Quick-charging low-voltage platform high-capacity battery system for electric forklift and control method thereof

Abstract

The invention discloses a quick-charging low-voltage platform high-capacity battery system for an electric forklift, and the system comprises a battery module which is installed on the electric forklift and supplies power to the electric forklift; the box body is mounted on the electric forklift; the two charging seats are arranged outside the box body and are used for being connected with a charging gun of a charger; the electric control system is arranged in the box body, the input end of the electric control system is connected with the two charging seats, and the discharge port of the electric control system is arranged on the box body and connected with the battery module; according to the battery module, the low-temperature-rise battery cell is used, the heating value is reduced from the source in the charging process, the charging rate is improved on the premise that a liquid cooling system is not used, the double-gun charging technology can be used for a high-capacity battery, the charging current is improved, and the purpose of rapid charging is achieved.

Description

Technical Field

[0001] The present invention relates to the field of electric forklift charging, and in particular to a fast-charging low-voltage platform large-capacity battery system for electric forklifts and a control method thereof. Background Art

[0002] With the development of new energy forklifts, new energy electric forklifts are being promoted all over the country. The charging speed of forklift batteries directly affects the user experience.

[0003] Traditional low-voltage platform electric forklifts are mostly 80V voltage platforms with large battery capacity. They use traditional lithium iron phosphate batteries and most of them do not have liquid cooling systems. To prevent excessive temperature rise during charging, the charging rate is generally limited to around 0.5C. In addition, due to the current limiting of the charging gun and charging station, the charging current generally does not exceed 200A, resulting in slow charging speed and affecting the vehicle experience.

[0004] The forklift battery heating system in the existing technology usually uses electric film heating or liquid thermal heating. Although it can solve the impact of low temperature on lithium batteries, it has problems such as low heating efficiency, slow heating speed, and uneven heating. In addition, since only one heating form is used, once the heating system fails, the lithium battery can no longer be heated, and the normal operation of the lithium battery cannot be effectively guaranteed. Summary of the Invention

[0005] In response to the problems existing in the above-mentioned prior art, the present invention provides a fast-charging low-voltage platform large-capacity battery system for electric forklifts and a control method thereof. The battery module uses low-temperature rise cells to reduce heat generation at the source during the charging process, and improves the charging rate without using a liquid cooling system. For large-capacity batteries, dual-gun charging technology can be used to increase the charging current and achieve the purpose of fast charging.

[0006] To achieve the above objectives, the present invention adopts a technical solution: a fast-charging low-voltage platform large-capacity battery system for electric forklifts, comprising: The battery module is installed on the electric forklift to provide power for the electric forklift; The box is installed on an electric forklift; The two charging bases are arranged outside the box body and are used to connect to the charging gun of the charger; The electric control system is arranged inside the box, the input end of the electric control system is connected to the two charging seats, and the discharge port of the electric control system is arranged on the box and connected to the battery module.

[0007] Furthermore, the battery module uses low-temperature-rise battery cells, which have a low temperature rise during charging and discharging, and can meet the needs of high-rate charging without the need for a liquid cooling system. At the same time, a heating film is integrated on the battery module to improve the heating efficiency under low temperature conditions, so that the battery can be heated to an appropriate temperature more quickly; the battery pack in the battery module adopts a dual-parallel solution, and each parallel battery pack is charged separately, which can greatly increase the charging current, and the heat generation is significantly reduced at the same charging rate speed, which can meet the needs of high-rate current charging.

[0008] Furthermore, the battery module includes: a battery pack A and a battery pack B. The battery pack A is provided with a heating film A, and the battery pack B is provided with a heating film B. The two charging seats are charging seat A and charging seat B respectively.

[0009] Furthermore, the electronic control system includes: a BMS host, a BMS slave, a DC-DC, a charging contactor A, a charging contactor B, a shunt A, a shunt B, a fuse A, a fuse B, a charging A heating contactor, a charging B heating contactor, a heating fuse C, and a heating fuse D. The shunt A, the battery pack A, and the fuse A are connected in series to form a battery charge and discharge circuit A. The shunt B, the battery pack B, and the fuse B are connected in series to form a battery charge and discharge circuit B. The battery charge and discharge circuit A and the battery charge and discharge circuit B are connected in parallel to form a battery charge and discharge circuit group. The control ports of the charging seat A and the charging seat B are both connected to the BMS host. The positive pole on the charging seat A is connected to the positive pole of the battery charge and discharge circuit group through the charging contactor A, the negative pole on the charging seat A is connected to the negative pole of the charge and discharge circuit group, and the positive pole on the charging seat B is connected to the positive pole of the battery charge and discharge circuit group through the charging contactor B. The positive pole on the charging seat B is connected to the negative pole of the charge and discharge circuit group, the positive pole on the charging seat A is connected to the negative pole of the battery charge and discharge circuit group through the charging A heating contactor, heating fuse C, and heating film A, and the positive pole on the charging seat B is connected to the negative pole of the battery charge and discharge circuit group through the charging B heating contactor, heating fuse D, and heating film B. The DC-DC is used to connect the battery charge and discharge circuit group to power the BMS host and BMS slave, and the BMS host and BMS slave are connected for communication. The BMS host is used for controlling the charging contactor A, charging contactor B, charging A heating contactor, and charging B heating contactor, for controlling the charging seat A and charging seat B, for current detection of the shunt A, contactor adhesion detection, and for the battery pack A voltage and temperature acquisition function. The BMS slave is used for voltage and temperature acquisition of the battery pack B, for vehicle communication, and for master-slave interaction function.

[0010] Furthermore, the electronic control system also includes: a discharge contactor A, a discharge contactor B, a pre-charge contactor, a pre-charge resistor, and a discharge heating contactor. The pre-charge contactor and the pre-charge resistor are connected in series to form a pre-charge circuit. The pre-charge circuit, the discharge contactor A, and the discharge contactor B are connected in parallel to form a discharge module. One end of the discharge module is connected to the positive pole of the battery charge and discharge circuit group, and the other end is connected to the positive pole of the load of the electric forklift. The negative pole of the load is connected to the negative pole of the battery charge and discharge circuit group. The heating fuse C and the heating fuse D are connected to the positive pole of the load through the discharge heating contactor. The discharge heating contactor is connected to the BMS slave, and the discharge heating contactor is controlled to work by the BMS slave. The discharge contactor A, the discharge contactor B, and the pre-charge contactor are connected to the BMS host, and the discharge contactor A, the discharge contactor B, and the pre-charge contactor are controlled to work by the BMS host.

[0011] A control method for a fast-charging, low-voltage, and high-capacity battery system for electric forklifts. Both charging stations A and B are connected to the BMS host, which is responsible for identifying charging gun signals. The two charging stations A and B are independent of each other, enabling single-gun or dual-gun charging of the battery system. When the battery module starts charging, the charging gun auxiliary power supply supplies power to the BMS host and BMS slave, activating the BMS host and BMS slave. After the BMS host and BMS slave self-check and no faults are found, they start to detect the charging gun signal and perform control.

[0012] Furthermore, when the BMS detects that only charging station A is connected to the charging gun, it will handshake with the charger according to the national standard charging process. After the handshake is successful, it will start to close the charging contactor A. At this time, the charging gun charges the battery module. Since battery pack A and battery pack B are in parallel, the charging current of the charging gun is evenly distributed to battery pack A and battery pack B, realizing single-gun charging. When the BMS host detects that only charging base B is connected to the charging gun, it shakes hands with the charger according to the national standard charging process. After the handshake is successful, it starts to close the charging contactor B. At this time, the charging gun charges the battery module. Since battery pack A and battery pack B are in parallel, the charging current of the charging gun is evenly distributed to battery pack A and battery pack B, realizing single-gun charging.

[0013] Furthermore, when the BMS host detects that charging base A and charging base B are connected to charging guns at the same time, it shakes hands with the corresponding chargers according to the national standard charging process. After the handshake is successful, it starts to close charging contactors A and B. At this time, the two charging guns inserted in charging base A and charging base B charge the battery module at the same time. Since battery pack A and battery pack B are in parallel, the charging current is evenly distributed to battery pack A and battery pack B, realizing dual-gun charging. At this time, the charging current is twice that of single-gun charging, and fast charging is performed.

[0014] Furthermore, when the battery module is charged at a relatively low temperature, it is necessary to heat the battery module. Two temperature preset values ​​are set inside the BMS host and BMS slave. When charging, the BMS host and BMS slave respectively detect the temperature of battery pack A and battery pack B. When the temperature of battery pack A or / and battery pack B is lower than the preset temperature 1, only the charging A heating contactor and / or the charging B heating contactor are closed. At this time, the battery enters the pure heating mode, and only the battery pack A or / and battery pack B is heated without charging. When it is detected that the temperature of battery pack A and battery pack B is between preset temperature 1 and preset temperature 2, the corresponding circuit charging contactor A and charging A heating contactor or / and charging contactor B and charging B heating contactor are closed, and the charging and heating mode is entered; When it is detected that the temperature of battery pack A and battery pack B is higher than the preset temperature 2, the corresponding circuit charging contactor A or / and charging contactor B are closed to enter the pure charging mode.

[0015] Furthermore, in any heating mode, the BMS host and BMS slave will detect the temperature of battery pack A and battery pack B in real time. When the temperature reaches the corresponding temperature range, they will execute the corresponding action according to the process and enter different heating modes. This heating method has high heating efficiency and good heating uniformity. The battery module adopts a dual-parallel solution, charging each parallel module separately, which can greatly increase the charging current and significantly reduce the heat generation at the same charging rate, which can meet the high-rate current charging requirements. The beneficial effects of the present invention are as follows: the battery module reduces heat generation at the source during charging by using low-temperature rising cells, and improves the charging rate without using a liquid cooling system. The battery module adopts a dual-parallel solution, and each parallel module is charged separately, which can greatly increase the charging current, and the heat generation is significantly reduced at the same charging rate, which can meet the needs of high-rate current charging; the battery module is integrated with a heating film, which improves the heating efficiency under low temperature conditions and enables the battery to be heated to an appropriate temperature more quickly. The battery packs in the battery module adopt a dual-parallel solution, and each parallel battery pack is charged separately, which can greatly increase the charging current, and the heat generation is significantly reduced at the same charging rate, which can meet the needs of high-rate current charging; at the same time, it also meets the needs of using dual-gun charging technology for large-capacity batteries to increase the charging current and achieve the purpose of fast charging. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 It is a schematic diagram of the principle of the present invention; Figure 3 This is a schematic diagram of the charging control process of the present invention; Figure 4 This is a flow chart of the charging and heating control of the present invention; In the figure: 1. Battery pack A; 2. Battery pack B; 3. Heating film A; 4. Heating film B; 5. BMS host; 6. BMS slave; 7. DC-DC; 8. Charging contactor A; 9. Charging contactor B; 10. Shunt A; 11. Shunt B; 12. Fuse A; 13. Fuse B; 14. Charging A heating contactor; 15. Charging B heating contactor; 16. Heating fuse C; 17. Heating fuse D; 18. Discharge contactor A; 19. Discharge contactor B; 20. Pre-charge contactor; 21. Pre-charge resistor; 22. Discharge heating contactor; 23. Box; 24. Charging station A; 25. Charging station B; 26. Discharge port. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. However, it should be understood that the specific embodiments described herein are only used to illustrate the present invention and are not intended to limit the scope of the present invention.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention pertains. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0019] like Figure 1 As shown, the fast-charging low-voltage platform large-capacity battery system for electric forklifts includes: The battery module is installed on the electric forklift to provide power for the electric forklift; The box 23 is installed on an electric forklift; The two charging seats are arranged outside the box 23 and are used to connect to the charging gun of the charger; The electric control system is arranged inside the box 23 , the input end of the electric control system is connected to the two charging seats, and the discharge port 26 of the electric control system is arranged on the box 23 and connected to the battery module.

[0020] The battery module uses low-temperature-rise battery cells, which have a low temperature rise during charging and discharging. It can meet the needs of high-rate charging without the need for a liquid cooling system. At the same time, a heating film is integrated on the battery module to improve the heating efficiency under low temperature conditions, so that the battery can be heated to an appropriate temperature more quickly. The battery pack in the battery module adopts a dual-parallel solution, and each parallel battery pack is charged separately, which can greatly increase the charging current and significantly reduce the heat generation at the same charging rate, which can meet the needs of high-rate current charging.

[0021] like Figure 2As shown, the battery module includes: a battery pack A1 and a battery pack B2. The battery pack A1 is provided with a heating film A3, and the battery pack B2 is provided with a heating film B4. The two charging seats are respectively a charging seat A24 and a charging seat B25.

[0022] The electronic control system includes: BMS host 5, BMS slave 6, DC7-DC7, charging contactor A8, charging contactor B9, shunt A10, shunt B11, fuse A12, fuse B13, charging A heating contactor 14, charging B heating contactor 15, heating fuse C16, heating fuse D17, shunt A10, battery pack A1, fuse A12 are connected in series to form battery charging and discharging circuit A, shunt B11, battery pack B2, fuse The control ports of charging base A24 and charging base B25 are both connected to the BMS host 5. The positive pole on the charging base A24 is connected to the positive pole of the battery charge and discharge circuit group through the charging contactor A8, the negative pole on the charging base A24 is connected to the negative pole of the charge and discharge circuit group, and the positive pole on the charging base B25 is connected to the battery charge and discharge circuit group through the charging contactor B9. The positive pole is connected, the negative pole on the charging seat B25 is connected to the negative pole of the charge and discharge circuit group, the positive pole on the charging seat A24 is connected to the negative pole of the battery charge and discharge circuit group through the charging A heating contactor 14, the heating fuse C16, and the heating film A3, the positive pole on the charging seat B25 is connected to the negative pole of the battery charge and discharge circuit group through the charging B heating contactor 15, the heating fuse D17, and the heating film B4, DC7-DC7 is used to connect the battery charge and discharge circuit group to power the BMS host 5 and the BMS slave 6, the BMS host 5 is communicated with the BMS slave 6, the BMS host 5 is used for controlling the charging contactor A8, the charging contactor B9, the charging A heating contactor 14, and the charging B heating contactor 15, for controlling the charging seat A24 and the charging seat B25, for current detection of the shunt A10, contactor adhesion detection, for the battery pack A1 voltage and temperature collection function, the BMS slave 6 is used for voltage and temperature collection of the battery pack B2, for vehicle communication, and for master-slave interaction function.

[0023] The electronic control system also includes: discharge contactor A18, discharge contactor B19, pre-charge contactor 20, pre-charge resistor 21, and discharge heating contactor 22. The pre-charge contactor 20 and the pre-charge resistor 21 are connected in series to form a pre-charge circuit. The pre-charge circuit, discharge contactor A18, and discharge contactor B19 are connected in parallel to form a discharge module. One end of the discharge module is connected to the positive pole of the battery charge and discharge circuit group, and the other end is connected to the positive pole of the load of the electric forklift. The negative pole of the load is connected to the negative pole of the battery charge and discharge circuit group. The heating fuse C16 and the heating fuse D17 are connected to the positive pole of the load through the discharge heating contactor 22. The discharge heating contactor 22 is connected to the BMS slave 6, and the discharge heating contactor 22 is controlled by the BMS slave 6. The discharge contactor A18, discharge contactor B19, and pre-charge contactor 20 are connected to the BMS host 5, and the discharge contactor A18, discharge contactor B19, and pre-charge contactor 20 are controlled by the BMS host 5.

[0024] Shunt A10 is used to detect the current of battery charging and discharging circuit A; shunt B11 is used to detect the current of battery charging and discharging circuit B; charging A heating contactor 14 and charging B heating contactor 15 are used to control the operation of heating film A3 and heating film B4, and discharge heating contactor 22 is used to control the operation of heating film A3 and heating film B4. The discharge contactor, pre-charge contactor 20, and pre-charge resistor 21 are used for discharge control; charging contactor A8 and charging contactor B9 are used for charging control; fuse A12, fuse B13, heating fuse C16, and heating fuse D17 are used to protect the corresponding circuits. When the circuit is overloaded or short-circuited, they will cut off the current by fusing themselves to protect electrical equipment and circuits from damage.

[0025] This forklift battery system can achieve a charging current of 1.25C on a low-voltage, large-capacity battery platform, achieving fast charging without the need for a liquid cooling device.

[0026] A control method for a fast-charging low-voltage platform large-capacity battery system for electric forklifts. Both charging stations A24 and B25 are connected to the BMS host 5, which is responsible for identifying the charging gun signal. The two charging stations A24 and B25 are independent of each other, realizing single-gun or dual-gun charging of the battery system. When the battery module starts to charge, the auxiliary power supply of the charging gun supplies power to the BMS host 5 and the BMS slave 6, activating the BMS host 5 and the BMS slave 6. After the BMS host 5 and the BMS slave 6 self-check and find no fault, they start to detect the charging gun signal and perform control.

[0027] like Figure 3 As shown, during charging control: (1) When the BMS host 5 detects that only the charging base A24 is connected to the charging gun, it shakes hands with the charger according to the national standard charging process. After the handshake is successful, it starts to close the charging contactor A8. At this time, the charging gun charges the battery module. Since the battery pack A1 and the battery pack B2 are in parallel, the charging current of the charging gun is evenly distributed to the battery pack A1 and the battery pack B2, realizing single-gun charging; (2) When the BMS host 5 detects that only the charging base B25 is connected to the charging gun, it shakes hands with the charger according to the national standard charging process. After the handshake is successful, it starts to close the charging contactor B9. At this time, the charging gun charges the battery module. Since the battery pack A1 and the battery pack B2 are in parallel, the charging current of the charging gun is evenly distributed to the battery pack A1 and the battery pack B2, realizing single-gun charging.

[0028] (3) When the BMS host 5 detects that charging base A24 and charging base B25 are connected to charging guns at the same time, it shakes hands with the corresponding chargers according to the national standard charging process. After the handshake is successful, it starts to close the charging contactors A8 and B9. At this time, the two charging guns inserted in the charging bases A24 and B25 charge the battery modules at the same time. Since the battery pack A1 and the battery pack B2 are in parallel, the charging current is evenly distributed to the battery pack A1 and the battery pack B2, realizing dual-gun charging. At this time, the charging current is twice that of single-gun charging, and fast charging is performed.

[0029] like Figure 4 As shown, when charging heating control: When the battery module is charged at a relatively low temperature, it is necessary to heat the battery module. Two temperature preset values ​​are set inside the BMS host 5 and the BMS slave 6. During charging, the BMS host 5 and the BMS slave 6 respectively detect the temperature of the battery pack A1 and the battery pack B2. When the temperature of the battery pack A1 and / or the battery pack B2 is lower than the preset temperature 1, only the charging A heating contactor 14 and / or the charging B heating contactor 15 are closed. At this time, the system enters the pure heating mode, where only the battery pack A1 and / or the battery pack B2 are heated, and no charging is performed. When it is detected that the temperature of battery pack A1 and battery pack B2 is between the preset temperature 1 and the preset temperature 2, the corresponding circuit charging contactor A8 and charging A heating contactor 14 or / and charging contactor B9 and charging B heating contactor 15 are closed, and the charging and heating mode is entered; When it is detected that the temperature of the battery pack A1 and the battery pack is higher than the preset temperature 2, the corresponding circuit charging contactor A8 or / and charging contactor B9 are closed to enter the pure charging mode; In any heating mode, the BMS host 5 and the BMS slave 6 will detect the temperature of battery pack A1 and battery pack B2 in real time. When the temperature reaches the corresponding temperature range, they will perform corresponding actions according to the process and enter different heating modes. This heating method has high heating efficiency and good heating uniformity. This heating method has high heating efficiency and good heating uniformity.

[0030] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A fast-charging low-voltage platform large-capacity battery system for electric forklifts, characterized by: include: The battery module is installed on the electric forklift to provide power for the electric forklift; The box is installed on an electric forklift; The two charging bases are arranged outside the box body and are used to connect to the charging gun of the charger; The electric control system is arranged inside the box, the input end of the electric control system is connected to the two charging seats, and the discharge port of the electric control system is arranged on the box and connected to the battery module.

2. The fast-charging low-voltage platform large-capacity battery system for electric forklifts according to claim 1 is characterized in that: The battery module uses low-temperature-rise battery cells, which have a low temperature rise during charging and discharging. It can meet the needs of high-rate charging without the need for a liquid cooling system. At the same time, a heating film is integrated on the battery module to improve the heating efficiency under low temperature conditions, so that the battery can be heated to an appropriate temperature more quickly. The battery pack in the battery module adopts a dual-parallel solution, and each parallel battery pack is charged separately, which can greatly increase the charging current and significantly reduce the heat generation at the same charging rate, which can meet the needs of high-rate current charging.

3. The fast-charging low-voltage platform large-capacity battery system for electric forklifts according to claim 2 is characterized in that: The battery module includes: a battery pack A and a battery pack B. The battery pack A is provided with a heating film A, and the battery pack B is provided with a heating film B. The two charging seats are charging seat A and charging seat B respectively.

4. The fast-charging low-voltage platform large-capacity battery system for electric forklifts according to claim 3 is characterized in that: The electronic control system includes: BMS host, BMS slave, DC-DC, charging contactor A, charging contactor B, shunt A, shunt B, fuse A, fuse B, charging A heating contactor, charging B heating contactor, heating fuse C, heating fuse D. Shunt A, battery pack A, and fuse A are connected in series to form a battery charge and discharge circuit A. Shunt B, battery pack B, and fuse B are connected in series to form a battery charge and discharge circuit B. The battery charge and discharge circuit A and the battery charge and discharge circuit B are connected in parallel to form a battery charge and discharge circuit group. The control ports of charging station A and charging station B are both connected to the BMS host. The positive pole on charging station A is connected to the positive pole of the battery charge and discharge circuit group through charging contactor A. The negative pole on charging station A is connected to the negative pole of the charge and discharge circuit group. The positive pole on charging station B is connected to the positive pole of the battery charge and discharge circuit group through charging contactor B. The negative pole on the charging seat B is connected to the negative pole of the charge and discharge circuit group, and the positive pole on the charging seat A is connected to the negative pole of the battery charge and discharge circuit group through the charging A heating contactor, heating fuse C, and heating film A. The positive pole on the charging seat B is connected to the negative pole of the battery charge and discharge circuit group through the charging B heating contactor, heating fuse D, and heating film B. The DC-DC is used to connect the battery charge and discharge circuit group to power the BMS host and BMS slave, and the BMS host and BMS slave are connected for communication. The BMS host is used for controlling the charging contactor A, charging contactor B, charging A heating contactor, and charging B heating contactor, for controlling the charging seat A and charging seat B, for current detection of the shunt A, contactor adhesion detection, and for the battery pack A voltage and temperature collection function. The BMS slave is used for voltage and temperature collection of the battery pack B, for vehicle communication, and for master-slave interaction function.

5. The fast-charging low-voltage platform large-capacity battery system for electric forklifts according to claim 4 is characterized in that: The electronic control system also includes: a discharge contactor A, a discharge contactor B, a pre-charge contactor, a pre-charge resistor, and a discharge heating contactor. The pre-charge contactor and the pre-charge resistor are connected in series to form a pre-charge circuit. The pre-charge circuit, the discharge contactor A, and the discharge contactor B are connected in parallel to form a discharge module. One end of the discharge module is connected to the positive pole of the battery charge and discharge circuit group, and the other end is connected to the positive pole of the load of the electric forklift. The negative pole of the load is connected to the negative pole of the battery charge and discharge circuit group. The heating fuse C and the heating fuse D are connected to the positive pole of the load through the discharge heating contactor. The discharge heating contactor is connected to the BMS slave, and the discharge heating contactor is controlled to work by the BMS slave. The discharge contactor A, the discharge contactor B, and the pre-charge contactor are connected to the BMS host, and the discharge contactor A, the discharge contactor B, and the pre-charge contactor are controlled to work by the BMS host.

6. The method for controlling a fast-charging low-voltage platform large-capacity battery system for an electric forklift according to claim 4, characterized in that: Both charging stations A and B are connected to the BMS host, which is responsible for identifying the charging gun signal. The two charging stations A and B are independent of each other, realizing single-gun or dual-gun charging of the battery system; When the battery module starts charging, the charging gun auxiliary power supply supplies power to the BMS host and BMS slave, activating the BMS host and BMS slave. After the BMS host and BMS slave self-check and no faults are found, they start to detect the charging gun signal and perform control.

7. The control method of the fast-charging low-voltage platform large-capacity battery system for electric forklifts according to claim 6, characterized in that: When the BMS detects that only charging station A is connected to the charging gun, it will handshake with the charger according to the national standard charging process. After the handshake is successful, it will start to close the charging contactor A. At this time, the charging gun charges the battery module. Since battery pack A and battery pack B are in parallel, the charging current of the charging gun is evenly distributed to battery pack A and battery pack B, realizing single-gun charging. When the BMS host detects that only charging base B is connected to the charging gun, it shakes hands with the charger according to the national standard charging process. After the handshake is successful, it starts to close the charging contactor B. At this time, the charging gun charges the battery module. Since battery pack A and battery pack B are in parallel, the charging current of the charging gun is evenly distributed to battery pack A and battery pack B, realizing single-gun charging.

8. The control method of the fast-charging low-voltage platform large-capacity battery system for electric forklifts according to claim 6, characterized in that: When the BMS host detects that charging base A and charging base B are connected to charging guns at the same time, it shakes hands with the corresponding chargers according to the national standard charging process. After the handshake is successful, it starts to close charging contactors A and B. At this time, the two charging guns inserted in charging bases A and B charge the battery modules at the same time. Since battery pack A and battery pack B are in parallel, the charging current is evenly distributed to battery pack A and battery pack B, realizing dual-gun charging. At this time, the charging current is twice that of single-gun charging, which is fast charging.

9. The control method of the fast-charging low-voltage platform large-capacity battery system for electric forklifts according to claim 6, characterized in that: When the battery module is charged at a relatively low temperature, it needs to be heated. Two temperature preset values ​​are set inside the BMS host and BMS slave. When charging, the BMS host and BMS slave detect the temperature of battery pack A and battery pack B respectively. When the temperature of battery pack A or / and battery pack B is lower than the preset temperature 1, only the charging A heating contactor and / or the charging B heating contactor are closed. At this time, the system enters the pure heating mode, which only heats battery pack A or / and battery pack B without charging. When it is detected that the temperature of battery pack A and battery pack B is between preset temperature 1 and preset temperature 2, the corresponding circuit charging contactor A and charging A heating contactor or / and charging contactor B and charging B heating contactor are closed, and the charging and heating mode is entered; When it is detected that the temperature of battery pack A and battery pack B is higher than the preset temperature 2, the corresponding circuit charging contactor A or / and charging contactor B are closed to enter the pure charging mode; The control method of the fast-charging low-voltage platform large-capacity battery system for electric forklifts according to claim 9 is characterized in that: In any heating mode, the BMS host and BMS slave will detect the temperature of battery pack A and battery pack B in real time. When the temperature reaches the corresponding temperature range, they will execute the corresponding actions according to the process and enter different heating modes. This heating method has high heating efficiency and good heating uniformity.

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