second preset value, the electronic switch remains on and the second relay is controlled to conduct.

[0081] In one possible example, the program specifically executes the instructions for the following steps: During the first conduction duration, the second current after conduction is controlled to increase by the first current value every second duration; During the second conduction duration, the second current after conduction is controlled to increase by a second current value every second duration, and the first current value is less than the second current value.

[0082] In one possible example, the program specifically executes the instructions for the following steps: During the first conduction duration, the waveform of the second current after conduction is a first square wave, which includes a first high current value and a first low current value. Make the duration of the first high current value shorter than the duration of the first low current value.

[0083] Those skilled in the art will understand that, for ease of explanation, Figure 6 Only one memory and processor are shown in the illustration. In a real terminal or server, multiple processors and memories may exist. Memory can also be called storage medium or storage device, etc., and this application does not limit this.

[0084] It should be understood that in the embodiments of this application, the processor may be a Central Processing Unit (CPU), or it may be other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The processor may also be a general-purpose microprocessor, graphics processing unit (GPU), or one or more integrated circuits to execute relevant programs to achieve the functions required by the embodiments of this application.

[0085] The processor can also be an integrated circuit chip with signal processing capabilities. In implementation, each step of this application can be completed through integrated logic circuits in the processor hardware or instructions in software form. The aforementioned processor can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The steps of the methods disclosed in the embodiments of this application can be directly manifested as execution by a hardware decoding processor, or execution by a combination of hardware and software modules in the decoding processor. The software modules can be located in random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, or other mature storage media in the art. This storage medium is located in memory; the processor reads information from the memory and, in conjunction with its hardware, completes the functions required by the units included in the image transaction contract generation method, apparatus, and storage medium of the embodiments of this application.

[0086] It should also be understood that the memory mentioned in the embodiments of this application can be volatile memory or non-volatile memory, or may include both volatile and non-volatile memory. Non-volatile memory can be read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), or flash memory. Volatile memory can be random access memory (RAM), which is used as an external cache. By way of example, but not limitation, many forms of RAM are available, such as Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), Synchronous DRAM (SDRAM), Double Data Rate SDRAM (DDR SDRAM), Enhanced Synchronous DRAM (ESDRAM), Synchlink DRAM (SLDRAM), and Direct Rambus RAM (DR RAM). The memory can also be, but is not limited to, Compact Disc Read-Only Memory (CD-ROM) or other optical disc storage, optical disc storage (including compressed discs, laser discs, optical discs, digital universal discs, Blu-ray discs, etc.), magnetic disk storage media, or other magnetic storage devices, or any other medium capable of carrying or storing desired program code in the form of instructions or data structures that can be accessed by a computer. The memory can exist independently and be connected to the processor via a bus. The memory can also be integrated with the processor. The memory can store programs. When the program stored in the memory is executed by the processor, the processor is used to execute the various steps of the determination method in the above embodiments of this application.

[0087] It should be noted that when the processor is a general-purpose processor, DSP, ASIC, FPGA, or other programmable logic device, discrete gate or transistor logic device, or discrete hardware component, the memory (storage module) is integrated into the processor. It should be noted that the memory described herein is intended to include, but is not limited to, these and any other suitable types of memory.

[0088] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0089] In implementation, each step of the above method can be completed by integrated logic circuits in the processor's hardware or by instructions in software. The steps of the method disclosed in the embodiments of this application can be directly implemented by a hardware processor, or by a combination of hardware and software modules in the processor. The software modules can reside in mature storage media in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, or registers. This storage medium is located in memory, and the processor reads information from the memory and, in conjunction with its hardware, completes the steps of the above method. To avoid repetition, detailed descriptions are omitted here.

[0090] Those skilled in the art will recognize that the various illustrative logical blocks (ILBs) and steps described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this application.

[0091] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented, in whole or in part, as a computer-programmed program product. A computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a processor, all or part of the flow or function according to the embodiments of this application is generated. The computer can be a general-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic) or wireless (e.g., infrared, wireless, microwave, etc.) means, or from one website, computer, server, or data center to a mobile phone processor via a wired means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk), an optical medium (e.g., DVD), or a semiconductor medium (e.g., solid-state drive), etc.

[0092] The above description discloses only one preferred embodiment of the present invention, and should not be construed as limiting the scope of the present invention. Those skilled in the art will understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A control method, characterized in that, The control method is applied to a battery management system, which includes a first circuit, a first relay, a second relay, and a main control unit. The first relay, the second relay, and the main control unit are all connected in series with the first circuit. One end of the first circuit is connected to one end of a load, and the other end of the first circuit is connected to the other end of the load. The first relay includes an electronic switch and a current detection unit, both of which are connected in series with the first circuit. The control method includes: The main control unit obtains the first current flowing through the second relay, and determines whether the first current is greater than or equal to a first preset value. When the first current is greater than or equal to the first preset value, the second relay is disconnected by the main control unit; The second current flowing through the first relay is obtained through the current detection unit, and the value of the second current is transmitted to the main control unit. The main control unit determines whether the first duration during which the second current is greater than or equal to the second preset value is greater than or equal to the first preset duration. When the first duration is greater than or equal to the first preset duration, the electronic switch is turned off by the main control unit.

2. The control method according to claim 1, characterized in that, Before acquiring the second current flowing through the first relay through the current detection unit and transmitting the value of the second current to the main control unit, the method further includes: The third current flowing through the first relay is obtained through the current detection unit; When the third current is greater than or equal to the second preset value, the electronic switch is controlled to open, and the second preset value is greater than the first preset value.

3. The control method according to claim 2, characterized in that, The step of obtaining the third current flowing through the first relay through the current detection unit includes: Within a preset sampling time, multiple fourth currents flowing through the first relay are acquired through the current detection unit; Multiple fourth currents are filtered out to retain the portion of the multiple fourth currents whose current value is greater than or equal to a first preset current and less than or equal to a second preset current, so as to obtain multiple fifth currents, wherein the first preset current is less than the second preset current; The third current is determined based on the average value of the plurality of fifth currents.

4. The control method according to any one of claims 1 to 3, characterized in that, When the first duration is greater than or equal to the first preset duration, after the electronic switch is disconnected by the main control unit, the method further includes: The state of the battery management system is determined based on the second current and the first duration, and the state of the battery management system includes at least an instantaneous short circuit state and a continuous short circuit state. The electronic switch is turned on or off based on the state of the battery management system.

5. The control method according to claim 4, characterized in that, Determining the state of the battery management system based on the second current and the first duration includes: When the first duration is greater than or equal to the first preset duration and less than or equal to the second preset duration, the battery management system is in the instantaneous short-circuit state; When the first duration is greater than or equal to the second preset duration, the battery management system is in the continuous short-circuit state.

6. The control method according to claim 5, characterized in that, The method of controlling the opening or closing of the electronic switch based on the state of the battery management system includes: After a third preset time period following the control of the electronic switch being turned off, the electronic switch is turned on. When the second current after conduction is greater than or equal to the second preset value, the electronic switch is controlled to disconnect. When the second current after the circuit is turned on is less than the second preset value, the electronic switch is kept on and the second relay is controlled to turn on.

7. The control method according to claim 6, characterized in that, The step of controlling the electronic switch to turn on after a third preset time period following the control of the electronic switch to turn off includes: During the first conduction duration, the second current after conduction is controlled to increase by the first current value every second duration; During the second conduction duration, the second current after conduction is controlled to increase by a second current value every second duration, wherein the first current value is less than the second current value.

8. The control method according to claim 7, characterized in that, During the first conduction duration, controlling the second current after conduction to increase by a first current value includes: During the first conduction duration, the waveform of the second current after conduction is a first square wave, which includes a first high current value and a first low current value. The duration of the first high current value is made shorter than the duration of the first low current value.

9. A battery management system, characterized in that, To implement the control method as described in any one of claims 1 to 8, the battery management system includes a first circuit, a first relay, a second relay, and a main control unit. The first relay, the second relay, and the main control unit are all connected in series with the first circuit. One end of the first circuit is connected to one end of a load, and the other end of the first circuit is connected to the other end of the load. The first relay includes an electronic switch and a current detection unit, both of which are connected in series with the first circuit. The current detection unit is used to acquire the second current flowing through the first relay and transmit the value of the second current to the main control unit. The main control unit is configured to acquire a first current flowing through the second relay; the main control unit is also configured to determine whether the first current is greater than or equal to a first preset value; the main control unit is also configured to control the second relay to disconnect when the first current is greater than or equal to the first preset value; the main control unit is also configured to determine whether a first duration for which the second current is greater than or equal to a second preset value is greater than or equal to a first preset duration; the main control unit is also configured to control the electronic switch to disconnect when the first duration is greater than or equal to the first preset duration.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that causes a computer to execute in order to implement the method as described in any one of claims 1 to 8.

Images