A mobile charging vehicle capable of detecting battery health and implementation method thereof

Abstract

The present invention discloses a mobile charging vehicle capable of detecting battery health and its implementation method. The present invention can not only charge the charging vehicle with various charging piles, but also meet the power replenishment needs of various electric vehicles through AC slow charging and DC fast charging, and can also realize the rapid detection of the battery health of the charged vehicle; only one bidirectional DCDC power conversion module is used to complete the boost and buck operations of the mobile charging vehicle, thereby completing the charging of the high-voltage battery pack and the discharge of the charged vehicle; only through the battery information of the charged vehicle and the charging process information, the online detection of the on-board battery health of the new energy vehicle can be realized, without the need for long-term battery life cycle tests and full charge and discharge tests; combined with the multi-time scale extended Kalman filter algorithm and the recursive least squares method, the battery parameter identification and battery health detection accuracy are effectively improved; at the same time, the detection stop condition is set to ensure the reliability and stability of the battery health results.

Description

Technical Field

[0001] The present invention relates to electric vehicle battery detection technology, and in particular to a mobile charging vehicle capable of detecting battery health and an implementation method thereof. Background Art

[0002] In order to protect the environment and save energy, lithium-ion batteries are being widely used in the field of electric vehicles. However, the limited range of electric vehicles and the incomplete layout of charging piles are key factors restricting their further development. In the absence of charging piles nearby, mobile charging vehicles can be used as emergency charging devices to timely recharge various electric vehicles.

[0003] Accurately evaluating the health of electric vehicle batteries is conducive to timely understanding of battery health status, as well as the development of electric vehicle insurance business and battery recycling. However, most of the existing battery health testing equipment is dedicated equipment, which is inconvenient to move and has a single function. Before testing, a large number of battery aging tests and vehicle full charge and discharge tests are required, which is time-consuming and labor-intensive. At the same time, online health estimation also faces the problem of data saturation and difficulty in ensuring accuracy. Summary of the invention

[0004] In order to solve the above problems existing in the prior art, the present invention proposes a mobile charging vehicle capable of detecting battery health and an implementation method thereof, so as to realize the function of quickly recharging electric vehicles without the need for a DC fast charging pile, and at the same time detect the battery health of the charged vehicle.

[0005] An object of the present invention is to provide a mobile charging vehicle capable of detecting battery health.

[0006] The mobile charging vehicle capable of detecting battery health of the present invention comprises: a high-voltage battery pack, a first power distribution box, a second power distribution box, a bidirectional direct current to direct current (DCDC) power conversion module, a direct current to alternating current (DCAC) power conversion module, an AC charger, an AC output socket, an AC charging socket, a first DC charging socket, a second DC charging socket, an air switch, a low-voltage power supply module, a charging start button, an emergency stop button, a DC charging gun, a thermal management system, a vehicle control module, a touch-sensitive LCD screen and a data recording module; wherein the high-voltage battery pack is respectively connected to the bidirectional DCDC power conversion module, the AC charger, the first DC charging socket, the DCAC power conversion module and the low-voltage power supply module via the first power distribution box; the bidirectional DCDC power conversion module is respectively connected to the DC charging gun, the second DC charging socket and the thermal management system via the second power distribution box; the AC charger is connected to the AC output socket; the DCAC power conversion module is connected to the AC output socket; the low-voltage power supply module is respectively connected to the vehicle control module, the touch-sensitive LCD screen, the data recording module and the thermal management system;

[0007] The vehicle control module includes a first DC charging socket control board, a second DC charging socket control board, a DC charging gun control board and a vehicle controller. The built-in communication modules of the first DC charging socket control board, the second DC charging socket control board and the DC charging gun control board are respectively connected to the communication lines of the first DC charging socket, the second DC charging socket and the DC charging gun. The first DC charging socket control board, the first DC charging socket control board, the DC charging gun control board, the vehicle controller, the high-voltage battery pack, the DCAC power conversion module, the bidirectional DCDC power conversion module, the AC charger, the data recording module, the touch-sensitive LCD screen and the compressor and PTC heater in the thermal management system are all provided with their own communication modules and have communication functions. All these communication modules are interconnected to form a vehicle communication network of the mobile charging vehicle.

[0008] The first distribution box includes a first distribution box shell, a high-voltage battery pack interface, a bidirectional DCDC power conversion module interface, an AC charger interface, a first DC charging socket interface, a DCAC power conversion module interface, a low-voltage power supply module interface, a battery high-voltage relay, a first high-voltage relay, and a second high-voltage relay; the interior of the first distribution box shell is hollow, and the high-voltage battery pack interface, the bidirectional DCDC power conversion module input interface, the AC charger interface, the first DC charging socket interface, the DCAC power conversion module interface and the low-voltage power supply module interface are respectively arranged on the surface of the first distribution box shell, and the battery high-voltage relay, the first high-voltage relay and the second high-voltage relay are arranged in the first distribution box shell; the output end of the high-voltage battery pack is connected to the high-voltage battery pack interface, and the high-voltage battery pack interface is connected to the bidirectional DCDC power conversion module input interface through the battery high-voltage relay. The high-voltage battery pack interface is connected to the AC charger interface through the battery high-voltage relay and the first high-voltage relay, the high-voltage battery pack interface is connected to the first DC charging socket interface through the battery high-voltage relay and the second high-voltage relay, and the high-voltage battery pack interface is also connected to the DCAC power conversion module interface and the low-voltage power supply module interface respectively; the bidirectional DCDC power conversion module input interface is connected to the input end of the bidirectional DCDC power conversion module; the AC charger interface is connected to the AC charger; the first DC charging socket interface is connected to the first DC charging socket; the DCAC power conversion module interface is connected to the DCAC power conversion module; the low-voltage power supply module interface is connected to the low-voltage power supply module through the air switch; the vehicle controller is connected to the battery high-voltage relay, the first high-voltage relay and the second high-voltage relay through the control line, respectively, for controlling the opening and closing of each high-voltage relay;

[0009] The second power distribution box includes a second power distribution box housing, a bidirectional DCDC power conversion module output interface, a second DC charging socket interface, a thermal management system interface, a DC charging gun interface, a third high-voltage relay and a fourth high-voltage relay; the interior of the second power distribution box housing is hollow, and the bidirectional DCDC power conversion module output interface, the second DC charging socket interface, the thermal management system interface and the DC charging gun interface are respectively arranged on the surface of the second power distribution box housing, and the third high-voltage relay and the fourth high-voltage relay are arranged in the second power distribution box housing; the output end of the bidirectional DCDC power conversion module is connected to the bidirectional DCDC power conversion module output interface; the DCDC power conversion module output interface is connected to the second DC charging socket interface; the DCDC power conversion module output interface is connected to the DC charging gun interface through the third high-voltage relay; the DCDC power conversion module output interface is connected to the thermal management system interface through the fourth high-voltage relay; the second DC charging socket interface is connected to the second DC charging socket; the DC charging gun interface is connected to the DC charging gun through the charging start button and the emergency stop button; the thermal management system interface is connected to the compressor and thermistor type (Positive Temperature Coefficient, PTC) heater; the vehicle controller is connected to the third high-voltage relay and the fourth high-voltage relay through control lines, respectively, for opening and closing each high-voltage control relay;

[0010] The charging and discharging modes of the mobile charging vehicle include: first DC charging mode, second DC charging mode, AC slow charging mode, fast charging mode, health detection mode and AC output mode:

[0011] In the first DC charging mode, the first DC charging socket is connected to the DC charging pile, the vehicle controller controls the battery high-voltage relay and the second high-voltage relay to close, and the other high-voltage relays are disconnected to charge the high-voltage battery pack; during the charging process, the first DC charging socket control board obtains the real-time voltage, state of charge (State of Charge, SOC) and maximum charging current information of the high-voltage battery pack from the vehicle communication network in real time, and completes the controller area network (Controller Area Network, CAN) communication between the mobile charging vehicle and the charging pile;

[0012] In the second DC charging mode, the second DC charging socket is connected to a DC charging pile whose maximum voltage exceeds the maximum voltage of the high-voltage battery pack. The vehicle controller controls the battery high-voltage relay and the fourth high-voltage relay to close, and the other high-voltage relays to disconnect, so as to charge the high-voltage battery pack. During the charging process, the second DC charging socket control board obtains the real-time voltage, SOC and maximum charging current information of the high-voltage battery pack from the vehicle communication network in real time. The maximum charging current of the second DC charging mode is the smaller value of the maximum charging current of the high-voltage battery pack and the maximum allowable current of the bidirectional DCDC power conversion module. At the same time, the voltage at the output end of the bidirectional DCDC power conversion module is controlled to be lower than the maximum voltage of the DC charging pile and to maintain a constant voltage, and then the voltage is boosted through the bidirectional DCDC power conversion module.

[0013] In the AC slow charging mode, the AC charging socket is connected to the AC charging pile, the vehicle controller controls the battery high-voltage relay and the first high-voltage relay to close, and the other high-voltage relays to disconnect, so as to charge the high-voltage battery pack; during the charging process, the vehicle controller is responsible for completing the confirmation of the slow charging process and outputting the slow charging current allowed at this time; the AC charger obtains the slow charging current allowed at this time from the vehicle communication network and adjusts the voltage at the output end of the AC charger;

[0014] In the fast charging mode, the DC charging gun is connected to the battery of the charged vehicle, and the fast charging mode is selected on the touch-screen LCD screen. The vehicle controller controls the battery high-voltage relay and the third high-voltage relay to close, and the other high-voltage relays are disconnected, so that the high-voltage battery pack quickly charges the charged vehicle. During the charging process, the DC charging gun control board completes the CAN communication between the mobile charging vehicle and the charged vehicle, and obtains the maximum discharge current of the high-voltage battery pack from the vehicle communication network, thereby adjusting the output voltage of the bidirectional DCDC power conversion module to control the output current. At this time, the actual output current is the smaller value of the maximum discharge current of the high-voltage battery pack and the required current of the charged vehicle, thereby realizing fast DC charging for the charged vehicle.

[0015] In the health detection mode, the DC charging gun is connected to the battery of the charged vehicle, and the health detection mode is selected on the touch-screen LCD screen. The vehicle controller controls the battery high-voltage relay and the third high-voltage relay to close, and the other high-voltage relays are disconnected. The battery health of the charged vehicle is detected by a mobile charging vehicle. During the charging process, the vehicle controller adjusts the maximum discharge current of the high-voltage battery pack in real time, and the current range is 0 to the smaller value of the required current of the charged vehicle and the maximum discharge current of the high-voltage battery pack, thereby limiting the maximum output current of the DCDC power conversion module outlet, so that the charged vehicle is charged in a specific pulse current form, and its health is detected according to the voltage response of the charged vehicle.

[0016] In the first DC charging mode, the second DC charging mode, the AC slow charging mode, the fast charging mode and the health detection mode, the battery high voltage relay protects the high voltage battery pack from overcurrent damage during the charging and discharging process;

[0017] In AC output mode, the AC output socket is connected to the electrical appliance that needs power;

[0018] The vehicle controller controls the opening and closing of the first high-voltage relay, the second high-voltage relay, the third high-voltage relay and the fourth high-voltage relay, and at most only one of the four high-voltage relays is closed at the same time to ensure the singleness of the charging and discharging mode of the mobile charging vehicle.

[0019] The thermal management system includes: a compressor, an outdoor heat exchanger, a thermal expansion valve, a plate heat exchanger, a PTC heater, a first temperature sensor, a second temperature sensor, a water pump and a three-way valve; wherein, the mobile charging vehicle adopts an integrated thermal management circuit including a coolant circuit and a refrigerant circuit: in the coolant circuit, one side of the high-voltage battery pack is connected to the PTC heater through a water pipe, a first temperature sensor is arranged on the water pipe connecting the high-voltage battery pack to the PTC heater, and the PTC heater is connected to the first outlet of the three-way valve; one side of the bidirectional DCDC power conversion module is connected to the second outlet of the three-way valve through a pipeline. The second outlet, a second temperature sensor is set on the pipeline connecting the two-way DCDC power conversion module to the second outlet of the three-way valve, the other side of the high-voltage battery pack and the other side of the two-way DCDC power conversion module are connected to one side of the water pump, the other side of the water pump is connected to the first interface of the plate heat exchanger, and the second interface of the plate heat exchanger is connected to the inlet of the three-way valve; in the refrigerant circuit, the outlet of the compressor, the outdoor heat exchanger and the inlet of the thermal expansion valve are connected in this way, the outlet of the thermal expansion valve is connected to the third interface of the plate heat exchanger, and the fourth interface of the plate heat exchanger is connected to the inlet of the compressor. The first temperature sensor, the second temperature sensor, the three-way valve and the water pump are connected to the vehicle controller of the vehicle control module through control lines respectively; the thermal management system is used to keep the high-voltage battery pack and the two-way DCDC power conversion module in a suitable operating temperature range.

[0020] The data recording module is connected to the host computer through its own communication module; it obtains the charging information of the charged vehicle from the vehicle communication network, including battery type, SOC, battery voltage, battery current, battery temperature and battery cell maximum voltage information; and stores it in the host computer to record the battery health of the charged vehicle and build a new energy vehicle charging database.

[0021] The touch-screen LCD is used to display information about the high-voltage battery pack, bidirectional DCDC power conversion module and vehicle control module; at the same time, the touch-screen LCD can set the thresholds for overvoltage warning, undervoltage warning and overtemperature warning of the bidirectional DCDC power conversion module; when the DC charging gun is connected to the charged vehicle, the touch-screen LCD is also used to display the charging information of the charged vehicle and to select the fast charging mode or the health detection mode.

[0022] The vehicle control module includes: a vehicle controller, a first DC charging socket control board, a second DC charging socket control board, and a DC charging gun control board; the vehicle controller is used to estimate the state of the high-voltage battery pack, determine the charging and discharging mode of the mobile charging vehicle, and perform thermal management control; the vehicle controller first estimates the state of charge (State of Charge, SOC) and power state (State of Power, SOP) of the high-voltage battery pack based on the battery cell information obtained from the vehicle communication network to prevent overcharging and over-discharging of the battery, and uploads the battery pack status to the vehicle communication network; secondly, the vehicle controller determines the charging and discharging mode of the mobile charging vehicle based on the connection status of the AC charging socket, the first DC charging socket, the second DC charging socket, and the DC charging gun at this time, adjusts the maximum charging and discharging current of the high-voltage battery pack, and controls the opening and closing of the battery high-voltage relay; finally, according to the temperature of the high-voltage battery pack and the bidirectional DCDC power conversion module, the thermal management mode of the mobile charging vehicle is determined, and the working state of the thermal management system components is controlled. The thermal management mode of the mobile charging vehicle includes a single cooling mode of the high-voltage battery pack, a single cooling mode of the bidirectional DCDC power conversion module, a dual cooling mode of the high-voltage battery pack and the bidirectional DCDC power conversion module, and a single hot mode of the high-voltage battery pack.

[0023] The first DC charging socket control board is used to cooperate with the first DC charging socket to realize the first DC charging mode in the charging and discharging mode of the mobile charging vehicle; the second DC charging socket control board is used to cooperate with the second DC charging socket to realize the second DC charging mode in the charging and discharging mode of the mobile charging vehicle; the DC charging gun control board is used to cooperate with the DC charging gun to realize the fast charging mode and health detection mode in the charging and discharging mode of the mobile charging vehicle.

[0024] Another object of the present invention is to provide a method for implementing a mobile charging vehicle that can detect battery health.

[0025] The method for implementing a mobile charging vehicle capable of detecting battery health of the present invention comprises the following steps:

[0026] The charging and discharging modes of the mobile charging vehicle include: first DC charging mode, second DC charging mode, AC slow charging mode, fast charging mode, health detection mode and AC output mode:

[0027] a) In the first DC charging mode, the first DC charging socket is connected to the DC charging pile, the vehicle controller controls the battery high-voltage relay and the second high-voltage relay to close, and the other high-voltage relays are disconnected to charge the high-voltage battery pack; during the charging process, the first DC charging socket control board obtains the real-time voltage, SOC and maximum charging current information of the high-voltage battery pack from the vehicle communication network in real time, and completes the controller area network (CAN) communication between the mobile charging vehicle and the charging pile;

[0028] b) In the second DC charging mode, the second DC charging socket is connected to a DC charging pile whose maximum voltage exceeds the maximum voltage of the high-voltage battery pack. The vehicle controller controls the battery high-voltage relay and the fourth high-voltage relay to close to charge the high-voltage battery pack, and the other high-voltage relays are disconnected; during the charging process, the second DC charging socket control board obtains the real-time voltage, SOC and maximum charging current information of the high-voltage battery pack from the vehicle communication network in real time. The maximum charging current of the second DC charging mode is the smaller value of the maximum charging current of the high-voltage battery pack and the maximum allowable current of the bidirectional DCDC power conversion module. At the same time, the voltage at the output end of the bidirectional DCDC power conversion module is controlled to be lower than the maximum voltage of the DC charging pile and maintained at a constant voltage, and then the voltage is boosted through the bidirectional DCDC power conversion module;

[0029] c) In the AC slow charging mode, the AC charging socket is connected to the AC charging pile, the vehicle controller controls the battery high-voltage relay and the first high-voltage relay to close, and the other high-voltage relays to disconnect, so as to charge the high-voltage battery pack; during the charging process, the vehicle controller is responsible for completing the confirmation of the slow charging process and outputting the slow charging current allowed at this time according to the national standard protocol; the AC charger obtains the slow charging current allowed at this time from the vehicle communication network and adjusts the voltage at the output end of the AC charger;

[0030] d) In the fast charging mode, the DC charging gun is connected to the battery of the charged vehicle, and the fast charging mode is selected on the touch-screen LCD screen. The vehicle controller controls the battery high-voltage relay and the third high-voltage relay to close, and the other high-voltage relays are disconnected, so that the high-voltage battery pack quickly charges the charged vehicle; during the charging process, the DC charging gun control board completes the CAN communication between the mobile charging vehicle and the charged vehicle, and obtains the maximum discharge current of the high-voltage battery pack from the vehicle communication network, thereby adjusting the output voltage of the bidirectional DCDC power conversion module to control the output current. At this time, the actual output current is the smaller value of the maximum discharge current of the high-voltage battery pack and the required current of the charged vehicle, thereby realizing fast DC charging for the charged vehicle;

[0031] e) In the health detection mode, the DC charging gun is connected to the battery of the charged vehicle, and the health detection mode is selected on the touch-screen LCD screen. The vehicle controller controls the battery high-voltage relay and the third high-voltage relay to close, and the other high-voltage relays are disconnected. The battery health of the charged vehicle is detected by a mobile charging vehicle; during the charging process, the vehicle controller adjusts the maximum discharge current of the high-voltage battery pack in real time, thereby limiting the maximum output current of the DCDC power conversion module outlet, so that the charged vehicle is charged in a specific pulse current form, and according to the voltage response of the charged vehicle, the recursive least squares method is used to iteratively update the battery parameters, and the Kalman filter algorithm is used to estimate the SOC and polarization voltage at the micro scale, and the battery capacity is estimated at the macro scale, and finally the battery health is obtained;

[0032] f) In AC output mode, the AC output socket is connected to the electrical appliances that need power supply;

[0033] In the first DC charging mode, the second DC charging mode, the AC slow charging mode, the fast charging mode and the health detection mode, the battery high voltage relay protects the high voltage battery pack from overcurrent damage during the charging and discharging process;

[0034] The vehicle controller controls the opening and closing of the first high-voltage relay, the second high-voltage relay, the third high-voltage relay and the fourth high-voltage relay, and at most only one of the four high-voltage relays is closed at the same time to ensure the singleness of the charging and discharging mode of the mobile charging vehicle.

[0035] In step e), the battery health of the charged vehicle is detected in the health detection mode, which specifically includes the following steps: 1) pre-storing SOC-open circuit voltage curves of various types of batteries in the vehicle controller;

[0036] 2) Connect the DC charging gun of the mobile charging vehicle to the fast charging port of the vehicle being charged, select the health detection mode on the touch screen, and press the charging start button;

[0037] 3) Obtain the type and rated capacity parameters of the battery, and call the SOC-open circuit voltage curve of the corresponding type of battery from the vehicle controller;

[0038] 4) The maximum output current of the bidirectional DCDC power conversion module outlet is adjusted through the DC charging gun control board to control the charging current of the charged vehicle. The charging current includes the following stages:

[0039] i. The initial stage is a zero current stage, which lasts between 10 and 40 seconds, so as to obtain the battery voltage of the vehicle being charged when it is powered on as the open circuit voltage;

[0040] ii. Pulse current excitation and zero current stage, used to identify the initial value of the battery parameters of the charged vehicle. The pulse current excitation magnitude is the smaller value of the required current of the charged vehicle and the 1C discharge rate of the high-voltage battery pack. The pulse duration is between 5 and 15 seconds, and the zero current duration is between 40 and 100 seconds.

[0041] iii. The square wave current excitation stage is used to online calculate the SOC, equivalent circuit model battery parameters and battery capacity of the battery of the charged vehicle, so as to realize the online detection of the battery health of the charged vehicle. The square wave period is between 30 and 60 seconds, the duty cycle is 20% to 70%, the square wave peak value is the smaller value of the demand current of the charged vehicle and the maximum discharge current of the high-voltage battery pack, and the square wave valley value adopts non-zero current, ranging from 4 to 10A;

[0042] 5) Obtain the battery charging current and battery voltage of the charged vehicle through the vehicle communication network, and use Kalman filtering to estimate the SOC and polarization voltage at the micro scale;

[0043] 6) Since the ohmic internal resistance of the battery is mainly reflected in the high frequency band, while the polarization internal resistance and polarization capacitance are at a lower frequency band, the recursive least squares method is used to iteratively update the battery parameters;

[0044] 7) According to the SOC and polarization voltage of the battery obtained in step 5), the battery capacity is estimated at a macro scale using Kalman filtering, and the battery health is calculated using the battery capacity;

[0045] 8) Repeat 4) to 7) and use two evaluation indicators to evaluate the reliability of the battery health. When the two evaluation indicators are met, charging is terminated.

[0046] Among them, in step 1), the SOC-open circuit voltage curves of various types of batteries include SOC-open circuit voltage curves of lead-acid batteries, ternary material batteries, lithium iron phosphate batteries, nickel-hydrogen batteries, lithium manganese oxide batteries, cobalt oxide batteries, polymer lithium ion batteries and lithium titanate batteries.

[0047] In step 5), the Kalman filter estimates the battery SOC and polarization voltage at a microscopic scale; specifically, the following steps are included:

[0048] i. The state equation of the battery is expressed as:

[0049]

[0050] Among them, X k is the battery state at the kth moment, A k and B k are the state equation coefficient matrices at the kth moment, U p,k-1 and U p,k are the polarization voltage at the k-1th moment and the kth moment, SOCk-1 and SOC k is the battery state of charge SOC at the k-1th moment and the kth moment, T s is the sampling interval, R p,k and C p,k are the polarization resistance and polarization capacitance at the kth moment, Cn is the battery capacity, X k-1 is the battery status at the k-1th moment, I k-1 is the current at the k-1th moment. The current is positive when the battery is discharging and negative when it is charging. k-1 is the system process noise covariance at the k-1th moment;

[0051] The observed quantity of the state equation is the battery output voltage U at the kth moment out,k , the observation equation is:

[0052]

[0053] Among them, H is the observation equation coefficient matrix, R 0,k and U OC,k are the battery ohmic internal resistance and battery open circuit voltage at the kth moment, I k is the current at the kth moment, R k-1 is the system observation noise covariance at the k-1th moment;

[0054] ii. Calculate the battery state X at the kth moment based on the battery charging current and battery voltage of the charged vehicle k A priori estimate of

[0055]

[0056] in, is the optimal estimate of the battery state at the k-1th moment;

[0057] iii. Calculate the system prior covariance P at the kth moment k|k-1 :

[0058] P k|k-1 =A k P k-1|k-1 A k T +Q k-1

[0059] Among them, P k-1|k-1 is the system prior covariance at the k-1th moment;

[0060] iv. Calculate the Kalman filter gain K at the kth moment k :

[0061] K k=P k|k-1 H T (HP k|k-1 H T +R k ) -1

[0062] Among them, R k is the system observation noise covariance at the kth moment;

[0063] v. Calculate the optimal estimate of the battery state quantity of the battery state equation at the kth moment

[0064]

[0065] The battery state includes SOC and polarization voltage. Get the SOC and polarization voltage of the battery at the kth moment;

[0066] vi. Calculate the optimal estimated covariance P at the kth moment k|k :

[0067] P k|k =(EK k H)P k|k-1

[0068] Where E is the identity matrix;

[0069] vii. Update the system process noise covariance Q at the kth moment k :

[0070]

[0071] viii. Update the system observation noise covariance R at the kth moment k :

[0072]

[0073] In step 6), the battery parameters including the battery ohmic internal resistance R0, polarization internal resistance R p and polarization capacitance C p Perform iterative updates, including the following steps:

[0074] i. The iteration formula is:

[0075]

[0076] where z k =U OC,k -U out,k

[0077] ii. Assume:

[0078]

[0079] where z k-1 =U OC,k-1 -U out,k-1 , I k-1 is the battery current at time k-1;

[0080] iii. Calculate the least squares covariance matrix P at the kth moment θ,k :

[0081]

[0082] Among them, P θ,k-1 is the least squares covariance matrix at the k-1th moment, and λ is the forgetting factor;

[0083] iv. Calculate the least squares gain matrix K at the kth moment θ,k :

[0084]

[0085] v. Calculate the battery parameter θ at the kth moment k :

[0086]

[0087] where θ k-1 is the battery parameter at the k-1th moment, including the battery ohmic internal resistance R0, polarization internal resistance R p and polarization capacitance C p , then update the battery parameters as:

[0088]

[0089] In step 7), the Kalman filter estimates the battery capacity at a macro scale and uses the battery capacity to calculate the battery health, including the following steps:

[0090] i. Macro time scale parameter initialization:

[0091] Set the initial value of battery capacity Cn0 and the initial value of capacity error covariance P Cn,0 , initial value of noise in capacity estimation process Q Cn,0 and observation

[0092] Noise initial value R Cn,0 ;

[0093] ii. Macro time scale activation:

[0094] Define the length of the macro time scale L, the micro time scale k = 1: L, L range is 80 ~ 120, when the micro time scale k = L, the macro time scale is turned on, the micro time scale k = 1, and a new round of micro time scale calculation is started; at the mth macro time scale step definition:

[0095] The state equation of the battery at the microscopic time scale: m,k =F(x m,k-1 ,Cn m )

[0096] The state equation of a macroscopic time scale battery: Cn m =Cn m-1

[0097] Observation equation: y m,k =H(x m,k-1 ,Cn m )

[0098] Among them, x m,k-1 and x m,k are the battery state quantities at the macroscopic mth stage and microscopic k-1th and kth moments, including the battery SOC and polarization voltage, obtained through step 5), y m,k is the observed value at the macroscopic stage m and microscopic moment k, Cn m-1 and Cn m Represent the battery capacity at the macroscopic m-1 and m stages respectively;

[0099] iii. Macro time scale time update:

[0100] Predict the capacity prior state of the macroscopic m-1 stage

[0101]

[0102] Predict the macroscopic m-1 stage capacity error prior covariance

[0103]

[0104] Among them, Q Cn,m-1 and P Cn,m-1 are the capacity estimation process noise and capacity error covariance of the m-1th stage, respectively;

[0105] iv. Capacity estimation observation matrix calculation:

[0106] The observation equation of the capacity estimation process is the terminal voltage U out,L Calculation formula:

[0107] U out,L =U OC,L +Up,L +R 0,L ×I L

[0108] Among them, U OC,L is the open circuit voltage, U p,L is the polarization voltage, R 0,L is the internal resistance of the battery, I L is the battery current;

[0109] The extended Kalman filter solves the estimation problem of nonlinear systems by linearizing the nonlinear system, that is, by performing Jacobian linearization on the state equation and the observation equation to obtain the Jacobian matrix of the state equation:

[0110] A Cn =1

[0111] The Jacobian matrix of the observation equation is calculated by the iterative formula:

[0112] (1) Calculate the a posteriori estimate of the capacity derivative of the state equation at the macroscopic stage m and the microscopic time k-1

[0113]

[0114] in, K m,k-1 They are the prior estimate of the capacity derivative of the state equation at the microscopic k-1 moment in the macroscopic mth stage, the capacity derivative of the observation equation, and the Kalman gain;

[0115] (2) Calculate the prior estimate of the capacity derivative of the state equation at the macroscopic stage m and the microscopic time k

[0116]

[0117] (3) Calculate the derivative of the observation equation at the macroscopic stage m and the microscopic moment k with respect to capacity

[0118]

[0119] When iterating to the microscopic time scale k = L, the iteration process is exited, and the derivative value of the observation equation at the last moment of the microscopic time scale to the capacity is the Jacobian matrix corresponding to the observation matrix required for the calculation of the next macroscopic time scale:

[0120]

[0121] m, k and L are all natural numbers;

[0122] v. Macroscopic time scale measurement update:

[0123] (1) Calculate the macroscopic Kalman gain K at the mth stage Cn,m :

[0124]

[0125] (2) Calculate the battery capacity Cn at the macroscopic mth stage m :

[0126]

[0127] (3) Calculate the error covariance P of the macroscopic mth stage Cn,m :

[0128]

[0129] vi. Online calculation of battery health SOH:

[0130] The ratio of the estimated capacity value to the initial capacity value is taken as the battery health SOH, and the battery health SOH is calculated as:

[0131]

[0132] The battery capacity estimated in step 7)v(2) at the current macroscale is input to the micro time scale in the next macroscale, and the battery capacity Cn in the state equation of the battery in step 5)i is updated for SOC and polarization voltage estimation.

[0133] In step 8), the charging stop time of the charged vehicle should meet two conditions at the same time: 1. The charged vehicle has been charged with sufficient electricity, and 2. The result of the battery health of the charged vehicle is reliable. Based on the above two points, the charging stop time determination process is as follows:

[0134] i. Determine whether the charged power reaches the required power:

[0135] When the charged power reaches the set proportion Q of the battery's initial capacity th hour:

[0136]

[0137] It is considered that condition 1 is met, and step 8) ii is executed at this time, otherwise charging continues, Q th 20% to 40%, among which, for

[0138] The battery is charged according to the accumulated ampere-hour points. Cn0 is the initial capacity;

[0139] ii. Reliability evaluation of battery health SOH:

[0140] The reliability of the estimated battery health SOH is evaluated based on two evaluation indicators: 1) The increment of the mean square error between the measured terminal voltage and the estimated terminal voltage is less than the variance increment threshold ξ th ; 2) The error between the battery health SOH′ obtained by the SOC estimation curve and the ampere-hour accumulation increment and the battery health SOH estimated by the algorithm is less than the SOH change amplitude threshold ξ SOH,th ; If evaluation indicators 1) and 2) are met at the same time, the battery health SOH result is considered reliable and charging is stopped.

[0141] The increment of the mean square error between the measured value and the estimated value of the terminal voltage at the macro time scale is used as the basic indicator of evaluation index 1), as shown in the following formula:

[0142]

[0143] Among them, U out,m,k and m,k are respectively the measured value and observed value of the terminal voltage at the microscopic kth moment in the macroscopic mth stage, and the measured value of the terminal voltage U at the microscopic kth moment in the macroscopic mth stage out,m,k Obtained by CAN communication, k = 1, 2, 3...L;

[0144] When the absolute value of the mean square error increment for 3 to 10 consecutive macro time scales is less than the variance increment threshold ξ th hour:

[0145] |ξ m -ξ m-1 |<ξ th

[0146] It is considered that the evaluation index 1) is met, and the variance increment threshold ξ th Range is 10 -5 ~10 -3 , where i = 1, 2, 3...L, Δt is the sampling time interval, ξ m and m-1 are the mean square error of terminal voltage at the mth and m-1th macroscopic time scales, respectively;

[0147] The absolute value of the difference between the two SOH results at the macro time scale is used as the basic indicator of evaluation index 2), as shown in the following formula: When the SOH difference of 3 to 10 consecutive macro scales is less than the SOH change amplitude threshold ξ SOH,th , SOH change amplitude threshold ξ SOH,th The range is 2% to 5%:

[0148]

[0149] It is considered that the evaluation index 2) is met, where the battery health SOH' calculated by the increment of the ampere-hour accumulation is as follows:

[0150]

[0151] In the formula, SOC t and SOC0 are the estimated SOC and initial SOC values ​​at this time, respectively;

[0152] If evaluation indicators 1) and 2) are met at the same time, the battery health result is considered reliable and charging is stopped.

[0153] Advantages of the present invention:

[0154] (1) The present invention provides a novel multifunctional mobile charging vehicle structure, which can not only use various charging piles to charge the charging vehicle, but also meet the charging needs of various electric vehicles through AC slow charging and DC fast charging, and can also realize the rapid detection of the health of the battery of the charged vehicle;

[0155] (2) The mobile charging vehicle system has a high degree of integration. Only one bidirectional DCDC power conversion module is needed to complete the voltage step-up and step-down operations of the mobile charging vehicle, thereby completing the charging of the high-voltage battery pack and the discharge of the charged vehicle.

[0156] (3) The present invention can realize online detection of the health of the battery on board the new energy vehicle only through the battery information of the charged vehicle and the charging process information, without the need for long-term battery life cycle test and full charge and discharge test, which greatly reduces the detection cost and detection time;

[0157] (4) The battery health detection method of the present invention combines the multi-time scale extended Kalman filter algorithm and the recursive least squares method to effectively improve the battery parameter identification and battery health detection accuracy; at the same time, the detection stop condition is set to ensure the reliability and stability of the battery health results;

[0158] (5) The mobile charging vehicle adopts integrated thermal management. The high-voltage battery pack and the bidirectional DCDC power conversion module share an outdoor heat exchanger to ensure heat dissipation of both.

[0159] (6) A non-zero current is used in the low-level stage of the square wave current excitation to ensure that the charging current of the charged vehicle is always positive during the detection period, preventing the high-power consumption of the charged vehicle's own electrical appliances from causing battery discharge, thereby avoiding the occurrence of inaccurate detection results. BRIEF DESCRIPTION OF THE DRAWINGS

[0160] Figure 1 This is a structural block diagram of a mobile charging vehicle capable of detecting battery health of the present invention;

[0161] Figure 2 This is a structural block diagram of the vehicle communication network of the mobile charging vehicle capable of detecting battery health of the present invention;

[0162] Figure 3 A schematic diagram of current excitation in a health detection mode of an embodiment of a mobile charging vehicle capable of detecting battery health of the present invention;

[0163] Figure 4 A schematic diagram of a thermal management system of an embodiment of a mobile charging vehicle capable of detecting battery health of the present invention;

[0164] Figure 5 A flow chart of an embodiment of a mobile charging vehicle capable of detecting battery health of the present invention;

[0165] Figure 6 This is a flowchart of determining when to stop charging according to an embodiment of a mobile charging vehicle capable of detecting battery health of the present invention. DETAILED DESCRIPTION

[0166] The present invention will be further described below through specific embodiments in conjunction with the accompanying drawings.

[0167] like Figure 1 As shown, the mobile charging vehicle capable of detecting battery health of the present embodiment includes: a high-voltage battery pack, a first power distribution box, a second power distribution box, a bidirectional direct current to direct current (DCDC) power conversion module, a direct current to alternating current (DCAC) power conversion module, an AC charger, an AC output socket, an AC charging socket, a first DC charging socket, a second DC charging socket, an air switch, a low-voltage power supply module, a charging start button, an emergency stop button, a DC charging gun, a thermal management system, a vehicle control module, a touch-sensitive LCD screen and a data recording module; wherein the high-voltage battery pack is connected to the bidirectional DCDC power conversion module, the AC charger, the first DC charging socket, the DCAC power conversion module and the low-voltage power supply module respectively through the first power distribution box; the bidirectional DCDC power conversion module is connected to the DC charging gun, the second DC charging socket and the thermal management system respectively through the second power distribution box; the AC charger is connected to the AC output socket; the DCAC power conversion module is connected to the AC output socket; the low-voltage power supply module is connected to the vehicle control module, the touch-sensitive LCD screen, the data recording module and the thermal management system respectively;

[0168] The vehicle control module includes a first DC charging socket control board, a second DC charging socket control board, a DC charging gun control board and a vehicle controller. The built-in communication modules of the first DC charging socket control board, the second DC charging socket control board and the DC charging gun control board are respectively connected to the communication lines of the first DC charging socket, the second DC charging socket and the DC charging gun. The first DC charging socket control board, the first DC charging socket control board, the DC charging gun control board, the vehicle controller, the high-voltage battery pack, the DCAC power conversion module, the bidirectional DCDC power conversion module, the AC charger, the data recording module, the touch-control LCD screen and the compressor and PTC heater in the thermal management system are all provided with their own communication modules and have communication functions. All these communication modules are interconnected to form a vehicle communication network of the mobile charging vehicle, such as Figure 2 As shown; the vehicle communication network includes a CAN bus communication network and an RS485 bus communication network, wherein the CAN bus communication network of the mobile charging vehicle includes a high-voltage battery pack, a first DC charging socket, a DC charging gun, a second DC charging socket, a compressor, a PTC heater, an AC charger, a data recording module and a vehicle controller; the RS485 communication network includes a first DC charging socket control board, a DC charging gun control board, a second DC charging socket control board, a bidirectional DCDC power conversion module, a DCAC power conversion module and a touch-sensitive LCD screen, Figure 2 CAN-H and CAN-L are the H line and L line of CAN communication respectively; RS485-A and RS485-B are the A line and B line of RS485 communication network respectively;

[0169] The first distribution box includes a first distribution box shell, a high-voltage battery pack interface, a bidirectional DCDC power conversion module interface, an AC charger interface, a first DC charging socket interface, a DCAC power conversion module interface, a low-voltage power supply module interface, a battery high-voltage relay, a first high-voltage relay and a second high-voltage relay; the interior of the first distribution box shell is hollow, and a high-voltage battery pack interface, a bidirectional DCDC power conversion module input interface, an AC charger interface, a first DC charging socket interface, a DCAC power conversion module interface and a low-voltage power supply module interface are respectively arranged on the surface of the first distribution box shell, and a battery high-voltage relay, a first high-voltage relay and a second high-voltage relay are arranged in the first distribution box shell; the output end of the high-voltage battery pack is connected to the high-voltage battery pack interface, and the high-voltage battery pack interface The high-voltage battery pack interface is connected to the input interface of the bidirectional DCDC power conversion module through the battery high-voltage relay and the first high-voltage relay, and the high-voltage battery pack interface is connected to the first DC charging socket interface through the battery high-voltage relay and the second high-voltage relay. The high-voltage battery pack interface is also connected to the DCAC power conversion module interface and the low-voltage power supply module interface respectively; the bidirectional DCDC power conversion module input interface is connected to the input end of the bidirectional DCDC power conversion module; the AC charger interface is connected to the AC charger; the first DC charging socket interface is connected to the first DC charging socket; the DCAC power conversion module interface is connected to the DCAC power conversion module; the low-voltage power supply module interface is connected to the low-voltage power supply module through the air switch;

[0170] The second power distribution box includes a second power distribution box housing, a bidirectional DCDC power conversion module output interface, a second DC charging socket interface, a thermal management system interface, a DC charging gun interface, a third high-voltage relay and a fourth high-voltage relay; the interior of the second power distribution box housing is hollow, and the bidirectional DCDC power conversion module output interface, the second DC charging socket interface, the thermal management system interface and the DC charging gun interface are respectively arranged on the surface of the second power distribution box housing, and the third high-voltage relay and the fourth high-voltage relay are arranged in the second power distribution box housing; the output end of the bidirectional DCDC power conversion module is connected to the bidirectional DCDC power conversion module output interface; the DCDC power conversion module output interface is connected to the second DC charging socket interface; the DCDC power conversion module output interface is connected to the DC charging gun interface through the third high-voltage relay; the DCDC power conversion module output interface is connected to the thermal management system interface through the fourth high-voltage relay; the second DC charging socket interface is connected to the second DC charging socket; the DC charging gun interface is connected to the DC charging gun through the charging start button and the emergency stop button; the thermal management system interface is connected to the compressor and thermistor (Positive Temperature Coefficient, PTC) heater in the thermal management system;

[0171] The charging and discharging modes of the mobile charging vehicle include: first DC charging mode, second DC charging mode, AC slow charging mode, fast charging mode, health detection mode and AC output mode:

[0172] In the first DC charging mode, the first DC charging socket is connected to a DC charging pile with a maximum voltage of 750v to charge the high-voltage battery pack. The vehicle controller controls the battery high-voltage relay and the second high-voltage relay to close, and the other high-voltage relays are disconnected. During the charging process, the first DC charging socket control board obtains the real-time voltage, state of charge (SOC) and maximum charging current information of the high-voltage battery pack from the vehicle communication network in real time, and completes the controller area network (CAN) communication between the mobile charging vehicle and the charging pile. The communication standard is GBT27930-2015 "Communication Protocol between Non-onboard Conductive Charger and Battery Management System of Electric Vehicles", so that the charging pile outputs current to charge the high-voltage battery pack, and uploads the information to the touch-sensitive LCD screen through the RS485 bus communication network.

[0173] In the second DC charging mode, the second DC charging socket is connected to a DC charging pile with a maximum voltage of 500v to charge the high-voltage battery pack. The vehicle controller controls the battery high-voltage relay and the fourth high-voltage relay to close, and the other high-voltage relays are disconnected. During the charging process, the second DC charging socket control board obtains the real-time voltage, SOC and maximum charging current information of the high-voltage battery pack from the vehicle communication network in real time. The maximum charging current of the second DC charging mode is the smaller value of the maximum charging current of the high-voltage battery pack and the maximum allowable current of the bidirectional DCDC power conversion module. At the same time, the voltage at the output end of the bidirectional DCDC power conversion module is controlled to be lower than the maximum voltage of the DC charging pile and maintained at a constant voltage, and then the voltage is boosted through the bidirectional DCDC power conversion module. The second DC charging socket control board obtains the real-time information of the high-voltage battery pack from the CAN bus communication network, completes the CAN communication between the mobile charging vehicle and the charging pile, and the communication standard is GBT 27930-2015, and controls the output end of the bidirectional DCDC power conversion module to maintain a constant voltage through the RS485 bus communication network, so that the charging pile outputs current to charge the high-voltage battery pack; at the same time, the information is uploaded to the touch-sensitive LCD screen through the RS485 bus communication network;

[0174] In the AC slow charging mode, the AC charging socket is connected to the AC charging pile, the vehicle controller controls the battery high-voltage relay and the first high-voltage relay to close, and the other high-voltage relays to disconnect, so as to charge the high-voltage battery pack; during the charging process, the vehicle controller is responsible for completing the confirmation of the slow charging process and outputting the slow charging current allowed at this time according to the national standard protocol; the AC charger obtains the slow charging current allowed at this time from the vehicle communication network and adjusts the voltage at the output end of the AC charger; at the same time, the vehicle controller completes the confirmation of the slow charging process according to GBT 18487.1-2015, and uploads the slow charging current allowed at this time to the CAN bus communication network; the AC charger adjusts the DC voltage at the output end to realize slow charging of the high-voltage battery pack;

[0175] In the fast charging mode, the DC charging gun is connected to the battery of the charged vehicle, and the fast charging mode is selected on the touch-sensitive LCD screen. The vehicle controller controls the battery high-voltage relay and the third high-voltage relay to close, and the other high-voltage relays are disconnected, so that the high-voltage battery pack quickly charges the charged vehicle; during the charging process, the DC charging gun control board completes the CAN communication between the mobile charging vehicle and the charged vehicle, and obtains the maximum discharge current of the high-voltage battery pack from the vehicle communication network, thereby adjusting the output voltage of the bidirectional DCDC power conversion module to control the output current. At this time, the actual output current is the smaller value of the maximum discharge current of the high-voltage battery pack and the current required by the charged vehicle, thereby realizing fast DC charging for the charged vehicle; the DC charging gun control board simulates the charging pile to complete the CAN communication with the charged vehicle, and obtains the maximum discharge current of the high-voltage battery pack from the CAN bus communication network, thereby controlling the output voltage of the bidirectional DCDC power conversion module through the RS485 bus, thereby controlling the output current. At this time, the actual output current is the smaller value of the maximum discharge current of the high-voltage battery pack and the current required by the charged vehicle, thereby realizing fast DC charging for the charged vehicle; at the same time, the information is uploaded to the touch-sensitive LCD screen through the RS485 bus communication network;

[0176] In the health detection mode, the DC charging gun is connected to the battery of the charged vehicle, and the health detection mode is selected on the touch-screen LCD screen. The vehicle controller controls the battery high-voltage relay and the third high-voltage relay to close, and the other high-voltage relays are disconnected, and the battery health of the charged vehicle is detected by a mobile charging vehicle; during the charging process, the vehicle controller adjusts the maximum discharge current of the high-voltage battery pack in real time, and the current range is 0 to the smaller value of the required current of the charged vehicle and the maximum discharge current of the high-voltage battery pack, thereby limiting the maximum output current of the DCDC power conversion module outlet, so that the charged vehicle is charged in a specific pulse current form, and its health is detected according to the voltage response of the charged vehicle; the DC charging gun control board obtains the maximum discharge current information of the high-voltage battery pack from the CAN bus communication network, simulates the charging pile to complete the CAN communication with the charged vehicle, and controls the outlet voltage of the bidirectional DCDC power conversion module through the RS485 bus to control the output current to detect the health of the battery pack of the charged vehicle. An example of current excitation for realizing battery health detection is shown in the attached figure. Figure 3 As shown; at the same time, the information is uploaded to the touch-sensitive LCD screen through the RS485 bus communication network;

[0177] In the first DC charging mode, the second DC charging mode, the AC slow charging mode, the fast charging mode and the health detection mode, the battery high voltage relay protects the high voltage battery pack from overcurrent damage during the charging and discharging process;

[0178] In AC output mode, the AC output socket is connected to the electrical appliance that needs power;

[0179] The vehicle controller controls the opening and closing of the first high-voltage relay, the second high-voltage relay, the third high-voltage relay and the fourth high-voltage relay, and at most only one of the four high-voltage relays is closed at the same time to ensure the singleness of the charging and discharging mode of the mobile charging vehicle.

[0180] like Figure 4As shown, the thermal management system includes: a compressor, an outdoor heat exchanger, a thermal expansion valve, a plate heat exchanger, a PTC heater, a first temperature sensor, a second temperature sensor, a water pump and a three-way valve; wherein, the mobile charging vehicle adopts an integrated thermal management circuit including a coolant circuit and a refrigerant circuit: in the coolant circuit, one side of the high-voltage battery pack is connected to the PTC heater through a water pipe, a first temperature sensor is arranged on the water pipe connecting the high-voltage battery pack to the PTC heater, and the PTC heater is connected to the first outlet of the three-way valve; one side of the bidirectional DCDC power conversion module is connected to the three-way valve through a pipeline The second outlet of the two-way DCDC power conversion module is connected to the second outlet of the three-way valve, and a second temperature sensor is set on the pipeline connecting the two-way DCDC power conversion module to the second outlet of the three-way valve. The other side of the high-voltage battery pack and the other side of the two-way DCDC power conversion module are connected to one side of the water pump, and the other side of the water pump is connected to the first interface of the plate heat exchanger, and the second interface of the plate heat exchanger is connected to the inlet of the three-way valve; in the refrigerant circuit, the outlet of the compressor, the outdoor heat exchanger and the inlet of the thermal expansion valve are connected in this way, the outlet of the thermal expansion valve is connected to the third interface of the plate heat exchanger, and the fourth interface of the plate heat exchanger is connected to the inlet of the compressor. The first temperature sensor, the second temperature sensor, the three-way valve and the water pump are connected to the vehicle controller of the vehicle control module through control lines respectively; the thermal management system is used to keep the high-voltage battery pack and the two-way DCDC power conversion module in a suitable operating temperature range.

[0181] The data recording module is connected to the host computer through its own communication module; it obtains the charging information of the charged vehicle from the vehicle communication network, including battery type, SOC, battery voltage, battery current, battery temperature and battery cell maximum voltage information; and stores it in the host computer to record the battery health of the charged vehicle and build a new energy vehicle charging database.

[0182] The touch-screen LCD is used to display information about the high-voltage battery pack, the bidirectional DCDC power conversion module and the vehicle control module; at the same time, the touch-screen LCD is used to set the thresholds for overvoltage warning, undervoltage warning and overtemperature warning of the bidirectional DCDC power conversion module; when the DC charging gun is connected to the charged vehicle, the touch-screen LCD is also used to display the charging information of the charged vehicle and to select different charging modes, including fast charging mode and health detection mode.

[0183] The vehicle control module includes: a vehicle controller, a first DC charging socket control board, a second DC charging socket control board, and a DC charging gun control board; the vehicle controller is used to estimate the state of the high-voltage battery pack, determine the charging and discharging mode of the mobile charging vehicle, and perform thermal management control; the vehicle controller first estimates the state of charge (State of Charge, SOC) and power state (State of Power, SOP) of the high-voltage battery pack based on the battery cell information obtained from the vehicle communication network to prevent overcharging and over-discharging of the battery, and uploads the battery pack status to the vehicle communication network; secondly, the vehicle controller determines the charging and discharging mode of the mobile charging vehicle based on the connection status of the AC charging socket, the first DC charging socket, the second DC charging socket, and the DC charging gun at this time, adjusts the maximum charging and discharging current of the high-voltage battery pack, and controls the opening and closing of the battery high-voltage relay; finally, according to the temperature of the high-voltage battery pack and the bidirectional DCDC power conversion module, the thermal management mode of the mobile charging vehicle is determined, and the working state of the thermal management system components is controlled. The thermal management mode of the mobile charging vehicle includes a single cooling mode of the high-voltage battery pack, a single cooling mode of the bidirectional DCDC power conversion module, a dual cooling mode of the high-voltage battery pack and the bidirectional DCDC power conversion module, and a single hot mode of the high-voltage battery pack.

[0184] The first DC charging socket control board is used to cooperate with the first DC charging socket to realize the first DC charging mode in the charging and discharging mode of the mobile charging vehicle; the second DC charging socket control board is used to cooperate with the second DC charging socket to realize the second DC charging mode in the charging and discharging mode of the mobile charging vehicle; the DC charging gun control board is used to cooperate with the DC charging gun to realize the fast charging mode and health detection mode in the charging and discharging mode of the mobile charging vehicle.

[0185] The mobile charging vehicle capable of detecting battery health of the present embodiment detects the battery health of the charged vehicle in the health detection mode, such as Figure 5 As shown, the following steps are included:

[0186] 1) Pre-store the SOC-open circuit voltage curves of various types of batteries in the vehicle controller, including the SOC-open circuit voltage curves of lead-acid batteries, ternary material batteries, lithium iron phosphate batteries, nickel-hydrogen batteries, lithium manganese oxide batteries, cobalt oxide batteries, polymer lithium ion batteries and lithium titanate batteries;

[0187] 2) Connect the DC charging gun of the mobile charging vehicle to the fast charging port of the vehicle being charged, select the health detection mode on the touch screen, and press the charging start button;

[0188] 3) Obtain the type and rated capacity parameters of the battery through CAN bus communication, and call the SOC-open circuit voltage curve of the corresponding type of battery from the vehicle controller;

[0189] 4) The maximum output current at the outlet of the bidirectional DCDC power conversion module is adjusted through the DC charging gun control board to control the charging current of the charged vehicle; Figure 3 As shown, the charging current consists of the following stages:

[0190] i. Initially, it is a zero current stage, which is maintained for 20 seconds to obtain the battery voltage of the vehicle being charged when powered on as the open circuit voltage;

[0191] ii. Pulse current excitation and zero current stage, used to identify the initial value of the battery parameters of the charged vehicle. The pulse current excitation magnitude is the smaller value of the required current of the charged vehicle and the 1C discharge rate of the high-voltage battery pack. The pulse duration is 10 seconds and the zero current duration is 60 seconds.

[0192] iii. Charge for 20 seconds with the charging current required by the charged vehicle, then charge with a current of 10A for 20 seconds, repeat the square wave current excitation for 5 times, then charge with a constant current for 80 seconds with the charging current required by the charged vehicle, and then continue to repeat the above excitation current for 280 seconds until the charging of the charged vehicle is completed;

[0193] 5) Obtain the battery charging current and battery voltage of the charged vehicle through the vehicle communication network, and use Kalman filtering to estimate the SOC and polarization voltage at the micro scale, which specifically includes the following steps:

[0194] i. The state equation of the battery is expressed as:

[0195]

[0196] Among them, X k is the battery state at the kth moment, A k and B k are the state equation coefficient matrices at the kth moment, U p,k-1 and U p,k are the polarization voltage at the k-1th moment and the kth moment, SOC k-1 and SOC k is the battery state of charge SOC at the k-1th moment and the kth moment, T s is the sampling interval, R p,k and C p,k are the polarization resistance and polarization capacitance at the kth moment, Cn is the battery capacity, X k-1 is the battery status at the k-1th moment, I k-1 is the current at the k-1th moment. The current is positive when the battery is discharging and negative when it is charging. k-1 is the system process noise covariance at the k-1th moment;

[0197] The observed quantity of the state equation is the battery output voltage U at the kth moment out,k, the observation equation is:

[0198]

[0199] Among them, H is the observation equation coefficient matrix, R 0,k and U OC,k are the battery ohmic internal resistance and battery open circuit voltage at the kth moment, I k is the current at the kth moment, R k-1 is the system observation noise covariance at the k-1th moment;

[0200] ii. Calculate the battery state X at the kth moment based on the battery charging current and battery voltage of the charged vehicle k A priori estimate of

[0201]

[0202] in, is the optimal estimate of the battery state at the k-1th moment;

[0203] iii. Calculate the system prior covariance P at the kth moment k|k-1 :

[0204] P k|k-1 =A k P k-1|k-1 A k T +Q k-1

[0205] Among them, P k-1|k-1 is the system prior covariance at the k-1th moment;

[0206] iv. Calculate the Kalman filter gain K at the kth moment k :

[0207] K k =P k|k-1 H T (HP k|k-1 H T +R k ) -1

[0208] Among them, R k is the system observation noise covariance at the kth moment;

[0209] v. Calculate the optimal estimate of the battery state quantity of the battery state equation at the kth moment

[0210]

[0211] The battery state variables include SOC and polarization voltage, thus obtaining the SOC and polarization voltage of the battery at the kth moment;

[0212] vi. Calculate the optimal estimated covariance P at the kth moment k|k :

[0213] P k|k =(EK k H)P k|k-1

[0214] Where E is the identity matrix;

[0215] vii. Update the system process noise covariance Q at the kth moment k :

[0216]

[0217] viii. Update the system observation noise covariance R at the kth moment k :

[0218]

[0219] 6) Since the battery ohmic internal resistance is mainly reflected in the high frequency band, while the polarization internal resistance and polarization capacitance are at a lower frequency band, the recursive least squares method is used to calculate the battery parameters including the battery ohmic internal resistance R0, polarization internal resistance R p and polarization capacitance C p Perform iterative updates:

[0220] i. The iteration formula is:

[0221]

[0222] where z k =U OC,k -U out,k

[0223] ii. Assume:

[0224]

[0225] where z k-1 =U OC,k-1 -U out,k-1 , I k-1 is the battery current at time k-1;

[0226] iii. Calculate the least squares covariance matrix P at the kth moment θ,k :

[0227]

[0228] Among them, P θ,k-1is the least squares covariance matrix at the k-1th moment, and λ is the forgetting factor;

[0229] iv. Calculate the least squares gain matrix K at the kth moment θ,k :

[0230]

[0231] v. Calculate the battery parameter θ at the kth moment k :

[0232]

[0233] where θ k-1 is the battery parameter at the k-1th moment, then the updated battery parameter is:

[0234]

[0235] 7) According to the SOC and polarization voltage of the battery obtained in step 5), the battery capacity is estimated at a macroscopic scale using Kalman filtering, comprising the following steps:

[0236] i. Macro time scale parameter initialization:

[0237] Set the initial value of battery capacity Cn0 and the initial value of capacity error covariance P Cn,0 , initial value of noise in capacity estimation process Q Cn,0 , initial value of observation noise R Cn,0 ;

[0238] ii. Macro time scale activation:

[0239] Define the length of the macro time scale L, the micro time scale k = 1: L, when the micro time scale k = L, the macro time scale is turned on, the micro time scale k = 1, and a new round of micro time scale calculation is started; at the mth macro time scale step definition:

[0240] The state equation of the battery at the microscopic time scale: m,k =F(x m,k-1 ,Cn m )

[0241] The state equation of a macroscopic time scale battery: Cn m =Cn m-1

[0242] Observation equation: y m,k =H(x m,k-1 ,Cn m )

[0243] Among them, x m,k-1 and x m,kare the battery state quantities at the macroscopic mth stage and microscopic k-1th and kth moments, including the battery SOC and polarization voltage, obtained through step 5), y m,k is the observed value at the macroscopic stage m and microscopic moment k, Cn m-1 and Cn m Represent the battery capacity at the macroscopic m-1 and m stages respectively;

[0244] iii. Macro time scale time update:

[0245] Predict the capacity prior state of the macroscopic m-1 stage

[0246]

[0247] Predict the prior covariance of the capacity error in the macroscopic m-1th stage

[0248]

[0249] Among them, Q Cn,m-1 and P Cn,m-1 are the capacity estimation process noise and capacity error covariance of the m-1th stage, respectively;

[0250] iv. Capacity estimation observation matrix calculation:

[0251] The observation equation of the capacity estimation process is the terminal voltage U out,L Calculation formula:

[0252] U out,L =U OC,L +U p,L +R 0,L ×I L

[0253] U OC,L is the open circuit voltage, U p,L is the polarization voltage, R 0,L is the internal resistance of the battery, I L is the battery current;

[0254] The extended Kalman filter solves the estimation problem of nonlinear systems by linearizing the nonlinear system, that is, by

[0255] The Jacobian linearization of the equation and the observation equation is performed to obtain the Jacobian matrix of the state equation:

[0256] A Cn =1

[0257] The Jacobian matrix of the observation equation can be calculated by the iterative formula:

[0258] (1) Calculate the a posteriori estimate of the capacity derivative of the state equation at the macroscopic stage m and the microscopic time k-1

[0259]

[0260] in, K m,k-1 They are the prior estimate of the capacity derivative of the state equation at the microscopic k-1 moment in the macroscopic mth stage, the capacity derivative of the observation equation, and the Kalman gain;

[0261] (2) Calculate the prior estimate of the capacity derivative of the state equation at the macroscopic stage m and the microscopic time k

[0262]

[0263] (3) Calculate the derivative of the observation equation at the macroscopic stage m and the microscopic moment k with respect to capacity

[0264]

[0265] When iterating to the microscopic time scale k = 100, the iteration process is exited, and the derivative value of the observation equation at the last moment of the microscopic time scale with respect to the capacity is the Jacobian matrix corresponding to the observation matrix required for the calculation of the next macroscopic time scale:

[0266]

[0267] v. Macroscopic time scale measurement update:

[0268] (1) Calculate the macroscopic Kalman gain K at the mth stage Cn,m :

[0269]

[0270] (2) Calculate the battery capacity Cn at the macroscopic mth stage m :

[0271]

[0272] (3) Calculate the error covariance P of the macroscopic mth stage Cn,m :

[0273]

[0274] vi. Online calculation of battery health SOH:

[0275] The ratio of the estimated capacity value to the initial capacity value is taken as the battery health SOH, and the battery health SOH is calculated as follows:

[0276]

[0277] The battery capacity estimated at the current macroscale is input into the microscopic time scale in the next macroscale, and the battery capacity parameters in the state equation of step 5) are updated for SOC and polarization voltage estimation.

[0278] 8) Repeat 4) to 7) until charging is completed. Figure 6 As shown, the charging stop time of the charged vehicle should meet two conditions at the same time: 1. The charged vehicle has been charged with sufficient electricity, and 2. The battery health result of the charged vehicle is reliable. Based on the above two points, the charging stop time judgment process is as follows:

[0279] i. Determine whether the charged power reaches the required power:

[0280] When the charged power reaches the set proportion Q of the battery's initial capacity th =30%

[0281]

[0282] It is considered that condition 1 is met, and 8) ii is executed. If it is not met, continue charging;

[0283] ii. Perform reliability evaluation of battery health SOH results:

[0284] The reliability of SOH is evaluated from two evaluation indicators: 1) The increment of the mean square error between the measured value and the estimated value of the terminal voltage is less than the variance increment threshold ξ th =10 -4 ; 2) The error between the SOH obtained by the SOC estimation curve and the increment of the ampere-hour accumulation and the SOH estimated by the algorithm is less than the SOH change amplitude threshold ξ SOH,th =30%.

[0285] The increment of the mean square error between the measured value and the estimated value of the terminal voltage at the macro time scale is used as the basic indicator of evaluation index 1), as shown in the following formula:

[0286]

[0287] In the formula, k=1,2,3......L.

[0288] When the absolute values ​​of the mean square error increments of five consecutive macro time scales are all less than the variance increment threshold ξ th When , the estimation result is considered to meet the evaluation index 1):

[0289] |ξ m -ξ m-1 |<10 -4

[0290] The absolute value of the difference between the two SOH results at the macro time scale is used as the basic indicator of evaluation index 2), as shown in the following formula: When the SOH difference of five consecutive macro scales is less than the SOH change amplitude threshold ξ SOH,th , it is considered to meet the evaluation index 2):

[0291]

[0292] If evaluation indicators 1) and 2) are met at the same time, the battery health result is considered reliable and charging is stopped.

[0293] Finally, it should be noted that the purpose of publishing the embodiments is to help further understand the present invention, but those skilled in the art can understand that various substitutions and modifications are possible without departing from the spirit and scope of the present invention and the appended claims. Therefore, the present invention should not be limited to the contents disclosed in the embodiments, and the scope of protection claimed by the present invention shall be subject to the scope defined in the claims.

Claims

1. A mobile charging vehicle capable of detecting battery health, characterized in that: The mobile charging vehicle capable of detecting battery health comprises: a high-voltage battery pack, a first power distribution box, a second power distribution box, a bidirectional DC-DC power conversion module, a DC-AC power conversion module, an AC charger, an AC output socket, an AC charging socket, a first DC charging socket, a second DC charging socket, an air switch, a low-voltage power supply module, a charging start button, an emergency stop button, a DC charging gun, a thermal management system, a vehicle control module, a touch-sensitive LCD screen and a data recording module; wherein the high-voltage battery pack is respectively connected to the bidirectional DCDC power conversion module, the AC charger, the first DC charging socket, the DCAC power conversion module and the low-voltage power supply module via the first power distribution box; the bidirectional DCDC power conversion module is respectively connected to the DC charging gun, the second DC charging socket and the thermal management system via the second power distribution box; the AC charger is connected to the AC output socket; the DCAC power conversion module is connected to the AC output socket; the low-voltage power supply module is respectively connected to the vehicle control module, the touch-sensitive LCD screen, the data recording module and the thermal management system; The vehicle control module includes a first DC charging socket control board, a second DC charging socket control board, a DC charging gun control board and a vehicle controller. The built-in communication modules of the first DC charging socket control board, the second DC charging socket control board and the DC charging gun control board are respectively connected to the communication lines of the first DC charging socket, the second DC charging socket and the DC charging gun. The first DC charging socket control board, the first DC charging socket control board, the DC charging gun control board, the vehicle controller, the high-voltage battery pack, the DCAC power conversion module, the bidirectional DCDC power conversion module, the AC charger, the data recording module, the touch-sensitive LCD screen and the compressor and PTC heater in the thermal management system are all provided with their own communication modules and have communication functions. All these communication modules are interconnected to form a vehicle communication network of the mobile charging vehicle. The first distribution box includes a first distribution box shell, a high-voltage battery pack interface, a bidirectional DCDC power conversion module interface, an AC charger interface, a first DC charging socket interface, a DCAC power conversion module interface, a low-voltage power supply module interface, a battery high-voltage relay, a first high-voltage relay, and a second high-voltage relay; the interior of the first distribution box shell is hollow, and the high-voltage battery pack interface, the bidirectional DCDC power conversion module input interface, the AC charger interface, the first DC charging socket interface, the DCAC power conversion module interface and the low-voltage power supply module interface are respectively arranged on the surface of the first distribution box shell, and the battery high-voltage relay, the first high-voltage relay and the second high-voltage relay are arranged in the first distribution box shell; the output end of the high-voltage battery pack is connected to the high-voltage battery pack interface, and the high-voltage battery pack interface is connected to the bidirectional DCDC power conversion module input interface through the battery high-voltage relay. The high-voltage battery pack interface is connected to the AC charger interface through the battery high-voltage relay and the first high-voltage relay, the high-voltage battery pack interface is connected to the first DC charging socket interface through the battery high-voltage relay and the second high-voltage relay, and the high-voltage battery pack interface is also connected to the DCAC power conversion module interface and the low-voltage power supply module interface respectively; the bidirectional DCDC power conversion module input interface is connected to the input end of the bidirectional DCDC power conversion module; the AC charger interface is connected to the AC charger; the first DC charging socket interface is connected to the first DC charging socket; the DCAC power conversion module interface is connected to the DCAC power conversion module; the low-voltage power supply module interface is connected to the low-voltage power supply module through the air switch; the vehicle controller is connected to the battery high-voltage relay, the first high-voltage relay and the second high-voltage relay through the control line, respectively, for controlling the opening and closing of each high-voltage relay; The second power distribution box includes a second power distribution box housing, a bidirectional DCDC power conversion module output interface, a second DC charging socket interface, a thermal management system interface, a DC charging gun interface, a third high-voltage relay and a fourth high-voltage relay; the interior of the second power distribution box housing is hollow, and the bidirectional DCDC power conversion module output interface, the second DC charging socket interface, the thermal management system interface and the DC charging gun interface are respectively arranged on the surface of the second power distribution box housing, and the third high-voltage relay and the fourth high-voltage relay are arranged in the second power distribution box housing; the output end of the bidirectional DCDC power conversion module is connected to the bidirectional DCDC power conversion module output interface; the DCDC power conversion module output interface is connected to the second DC charging socket interface; the DCDC power conversion module output interface is connected to the DC charging gun interface through the third high-voltage relay; the DCDC power conversion module output interface is connected to the thermal management system interface through the fourth high-voltage relay; the second DC charging socket interface is connected to the second DC charging socket; the DC charging gun interface is connected to the DC charging gun through the charging start button and the emergency stop button; the thermal management system interface is connected to the compressor and thermistor PTC heater in the thermal management system; the vehicle controller is connected to the third high-voltage relay and the fourth high-voltage relay through control lines, respectively, for the opening and closing of each high-voltage control relay; The charging and discharging modes of the mobile charging vehicle include: first DC charging mode, second DC charging mode, AC slow charging mode, fast charging mode, health detection mode and AC output mode: In the first DC charging mode, the first DC charging socket is connected to the DC charging pile, the vehicle controller controls the battery high-voltage relay and the second high-voltage relay to close, and the other high-voltage relays are disconnected to charge the high-voltage battery pack; during the charging process, the first DC charging socket control board obtains the real-time voltage, state of charge SOC and maximum charging current information of the high-voltage battery pack from the vehicle communication network in real time, and completes the controller area network CAN communication between the mobile charging vehicle and the charging pile; In the second DC charging mode, the second DC charging socket is connected to a DC charging pile whose maximum voltage exceeds the maximum voltage of the high-voltage battery pack. The vehicle controller controls the battery high-voltage relay and the fourth high-voltage relay to close, and the other high-voltage relays to disconnect, so as to charge the high-voltage battery pack. During the charging process, the second DC charging socket control board obtains the real-time voltage, SOC and maximum charging current information of the high-voltage battery pack from the vehicle communication network in real time. The maximum charging current of the second DC charging mode is the smaller value of the maximum charging current of the high-voltage battery pack and the maximum allowable current of the bidirectional DCDC power conversion module. At the same time, the voltage at the output end of the bidirectional DCDC power conversion module is controlled to be lower than the maximum voltage of the DC charging pile and to maintain a constant voltage, and then the voltage is boosted through the bidirectional DCDC power conversion module. In the AC slow charging mode, the AC charging socket is connected to the AC charging pile, the vehicle controller controls the battery high-voltage relay and the first high-voltage relay to close, and the other high-voltage relays to disconnect, so as to charge the high-voltage battery pack; during the charging process, the vehicle controller is responsible for completing the confirmation of the slow charging process and outputting the slow charging current allowed at this time; the AC charger obtains the slow charging current allowed at this time from the vehicle communication network and adjusts the voltage at the output end of the AC charger; In the fast charging mode, the DC charging gun is connected to the battery of the charged vehicle, and the fast charging mode is selected on the touch-screen LCD screen. The vehicle controller controls the battery high-voltage relay and the third high-voltage relay to close, and the other high-voltage relays are disconnected, so that the high-voltage battery pack quickly charges the charged vehicle. During the charging process, the DC charging gun control board completes the CAN communication between the mobile charging vehicle and the charged vehicle, and obtains the maximum discharge current of the high-voltage battery pack from the vehicle communication network, thereby adjusting the output voltage of the bidirectional DCDC power conversion module to control the output current. At this time, the actual output current is the smaller value of the maximum discharge current of the high-voltage battery pack and the required current of the charged vehicle, thereby realizing fast DC charging for the charged vehicle. In the health detection mode, the DC charging gun is connected to the battery of the charged vehicle, and the health detection mode is selected on the touch-screen LCD screen. The vehicle controller controls the battery high-voltage relay and the third high-voltage relay to close, and other high-voltage relays to disconnect. The mobile charging vehicle is used to detect the battery health of the charged vehicle. During the charging process, the vehicle controller adjusts the maximum discharge current of the high-voltage battery pack in real time, thereby limiting the maximum output current of the DCDC power conversion module outlet, so that the charged vehicle is charged in a specific pulse current form, and detects its health according to the voltage response of the charged vehicle. In the first DC charging mode, the second DC charging mode, the AC slow charging mode, the fast charging mode and the health detection mode, the battery high voltage relay protects the high voltage battery pack from overcurrent damage during the charging and discharging process; In AC output mode, the AC output socket is connected to the electrical appliance that needs power; The vehicle controller controls the opening and closing of the first high-voltage relay, the second high-voltage relay, the third high-voltage relay and the fourth high-voltage relay, and at most only one of the four high-voltage relays is closed at the same time to ensure the singleness of the charging and discharging mode of the mobile charging vehicle.

2. The mobile charging vehicle capable of detecting battery health as claimed in claim 1, characterized in that: The thermal management system includes: a compressor, an outdoor heat exchanger, a thermal expansion valve, a plate heat exchanger, a PTC heater, a first temperature sensor, a second temperature sensor, a water pump and a three-way valve; wherein the mobile charging vehicle adopts an integrated thermal management circuit including a coolant circuit and a refrigerant circuit: in the coolant circuit, one side of the high-voltage battery pack is connected to the PTC heater through a water pipe, a first temperature sensor is arranged on the water pipe connecting the high-voltage battery pack to the PTC heater, and the PTC heater is connected to the first outlet of the three-way valve; one side of the bidirectional DCDC power conversion module is connected to the The second outlet, a second temperature sensor is arranged on the pipeline connecting the bidirectional DCDC power conversion module to the second outlet of the three-way valve, the other side of the high-voltage battery pack and the other side of the bidirectional DCDC power conversion module are connected to one side of the water pump, the other side of the water pump is connected to the first interface of the plate heat exchanger, and the second interface of the plate heat exchanger is connected to the inlet of the three-way valve; in the refrigerant circuit, the outlet of the compressor, the outdoor heat exchanger and the inlet of the thermal expansion valve are connected in this way, the outlet of the thermal expansion valve is connected to the third interface of the plate heat exchanger, and the fourth interface of the plate heat exchanger is connected to the inlet of the compressor.

3. A method for implementing a mobile charging vehicle capable of detecting battery health as claimed in claim 1, characterized in that: The implementation method comprises the following steps: a) In the first DC charging mode, the first DC charging socket is connected to the DC charging pile, the vehicle controller controls the battery high-voltage relay and the second high-voltage relay to close, and the other high-voltage relays are disconnected to charge the high-voltage battery pack; during the charging process, the first DC charging socket control board obtains the real-time voltage, SOC and maximum charging current information of the high-voltage battery pack from the vehicle communication network in real time, and completes the controller area network CAN communication between the mobile charging vehicle and the charging pile; b) In the second DC charging mode, the second DC charging socket is connected to a DC charging pile whose maximum voltage exceeds the maximum voltage of the high-voltage battery pack. The vehicle controller controls the battery high-voltage relay and the fourth high-voltage relay to close to charge the high-voltage battery pack, and the other high-voltage relays are disconnected; during the charging process, the second DC charging socket control board obtains the real-time voltage, SOC and maximum charging current information of the high-voltage battery pack from the vehicle communication network in real time. The maximum charging current of the second DC charging mode is the smaller value of the maximum charging current of the high-voltage battery pack and the maximum allowable current of the bidirectional DCDC power conversion module. At the same time, the voltage at the output end of the bidirectional DCDC power conversion module is controlled to be lower than the maximum voltage of the DC charging pile and maintained at a constant voltage, and then the voltage is boosted through the bidirectional DCDC power conversion module; c) In the AC slow charging mode, the AC charging socket is connected to the AC charging pile, the vehicle controller controls the battery high-voltage relay and the first high-voltage relay to close, and the other high-voltage relays to disconnect, so as to charge the high-voltage battery pack; during the charging process, the vehicle controller is responsible for completing the confirmation of the slow charging process and outputting the slow charging current allowed at this time according to the national standard protocol; the AC charger obtains the slow charging current allowed at this time from the vehicle communication network and adjusts the voltage at the output end of the AC charger; d) In the fast charging mode, the DC charging gun is connected to the battery of the charged vehicle, and the fast charging mode is selected on the touch-screen LCD screen. The vehicle controller controls the battery high-voltage relay and the third high-voltage relay to close, and the other high-voltage relays are disconnected, so that the high-voltage battery pack quickly charges the charged vehicle; during the charging process, the DC charging gun control board completes the CAN communication between the mobile charging vehicle and the charged vehicle, and obtains the maximum discharge current of the high-voltage battery pack from the vehicle communication network, thereby adjusting the output voltage of the bidirectional DCDC power conversion module to control the output current. At this time, the actual output current is the smaller value of the maximum discharge current of the high-voltage battery pack and the required current of the charged vehicle, thereby realizing fast DC charging for the charged vehicle; e) In the health detection mode, the DC charging gun is connected to the battery of the charged vehicle, and the health detection mode is selected on the touch-screen LCD screen. The vehicle controller controls the battery high-voltage relay and the third high-voltage relay to close, and the other high-voltage relays are disconnected. The battery health of the charged vehicle is detected by a mobile charging vehicle; during the charging process, the vehicle controller adjusts the maximum discharge current of the high-voltage battery pack in real time, thereby limiting the maximum output current of the DCDC power conversion module outlet, so that the charged vehicle is charged in a specific pulse current form, and according to the voltage response of the charged vehicle, the recursive least squares method is used to iteratively update the battery parameters, and the Kalman filter algorithm is used to estimate the SOC and polarization voltage at the micro scale, and the battery capacity is estimated at the macro scale, and finally the battery health is obtained; f) In AC output mode, the AC output socket is connected to the electrical appliances that need power supply; In the first DC charging mode, the second DC charging mode, the AC slow charging mode, the fast charging mode and the health detection mode, the battery high voltage relay protects the high voltage battery pack from overcurrent damage during the charging and discharging process; The vehicle controller controls the opening and closing of the first high-voltage relay, the second high-voltage relay, the third high-voltage relay and the fourth high-voltage relay, and at most only one of the four high-voltage relays is closed at the same time to ensure the singleness of the charging and discharging mode of the mobile charging vehicle.

4. The implementation method according to claim 3, characterized in that: In step e), the battery health of the charged vehicle is detected in the health detection mode, which specifically includes the following steps: 1) Pre-store the SOC-open circuit voltage curves of various types of batteries in the vehicle controller; 2) Connect the DC charging gun of the mobile charging vehicle to the fast charging port of the vehicle being charged, select the health detection mode on the touch screen, and press the charging start button; 3) Obtain the type and rated capacity parameters of the battery, and call the SOC-open circuit voltage curve of the corresponding type of battery from the vehicle controller; 4) The maximum output current of the bidirectional DCDC power conversion module outlet is adjusted through the DC charging gun control board to control the charging current of the charged vehicle. The charging current includes the following stages: i. Initially, it is a zero current stage, so as to obtain the battery voltage of the vehicle being charged when power is turned on as the open circuit voltage; ii. Pulse current excitation and zero current phase, used to identify the initial values ​​of the battery parameters of the charged vehicle; iii. The square wave current excitation stage is used to online calculate the SOC, equivalent circuit model battery parameters and battery capacity of the battery of the charged vehicle, so as to realize the online detection of the battery health of the charged vehicle. The square wave peak value is the smaller value of the demand current of the charged vehicle and the maximum discharge current of the high-voltage battery pack, and the square wave valley value adopts a non-zero current; 5) Obtain the battery charging current and battery voltage of the charged vehicle through the vehicle communication network, and use Kalman filtering to estimate the SOC and polarization voltage at the micro scale; 6) Since the ohmic internal resistance of the battery is mainly reflected in the high frequency band, while the polarization internal resistance and polarization capacitance are at a lower frequency band, the recursive least squares method is used to iteratively update the battery parameters; 7) According to the SOC and polarization voltage of the battery obtained in step 5), the battery capacity is estimated at a macro scale using Kalman filtering, and the battery health is calculated using the battery capacity; 8) Repeat 4) to 7) and use two evaluation indicators to evaluate the reliability of the battery health. When the two evaluation indicators are met, charging is terminated.

5. The implementation method according to claim 4, characterized in that: In step 5), the Kalman filter estimates the battery SOC and polarization voltage at a microscopic scale; specifically, the following steps are included: i. The state equation of the battery is expressed as: Among them, X k is the battery state at the kth moment, A k and B k are the state equation coefficient matrices at the kth moment, U p,k-1 and U p,k are the polarization voltage at the k-1th moment and the kth moment, SOC k-1 and SOC k is the battery state of charge SOC at the k-1th moment and the kth moment, T s is the sampling interval, R p,k and C p,k are the polarization resistance and polarization capacitance at the kth moment, Cn is the battery capacity, X k-1 is the battery status at the k-1th moment, I k-1 is the current at the k-1th moment. The current is positive when the battery is discharging and negative when it is charging. k-1 is the system process noise covariance at the k-1th moment; The observed quantity of the state equation is the battery output voltage U at the kth moment out,k , the observation equation is: Among them, H is the observation equation coefficient matrix, R 0,k and U OC,k are the battery ohmic internal resistance and battery open circuit voltage at the kth moment, I k is the current at the kth moment, R k-1 is the system observation noise covariance at the k-1th moment; ii. Calculate the battery state X at the kth moment based on the battery charging current and battery voltage of the charged vehicle k A priori estimate of in, is the optimal estimate of the battery state at the k-1th moment; iii. Calculate the system prior covariance P at the kth moment k|k-1 : P k|k-1 =A k P k-1|k-1 A k T +Q k-1 Among them, P k-1|k-1 is the system prior covariance at the k-1th moment; iv. Calculate the Kalman filter gain K at the kth moment k : K k =P k|k-1 H T (HP k|k-1 H T +R k ) -1 Among them, R k is the system observation noise covariance at the kth moment; v. Calculate the optimal estimate of the battery state quantity of the battery state equation at the kth moment The battery state includes SOC and polarization voltage. Get the SOC and polarization voltage of the battery at the kth moment; vi. Calculate the optimal estimated covariance P at the kth moment k|k : P k|k =(E-K k H)P k|k-1 Where E is the identity matrix; vii. Update the system process noise covariance Q at the kth moment k : viii. Update the system observation noise covariance R at the kth moment k :

6. The implementation method according to claim 4, characterized in that: In step 6), the battery parameters including the battery ohmic internal resistance R0, polarization internal resistance R p and polarization capacitance C p Perform iterative updates, including the following steps: i. The iteration formula is: Among them k = U OC,k -U out,k ii. Assume: where z k-1 =U OC,k-1 -U out,k-1 , I k-1 is the battery current at time k-1; iii. Calculate the least squares covariance matrix P at the kth moment θ,k : Among them, P θ,k-1 is the least squares covariance matrix at the k-1th moment, and λ is the forgetting factor; iv. Calculate the least squares gain matrix K at the kth moment θ,k : v. Calculate the battery parameter θ at the kth moment k : where θ k-1 is the battery parameter at the k-1th moment, including the battery ohmic internal resistance R0, polarization internal resistance R p and polarization capacitance C p , then update the battery parameters as:

7. The implementation method according to claim 4, characterized in that: In step 7), the Kalman filter estimates the battery capacity at a macro scale and uses the battery capacity to calculate the battery health, including the following steps: i. Macro time scale parameter initialization: Set the initial value of battery capacity Cn0 and the initial value of capacity error covariance P Cn,0 , initial value of noise in capacity estimation process Q Cn,0 and the initial value of observation noise R Cn,0 ; ii. Macro time scale activation: Define the length of the macro time scale L, the micro time scale k = 1: L, when the micro time scale k = L, the macro time scale is turned on, the micro time scale k = 1, and a new round of micro time scale calculation is started; at the mth macro time scale step definition: The state equation of the battery at the microscopic time scale: m,k =F(x m,k-1 ,Cn m ) The state equation of a macroscopic time scale battery: Cn m =Cn m-1 Observation equation: y m,k =H(x m,k-1 ,Cn m ) Among them, x m,k-1 and x m,k are the battery state quantities at the macroscopic mth stage and microscopic k-1th and kth moments, including the battery SOC and polarization voltage, obtained through step 5), y m,k is the observed value at the macroscopic stage m and microscopic moment k, Cn m-1 and Cn m Represent the battery capacity at the macroscopic m-1 and m stages respectively; iii. Macro time scale time update: Predict the capacity prior state of the macroscopic m-1 stage Predict the macroscopic m-1 stage capacity error prior covariance Among them, Q Cn,m-1 and P Cn,m-1 are the capacity estimation process noise and capacity error covariance of the m-1th stage, respectively; iv. Capacity estimation observation matrix calculation: The observation equation of the capacity estimation process is the terminal voltage U out,L Calculation formula: IN out,L =U OC,L +U p,L +R 0,L ×I L Among them, U OC,L is the open circuit voltage, U p,L is the polarization voltage, R 0,L is the internal resistance of the battery, I L is the battery current; The extended Kalman filter solves the estimation problem of nonlinear systems by linearizing the nonlinear system, that is, by performing Jacobian linearization on the state equation and the observation equation to obtain the Jacobian matrix of the state equation: A Cn ＝1 The Jacobian matrix of the observation equation is calculated by the iterative formula: (1) Calculate the a posteriori estimate of the capacity derivative of the state equation at the macroscopic stage m and the microscopic time k-1 in, and K m,k-1 They are the prior estimate of the capacity derivative of the state equation at the microscopic k-1 moment in the macroscopic mth stage, the capacity derivative of the observation equation, and the Kalman gain; (2) Calculate the prior estimate of the capacity derivative of the state equation at the macroscopic stage m and the microscopic time k (3) Calculate the derivative of the observation equation at the macroscopic stage m and the microscopic moment k with respect to capacity When iterating to the microscopic time scale k = L, the iteration process is exited, and the derivative value of the observation equation at the last moment of the microscopic time scale to the capacity is the Jacobian matrix corresponding to the observation matrix required for the calculation of the next macroscopic time scale: m, k and L are all natural numbers; v. Macroscopic time scale measurement update: (1) Calculate the macroscopic Kalman gain K at the mth stage Cn,m : (2) Calculate the battery capacity Cn at the macroscopic mth stage m : (3) Calculate the error covariance P of the macroscopic mth stage Cn,m : vi. Online calculation of battery health SOH: Estimated Capacity vs. Initial Capacity The ratio of the values ​​is taken as the battery health SOH, and the battery health SOH is calculated as: The battery capacity estimated in step 7)v(2) at the current macroscale is input to the micro time scale in the next macroscale, and the battery capacity Cn in the state equation of the battery in step 5)i is updated for SOC and polarization voltage estimation.

8. The implementation method according to claim 4, characterized in that: In step 8), the charging stop time of the charged vehicle should meet two conditions at the same time:

1. The charged vehicle has been charged with sufficient electricity, and 2. The result of the battery health of the charged vehicle is reliable. Based on the above two points, the charging stop time determination process is as follows: i. Determine whether the charged power reaches the required power: When charging Reach the set ratio Q of the initial capacity of the battery th hour It is considered that condition 1 is met, and step 8) ii is executed at this time, otherwise charging continues, wherein, The amount of charge accumulated by the battery in ampere-hours Cn0 is the initial capacity; ii. Reliability evaluation of battery health SOH: The reliability of the estimated battery health SOH is evaluated based on two evaluation indicators: 1) The increment of the mean square error between the measured terminal voltage and the estimated terminal voltage is less than the variance increment threshold ξ th ; 2) The error between the battery health SOH′ obtained by the SOC estimation curve and the ampere-hour accumulation increment and the battery health SOH estimated by the algorithm is less than the SOH change amplitude threshold ξ SOH,th ; If evaluation indicators 1) and 2) are met at the same time, the battery health SOH result is considered reliable and charging is stopped.

9. The implementation method according to claim 8, characterized in that: The increment of the mean square error between the measured value and the estimated value of the terminal voltage at the macro time scale is used as the basic indicator of evaluation index 1), as shown in the following formula: Where, k = 1, 2, 3...L, U out,m,k and m,k are the measured value and observed value of the terminal voltage at the macroscopic mth stage and microscopic kth moment respectively; When the absolute values ​​of the mean square error increments of multiple consecutive macro time scales are all less than the variance increment threshold ξ th hour: |x m -x m-1 |<ξ th It is considered to meet the evaluation index 1), where i = 1, 2, 3...L, ξ m and m-1 are the mean square errors of the terminal voltages at the mth and m-1th macroscopic time scales, respectively.

10. The implementation method according to claim 8, characterized in that: The absolute value of the difference between the two SOH results at the macro time scale is used as the basic indicator of evaluation index 2). When the SOH difference of multiple consecutive macro scales is less than the SOH change amplitude threshold ξ SOH,th : It is considered that the evaluation index 2) is met, where the battery health SOH' calculated by the increment of the ampere-hour accumulation is as follows: In the formula, SOC t and SOC0 are the estimated SOC and initial SOC at this time, respectively; If evaluation indicators 1) and 2) are met at the same time, the battery health result is considered reliable and charging is stopped.

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