Charging control method, charging circuit and electric device

Abstract

The invention discloses a charging control method, a charging circuit and an electric device, and relates to the technical field of batteries. The electric device comprises a battery module and a charging circuit connected with the battery module; the battery module is provided with a plurality of battery packs which are connected in series and in parallel; the method comprises the steps that after connection is established between a charging input interface and an external power supply, the power supply type and the output voltage of the external power supply are determined; under the condition that the power supply type of the external power supply is a direct-current power supply and the output voltage of the external power supply is not matched with the charging voltage of the battery module to be charged, controlling the series-parallel connection relationship among the plurality of battery packs to be switched, so that the plurality of battery packs of the battery module form a plurality of charging groups, the charging voltage of each charging group is matched with the output voltage of an external power supply; therefore, the output voltage accessed to the external power supply charges each charging group, supplies voltage to the load and outputs the voltage to the energy storage output interface. The invention aims to improve the working flexibility of the electric device.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a charging control method, a charging circuit and an electric device. Background Art

[0002] With the development of electric vehicles, the DC bus of vehicles has gradually increased from 400V to 800V. For a long time, charging speed and endurance have been the shortcomings of electric vehicles. When the high-voltage architecture of electric vehicles is increased from 400V to 800V, the charging current will be halved (P=U*I) at the same charging power, which can reduce the loss and heat generation during charging (P=I2*R), and can also reduce the cable radius, achieving the effect of reducing costs and weight.

[0003] However, the existing DC charging pile still outputs 400V DC. Therefore, in the prior art, a corresponding switch circuit is set in the battery module to change the series-parallel relationship of multiple battery packs in the battery module, thereby matching the charging voltage of the battery module with the output voltage of the DC charging pile. However, this adaptive matching method will result in the DC charging pile being unable to power the load of the electric vehicle. Summary of the invention

[0004] The main purpose of the present invention is to provide a charging control method, a charging circuit and an electric device, aiming to improve the working flexibility of the electric device.

[0005] To achieve the above object, the present invention proposes a charging control method, which is applied to an electric device, wherein the electric device includes a battery module and a charging circuit connected to the battery module, wherein the charging circuit has a charging input interface for connecting to an external power source and an energy storage output interface for outputting electric energy to a load of the electric device; the battery module has a plurality of battery packs connected in series and parallel to each other;

[0006] The charging control method comprises:

[0007] After establishing a connection between the charging input interface and the external power source, determining the power source type of the external power source and the output voltage of the external power source based on the charging handshake information between the charging input interface and the external power source;

[0008] When the power type of the external power supply is a DC power supply and the output voltage of the external power supply matches the charging voltage of the battery module to be charged, the output voltage of the connected external power supply is directly used to charge the battery module and output to the energy storage output interface to supply power to the load;

[0009] When the power type of the external power source is a DC power source and the output voltage of the external power source does not match the charging voltage of the battery module to be charged, the series-parallel connection relationship between the multiple battery packs is controlled to switch so that the multiple battery packs of the battery module form multiple charging groups, and the charging voltage of each charging group matches the output voltage of the external power source;

[0010] When the charging voltage of the charging group matches the output voltage of the external power supply, the output voltage of the external power supply is connected to charge each charging group, and the output voltage of the external power supply is converted into a load power supply voltage and output to the energy storage output interface to power the load.

[0011] In one embodiment, when the output voltage of the external power source does not match the charging voltage of the battery module to be charged, the method of controlling the series-parallel connection relationship between the multiple battery packs to switch so that the multiple battery packs of the battery module form multiple charging groups, and the charging voltage of each charging group matches the output voltage of the external power source specifically includes:

[0012] When the output voltage of the external power source is greater than the charging voltage of the battery module to be charged, the plurality of battery packs are controlled to switch to a first connection state; in the first connection state, the plurality of battery packs form a charging group connected in series;

[0013] When the output voltage of the external power source is lower than the charging voltage of the battery module to be charged, the plurality of battery packs are controlled to be in a second connection state; in the second connection state, the plurality of battery packs form a plurality of charging groups connected in parallel.

[0014] In one embodiment, the charging input interface has a DC charging positive terminal and a DC charging negative terminal, the charging circuit includes a first switch circuit, the first switch circuit includes a first switch, a second switch and a third switch; the first switch is connected in series between the two interconnected battery packs; the positive electrode of each battery pack is connected to the positive electrode of the DC charging terminal through the second switch, and the negative electrode of each battery pack is connected to the negative electrode of the DC charging terminal through the third switch;

[0015] The method of controlling the plurality of battery packs to switch to a first connection state when the output voltage of the external power supply is greater than the charging voltage of the battery module to be charged; in the first connection state, the plurality of battery packs form a charging group connected in series; and controlling the plurality of battery packs to switch to a second connection state when the output voltage of the external power supply is less than the charging voltage of the battery module to be charged; in the second connection state, the plurality of battery packs form a plurality of charging groups connected in parallel specifically includes:

[0016] When the output voltage of the external power supply is greater than the charging voltage of the battery module to be charged, the first switch is controlled to be turned on, and the second switch and the third switch are controlled to be turned off, so as to control the multiple battery packs to switch to the first connection state;

[0017] When the output voltage of the external power source is lower than the charging voltage of the battery module to be charged, the second switch and the third switch are controlled to be turned on, and the first switch is controlled to be turned off, so as to control the multiple battery packs to switch to the second connection state.

[0018] In one embodiment, the charging circuit further includes a bus switch circuit; the bus switch circuit is connected in series between the battery module and the energy storage output interface;

[0019] Before controlling the series-parallel connection relationship between the plurality of battery packs to switch, the method further includes:

[0020] When the power type of the external power supply is a DC power supply and the output voltage of the external power supply does not match the charging voltage of the battery module to be charged, the load connected to the energy storage output interface is stopped, and the bus switch circuit is controlled to disconnect the path between the battery module and the energy storage output interface.

[0021] In one embodiment, the charging input interface includes a DC input terminal for connecting to a DC charging voltage and an AC charging terminal for connecting to an AC charging voltage;

[0022] After the step of determining the power type of the external power source and the output voltage of the external power source based on the charging handshake information between the external power source and the external power source, the method further includes:

[0023] When the power type of the external power source is an AC power source, the output voltage of the connected external power source is converted into a charging voltage of the corresponding battery module and a load power supply voltage of the load to charge the battery module and supply power to the load.

[0024] In one embodiment, the charging circuit further includes a voltage conversion circuit for voltage conversion and a detection circuit for detecting the input terminal voltage of the voltage conversion circuit;

[0025] Before the step of converting the output voltage of the connected external power supply into a load power supply voltage and outputting the voltage to the energy storage output interface, the method further includes:

[0026] Acquiring detection information of an input terminal of a voltage conversion circuit;

[0027] In the case where the detection information does not match the output voltage of the external power supply, a fault signal is output.

[0028] The present invention further provides a charging circuit, which is applied to an electric device, wherein the electric device includes a battery module, wherein the battery module has a plurality of battery packs connected in series and parallel to each other; the charging circuit includes: a charging input interface, an energy storage output interface, a first switch circuit, a voltage conversion circuit and a control circuit;

[0029] The charging input interface is used to access the output voltage of an external power source;

[0030] The energy storage output interface is used to output electric energy to the electric device load;

[0031] A control circuit, configured to determine the power type of the external power source and the output voltage of the external power source based on charging handshake information between the charging input interface and the external power source after establishing a connection between the charging input interface and the external power source;

[0032] When the power type of the external power supply is a DC power supply and the output voltage of the external power supply matches the charging voltage of the battery module to be charged, the output voltage of the connected external power supply is directly used to charge the battery module and output to the energy storage output interface to supply power to the load;

[0033] When the power type of the external power source is a DC power source and the output voltage of the external power source does not match the charging voltage of the battery module to be charged, the first switch circuit is controlled to switch the series-parallel connection relationship between the multiple battery packs, so that the multiple battery packs of the battery module form multiple charging groups, and the charging voltage of each charging group matches the output voltage of the external power source;

[0034] When the charging voltage of the charging group matches the output voltage of the external power supply, the output voltage of the external power supply is connected to charge each charging group, and the voltage conversion circuit is controlled to convert the output voltage of the connected external power supply into a load power supply voltage and output it to the energy storage output interface to power the load.

[0035] In one embodiment, the charging input interface has a DC charging positive terminal and a DC charging negative terminal; the first switch circuit further includes a first switch, a second switch and a third switch; the first switch is connected in series between the two interconnected battery packs; the positive electrode of each battery pack is connected to the DC charging positive terminal through the second switch, and the negative electrode of each battery pack is connected to the DC charging negative terminal through the third switch;

[0036] The control circuit is further used to control the first switch to be turned on and the second switch and the third switch to be turned off when the output voltage of the external power supply is greater than the charging voltage of the battery module to be charged; and to control the second switch and the third switch to be turned on and the first switch to be turned off when the output voltage of the external power supply is less than the charging voltage of the battery module to be charged.

[0037] In one embodiment, the charging input interface includes a DC charging terminal for connecting to a DC charging voltage and an AC charging terminal for connecting to an AC charging voltage; the voltage conversion circuit also includes a DC conversion switch circuit, a first end of the DC conversion switch circuit is electrically connected to the DC charging terminal, a controlled end of the DC conversion switch circuit is electrically connected to the control circuit, and a second end of the DC conversion switch circuit is electrically connected to the AC charging terminal;

[0038] Wherein, the control circuit is also used to control the conduction state of the DC conversion switch circuit, so that the DC charging voltage is converted into a load power supply voltage and output to the energy storage output interface to supply power to the load.

[0039] In one embodiment, the charging circuit also includes a bus switch circuit, a first end of the bus switch circuit is electrically connected to the battery module, a controlled end of the bus switch circuit is electrically connected to the control circuit, and a second end of the bus switch circuit is electrically connected to the energy storage output interface; the bus switch circuit is used to turn on or off the path between the battery module and the energy storage output interface according to a corresponding bus switch control signal output by the control circuit.

[0040] In one embodiment, the charging circuit further includes a detection circuit, an input end of the detection circuit is electrically connected to an input end of the voltage conversion circuit, and an output end of the detection circuit is electrically connected to the control circuit;

[0041] The control circuit is further used to control the detection circuit to obtain detection information of the input end of the voltage conversion circuit; and output a fault signal when the detection information does not match the output voltage of the external power supply.

[0042] The present invention further provides an electric device, comprising a battery module and any one of the charging circuits described above.

[0043] The technical solution of the present invention determines the power type of the external power supply and the output voltage of the external power supply through the charging handshake information between the external power supply and the external power supply after establishing a connection between the charging input interface and the external power supply. When the power type of the external power supply is a DC power supply and the output voltage of the external power supply matches the charging voltage of the battery module to be charged, the output voltage of the connected external power supply is directly used to charge the battery module and output to the energy storage output interface to supply power to the load. When the power type of the external power supply is a DC power supply and the output voltage of the external power supply does not match the charging voltage of the battery module to be charged, the series-parallel connection relationship between the multiple battery packs is controlled to switch, so that the multiple battery packs of the battery module form multiple charging groups, and the charging voltage of each charging group matches the output voltage of the external power supply. When the charging voltage of the charging group matches the output voltage of the external power supply, the output voltage of the connected external power supply is used to charge each charging group, and the output voltage of the connected external power supply is converted into a load power supply voltage and output to the energy storage output interface to supply power to the load. Among them, the charging voltage of the charging group matches the output voltage of the external power supply, so that the output voltage of the external power supply can directly charge the battery module without the need for voltage conversion, effectively avoiding the problem of low charging efficiency and power of the battery module due to voltage conversion caused by the output voltage of the external power supply. In addition, the output voltage of the external power supply is also converted into a load power supply voltage and output to the energy storage output interface to power the load. The technical effect of simultaneously charging the electric device and supplying power to the load therein when the power type of the external power supply is a DC power supply and the output voltage of the external power supply does not match the charging voltage of the battery module to be charged is achieved, and an additional interface is avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0045] Figure 1 It is a flow chart of the charging control method of the present invention;

[0046] Figure 2 This is a flow chart of an embodiment of a charging control method of the present invention;

[0047] Figure 3 A schematic flow chart of another embodiment of a charging control method of the present invention;

[0048] Figure 4 This is a flow chart of another embodiment of the charging control method of the present invention;

[0049] Figure 5 Schematic diagram of the circuit structure of the charging circuit of the present invention;

[0050] Figure 6 It is a schematic structural diagram of an embodiment of a charging circuit of the present invention.

[0051] Description of Figure Numbers:

[0052] 10. First switch circuit; 11. First switch; 12. Second switch; 13. Third switch; 20. Voltage conversion circuit; 30. DC conversion switch circuit; 40. Bus switch circuit; 50. Battery module; 60. DC charging terminal; 70. AC charging terminal.

[0053] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0054] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0055] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0056] In addition, the descriptions of "first", "second", etc. in the present invention are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0057] With the development of electric vehicles, the DC bus of vehicles has gradually increased from 400V to 800V. For a long time, charging speed and endurance have been the shortcomings of electric vehicles. When the high-voltage architecture of electric vehicles is increased from 400V to 800V, the charging current will be halved (P=U*I) at the same charging power, which can reduce the loss and heat generation during charging (P=I2*R), and can also reduce the cable radius, achieving the effect of reducing costs and weight.

[0058] However, the existing DC charging pile still outputs 400V DC. Therefore, in the prior art, a corresponding switch circuit is set in the battery module to change the series-parallel relationship of multiple battery packs in the battery module, thereby matching the charging voltage of the battery module with the output voltage of the DC charging pile. However, this adaptive matching method will result in the DC charging pile being unable to power the load of the electric vehicle.

[0059] Therefore, in order to solve the above problems, refer to Figure 1 The present invention provides a charging control method, which is applied to an electric device, wherein the electric device comprises a battery module and a charging circuit connected to the battery module, wherein the charging circuit has a charging input interface for connecting to an external power source and an energy storage output interface for outputting electric energy to a load of the electric device; the battery module comprises a plurality of battery packs connected in series and parallel to each other;

[0060] The charging control method comprises:

[0061] Step S100: after establishing a connection between the charging input interface and the external power source, determining the power source type of the external power source and the output voltage of the external power source based on the charging handshake information between the charging input interface and the external power source;

[0062] Step S200: when the power source type of the external power source is a DC power source and the output voltage of the external power source matches the charging voltage of the battery module to be charged, the output voltage of the connected external power source is directly used to charge the battery module and output to the energy storage output interface to supply power to the load;

[0063] Step S300: When the power type of the external power source is a DC power source and the output voltage of the external power source does not match the charging voltage of the battery module to be charged, controlling the series-parallel connection relationship between the multiple battery packs to be switched so that the multiple battery packs of the battery module form multiple charging groups, and the charging voltage of each charging group matches the output voltage of the external power source;

[0064] Step S400: When the charging voltage of the charging group matches the output voltage of the external power supply, the output voltage of the external power supply is connected to charge each charging group, and the output voltage of the connected external power supply is converted into a load power supply voltage and output to the energy storage output interface to power the load.

[0065] In this embodiment, the electric device may be an electric device such as an electric vehicle or an electric transporter; the external power supply may be a DC power supply output by a DC charging device or an AC power supply of an AC charging device. It is understandable that the electric device needs to confirm the power type of the external power supply and the output voltage of the external power supply to confirm the subsequent actions to be performed. Therefore, after the electric device establishes a physical connection between the charging input interface and the external power supply, it will establish a handshake communication with the external power supply to obtain the power type of the external power supply and the output voltage of the external power supply. Among them, take the electric device as an electric vehicle and the external power supply as an example. After the charging gun of the DC charging pile is inserted into the charging socket of the vehicle, the vehicle establishes a physical connection with the charging pile. The vehicle and the charging pile conduct preliminary communication through the control guidance circuit to determine whether both parties support the same charging standard. For example, in the CCS system, the vehicle and the charging pile will exchange PP (Proximity Pilot) signals to confirm the connection status. The vehicle will send a series of information about the status of the battery module to the charging pile, including the maximum allowable current, voltage level, battery temperature, etc. At the same time, the charging pile will also inform the vehicle of the power type, output voltage and other relevant information it can provide.

[0066] It should be understood that the charging process of the battery module requires a DC power supply of rated voltage. Therefore, when the output voltage of the external power supply connected to the charging input interface is an AC power supply or a DC power supply of non-rated voltage, the battery module needs to use a corresponding voltage conversion device to convert the output voltage of the external power supply connected to the charging input interface into a DC power supply of rated voltage to realize the charging process. When the power type of the external power supply is a DC power supply and the output voltage of the external power supply matches the charging voltage of the battery module to be charged, the electric device can determine the charging handshake information between the external power supply and the external power supply, and then perform the corresponding charging action, so that the output voltage of the external power supply directly charges the battery module and supplies power to the load of the electric device. For example, when the voltage architecture of the electric device is 800V and the output voltage of the external power supply is also 800V DC, the output voltage of the external power supply can directly charge and supply power to the battery module and the load in the electric device at the same time. Among them, because the charging voltage of the battery module is the same as the power supply voltage of the load in the electric device, the electric device only needs to use the same charging input interface to simultaneously realize the charging of the battery module and the power supply of the load in the electric device, and no additional structure is required.

[0067] In this embodiment, by setting the corresponding first switch circuit, the conduction or disconnection of the switch element in the switch circuit is adjusted, so that the series-parallel relationship between the battery packs in the battery module is adjusted. In the case where the power type of the external power supply is a DC power supply and the output voltage of the external power supply does not match the charging voltage of the battery module to be charged, the electric device will determine the switching mode of the series-parallel connection relationship between the multiple battery packs through the magnitude relationship between the output voltage of the external power supply and the charging voltage of the battery module to be charged, so that the multiple battery packs of the battery module form multiple charging groups, and the charging voltage of each charging group matches the output voltage of the external power supply. For example, when the voltage architecture of the electric device is 800V and the output voltage of the external power supply is 200V DC, the electric device can switch the series-parallel connection between the battery packs so that the four groups of 200V series battery packs in the battery module are switched to form four groups of 200V parallel charging groups. At this time, the charging voltage of each charging group matches the output voltage of the external power supply, thereby ensuring the charging efficiency and charging power of the battery module.

[0068] In this embodiment, the output voltage of the external power supply has been used to charge the battery module via the charging input interface. However, the load in the electric device still has a power supply demand. Therefore, the output voltage of the external power supply also needs to power the load in the electric device. However, the output voltage of the external power supply only matches the charging voltage of the charging group, but does not match the power supply voltage of the load. Therefore, the output voltage of the external power supply needs to pass through a corresponding voltage conversion device to match the output voltage of the external power supply with the power supply voltage of the load, thereby realizing power supply for the load in the electric device.

[0069] The technical solution of the present invention determines the power type of the external power supply and the output voltage of the external power supply through the charging handshake information between the external power supply and the external power supply after establishing a connection between the charging input interface and the external power supply. When the power type of the external power supply is a DC power supply and the output voltage of the external power supply matches the charging voltage of the battery module to be charged, the output voltage of the connected external power supply is directly used to charge the battery module and output to the energy storage output interface to supply power to the load. When the power type of the external power supply is a DC power supply and the output voltage of the external power supply does not match the charging voltage of the battery module to be charged, the series-parallel connection relationship between the multiple battery packs is controlled to switch, so that the multiple battery packs of the battery module form multiple charging groups, and the charging voltage of each charging group matches the output voltage of the external power supply. When the charging voltage of the charging group matches the output voltage of the external power supply, the output voltage of the connected external power supply is used to charge each charging group, and the output voltage of the connected external power supply is converted into a load power supply voltage and output to the energy storage output interface to supply power to the load. Among them, the charging voltage of the charging group matches the output voltage of the external power supply, so that the output voltage of the external power supply can directly charge the battery module without the need for voltage conversion, effectively avoiding the problem of low charging efficiency and power of the battery module due to the output voltage of the external power supply. In addition, the output voltage of the external power supply is also converted into a load power supply voltage and output to the energy storage output interface to power the load. The technical effect of simultaneously charging the electric device and supplying power to the load therein when the power type of the external power supply is a DC power supply and the output voltage of the external power supply does not match the charging voltage of the battery module to be charged is achieved, and an additional interface is avoided.

[0070] Referring to FIG. 2 , in one embodiment of the present invention, when the output voltage of the external power source does not match the charging voltage of the battery module to be charged, the method of controlling the series-parallel connection relationship between the multiple battery packs to switch so that the multiple battery packs of the battery module form multiple charging groups, and the charging voltage of each charging group matches the output voltage of the external power source specifically includes:

[0071] Step S310: When the output voltage of the external power source is greater than the charging voltage of the battery module to be charged, control the multiple battery packs to switch to a first connection state; in the first connection state, the multiple battery packs form a charging group connected in series;

[0072] Step S320: when the output voltage of the external power source is lower than the charging voltage of the battery module to be charged, control the plurality of battery packs to be in a second connection state; in the second connection state, the plurality of battery packs form a plurality of charging groups connected in parallel.

[0073] In this embodiment, there are two situations where the output voltage of the external power supply does not match the charging voltage of the battery module to be charged. One is that the output voltage of the external power supply is greater than the charging voltage of the battery module to be charged; the other is that the output voltage of the external power supply is less than the charging voltage of the battery module to be charged. It can be understood that the two situations where the output voltage of the external power supply does not match the charging voltage of the battery module to be charged correspond to two connection states of multiple battery packs. In the case where the output voltage of the external power supply is greater than the charging voltage of the battery module to be charged, it is necessary to increase the charging voltage of the battery module to be charged to achieve the technical effect of matching the charging voltage of the battery module to be charged with the output voltage of the external power supply. Among them, in the electric device, the way to increase the charging voltage of the battery module to be charged is to switch the parallel relationship of multiple battery packs in the battery module to a series relationship, that is, to switch multiple battery packs to the first connection state. Take the output voltage of the external power supply as 800V, and the battery module as four groups of 200V battery packs arranged in parallel as an example. The electric device increases the charging voltage of the battery module from 200V to 800V by switching four groups of 200V battery packs arranged in parallel to four groups of 200V battery packs arranged in series in sequence, thereby realizing that the output voltage of the external power supply directly supplies power to the load. When the output voltage of the external power supply is less than the charging voltage of the battery module to be charged, it is necessary to reduce the charging voltage of the battery module to be charged to achieve the technical effect that the charging voltage of the battery module to be charged matches the output voltage of the external power supply. Among them, in the electric device, the way to reduce the charging voltage of the battery module to be charged is to switch the series relationship of multiple battery packs in the battery module to a parallel relationship, that is, to switch multiple battery packs to the second connection state. Take the output voltage of the external power supply as 200V, and the battery module is a battery pack of four groups of 200V arranged in series as an example. The electric device switches four groups of 200V battery packs arranged in parallel to four groups of 200V battery packs arranged in parallel, thereby reducing the charging voltage of the battery module from 800V to 200V, thereby realizing that the output voltage of the external power supply directly supplies power to the load.

[0074] refer to Figure 3 In one embodiment of the present invention, the charging input interface has a DC charging terminal positive electrode and a DC charging terminal negative electrode, the charging circuit includes a first switch circuit, the first switch circuit includes a first switch, a second switch and a third switch; the first switch is connected in series between the two interconnected battery packs; the positive electrode of each battery pack is connected to the DC charging terminal positive electrode through the second switch, and the negative electrode of each battery pack is connected to the DC charging terminal negative electrode through the third switch;

[0075] The method of controlling the plurality of battery packs to switch to a first connection state when the output voltage of the external power supply is greater than the charging voltage of the battery module to be charged; in the first connection state, the plurality of battery packs form a charging group connected in series; and controlling the plurality of battery packs to switch to a second connection state when the output voltage of the external power supply is less than the charging voltage of the battery module to be charged; in the second connection state, the plurality of battery packs form a plurality of charging groups connected in parallel specifically includes:

[0076] Step S311: when the output voltage of the external power source is greater than the charging voltage of the battery module to be charged, controlling the first switch to be turned on, and controlling the second switch and the third switch to be turned off, so as to control the multiple battery packs to switch to the first connection state;

[0077] Step S321: when the output voltage of the external power source is lower than the charging voltage of the battery module to be charged, the second switch and the third switch are controlled to be turned on, and the first switch is controlled to be turned off, so as to control the multiple battery packs to switch to the second connection state.

[0078] In this embodiment, the number of the first switch, the second switch and the third switch can be multiple, and all can be implemented by switch devices such as contactors or relays. The first switch is a series switch in the battery module; the second switch and the third switch are parallel switches in the battery module. When the battery pack in the battery module is switched to the first connection state, that is, multiple battery packs form a charging group connected in series. At this time, the first switch will be turned on, and the second switch and the third switch will be turned off, so that the multiple battery packs in the battery module are switched to a state of being connected in series with each other, so as to increase the charging voltage of the battery module. Among them, take the output voltage of the external power supply as 800V, the battery module includes the first battery pack and the second battery pack, and the charging voltage of the first battery pack and the second battery pack is 400V as an example. At this time, the number of the first switch, the second switch and the third switch is all one group. The first switch is arranged in series between the first battery pack and the second battery pack; the first end of the second switch is connected to the positive pole of the DC charging terminal, and the second end of the second switch is connected to the positive pole of the first battery pack; the first end of the third switch is connected to the negative pole of the second battery pack, and the second end of the third switch is connected to the negative pole of the DC charging terminal. The battery device switches the first battery pack and the second battery pack to a series state by turning on the first switch and turning off the second switch and the third switch, and the charging voltage of the battery module is switched to a charging voltage of 800V. When the battery pack in the battery module is switched to the second connection state, that is, multiple battery packs form multiple charging groups connected in parallel. At this time, the first switch will be turned off, and the second switch and the third switch will be turned on, so that the multiple battery packs in the battery module are switched to a state of being connected in parallel with each other, so as to reduce the charging voltage of the battery module. Among them, take the output voltage of the external power supply as 400V, the battery module includes the first battery pack and the second battery pack, and the charging voltage of the first battery pack and the second battery pack is 400V as an example. At this time, the number of the first switch, the second switch and the third switch is a group. The first switch is arranged in series between the first battery pack and the second battery pack; the first end of the second switch is connected to the positive pole of the DC charging terminal, and the second end of the second switch is connected to the positive pole of the first battery pack; the first end of the third switch is connected to the negative pole of the second battery pack, and the second end of the third switch is connected to the negative pole of the DC charging terminal. The battery device switches the first battery pack and the second battery pack to a parallel state by turning off the first switch and turning on the second switch and the third switch. At this time, the charging voltage of the battery module is switched to a 400V charging voltage.

[0079] In one embodiment of the present invention, the charging circuit further includes a bus switch circuit; the bus switch circuit is connected in series between the battery module and the energy storage output interface;

[0080] Before controlling the series-parallel connection relationship between the plurality of battery packs to switch, the method further includes:

[0081] When the power type of the external power supply is a DC power supply and the output voltage of the external power supply does not match the charging voltage of the battery module to be charged, stop the operation of the load connected to the energy storage output interface, and control the bus switch circuit to disconnect the path between the battery module and the energy storage output interface.

[0082] In this embodiment, the bus switch circuit can be implemented by using switching devices such as contactors or relays. Among them, the bus switch circuit is serially arranged between the battery module and the energy storage output interface. The electric device realizes the power supply state of the battery module by controlling the conduction or cut-off of the bus switch circuit. When the bus switch circuit is cut off, the battery module will stop outputting power to the energy storage output interface, thereby stopping power supply to the load in the electric device; when the bus switch circuit is conducted, the battery module will output power to the energy storage output interface, thereby starting to supply power to the load in the electric device. Further, a voltage conversion circuit is also provided in the electric device, and the output end of the voltage conversion circuit is connected to the energy storage output interface. At this time, the bus switch circuit is correspondingly serially arranged between the battery module and the output end of the voltage conversion circuit to isolate the mutual interference between the battery module and the voltage conversion circuit. It can be understood that when the power type of the external power supply is a DC power supply and the output voltage of the external power supply does not match the charging voltage of the battery module to be charged, the battery module needs to switch its own series-parallel connection relationship. At this time, the battery module will no longer be able to supply power to the load in the electric device. Therefore, the electric device needs to first control the load that has a power supply connection with the battery module to stop working to avoid problems such as data loss and equipment damage caused by sudden power-off of the load. After the load that has a power supply connection with the battery module stops working, the electric device will control the bus switch circuit to disconnect the path between the battery module and the energy storage output interface to prevent the output voltage of the external power supply with a voltage inconsistent with the load power supply voltage from being input to the energy storage output interface.

[0083] In an embodiment of the present invention, the charging input interface includes a DC input terminal for accessing a DC charging voltage and an AC charging terminal for accessing an AC charging voltage;

[0084] After the step of determining the power type of the external power supply and the magnitude of the output voltage of the external power supply based on the charging handshake information with the external power supply, the method further includes:

[0085] When the power type of the external power supply is an AC power supply, convert the output voltage of the accessed external power supply into the charging voltage corresponding to the battery module and the load power supply voltage for the load to charge the battery module and supply power to the load.

[0086] In this embodiment, the electric device has two charging modes: DC fast charging and AC slow charging, that is, the charging input interface of the electric device includes a DC input terminal for accessing a DC charging voltage and an AC charging terminal for accessing an AC charging voltage, so that the electric device can be charged under different power supply environments. It can be seen from the above that the charging of the battery module and the power supply voltage of the load in the electric device are both DC voltages. Therefore, the AC voltage output by the AC charging terminal in the charging input interface needs to pass through a voltage conversion circuit to convert the AC voltage into a corresponding DC voltage to meet the charging requirements of the battery module and the power supply requirements of the load in the electric device. It can be understood that when the electric device is in a normal working state, the charging voltage of the battery module is consistent with the load power supply voltage of the load in the electric device. Therefore, when the AC charging voltage is input to the AC charging terminal in the charging input interface for charging, the series-parallel connection relationship of the multiple battery packs in the battery module does not need to be switched.

[0087] refer to Figure 4 , in one embodiment of the present invention, the charging circuit further includes a voltage conversion circuit for voltage conversion and a detection circuit for detecting the input terminal voltage of the voltage conversion circuit;

[0088] Before the step of converting the output voltage of the connected external power supply into a load power supply voltage and outputting the voltage to the energy storage output interface, the method further includes:

[0089] Step S500: Acquire detection information of the input end of the voltage conversion circuit;

[0090] Step S600: when the detection information does not match the output voltage of the external power supply, a fault signal is output.

[0091] In this embodiment, after the electric device establishes a physical connection between the charging input interface and the external power supply, it has acquired the power type of the external power supply and the output voltage of the external power supply by establishing a handshake communication with the external power supply. However, when the power type of the external power supply is a DC power supply and the output voltage of the external power supply does not match the charging voltage of the battery module to be charged, or when the power type of the power supply is an AC power supply, the electric device needs to accurately control the voltage conversion circuit to convert the input voltage into the corresponding charging voltage and / or load power supply voltage according to the voltage information input to the voltage conversion circuit. Among them, in order to avoid the electric device and the external power supply to establish a handshake communication to obtain the power type of the external power supply and the output voltage of the external power supply, and to obtain its voltage frequency when the power type of the external power supply is an AC power supply, the electric device also sets a detection circuit at the input end of the voltage conversion circuit to obtain the detection information that needs to be converted by the voltage conversion circuit, so as to accurately control the operation of the voltage conversion circuit. Furthermore, when the detection information does not match the output voltage of the external power supply, that is, when the power type of the external power supply and the output voltage of the external power supply obtained by the electric device and the external power supply to establish handshake communication do not match the detection information output by the detection circuit, it indicates that there is a communication error in the handshake communication between the electric device and the external power supply or there is a fault in the detection circuit. At this time, the electric device will confirm the information of the mismatch, output a corresponding fault signal, and stop the output of the output voltage of the external power supply. It is understandable that this mismatch state may cause the voltage converted and output by the voltage conversion circuit to not match the charging voltage of the battery module and / or the load power supply voltage of the load in the electric device, thereby causing charging safety hazards.

[0092] refer to Figure 5 and Figure 6 The present invention also provides a charging circuit, which is applied to an electric device, wherein the electric device includes a battery module 50, wherein the battery module 50 has a plurality of battery packs connected in series and parallel to each other; the charging circuit includes: a charging input interface, an energy storage output interface, a first switch circuit 10, a voltage conversion circuit 20 and a control circuit;

[0093] The charging input interface is used to access the output voltage of an external power source;

[0094] The energy storage output interface is used to output electric energy to the electric device load;

[0095] A control circuit (not shown in the figure), configured to determine the power type of the external power source and the output voltage of the external power source based on the charging handshake information between the charging input interface and the external power source after establishing a connection between the charging input interface and the external power source;

[0096] When the power type of the external power source is a DC power source and the output voltage of the external power source matches the charging voltage of the battery module 50 to be charged, the output voltage of the connected external power source is directly used to charge the battery module 50 and output to the energy storage output interface to supply power to the load;

[0097] When the power type of the external power source is a DC power source and the output voltage of the external power source does not match the charging voltage of the battery module 50 to be charged, the first switch circuit 10 is controlled to switch the series-parallel connection relationship between the multiple battery packs, so that the multiple battery packs of the battery module 50 form multiple charging groups, and the charging voltage of each charging group matches the output voltage of the external power source;

[0098] When the charging voltage of the charging group matches the output voltage of the external power supply, the output voltage of the external power supply is connected to charge each charging group, and the voltage conversion circuit 20 is controlled to convert the output voltage of the connected external power supply into a load power supply voltage and output it to the energy storage output interface to power the load.

[0099] In this embodiment, the control circuit can be implemented by a main controller, such as SOC (System On Chip), MCU (Microcontroller Unit), DSP (Digital Signal Process), FPGA (Field Programmable Gate Array), etc. Among them, the control circuit establishes a corresponding communication connection with the charging input interface to achieve handshake communication with the external power supply, and then obtains the power type of the external power supply and the output voltage of the external power supply. After the control circuit obtains the power type and output voltage of the external power supply, the control circuit can output the corresponding first switch 11 control signal to the first switch circuit 10 and / or the voltage conversion control signal to the voltage conversion circuit 20, so that the battery module 50 obtains the corresponding charging voltage and the load power supply voltage of the load in the electric device.

[0100] In this embodiment, the first switch circuit 10 can be implemented by multiple contactors or multiple relays. The first switch circuit 10 switches the series-parallel connection relationship of the battery module 50 by receiving the corresponding first switch 11 control signal output by the control circuit.

[0101] In this embodiment, the voltage conversion circuit 20 can be implemented by a rectifier circuit, a boost circuit, etc. The input end of the voltage conversion circuit 20 is electrically connected to the charging input interface to obtain the output voltage of the external power supply; the controlled end of the voltage conversion circuit 20 is electrically connected to the control circuit to obtain the corresponding voltage conversion control signal output by the control circuit, so as to accurately convert the input voltage into the corresponding output voltage and output it. Taking the electric device as an electric car as an example, the voltage conversion circuit 20 can be implemented by a vehicle charger. Among them, the power topology of the vehicle charger is divided into two stages. The front stage is a three-phase six-switch PFC, which converts the input AC voltage into a DC voltage, specifically including a first inductor L1, a second inductor L2, a third inductor L3, a first switch tube Q1, a second switch tube Q2, a third switch tube Q3, a fourth switch tube Q4, a fifth switch tube Q5, a sixth switch tube Q6, a seventh switch tube Q7, and an eighth switch tube Q8; the rear stage is a CLLC isolated DC-DC, which can convert the DC voltage into the charging voltage and The load charging voltage required by the load in the electric vehicle specifically includes the tenth switch K10, the first capacitor C1, the second capacitor C2, the third capacitor C3, the fourth capacitor C4, the fifth capacitor C5, the sixth capacitor C6, the fourth inductor L4, the fifth inductor L5, the sixth inductor L6, the transformer T1, the ninth switch tube Q9, the tenth switch tube Q10, the eleventh switch tube Q11, the twelfth switch tube Q12, the thirteenth switch tube Q13, the fourteenth switch tube Q14, the fifteenth switch tube Q15, and the sixteenth switch tube Q16.

[0102] refer to Figure 5 In one embodiment of the present invention, the charging input interface has a positive pole of a DC charging terminal 60 and a negative pole of a DC charging terminal 60; the first switch circuit 10 further includes a first switch 11, a second switch 12 and a third switch 13; the first switch 11 is connected in series between the two interconnected battery packs; the positive pole of each battery pack is connected to the positive pole of the DC charging terminal 60 through the second switch 12, and the negative pole of each battery pack is connected to the negative pole of the DC charging terminal 60 through the third switch 13;

[0103] The control circuit is further used to control the first switch 11 to be turned on and the second switch 12 and the third switch 13 to be turned off when the output voltage of the external power supply is greater than the charging voltage of the battery module 50 to be charged; and to control the second switch 12 and the third switch 13 to be turned on and the first switch 11 to be turned off when the output voltage of the external power supply is less than the charging voltage of the battery module 50 to be charged.

[0104] In this embodiment, the number of the first switch 11, the second switch 12 and the third switch 13 can be multiple, and their controlled ends are electrically connected to the control circuit respectively. Among them, the first switch 11, the second switch 12 and the third switch 13 can all be implemented by switch devices such as contactors or relays. The first switch 11 is a series switch in the battery module 50; the second switch 12 and the third switch 13 are parallel switches in the battery module 50. When the battery pack in the battery module 50 is switched to the first connection state, that is, multiple battery packs form a charging group connected in series. At this time, the first switch 11 will be turned on, and the second switch 12 and the third switch 13 will be turned off, so that the multiple battery packs in the battery module 50 are switched to a state of being connected in series with each other, so as to increase the charging voltage of the battery module 50. Among them, take the output voltage of the external power supply as 800V, the battery module 50 includes the first battery pack and the second battery pack, and the charging voltages of the first battery pack and the second battery pack are both 400V as an example. At this time, the number of the first switch 11, the second switch 12 and the third switch 13 is one group. The first switch 11 is arranged in series between the first battery pack and the second battery pack; the first end of the second switch 12 is connected to the positive electrode of the DC charging terminal 60, and the second end of the second switch 12 is connected to the positive electrode of the first battery pack; the first end of the third switch 13 is connected to the negative electrode of the second battery pack, and the second end of the third switch 13 is connected to the negative electrode of the DC charging terminal 60. The battery device switches the first battery pack and the second battery pack to a series state by turning on the first switch 11 and turning off the second switch 12 and the third switch 13. At this time, the charging voltage of the battery module 50 is switched to a charging voltage of 800V. When the battery packs in the battery module 50 are switched to the second connection state, that is, multiple battery packs form multiple charging groups connected in parallel. At this time, the first switch 11 will be turned off, and the second switch 12 and the third switch 13 will be turned on, so that the multiple battery packs in the battery module 50 are switched to a state of being connected in parallel with each other, so as to reduce the charging voltage of the battery module 50. Here, the output voltage of the external power supply is 400V, the battery module 50 includes a first battery pack and a second battery pack, and the charging voltage of the first battery pack and the second battery pack is 400V. At this time, the number of the first switch 11, the second switch 12 and the third switch 13 is a group. The first switch 11 is arranged in series between the first battery pack and the second battery pack; the first end of the second switch 12 is connected to the positive pole of the DC charging terminal 60, and the second end of the second switch 12 is connected to the positive pole of the first battery pack; the first end of the third switch 13 is connected to the negative pole of the second battery pack, and the second end of the third switch 13 is connected to the negative pole of the DC charging terminal 60. The battery device switches the first battery pack and the second battery pack to a parallel state by turning off the first switch 11 and turning on the second switch 12 and the third switch 13. At this time, the charging voltage of the battery module 50 is switched to a charging voltage of 400V.

[0105] refer to Figure 5 and Figure 6 In one embodiment of the present invention, the charging input interface includes a DC charging terminal 60 for connecting to a DC charging voltage and an AC charging terminal 70 for connecting to an AC charging voltage; the voltage conversion circuit 20 also includes a DC conversion switch circuit 30, a first end of the DC conversion switch circuit 30 is electrically connected to the DC charging terminal 60, a controlled end of the DC conversion switch circuit 30 is electrically connected to the control circuit, and a second end of the DC conversion switch circuit 30 is electrically connected to the AC charging terminal 70;

[0106] The control circuit is also used to control the conduction state of the DC conversion switch circuit 30 so that the DC charging voltage is converted into a load power supply voltage and output to the energy storage output interface to supply power to the load.

[0107] It should be understood that in a conventional charging circuit of an electric device, the input end of the voltage conversion circuit 20 is directly connected to the AC charging end 70, while the DC charging end 60 is connected to the busbar between the battery module 50 and the energy storage output end. Therefore, if the DC charging voltage input by the DC charging end 60 needs to be converted and output by the voltage conversion circuit 20, it is necessary to additionally set a corresponding interface or set a corresponding circuit structure.

[0108] In this embodiment, the DC conversion switch circuit 30 can be implemented by a contactor or a relay. Among them, the DC conversion switch circuit 30 is arranged between the DC charging terminal 60 and the AC charging terminal 70. When selecting, it can adopt specifications lower than the first switch 11, the second switch 12 and the third switch 13 to reduce costs. When the charging voltage of the charging group matches the output voltage of the external power supply, the control circuit will control the bus switch circuit 40 to disconnect to isolate the charging work of the battery module 50 and the power supply work of the load of the electric device. At this time, the DC voltage input from the charging input terminal will charge the battery module 50. The power supply work of the load of the electric device requires the control circuit to control the DC conversion switch circuit 30 to conduct the path between the DC charging terminal 60 and the AC charging terminal 70, and the effect of DC input to the voltage conversion circuit 20 is achieved by using the path between the AC charging terminal 70 and the input terminal of the voltage conversion circuit 20. It should be supplemented that the charging input interface only has either current charging or AC charging.

[0109] refer to Figure 5In one embodiment of the present invention, the charging circuit further includes a bus switch circuit 40, a first end of the bus switch circuit 40 is electrically connected to the battery module 50, a controlled end of the bus switch circuit 40 is electrically connected to the control circuit, and a second end of the bus switch circuit 40 is electrically connected to the energy storage output interface; the bus switch circuit 40 is used to turn on or off the path between the battery module 50 and the energy storage output interface according to a corresponding bus switch control signal output by the control circuit.

[0110] In this embodiment, the bus switch circuit 40 can be implemented by a contactor or a relay. It can be understood that the bus switch circuit 40 is used to turn on or off the path between the battery module 50 and the energy storage output interface, and the path between the battery module 50 and the energy storage output interface has a positive pole connection bus and a negative pole connection bus. Therefore, the bus switch circuit 40 needs to include at least two groups of switching devices, which are respectively arranged in series on the positive pole connection bus and the negative pole connection bus. Further, the bus switch circuit 40 is arranged in series between the battery module 50 and the output end of the voltage conversion circuit 20 to achieve isolation between the charging work of the battery module 50 and the power supply work of the load in the electric device.

[0111] In one embodiment of the present invention, the charging circuit further includes a detection circuit, the input end of the detection circuit is electrically connected to the input end of the voltage conversion circuit 20, and the output end of the detection circuit is electrically connected to the control circuit;

[0112] The control circuit is further used to control the detection circuit to obtain detection information of the input end of the voltage conversion circuit 20; and output a fault signal when the detection information does not match the output voltage of the external power supply.

[0113] In this embodiment, the detection circuit can be implemented by a voltage detection circuit and a frequency detection circuit. The detection circuit obtains the magnitude and frequency of the voltage at the input end of the voltage conversion circuit 20, thereby outputting corresponding detection information to the control circuit. The control circuit obtains the detection signal and outputs the corresponding voltage conversion control signal to the voltage conversion circuit 20, so that the voltage conversion circuit 20 accurately outputs the corresponding charging voltage and / or load power supply voltage. In addition, the control circuit can also match and confirm the detection information with the information obtained by the handshake communication of the external power supply to confirm whether there is a communication error in the handshake communication between the electric device and the external power supply or whether there is a detection fault in the detection circuit.

[0114] The present invention further provides an electric device, the electric device comprising a battery module 50 and any of the above-mentioned charging circuits. It is worth noting that since the electric device of the present invention is based on the above-mentioned charging circuit, the embodiments of the electric device of the present invention include all technical solutions of all the embodiments of the above-mentioned charging circuit, and the technical effects achieved are also exactly the same, which will not be repeated here.

[0115] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A charging control method, applied to an electric device, characterized in that: The electric device comprises a battery module and a charging circuit connected to the battery module, wherein the charging circuit has a charging input interface for connecting to an external power source and an energy storage output interface for outputting electric energy to a load of the electric device; The battery module has a plurality of battery packs connected in series and parallel to each other; The charging control method comprises: After establishing a connection between the charging input interface and the external power source, determining the power source type of the external power source and the output voltage of the external power source based on the charging handshake information between the charging input interface and the external power source; When the power type of the external power supply is a DC power supply and the output voltage of the external power supply matches the charging voltage of the battery module to be charged, the output voltage of the connected external power supply is directly used to charge the battery module and output to the energy storage output interface to supply power to the load; When the power type of the external power source is a DC power source and the output voltage of the external power source does not match the charging voltage of the battery module to be charged, the series-parallel connection relationship between the multiple battery packs is controlled to switch so that the multiple battery packs of the battery module form multiple charging groups, and the charging voltage of each charging group matches the output voltage of the external power source; When the charging voltage of the charging group matches the output voltage of the external power supply, the output voltage of the external power supply is connected to charge each charging group, and the output voltage of the external power supply is converted into a load power supply voltage and output to the energy storage output interface to power the load.

2. The charging control method according to claim 1, characterized in that: When the output voltage of the external power source does not match the charging voltage of the battery module to be charged, the method of controlling the series-parallel connection relationship between the multiple battery packs to switch so that the multiple battery packs of the battery module form multiple charging groups, and the charging voltage of each charging group matches the output voltage of the external power source specifically includes: When the output voltage of the external power source is greater than the charging voltage of the battery module to be charged, the plurality of battery packs are controlled to switch to a first connection state; in the first connection state, the plurality of battery packs form a charging group connected in series; When the output voltage of the external power source is lower than the charging voltage of the battery module to be charged, the plurality of battery packs are controlled to be in a second connection state; in the second connection state, the plurality of battery packs form a plurality of charging groups connected in parallel.

3. The charging control method according to claim 2, characterized in that: The charging input interface has a DC charging positive terminal and a DC charging negative terminal, the charging circuit includes a first switch circuit, the first switch circuit includes a first switch, a second switch and a third switch; the first switch is connected in series between the two interconnected battery packs; the positive electrode of each battery pack is connected to the DC charging positive terminal through the second switch, and the negative electrode of each battery pack is connected to the DC charging negative terminal through the third switch; When the output voltage of the external power source is greater than the charging voltage of the battery module to be charged, the multiple battery packs are controlled to switch to the first connection state; in the first connection state, the multiple battery packs form a charging group connected in series; when the output voltage of the external power source is less than the charging voltage of the battery module to be charged, the multiple battery packs are controlled to be in the second connection state; In the second connection state, the method of forming a plurality of charging groups connected in parallel with the plurality of battery packs specifically includes: When the output voltage of the external power supply is greater than the charging voltage of the battery module to be charged, the first switch is controlled to be turned on, and the second switch and the third switch are controlled to be turned off, so as to control the multiple battery packs to switch to the first connection state; When the output voltage of the external power source is lower than the charging voltage of the battery module to be charged, the second switch and the third switch are controlled to be turned on, and the first switch is controlled to be turned off, so as to control the multiple battery packs to switch to the second connection state.

4. The charging control method according to claim 3, characterized in that: The charging circuit also includes a bus switch circuit; the bus switch circuit is connected in series between the battery module and the energy storage output interface; Before controlling the series-parallel connection relationship between the plurality of battery packs to switch, the method further includes: When the power type of the external power supply is a DC power supply and the output voltage of the external power supply does not match the charging voltage of the battery module to be charged, the load connected to the energy storage output interface is stopped, and the bus switch circuit is controlled to disconnect the path between the battery module and the energy storage output interface.

5. The charging control method according to claim 1, characterized in that: The charging input interface includes a DC input terminal for connecting to a DC charging voltage and an AC charging terminal for connecting to an AC charging voltage; After the step of determining the power type of the external power source and the output voltage of the external power source based on the charging handshake information between the external power source and the external power source, the method further includes: When the power type of the external power source is an AC power source, the output voltage of the connected external power source is converted into a charging voltage of the corresponding battery module and a load power supply voltage of the load to charge the battery module and supply power to the load.

6. The charging control method according to claim 1, characterized in that: The charging circuit further includes a voltage conversion circuit for voltage conversion and a detection circuit for detecting the input terminal voltage of the voltage conversion circuit; Before the step of converting the output voltage of the connected external power supply into a load power supply voltage and outputting the voltage to the energy storage output interface, the method further includes: Acquiring detection information of an input terminal of a voltage conversion circuit; In the case where the detection information does not match the output voltage of the external power supply, a fault signal is output.

7. A charging circuit, applied to an electric device, characterized in that: The electric device includes a battery module having a plurality of battery packs connected in series and parallel to each other; The charging circuit includes: a charging input interface, an energy storage output interface, a first switch circuit, a voltage conversion circuit and a control circuit; The charging input interface is used to access the output voltage of an external power source; The energy storage output interface is used to output electric energy to the electric device load; A control circuit, configured to determine the power type of the external power source and the output voltage of the external power source based on charging handshake information between the charging input interface and the external power source after establishing a connection between the charging input interface and the external power source; When the power type of the external power supply is a DC power supply and the output voltage of the external power supply matches the charging voltage of the battery module to be charged, the output voltage of the connected external power supply is directly used to charge the battery module and output to the energy storage output interface to supply power to the load; When the power type of the external power source is a DC power source and the output voltage of the external power source does not match the charging voltage of the battery module to be charged, the first switch circuit is controlled to switch the series-parallel connection relationship between the multiple battery packs, so that the multiple battery packs of the battery module form multiple charging groups, and the charging voltage of each charging group matches the output voltage of the external power source; When the charging voltage of the charging group matches the output voltage of the external power supply, the output voltage of the external power supply is connected to charge each charging group, and the voltage conversion circuit is controlled to convert the output voltage of the connected external power supply into a load power supply voltage and output it to the energy storage output interface to power the load.

8. The charging circuit according to claim 7, characterized in that: The charging input interface has a DC charging positive terminal and a DC charging negative terminal; the first switch circuit also includes a first switch, a second switch and a third switch; the first switch is connected in series between the two interconnected battery packs; the positive electrode of each battery pack is connected to the DC charging positive terminal through the second switch, and the negative electrode of each battery pack is connected to the DC charging negative terminal through the third switch; The control circuit is further used to control the first switch to be turned on and the second switch and the third switch to be turned off when the output voltage of the external power supply is greater than the charging voltage of the battery module to be charged; and to control the second switch and the third switch to be turned on and the first switch to be turned off when the output voltage of the external power supply is less than the charging voltage of the battery module to be charged.

9. The charging circuit according to claim 7, characterized in that: The charging input interface includes a DC charging terminal for connecting to a DC charging voltage and an AC charging terminal for connecting to an AC charging voltage; the voltage conversion circuit also includes a DC conversion switch circuit, a first end of the DC conversion switch circuit is electrically connected to the DC charging terminal, a controlled end of the DC conversion switch circuit is electrically connected to the control circuit, and a second end of the DC conversion switch circuit is electrically connected to the AC charging terminal; Wherein, the control circuit is also used to control the conduction state of the DC conversion switch circuit, so that the DC charging voltage is converted into a load power supply voltage and output to the energy storage output interface to supply power to the load.

10. The charging circuit according to claim 7, characterized in that: The charging circuit also includes a bus switch circuit, a first end of the bus switch circuit is electrically connected to the battery module, a controlled end of the bus switch circuit is electrically connected to the control circuit, and a second end of the bus switch circuit is electrically connected to the energy storage output interface; the bus switch circuit is used to turn on or off the path between the battery module and the energy storage output interface according to a corresponding bus switch control signal output by the control circuit.

11. The charging circuit according to claim 7, characterized in that: The charging circuit further comprises a detection circuit, an input end of the detection circuit is electrically connected to an input end of the voltage conversion circuit, and an output end of the detection circuit is electrically connected to the control circuit; The control circuit is further used to control the detection circuit to obtain detection information of the input end of the voltage conversion circuit; when the detection information does not match the output voltage of the external power supply, a fault signal is output.

12. An electric device, characterized in that: The electric device comprises a battery module and a charging circuit as claimed in any one of claims 7 to 11.

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