A charging and discharging device and a control method thereof

Abstract

The application discloses a kind of charging and discharging device and control method thereof, belong to pure electric engineering machinery energy supplement field, charging and discharging device includes mobile bearing unit, mobile bearing unit is detachably installed with platform assembly, platform assembly is provided with electrical assembly and thermal management system;Electrical assembly is used for electrical energy storage, electrical energy input and output conversion and electrical energy monitoring;Thermal management system is connected with electrical assembly, for monitoring and controlling the temperature of electrical assembly.Through setting mobile bearing unit, the mobility of the device is realized, the use limit of traditional charging equipment in remote areas is solved, and the outdoor work scene of small-tonnage pure electric excavator is adapted, and the platform assembly is detachably installed on the mobile bearing unit, when the work area that the mobile bearing unit cannot pass is encountered, the module formed by the mobile bearing unit, the platform assembly, the electrical assembly and the thermal management system can be disassembled, and the module is transported, and the adaptability to different work environments is improved.

Description

Technical Field

[0001] This invention belongs to the field of energy replenishment for pure electric engineering machinery, specifically, it relates to a charging and discharging device and its control method. Background Technology

[0002] The country is strongly encouraging the development of new energy, and the market share of new energy vehicles in the passenger car sector has increased significantly. This trend has also driven the transformation of construction machinery towards new energy electrification, among which pure electric excavators have developed rapidly due to their advantages of energy saving and environmental protection.

[0003] However, limited by their range, the tonnage of pure electric excavators is generally below 22 tons, with most concentrated below 7 tons, primarily 5-ton and 2-ton models. Compared to traditional fuel-powered excavators, while pure electric excavators better meet environmental and energy-saving requirements, their range is still inferior. Furthermore, the coverage of charging stations in China is far less than that of traditional gas stations, and excavators often operate in remote areas, further exacerbating the charging difficulties of pure electric excavators. This low charging efficiency leads to widespread user concerns about the range of pure electric excavators, a situation that has become a significant obstacle to the widespread adoption of new energy excavators.

[0004] In view of the above, this application is hereby submitted. Summary of the Invention

[0005] The technical problem to be solved by this invention is to overcome the shortcomings of the prior art and provide a charging and discharging device and its control method. This invention is achieved through the following technical solution:

[0006] A charging and discharging device includes a mobile support unit on which a platform assembly is detachably mounted, and an electrical assembly and a thermal management system are provided on the platform assembly.

[0007] The electrical assembly is used for energy storage, energy input / output conversion, and energy monitoring;

[0008] The thermal management system is connected to the electrical assembly and is used to monitor and control the temperature of the electrical assembly.

[0009] Preferably, the platform assembly includes a platform base, which is mounted on the mobile support unit. A bracket is mounted on the platform base, and protective plates are mounted on the perimeter and top of the bracket. The bottom of the protective plates is fixed to the platform base.

[0010] The electrical assembly includes a first electrical component and a second electrical component. The first electrical component is mounted on the bracket, the second electrical component is mounted on the protective plate, and the thermal management system is mounted on the platform base.

[0011] Preferably, the electrical assembly includes:

[0012] A DC-DC converter is used to convert stable voltage to DC voltage.

[0013] The battery system is communicatively connected to the DC-DC converter and is used for energy storage, charging, and discharging.

[0014] The storage battery is communicatively connected to the DC-DC converter and the battery system via a power switch. The power switch is used to control the start and stop of the charging and discharging device, and the storage battery provides power to the charging and discharging device.

[0015] The charging dock assembly is communicatively connected to the battery system and is used to charge the battery system when in conjunction with an external power supply device.

[0016] The charging gun assembly is communicatively connected to the DC-DC converter. The charging gun assembly is used by the battery system to charge the device to be charged when it is used in conjunction with the device to be charged.

[0017] The controller is communicatively connected to the DC-DC converter, the battery system, the storage battery, and the thermal management system. The controller is used to control whether the battery system and the thermal management system are working.

[0018] The first electrical component includes the DC-DC converter, the battery pack of the battery system, and the high-voltage box; the second electrical component includes the controller, the charging dock assembly, and the charging gun assembly.

[0019] The charging and discharging control method of the present invention is applied in a charging and discharging device; comprising:

[0020] Acquire the working mode signal of the charging and discharging device, and control the charging and discharging device to enter the working mode corresponding to the working mode signal according to the working mode signal. The working mode includes external power replenishment mode and self-power replenishment mode.

[0021] When the charging and discharging device is in the external power replenishment mode, after the charging and discharging device is connected to the device to be replenished, the charging and discharging device is controlled to form a discharge circuit with the device to be replenished, so as to perform gradient discharge on the device to be replenished.

[0022] When the charging and discharging device is in the self-charging mode, after an external charging device is connected to the charging and discharging device, the charging and discharging device is controlled to form a charging circuit with the external charging device to perform gradient charging on the charging and discharging device.

[0023] Preferably, controlling the charging / discharging device to form a discharge circuit with the device to be recharged, so as to perform gradient discharge on the device to be recharged, includes:

[0024] The device to be recharged is subjected to gradient discharge based on the actual temperature of the battery pack in the battery system of the charging and discharging device and the preset charging temperature range.

[0025] Preferably, the preset charging temperature range includes multiple temperature intervals, including a first temperature interval, a second temperature interval, ..., an Nth temperature interval, wherein the temperatures from the first temperature interval to the Nth temperature interval increase in a gradient. The gradient discharge of the device to be recharged based on the actual temperature of the battery pack in the charging and discharging device and the preset charging temperature range includes:

[0026] When the actual temperature of the battery pack is within the first temperature range, the percentage of charging power of the charging and discharging device is controlled to gradually increase from 0% to a first preset value as the temperature of the battery pack increases.

[0027] When the actual temperature of the battery pack is within the second temperature range, the charging power percentage of the charging and discharging device is controlled to remain at the first preset value as the temperature of the battery pack increases;

[0028] When the actual temperature of the battery pack is within the third temperature range, the percentage of charging power of the charging and discharging device is controlled to gradually increase from the first preset value to the second preset value as the temperature of the battery pack increases, wherein the first preset value is less than the second preset value.

[0029] When the actual temperature of the battery pack is within the fourth temperature range, the charging power percentage of the charging and discharging device is controlled to remain at the second preset value as the temperature of the battery pack increases;

[0030] And so on.

[0031] Preferably, during the discharge or charging process, the charging control method further includes:

[0032] Detect the actual temperature of the battery pack;

[0033] When the actual temperature of the battery pack is within the preset charging temperature range, charging or discharging continues;

[0034] When the actual temperature of the battery pack is lower than the first threshold, the thermal management system is controlled to heat the battery pack, and at the same time, it is detected whether the actual temperature of the battery pack is rising. If the temperature of the battery pack rises, the thermal management system is controlled to continue heating the battery pack. If the actual temperature of the battery pack does not rise, the display is controlled to alarm and charging or discharging is stopped. The first threshold is lower than or equal to the lowest value of the preset charging range.

[0035] When the actual temperature of the battery pack is greater than the second threshold, the thermal management system is controlled to cool the battery pack, and at the same time, it is detected whether the actual temperature of the battery pack has decreased. If the actual temperature of the battery pack decreases, the thermal management system is controlled to continue cooling the battery pack and the charging and discharging device reduces the charging and discharging power. If the actual temperature of the battery pack does not decrease, the display is controlled to alarm and charging or discharging is stopped. The second threshold is higher than or equal to the highest value of the preset charging range.

[0036] Preferably, during the discharge or charging process of the charging and discharging device, the charging control method further includes:

[0037] The SOC value of the battery pack and the SOC value of the device to be recharged are detected;

[0038] When the SOC value of the battery pack is greater than or equal to the preset power value and the SOC value of the device to be recharged is not fully charged, charging continues; otherwise, charging stops.

[0039] Preferably, before the charging / discharging device begins discharging or charging, the charging control method further includes:

[0040] The insulation resistance values ​​between the positive and negative terminals of the charging gun assembly of the charging and discharging device and the ground are detected by the insulation tester of the charging and discharging device.

[0041] Determine whether the insulation resistance value meets the preset safety threshold;

[0042] If the insulation resistance value meets the preset safety threshold, the contactor in the high voltage box of the battery system and the contactor in the DC-DC converter are closed during discharge, or the contactor in the high voltage box is closed during charging, so as to form a discharge circuit or a charging circuit.

[0043] If the insulation resistance value does not meet the preset safety threshold, the control display will alarm and display fault information.

[0044] Preferably, the charging control method includes the following steps:

[0045] Obtain the signal from the power switch;

[0046] When the power switch signal is an off signal, the charging and discharging device is controlled to enter a sleep mode;

[0047] When the power switch signal is an on signal, the charging and discharging device is controlled to perform a self-test. If the self-test of the charging and discharging device is normal, the operating mode signal of the charging and discharging device is acquired.

[0048] The self-test control of the charging and discharging device includes: the self-test process of the DC converter and the self-test process of the battery power.

[0049] When the self-test result of the DC converter is abnormal, the control display alarms and displays fault information;

[0050] When the self-test result of the DC converter is normal, a self-test of the battery power is performed.

[0051] The self-check process for the battery's power level includes:

[0052] Detect the battery's charge level;

[0053] When the battery charge is greater than or equal to a preset charge threshold, the main contactor of the DC-DC converter is closed and the auxiliary contactor is opened, and all the electrical energy of the charging and discharging device is discharged to the outside.

[0054] When the battery charge is less than the preset charge threshold, the main contactor and the auxiliary contactor of the DC-DC converter are closed. The charging and discharging device discharges a first preset proportion of electrical energy to the outside and a second preset proportion of electrical energy to replenish the battery through the DC converter until the battery charge is greater than or equal to the preset charge threshold.

[0055] Compared with the prior art, the beneficial effects of the present invention are:

[0056] 1. By setting up a mobile carrier unit, the device achieves mobility, which solves the limitations of traditional charging equipment in remote areas and adapts to the outdoor operation scenarios of small-tonnage pure electric excavators. At the same time, the platform assembly can be detached and installed on the mobile carrier unit. When encountering work areas that the mobile carrier unit cannot pass through, the platform assembly can be disassembled and moved separately. The platform assembly integrates the electrical assembly and thermal management system to realize the integration of energy storage, conversion, monitoring and temperature control, ensuring the complete and efficient collaboration of the charging and discharging device and improving its adaptability to different working environments.

[0057] 2. Through the design of the mobile carrier unit's body, tires, and chassis assembly, the device can be towed on rural roads or hoisted in mountainous areas, overcoming the problem of limited mobility of large charging vehicles and enhancing the device's mobility in complex terrain.

[0058] 3. Through the combined design of the platform base, bracket, and protective plate, modular installation of the electrical assembly and thermal management system is achieved, simplifying the assembly process and facilitating later maintenance. The sealing design of the protective plate is waterproof and dustproof, effectively protecting the electrical assembly and improving the durability of the device in harsh environments. The fixing method of the bracket and the platform base enhances structural stability and ensures reliable connection of components during the movement and operation of the device. Attached Figure Description

[0059] The accompanying drawings, as part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments and descriptions of the invention are used to explain the invention, but do not constitute an undue limitation of the invention. Obviously, the drawings described below are merely some embodiments, and those skilled in the art can obtain other drawings based on these drawings without creative effort. In the drawings:

[0060] Figure 1 This is a schematic diagram of the charging and discharging device of the present invention;

[0061] Figure 2 This is a schematic diagram of the installation structure of the present invention;

[0062] Figure 3 This is a schematic diagram of the housing structure of the present invention;

[0063] Figure 4 This is a schematic diagram of the platform assembly structure of the present invention;

[0064] Figure 5 This is a schematic diagram of the interactive structure of the present invention;

[0065] Figure 6 This is a top view of the structure of the present invention;

[0066] Figure 7 This is a schematic diagram of the explosive disassembly of the present invention;

[0067] Figure 8 This is a schematic diagram of the electrical assembly structure of the present invention;

[0068] Figure 9 This is a schematic diagram of the mode control process of the present invention;

[0069] Figure 10 This is a schematic diagram of the temperature control process of the present invention;

[0070] Figure 11 This is a schematic diagram of the battery power control process of the present invention;

[0071] Figure 12 This is a schematic diagram showing the correspondence between temperature control and charging power in this invention.

[0072] In the diagram: 1. Vehicle body; 2. Electrical assembly; 3. Platform assembly; 4. Water-cooling assembly; 5. Tires; 6. Chassis assembly; 7. DC-DC converter; 8. DC converter; 9. Battery system; 10. Controller; 11. Display; 12. Vehicle-side charging communication controller; 13. Charging communication protocol converter; 14. Power switch; 15. Charging socket assembly; 16. Charging gun assembly; 17. Vehicle wiring harness; 18. Battery; 19. Battery pack; 20. Battery management system; 21. High voltage. 21. Box; 22. Battery high-voltage wiring harness; 23. Battery low-voltage wiring harness; 24. Charging high-voltage wiring harness; 25. Charging base; 26. Charging low-voltage wiring harness; 27. Charging gun; 28. Discharging high-voltage wiring harness; 29. ​​Discharging low-voltage wiring harness; 30. Platform base; 31. Machine cover; 32. Protective plate; 33. Bracket; 34. Water-cooled unit; 35. PTC heater; 36. Water pipe; 37. Expansion tank; 38. Insulation tester; 39. Front baffle; 40. Rear baffle; 41. Side baffle; 42. Top baffle.

[0073] It should be noted that these accompanying drawings and textual descriptions are not intended to limit the scope of the invention in any way, but rather to illustrate the concept of the invention to those skilled in the art by referring to specific embodiments. Detailed Implementation

[0074] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments will be clearly and completely described below with reference to the accompanying drawings. The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0075] In the description of this invention, it should be noted that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0076] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0077] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0078] The present invention will now be further described in conjunction with the accompanying drawings.

[0079] Example 1

[0080] like Figure 1 – Figure 8 As shown, this embodiment provides a charging and discharging device, including a mobile support unit, on which a platform assembly 3 is detachably mounted. An electrical assembly 2 and a thermal management system are provided on the platform assembly 3. The electrical assembly 2 is used for energy storage, energy input / output conversion and energy monitoring. The thermal management system is connected to the electrical assembly 2 and is used to monitor and control the temperature of the electrical assembly 2.

[0081] By setting up a mobile carrier unit to achieve the mobility of the device, the limitations of traditional charging equipment in remote areas are solved, making it suitable for outdoor operation scenarios of small-tonnage pure electric excavators. At the same time, the platform assembly 3 can be detached and installed on the mobile carrier unit. When encountering work areas that the mobile carrier unit cannot pass through, the modules formed by the mobile carrier unit, the platform assembly 3, the electrical assembly 2, and the thermal management system can be disassembled and transported in modules. The platform assembly 3 integrates the electrical assembly 2 and the thermal management system to achieve integrated energy storage, conversion, monitoring, and temperature control, ensuring the complete and efficient collaboration of the charging and discharging device and improving its adaptability to different working environments.

[0082] Example 2

[0083] like Figure 1 – Figure 3 As shown, the mobile carrier unit in this embodiment includes a vehicle body 1, on which tires 5 and a chassis assembly 6 are mounted. The electrical assembly 2 and the thermal management system are mounted on the platform assembly 3. The design of the vehicle body 1, tires 5, and chassis assembly 6 of the mobile carrier unit results in a compact size and easy transportation of the entire device. This allows the device to be towed on rural roads or hoisted and disassembled in mountainous areas, overcoming the problem of limited mobility of large charging vehicles and enhancing the device's mobility in complex terrain.

[0084] Furthermore, the platform assembly 3 includes a platform base 30, a bracket 33, and a protective plate 32. The platform base 30 is mounted on the vehicle body 1 of the mobile bearing unit. The bracket 33 is mounted on the platform base 30. The protective plate 32 is mounted on the four sides and top of the bracket 33. The bottom of the protective plate 32 is fixed to the platform base 30. The electrical assembly 2 includes a first electrical component and a second electrical component. The first electrical component is mounted on the bracket 33, and the second electrical component is mounted on the protective plate 32. The thermal management system is mounted on the platform base 30.

[0085] The combined design of the platform base 30, bracket 33 and protective plate 32 enables modular installation of the electrical assembly 2 and thermal management system, simplifies the assembly process, facilitates later maintenance, and the sealing design of the protective plate 32 can prevent water and dust, effectively protecting the electrical assembly 2.

[0086] Platform assembly 3 also includes a hood 31, which is also installed on the vehicle body 1. The hood 31 is fixedly installed on the platform base 30. During installation, the first electrical component of the electrical assembly 2 is fixedly installed on the bracket 33, the thermal management system is installed on the platform base 30, the bracket 33 is then installed on the platform base 30, and then the protective plate 32 is installed on the bracket 33 and the platform base 30. Then the hood 31 is installed on the platform base 30, and finally the platform base 30 is fixed to the chassis assembly 6 to achieve modular hoisting.

[0087] Specifically, the platform base 30 and the chassis assembly 6 can be connected using fasteners such as bolts and nuts, or a fastening assembly or other structure can be provided between the platform base 30 and the chassis assembly 6 to achieve a detachable fixed connection between the mobile load-bearing unit and the platform assembly 3.

[0088] Example 3

[0089] like Figure 1 – Figure 8 As shown, in this embodiment, based on embodiments one and two, the electrical assembly 2 includes:

[0090] DC-DC converter 7 is used to realize the function of converting stable voltage to DC voltage;

[0091] Battery system 9 is connected in communication with DC-DC converter 7 and is used for energy storage, charging and discharging;

[0092] The storage battery 18 is communicatively connected to the DC-DC converter 7 and the battery system 9 via a power switch 14. The power switch 14 is used to control the start and stop of the charging and discharging device, and the storage battery 18 provides power to the charging and discharging device.

[0093] The charging dock assembly 15 is communicatively connected to the battery system 9. The charging dock assembly 15 is used to charge the battery system 9 when it is used in conjunction with an external power supply device.

[0094] The charging gun assembly 16 is communicatively connected to the DC-DC converter 7. The charging gun assembly 16 is used to charge the battery system 9 when it is working with the device to be charged.

[0095] The controller 10 (abbreviated as VECU) is communicatively connected to the DC-DC converter 7, the battery system 9, the storage battery 18, and the thermal management system. The controller 10 is used to control whether the battery system 9 and the thermal management system are working.

[0096] DC converter 8 is connected to battery system 9 and DC-DC converter 7. DC converter 8 charges battery 18 to prevent battery from being depleted.

[0097] The display 11 (abbreviated as IECU) is connected to the controller 10 and receives data such as charging and discharging status and fault information (such as insulation abnormality and over-temperature alarm) sent by the controller 10. It displays the working status of the device and the operation interface in real time.

[0098] The vehicle-side charging communication controller 12 (abbreviated as EVCC) is connected to the charging dock assembly (to receive charging requests and exchange protocols), and is also connected to the controller 10 and the battery system 9. When the charging dock assembly 15 is connected to an external power supply device (such as a charging pile), it converts the communication protocol of the external power supply device into a protocol that the battery system 9 can recognize, so as to achieve matching and interaction of charging parameters (such as voltage and current).

[0099] The charging communication protocol converter 13 (abbreviation: SECC) is connected to the charging gun assembly (to receive discharge requests and provide feedback on device status) and is also connected to the controller 10 and the battery system 9. When the charging gun assembly 16 is connected to the device to be charged (such as a pure electric excavator), it converts the communication protocol of the device to be charged into a protocol that the battery system 9 can recognize, so as to realize dynamic adjustment of discharge parameters and safe interaction.

[0100] By using a DC-DC converter 7, the compatibility problem of different voltage platforms is solved. This charging and discharging device is particularly suitable for pure electric excavators with voltages between 100VDC and 540VDC, meeting the energy replenishment needs of pure electric excavators of different tonnages such as 5-ton (550VDC) and 2-ton (100-300VDC), improving compatibility, being able to carry loads, and also powering other equipment. It is highly adaptable, compact in structure, and easy to transport.

[0101] Furthermore, the electrical assembly also includes an insulation tester 38 and a vehicle wiring harness 17. The insulation tester 38 can detect the insulation status of the positive and negative terminals of the charging gun assembly to the vehicle body 1 or the ground when the charging device discharges externally, playing a safety protection role. The battery system 9 includes a battery pack 19, a battery management system 20 (BMS), a high-voltage box 21, a high-voltage battery wiring harness 22, and a low-voltage battery wiring harness 23; the charging socket assembly 15 includes a high-voltage charging wiring harness 24, a charging socket 25, and a low-voltage charging wiring harness 26; the charging gun assembly 16 includes a charging gun 27, a high-voltage discharge wiring harness 28, and a low-voltage discharge wiring harness 29. The vehicle wiring harness 17 connects the DC-DC converter 7, DC converter 8, VECU, IECU, EVCC, SECC, power switch 14, battery 18, BMS, low-voltage battery wiring harness 23, low-voltage charging wiring harness 26, and low-voltage discharge wiring harness 29. The vehicle wiring harness 17 integrates the electrical connections of various components, simplifying wiring while ensuring stable signal and power transmission.

[0102] The battery pack 19 is connected to the high-voltage box 21 via the high-voltage battery harness 22 to achieve high-power charging and discharging. Both the battery pack 19 and the high-voltage box 21 are connected to the battery management system 20 via the low-voltage battery harness 23 to achieve precise monitoring. The battery management system 20 manages the battery status in real time, which can prevent overcharging, over-discharging and abnormal temperature, improve the safety and service life of the battery system 9, and ensure stable and reliable energy output of the charging and discharging device.

[0103] Example 4

[0104] like Figures 6-8 As shown, based on the above embodiments, the thermal management system of this embodiment includes a water-cooled assembly 4, which includes a water-cooled unit 34, a PTC heater 35, a water pipe 36, and an expansion tank 37. The water-cooled unit 34 and the PTC heater 35 are fixed on the platform base 30. The water-cooled unit 34 is used for cooling and controlling the working state of the water-cooled assembly 4, and the PTC heater 35 is used for heating, which plays the role of heating the coolant.

[0105] The water pipe 36 connects the water-cooled unit 34, the PTC heater 35, the expansion tank 37, and the thermal management circuit within the electrical assembly 2, thus realizing the heat dissipation and heating circuit of the entire device.

[0106] The expansion tank 37 is also equipped with a temperature sensor and a liquid level indicator to facilitate monitoring of the cooling system status and improve the reliability of thermal management. In the thermal management system, the water-cooled unit 34 and the PTC heater respectively realize the cooling and heating functions. Together with the circulation loop connected by the water pipe 36, it can automatically adjust according to the temperature of the battery pack 19 (such as heating at low temperatures and cooling at high temperatures) to ensure that the battery pack 19 works at a suitable temperature and avoids the impact of abnormal temperature on charging and discharging efficiency or the occurrence of safety accidents (such as fires).

[0107] Example 5

[0108] like Figures 9-12 As shown, this embodiment provides a charging control method, which is applied to a charging and discharging device as described in the above embodiment (due to space limitations, the letters in the figure are abbreviations of specific components; DC stands for DC converter 8, DC-DC stands for DC-DC converter 7, and they are not listed individually here; each component corresponds to its letter abbreviation). Specifically, it includes the following steps:

[0109] Acquire the working mode signal of the charging and discharging device, and control the charging and discharging device to enter the working mode corresponding to the working mode signal according to the working mode signal. The working modes include external power replenishment mode and self-power replenishment mode.

[0110] When the charging and discharging device is in external power replenishment mode, after the charging and discharging device is connected to the device to be replenished, the charging and discharging device is controlled to form a discharge circuit with the device to be replenished in order to perform gradient discharge on the device to be replenished.

[0111] When the charging and discharging device is in its own power replenishment mode, after an external power replenishment device is connected to the charging and discharging device, the charging and discharging device is controlled to form a charging circuit with the external power replenishment device in order to perform gradient charging on the charging and discharging device.

[0112] Specifically, controlling the charging / discharging device to form a discharge circuit with the device to be powered, so as to perform gradient discharge on the device to be powered, includes:

[0113] The device to be charged is subjected to gradient discharge based on the actual temperature of the battery pack 19 in the battery system of the charging and discharging device and the preset charging temperature range.

[0114] Preferably, such as Figure 12 As shown, the preset charging temperature range includes multiple temperature intervals, including a first temperature interval, a second temperature interval, ..., an Nth temperature interval, where the temperatures from the first temperature interval to the Nth temperature interval increase in a gradient. The gradient discharge of the device to be charged, based on the actual temperature of the battery pack in the charging and discharging device and the preset charging temperature range, includes:

[0115] When the actual temperature of the battery pack 19 is within the first temperature range, the percentage of charging power of the control charging and discharging device gradually increases from 0% to the first preset value as the temperature of the battery pack rises.

[0116] When the actual temperature of the battery pack 19 is within the second temperature range, the percentage of charging power of the control charging and discharging device is kept at a first preset value as the temperature of the battery pack increases.

[0117] When the actual temperature of the battery pack 19 is within the third temperature range, the percentage of charging power of the control charging and discharging device gradually increases from the first preset value to the second preset value as the temperature of the battery pack rises, and the first preset value is less than the second preset value.

[0118] When the actual temperature of the battery pack 19 is within the fourth temperature range, the percentage of charging power of the control charging and discharging device is kept at the second preset value as the temperature of the battery pack increases.

[0119] And so on.

[0120] Specifically, such as Figure 12 As shown, the preset charging temperature range is -5℃ to 35℃, divided into 8 temperature zones (N=8). The corresponding charging power control for each zone is as follows:

[0121]

[0122] The gradient discharge of the device to be recharged, based on the actual temperature of the battery pack 19 in the charging and discharging device and the preset charging temperature range, includes:

[0123] When the actual temperature of the battery pack 19 is within -5℃ to -0℃, the percentage of charging power of the control charging and discharging device gradually increases from 0% to 30% as the temperature of the battery pack 19 increases;

[0124] When the actual temperature of the battery pack 19 is within 0℃~5℃, the percentage of charging power of the control charging and discharging device is maintained at 30% as the temperature of the battery pack 19 increases;

[0125] When the actual temperature of the battery pack 19 is within 5℃~10℃, the percentage of charging power of the control charging and discharging device increases from 30% to 50% as the temperature of the battery pack 19 increases; when the actual temperature of the battery pack 19 is within 10℃~15℃, the percentage of charging power of the control charging and discharging device remains at 50% as the temperature of the battery pack increases.

[0126] And so on.

[0127] When the actual temperature of the battery pack 19 is between 25°C and 30°C, the charging power increases from 70% to 100%; when the actual temperature of the battery pack 19 is between 30°C and 35°C, the charging power percentage of the charging and discharging device is maintained at 100%.

[0128] In this embodiment, the charging control method for the charging and discharging device during the discharging or charging process further includes:

[0129] Detect the actual temperature of battery pack 19;

[0130] When the actual temperature of the battery pack 19 is within the preset charging temperature range, charging or discharging will continue.

[0131] When the actual temperature of the battery pack 19 is lower than the first threshold, the thermal management system is controlled to heat the battery pack 19 and at the same time, it is detected whether the actual temperature of the battery pack 19 rises. If the temperature of the battery pack 19 rises, the thermal management system is controlled to continue heating the battery pack 19. If the actual temperature of the battery pack 19 does not rise, the display 11 is controlled to alarm and stop charging or discharging. The first threshold is lower than or equal to the lowest value of the preset charging range.

[0132] When the actual temperature of the battery pack 19 is greater than the second threshold, the thermal management system is controlled to cool the battery pack 19 and at the same time, it is detected whether the actual temperature of the battery pack 19 has decreased. If the actual temperature of the battery pack 19 has decreased, the thermal management system is controlled to continue cooling the battery pack 19 and the charging and discharging device reduces the charging and discharging power. If the actual temperature of the battery pack 19 has not decreased, the display 11 is controlled to alarm and stop charging or discharging. The second threshold is higher than or equal to the highest value of the preset charging range.

[0133] Specifically, the first threshold is -5℃. When the actual temperature of the battery pack 19 is lower than -5℃, such as -10℃, the thermal management system is controlled to heat the battery pack 19. At the same time, the actual temperature of the battery pack 19 is detected to see if it rises. If the temperature of the battery pack rises, the thermal management system is controlled to continue heating the battery pack 19. If the actual temperature of the battery pack 19 does not rise, the display is controlled to alarm and charging or discharging is stopped.

[0134] Specifically, the second threshold is 35°C. When the actual temperature of the battery pack 19 is greater than 35°C, such as 40°C, the thermal management system is controlled to cool the battery pack 19. At the same time, the actual temperature of the battery pack 19 is detected to see if it decreases. If the actual temperature of the battery pack 19 decreases, the thermal management system is controlled to continue cooling the battery pack 19 and the charging and discharging device is controlled to reduce the charging and discharging power. If the actual temperature of the battery pack 19 does not decrease, the display 11 is controlled to alarm and stop charging or discharging.

[0135] In this embodiment, the charging control method for the charging and discharging device during the discharging or charging process further includes:

[0136] The SOC value of the battery pack 19 and the SOC value of the device to be recharged are detected;

[0137] When the SOC value of battery pack 19 is greater than or equal to the preset power value and the SOC value of the device to be charged is not fully charged, charging continues; otherwise, charging stops.

[0138] Specifically, the preset charge level is 20%. During the charging and discharging process, the controller 10 continuously monitors the temperature of the device itself and the device to be charged. When the temperature is within a reasonable range, charging continues. At this time, the controller 10 detects the SOC value of the battery pack 19 sent from the battery management system 20 and detects the SOC value of the device to be charged. If the SOC value of the battery pack 19 is ≥20% and the SOC value of the device to be charged is <100%, charging continues; otherwise, charging stops to prevent overcharging of the charging device and over-discharging of the charging and discharging device.

[0139] When the temperature is too high during charging and discharging, the controller controls the water-cooled unit 34 to work. At the same time, the controller detects the temperature change. If the temperature changes in the normal direction, the water-cooled unit 34 will continue to work while charging and discharging at a reduced power until the controller detects that the temperature is normal. Then, the controller controls the water-cooled unit 34 to stop working and the device continues to charge and discharge at the rated power.

[0140] If the temperature remains abnormal, the display 11 will issue an alarm, and the controller 10 will simultaneously control the battery management system 20 and the DC-DC converter 7 to reduce the high voltage, ending the charging and discharging process. Charging will stop when either of these high-voltage reduction operations is triggered to prevent fires caused by abnormal high temperatures and to avoid safety accidents due to temperature abnormalities.

[0141] Furthermore, during charging or discharging, the controller constantly monitors the status of the casing. If the casing is opened, the charging device will apply high voltage to prevent electric shock and ensure the safety of the charging device.

[0142] In this embodiment, before the charging / discharging device begins discharging or charging, the charging control method further includes:

[0143] The insulation resistance between the positive and negative terminals of the charging gun assembly of the charging and discharging device and the ground is detected by an insulation tester for the charging and discharging device.

[0144] Determine whether the insulation resistance value meets the preset safety threshold. The preset safety threshold refers to the insulation resistance threshold between the positive and negative poles of the charging and discharging circuit and the ground (mobile carrier vehicle body). It is determined to be safe when the insulation resistance is ≥20MΩ by the insulation tester 38, and the contactor is allowed to close to form a charging and discharging circuit.

[0145] If the insulation resistance value meets the preset safety threshold (20MΩ), the contactor in the high voltage box of the battery system and the contactor in the DC-DC converter will close during discharge or during charging to form a discharge circuit or a charging circuit.

[0146] If the insulation resistance value does not meet the preset safety threshold (20MΩ), the control display will alarm and show fault information.

[0147] Specifically, the charging control method includes the following steps:

[0148] Obtain the signal of the power switch 14;

[0149] When the signal of the power switch 14 is an off signal, control the charge and discharge device to enter the sleep mode;

[0150] When the signal of the power switch 14 is an on signal, control the charge and discharge device to perform self-check. When the self-check of the charge and discharge device is normal, execute obtaining the working mode signal of the charge and discharge device;

[0151] Controlling the self-check of the charge and discharge device includes: the self-check process of the DC converter 8 and the self-check process of the battery power;

[0152] When the self-check result of the DC converter 8 is abnormal, control the display 11 to alarm and display the fault information;

[0153] When the self-check result of the DC converter 8 is normal, then perform the self-check of the battery 18 power;

[0154] Among them, the self-check process of the battery 18 power includes:

[0155] Detect the power of the battery 18;

[0156] When the detected power value is greater than or equal to the preset power threshold (M%) of the total power, the controller controls the main contactor of the DC-DC converter 7 to close and the auxiliary contactor to open, and all the electric energy of the charge and discharge device is discharged externally. At this time, the external efficiency of the charge and discharge device is the highest;

[0157] When the detected power value is less than M% (20 < M < 100) of the total power, the controller controls the main contactor of the DC-DC converter 7 to close and the auxiliary contactor to close. A first preset proportion of the electric energy of the charge and discharge device is discharged externally, and a second preset proportion of the electric energy of the charge and discharge device is used to supplement the power of the battery 18 through the DC converter 8 until the power of the battery is greater than or equal to M% (20 < M < 100) of the total power. At the same time, continue to perform the power detection of the battery 18. This realizes ensuring that the battery always works in the best state, extending the life of the battery while also improving the utilization rate of electric energy.

[0158] Among them, the main contactor of the DC-DC converter 7 controls the on and off of the external discharge circuit, and the auxiliary contactor of the DC-DC converter 7 controls the on and off of the input end of the DC converter 8.

[0159] Further, when the power switch 14 is closed, the device does not discharge externally. At this time, the controller is in a periodic sleep state and works once every N days (where 7 < N < 30). When the controller works, it will detect the power level of the battery. When the power value is greater than or equal to M% (20 < M < 100) of the total power, it ends until the next detection cycle.

[0160] When the detected power value is less than M% of the total power, the controller processes the self-check result of the DC converter 8. When the self-check result is abnormal, the display 11 alarms and displays the fault information; when the self-check is normal, the controller controls the closing of the secondary contactor of the DC-DC converter 7, and part of the electrical energy of the device passes through the DC converter 8 to charge the battery 18 until the battery power value is greater than or equal to M% (20 < M < 100) of the total power and ends until the next detection cycle.

[0161] Further, the external charging mode includes a loaded mode, a first discharge mode, and a second discharge mode. The first discharge mode charges electric construction machinery such as electric excavators, and the second discharge mode charges other devices.

[0162] The loaded mode means that when the electric excavator is short of power, the charging and discharging device directly acts as an external power source of the electric excavator to drive the electric excavator to work. Before working, it will detect the temperature of its own battery pack 19. When the temperature of the battery pack 19 is below -5°C, such as in the range of -10°C to -5°C, the charging and discharging device controls the thermal management system to work to heat the battery pack 19. When the controller 10 detects that the temperature of the battery pack 19 is above -5°C, it outputs power in a gradient until the power requested by the electric excavator is met.

[0163] The discharge mode for other devices means a low-power mode that provides electrical energy to other electrical devices. If the load is low, this mode can be directly used. If the load is high, the device will automatically switch to the loaded mode. When the temperature of the battery pack is below -5°C, the device first heats the battery pack.

[0164] Further, controlling the self-check of the charging and discharging device also includes the self-check process of the thermal management system and the self-check process of the battery system. Before the charging and discharging device is started, a comprehensive self-check needs to be performed to ensure that the functions of each component are normal. The self-check content includes the self-check of the DC converter, the self-check of the battery power, the self-check of the thermal management system, and the self-check of the battery management system. The specific process is as follows:

[0165] Self-check process:

[0166] Detection objects: DC-DC converter 7 (the core component for voltage conversion) and DC converter 8 (the component for low-voltage power conversion).

[0167] Detection content:

[0168] DC-DC converter 7: Input / output voltage sampling circuit, IGBT drive module, internal temperature sensor (detection range -40℃~125℃, accuracy ±1℃).

[0169] DC Converter 8: Output voltage stability (26±0.5VDC) and output current (maximum 40A, corresponding to power 500W) when input voltage is 300-800VDC.

[0170] Result processing: If the self-test is abnormal (such as a DC-DC converter temperature sensor failure), the display 11 will show "DC module failure" (red text + buzzer alarm), and the working mode will be prohibited.

[0171] Battery power self-test process:

[0172] Test subject: Battery 18.

[0173] Test parameters: Battery capacity 18% (indirectly determined by voltage).

[0174] Thermal management system self-test process:

[0175] Items to be tested: water-cooled unit 34, PTC heater 35, water pipe 36, and expansion tank 37.

[0176] Test content:

[0177] Water-cooled unit 34: Compressor start / stop response, fan speed, refrigerant pressure;

[0178] PTC heater 35: heating power, surface temperature;

[0179] Expansion tank 37: Liquid level and temperature sensor (NTC, accuracy ±1℃).

[0180] Result handling: If the liquid level is <20% or the PTC heater has no power output, the display will show "thermal management fault" and charging and discharging will be prohibited.

[0181] Battery Management System (BMS) Self-Test Process

[0182] Test objects: Battery pack 19, Battery management system 20, High voltage box 21.

[0183] BMS self-test includes: individual cell voltage sampling, temperature sampling, and SOC calculation accuracy.

[0184] High-voltage box self-test items: contactor engagement / disengagement response time (≤50ms), insulation resistance (≥200MΩ in the off state).

[0185] Result handling: If the voltage deviation of a single cell is >50mV or the contactor is stuck, the display will show "Battery system fault" and the high voltage will be reduced (all contactors will be disconnected).

[0186] Furthermore, the charging control method also includes:

[0187] When the charging and discharging device is in sleep mode, control the charging and discharging device to work periodically once;

[0188] When the charging and discharging device is working, it detects the charge value of the battery 18 and determines whether the charge value is equal to the preset charge threshold.

[0189] When the charge value of battery 18 is greater than or equal to the preset charge threshold, the charging and discharging device will stop working until the next cycle.

[0190] When the charge level of battery 18 is less than the preset charge threshold, the DC converter 8 will perform a self-test.

[0191] When the self-test result of DC converter 8 is abnormal, the control display 11 will alarm and display fault information;

[0192] When the self-test result of DC converter 8 is normal, the auxiliary contactor of DC-DC converter 7 is closed, and the battery is charged through DC converter 8 until the battery power value is greater than or equal to the preset power threshold.

[0193] For example, the cycle setting is: wake up once every 15 days (which can be adjusted through controller parameters, ranging from 7 to 30 days), and the wake-up time lasts for 5 minutes (to complete power detection and recharging).

[0194] For example, if M is 80, and the battery charge is ≥80%, no recharging is required and the controller immediately enters sleep mode; if the battery charge is <80%, the DC converter 8 performs a self-test.

[0195] Furthermore, the operating modes also include standby mode, and the charging control methods also include:

[0196] When the charging and discharging device is in the standby mode, after the charging and discharging device completes its self-test and waits for a preset time, if the charging and discharging device does not receive an instruction, it will enter the sleep mode.

[0197] The standby mode is when the entire charging and discharging device completes its self-test and waits for time t1. If the waiting time t1 > t (set time t = 5 min), the charging and discharging device will enter sleep mode to save power while waiting for the next operation.

[0198] Example 6

[0199] like Figures 1-11As shown, this embodiment provides the specific installation structure and working process of the charging and discharging device. When assembling the charging and discharging device, the three most critical and heaviest electrical components—the DC-DC converter 7, the battery pack 19, and the high-voltage box 21—are first fixed on the bracket 33. Then, the bracket 33 is hoisted onto the platform base 30. After fixing the thermal management system onto the platform base 30, the platform base 30 is hoisted onto the chassis assembly 6 of the vehicle body 1. Then, the DC converter 8, controller 10, display 11, and vehicle-side charging communication controller are installed. 12. Charging communication protocol converter; 13. Power switch; 14. Charging base assembly; 15. Charging gun assembly; 16. Car wiring harness; 17. Battery; 18. Insulation tester; 38. Battery management system; 20. Battery high voltage wiring harness; 22. Battery low voltage wiring harness; 23. Installation of charging base assembly 15 and charging gun assembly 16 (the cover 31 has an opening for the charging gun to be exposed through the opening, and the charging gun of the charging pile is inserted into the charging base through the opening), then install the protective plate 32, and finally install the cover 31. The entire modular installation process is completed.

[0200] The protective plate 32 includes a front baffle 39, a rear baffle 40, side baffles 41, and an upper baffle 42. The protective plate 32 has two main functions: First, it secures the DC converter 8, controller 10, display 11, vehicle-side charging communication controller 12, charging communication protocol converter 13, power switch 14, charging socket assembly 15, charging gun assembly 16, and battery management system 20. The controller 10, display 11, vehicle-side charging communication controller 12, charging communication protocol converter 13, power switch 14, charging socket assembly 15, and charging gun assembly 16 are fixed to the front baffle 39, while the DC converter 8 and battery management system 20 are fixed to the rear baffle 40. The baffles are connected by bolts, and sealing strips are installed on the connecting surfaces. The front baffle 39 and rear baffle 40 have round holes with sealing sleeves for routing wiring harnesses and water pipes 36. Second, it provides a sealed protection for the electrical assembly 2. The protective plate 32 features a sealed design, making it waterproof and dustproof. The bottom of the protective plate 32 is fixed to the platform base 30 using fasteners such as bolts and nuts. The front baffle 39, rear baffle 40, side baffle 41, and upper baffle 42 are all mounted on the bracket 33. The heat exchange and liquid storage components of the thermal management system, such as the water-cooled unit 34, PTC heater 35, and expansion tank 37, are all located on the outside of the protective plate 32 to facilitate heat exchange with the air and eliminate the need for a sealed design. The battery pack 19 is regulated by connecting to the thermal management circuit in the electrical assembly 2 via water pipe 36.

[0201] When the pure electric excavator needs recharging while waiting for the charging equipment, the power switch 14 is switched from the OFF position to the ON position. First, the charging device enters a self-test process. After the DC converter 8, battery 18, DC-DC converter 7, battery management system 20, and thermal management system complete their self-tests, they communicate with the controller 10. The controller 10 sends the processing information to the display 11, which indicates that the status is normal and displays the "Start Charging" option. The operator inserts the charging gun 27 into the charging port of the pure electric excavator or other construction machinery that needs charging and clicks the "Start Charging" option on the display 11. At this time, the equipment being charged communicates with the charging communication protocol converter 13 of the charging and discharging device. The charging communication protocol converter 13 sends the charging request to the controller 10. At this time, the insulation detector 38 starts working, detecting the insulation resistance between the positive and negative terminals of the discharge high-voltage harness 28 and the ground, and sends the results to the controller 10 for processing. After passing the insulation test, the controller 10 communicates with the battery management system 20... The DC-DC converter 7 communicates with the battery management system 20, which controls the contactor in the high-voltage box 21 to close. The battery pack 19 forms a path with the input port of the high-voltage box 21 through the battery high-voltage harness 22. The output port of the high-voltage box 21 is connected to the high-voltage input port of the DC-DC converter 7 through the battery high-voltage harness 22. After receiving the request from the controller 10, the DC-DC converter 7 controls the contactor inside it to close. The high-voltage output port of the DC-DC converter 7 is connected to the discharge high-voltage harness 28, and a path is formed by connecting the charging gun 27 to the high-voltage line of the device to be charged, thus starting to charge the pure electric excavator. The display 11 will show the discharge status in real time.

[0202] Among them, the insulation detector 38 detects the insulation value between the positive and negative high voltage output of the charging gun 27 and the ground. When the insulation value is greater than or equal to the allowable safety value of 20 megohms, the controller 10 will issue a discharge request to complete the charging request. When the insulation value does not meet the condition of being greater than or equal to the allowable safety value of 20 megohms, the charging request will not pass, and the display 11 will alarm the fault information, which constitutes the basic safety guarantee of the device.

[0203] When the charging and discharging device needs to be recharged, switch the power switch 14 from the OFF position to the ON position, and insert the charging gun of the external charging device (such as a charging pile) into the charging socket of the charging socket assembly 15. At this time, the external charging device establishes communication with the vehicle-side charging communication controller 12 through the charging low-voltage harness 26. The vehicle-side charging communication controller 12 sends the information to the controller 10 through the vehicle harness 17. After receiving the charging request, the controller 10 sends a request to the battery management system 20. The battery management system 20 controls the contactor in the high-voltage box 21 to close through the battery low-voltage harness 23. At this time, the battery pack 19 forms a path with the input port of the high-voltage box 21 through the battery high-voltage harness 22. The charging high-voltage harness 24 connects the DC charging port of the high-voltage box 21 to the charging socket assembly 15 to form a charging circuit. During the recharge process, the battery management system 20 in the battery system 9 constantly monitors the temperature in the battery pack 19. When the temperature is too high (35°C and above) or too low (-5°C and below), the battery management system 20 communicates with the thermal management system. The thermal management system issues a cooling or heating command according to the request of the battery management system 20. If it is a heating command, the PTC heater 35 will work. When the temperature of the battery pack reaches the first set temperature (e.g., 0°C), the PTC heater 35 reduces its power to heat until the temperature of the battery pack reaches the second set temperature (e.g., 25°C), at which point the PTC heater 35 stops heating. If it is a cooling command, the water-cooled unit 34 will work until the temperature reaches the second set temperature (e.g., 25°C), at which point the thermal management system stops working.

[0204] During the external discharge process, the battery management system 20 in the battery system 9 detects the temperature in the battery pack 19 and the DC-DC converter 7 detects its own internal temperature. When the temperature is too high (35°C and above) or too low (-5°C and below), the battery management system 20 communicates with the water-cooled unit 34. The water-cooled unit 34 will issue a cooling or heating command according to the request of the battery management system 20. If it is a heating command, the PTC heater 35 will work; if it is a cooling command, the water-cooled unit 34 will work.

[0205] Furthermore, if the temperature is too high or too low during charging, the display 11 will issue an alarm and stop charging.

[0206] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0207] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. The implementation schemes in the above embodiments can also be further combined or replaced. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A charging and discharging control method, characterized in that, The charging and discharging control method is applied to a charging and discharging device; the charging and discharging device includes a mobile support unit, on which a platform assembly (3) is detachably mounted, and on which an electrical assembly (2) and a thermal management system are provided; The electrical assembly (2) is used for energy storage, energy input / output conversion and energy monitoring; The thermal management system is connected to the electrical assembly (2) and is used to monitor and control the temperature of the electrical assembly (2); The platform assembly (3) includes a platform base (30), which is mounted on the mobile bearing unit. A bracket (33) is mounted on the platform base (30), and a protective plate (32) is mounted on the bracket (33) around its perimeter and top. The bottom of the protective plate (32) is fixed to the platform base (30). The electrical assembly (2) includes a first electrical component and a second electrical component. The first electrical component is mounted on the bracket (33), the second electrical component is mounted on the guard plate (32), and the thermal management system is mounted on the platform base (30). The charging and discharging control method includes: Acquire the working mode signal of the charging and discharging device, and control the charging and discharging device to enter the working mode corresponding to the working mode signal according to the working mode signal. The working mode includes external power replenishment mode and self-power replenishment mode. When the charging and discharging device is in the external power replenishment mode, after the charging and discharging device is connected to the device to be replenished, the charging and discharging device is controlled to form a discharge circuit with the device to be replenished, so as to perform gradient discharge on the device to be replenished. When the charging and discharging device is in the self-charging mode, after an external charging device is connected to the charging and discharging device, the charging and discharging device is controlled to form a charging circuit with the external charging device to perform gradient charging on the charging and discharging device.

2. The charging and discharging control method according to claim 1, characterized in that, The electrical assembly (2) includes: DC-DC converter (7) is used to realize the function of converting stable voltage to DC voltage; The battery system (9) is communicatively connected to the DC-DC converter (7) and is used for energy storage, charging, and discharging. The storage battery (18) is connected to the DC-DC converter (7) and the battery system (9) via a power switch (14). The power switch (14) is used to control the start and stop of the charging and discharging device. The storage battery (18) provides power to the charging and discharging device. The charging dock assembly (15) is communicatively connected to the battery system (9), and the charging dock assembly (15) is used to charge the battery system (9) when in conjunction with an external power supply device; The charging gun assembly (16) is communicatively connected to the DC-DC converter (7). The charging gun assembly (16) is used by the battery system (9) to charge the device to be charged when it is used in conjunction with the device to be charged. The controller (10) is communicatively connected to the DC-DC converter (7), the battery system (9), the storage battery (18), and the thermal management system. The controller (10) is used to control the battery system (9) and to control whether the thermal management system is working. The first electrical component includes the DC-DC converter (7), the battery pack (19) of the battery system (9) and the high voltage box (21), and the second electrical component includes the controller (10), the charging dock assembly (15) and the charging gun assembly (16).

3. The charging and discharging control method according to claim 1, characterized in that, Controlling the charging / discharging device to form a discharge circuit with the device to be recharged, so as to perform gradient discharge on the device to be recharged, includes: The device to be recharged is subjected to gradient discharge based on the actual temperature of the battery pack in the battery system of the charging and discharging device and the preset charging temperature range.

4. The charging and discharging control method according to claim 3, characterized in that, The preset charging temperature range includes multiple temperature intervals, including a first temperature interval, a second temperature interval, ..., an Nth temperature interval, wherein the temperature from the first temperature interval to the Nth temperature interval increases in a gradient. The gradient discharge of the device to be recharged based on the actual temperature of the battery pack (19) of the battery system (9) in the charging and discharging device and the preset charging temperature range includes: When the actual temperature of the battery pack (19) is within the first temperature range, the percentage of the charging power of the charging and discharging device is controlled to gradually increase from 0% to a first preset value as the temperature of the battery pack increases. When the actual temperature of the battery pack (19) is within the second temperature range, the charging power percentage of the charging and discharging device is controlled to remain at the first preset value as the temperature of the battery pack (19) increases; When the actual temperature of the battery pack (19) is within the third temperature range, the percentage of charging power of the charging and discharging device is controlled to gradually increase from the first preset value to the second preset value as the temperature of the battery pack (19) increases, and the first preset value is less than the second preset value. When the actual temperature of the battery pack (19) is within the fourth temperature range, the charging power percentage of the charging and discharging device is controlled to remain at the second preset value as the temperature of the battery pack (19) increases; And so on.

5. The charging and discharging control method according to claim 3, characterized in that, During the discharge or charging process of the charging and discharging device, the charging and discharging control method further includes: Detect the actual temperature of the battery pack (19); When the actual temperature of the battery pack (19) is within the preset charging temperature range, charging or discharging continues; When the actual temperature of the battery pack (19) is lower than the first threshold, the thermal management system is controlled to heat the battery pack (19) and at the same time, it is detected whether the actual temperature of the battery pack (19) rises. If the temperature of the battery pack (19) rises, the thermal management system is controlled to continue heating the battery pack (19). If the actual temperature of the battery pack (19) does not rise, the display (11) is controlled to alarm and stop charging or discharging. The first threshold is lower than or equal to the lowest value of the preset charging temperature range. When the actual temperature of the battery pack (19) is greater than the second threshold, the thermal management system is controlled to cool the battery pack (19) and at the same time, it is detected whether the actual temperature of the battery pack (19) has decreased. If the actual temperature of the battery pack (19) decreases, the thermal management system is controlled to continue cooling the battery pack (19) and the charging and discharging device reduces the charging and discharging power. If the actual temperature of the battery pack (19) does not decrease, the display (11) is controlled to alarm and stop charging or discharging. The second threshold is higher than or equal to the highest value of the preset charging temperature range.

6. The charging and discharging control method according to claim 3, characterized in that, During the discharge or charging process of the charging and discharging device, the charging and discharging control method further includes: Detect the SOC value of the battery pack (19) and the SOC value of the device to be recharged; When the SOC value of the battery pack (19) is greater than or equal to the preset power value and the SOC value of the device to be recharged is not fully charged, charging continues; otherwise, charging stops.

7. The charging and discharging control method according to claim 1, characterized in that, Before the charging / discharging device begins discharging or charging, the charging / discharging control method further includes: The insulation resistance values ​​between the positive and negative terminals of the charging gun assembly of the charging and discharging device and the ground are detected by the insulation tester of the charging and discharging device. Determine whether the insulation resistance value meets the preset safety threshold; If the insulation resistance value meets the preset safety threshold, the contactor in the high voltage box (21) of the battery system (9) and the contactor in the DC-DC converter (7) are closed during discharge or during charging, so as to form a discharge circuit or a charging circuit. If the insulation resistance value does not meet the preset safety threshold, the control display (11) will alarm and display fault information.

8. The charging and discharging control method according to claim 2, characterized in that, The charging and discharging control method further includes the following steps: Obtain the signal from the power switch (14); When the power switch (14) sends a closed signal, the charging and discharging device is controlled to enter a sleep mode; When the power switch (14) is in the open position, the charging and discharging device is controlled to perform a self-test. If the self-test of the charging and discharging device is normal, the device is used to obtain the working mode signal of the charging and discharging device. The self-test of the charging and discharging device includes: the self-test process of the DC converter (8) and the self-test process of the battery (18) power level; When the self-test result of the DC converter (8) is abnormal, the control display (11) alarms and displays fault information; When the self-test result of the DC converter (8) is normal, the self-test of the battery (18) power is performed. The self-check process of the battery (18) power level includes: Detect the charge level of the storage battery (18); When the charge of the battery (18) is greater than or equal to the preset charge threshold, the main contactor of the DC-DC converter (7) is closed and the auxiliary contactor is opened, and all the electrical energy of the charging and discharging device is discharged to the outside. When the charge of the battery (18) is less than the preset charge threshold, the main contactor and the auxiliary contactor of the DC-DC converter (7) are closed. The first preset proportion of the electrical energy of the charging and discharging device is discharged to the outside, and the second preset proportion of the electrical energy is replenished to the battery (18) through the DC converter (8) until the charge of the battery (18) is greater than or equal to the preset charge threshold.

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