A parallel charging circuit and method for a pure electric mining card multi-battery pack

Abstract

The invention discloses a parallel charging circuit and method for multiple battery packs of a pure electric mining truck. The circuit comprises: a parallel charging circuit for multiple battery packs; the parallel charging circuit for multiple battery packs comprises multiple battery parallel circuits and an on-board power receiving cabinet; the multiple battery parallel circuits are composed of multiple battery circuits in parallel; the battery circuit is composed of a battery pack connected in series with a contactor and a charger in sequence; the on-board power receiving cabinet comprises: a main contactor, a pre-charging contactor, a pre-charging resistor and a controller; the pre-charging contactor and the pre-charging resistor are connected in series in sequence to form a pre-charging circuit, and the main contactor is connected in parallel with the pre-charging circuit; the on-board power receiving cabinet is also provided with a controller; the beneficial effect of the invention is that: a group of batteries is connected in series with a charger, and multiple groups of circuits are connected in parallel, so that each circuit in the system is independent, each group of circuits has a separate BMS for battery management, and each group of circuits can be operated separately.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy vehicles, and in particular to a parallel charging circuit and method for a multi-battery pack of a pure electric mining card. Background Art

[0002] The current mainstream charging strategy for electric vehicles is based on the national standard, which is mostly suitable for centralized battery topology with low battery capacity requirements. This centralized structure has a single BMS managing all battery cells and modules, and the hardware measurement circuit directly connects the voltage, current, temperature, etc. of the battery pack. The charging pile is directly connected to a single BMS, and charging and information exchange are carried out according to the national standard protocol.

[0003] Although the centralized structure mentioned above simplifies management, it may limit the scalability of larger battery systems and may introduce single point failures, and is not suitable for the needs of 100-ton pure electric mining trucks.

[0004] In order to meet the needs of 100-ton pure electric mining trucks for large-capacity batteries, battery scalability, and easy addition or removal of some battery modules, a modular battery topology is adopted. A group of batteries are connected in series with the charger, and then multiple groups of circuits are connected in parallel. This way, each circuit in the system is independent, and each group of circuits has a separate BMS for battery management, and each group of circuits can be operated separately. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art; to this end, the present invention proposes a parallel charging circuit and method for a multi-battery pack of a pure electric mining card, which is used to solve the technical problem that the prior art does not take into account the possible single point failure and is difficult to manage a single battery pack.

[0006] To achieve the above object, the present invention provides a parallel charging circuit for multiple battery packs of a pure electric mining card, comprising: a parallel charging circuit for multiple battery packs;

[0007] The multi-battery parallel charging circuit includes multiple battery parallel circuits and a vehicle-mounted power receiving cabinet;

[0008] The multiple battery parallel circuits are composed of multiple battery loops connected in parallel;

[0009] The battery circuit is composed of a battery pack connected in series with a contactor and a charger;

[0010] The vehicle-mounted power receiving cabinet comprises: a main contactor, a pre-charging contactor, a pre-charging resistor and a controller;

[0011] The pre-charging contactor and the pre-charging resistor are connected in series in sequence to form a pre-charging circuit, and the main contactor is connected in parallel with the pre-charging circuit;

[0012] The vehicle-mounted power receiving cabinet is also provided with a controller.

[0013] Further: the positive electrodes of the plurality of battery parallel circuits are electrically connected to the positive electrode of the DC bus and the on-board power receiving cabinet in sequence, and then connected to the positive electrode of the gun line of the charging pile, specifically, connected to the positive electrode of the gun line of the charging pile through the pre-charging circuit in the on-board power receiving cabinet;

[0014] The negative electrode of the parallel circuit of the multiple battery groups is electrically connected to the negative electrode of the DC bus, and directly connected to the negative electrode of the gun line of the charging pile;

[0015] The charger is provided with a capacitor.

[0016] Furthermore: the controller serves as a transmission medium between the charging pile and the vehicle-mounted controller, and supports CAN and RS232 / 485 communication protocols.

[0017] The present invention also provides a parallel charging method for a multi-battery pack of a pure electric mining card, comprising: an on-board controller;

[0018] The on-board controller serves as the central management unit of the multi-battery parallel charging circuit and can exchange information with each battery circuit in the multi-battery parallel circuit separately, including: collecting battery pack data, configuring charging strategy, controlling charger start and stop, and charger power distribution.

[0019] Furthermore: the charging strategy includes: charging preparation, charging process monitoring, and control strategy for the charging end stage, so as to enable the charging pile to transmit electric energy to the charger of each battery circuit and charge multiple battery groups in parallel.

[0020] Furthermore: the charging preparation stage is to detect the charging conditions of the pure electric mining truck and the charging pile;

[0021] The inspection of the pure electric mining truck includes: the status of the charger, the battery pack, the insulation of the vehicle circuit, the water cooling unit, the pre-charge contactor and the main contactor, and the communication status of the charging pile;

[0022] The detection of charging piles includes: detection of charging line connection status, line and socket locking status, gun temperature, pile circuit insulation, water cooling unit status, main contactor status and vehicle controller communication status.

[0023] Furthermore: the charging process monitoring includes: closing the main contactor of the charging pile, precharging the voltage of the DC bus on the vehicle, closing the front switch of the battery pack, starting the charger, controlling the power distribution of the charger, and monitoring the information exchange during charging.

[0024] Further: the power distribution is specifically as follows:

[0025] The vehicle controller collects the information of the i-th battery circuit among the N battery circuits. Battery state of charge value, battery pack current requirement value of the i-th battery circuit , the voltage Vi of the battery side of the i-th group, the maximum power ratio of the charging pile n%, and the ideal power that should be allocated to each battery circuit are calculated comprehensively;

[0026] Said The battery state of charge value is the ratio of the remaining power of the battery pack to the total capacity, as shown in the following formula:

[0027] ;

[0028] in, is the initial capacity of the i-th battery circuit;

[0029] is the current power of the i-th battery circuit;

[0030] is the total capacity of each battery circuit;

[0031] The on-board controller compares the power limit ratio transmitted by the charging pile multiplied by the rated power of the charging pile with the sum of the rated charging powers of N groups of batteries, and takes the smaller power of the two as the total power given by the charging pile, that is, , determined as follows:

[0032] When ensuring that each charger is in normal operation and the BMS battery is allowed to charge, the formula for the power requirement of the i-th battery group is:

[0033] ;

[0034] in, The power required by the i-th battery group;

[0035] If the charger of group i does not operate normally or the battery does not allow charging, the required power of the corresponding group is:

[0036] ;

[0037] Total charging power required for all battery packs for:

[0038] ;

[0039] The formula for charging pile power limit is:

[0040] ;

[0041] By limiting the power of charging piles and the total charging power required for all battery packs Compare and select the minimum value as the given value of total charging power;

[0042] ;

[0043] Then according to the battery charge state value of each battery group The size of each battery circuit, the required current for charging, and the total charging power setting value match the allocation ratio. The larger it is, the smaller the allocated power is. The smaller the value, the greater the allocated power is, achieving balanced power distribution and ensuring that each battery group is fully charged at the same time. The charging and discharging power of the i-th battery group is allocated by the following formula:

[0044] ;

[0045] in, Allocate current to the i-th battery group according to the SOC ratio;

[0046] If the charger of group i does not operate normally or the battery does not allow charging, the current allocated to group i according to the soc ratio is:

[0047] ;

[0048] By distributing the current to the i-th group of batteries according to the SOC ratio and the battery pack current requirement of the i-th battery circuit Compare and select the minimum value as the actual distributed current of the i-th battery circuit;

[0049] ;

[0050] in, Actual current distribution for the i-th battery circuit;

[0051] After obtaining the actual distribution current of the i-th battery circuit, the ideal distribution power of the i-th battery can be calculated according to the battery side voltage:

[0052] ;

[0053] in, Ideally allocate power to the i-th group of batteries.

[0054] Further: the information exchange monitoring during charging includes: the vehicle-mounted controller receives the charging pile information and sends the charging pile information;

[0055] The received charging pile information includes: charging start flag, charging pile maximum output voltage, charging pile maximum output current, charging pile ready flag, charging pile current output voltage, charging pile current output current, and charging pile current cumulative charging time;

[0056] The information sent to the charging pile includes: a battery circuit charging start flag, a battery circuit ready flag, a battery circuit required charging current, a battery circuit maximum single cell voltage, a total SOC value of multiple battery circuits, and an estimated remaining charging time.

[0057] Further: the charging end stage includes: stopping the operation of the charger, opening the front-end switch of the battery pack, opening the pre-charging contactor of the pre-charging circuit, opening the main contactor of the on-board power receiving cabinet, and exchanging charging end information;

[0058] The charging end information exchange includes: the reason why the charging pile stops charging, the reason why the battery circuit stops charging, the cumulative output power of the charging pile, and the cumulative charging time of the charging pile.

[0059] The beneficial effect of the present invention is that: a group of batteries are connected in series with a charger, and multiple groups of circuits are connected in parallel, so that each circuit in the system is independent, each group of circuits has a separate BMS for battery management, and each group of circuits can be operated separately. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the embodiments of the present invention and the technical solutions in the prior art, the drawings required for use in the embodiments and the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some implementation methods recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0061] Figure 1 It is a schematic diagram of the circuit framework of the present invention;

[0062] Figure 2 A schematic diagram of the network architecture of the present invention;

[0063] Figure 3 A charging preparation strategy diagram for the present invention;

[0064] Figure 4 It is a charging process strategy diagram of the present invention;

[0065] Figure 5 This is a diagram of the charging termination strategy of the present invention. DETAILED DESCRIPTION

[0066] In order to make the purpose, technical scheme and advantages of the present invention more clearly understood, the present invention is described and illustrated below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. Based on the embodiments provided by the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the scope of protection of the present invention.

[0067] Obviously, the drawings described below are only some examples or embodiments of the present invention. For ordinary technicians in this field, the present invention can be applied to other similar scenarios based on these drawings without any creative work.

[0068] In addition, it can be understood that although the efforts made in this development process may be complex and lengthy, for ordinary technicians in the field related to the contents disclosed in the present invention, some design, manufacturing or production changes based on the technical contents disclosed in the present invention are just conventional technical means and should not be understood as the contents disclosed in the present invention are insufficient.

[0069] If not otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form a new technical solution.

[0070] See also Figure 1 , is a schematic diagram of the circuit framework of the present invention, comprising:

[0071] A multi-battery group parallel charging circuit; the multi-battery group parallel charging circuit includes multiple battery groups parallel circuits and an on-board power receiving cabinet; it is composed of multiple battery circuits in parallel; the battery circuit is composed of a battery group connected in series with a contactor and a charger; the on-board power receiving cabinet includes: a main contactor, a pre-charging contactor, a pre-charging resistor and a controller; the pre-charging contactor and the pre-charging resistor are connected in series in sequence to form a pre-charging circuit, and the main contactor is connected in parallel with the pre-charging circuit; the on-board power receiving cabinet is also provided with a controller.

[0072] Specifically:

[0073] The positive pole of the parallel circuit of multiple battery groups is electrically connected to the positive pole of the DC bus and the on-board power receiving cabinet in turn, and then connected to the positive pole of the gun line of the charging pile. Specifically, it is connected to the positive pole of the gun line of the charging pile through the pre-charging circuit in the on-board power receiving cabinet; the negative pole of the parallel circuit of multiple battery groups is electrically connected to the negative pole of the DC bus, and directly connected to the negative pole of the gun line of the charging pile; the charger is equipped with a capacitor, and the pre-charging circuit can limit the effect of the charging pile power supply on the capacitor charging current at the moment, so as to protect the charger from damage.

[0074] As the transmission medium between the charging pile and the vehicle controller, the controller supports CAN and RS232 / 485 communication protocols, communicates with the charging pile and the vehicle controller separately, converts the information of both parties and transmits it, thus realizing the information interaction between the charging pile and the vehicle controller.

[0075] See also Figures 2 to 5 , respectively, are a schematic diagram of the network architecture, a charging preparation phase strategy diagram, a charging process strategy diagram, and a charging end strategy diagram of the present invention;

[0076] A parallel charging method for a pure electric mining card multi-battery pack, comprising: an on-board controller;

[0077] As the central management unit of the multi-battery parallel charging circuit, the on-board controller can exchange information with each battery circuit in the multi-battery parallel circuit individually, including: collecting battery pack data, configuring charging strategies, controlling the start and stop of the charger, and the charger power distribution.

[0078] Specifically:

[0079] The charging strategy includes: charging preparation, charging process monitoring, and control strategy at the end of charging, which enables the charging pile to transmit power to the charger of each battery circuit and charge multiple battery groups in parallel;

[0080] The charging preparation stage is to detect the charging conditions of the pure electric mining truck and the charging pile; the on-board controller initializes all charging process parameters, confirms that the main contactor of the on-board power receiving cabinet is in the open state, the pre-charging contactor is in the open state, the vehicle is allowed to be high voltage, there is no start command on the vehicle screen, there is no start command on the pile, the gun line connection is normal, the communication with the power receiving cabinet is normal, and the pile has been initialized. The on-board controller enters the waiting state to receive the pile start command sent by the power receiving cabinet or the start command sent by the on-board display screen; the on-board power receiving cabinet and the charging pile will also initialize all charging process parameters, and check the connection status of the charging gun line, the locking status of the gun line and the gun seat, the gun temperature, the insulation of the pile circuit, the status of the water cooling unit, the status of the main contactor on the pile, the pre-charging contactor of the power receiving cabinet, the main contactor status, the communication status of the on-board controller, and the communication status between the on-board power receiving cabinet and the charging pile. After passing the test, it enters the waiting state for starting; manually click the start button on the on-board display screen or click the start button on the pile After the button is pressed, the charging pile closes the main contactor in the power receiving cabinet, transmits the high voltage through the gun line to the front end of the contactor of the on-board power receiving cabinet, and performs insulation detection on the charging pile. The detection and closing sends the highest output voltage and current message. The on-board controller receives the maximum output capacity message of the charging pile, closes the switch between multiple groups of batteries and the charger, sends a charging request signal to the battery, and performs insulation detection on the whole vehicle. After receiving the message that any group of batteries can be charged and the insulation of the whole vehicle is qualified, the whole vehicle is ready to send a message to the charging pile. After receiving the data, the charging pile sends a pre-charge closing instruction to the on-board power receiving cabinet. The on-board power receiving cabinet receives the pre-charge closing command of the charging pile, closes the pre-charge contactor, and pre-charges the DC bus on the vehicle. When the rear end voltage of the pre-charge contactor is greater than 0.9 times the front end voltage, the main contactor of the on-board power receiving cabinet is closed, and the charging readiness message is sent to the on-board power receiving cabinet and the charging pile at the same time. The charging pile and the whole vehicle complete the preparations before charging and wait to enter the charging state.

[0081] Charging process monitoring includes: closing the main contactor of the charging pile, precharging the voltage of the DC bus on the vehicle, closing the front switch of the battery pack, starting the charger, controlling the power distribution of the charger, and monitoring the information exchange during charging;

[0082] Among them, when there are N groups of battery circuits in total, the power distribution is specifically as follows:

[0083] The vehicle controller collects the information of the i-th battery circuit (i∈N) among the N battery circuits. Battery state of charge value, battery pack current requirement value of the i-th battery circuit , the voltage Vi of the battery side of the i-th group, the maximum power ratio of the charging pile n%, and the ideal power that should be allocated to each battery circuit are calculated comprehensively;

[0084] Said The battery state of charge value is the ratio of the remaining power of the battery pack to the total capacity, as shown in the following formula:

[0085] ;

[0086] in, is the initial capacity of the i-th battery circuit;

[0087] is the current power of the i-th battery circuit;

[0088] is the total capacity of each battery circuit;

[0089] The on-board controller compares the power limit ratio transmitted by the charging pile multiplied by the rated power of the charging pile with the sum of the rated charging powers of N groups of batteries, and takes the smaller power of the two as the total power given by the charging pile, that is, , determined as follows:

[0090] When ensuring that each charger is in normal operation and the BMS battery is allowed to charge, the formula for the power requirement of the i-th battery group is:

[0091] ;

[0092] in, The power required by the i-th battery group;

[0093] If the charger of group i does not operate normally or the battery does not allow charging, the required power of the corresponding group is:

[0094] ;

[0095] Total charging power required for all battery packs for:

[0096] ;

[0097] The formula for charging pile power limit is:

[0098] ;

[0099] By limiting the power of charging piles and the total charging power required for all battery packs Compare and select the minimum value as the given value of total charging power;

[0100] ;

[0101] Then according to the battery charge state value of each battery group The size of each battery circuit, the required current for charging, and the total charging power setting value match the allocation ratio. The larger it is, the smaller the allocated power is. The smaller the value, the greater the allocated power is, achieving balanced power distribution and ensuring that each battery group is fully charged at the same time. The charging and discharging power of the i-th battery group is allocated by the following formula:

[0102] ;

[0103] in, Allocate current to the i-th battery group according to the SOC ratio;

[0104] If the charger of group i does not operate normally or the battery does not allow charging, the current allocated to group i according to the soc ratio is:

[0105] ;

[0106] By distributing the current to the i-th group of batteries according to the SOC ratio and the battery pack current requirement of the i-th battery circuit Compare and select the minimum value as the actual distributed current of the i-th battery circuit;

[0107] ;

[0108] in, Actual current distribution for the i-th battery circuit;

[0109] After obtaining the actual distribution current of the i-th battery circuit, the ideal distribution power of the i-th battery can be calculated according to the battery side voltage:

[0110] ;

[0111] in, Ideally allocate power to the i-th group of batteries.

[0112] The information exchange monitoring during charging includes: the vehicle controller receives the charging pile information and sends the information to the charging pile;

[0113] The received information includes: charging start flag, charging pile maximum output voltage, charging pile maximum output current, charging pile ready flag, charging pile current output voltage, charging pile current output current, and charging pile current cumulative charging time; the sent information includes: battery circuit charging start flag, battery circuit ready flag, battery circuit required charging current, battery circuit maximum single cell voltage, total SOC value of multiple battery circuits, and estimated remaining charging time;

[0114] Charging stage: After the on-board controller receives the message that the charging pile is ready, it sends a start-up command to the charger of the battery group circuit that is allowed to charge, and implements the current balancing charging strategy to allocate charging current to each battery group; during the charging process, the on-board controller and the charging pile continuously exchange information through the transmission of the on-board power receiving cabinet. The on-board controller sends the required voltage, current, maximum single cell voltage, current SOC, and estimated remaining charging time messages, and at the same time receives the current output voltage, current and cumulative charging time messages of the charging pile; during the charging process, it can be divided into two shutdown modes, active shutdown of the charging pile and active shutdown of the vehicle. Active shutdown of the charging pile includes manual shutdown by clicking the stop button of the charging pile and shutdown due to fault. The charging pile sends an active shutdown message to the on-board controller; active shutdown of the vehicle includes manual shutdown by clicking the stop button on the on-board display screen, shutdown due to full power and shutdown due to fault. The on-board controller sends an active shutdown message to the charging pile; When either of the two shutdown modes occurs, the charging ends.

[0115] The final charging end stage includes: stopping the charger, opening the front switch of the battery pack, opening the pre-charging contactor of the pre-charging circuit, opening the main contactor of the on-board power receiving cabinet, and exchanging charging end information; the charging end information exchange includes: the reason why the charging pile stops charging, the reason why the battery circuit stops charging, the cumulative output power of the charging pile, and the cumulative charging time of the charging pile;

[0116] End of charging: The on-board controller controls the battery groups corresponding to each charger to allocate power to 0, opens the switch between the charger and the corresponding battery group according to the message instruction, exits the charging process after receiving the cumulative output power and cumulative charging time message transmitted by the on-board controller, and waits for the charging pile and the on-board power receiving cabinet to exit the charging process; the charging pile sends the cumulative output power and cumulative charging time message to the on-board controller, and controls the on-board power receiving cabinet to open the main contactor of the on-board power receiving cabinet, and at the same time opens the main contactor in the charging pile, the on-board power receiving cabinet and the charging pile exit the charging process and complete the charging.

[0117] The above is a very detailed description of one or more embodiments of the present invention, but the content is only a specific example of the present invention and cannot be considered to limit the scope of application of the present invention. Any other methods and changes proposed based on the content of the present invention should fall within the scope of patent protection of the present invention.

Claims

1. A parallel charging method for a pure electric mining card multi-battery pack, characterized in that: include: On-board controller; The on-board controller, as the central management unit of the multi-battery parallel charging circuit, can exchange information with each battery circuit in the multi-battery parallel circuit separately, including: collecting battery pack data, configuring charging strategy, controlling charger start and stop and charger power distribution; The power distribution is specifically as follows: The vehicle controller collects the information of the i-th battery circuit among the N battery circuits. Battery state of charge value, battery pack current requirement value of the i-th battery circuit , the voltage Vi of the battery side of the i-th group, the maximum power ratio of the charging pile n%, and the ideal power that should be allocated to each battery circuit are calculated comprehensively; Said The battery state of charge value is the ratio of the remaining power of the battery pack to the total capacity, as shown in the following formula: ； in, is the initial capacity of the i-th battery circuit; is the current power of the i-th battery circuit; is the total capacity of each battery circuit; The on-board controller compares the data of the charging pile's rated power ratio multiplied by the charging pile's rated power with the sum of the rated charging powers of N groups of batteries, and takes the smaller power of the two as the total power given by the charging pile, that is, , determined as follows: When ensuring that each charger is in normal operation and the BMS battery is allowed to charge, the formula for the power requirement of the i-th battery group is: ； in, The power required by the i-th battery group; If the charger of group i does not operate normally or the battery does not allow charging, the required power of the corresponding group is: ； Total charging power required for all battery packs for: ； The formula for charging pile power limit is: ； By limiting the power of charging piles and the total charging power required for all battery packs Compare and select the minimum value as the given value of total charging power; ； Then according to the battery charge state value of each battery group The size of each battery circuit, the required current for charging, and the total charging power setting value match the allocation ratio. The larger it is, the smaller the allocated power is. The smaller the value, the greater the allocated power is, achieving balanced power distribution and ensuring that each battery group is fully charged at the same time. The charging and discharging power of the i-th battery group is allocated by the following formula: ； in, Allocate current to the i-th battery group according to the SOC ratio; If the charger of group i does not operate normally or the battery does not allow charging, the current allocated to group i according to the soc ratio is: ； By distributing the current to the i-th group of batteries according to the SOC ratio and the battery pack current requirement of the i-th battery circuit Compare and select the minimum value as the actual distributed current of the i-th battery circuit; ； in, Actual current distribution for the i-th battery circuit; After obtaining the actual distribution current of the i-th battery circuit, the ideal distribution power of the i-th battery can be calculated according to the battery side voltage: ； in, Ideally allocate power to the i-th group of batteries.

2. A parallel charging method for a pure electric mining card multi-battery pack according to claim 1, characterized in that: The charging strategy includes: charging preparation, charging process monitoring, and control strategy for the charging end stage, so as to enable the charging pile to transmit electric energy to the charger of each battery circuit and charge multiple battery groups in parallel.

3. A parallel charging method for a pure electric mining card multi-battery pack according to claim 2, characterized in that: The charging preparation stage is to detect the charging conditions of the pure electric mining truck and the charging pile; The inspection of the pure electric mining truck includes: the status of the charger, the battery pack, the insulation of the vehicle circuit, the water cooling unit, the pre-charge contactor and the main contactor, and the communication status of the charging pile; The detection of charging piles includes: detection of charging gun line connection status, gun line and gun seat locking status, gun temperature, pile circuit insulation, water cooling unit status, main contactor status and vehicle controller communication status.

4. A parallel charging method for a pure electric mining card multi-battery pack according to claim 2, characterized in that: The charging process monitoring includes: closing the main contactor of the charging pile, precharging the voltage of the DC bus on the vehicle, closing the front switch of the battery pack, starting the charger, controlling the power distribution of the charger, and monitoring the information exchange during charging.

5. A parallel charging method for a pure electric mining card multi-battery pack according to claim 4, characterized in that: The information exchange monitoring during charging includes: the vehicle controller receives the charging pile information and sends the charging pile information; The received charging pile information includes: charging start flag, charging pile maximum output voltage, charging pile maximum output current, charging pile ready flag, charging pile current output voltage, charging pile current output current, and charging pile current cumulative charging time; The information sent to the charging pile includes: a battery circuit charging start flag, a battery circuit ready flag, a battery circuit required charging current, a battery circuit maximum single cell voltage, a total SOC value of multiple battery circuits, and an estimated remaining charging time.

6. A parallel charging method for a pure electric mining card multi-battery pack according to claim 2, characterized in that: The charging end stage includes: stopping the charger, opening the front switch of the battery pack, opening the pre-charging contactor of the pre-charging circuit, opening the main contactor of the on-board power receiving cabinet, and exchanging charging end information; The charging end information exchange includes: the reason why the charging pile stops charging, the reason why the battery circuit stops charging, the cumulative output power of the charging pile, and the cumulative charging time of the charging pile.

7. A parallel charging method for pure electric mining card multi-battery pack according to claim 1, characterized in that: The multi-battery parallel charging circuit includes multiple battery parallel circuits and a vehicle-mounted power receiving cabinet; The multiple battery parallel circuits are composed of multiple battery loops connected in parallel; The battery circuit is composed of a battery pack connected in series with a contactor and a charger; The vehicle-mounted power receiving cabinet comprises: a main contactor, a pre-charging contactor, a pre-charging resistor and a controller; The pre-charging contactor and the pre-charging resistor are connected in series in sequence to form a pre-charging circuit, and the main contactor is connected in parallel with the pre-charging circuit; The vehicle-mounted power receiving cabinet is also provided with a controller.

8. A parallel charging method for a pure electric mining card multi-battery pack according to claim 7, characterized in that: The positive electrodes of the multiple battery parallel circuits are electrically connected to the positive electrode of the DC bus and the on-board power receiving cabinet in turn, and then connected to the positive electrode of the gun line of the charging pile, specifically, connected to the positive electrode of the gun line of the charging pile through the pre-charging circuit in the on-board power receiving cabinet; The negative electrode of the parallel circuit of the multiple battery groups is electrically connected to the negative electrode of the DC bus, and directly connected to the negative electrode of the gun line of the charging pile; The charger is provided with a capacitor.

9. A parallel charging method for pure electric mining card multi-battery pack according to claim 7, characterized in that: The controller serves as a transmission medium between the charging pile and the vehicle controller, and supports CAN and RS232 / 485.

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