Power battery system and control method

Abstract

The invention relates to the technical field of batteries, and discloses a power battery system and a control method. The system comprises a plurality of power battery branches which are connected in parallel and are used for monitoring and sending key data; the high-voltage boxes are connected with the power battery branches in a one-to-one correspondence manner; the whole vehicle confluence cabinet is connected with all the high-voltage boxes and is used for generating a control instruction according to the key data; wherein the high-voltage box is used for forwarding all key data to the whole vehicle confluence cabinet and forwarding control instructions to the power battery branches so as to control the power battery branches to supply power to the whole vehicle load. According to the scheme, the problem that the whole vehicle loses high-voltage power supply and cannot run normally due to the fact that the fault battery pack cannot be independently controlled and isolated in the fault process of the power battery system is solved, the fire control logic is perfected, and the operation efficiency and reliability of the vehicle are improved.

Description

Technical Field

[0001] The present invention relates to the field of battery technology, and in particular to a power battery system and a control method. Background Art

[0002] At present, multi-unit energy storage vehicles have become an emerging means of transportation in urban rail transit. The power battery system is the power source of this vehicle, and its control technology is crucial to the reliability and safety of the system.

[0003] In recent years, with the continuous development of control technology, power battery systems have achieved faster and more accurate monitoring and response in dealing with abnormal conditions such as overcharging, over-discharging, short circuit, high temperature, etc. of battery packs and battery cells. However, the power battery system fault redundancy capability in related technologies is weak, and there is a problem that the consistency of battery cells cannot be guaranteed when powering on, off, and charging. When a partial fault occurs, it is impossible to control the faulty part alone, which can easily lead to the failure of the entire power battery system and the inability of the vehicle to operate.

[0004] Therefore, there is an urgent need for a reasonably designed power battery system that can reasonably control the working state of the power battery system under power battery system failure conditions, maximize the system's operating functions in the event of a system failure, reduce the impact on vehicle operation, and thus improve vehicle operating efficiency and reliability. Summary of the invention

[0005] In view of this, the present invention proposes a power battery system and control method, which solves the problem that the faulty battery pack cannot be individually controlled and isolated during a power battery system failure, causing the entire vehicle to lose high-voltage power supply and be unable to drive normally, improves the fire control logic, and improves the vehicle's operating efficiency and reliability.

[0006] Based on the above purpose, an embodiment of the present invention provides a power battery system, which specifically includes:

[0007] Several power battery branches connected in parallel to monitor and send key data;

[0008] A high-voltage box connected one-to-one with each of the power battery branches; and

[0009] A vehicle combiner cabinet connected to all the high-voltage boxes, used to generate control instructions according to the key data;

[0010] The high-voltage box is used to forward all the key data to the vehicle combiner cabinet, and forward the control instructions to each power battery branch respectively, so as to control each power battery branch to supply power to the vehicle load.

[0011] In some embodiments, the power battery branch further includes a plurality of battery boxes connected in series for power supply.

[0012] In some embodiments, 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;

[0013] The first battery management unit is communicatively connected with the second battery management unit so that the high-voltage box forwards each of the key data to the vehicle combiner cabinet;

[0014] The second battery management unit is communicatively connected with the corresponding third battery management unit so that the high-voltage box forwards the control instruction to each of the power battery branches respectively.

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

[0016] In response to detecting that a battery input button is triggered or detecting that a vehicle charging plug is connected to a charger, an insulation detection function is turned on to obtain an insulation detection result of the battery box.

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

[0018] In response to detecting that the battery input button is triggered and each of the insulation detection functions is turned off, determining whether all the insulation detection results are qualified;

[0019] If all the insulation test results are qualified, the contactors in the vehicle combiner cabinet are controlled to close in sequence according to a first preset order;

[0020] According to all the received key data, determine the key data with the highest data value as the first key data, and use the power battery branch that sends the first key data as the first power battery branch;

[0021] Sending the control instruction 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-up, the control instruction is sent to the remaining power battery branches in sequence to perform high-voltage power-up, so as to supply power to the whole vehicle load.

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

[0024] In response to detecting that the vehicle charging plug is connected to the charger and each of the insulation detection functions is turned off, determining whether all the insulation detection results are qualified;

[0025] If all the insulation test results are qualified, the contactors in the vehicle combiner cabinet are controlled to close in sequence according to a second preset order;

[0026] According to all the received key data, determine the key data with the lowest data value as the second key data, and use the power battery branch that sends the second key data as the second power battery branch;

[0027] Sending the control instruction to the second power battery branch to control the second power battery branch to be powered on at high voltage;

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

[0029] In response to one of the battery boxes reaching a charging cut-off condition, charging of all the battery boxes is stopped, and a charging end instruction is sent to the charger.

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

[0031] In response to the high-voltage power-off button being triggered, the contactors in the vehicle combiner cabinet are controlled to be disconnected in sequence according to the third preset order, and based on the preset delay, the contactors in all the power battery branches are controlled to be disconnected in sequence according to the fourth preset order to stop supplying power 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 a detection of a corresponding battery box failure, a contactor in the corresponding power battery branch is disconnected.

[0034] In some embodiments, a fire protection module is further included which is connected to each of the power battery branches in a one-to-one correspondence. The fire protection module includes a plurality of sensors for monitoring the fire conditions of the corresponding power battery branches and triggering a fire warning of a level corresponding to the fire conditions.

[0035] Another aspect of the embodiment of the present invention further provides a control method, which is applied to the power battery system as described above, and the method includes:

[0036] In response to detecting that a battery input button is triggered or detecting that a vehicle charging plug is connected to a charger, key data in all power battery branches are obtained;

[0037] Send all the key data to the vehicle combiner box through the high-voltage box, so that the vehicle combiner box generates a control instruction based on all the key data;

[0038] The control instructions are forwarded to each of the power battery branches respectively through the high-voltage box to control all the power battery branches to charge or supply power to the entire vehicle load.

[0039] The present invention has at least the following beneficial technical effects:

[0040] (1) The power battery system of the present invention has a more clear structure through the layered architecture of the power battery branch, the high-voltage box and the whole vehicle combiner cabinet. The modular design of the power battery branch is combined with the distributed design of the high-voltage box to achieve the fault isolation function, so that the power battery branch is easy to maintain and replace independently, reducing the impact of single-point failure on the overall operation. After a single power battery branch fails, the output of this battery branch can be cut off, and other power battery branches can supply power to the vehicle normally, thereby realizing the reasonable control of the working state of the power battery system under the power battery system failure condition, and can maximize the system operation function under the system failure condition, reduce the impact on the vehicle operation, and thus improve the vehicle operation efficiency and reliability;

[0041] (2) Through the comprehensive collection of real-time key data from each power battery branch, the vehicle's junction box generates accurate control instructions based on the key data, which are distributed to each power battery branch through the high-voltage box. This allows the working status of each power battery branch to be flexibly adjusted, and fault conditions to be discovered and controlled in a timely manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other embodiments can be obtained based on these drawings without paying creative work.

[0043] Figure 1 A topological diagram of a power battery system for a multi-group energy storage vehicle in the related art;

[0044] Figure 2 A schematic diagram of an embodiment of a power battery system provided by the present invention;

[0045] Figure 3 A topological diagram of an embodiment of a power battery system provided by the present invention;

[0046] Figure 4 A schematic diagram of an embodiment of a BMS architecture in a power battery system provided by the present invention;

[0047] Figure 5 A block diagram of an embodiment of a control method provided by the present invention. DETAILED DESCRIPTION

[0048] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0049] It should be noted that all expressions using "first" and "second" in the embodiments of the present invention are for distinguishing two non-identical entities with the same name or non-identical parameters. It can be seen that "first" and "second" are only for the convenience of expression and should not be understood as limitations on the embodiments of the present invention. The subsequent embodiments will not explain this one by one.

[0050] like Figure 1 The figure shows a power battery system for a multi-unit energy storage vehicle in the related art, which adopts a centralized power supply method for the train load. Taking a three-unit vehicle as an example, each unit power battery is uniformly connected to the high-voltage box through the high-voltage bus, and then the high-voltage box is used to centrally supply power to each load of the vehicle. The charging process is similar, with the ground charger outputting to the high-voltage box, and then the high-voltage box uniformly charging each battery unit. Each battery unit in the above scheme cannot be controlled by its own independent contactor, but 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: during operation, if there is a serious fault such as overcurrent, overvoltage, undervoltage and overtemperature of the entire system, which cuts off the main contactor and affects safety, or there is a communication failure or loss of connection between the battery management unit (BMS) and the entire vehicle, or there is a single battery branch, battery box or battery monomer overcurrent, overvoltage, undervoltage and overtemperature, etc., the whole power battery system is cut off by disconnecting the main positive contactor and the main negative contactor.

[0051] However, the above fault control logic has the following shortcomings:

[0052] 1. Single cluster fault cannot be isolated. The power battery system lacks the ability to independently isolate a single cluster of power battery branches, resulting in the need to disconnect the main positive and negative contactors of the entire system when a cluster of power battery branches or battery cells fails. This not only causes the entire vehicle to lose high-voltage power supply, but also makes the vehicle unable to drive normally.

[0053] 2. The total output lacks redundant configuration. The main positive and negative contactors of the power battery system do not have a redundant design. Once the contactor fails, such as failing to close or disconnect, the entire vehicle will completely lose high-voltage power supply or fail to complete the high-voltage power-off operation. This design causes vehicle operation interruption, affects passenger comfort, and may cause failure or damage to related equipment, further increasing maintenance costs and safety risks.

[0054] 3. The control logic is too simple. The control logic of the power battery system is relatively simple, and the on-load and off-load operations cannot be accurately managed, which may cause the consistency of the battery cells to be out of balance, thereby causing damage to related devices.

[0055] 4. Insufficient fire control logic. The fire control logic of the power battery system is imperfect and prone to missed or false alarms, which weakens the safety of the system. Especially in emergency situations, the inability to accurately perceive and handle fire risks may lead to delayed handling or false triggering of protective measures, further threatening the safety of the vehicle and passengers.

[0056] Safety and reliability are the core concerns of the control technology of the power battery system of multi-unit energy storage vehicles. In order to solve the above-mentioned defects of the power battery system in the related technology. The reasonable design of the switching sequence of the control devices and the start-up sequence of the loads in the present invention plays a vital role in the safe and reliable operation of the power battery system. At the same time, electrical fault redundancy technology is an important means to improve the reliability and availability of the system. This technology can immediately replace the operation when the main component or main system fails by adding auxiliary components, equipment or systems to ensure the normal operation of the system. The present invention uses electrical fault redundancy technology in the control of the power battery system, which greatly improves the safety and reliability of the power battery system and avoids the situation where the entire power battery system fails when a partial fault occurs, resulting in the inability to operate the vehicle.

[0057] Based on the above objectives, the first aspect of the embodiments of the present invention provides a power battery system. Figure 2 As shown, the power battery system includes:

[0058] A plurality of power battery branches 1 connected in parallel with each other, used for monitoring and sending key data;

[0059] A high-voltage box 2 connected to each power battery branch 1 in a one-to-one correspondence; and

[0060] The vehicle combiner cabinet 3 connected to all high-voltage boxes 2 is used to generate control instructions based on key data;

[0061] The high-voltage box 2 is used to forward all key data to the vehicle combiner cabinet 3, and forward control instructions to each power battery branch 1 respectively, so as to control each power battery branch 1 to supply power to the vehicle load.

[0062] In some embodiments, Figure 3 As shown, taking a three-group energy storage vehicle as an example, the power battery system of the present invention adopts three power battery branches connected in parallel, and each power battery branch is composed of a number of battery boxes connected in series, for example Figure 3The vehicle consists of three battery boxes connected in series, and each power battery branch is located in a different group of the vehicle. The charging and discharging high-voltage busbars of each power battery branch are output by the corresponding high-voltage boxes to the vehicle junction box for grid connection, and then supply power to the vehicle load. The battery management unit exists in the vehicle junction box, the high-voltage box, and each battery box of each power battery branch. Its architecture from high to low is the BMS master control of the vehicle junction box, the BMS master control of the high-voltage box, and the BMS slave control of the battery box, such as Figure 4 As shown. At the same time, each cluster of power battery branches is also equipped with a fire protection system, and its operation is controlled by the BMS master control in the vehicle combiner cabinet. The power battery branch is connected to the high-voltage box corresponding to the branch through the high-voltage bus to realize external discharge and self-charging. At the same time, the power battery branch communicates with the BMS master control in the high-voltage box, and feeds back key data of the power battery branch and the battery box monomer to the BMS master control, including temperature, voltage, current, etc. The high-voltage box controls the charging and discharging of the corresponding power battery branch by turning on and off the contactor in the box. The vehicle combiner cabinet is connected to the high-voltage box through the high-voltage bus, and controls the charging and discharging of all power battery branches by turning on and off the contactor in the cabinet. The BMS master control in the vehicle combiner cabinet communicates with the BMS master control in the high-voltage box to receive key data, and performs logical operations based on the key data to issue control instructions, and also communicates with the TCMS (Train Control and Management System) system.

[0063] The power battery system of the present invention makes the power battery system structure clearer through the layered architecture of the power battery branch, the high-voltage box and the whole vehicle junction box. The modular design of the power battery branch is combined with the distributed design of the high-voltage box to realize the fault isolation function, so that the power battery branch is easy to maintain and replace independently, reducing the impact of single-point failure on the overall operation. After a single power battery branch fails, the output of this battery branch can be cut off, and other power battery branches can supply power to the vehicle normally, thereby realizing reasonable control of the working state of the power battery system under the power battery system failure condition, and can maximize the system operation function in the case of system failure, reduce the impact on vehicle operation, and thus improve vehicle operation efficiency and reliability.

[0064] In some embodiments, the power battery branch further includes a plurality of battery boxes connected in series for power supply.

[0065] In some embodiments, the vehicle combiner cabinet also includes a first battery management unit, the high-voltage box also includes a second battery management unit, and the battery box also 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 each 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 the control instructions to each power battery branch respectively.

[0066] In some embodiments, the first battery management unit is a BMS master control, the second battery management unit is a BMS master control, and the third battery management unit is a BMS slave control. The BMS master control of the high-voltage box communicates with each BMS slave control of the battery branch and the BMS master control of the vehicle combiner cabinet, receives control instructions issued by the BMS master control, and forwards the control instructions to the BMS slave control, and at the same time receives key data fed back by the BMS slave control, and feeds the key data back to the BMS master control, playing a role of connecting the upper and lower parts.

[0067] In some embodiments, the third battery management unit is configured to: in response to detecting that the battery input button is triggered or detecting that the vehicle charging plug is connected to the charger, start the insulation detection function to obtain the insulation detection result of the battery box.

[0068] In some embodiments, the first battery management unit is configured as follows: in response to detecting that the battery input button is triggered and each insulation detection function is turned off, determining whether all insulation detection results are qualified; if all insulation detection results are qualified, controlling each contactor in the vehicle junction box to close in sequence according to a first preset order; based on all the key data received, determining the key data with the highest data value as the first key data, and using the power battery branch that sends the first key data as the first power battery branch; sending a control instruction to the first power battery branch to control the first power battery branch to power on at high voltage; based on the first power battery branch after high voltage power-on, sending control instructions to the remaining power battery branches in sequence to power on at high voltage to supply power to the entire vehicle load.

[0069] In some embodiments, after pressing the battery input button, 24V low-voltage electricity is applied, the whole vehicle is activated and powered on, and the BMS performs self-test from empty power. During the self-test, insulation detection of each power battery branch is carried out. The insulation test is completed before all contactors in the high-voltage box corresponding to each power battery branch are closed. The contactors in each high-voltage box can be closed only after the insulation test is qualified and the insulation test function is turned off. When all power battery branches are self-checked and correct, the high-voltage power-on step begins. Taking a three-unit energy storage vehicle as an example, the power-on logic is explained:

[0070] (1) The BMS master control controls the closing of each contactor in the vehicle combiner cabinet according to the first preset sequence. Specifically, the discharge total negative contactor in the vehicle combiner cabinet is controlled to close first, and then the electric drive contactor and the power supply contactor are controlled to close at the same time after an interval of 500ms;

[0071] (2) After the contactors of the discharge circuit in the whole vehicle junction box are closed for 1s, the power battery branch with the highest total voltage value (i.e., the first power battery branch) is selected according to the total voltage value sent by all power battery branches to pre-charge the load point capacitor of the whole vehicle. Specifically, a control instruction 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 exceeding 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 disconnected, and the preset vehicle maximum load power request is sent to the BMS master control to complete the control of the high-voltage power-on of the first power battery branch; wherein the preset vehicle maximum load power request is 1 / 3 of the vehicle maximum load power request;

[0072] (3) After the pre-charging is completed, the main negative contactors of the remaining power battery branches whose voltage difference with the first power battery branch after high-voltage power-on are closed, and their main positive contactors are closed after an interval of 500ms. If the voltage difference between the remaining two power battery branches and the first power battery branch is within 8V, only the main negative contactors of the two power battery branches are closed. During the waiting load discharge process, when the voltage of the first power battery branch drops to a voltage difference of less than 5V with any of the two power battery branches and stabilizes for 3s, the main positive contactor of the power battery branch with a stable voltage difference of less than 5V is closed, and after a delay of 5s, a 2 / 3 vehicle maximum load power request is sent to the BMS master control. This process is repeated until all power battery branches are powered on at high voltage in this process. When the last power battery branch is powered on at high voltage, a vehicle rated maximum load power request is sent 5s after the high-voltage power-on is completed to power the vehicle load.

[0073] The power battery system of the present invention avoids damage to related devices through reasonable power-on logic, which is beneficial to improving the reliability and safety of vehicle operation.

[0074] In some embodiments, the first battery management unit is configured as follows: in response to detecting that the vehicle charging plug is connected to the charger and each insulation detection function is turned off, determining whether all insulation detection results are qualified; if all insulation detection results are qualified, controlling each contactor in the vehicle junction box to close in sequence according to a second preset order; based on all the key data received, determining the key data with the lowest data value as the second key data, and using the power battery branch that sends the second key data as the second power battery branch; sending a control instruction to the second power battery branch to control the second power battery branch to power on at high voltage; based on the second power battery branch after high voltage power-on, sending control instructions to the remaining power battery branches in sequence to power on at high voltage, so as to charge all battery boxes and monitor whether they meet the charging cut-off condition; in response to the existence of a battery box that meets the charging cut-off condition, stopping charging of all battery boxes, and sending a charging end instruction to the charger.

[0075] In some embodiments, after the charging plug is connected to the charger, the BMS inside the battery box receives power from the controller to perform self-checking. After the self-check is correct, it confirms the handshake with the charger and starts charging. Taking a three-train energy storage vehicle as an example, the charging logic is explained:

[0076] (1) Close the negative charging contactor and the positive charging contactor in the vehicle combiner cabinet in sequence in the order of negative first and positive later with an interval of 500ms (i.e., the second preset order);

[0077] (2) After the contactors of the discharge circuit in the whole vehicle junction box are closed for 1s, the power battery branch with the lowest total voltage value (i.e., the second power battery branch) is selected according to the total voltage value sent by all power battery branches to pre-charge the load point capacitor of the whole vehicle. Specifically, a control instruction is sent to the second power battery branch to close its internal main negative contactor, and 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 exceeding the total voltage of the second power battery branch, such as 90%, the main positive contactor inside the second power battery branch is closed, and after a delay of 5s, its internal pre-charging contactor is disconnected, 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; wherein the preset charging current request is a 0.1C (single unit rated capacity) charging current request.

[0078] (3) After the pre-charging is completed, close the main negative contactors of the remaining power battery branches whose voltage difference with the second power battery branch after high-voltage power-on is within 8V, and then close their main positive contactors after an interval of 500ms. If the voltage difference between the remaining two power battery branches and the second power battery branch is within 8V, only the main negative contactors of the two power battery branches are closed. During the waiting charging process, when the voltage of the second power battery branch drops to a voltage difference of less than 5V with any of the two power battery branches and stabilizes for 3s, close the main positive contactor of the power battery branch with a stable voltage difference of less than 5V, and send a preset charging current request to the BMS master control after a delay of 5s. This process is repeated until all power battery branches are powered on with high voltage in this process. When the high-voltage power-on of the last power battery branch is completed, a request for the rated maximum charging current of the vehicle is sent 5s later to charge all battery boxes;

[0079] In some embodiments, after all battery boxes start charging, the single-gun charging voltage is controlled according to the highest voltage of the single cell and the current is controlled according to the specified value in the single-cluster power battery branch charging control process, and the dual-gun charging is controlled according to the following logic:

[0080] Step 1: After the high voltage is powered on, continue to send the charging permission instruction, and send the maximum allowable charging current and voltage of 400A / (3.5×n)V. When the maximum battery box voltage is ≥3.5V, go to the next step;

[0081] Step 2: Send the maximum allowable charging current and voltage of 250A / (3.5×n)V. When the maximum battery box voltage is ≥3.5V, go to the next step;

[0082] Step 3: Send the maximum allowable charging current and voltage of 125A / (3.5×n)V. When the maximum battery box voltage is ≥3.5V, go to the next step;

[0083] Step 4: Send the maximum allowable charging current and voltage of 60A / (3.5×n)V. When the maximum battery box voltage is ≥3.5V, go to the next step;

[0084] 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 is reduced to 25A (i.e., the charging cut-off condition is reached), stop sending the "allow charging instruction" and charging is terminated.

[0085] When all power battery branches are charged at the same time, if any power battery branch reaches the charging cut-off condition, the charging of all battery boxes will be stopped. After the charging is completed, a charging end instruction is sent to the charger. After receiving the charging end instruction, the charger stops the high voltage output and cuts off the 24V control power supply (if feasible), and then the charging plug can be removed.

[0086] The power battery system of the present invention avoids damage to related devices through reasonable charging logic, which is beneficial to improving the reliability and safety of vehicle operation.

[0087] In some embodiments, the first battery management unit is configured to: in response to the high-voltage power-off button being triggered, control the disconnection of each contactor in the vehicle junction box in sequence according to a third preset order, and based on a preset delay, control the disconnection of each contactor in all power battery branches in sequence according to a fourth preset order to stop supplying power to the vehicle load.

[0088] In some embodiments, two power-off modes are used, namely high-voltage power-off and low-voltage power-off. When high-voltage power-off, first stop the vehicle load output, then trigger the high-voltage power-off button in the driver's cab, and the BMS master control disconnects the main positive contactor and the main negative contactor in the vehicle junction box in sequence according to the logic of positive first and negative later and at an interval of 300s (i.e., the third preset sequence), and after a delay of 3s, disconnects the main positive contactor and the main negative contactor in each power battery branch in sequence according to the logic of positive first and negative later and at an interval of 300s (i.e., the fourth preset sequence), thereby completing high-voltage power-off and stopping power supply to the vehicle load. When low-voltage power-off, trigger the battery removal button in the driver's cab to cut off the 24V power of the vehicle, and the voltage power-off is successful.

[0089] The power battery system of the present invention has a power-off logic that fully considers factors such as avoiding power-off under load to maintain the consistency of battery cells, thereby avoiding damage to related devices, improving the reliability and safety of vehicle operation, and improving operational efficiency.

[0090] In some embodiments, the third battery management unit is further configured to: in response to a loss of communication with the second battery management unit or a detection of a corresponding battery box failure, disconnect a contactor in a corresponding power battery branch.

[0091] In some embodiments, when the power battery system is in operation, the battery box has a serious fault such as overcurrent, overvoltage, undervoltage or overtemperature that cuts off its main contactor and affects safety, the BMS slave control in the battery box immediately cuts off the main positive and main negative contactors of the power battery branch where the battery box is located, and sends a derated operation request to the BMS master control. When the power battery system is in operation, the BMS slave control in the battery box loses communication with the BMS master control connected to it, then the BMS master control sends a charge and discharge power request allowed by the remaining power battery branch to charge and discharge through the remaining power battery branch except the power battery branch where it is located. At the same time, the BMS slave control takes over the monitoring of the lost power battery branch, and cuts off the main positive contactor and main negative contactor of the lost power battery branch at a preset time after the communication loss fault occurs, such as 5s after the fault occurs. When the power battery system is in operation, when the BMS master control and the TCMS system have a communication failure or lose connection, the power battery system maintains normal output until the vehicle returns to the warehouse.

[0092] In some implementations, the fault alarm levels are divided into three levels from slight to fault, and the fault condition thresholds are shown in Table 1.

[0093] Table 1

[0094]

[0095]

[0096]

[0097]

[0098]

[0099] The present invention uses a reasonably designed power battery system to achieve timely cutting off of the fault point to avoid damage to related equipment when a main positive contactor or a main negative contactor in a battery box in any power battery branch fails, and replaces the work by battery boxes in other power battery branches to achieve fault redundancy and ensure the DC600V power supply of the entire train, so as to avoid the situation where the equipment cannot work and the vehicle cannot run due to the lack of DC600V power supply of the entire vehicle.

[0100] In some embodiments, a fire protection module is further included which is connected to each power battery branch in a one-to-one correspondence. The fire protection module includes a plurality of sensors for monitoring the fire conditions of the corresponding power battery branches and triggering a fire warning of a level corresponding to the fire conditions.

[0101] In some embodiments, the sensors in the fire protection module include a CO (carbon monoxide) sensor, a smoke sensor, and a temperature sensor. The fire protection module has a graded alarm function, which corresponds to the four stages of the latent period, early warning period, alarm period, and open fire period in the development process of the power battery system fire. The logic of each graded alarm is as follows:

[0102] (1) When the fire situation is in the latent stage, the first-level warning is triggered. The first-level warning is for internal use of the power battery system and is not reported externally;

[0103] (2) When the highly sensitive CO sensor detects an abnormal CO or electrolyte leakage, the fire situation is in the early warning period and triggers the second-level early warning;

[0104] (3) When multiple sensors make composite judgments of abnormality, such as CO sensor, smoke sensor and temperature sensor, the fire situation is in the alarm period, triggering the third-level warning;

[0105] (4) Under the premise of level 2 and level 3 warning, when the temperature sensor detects abnormal temperature with a clear upward trend, the fire situation is in the open flame period and the level 4 warning is triggered.

[0106] In addition, temperature can also be used as a single condition to monitor fire conditions. In this case, the alarm logic for each level is as follows:

[0107] (1) When the temperature sensor detects that the ambient temperature of the battery box is above 70°C, a secondary warning is triggered;

[0108] (2) When the temperature sensor detects that the ambient temperature of the battery box is above 80°C, a level 3 warning is triggered;

[0109] (3) When the temperature sensor detects that the ambient temperature of the battery box is above 90°C, a level 4 warning is triggered.

[0110] When the fourth-level warning is reached, the BMS master control sends a fire extinguishing command to the fire fighting module to trigger the fire fighting device to extinguish the fire. The fire fighting module can also perform real-time self-checking. When a functional module fails, it will report to the upper-level equipment through CAN (Controller Area Network, a serial communication protocol) communication for inspection and maintenance.

[0111] The power battery system of the present invention monitors the power battery branch in real time through sensors to achieve timely early warning of fire, and the hierarchical alarm control logic of the power battery system fire protection can fully reduce the safety hazards of the power battery system, solving the problems of imperfect fire control logic in related technologies, prone to missed reports, false alarms and low safety.

[0112] Based on the same inventive concept, according to another aspect of the present invention, Figure 5 As shown, an embodiment of the present invention further provides a control method, which is applied to the above power battery system, and the method includes:

[0113] Step S100, in response to detecting that the battery input button is triggered or detecting that the vehicle charging plug is connected to the charger, acquiring key data in all power battery branches;

[0114] Step S200, sending all key data to the vehicle combiner box through the high-voltage box, so that the vehicle combiner box generates control instructions based on all key data;

[0115] Step S300, forwarding the control instructions to each power battery branch through the high-voltage box, so as to control all power battery branches to charge or supply power to the vehicle load.

[0116] Finally, it should be noted that a person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, the storage medium of the program can be a disk, an optical disk, a read-only storage memory (ROM) or a random access memory (RAM), etc. The above-mentioned computer program embodiments can achieve the same or similar effects as the corresponding above-mentioned arbitrary method embodiments.

[0117] It will also be appreciated by those skilled in the art that 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 the two. In order to clearly illustrate this interchangeability of hardware and software, a general description has been given to the functions of various schematic components, blocks, modules, circuits and steps. Whether this function is implemented as software or implemented as hardware depends on specific applications and the design constraints imposed on the entire system. Those skilled in the art can implement the function in various ways for each specific application, but this implementation decision should not be interpreted as causing a departure from the disclosed scope of the embodiments of the present invention.

[0118] The above are exemplary embodiments disclosed in the present invention, but it should be noted that various changes and modifications may be made without departing from the scope of the embodiments disclosed in the present invention as defined in the claims. The functions, steps and / or actions of the method claims according to the disclosed embodiments described herein do not need to be performed in any particular order. The serial numbers of the embodiments disclosed in the above embodiments of the present invention are for description only and do not represent the advantages and disadvantages of the embodiments. In addition, although the elements disclosed in the embodiments of the present invention may be described or required in individual form, they may also be understood as multiple unless explicitly limited to the singular.

[0119] It should be understood that, as used herein, the singular forms "a", "an" are intended to include the plural forms 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 including one or more of the associated listed items.

[0120] A person skilled in the art should understand that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope of the disclosure of the embodiments of the present invention (including the claims) is limited to these examples; under the concept of the embodiments of the present invention, the technical features in the above embodiments or different embodiments can also be combined, and there are many other changes in different aspects of the embodiments of the present invention as above, which are not provided in detail for the sake of simplicity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention should be included in the protection scope of the embodiments of the present invention.

Claims

1. A power battery system, characterized in that: Applied to multi-unit energy storage vehicles, including: Several power battery branches connected in parallel to monitor and send key data; A high-voltage box connected one-to-one with each of the power battery branches; and A vehicle combiner cabinet connected to all the high-voltage boxes, used to generate control instructions according to the key data; The high-voltage box is used to forward all the key data to the vehicle combiner cabinet, and forward the control instructions to each power battery branch respectively, so as to control each power battery branch to supply power to the vehicle load.

2. The power battery system according to claim 1, characterized in that: The power battery branch also includes a plurality of battery boxes connected in series for power supply.

3. The power battery system according to claim 2, characterized in that: 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 with the second battery management unit so that the high-voltage box forwards each of the key data to the vehicle combiner cabinet; The second battery management unit is communicatively connected with the corresponding third battery management unit so that the high-voltage box forwards the control instruction to each of the power battery branches respectively.

4. The power battery system according to claim 3, characterized in that: The third battery management unit is configured as follows: In response to detecting that a battery input button is triggered or detecting that a vehicle charging plug is connected to a charger, an insulation detection function is turned on to obtain an insulation detection result of the battery box.

5. The power battery system according to claim 4, characterized in that: The first battery management unit is configured as: In response to detecting that the battery input button is triggered and each of the insulation detection functions is turned off, determining whether all the insulation detection results are qualified; If all the insulation test results are qualified, the contactors in the vehicle combiner cabinet are controlled to close in sequence according to a first preset order; According to all the received key data, determine the key data with the highest data value as the first key data, and use the power battery branch that sends the first key data as the first power battery branch; Sending the control instruction 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-up, the control instruction is sent to the remaining power battery branches in sequence to perform high-voltage power-up, so as to supply power to the whole vehicle load.

6. The power battery system according to claim 4, characterized in that: The first battery management unit is configured as: In response to detecting that the vehicle charging plug is connected to the charger and each of the insulation detection functions is turned off, determining whether all the insulation detection results are qualified; If all the insulation test results are qualified, the contactors in the vehicle combiner cabinet are controlled to close in sequence according to a second preset order; According to all the received key data, determine the key data with the lowest data value as the second key data, and use the power battery branch that sends the second key data as the second power battery branch; Sending the control instruction to the second power battery branch to control the second power battery branch to be powered on at high voltage; Based on the second power battery branch after high voltage power-up, the control instruction is sent to the remaining power battery branches in sequence to perform high voltage power-up, so as to charge all the battery boxes and monitor whether they meet the charging cut-off condition; In response to one of the battery boxes reaching a charging cut-off condition, charging of all the battery boxes is stopped, and a charging end instruction is sent to the charger.

7. The power battery system according to claim 5, characterized in that: The first battery management unit is configured as: In response to the high-voltage power-off button being triggered, the contactors in the vehicle combiner cabinet are controlled to be disconnected in sequence according to the third preset order, and based on the preset delay, the contactors in all the power battery branches are controlled to be disconnected in sequence according to the fourth preset order to stop supplying power to the vehicle load.

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

9. The power battery system according to claim 1, characterized in that: It also includes a fire protection module connected to each of the power battery branches in a one-to-one correspondence. The fire protection module includes a plurality of sensors for monitoring the fire conditions of the corresponding power battery branches and triggering a fire warning of a level corresponding to the fire conditions.

10. A control method, characterized in that: Applied to the power battery system according to any one of claims 1 to 9, the method comprises: In response to detecting that a battery input button is triggered or detecting that a vehicle charging plug is connected to a charger, key data in all power battery branches are obtained; Send all the key data to the vehicle combiner box through the high-voltage box, so that the vehicle combiner box generates a control instruction based on all the key data; The control instructions are forwarded to each of the power battery branches respectively through the high-voltage box to control all the power battery branches to charge or supply power to the entire vehicle load.

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