Intelligent charging control system and method for power battery system and vehicle

Abstract

The invention discloses an intelligent charging control system and method for a power battery system and a vehicle. The intelligent charging control system of the power battery system is used for charging control of a battery system with at least two branches, and the branches are arranged in parallel. Each branch circuit comprises a battery module formed by connecting N battery boxes in series, a charging branch circuit and a heating branch circuit, the positive electrode of each charging branch circuit is connected with a branch circuit switch, the positive electrode of each heating branch circuit is connected with a branch circuit heating switch, and all the heating branch circuits can be controlled by any branch circuit heating switch; the branch switch and the branch heating switch are connected in parallel and then are connected to a charging and discharging positive port of the charging system through the charging and discharging positive switch; the negative electrode of each heating branch is connected to a charging and discharging negative electrode port of the charging system through a charging and discharging negative electrode switch, and the negative electrode of each charging branch is connected with the charging and discharging negative electrode switch through a current sensor. According to the invention, on-off of the switches between the branches can be controlled, and connection and disconnection of different branches are realized.

Description

Technical Field

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

[0002] Multi-branch battery systems are widely used in large electric vehicles such as new energy heavy trucks and buses. They aim to optimize energy management and improve safety by dividing large-capacity battery systems into multiple independently controllable smaller-capacity branches. Due to factors such as differences in internal resistance, temperature, and aging of each battery, circulation is inevitable in this multi-branch battery system. In actual applications, each branch is directly connected in the high-voltage box through a power line, resulting in the existence of circulation. In particular, after DC charging is completed, the branch with a higher capacity will charge the branch with a lower capacity. Since the branches are directly connected in the high-voltage box through a bus, this circulation cannot be eliminated, and there is a risk of overcharging the battery cells in a branch.

[0003] In the technology disclosed in CN114256915A, when each battery branch in a multi-branch high-voltage battery system is equipped with an independent relay, the steps of performing battery charging include: obtaining the state of charge value of each battery branch and the operating mode of the battery management unit; based on the state of charge value of each battery branch and the operating mode of the battery management unit, controlling the on and off state of each relay and the main relay of the multi-branch high-voltage battery system. This invention configures an independent relay and charging interface for each battery branch, so that each battery branch can achieve independent charging management, which can effectively solve the problem of excessive charging current difference of each battery branch, and can make each battery branch fully reach a fully charged state, thereby improving the charging efficiency. However, this invention configures an independent charging interface for each branch, resulting in a waste of hardware resources.

[0004] The existing conventional multi-branch battery system has branches connected in parallel, with a simple high-voltage topology and simple power-on and power-off logic, which can be completed by controlling the main negative, pre-charge, and main positive relays. It can only charge and discharge the branches simultaneously and cannot be controlled independently. After different levels of system faults occur, the three branches will limit power output or stop output at the same time, which cannot meet the needs of charging and discharging. Summary of the invention

[0005] The purpose of the present invention is to overcome the shortcomings and defects of the prior art and provide a power battery system intelligent charging control system and charging control method and vehicle. Based on the power battery system intelligent charging control system and the preset charging control strategy, through the opening and closing control of the charging and discharging switches of each battery branch, it is ensured that each battery branch can be fully charged separately, the capacity of the overall battery system is improved, and the vehicle has sufficient driving range.

[0006] According to a first aspect of the present invention, there is provided an intelligent charging control system for a power battery system, which is used to control the charging of a battery system having at least two branches, wherein the branches are arranged in parallel; each branch comprises a battery module consisting of N battery boxes connected in series, a charging branch and a heating branch, the positive pole of each charging branch is connected to a branch switch, the positive pole of each heating branch is connected to a branch heating switch, and all heating branches can be controlled by any branch heating switch; after the branch switches and branch heating switches are connected in parallel, they are connected to the charging and discharging positive pole port of the charging system through the charging and discharging positive pole switch; the negative pole of each heating branch is connected to the charging and discharging negative pole port of the charging system through the charging and discharging negative pole switch, and the negative pole of each charging branch is connected to the charging and discharging negative pole switch through a current sensor.

[0007] Among them, the charging and discharging positive pole switch includes two parallel charging positive pole switches, one discharging positive pole switch, and one pre-charging switch; the discharging positive pole switch is connected to the positive discharge port of the charging system after being connected in parallel with the pre-charging switch; the two parallel charging positive pole switches are each connected to a positive charging port of the charging system.

[0008] Among them, one end of each current sensor is connected to the negative electrode of the battery module formed by the corresponding series battery box, the other end of the current sensor is connected to a terminal of the maintenance switch MSD, and the other terminal of the maintenance switch MSD is connected to the negative electrode charge and discharge switch.

[0009] The charging and discharging negative pole switch includes a discharging negative pole switch and two parallel charging negative pole switches, the two charging negative pole switches are respectively connected to a charging negative pole port of the charging system, and the discharging negative pole switch is connected to the discharging negative pole port.

[0010] Wherein, the current sensor is a Hall sensor.

[0011] Wherein, the branch switch, branch heating switch, charge and discharge positive switch and charge and discharge negative switch adopt relays.

[0012] Among them, the current sensor, branch switch, branch heating switch, charge and discharge positive switch and charge and discharge negative switch are arranged in the high-voltage box of the vehicle; a battery management system BMS is arranged in the high-voltage box, and the battery management system BMS is connected to the battery monitoring unit CSC inside the battery box through the CAN bus. The battery management system BMS is connected to the vehicle through the CAN bus, and is connected to the charging column for data exchange during charging.

[0013] A second aspect of the present invention provides a power battery system intelligent charging control method, which is implemented based on the power battery system intelligent charging control system; comprising the steps of:

[0014] Step 201, plug in the charging gun to power on and wake up the battery management system BMS;

[0015] Step 202, the BMS obtains the total voltage of each branch and reads the SOC value of each branch;

[0016] Step 203, determine whether there is a battery failure, if yes, go to step 204, otherwise go to step 205;

[0017] Step 204, disconnect charging;

[0018] Step 205, determine whether the total pressure difference between the branches is less than or equal to the set value_1, if yes, execute step 206, if not, execute step 209;

[0019] Step 206, closing the branch switches of all branches;

[0020] Step 207, closing the positive charging switch and the negative charging switch;

[0021] Step 208, start the charging process;

[0022] Step 209, determine whether the total pressure difference between the branches is greater than the set value_1 and less than or equal to the set value_2. If so, execute step 210, otherwise execute step 216:

[0023] Step 210: closing the branch switch and the branch heating switch of a branch with the largest total pressure to put it in a discharge state;

[0024] Step 211, determine whether the pressure difference between the branches is less than or equal to the set value_1, if yes, execute step 212; otherwise, execute step 210:

[0025] Step 212, turning off the branch heating switch;

[0026] Step 213, close the branch switch:

[0027] Step 214, closing the positive charging switch and the negative charging switch;

[0028] Step 215, start the charging process;

[0029] Step 216, closing the branch switch of a branch with the smallest total pressure;

[0030] Step 217, closing the positive charging switch and the negative charging switch;

[0031] Step 218, start the charging process;

[0032] Step 219, the charging request current value is set to 1 / 3 of the standard value;

[0033] Step 220, determining in real time whether the total pressure difference between the branches is less than or equal to the set value_1, if so, executing step 221, if not, returning to step 219;

[0034] Step 221, the BMS charging request current is to reduce the minimum output current of the charging pile;

[0035] Step 222, closing the branch switches of the remaining branches;

[0036] Step 223: The BMS charging request current is restored to a standard value.

[0037] Among them, after the charging process is started, the maximum voltage, minimum voltage and SOC value of each branch are determined in real time during the charging process. When the maximum voltage of any branch reaches the cut-off voltage, the SOC of the branch is reset to 100% and the charging request current is reduced to the minimum value or a fixed value of 5A and the branch switch is cut off, the charging request current of the overall power battery system is reduced, and the remaining branches are continuously charged until all branches are fully charged, and then the charging process is terminated to realize the control of charging; the branches include three, and the charging process includes the steps;

[0038] Step 301, BMS and charging pile perform data exchange;

[0039] Step 302, determining whether the number of full charging times is greater than or equal to a preset number, if so, executing step 303, if not, entering the step of detecting whether the battery has a fault;

[0040] Step 303, determine whether the battery cell of the first branch has reached the cut-off voltage, if yes, proceed to step 304, if no, proceed to step 302:

[0041] Step 304, reducing the charging request current to the minimum current of the charging pile;

[0042] Step 305, disconnect the branch switch of the first branch, and the remaining branches continue to charge;

[0043] Step 306, the charging request current is set to 2 / 3 of the standard value;

[0044] Step 307, determining whether the battery cell of the second branch has reached the cut-off voltage, if yes, executing step 308, if no, executing step 306;

[0045] Step 308, reducing the charging request current to the minimum current of the charging pile;

[0046] Step 309, disconnect the branch switch of the second branch, and the charging process of the remaining branches continues:

[0047] Step 310, the charging request current is 1 / 3 of the standard value;

[0048] Step 311, determining whether the battery cell in the third branch has reached the cut-off voltage, if so, executing step 312, if not, executing step 310;

[0049] Step 312, end the charging process.

[0050] During the charging process, when it is determined in step 302 that the number of full charging times does not meet the condition of the preset number of times, the following steps are further performed:

[0051] Step 313, determine whether there is a battery failure, if not, execute step 314, if yes, enter the charging control steps in the state of battery failure:

[0052] Step 314, determine whether the cut-off voltage is reached, if so, execute step 315; if not, execute step 313;

[0053] Step 315, disconnect the positive charging switch and the negative charging switch, and keep the branch switch closed;

[0054] Step 316, read the branch current value, if a branch current value is ≤5A, disconnect its branch switch; if a branch current value is >5A and lasts for a preset time, forcibly disconnect its branch switch, and record the current and number of times its branch switch is disconnected under load.

[0055] In step 313, it is determined that there is a battery failure, and the following steps are continued:

[0056] Step 317, reducing the charging current to the minimum current of the charging pile;

[0057] Step 318, disconnect the branch switch of the battery fault branch, and record the current and number of times the branch switch is disconnected under load;

[0058] Step 319, the remaining branches continue to charge, and the charging request current is reduced;

[0059] Step 320, storing branch fault status information;

[0060] Step 321, determine whether the cut-off voltage is reached, if so, execute step 322, otherwise execute step 320;

[0061] Step 322, disconnect the positive charging switch and the negative charging switch;

[0062] Step 323, read the remaining branch current value, if a branch current value is ≤5A, disconnect its branch switch; if a branch current value is >5A and lasts for a preset time, forcibly disconnect its branch switch, and record the current and number of times the branch switch is cut off under load.

[0063] A third aspect of the present invention provides a vehicle, including an intelligent charging control system for a power battery system.

[0064] The power battery system intelligent charging control system of the present invention, through the above electrical topology design, can balance the capacity between branches in real time, that is, the high-voltage branch supplements the low-voltage branch to reduce the capacity inconsistency between branches; the connection and disconnection of different branches are realized by controlling the on and off of relays between branches, which can solve the problem of overcharging of battery cells caused by balanced current charging between branches after charging is completed. At the same time, the branch charging balancing strategy is implemented to ensure that the branches can be fully charged and reduce the capacity difference between branches.

[0065] The present invention monitors all monomer information, current information, relay status information, charging pile information, and vehicle control system information of a multi-branch battery system in real time during the charging process; controls branch relays based on a charging control strategy to ensure that each branch battery system can be fully charged; prevents the occurrence of circulation phenomena between multiple branches, and improves the stability of the multi-branch battery system. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 It is a schematic diagram of the intelligent charging control system of the power battery system of the present invention.

[0067] Figure 2 It is a control flow chart of the power battery system intelligent charging control method of the present invention, in which the charging is started after the gun is powered on.

[0068] Figure 3 It is a control flow chart of the charging process after the charging process of the power battery system intelligent charging control method of the present invention starts. DETAILED DESCRIPTION

[0069] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0070] See also Figure 1 As shown, the power battery system intelligent charging control system of the present invention is used to control the charging of a battery system with at least two branches, and the branches are arranged in parallel; each branch includes a battery module composed of N battery boxes connected in series, a charging branch and a heating branch, the positive electrode of each charging branch is connected to a branch switch, the positive electrode of each heating branch is connected to a branch heating switch, and all heating branches can be controlled by any branch heating switch; after the branch switch and the branch heating switch are connected in parallel, they are connected to the charging and discharging positive electrode port of the charging system through the charging and discharging positive electrode switch; the negative electrode of each heating branch is connected to the charging and discharging negative electrode port of the charging system through the charging and discharging negative electrode switch, and the negative electrode of each charging branch is connected to the charging and discharging negative electrode switch through a current sensor.

[0071] Among them, the charging and discharging positive pole switch includes two parallel charging positive pole switches, one discharging positive pole switch, and one pre-charging switch; the discharging positive pole switch is connected to the positive discharge port of the charging system after being connected in parallel with the pre-charging switch; the two parallel charging positive pole switches are each connected to a positive charging port of the charging system.

[0072] Among them, one end of each current sensor is connected to the negative electrode of the battery module formed by the corresponding series battery box, the other end of the current sensor is connected to a terminal of the maintenance switch MSD, and the other terminal of the maintenance switch MSD is connected to the negative electrode charge and discharge switch.

[0073] The charging and discharging negative pole switch includes a discharging negative pole switch and two parallel charging negative pole switches, the two charging negative pole switches are respectively connected to a charging negative pole port of the charging system, and the discharging negative pole switch is connected to the discharging negative pole port.

[0074] In some embodiments, the current sensor is a Hall sensor, or other current sensors are used.

[0075] In some embodiments, the branch switch, branch heating switch, charge and discharge positive switch, and charge and discharge negative switch are implemented by relays, or by other available switches, not limited to relays.

[0076] In some embodiments, the current sensor, branch switch, branch heating switch, charge and discharge positive switch, and charge and discharge negative switch are arranged in a high-voltage box of the vehicle; a battery management system BMS is arranged in the high-voltage box, and the battery management system BMS is connected to the battery monitoring unit CSC inside the battery box through a CAN bus. The battery management system BMS is connected to the vehicle through a CAN bus, and is connected to the charging pile for data exchange during charging.

[0077] It should be noted that in the present application, the battery system is a multi-branch power battery system, and the branches can be multiple, which can be expanded as needed, and the number of branches can be reduced by at least two.

[0078] Each branch includes N battery boxes, the number of which can be expanded, the number of boxes can be reduced or increased, and the N battery boxes are connected in series. Each battery box of each branch contains a heating plate, and the heating plates between the battery boxes are connected in series; the battery boxes of multiple branches are arranged in the same manner as the branch, so that three branches can be output in parallel to increase the discharge power.

[0079] Take three branches as an example, and take the switches using relays and Hall sensors as an example, such as the positive pole of branch one is connected to the branch relay K4 in the high-voltage box, the positive pole of branch two is connected to the branch relay K5 in the high-voltage box, and the positive pole of branch three is connected to the branch relay K6 in the high-voltage box; the negative pole of branch one, the negative pole of branch two, and the negative pole of branch three are connected to the X' of the maintenance switch MSD of the high-voltage box, and each negative pole branch has a Hall sensor; the heating positive pole of branch one is connected to the branch heating relay K41, the heating positive pole of branch two is connected to the branch heating relay K51, and the heating positive pole of branch three is connected to the branch heating relay K61. The three heating positive poles are connected together inside the high-voltage box to achieve synchronous heating. The heating negative pole of branch one, the heating negative pole of branch two, and the heating negative pole of branch one are connected to one end of the discharge negative relay K2.

[0080] Among them, the branch relay K4 corresponding to the branch one inside the high-voltage box is connected to the branch heating relay K41, the branch relay K5 of the branch two inside the high-voltage box is connected to the branch heating relay K51, and the branch relay K6 of the branch three inside the high-voltage box is connected to the branch heating relay K61; at the same time, the branch relay K4, branch relay K5, and branch relay K6 inside the high-voltage box are connected in parallel to realize independent control of the three branches.

[0081] The high-voltage box is connected to the charging pile through the positive charging switch (relay K7, relay K8) and the negative charging switch (relay K9, charging relay K10). The high-voltage box is connected to the vehicle system through the positive discharge switch (relay K1) and the negative discharge switch (relay K2), and relay K1 is connected in parallel with the pre-charge switch (relay K3) to realize high-voltage pre-charge control on the vehicle. The BMS (battery management system) contained in the high-voltage box and the CSC (battery monitoring unit) inside the battery box are connected to exchange data information through the CAN bus. At the same time, the BMS is connected to the vehicle and the charging pile through the CAN bus to exchange data information.

[0082] The present invention determines the system voltage of each branch in a multi-branch battery system, judges the voltage difference between the branches, determines the charging and power-on process, and ensures that each branch can be fully charged normally.

[0083] According to a second aspect of an embodiment of the present invention, a method for intelligent charging control of a power battery system is provided. The method for intelligent charging control of a power battery system is implemented based on the intelligent charging control system of the power battery system. According to the technology of the present invention, the maximum voltage, minimum voltage and SOC value of each branch are determined in real time during the charging process; when it is monitored that the maximum voltage of any branch reaches the cut-off voltage, the SOC of the branch is reset to 100% and the charging request current is reduced to the minimum value or a fixed value of 5A, and the branch switch is cut off; the charging request current of the entire power battery system is reduced, and the remaining branches are continued to be charged until the batteries of all branches are fully charged.

[0084] In some embodiments, the power battery system intelligent charging control method enters the charging process through the following steps, such as Figure 2 As shown, the steps include:

[0085] Step 201, plug in the charging gun to power on and wake up the battery management system BMS;

[0086] Step 202, the BMS obtains the total voltage of each branch and reads the SOC value of each branch;

[0087] Step 203, determine whether there is a battery failure, if yes, go to step 204, otherwise go to step 205;

[0088] Step 204, disconnect charging;

[0089] Step 205, determine whether the total pressure difference between the branches is less than or equal to the set value_1, if yes, execute step 206, if not, execute step 209;

[0090] Step 206, closing the branch switches of all branches;

[0091] Step 207, close the positive charging switch and the negative charging switch; taking the switch as a relay, when closing relays K7 / K9, K8 / K10, if dual-gun charging, K7, K8, K9, K10 are all closed, if single-gun charging, only K7, K9 or K8, K10 are closed.

[0092] Step 208, start the charging process;

[0093] Step 209, determine whether the total pressure difference between the branches is greater than the set value_1 and less than or equal to the set value_2. If so, execute step 210, otherwise execute step 216:

[0094] Step 210: close the branch switch and branch heating switch of a branch with the largest total pressure to put it in a discharge state; taking the switch as an example, if the voltage of branch 1 is the highest, close its corresponding branch charging relay K4 and branch heating relay K41 to put branch 1 in a discharge state and reduce the voltage of branch 1;

[0095] Step 211, determine whether the pressure difference between the branches is less than or equal to the set value_1, if yes, execute step 212; otherwise, execute step 210:

[0096] Step 212, disconnecting the branch heating switch; taking the switch adopting a relay as an example, if the branch heating relay K41 of branch one in step 210 is closed, then the branch heating relay K41 is disconnected at this time, that is, the branch heating relay is disconnected;

[0097] Step 213, closing the branch switch; taking the switch adopting a relay as an example, if the branch relay K4 is closed in step 210, then the branch relay K5 and the branch relay K6 need to be closed at this time, that is, the branch relays are closed;

[0098] Step 214, close the positive charging switch and the negative charging switch; taking the switch adopting a relay as an example, when closing the charging relays K7 / K9, K8 / K10, if it is double-gun charging, then K7, K8, K9, K10 are all closed, if it is single-gun charging, then only K7, K9 or K8, K10 are closed;

[0099] Step 215, start the charging process;

[0100] Step 216, closing the branch switch of a branch with the smallest total pressure; taking the switch as a relay, if the total pressure of branch 1 is the smallest, then closing relay K4;

[0101] Step 217, close the positive charging switch and the negative charging switch; taking the switch as a relay, when closing the charging relays K7 / K9, K8 / K10, if it is double-gun charging, then K7, K8, K9, K10 are all closed, if it is single-gun charging, then only K7, K9 or K8, K10 are closed;

[0102] Step 218, start the charging process;

[0103] Step 219, the charging request current value is set to 1 / 3 of the standard value;

[0104] Step 220, determining in real time whether the total pressure difference between the branches is less than or equal to the set value_1, if so, executing step 221, if not, returning to step 219;

[0105] Step 221, the BMS charging request current is to reduce the minimum output current of the charging pile or a fixed value, such as 5A;

[0106] Step 222, close the branch switches of the remaining branches; taking the switch using relays as an example, for example, in the previous step, the branch relay K4 of branch one is closed, then in this step 222, the branch relay K5 of branch two and the branch relay K6 of branch three are closed.

[0107] Step 223: The BMS charging request current is restored to a standard value.

[0108] In the above technical solution, step 203 determines whether there is a battery fault, and the battery fault includes at least one of a battery high temperature fault, a battery extreme undervoltage fault or a loop interlock fault, etc., which affects the normal charging of the battery.

[0109] In the above technical solution, in step 223, the standard value is the normal requested current of the power battery system after all branches of the battery are turned on for charging.

[0110] In the above technical solution, it should be noted that the set value_1 and the set value_2 can be set according to the number of battery cell strings in the system.

[0111] In the embodiment of the present application, after the charging process is started, the maximum voltage, minimum voltage and SOC value of each branch are determined in real time during the charging process. When the maximum voltage of any branch reaches the cut-off voltage, the SOC of the branch is reset to 100% and the charging request current is reduced to the minimum value or a fixed value of 5A and the branch switch is cut off, thereby reducing the charging request current of the overall power battery system, and continuing to charge the remaining branches until all branches are fully charged, and then the charging process is terminated, thereby realizing charging control.

[0112] Specifically, the intelligent control of charging is realized by executing the following steps, taking three branches as an example, see Figure 3 As shown, the following execution steps are included:

[0113] Step 301, BMS and charging pile perform data exchange;

[0114] Step 302, determining whether the number of full charging times is greater than a preset number, if so, executing step 303, if not, executing step 313;

[0115] Step 303, determine whether the battery cell of the first branch has reached the cut-off voltage, if yes, proceed to step 304, if no, proceed to step 302:

[0116] Step 304, reducing the charging request current to the minimum current of the charging pile;

[0117] Step 305, disconnect the branch switch of the first branch, and the remaining branches continue to charge;

[0118] Step 306, the charging request current is set to 2 / 3 of the standard value;

[0119] Step 307, determining whether the battery cell of the second branch has reached the cut-off voltage, if yes, executing step 308, if no, executing step 306;

[0120] Step 308, reducing the charging request current to the minimum current of the charging pile;

[0121] Step 309, disconnect the branch switch of the second branch, and the charging process of the remaining branches continues:

[0122] Step 310, the charging request current is 1 / 3 of the standard value;

[0123] Step 311, determining whether the battery cell in the third branch has reached the cut-off voltage, if so, executing step 312, if not, executing step 310;

[0124] Step 312, ending the charging process;

[0125] In the above scheme, in the step 302, the number of full charges is determined, and the number of full charges refers to the number of times the battery is normally fully charged. For example, if N is 10, that is, every 10 charges, when the battery reaches full charge, one branch is disconnected at a time to allow all branches to be fully charged, thereby reducing the capacity difference between branches. In this way, step 303 is executed every 10 full charges, and the charging time is extended by disconnecting one branch at a time. If the number is less than 10 times, step 313 is executed, and the charging time is reduced after one branch reaches full charge.

[0126] In the present application, through the above steps 301 to 312, intelligent charging control is implemented in the case of no battery failure, and the control of balanced full charging of branches is implemented, wherein the number of full charging times can be set to 10 times or 30 times as needed. In the present application, when it is judged that the number of full charging times is greater than N times, a separate full charging process for each branch is executed, and the branch relay strategy is disconnected in turn, thereby realizing intelligent control of the full charging of each branch. After all branches are fully charged, the normal charging process is terminated.

[0127] In some embodiments, during the charging process, after determining that the number of full charging times does not meet or exceed a predetermined number, such as N times, it is further determined whether there is a battery failure, and the following steps are performed according to different situations:

[0128] Step 313, determine whether there is a battery failure, if not, execute step 314, if yes, execute step 317:

[0129] Step 314, determine whether the cut-off voltage is reached, if so, execute step 315; if not, execute step 313;

[0130] Step 315, disconnect the positive charging switch and the negative charging switch, and keep the branch switches of each branch closed;

[0131] Step 316, read the branch current value, if a branch current value is ≤5A, disconnect its branch switch; if a branch current value is >5A and lasts for a preset time, forcibly disconnect its branch switch, and record the current and number of times its branch switch is disconnected under load.

[0132] Through the above steps, intelligent charging control is achieved when it is detected that there is no battery fault.

[0133] In step 313, it is determined whether there is a battery fault, wherein the battery fault includes at least one of a battery high temperature fault, a battery limit undervoltage fault, a loop interlock fault, and the like, which affects the normal charging of the battery.

[0134] In the above step 314, the determination of whether the cut-off voltage is reached is to determine whether one cell in the battery of any branch has reached the cut-off voltage, and if so, charging is stopped.

[0135] In the above embodiment, in step 316, the current value of each branch Hall sensor is read, and the capacity between the branches is balanced by controlling the disconnection of the branch relay. If the current of any branch is ≤5A, the corresponding branch relay is disconnected; if the current value of any branch Hall sensor is continuously greater than 5A for 30 minutes, the branch relay is forcibly disconnected, and the current and number of times the branch relay is disconnected under load are recorded.

[0136] When it is determined that there is a battery failure, the following steps are performed to control charging:

[0137] Step 317, reducing the charging current to the minimum current of the charging pile;

[0138] Step 318, forcibly disconnecting the branch switch of the branch with the battery fault, and recording the current and number of times the branch switch is disconnected under load;

[0139] Step 319, the remaining branches continue to charge, and the charging request current is reduced;

[0140] Step 320, storing branch fault status information;

[0141] Step 321, determine whether the cut-off voltage is reached, if so, execute step 322, otherwise execute step 320;

[0142] Step 322, disconnect the positive charging switch and the negative charging switch;

[0143] Step 323, read the current values ​​of the remaining branches. If the current of a branch is ≤5A, disconnect its branch switch; if the current value of a branch is >5A and lasts for a preset time, forcibly disconnect its branch switch and record the current and number of times its branch switch is disconnected under load.

[0144] In the above steps, through steps 317 to 323, intelligent operation control is implemented to end the charging process when a battery failure is detected, and the current and number of load cutoffs of the branch switch and the fault condition information are recorded to facilitate subsequent maintenance, detection, and replacement processing.

[0145] In the above step 321, judging whether the cut-off voltage is reached refers to judging whether the battery cells of the branch circuit without battery failure have reached the cut-off voltage.

[0146] A third aspect of an embodiment of the present invention provides a vehicle, including a power battery system intelligent charging control system, wherein the power battery system intelligent charging control system adopts the above-mentioned power battery system intelligent charging control method to perform intelligent charging control on the power batteries on the vehicle, especially a multi-branch power battery system.

[0147] The basic principles and main features of the present invention and the advantages of the present invention are shown and described above. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention.

[0148] Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is therefore intended that all changes falling within the meaning and range of equivalent elements of the claims are included in the present invention.

[0149] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. Intelligent charging control system for power battery system, characterized in that: Used to control the charging of a battery system with at least two branches, which are arranged in parallel; each branch includes a battery module composed of N battery boxes connected in series, a charging branch and a heating branch, the positive pole of each charging branch is connected to a branch switch, the positive pole of each heating branch is connected to a branch heating switch, and all heating branches can be controlled by any branch heating switch; after the branch switches and branch heating switches are connected in parallel, they are connected to the charging and discharging positive pole port of the charging system through the charging and discharging positive pole switch; the negative pole of each heating branch is connected to the charging and discharging negative pole port of the charging system through the charging and discharging negative pole switch, and the negative pole of each charging branch is connected to the charging and discharging negative pole switch through a current sensor.

2. According to claim 1, the power battery system intelligent charging control system is characterized in that: The charging and discharging positive pole switch includes two parallel charging positive pole switches, one discharging positive pole switch, and one pre-charging switch; the discharging positive pole switch is connected to the pre-charging switch in parallel and then connected to the positive discharge port of the charging system; the two parallel charging positive pole switches are each connected to a positive charging port of the charging system.

3. The power battery system intelligent charging control system according to claim 1, characterized in that: One end of each current sensor is connected to the negative electrode of the battery module formed by the corresponding series battery box, and the other end of the current sensor is connected to one terminal of the maintenance switch MSD, and the other terminal of the maintenance switch MSD is connected to the negative electrode charge and discharge switch.

4. The power battery system intelligent charging control system according to claim 1, characterized in that: The charge and discharge negative pole switch comprises a discharge negative pole switch and two parallel charge negative pole switches, the two charge negative pole switches are respectively connected to a charge negative pole port of the charging system, and the discharge negative pole switch is connected to the discharge negative pole port.

5. The power battery system intelligent charging control system according to claim 1, characterized in that: The current sensor adopts a Hall sensor; preferably, the branch switch, branch heating switch, charge and discharge positive switch and charge and discharge negative switch adopt relays; preferably, the current sensor, branch switch, branch heating switch, charge and discharge positive switch and charge and discharge negative switch are arranged in the high-voltage box of the vehicle; a battery management system BMS is arranged in the high-voltage box, and the battery management system BMS is connected to the battery monitoring unit CSC inside the battery box through the CAN bus, and the battery management system BMS is connected to the vehicle through the CAN bus, and is connected to the charging column for data exchange during charging.

6. A power battery system intelligent charging control method, characterized in that: The intelligent charging control system of the power battery system according to any one of claims 1 to 5 is implemented; comprising the steps of: Step 201, plug in the charging gun to power on and wake up the battery management system BMS; Step 202, the BMS obtains the total voltage of each branch and reads the SOC value of each branch; Step 203, determine whether there is a battery failure, if yes, go to step 204, otherwise go to step 205; Step 204, disconnect charging; Step 205, determine whether the total pressure difference between the branches is less than or equal to the set value_1, if yes, execute step 206, if not, execute step 209; Step 206, closing the branch switches of all branches; Step 207, close the positive charging switch and the negative charging switch; Step 208, start the charging process; Step 209, determine whether the total pressure difference between the branches is greater than the set value_1 and less than or equal to the set value_2. If so, execute step 210, otherwise execute step 216: Step 210: closing the branch switch and the branch heating switch of a branch with the largest total pressure to put it in a discharge state; Step 211, determine whether the pressure difference between the branches is less than or equal to the set value_1, if yes, execute step 212; Otherwise, execute step 210: Step 212, turning off the branch heating switch; Step 213, close the branch switch: Step 214, closing the positive charging switch and the negative charging switch; Step 215, start the charging process; Step 216, closing the branch switch of a branch with the smallest total pressure; Step 217, closing the positive charging switch and the negative charging switch; Step 218, start the charging process; Step 219, the charging request current value is set to 1 / 3 of the standard value; Step 220, determining in real time whether the total pressure difference between the branches is less than or equal to the set value_1, if so, executing step 221, if not, returning to step 219; Step 221, the BMS charging request current is to reduce the minimum output current of the charging pile; Step 222, closing the branch switches of the remaining branches; Step 223: The BMS charging request current is restored to a standard value.

7. The power battery system intelligent charging control method according to claim 6, characterized in that: After the charging process is started, the maximum voltage, minimum voltage and SOC value of each branch are determined in real time during the charging process. When the maximum voltage of any branch reaches the cut-off voltage, the SOC of the branch is reset to 100% and the charging request current is reduced to the minimum value or a fixed value of 5A and the branch switch is cut off to reduce the charging request current of the overall power battery system. The remaining branches continue to be charged until all branches are fully charged, and then the charging process is terminated to achieve charging control; the branches include three, and the charging process includes the following steps: Step 301, the BMS and the charging pile perform data exchange; Step 302, determining whether the number of full charging times is greater than or equal to a preset number, if so, executing step 303, if not, entering the step of detecting whether the battery has a fault; Step 303, determine whether the battery cell of the first branch has reached the cut-off voltage, if yes, proceed to step 304, if no, proceed to step 302: Step 304, reducing the charging request current to the minimum current of the charging pile; Step 305, disconnect the branch switch of the first branch, and the remaining branches continue to charge; Step 306, the charging request current is set to 2 / 3 of the standard value; Step 307, determining whether the single battery of the second branch has reached the cut-off voltage, if yes, executing step 308, if no, executing step 306; Step 308, reducing the charging request current to the minimum current of the charging pile; Step 309, disconnect the branch switch of the second branch, and the charging process of the remaining branches continues: Step 310, the charging request current is 1 / 3 of the standard value; Step 311, determining whether the single cell in the third branch has reached the cut-off voltage, if so, executing step 312, if not, executing step 310; Step 312, end the charging process.

8. The power battery system intelligent charging control method according to claim 7, characterized in that: During the charging process, when it is determined in step 302 that the number of full charging times does not meet the condition of the preset number of times, the following steps are further performed: Step 313, determine whether there is a battery failure, if not, execute step 314, if yes, enter the charging control steps in the state of battery failure: Step 314, determine whether the battery cell reaches the cut-off voltage, if yes, execute step 315; if no, execute step 313; Step 315, disconnect the positive charging switch and the negative charging switch, and keep the branch switch closed; Step 316, read the remaining branch current value, if a branch current value is ≤5A, disconnect its branch switch; if a branch current value is >5A and lasts for a preset time, forcibly disconnect its branch switch, and record the current and number of times the branch switch is disconnected under load.

9. The power battery system intelligent charging control method according to claim 8, characterized in that: In step 313, it is determined that there is a battery failure, and the following steps are continued: Step 317, reducing the charging current to the minimum current of the charging pile; Step 318, disconnect the branch switch of the battery fault branch, and record the current and number of times the branch switch is disconnected under load; Step 319, the remaining branches continue to charge, and the charging request current is reduced; Step 320, storing branch fault status information; Step 321, determine whether the battery cell reaches the cut-off voltage, if so, execute step 322, otherwise execute step 320; Step 322, disconnect the positive charging switch and the negative charging switch; Step 323, read the current values ​​of the remaining branches. If the current of a branch is ≤5A, disconnect its branch switch; if the current value of a branch is >5A and lasts for a preset time, forcibly disconnect its branch switch and record the current and number of times its branch switch is disconnected under load.

10. A vehicle, characterized in that It includes the power battery system intelligent charging control system as described in any one of claims 1-5.

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