Power battery system and control method therefor

Abstract

A power battery system and a control method therefor. The system comprises: multiple power battery branches (1) connected in parallel and configured to monitor and transmit key data; high-voltage boxes (2) connected to the multiple power battery branches (1) in one-to-one correspondence; and a vehicle combiner cabinet (3) connected to all of the high-voltage boxes (2), the vehicle combiner cabinet (3) being configured to generate control instructions on the basis of the key data. The high-voltage boxes (2) are configured to forward all the key data to the vehicle combiner cabinet (3), and respectively forward the control instructions to the power battery branches (1) connected to the high-voltage boxes in one-to-one correspondence, so as to control all the power battery branches (1) to supply power to a vehicle load.

Description

Power battery system and control method

[0001] This application claims priority to Chinese Patent Application No. 202411748095.5, filed with the Chinese Patent Office on November 29, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, for example to a power battery system and control method. Background Technology

[0003] In urban rail transit, multi-unit energy storage vehicles have become an emerging mode of transportation. As the power source for these vehicles, the control technology of the power battery system is crucial to the reliability and safety of the system.

[0004] With the continuous development of control technology, power battery systems have achieved faster and more accurate monitoring and response to abnormal situations such as overcharging, over-discharging, short circuits, and high temperatures in battery packs and individual cells. However, the fault redundancy capability of power battery systems in related technologies is relatively weak. There is a problem that the consistency of individual cells cannot be guaranteed when powering on, off, and charging under load. When partial faults occur, it is not possible to control the faulty part individually, which can easily lead to the failure of the entire power battery system and the inability of the vehicle to operate. Summary of the Invention

[0005] This application proposes a power battery system and control method, which solves the problem that the faulty battery pack cannot be controlled and isolated independently during a power battery system failure, resulting in the vehicle losing high-voltage power supply and being unable to drive normally. It also improves the fire control logic and enhances vehicle operating efficiency and reliability.

[0006] This application provides a power battery system, including:

[0007] Multiple power battery branches connected in parallel, wherein the power battery branches are configured to monitor and transmit key data;

[0008] Multiple high-voltage boxes, each connected to a corresponding branch of the power battery; and

[0009] A vehicle combiner cabinet, which is connected to all the high-voltage boxes, is configured to generate control commands based on the key data;

[0010] The multiple high-voltage boxes are configured to forward all the key data to the vehicle combiner cabinet and forward the control commands to the multiple power battery branches connected to them one by one, so as to control the multiple power battery branches to supply power to the vehicle load.

[0011] In some embodiments, each of the power battery branches includes multiple battery boxes connected in series, the battery boxes being configured to supply power to the vehicle load.

[0012] In some embodiments, the vehicle combiner cabinet includes a first battery management unit, each high-voltage box includes a second battery management unit, and each battery box includes a third battery management unit;

[0013] The first battery management unit is communicatively connected to all the second battery management units, so that the multiple high-voltage boxes forward the key data sent by the multiple power battery branches corresponding to them to the vehicle combiner cabinet.

[0014] The second battery management unit is communicatively connected to the corresponding third battery management unit, so that the plurality of high-voltage boxes forward the control commands to the plurality of power battery branches that are connected one-to-one with the plurality of high-voltage boxes.

[0015] In some implementations, the third battery management unit is configured as follows:

[0016] In response to the detection that the battery charging button is triggered or the detection that the vehicle charging plug is connected to the charger, the insulation detection function is activated to obtain the insulation detection result of the corresponding battery box.

[0017] In some implementations, the first battery management unit is configured as follows:

[0018] In response to the detection that the battery input button is triggered and the insulation detection function of all the third battery management units is turned off, it is determined whether all the insulation detection results are qualified;

[0019] In response to all the insulation test results being qualified, the multiple contactors in the vehicle combiner cabinet are controlled to close sequentially according to a first preset order;

[0020] Based on all the received key data, the key data with the highest value is determined as the first key data, and the power battery branch that sends the first key data is designated as the first power battery branch.

[0021] Send the control command to the first power battery branch to control the first power battery branch to be powered on at high voltage.

[0022] Based on the first power battery branch after high-voltage power-on, the control command is sent sequentially to the remaining power battery branches to perform high-voltage power-on in order to supply power to the vehicle load.

[0023] In some implementations, the first battery management unit is configured as follows:

[0024] In response to detecting that the vehicle charging plug is connected to the charger and that the insulation detection function of all the third battery management units is turned off, it is determined whether all the insulation detection results are qualified;

[0025] In response to all the insulation test results being qualified, the multiple contactors in the vehicle combiner cabinet are controlled to close sequentially according to the second preset order;

[0026] Based on all the received key data, the key data with the lowest value is determined as the second key data, and the power battery branch that sends the second key data is designated as the second power battery branch.

[0027] Send the control command to the second power battery branch to control the second power battery branch to perform high-voltage power-on;

[0028] Based on the second power battery branch after high voltage power-on, the control command is sent to the remaining power battery branches in sequence to perform high voltage power-on, so as to charge all the battery boxes and monitor whether they have reached the charging cut-off condition.

[0029] In response to the presence of one of the battery boxes reaching the charging cutoff condition, charging of all the battery boxes is stopped, and a charging end command is sent to the charger.

[0030] In some implementations, the first battery management unit is configured as follows:

[0031] In response to the high-voltage power-off button being triggered, multiple contactors in the vehicle combiner cabinet are controlled to disconnect in a third preset order, and based on a preset delay, all contactors in all power battery branches are controlled to disconnect in a fourth preset order to stop power supply to the vehicle load.

[0032] In some embodiments, the third battery management unit is further configured to:

[0033] In response to a loss of communication with the second battery management unit or the detection of a corresponding battery box fault, the contactor in the corresponding power battery branch is disconnected.

[0034] In some embodiments, the power battery system further includes multiple fire-fighting modules, which are connected one-to-one with the multiple power battery branches. Each fire-fighting module includes multiple sensors configured to monitor the fire situation of the corresponding power battery branch and trigger a fire warning of the corresponding level.

[0035] This application also provides a control method applied to the power battery system described above, comprising:

[0036] In response to the detection that the battery charging button is triggered or the detection that the vehicle charging plug is connected to the charger, key data in all power battery branches are acquired.

[0037] All the key data are sent to the vehicle combiner box through multiple high-voltage boxes, so that the vehicle combiner box can generate control commands based on all the key data;

[0038] The control commands are forwarded through the multiple high-voltage boxes to the multiple power battery branches that are connected one-to-one with the multiple high-voltage boxes, so as to control all the power battery branches to charge or supply power to the vehicle load. Attached Figure Description

[0039] Figure 1 is a topology diagram of a multi-pack energy storage vehicle power battery system in related technologies;

[0040] Figure 2 is a schematic diagram of an embodiment of the power battery system provided in this application;

[0041] Figure 3 is a topology diagram of an embodiment of the power battery system provided in this application;

[0042] Figure 4 is a schematic diagram of an embodiment of the BMS architecture in the power battery system provided in this application;

[0043] Figure 5 is a block diagram of an embodiment of the control method provided in this application. Detailed Implementation

[0044] The embodiments of this application will be described below with reference to the accompanying drawings.

[0045] In this application, all uses of the terms "first" and "second" are for the purpose of distinguishing two entities or parameters with the same name but different names. It is clear that "first" and "second" are only for the convenience of expression and should not be construed as limiting the embodiments of this application. Subsequent embodiments will not explain this in detail.

[0046] Figure 1 illustrates a multi-unit energy storage vehicle power battery system from a related technology. It employs a centralized power supply method to the train loads. Taking a three-unit vehicle as an example, multiple power battery units are connected to a high-voltage box via a high-voltage bus, and then the high-voltage box centrally supplies power to multiple loads on the vehicle. The charging process is similar, with the output from the ground charger to the high-voltage box, which then charges multiple power battery units. In this scheme, each power battery unit cannot be controlled by its own independent contactor; instead, it is uniformly controlled by the main positive contactor and the main negative contactor in the system. When a fault occurs, the fault control logic of the related technology is as follows: during operation, if a serious fault occurs that affects safety, such as overcurrent, overvoltage, undervoltage, or overtemperature affecting the entire system, requiring the main contactor to be disconnected; if the Battery Management System (BMS) experiences a communication failure or loss of connection with the vehicle; or if a single battery branch, battery box, or individual battery cell experiences overcurrent, overvoltage, undervoltage, or overtemperature, the entire power battery system is disconnected by disconnecting the main positive contactor and the main negative contactor.

[0047] However, the above fault control logic has the following shortcomings:

[0048] 1. Inability to isolate single-cluster faults. The power battery system lacks the ability to independently isolate individual power battery clusters, meaning that when a power battery cluster or a single battery cell fails, the main positive and main negative contactors of the entire system must be disconnected. This not only causes the entire vehicle to lose high-voltage power supply, rendering the vehicle unable to operate normally.

[0049] 2. Lack of redundancy in total output. The main positive and main negative contactors of the power battery system lack redundancy design. If a contactor fails, such as being unable to engage or disengage, the entire vehicle will completely lose high-voltage power supply or be unable to complete high-voltage power-down operations. This design leads to vehicle operation interruption, affecting passenger comfort, and may also cause malfunctions or damage to related equipment, further increasing maintenance costs and safety risks.

[0050] 3. The control logic is too simple. The control logic of the power battery system is relatively simple, and the operation of powering on and off under load cannot be precisely managed, which may cause the consistency of individual battery cells to deteriorate, thereby damaging related components.

[0051] 4. Inadequate fire control logic. The fire control logic of the power battery system has imperfections, making it prone to missed or false alarms, thus weakening the system's safety. Especially in emergencies, the inability to accurately detect and handle fire risks may lead to delays in response or false triggering of protective measures, further threatening the safety of the vehicle and passengers.

[0052] Safety and reliability are core concerns in the control technology of power battery systems for multi-pack energy storage vehicles. To address the aforementioned deficiencies in power battery systems of related technologies, this application designs a reasonable switching sequence for control devices and a load startup sequence, which plays a crucial role in the safe and reliable operation of the power battery system. Simultaneously, electrical fault redundancy technology is an important means of improving system reliability and availability. This technology, by adding auxiliary components, equipment, or systems, can immediately replace and operate in the event of a failure in the main component or main system, ensuring normal system operation. This application uses electrical fault redundancy technology in the control of the power battery system, greatly improving the safety and reliability of the power battery system and preventing the entire power battery system from failing and causing the vehicle to be inoperable when a partial fault occurs.

[0053] A first aspect of this application provides a power battery system. As shown in FIG2, the power battery system includes:

[0054] Multiple power battery branches 1 connected in parallel are configured to monitor and transmit key data;

[0055] Multiple high-voltage boxes 2 are connected one-to-one with multiple power battery branches 1; and

[0056] The vehicle combiner cabinet 3, which is connected to all high-voltage boxes 2, is configured to generate control commands based on key data;

[0057] The high-voltage box 2 is configured to forward all key data to the vehicle combiner cabinet 3 and forward control commands to multiple power battery branches 1 that are connected to it one by one, so as to control the multiple power battery branches 1 to supply power to the vehicle load.

[0058] In some implementations, as shown in Figure 3, taking a three-unit energy storage vehicle as an example, the power battery system of this application adopts three clusters of power battery branches connected in parallel. Each cluster of power battery branches consists of multiple battery boxes connected in series, such as the three battery boxes connected in series in Figure 3. Each cluster of power battery branches is located in a different unit of the vehicle. The charging and discharging high-voltage bus of each cluster of power battery branches is output from its corresponding connected high-voltage box to the vehicle's combiner cabinet for grid connection, and then supplies power to the vehicle's load. A battery management unit is present in the vehicle combiner cabinet, the high-voltage box, and each battery box of each power battery branch. The architecture of the power battery system, from high to low, consists of the BMS master control of the vehicle combiner cabinet, the BMS master control of the high-voltage box, and the BMS slave control of the battery boxes, as shown in Figure 4. Each cluster of power battery branches is also equipped with a fire suppression system, controlled by the BMS master control in the vehicle combiner cabinet. The power battery branch is connected to the corresponding high-voltage box via a high-voltage bus to achieve external discharge and self-charging. Simultaneously, the power battery branch communicates with the BMS master controller in the high-voltage box, feeding back key data of the power battery branch and individual battery cells, including temperature, voltage, and current. The high-voltage box controls the charging and discharging of its corresponding power battery branch through the switching of contactors within the box. The vehicle combiner cabinet is connected to the high-voltage box via a high-voltage busbar, controlling the charging and discharging of all power battery branches through the switching of contactors within the cabinet. The BMS master controller in the vehicle combiner cabinet communicates with the BMS master controller in the high-voltage box to receive key data, performs logical operations based on the key data, and issues control commands. It also communicates with the Train Control and Management System (TCMS).

[0059] The power battery system of this application, through a hierarchical architecture of power battery branches, high-voltage box, and vehicle combiner cabinet, makes the structure of the power battery system clearer. The modular design of the power battery branches, combined with the distributed design of the high-voltage box, realizes the fault isolation function, making the power battery branches easy to maintain and replace independently, reducing the impact of single-point failures on overall operation. After a single power battery branch fails, the output of this power battery branch can be cut off, and other power battery branches can supply power to the vehicle normally. This enables reasonable control of the working state of the power battery system under power battery system failure conditions, maximizing the guarantee of system operation function in the event of system failure, reducing the impact on vehicle operation, and thus improving vehicle operating efficiency and reliability.

[0060] In some implementations, the power battery branch also includes multiple battery boxes connected in series, configured to supply power to the power battery system.

[0061] In some implementations, the vehicle combiner cabinet further includes a first battery management unit, the high-voltage box further includes a second battery management unit, and the battery box further includes a third battery management unit; the first battery management unit is communicatively connected to the second battery management unit so that the high-voltage box forwards all key data to the vehicle combiner cabinet; the second battery management unit is communicatively connected to the corresponding third battery management unit so that the high-voltage box forwards control commands to the power battery branches that are connected to them one by one.

[0062] In some implementations, the first battery management unit is the BMS master controller, the second battery management unit is the BMS master controller, and the third battery management unit is the BMS slave controller. The BMS master controller of the high-voltage box communicates with multiple BMS slave controllers in the power battery branch and the BMS master controller of the vehicle combiner cabinet. It receives control commands issued by the BMS master controller and forwards the control commands to the BMS slave controllers. At the same time, it receives key data fed back by the BMS slave controllers and feeds the key data back to the BMS master controller, playing a connecting role between the upper and lower levels.

[0063] In some implementations, the third battery management unit is configured to activate an insulation detection function to obtain insulation detection results of the battery box in response to detecting that the battery charging button is triggered or that the vehicle charging plug is connected to the charger.

[0064] In some implementations, the first battery management unit is configured to: in response to detecting that the battery charging button is triggered and the insulation detection function of all third battery management units is turned off, determine whether all insulation detection results are qualified; if all insulation detection results are qualified, control multiple contactors in the vehicle combiner cabinet to close sequentially according to a first preset order; based on all received key data, determine the key data with the highest data value as the first key data, and designate the power battery branch that sent the first key data as the first power battery branch; send a control command to the first power battery branch to control the first power battery branch to perform high-voltage power-on; based on the first power battery branch after high-voltage power-on, send control commands sequentially to the remaining power battery branches to perform high-voltage power-on in order to supply power to the vehicle load.

[0065] In some implementations, pressing the battery input button connects to 24V low-voltage power, activating the vehicle. The BMS receives power and performs a self-test, during which insulation checks are conducted on multiple power battery branches. This insulation check is completed before all contactors in the high-voltage box connected to each power battery branch are closed. All contactors in the high-voltage box can only be closed after the insulation check is passed and the insulation check function is disabled. Once all power battery branches have passed the self-test, the high-voltage power-on process begins. The power-on logic is explained using a three-car train energy storage vehicle as an example:

[0066] (1) The BMS master control controls multiple contactors in the vehicle bus cabinet to close in the first preset sequence. First, it controls the discharge main negative contactor in the vehicle bus cabinet to close, and after an interval of 500ms, it controls the electric drive contactor and the power supply contactor to close simultaneously.

[0067] (2) After all the contactors in the discharge circuit of the vehicle combiner cabinet are closed for 1 second, the power battery branch with the highest total voltage value (i.e., the first power battery branch) is selected to precharge the capacitor at the load point of the vehicle according to the total voltage value sent by all power battery branches. A control command is sent to the first power battery branch to close its internal main negative contactor. After an interval of 500ms, its internal pre-charging contactor is closed to start pre-charging. When the voltage sensor in the first power battery branch detects that the load terminal voltage rises to a preset proportion of the total voltage of the first power battery branch, such as 90%, the main positive contactor inside the first power battery branch is closed, and after a delay of 5s, its internal pre-charging contactor is opened. A preset maximum load power request for the whole vehicle is sent to the BMS master control to complete the control of the high voltage power-on of the first power battery branch; the preset maximum load power request for the whole vehicle is 1 / 3 of the maximum load power request for the whole vehicle.

[0068] (3) After pre-charging, close the main negative contactor of the remaining power battery branches whose voltage difference with the first power battery branch after high-voltage power-on is within 8V, and close its main positive contactor after a 500ms interval. If the voltage difference between the remaining two power battery branches and the first power battery branch is within 8V, close only the main negative contactor of the two power battery branches. During the load discharge process, when the voltage of the first power battery branch drops to a voltage difference of less than 5V with either of the two power battery branches and stabilizes for 3s, close the main positive contactor of the power battery branch whose voltage difference is stable at less than 5V, and send a 2 / 3 vehicle maximum load power request to the BMS master control after a 5s delay. Continue in this manner until all power battery branches have achieved high-voltage power-on in this process. After the last power battery branch has been high-voltage powered on, send a vehicle rated maximum load power request 5s later to supply power to the vehicle load.

[0069] The power battery system of this application, through reasonable power-on logic, avoids damage to related components, which helps to improve the reliability and safety of vehicle operation.

[0070] In some implementations, the first battery management unit is configured to: in response to detecting that the vehicle charging plug is connected to the charger and the insulation detection function of all third battery management units is turned off, determine whether all insulation detection results are qualified; if all insulation detection results are qualified, control multiple contactors in the vehicle combiner cabinet to close sequentially according to a second preset order; based on all received key data, determine the key data with the lowest data value as the second key data, and designate the power battery branch that sends the second key data as the second power battery branch; send a control command to the second power battery branch to control the second power battery branch to perform high-voltage power-on; based on the second power battery branch after high-voltage power-on, send control commands sequentially to the remaining power battery branches to perform high-voltage power-on, so as to charge all battery boxes and monitor whether they have reached the charging cut-off condition; in response to the presence of a battery box that has reached the charging cut-off condition, stop charging all battery boxes and send a charging end command to the charger.

[0071] In some implementations, after the charging plug is connected to the charger, the BMS inside the battery pack receives power and performs a self-test. If the self-test is successful, it establishes a handshake with the charger and begins charging. The charging logic is explained using a three-car train energy storage vehicle as an example:

[0072] (1) Close the charging negative contactor and charging positive contactor in the vehicle combiner cabinet in sequence according to the order of negative first and positive and with an interval of 500ms (i.e. the second preset order);

[0073] (2) After all the contactors in the discharge circuit of the vehicle combiner cabinet are closed for 1 second, the power battery branch with the lowest total voltage value (i.e., the second power battery branch) is selected to precharge the capacitor at the load point of the vehicle according to the total voltage value sent by all power battery branches. A control command is sent to the second power battery branch to close its internal main negative contactor. After an interval of 500ms, its internal pre-charging contactor is closed to start pre-charging. When the voltage sensor in the second power battery branch detects that the load terminal voltage rises to a preset proportion of the total voltage of the second power battery branch, such as 90%, the main positive contactor inside the second power battery branch is closed. After a delay of 5s, its internal pre-charging contactor is opened, and a preset charging current request is sent to the BMS master control to complete the control of the high voltage power-on of the second power battery branch. The preset charging current request is a 0.1C (rated capacity of a single cell) charging current request.

[0074] (3) After pre-charging, close the main negative contactor of the remaining power battery branches whose voltage difference with the second power battery branch after high-voltage power-on is within 8V, and close its main positive contactor after a 500ms interval. If the voltage difference between the remaining two power battery branches and the second power battery branch is within 8V, close only the main negative contactor of the two power battery branches. During the charging process, when the voltage of the second power battery branch drops to a voltage difference of less than 5V with either of the two power battery branches and stabilizes for 3s, close the main positive contactor of the power battery branch whose voltage difference is stable at less than 5V, and send a preset charging current request to the BMS master control after a 5s delay. Continue in this manner until all power battery branches are high-voltage powered on in this process. After the last power battery branch is high-voltage powered on, send a vehicle rated maximum charging current request 5s later to charge all battery boxes.

[0075] In some implementations, after all battery boxes have started charging, the single-gun charging voltage is controlled according to the highest voltage of the individual cell and the current is controlled according to the value specified in the charging control process of the single cluster power battery branch. Dual-gun charging follows the following logic:

[0076] Step 1: After the high voltage is applied, continuously send the charging permission command and send the maximum allowable charging current and voltage of 400A / (3.5×n)V. When the maximum battery box voltage is ≥3.5V, proceed to the next step.

[0077] Step 2: Send the maximum allowable charging current and voltage of 250A / (3.5×n)V. If the maximum battery box voltage is ≥3.5V, proceed to the next step.

[0078] Step 3: Send the maximum allowable charging current and voltage of 125A / (3.5×n)V. If the maximum battery box voltage is ≥3.5V, proceed to the next step.

[0079] Step 4: Send the maximum allowable charging current and voltage of 60A / (3.5×n)V. If the maximum battery box voltage is ≥3.5V, proceed to the next step.

[0080] Step 5: Send the maximum allowable charging current and voltage of 30A / (3.5×n)V. When the maximum battery box voltage is ≥3.5V or the charging current drops to 25A (i.e., the charging cutoff condition is met), stop sending the "allow charging command" and the charging ends.

[0081] When all power battery branches are charging simultaneously, charging of all battery boxes will stop once any power battery branch reaches the charging cutoff condition. After charging is complete, a charging end command is sent to the charger. Upon receiving the charging end command, the charger will stop high-voltage output and disconnect the 24V control power supply (if feasible), after which the charging plug can be removed.

[0082] The power battery system of this application, through reasonable charging logic, avoids damage to related components, which helps to improve the reliability and safety of vehicle operation.

[0083] In some implementations, the first battery management unit is configured to: in response to the high-voltage power-off button being triggered, sequentially control each contactor in the vehicle combiner cabinet to disconnect in a third preset order, and based on a preset delay, sequentially control all contactors in all power battery branches to disconnect in a fourth preset order, so as to stop supplying power to the vehicle load.

[0084] In some implementations, a two-stage power-off mode is used: high-voltage power-off and low-voltage power-off. During high-voltage power-off, the vehicle load output is first stopped. Then, the high-voltage power-off button in the driver's cab is triggered. The BMS master control sequentially disconnects the main positive and negative contactors in the vehicle's combiner cabinet according to a positive-to-negative logic with 300-second intervals (i.e., the third preset sequence). After a 3-second delay, it sequentially disconnects the main positive and negative contactors in multiple power battery branches according to the same logic with 300-second intervals (i.e., the fourth preset sequence), thus completing the high-voltage power-off and stopping power supply to the vehicle load. During low-voltage power-off, triggering the battery disconnect button in the driver's cab disconnects the 24V power to the entire vehicle, successfully completing the voltage power-off.

[0085] The power battery system of this application fully considers factors such as avoiding power-off under load to maintain the consistency of individual battery cells, thereby avoiding damage to related components, improving the reliability and safety of vehicle operation, and increasing operational efficiency.

[0086] In some implementations, the third battery management unit is further configured to disconnect the contactor in the corresponding power battery branch in response to a loss of communication with the second battery management unit or the detection of a corresponding battery box fault.

[0087] In some implementations, when a serious fault occurs in the battery box during the operation of the power battery system, such as overcurrent, overvoltage, undervoltage, or overtemperature, which would cause the main contactor to be disconnected and affect safety, the BMS slave controller in the battery box immediately disconnects the main positive and main negative contactors of the power battery branch where the battery box is located and sends a derating operation request to the BMS master controller. When the BMS slave controller in the battery box loses communication with the BMS master controller connected to it during the operation of the power battery system, the BMS master controller sends a request for the allowed charging and discharging power of the remaining power battery branches to charge and discharge the remaining power battery branches other than its own. Simultaneously, the BMS slave controller takes over the monitoring of the disconnected power battery branch and, after a preset time after the communication failure, such as 5 seconds after the failure, disconnects the main positive and main negative contactors of the disconnected power battery branch. When the power battery system is operating and a communication failure or disconnection occurs between the BMS master controller and the TCMS system, the power battery system maintains normal output until the vehicle returns to the depot.

[0088] In some implementations, the fault alarm level is divided into three levels, from minor to serious, and the fault condition thresholds are shown in Table 1.

[0089] Table 1

[0090]

[0091]

[0092]

[0093]

[0094]

[0095] This application, through a rationally designed power battery system, enables timely disconnection of the fault point to prevent damage to related equipment in the event of a failure of the main positive contactor or the main negative contactor in the battery box of any power battery branch. The system then uses the battery boxes of other power battery branches to take over the work, achieving fault redundancy and ensuring the DC600V power supply to the entire train. This prevents the entire train from being unable to operate due to a lack of DC600V power supply.

[0096] By comprehensively collecting real-time key data from multiple power battery branches, the vehicle combiner cabinet generates precise control commands based on the key data, which are then distributed to multiple power battery branches through the high-voltage box. This allows for flexible adjustment of the working status of each power battery branch, timely detection and control of fault conditions.

[0097] In some implementations, the power battery system also includes a fire suppression module that is connected one-to-one with multiple power battery branches. The fire suppression module includes multiple sensors configured to monitor the fire situation of the corresponding power battery branch and trigger a fire warning of the corresponding level.

[0098] In some implementations, the sensors in the fire suppression module include a CO (carbon monoxide) sensor, a smoke sensor, and a temperature sensor. The fire suppression module has a tiered alarm function, which corresponds to four stages in the development of a power battery system fire: the incubation period, the warning period, the alarm period, and the open flame period. The tiered alarm logic is as follows:

[0099] (1) When the fire is in the incubation period, a Level 1 warning is triggered. The Level 1 warning is for internal use within the power battery system and is not reported externally.

[0100] (2) When a high-sensitivity CO sensor detects an abnormality in CO or discovers an electrolyte leak, the fire situation is in the early warning period, triggering a level II early warning;

[0101] (3) When multiple sensors make a combined judgment of an anomaly, such as CO sensor, smoke sensor and temperature sensor, the fire situation is in the alarm period and a level 3 warning is triggered;

[0102] (4) Under the premise of Level II and Level III warnings, when the temperature sensor detects an abnormal temperature and there is a significant upward trend, the fire situation is in the open flame stage, triggering a Level IV warning.

[0103] In addition, temperature can also be used as a single condition to monitor fire conditions. In this case, the logic for multiple alarm levels is as follows:

[0104] (1) When the temperature sensor detects that the ambient temperature of the battery box is above 70°C, a level 2 warning is triggered;

[0105] (2) When the temperature sensor detects that the ambient temperature of the battery box is above 80°C, a level 3 warning is triggered;

[0106] (3) When the temperature sensor detects that the ambient temperature of the battery box is above 90°C, a level 4 warning is triggered.

[0107] When a Level 4 warning is reached, the BMS central control sends a fire extinguishing command to the fire suppression module to trigger the fire suppression system. The fire suppression module can also perform real-time self-checks. If a functional module malfunctions, it reports the issue to the higher-level equipment via a serial communication protocol (Controller Area Network, CAN) for repair and maintenance.

[0108] The power battery system of this application enables timely early warning of fire by real-time monitoring of the power battery branch through sensors. Furthermore, the hierarchical alarm control logic for fire protection of the power battery system can significantly reduce the safety hazards of the power battery system and solve the problems of imperfect fire control logic, easy failure to report, false alarm, and low safety in related technologies.

[0109] According to another aspect of this application, as shown in FIG5, an embodiment of this application also provides a control method applied to the above-mentioned power battery system, the method comprising:

[0110] Step S100: In response to detecting that the battery charging button is triggered or detecting that the vehicle charging plug is connected to the charger, acquire key data in all power battery branches.

[0111] Step S200: All key data are sent to the vehicle combiner box through multiple high-voltage boxes, so that the vehicle combiner box can generate control commands based on all key data;

[0112] In step S300, control commands are forwarded from multiple high-voltage boxes to multiple power battery branches that are connected one-to-one with the multiple high-voltage boxes, so as to control all power battery branches to charge or supply power to the vehicle load.

[0113] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium for the program can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc. The embodiments of the computer program described above can achieve the same or similar effects as any of the corresponding foregoing method embodiments.

[0114] Those skilled in the art will also understand that the various exemplary logic blocks, modules, circuits, and algorithm steps described in conjunction with the disclosure herein can be implemented as electronic hardware, computer software, or a combination of both. To illustrate this interchangeability between hardware and software, the functionality of various illustrative components, blocks, modules, circuits, and steps has been generally described. Whether this functionality is implemented as software or as hardware depends on the application and the design constraints imposed on the system as a whole. Those skilled in the art can implement the functionality in various ways for each application, but such implementation decisions should not be construed as departing from the scope of the embodiments disclosed in this application.

[0115] The above are exemplary embodiments disclosed in this application. However, it should be noted that various changes and modifications can be made without departing from the scope of the embodiments disclosed in this application as defined by the claims. The functions, steps, and / or actions of the methods according to the disclosed embodiments described herein do not need to be performed in any particular order. The sequence numbers of the embodiments disclosed in this application are merely for descriptive purposes and do not represent the superiority or inferiority of the embodiments. Furthermore, although the elements disclosed in the embodiments of this application may be described or claimed individually, they may be understood as multiple unless explicitly limited to a singular number.

[0116] It should be understood that, as used herein, the singular form “a” is intended to include the plural form as well, unless the context clearly supports an exception. It should also be understood that, as used herein, “and / or” refers to any and all possible combinations of one or more of the associated listed items.

[0117] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the disclosure of the embodiments of this application (including the claims) is limited to these examples; under the concept of the embodiments of this application, the technical features of the above embodiments or different embodiments can also be combined, and there are many other variations of different aspects of the embodiments of this application as described above, which are not provided in detail for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of the embodiments of this application.

Claims

1. A power battery system, applied to multi-pack energy storage vehicles, comprising: Multiple power battery branches connected in parallel, wherein the power battery branches are configured to monitor and transmit key data; Multiple high-voltage boxes, each connected to a corresponding branch of the power battery; and A vehicle combiner cabinet, which is connected to all the high-voltage boxes, is configured to generate control commands based on the key data; The multiple high-voltage boxes are configured to forward all the key data to the vehicle combiner cabinet and forward the control commands to the multiple power battery branches connected to them one by one, so as to control the multiple power battery branches to supply power to the vehicle load.

2. The power battery system according to claim 1, wherein, Each of the power battery branches includes multiple battery boxes connected in series, the battery boxes being configured to supply power to the vehicle load.

3. The power battery system according to claim 2, wherein, The vehicle combiner cabinet includes a first battery management unit, each high-voltage box includes a second battery management unit, and each battery box includes a third battery management unit; The first battery management unit is communicatively connected to all the second battery management units, so that the multiple high-voltage boxes forward the key data sent by the multiple power battery branches corresponding to them to the vehicle combiner cabinet. The second battery management unit is communicatively connected to the corresponding third battery management unit, so that the plurality of high-voltage boxes forward the control commands to the plurality of power battery branches that are connected one-to-one with the plurality of high-voltage boxes.

4. The power battery system according to claim 3, wherein, The third battery management unit is configured as follows: In response to the detection that the battery charging button is triggered or the detection that the vehicle charging plug is connected to the charger, the insulation detection function is activated to obtain the insulation detection result of the corresponding battery box.

5. The power battery system according to claim 4, wherein, The first battery management unit is configured as follows: In response to the detection that the battery input button is triggered and the insulation detection function of all the third battery management units is turned off, it is determined whether all the insulation detection results are qualified; In response to all the insulation test results being qualified, the multiple contactors in the vehicle combiner cabinet are controlled to close sequentially according to a first preset order; Based on all the received key data, the key data with the highest value is determined as the first key data, and the power battery branch that sends the first key data is designated as the first power battery branch. Send the control command to the first power battery branch to control the first power battery branch to be powered on at high voltage. Based on the first power battery branch after high-voltage power-on, the control command is sent sequentially to the remaining power battery branches to perform high-voltage power-on in order to supply power to the vehicle load.

6. The power battery system according to claim 4, wherein, The first battery management unit is configured as follows: In response to detecting that the vehicle charging plug is connected to the charger and that the insulation detection function of all the third battery management units is turned off, it is determined whether all the insulation detection results are qualified; In response to all the insulation test results being qualified, the multiple contactors in the vehicle combiner cabinet are controlled to close sequentially according to the second preset order; Based on all the received key data, the key data with the lowest value is determined as the second key data, and the power battery branch that sends the second key data is designated as the second power battery branch. Send the control command to the second power battery branch to control the second power battery branch to perform high-voltage power-on; Based on the second power battery branch after high voltage power-on, the control command is sent to the remaining power battery branches in sequence to perform high voltage power-on, so as to charge all the battery boxes and monitor whether they have reached the charging cut-off condition. In response to the presence of one of the battery boxes reaching the charging cutoff condition, charging of all the battery boxes is stopped, and a charging end command is sent to the charger.

7. The power battery system according to claim 5, wherein, The first battery management unit is configured as follows: In response to the high-voltage power-off button being triggered, multiple contactors in the vehicle combiner cabinet are controlled to disconnect in a third preset order, and based on a preset delay, all contactors in all power battery branches are controlled to disconnect in a fourth preset order to stop power supply to the vehicle load.

8. The power battery system according to claim 3, wherein, The third battery management unit is also configured to: In response to a loss of communication with the second battery management unit or the detection of a corresponding battery box fault, the contactor in the corresponding power battery branch is disconnected.

9. The power battery system according to claim 1 further includes multiple fire-fighting modules, which are connected one-to-one with the multiple power battery branches. Each fire-fighting module includes multiple sensors configured to monitor the fire situation of the corresponding power battery branch and trigger a fire warning of the corresponding level to the fire situation.

10. A control method applied to a power battery system as described in any one of claims 1-9, comprising: In response to the detection that the battery charging button is triggered or the detection that the vehicle charging plug is connected to the charger, key data in all power battery branches are acquired. All the key data are sent to the vehicle combiner box through multiple high-voltage boxes, so that the vehicle combiner box can generate control commands based on all the key data; The control commands are forwarded through the multiple high-voltage boxes to the multiple power battery branches that are connected one-to-one with the multiple high-voltage boxes, so as to control all the power battery branches to charge or supply power to the vehicle load.

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