Charging circuit, battery device, power supply device and power supply method

Abstract

A charging circuit includes a first AC-DC conversion circuit, an AC end of which is configured to be connected to an AC power supply; the direct current end of the first AC-DC conversion circuit is connected to the first end of the first DC-DC conversion circuit, and the second end of the first DC-DC conversion circuit is configured to be connected to a battery module; the charging circuit is configured as follows: in response to the condition that the battery module meets a first charging condition, the alternating current power supply charges the battery module through the first AC-DC conversion circuit and the first DC-DC conversion circuit; wherein the first charging condition comprises that the voltage of a battery cell in the battery module is smaller than a voltage threshold value, and / or the temperature of the battery cell is lower than a temperature threshold value.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a charging circuit, battery device, power supply device, and power supply method. Background Technology

[0002] Battery modules require charging. However, charging a lithium-ion battery when its voltage or temperature is too low can easily cause lithium-ion metal to deposit and form dendrites, leading to safety issues such as internal short circuits. Summary of the Invention

[0003] In view of this, this application provides a charging circuit, battery device, power supply device and power supply method, which can realize low-current charging of battery modules and avoid safety risks such as metal deposition and dendrite formation during battery module charging that could cause internal short circuits in the battery.

[0004] This application provides a charging circuit in a first aspect. The charging circuit includes: a first AC-DC converter circuit, the AC terminal of which is configured to be connected to an AC power source; and a first DC-DC converter circuit, the DC terminal of which is connected to a first terminal of the first AC-DC converter circuit, and a second terminal of the first DC-DC converter circuit configured to be connected to a battery module; the charging circuit is configured to: in response to the battery module meeting a first charging condition, the AC power source charges the battery module through the first AC-DC converter circuit and the first DC-DC converter circuit; wherein the first charging condition includes: the voltage of the battery cell in the battery module is less than a voltage threshold, and / or, the temperature of the battery cell is lower than a temperature threshold.

[0005] Understandably, when the voltage of a cell in a battery module is less than a voltage threshold, it indicates that the battery module is in a low-voltage state. When the temperature of a cell is less than a temperature threshold, it indicates that the battery module is in a low-temperature state. To ensure safety, the battery module needs to undergo trickle pre-charging when it is at low voltage or low temperature. This application addresses this by setting up a first AC-DC converter circuit and a first DC-DC converter circuit. When the battery module is at low voltage or low temperature, AC power is used to charge the battery module through these circuits. The first AC-DC converter circuit converts the AC voltage of the AC power supply into DC voltage, which is then supplied to the first DC-DC converter circuit. The first DC-DC converter circuit can continuously and over a wide range adjust the DC voltage and current, thereby outputting a constant small current to charge the battery module. This meets the trickle charging requirements of the battery module, ensuring safe and reliable charging and avoiding safety risks such as metal deposition and dendrite formation during charging that could lead to internal short circuits.

[0006] In one or more embodiments, the charging circuit includes: a second AC-DC converter circuit, the AC terminal of which is configured to be connected to an AC power source; a second DC-DC converter circuit, the DC terminal of which is connected to a first terminal of which is configured to be connected to a battery module; the charging circuit is configured to: in response to the battery module meeting a second charging condition, the AC power source charges the battery module through the second AC-DC converter circuit and the second DC-DC converter circuit; wherein the second charging condition includes: the voltage of the battery cell in the battery module is greater than a voltage threshold, and the temperature of the battery cell is greater than a temperature threshold.

[0007] Understandably, the voltage of the cells in the battery module is greater than the voltage threshold, and the temperature of the cells is greater than the temperature threshold. This indicates that the voltage of each cell in the battery module is higher than the voltage threshold, and the battery module will not be charged at low temperatures. In order to improve the charging efficiency of the battery module and quickly charge the battery module to a fully charged state, the charging conditions of the battery module change from the first charging condition to the second charging condition. The fast charging of the battery module is achieved by setting a second AC-DC conversion circuit and a second DC-DC conversion circuit.

[0008] In one or more embodiments, the first AC-DC converter circuit includes an isolated AC-DC converter circuit. The second AC-DC converter circuit includes a full-bridge PFC circuit. The first DC-DC converter circuit is a bidirectional DC-DC converter circuit; preferably, the first DC-DC converter circuit includes a non-isolated DC-DC converter circuit. It is understood that the non-isolated DC-DC converter circuit has a wider voltage regulation range for low voltages than the isolated DC-DC converter circuit, enabling it to achieve lower output voltages and smaller charging currents. Therefore, using a non-isolated DC-DC converter circuit as the first DC-DC converter circuit can well adapt to the low-voltage trickle charging requirements of the battery module, ensuring the realization of the low-voltage trickle charging function. The second DC-DC converter circuit is an isolated DC-DC converter circuit; preferably, the second DC-DC converter circuit includes a dual active bridge converter circuit, an LLC converter circuit, or a CLLC converter circuit. The first terminal of the second DC-DC converter circuit is connected to a high-voltage AC power supply via a second AC-DC converter circuit, and the second terminal of the second DC-DC converter circuit is connected to a low-voltage battery module. Using an isolated DC-DC converter circuit achieves electrical isolation between the low-voltage and high-voltage sides, meeting safety requirements. Furthermore, isolated AC-DC converter circuits, bidirectional DC-DC converter circuits, and isolated DC-DC converter circuits can be implemented in various ways. Therefore, the implementation of the first AC-DC converter circuit, the first DC-DC converter circuit, the second AC-DC converter circuit, and the second DC-DC converter circuit can be very flexible, reducing the design complexity of the charging circuit in this application.

[0009] In one or more embodiments, the charging circuit includes: a control circuit, wherein a first AC-DC converter circuit, a second AC-DC converter circuit, a first DC-DC converter circuit, and a second DC-DC converter circuit are respectively connected to the control circuit; and a current sampling circuit connected to the first DC-DC converter circuit and the control circuit, wherein the current sampling circuit is configured to sample the charging current of the battery module charged by the AC power supply through the first AC-DC converter circuit and the first DC-DC converter circuit. Furthermore, the control circuit can regulate the operation of the first DC-DC converter circuit based on the charging current sampled in real time by the current sampling circuit, so that the charging current output by the first DC-DC converter circuit can be adjusted to meet the current requirements of trickle charging.

[0010] In one or more embodiments, the charging circuit includes: a first unidirectional conductor, a second unidirectional conductor, a voltage conversion circuit, and a third DC-DC converter circuit; the input terminal of the voltage conversion circuit, the first terminal of the third DC-DC converter circuit, the first terminal of the first DC-DC circuit, and the DC terminal of the first AC-DC converter circuit are connected to a first node; the first unidirectional conductor is disposed between the DC terminal of the first AC-DC converter circuit and the first node, and the first unidirectional conductor is used to limit the current from the DC terminal of the first AC-DC converter circuit to the first node; the first terminal of the second unidirectional conductor is connected to the first node, and the second terminal of the second unidirectional conductor is connected to the input terminal of the voltage conversion circuit and the first terminal of the third DC-DC converter circuit, and the second unidirectional conductor is used to limit the current from the first node to the voltage conversion circuit and the third DC-DC converter circuit. Based on this circuit structure, when the battery module has discharge capability, it can power the voltage conversion circuit and the third DC-DC conversion circuit through the first DC-DC converter circuit. Under the first charging condition, the battery module utilizes the first DC-DC converter circuit to achieve trickle charging, thus reusing the first DC-DC converter circuit and reducing hardware costs. Furthermore, when the battery module does not have discharge capability, external AC power can be converted to DC power through the first AC-DC converter circuit, thereby powering the voltage conversion circuit and the third DC-DC converter circuit. Therefore, the first AC-DC converter circuit is reused for trickle charging of the battery module and for powering the voltage conversion circuit and the third DC-DC converter circuit.

[0011] A second aspect of this application provides a battery device, including a battery module and a charging circuit as described in the first aspect or any embodiment of the first aspect.

[0012] A third aspect of this application provides a power supply device, including the battery device described in the second aspect above. The power supply device can store electrical energy by charging the battery device, and can also use the electrical energy stored in the battery device to supply power to external devices.

[0013] The fourth aspect of this application provides a power supply method applied to the charging circuit described in the first aspect or any embodiment of the first aspect. The method includes: in response to the battery module meeting a first charging condition, controlling a first AC-DC conversion circuit and a first DC-DC conversion circuit to operate, so that AC power is used to charge the battery module through the first AC-DC conversion circuit and the first DC-DC conversion circuit, thereby realizing small-current charging (i.e. trickle charging) of the battery module.

[0014] In one or more embodiments, the method further includes: in response to the battery module meeting a second charging condition, controlling the second AC-DC conversion circuit and the second DC-DC conversion circuit to operate, so that the AC power supply charges the battery module through the second AC-DC conversion circuit and the second DC-DC conversion circuit, thereby quickly charging the battery module.

[0015] In one or more embodiments, the method further includes: in response to the battery module meeting the first charging condition, controlling the second terminal of the first DC-DC converter circuit to output a constant charging current, thereby realizing trickle charging of the battery module, which can reduce the safety risks of the battery module during the charging process and is beneficial to the performance and service life of the battery module.

[0016] In one or more embodiments, the method further includes: in response to the battery module meeting a first charging condition and the voltage of the battery module being higher than the output voltage of the first AC-DC converter circuit, controlling the first DC-DC converter circuit to operate in boost mode, such that the voltage output at the second terminal of the first DC-DC converter circuit is higher than the output voltage of the first AC-DC converter circuit; or, in response to the battery module meeting the first charging condition and the voltage of the battery module being lower than the output voltage of the first AC-DC converter circuit, controlling the first DC-DC converter circuit to operate in buck mode, such that the voltage output at the second terminal of the first DC-DC converter circuit is lower than the output voltage of the first AC-DC converter circuit. In other words, in scenarios where the battery module is charging at low voltage or low temperature, the first DC-DC converter circuit can operate in an appropriate working mode according to the voltage conditions of the battery module and the first AC-DC converter circuit. This allows the voltage output from the second terminal of the first DC-DC converter circuit to match the current voltage of the battery module, thus enabling the battery module cells to be charged smoothly and safely. This avoids situations where the charging voltage is lower than the current voltage of the battery module, preventing the battery module from being unable to be charged, or where the charging current is much higher than the current that the battery module can currently withstand, leading to safety risks such as metal deposition and dendrite formation in the battery module. Therefore, this is beneficial to charging safety.

[0017] In one or more embodiments, the method further includes: in response to the battery module meeting discharge conditions, controlling a first DC-DC converter circuit to operate, wherein the battery module supplies power to a voltage conversion circuit and a third DC-DC converter circuit through the first DC-DC converter circuit; the discharge conditions include: the minimum voltage of the battery cell in the battery module is greater than the discharge cutoff voltage of the battery cell, and the temperature of the battery cell is within the discharge temperature range. That is, in scenarios where the battery module has discharge capability, the battery module is preferentially used to supply power to the voltage conversion circuit and the third DC-DC converter circuit through the first DC-DC converter circuit.

[0018] In one or more embodiments, the method further includes: responding to the battery module meeting the discharge conditions and the battery module voltage being higher than the output voltage of the first AC-DC converter circuit, controlling the first terminal of the first DC-DC converter circuit to output a discharge voltage, the discharge voltage being lower than the battery module voltage; or, responding to the battery module meeting the discharge conditions and the battery module voltage being lower than the output voltage of the first AC-DC converter circuit, controlling the first terminal of the first DC-DC converter circuit to output a discharge voltage, the discharge voltage being higher than the battery module voltage. In other words, in the scenario of battery module discharge, the first DC-DC converter circuit can output a suitable discharge voltage according to the battery module voltage and the output voltage specification of the first AC-DC converter circuit. This design can reduce the voltage difference between the voltage output at the second terminal of the first DC-DC converter circuit and the output voltage specification of the first AC-DC converter circuit, making the voltage output at the second terminal of the first DC-DC converter circuit close to or equal to the output voltage specification of the first AC-DC converter circuit, thus avoiding safety risks such as current backflow into the first AC-DC converter circuit.

[0019] Furthermore, the technical effects brought about by any of the embodiments in the second to fourth aspects can be referred to the technical effects brought about by the embodiments in the first aspect, and will not be repeated here. Attached Figure Description

[0020] Figure 1 This is a structural block diagram of the charging circuit provided in this application.

[0021] Figure 2 This is a schematic diagram of a charging circuit provided in some optional embodiments of this application.

[0022] Figure 3 This is a schematic diagram of a charging circuit provided in some other optional embodiments of this application.

[0023] Figure 4 This is a schematic diagram of a charging circuit provided in some other optional embodiments of this application.

[0024] Figure 5 This is a schematic diagram of the battery module in this application being charged.

[0025] Figure 6 This is a schematic diagram of the battery module in this application discharging.

[0026] Figure 7 This is a schematic diagram of a battery device provided in this application.

[0027] Figure 8 This is a schematic diagram of a power supply device provided in this application.

[0028] Explanation of main component symbols Charging circuit-100, first AC-DC converter circuit-10, first DC-DC converter circuit-20, control circuit-30. Second AC-DC converter circuit-40, second DC-DC converter circuit-50, voltage conversion circuit-60 Third DC-DC converter circuit - 70, first drive circuit - 80, second drive circuit - 90, AC power supply - 200. Battery module-300, battery equipment-400, power supply equipment-500. Detailed Implementation

[0029] To enable those skilled in the art to better understand the present application, the technical solution of the present application will be clearly and thoroughly described below with reference to the accompanying drawings. Obviously, the embodiments described in this application are only a part of the embodiments, and not all of the embodiments. Unless otherwise specified, the different embodiments and features described below can be combined with each other.

[0030] Figure 1 A schematic diagram of the charging circuit provided in this application is shown.

[0031] like Figure 1 As shown, the charging circuit 100 includes a first AC-DC conversion circuit 10 and a first DC-DC conversion circuit 20. The AC terminal of the first AC-DC conversion circuit 10 is connected to the AC power supply 200, the DC terminal of the first AC-DC conversion circuit 10 is connected to the first terminal of the first DC-DC conversion circuit 20, and the second terminal of the first DC-DC conversion circuit 20 is connected to the battery module 300.

[0032] When the battery module 300 requires trickle charging, the AC power supply 200 can charge the battery module 300 through the first AC-DC converter circuit 10 and the first DC-DC converter circuit 20. During this process, the first AC-DC converter circuit 10 converts the AC voltage output from the AC power supply 200 into a DC voltage and supplies it to the first DC-DC converter circuit 20. The first DC-DC converter circuit 20 can continuously and over a wide range adjust the voltage and current, thereby reducing the charging current to meet the low-current charging requirements of the battery module 300. Therefore, the charging circuit 100, based on the first AC-DC converter circuit 10 and the first DC-DC converter circuit 20, can perform trickle charging for the battery module 300.

[0033] In this application, the AC power source 200 may include, for example, an AC generator or an electrical grid.

[0034] The battery module 300 consists of multiple battery cells. The types of battery cells can include traditional batteries such as lithium iron phosphate batteries and ternary lithium batteries, as well as newer batteries such as sodium-ion batteries. Understandably, different types of battery cells have corresponding voltage specifications.

[0035] For example, for lithium iron phosphate batteries, the typical platform voltage is 3.2V, the operating voltage range is 2.5V~3.65V, the discharge cutoff voltage is around 2.5V or even as low as 2.0V, and the required charging voltage range is 0.63~1.14 times the platform voltage.

[0036] For ternary lithium batteries, the typical platform voltage is 3.7V or 3.6V, the operating voltage range is 2.5V~4.2V, the discharge cutoff voltage is around 3.0V or even as low as 2.5V, and the required charging voltage range is 0.66~1.11 times the platform voltage.

[0037] For sodium-ion batteries, the typical plateau voltage is 3.2V, the operating voltage range is 2.0V~4.0V, the discharge cutoff voltage is around 2.0V or even as low as 1.8V, and the required charging voltage range is 0.0~1.33 times the plateau voltage.

[0038] The operating voltage range of the entire battery module 300 depends on the cell type and the number of cells connected in series. Taking lithium iron phosphate cells as an example, the operating voltage range of 4 cells connected in series is 10V~14.6V, the operating voltage range of 8 cells connected in series is 20V~29.2V, the operating voltage range of 10 cells connected in series is 25V~36.5V, and the operating voltage range of 12 cells connected in series is 30V~43.8V.

[0039] In this application, the first AC-DC converter circuit 10 includes an isolated AC-DC converter circuit. For example, the first AC-DC converter circuit 10 may include a flyback AC-DC converter circuit, a forward AC-DC converter circuit, a full-bridge AC-DC converter, or a half-bridge AC-DC converter. In practical applications, the implementation method of the first AC-DC converter circuit 10 can be flexibly selected according to the actual situation.

[0040] Understandably, the first AC-DC converter circuit 10 adopts an isolated AC-DC converter circuit, which can realize the AC to DC conversion function and also realize electrical isolation between the DC end and the AC end.

[0041] The first DC-DC converter circuit 20 includes a bidirectional DC-DC converter circuit. For example, the first DC-DC converter circuit may include a non-isolated DC-DC converter circuit, which includes, but is not limited to, a BUCK (buck) circuit, a BOOST (boost) circuit, or a BUCK-BOOST (buck-boost) circuit. Alternatively, the first DC-DC converter circuit may also include an isolated DC-DC converter circuit.

[0042] In one specific implementation, the first DC-DC converter circuit 20 is as follows: Figure 2 The circuit shown in Figure (a) functions as a BOOST circuit when the first terminal of the first DC-DC converter 20 is used as the input terminal and the second terminal is used as the output terminal. When the second terminal of the first DC-DC converter 20 is used as the input terminal and the first terminal is used as the output terminal, the first DC-DC converter 20 functions as a BUCK circuit.

[0043] In another implementation, the first DC-DC converter circuit 20 is as follows: Figure 2 The circuit shown in Figure (b) functions as a BUCK circuit when the first terminal of the first DC-DC converter 20 is used as the input terminal and the second terminal is used as the output terminal. When the second terminal of the first DC-DC converter 20 is used as the input terminal and the first terminal is used as the output terminal, the first DC-DC converter 20 functions as a BOOST circuit.

[0044] In yet another implementation, the first DC-DC converter circuit 20 is as follows: Figure 2 In the BUCK-BOOST circuit shown in Figure (c), whether the first terminal of the first DC-DC converter 20 is used as the input terminal or the second terminal is used as the input terminal, the first DC-DC converter 20 can be selected as the BOOST circuit according to the boost requirement or as the BUCK circuit according to the buck requirement.

[0045] Specifically, assuming the first AC-DC converter circuit 10 outputs a 24V DC voltage, and the battery module 300 consists of 10 lithium iron phosphate batteries connected in series, the operating voltage of the battery module 300 (25V~36.5V) is always greater than 24V. Therefore, the first DC-DC converter circuit 20 can be adopted as follows: Figure 2 The circuit shown in Figure (a) or (c) is used to boost 24V to the range of 25V to 36.5V.

[0046] In another example, assuming the first AC-DC converter outputs a 24V DC voltage, and the battery module 300 consists of four lithium iron phosphate batteries connected in series, since the operating voltage of the battery module 300 (10V~14.6V) is always less than 24V, the first DC-DC converter 20 can be configured as follows: Figure 2 The circuit shown in Figure (b) or (c) is used to reduce the voltage from 24V to the range of 10V to 14.6V.

[0047] In another example, assuming the first AC-DC converter outputs a 24V DC voltage, and the battery module 300 consists of eight lithium iron phosphate batteries connected in series, the first DC-DC converter 20 can be adopted as follows: Figure 2 The circuit shown in Figure (c) of the diagram, where the first DC-DC converter circuit 20 reduces the 24V to the 20V~24V range when the operating voltage range of the battery module 300 is 20V~24V. When the required charging voltage range of the battery module 300 is 24V~29.2V, the first DC-DC converter circuit 20 increases the 24V to the 24V~29.2V range.

[0048] Understandably, the first DC-DC converter circuit 20 adopts a non-isolated DC-DC converter circuit, which can realize the DC-DC function and also has better low voltage and low current output capability.

[0049] In related technologies, the charging circuit 100 typically uses an isolated DC-DC converter to output charging voltage and charging current to the battery module 300. However, the voltage gain range of the isolated DC-DC converter is limited. For example, under ideal operating conditions without considering component errors, the voltage gain range of an LLC resonant converter is generally limited to 0.7 to 1.3 times, significantly smaller than the charging voltage range of the battery module 300. Therefore, the charging circuit 100 in related technologies cannot adequately meet the low-voltage trickle charging requirements of the battery module 300, leading to excessive current during charging. This can cause safety risks such as metal deposition and dendrite formation in the battery module 200, and prolonged charging may even lead to battery fire or explosion risks.

[0050] Furthermore, isolated DC-DC converter circuits struggle to achieve soft switching under light load and low voltage output. The current generated under light load is a peak pulse current with a wavy shape, making low-voltage trickle charging impossible. The inability to achieve soft switching leads to increased switching losses, reduced conversion efficiency, accelerated device aging, decreased reliability, increased electromagnetic interference, and even shoot-through damage to the switching transistor, causing circuit failure. Peak pulse currents can accelerate cell aging, capacity decay, cell expansion or rupture, and even thermal runaway, causing uneven electrode surface deposition, dendrite formation, and internal short circuits.

[0051] Compared to isolated DC-DC converters, non-isolated DC-DC converters offer a wider voltage gain range at low output voltages, for example, 0 to 2 times. Therefore, the voltage regulation range of non-isolated DC-DC converters is wider than that of isolated DC-DC converters, enabling wide-range and continuous adjustment of DC voltage and current to achieve lower charging voltage and current. Consequently, non-isolated DC-DC converters are well-suited for the low-voltage trickle charging requirements of battery module 300, ensuring the implementation of the low-voltage trickle charging function. Furthermore, they avoid the safety risks associated with the difficulty of balancing soft switching and low-voltage trickle output in isolated DC-DC converters.

[0052] Optionally or additionally, such as Figure 3 As shown, the charging circuit 100 may further include a control circuit 30, with the first DC-DC converter circuit 20 and the first AC-DC converter circuit 10 electrically connected to the control circuit 30. The control circuit 30 may be a circuit or chip with control functions, such as a microcontroller unit (MCU). In a specific implementation, the control circuit 30 may be an MCU in a battery management system (BMS).

[0053] The control circuit 30 can be used to monitor the operating status of the battery module 300. When the battery module 300 meets the first charging condition, it controls the first DC-DC converter circuit 20 and the first AC-DC converter circuit 10 to work so that the AC power supply 200 charges the battery module 300 through the first AC-DC converter circuit 10 and the first DC-DC converter circuit 20.

[0054] In this application, the first charging condition includes at least one of the following: the voltage of the battery cell in the battery module 300 is less than a voltage threshold; the temperature of the battery cell in the battery module 300 is less than a temperature threshold.

[0055] It is understandable that if the voltage of the battery cell in battery module 300 is lower than the voltage threshold, it indicates that battery module 300 is at a low voltage. Similarly, if the temperature of the battery cell is lower than the temperature threshold, it indicates that battery module 300 is at a low temperature. In scenarios where battery module 300 is at a low voltage or low temperature, to prevent metal deposition and dendrite formation, which could lead to internal short circuits and other safety issues, battery module 300 needs to be pre-charged with a small current. Therefore, the first charging condition indicates that battery module 300 has a trickle charging requirement at this time.

[0056] In the first charging condition, the voltage of the cells in the battery module 300 can refer to the voltage of a single cell in the battery module 300. In a specific implementation, the control circuit 30 can acquire the voltage of each cell, and the lowest voltage among the multiple cell voltages can be used to represent the voltage of the cells in the battery module 300.

[0057] The voltage threshold can be set according to the actual cell type used in the battery module 300, and is not limited here. For example, the voltage threshold can be the discharge cutoff voltage of a single cell in the battery module 300. Alternatively, the voltage threshold can be a voltage value close to the discharge cutoff voltage of a single cell, that is, a voltage value slightly larger than the discharge cutoff voltage of a single cell, or a voltage value smaller than the discharge cutoff voltage of a single cell.

[0058] Taking a sodium-ion battery voltage threshold of 2.0V as an example, when the control circuit 30 detects that the voltage of a single sodium-ion battery in the battery module 300 is less than or equal to 2.0V, it determines that the battery module 300 meets the first charging condition. Therefore, the control circuit 30 controls the first AC-DC converter circuit 10 and the first DC-DC converter circuit 20 to work to charge the battery module 300.

[0059] In the first charging condition, the temperature of the cells in the battery module 300 refers to the temperature of an individual cell in the battery module 300. In a specific implementation, the control circuit 30 can measure the cell temperature using temperature sensors. The number of temperature sensors can be set according to actual needs. For example, if the battery module 300 includes 8 cells, then 4 temperature sensors can be set. The lowest cell temperature among the 4 cell temperature data can be used to represent the temperature of the cells in the battery module 300.

[0060] The temperature threshold can be set according to the actual situation. In some examples, the temperature threshold can be 15℃, 10℃, 0℃, -10℃, -20℃, or other temperature values ​​that can characterize a low battery temperature. Taking a temperature threshold of 0℃ as an example, when the control circuit 30 detects that the temperature of a single cell in the battery module 300 is close to or equal to 0℃, it determines that the battery module 300 meets the first charging condition. Therefore, the control circuit 30 controls the first AC-DC converter circuit 10 and the first DC-DC converter circuit 20 to work to charge the battery module 300.

[0061] It should be understood that in practical applications, the battery module 300 may also have other situations that require trickle charging. In these situations, the AC power supply 200 can charge the battery module 300 through the first DC-DC conversion circuit 20 and the first AC-DC conversion circuit 10.

[0062] In this application, when the battery module 300 meets the first charging condition, the battery module 300 enters trickle charging mode. Therefore, when the battery module 300 meets the first charging condition, the first AC-DC converter circuit 10 and the first DC-DC converter circuit 20 output a constant small current (e.g., 0.01C, 0.02C, etc.) to charge the battery module 300.

[0063] In one or more embodiments, when the battery module 300 meets the first charging condition, the first DC-DC converter circuit 20 can operate in a corresponding working mode according to the voltage conditions of the battery module 300 and the first AC-DC converter circuit 10.

[0064] In one example, when the battery module 300 meets the first charging condition and its voltage is higher than the output voltage of the first AC-DC converter circuit 10, the first DC-DC converter circuit 20 operates in boost mode, causing the charging voltage output from the second terminal of the first DC-DC converter circuit 20 to be higher than the output voltage of the first AC-DC converter circuit 10. Specifically, assuming the first AC-DC converter circuit 10 outputs a 24V voltage and the battery module 300 has a 36V voltage, the first DC-DC converter circuit 20 will operate in boost mode, boosting the 24V voltage to 36V or slightly higher and outputting it to the battery module 300.

[0065] In another example, when the battery module 300 meets the first charging condition and its voltage is lower than the output voltage of the first AC-DC converter circuit 10, the first DC-DC converter circuit 20 operates in buck mode, causing the voltage output at the second terminal of the first DC-DC converter circuit 20 to be lower than the output voltage of the first AC-DC converter circuit 10. Specifically, assuming the first AC-DC converter circuit 10 outputs a 24V voltage and the battery module 300 has a 12V voltage, the first DC-DC converter circuit 20 will operate in buck mode, reducing the 24V voltage to 12V or slightly higher and outputting it to the battery module 300.

[0066] This design allows the charging voltage output from the second terminal of the first DC-DC converter circuit 20 to be adapted to the current voltage of the battery module 300. This avoids situations where the charging voltage is lower than the current voltage of the battery module 300, resulting in the inability to charge the battery module 300, or where the charging current is much greater than the trickle charging current that the battery module 300 can currently withstand, leading to safety risks such as metal deposition and dendrite formation in the battery module. This design is beneficial to charging safety.

[0067] When the battery module 300 meets the first charging condition, the first DC-DC converter circuit 20 can operate in a constant current state, that is, the first DC-DC converter circuit 20 outputs a constant current to charge the battery module 300 until the battery module 300 meets the normal charging condition, such as the lowest voltage of the battery cell in the battery module 300 being greater than the discharge cutoff voltage of 2.5V, and the lowest temperature of the battery cell being within the normal charging temperature range (e.g., 0℃~45℃).

[0068] In some optional examples, the charging circuit 100 may also include a current sampling circuit connected to the first DC-DC converter circuit 20 and the control circuit 30.

[0069] The current sampling circuit can sample the charging current of the AC power supply 200 charging the battery module 300 through the first AC-DC conversion circuit 10 and the first DC-DC conversion circuit 20. The control circuit 30 can adjust the operation of at least one of the first DC-DC conversion circuit 20 and the first AC-DC conversion circuit 10 based on the charging current sampled by the current sampling circuit, so that the second terminal of the first DC-DC conversion circuit 20 can output a small constant charging current (e.g., a charging rate of 0.01C to 0.1C), thereby realizing trickle charging of the battery module 300.

[0070] The current sampling circuit includes a current sensing element for detecting current. The type of current sensing element is not limited; for example, it may include a shunt resistor, a Hall sensor, or a current transformer (CT). The placement of the current sensing element is not limited, as long as it is electrically connected to the first DC-DC converter circuit 20.

[0071] Taking a shunt resistor R1 as an example where the current sensing element is used. In one example, such as... Figure 3 As shown in Figure (a), the shunt resistor R1 can be placed in the first DC-DC converter circuit 20 and connected in series with the switching transistor Q1 in the first DC-DC converter circuit 20. In another example, as... Figure 3 As shown in Figure (b), the shunt resistor R1 can be placed in the first DC-DC converter circuit 20 and connected in series with the inductor L1 in the first DC-DC converter circuit 20. In another example, as... Figure 3 As shown in Figure (c), the shunt resistor R1 can be placed at the second terminal of the first DC-DC converter circuit 20. Alternatively, the shunt resistor R1 can also be placed at the first terminal of the first DC-DC converter circuit 20. Figure 3 (Not shown in the image). In the example above, the charging current can be calculated based on the voltage across the shunt resistor R1 and the resistance value of the shunt resistor R1.

[0072] Optional or additional, such as Figure 4 As shown, the charging circuit 100 may further include a second AC-DC converter circuit 40 and a second DC-DC converter circuit 50. The AC terminal of the second AC-DC converter circuit 40 is connected to the AC power supply 200, the DC terminal of the second AC-DC converter circuit 40 is connected to the first terminal of the second DC-DC converter circuit 50, and the second terminal of the second DC-DC converter circuit 50 is connected to the battery module 300.

[0073] The second AC-DC converter circuit 40 and the second DC-DC converter circuit 50 are also connected to the control circuit 30. The control circuit 30 can be used to control the second DC-DC converter circuit 50 and the second AC-DC converter circuit 40 to work when the battery module 300 meets the second charging condition, so that the AC power supply 200 charges the battery module 300 through the second AC-DC converter circuit 40 and the second DC-DC converter circuit 50.

[0074] In this application, the second charging condition includes: the voltage of the battery cell in the battery module 300 is greater than a voltage threshold, and the temperature of the battery cell in the battery module 300 is greater than a temperature threshold.

[0075] Specifically, "the voltage of a cell in battery module 300 is greater than the voltage threshold" means that the minimum voltage among all cells in battery module 300 is greater than the voltage threshold; in other words, the voltage of all cells in battery module 300 is greater than the voltage threshold. "The temperature of a cell in battery module 300 is greater than the temperature threshold" means that the lowest temperature among all cells in battery module 300 is greater than the temperature threshold; in other words, the temperature of all cells in battery module 300 is greater than the temperature threshold. Other details regarding cell voltage, cell temperature, voltage threshold, and temperature threshold can be found in the aforementioned description of the first charging condition and will not be repeated here.

[0076] It is understandable that if the voltage of the battery cell in battery module 300 is greater than the voltage threshold and the temperature of the battery cell is greater than the temperature threshold, it indicates that battery module 300 is in a normal state and can therefore be charged normally, i.e., it can be charged using conventional charging methods. Therefore, the second charging condition indicates that battery module 300 has a conventional charging requirement at this time.

[0077] During the power supply process, the second AC-DC conversion circuit 40 can convert the AC voltage output by the AC power supply 200 into DC voltage and supply it to the second DC-DC conversion circuit 50. The second DC-DC conversion circuit 50 can adjust the DC voltage to the normal charging voltage of the battery module 300 to meet the normal charging requirements of the battery module 300.

[0078] In addition, the second DC-DC converter circuit 50 can output a conventional charging current to the battery module 300, which can be in the range of a charging rate of 0.2C to 1C.

[0079] Optionally or additionally, the second AC-DC converter circuit 40 includes a full-bridge PFC circuit, etc.

[0080] The second DC-DC converter circuit 50 includes an isolated DC-DC converter circuit. Preferably, the second DC-DC converter circuit 50 includes a dual active bridge converter circuit, an LLC converter circuit, or a CLLC converter circuit. In practical applications, the implementation method of the second DC-DC converter circuit 50 can be flexibly selected according to the actual situation.

[0081] It is understood that the first terminal of the second DC-DC converter circuit 50 is connected to the high-voltage AC power supply 200 through the second AC-DC converter circuit, and the second terminal of the second DC-DC converter circuit is connected to the low-voltage battery module 300. The use of an isolated DC-DC converter circuit can achieve electrical isolation between the low-voltage side and the high-voltage side, thus meeting safety requirements.

[0082] To address the charging methods of the battery module 300 under low voltage, low temperature, and normal conditions, the charging circuit 100 of this application employs different circuits to supply power to the battery module 300, adapting to the charging requirements of different charging methods. This reduces the risk of lithium plating during battery charging while improving charging efficiency.

[0083] Optionally or additionally, the charging circuit 100 may further include a first drive circuit 80 for driving the second DC-DC converter circuit 50 and a second drive circuit 90 for driving the second AC-DC converter circuit 40. The control circuit 30 can control the operation of the second DC-DC converter circuit 50 and the second AC-DC converter circuit 40 by controlling the first drive circuit 80 and the second drive circuit 90. The first drive circuit 80 may be integrated into the second DC-DC converter circuit 50, and the second drive circuit 90 may be integrated into the second AC-DC converter circuit 40; alternatively, these drive circuits may be provided separately.

[0084] Similarly, the charging circuit 100 may also include a drive circuit (not shown in the figure) for the first DC-DC converter circuit 20 and a drive circuit (not shown in the figure) for the first AC-DC converter circuit 10. The control circuit 30 controls the operation of the first DC-DC converter circuit 20 and the first AC-DC converter circuit 10 by controlling the drive circuit.

[0085] Optionally or additionally, the charging circuit 100 may also include a first unidirectional conductor D1, a second unidirectional conductor D2, a voltage conversion circuit 60, and a third DC-DC converter circuit 70.

[0086] The input terminal of voltage conversion circuit 60, the first terminal of third DC-DC converter circuit 70, the first terminal of first DC-DC converter, and the DC terminal of first AC-DC converter circuit 10 are connected to the first node N1. The output terminal of voltage conversion circuit 60 is connected to control circuit 30, and the second terminal of third DC-DC converter circuit 70 is connected to first drive circuit 80 and second drive circuit 90. First unidirectional conductor D1 is disposed between the DC terminal of first AC-DC converter circuit 10 and first node N1. The first terminal of first unidirectional conductor D1 is connected to the DC terminal of first AC-DC converter circuit 10, and the second terminal of first unidirectional conductor D1 is connected to first node N1. The first terminal of second unidirectional conductor D2 is connected to first node N1, and the second terminal of second unidirectional conductor D2 is connected to the input terminal of voltage conversion circuit 60 and the first terminal of third DC-DC converter circuit 70.

[0087] Based on this circuit design, the control circuit 30 can control the first DC-DC converter circuit 20 to operate when the battery module 300 meets the discharge conditions, so that the battery module 300 outputs electrical energy to the first node N1 through the first DC-DC converter circuit 20. Furthermore, both the voltage conversion circuit 60 and the third DC-DC converter circuit 70 can receive the electrical energy output from the first DC-DC converter circuit. The voltage conversion circuit 60 further supplies power to the control circuit 30, and the third DC-DC converter circuit 70 further supplies power to the first drive circuit 80 and the second drive circuit 90.

[0088] Since the first DC-DC converter circuit is reused to power the voltage conversion circuit and the third DC-DC converter circuit, the charging circuit 100 of this application can achieve both charging the battery module 300 through the first DC-DC converter circuit and powering the voltage conversion circuit and the third DC-DC converter circuit through the first DC-DC converter circuit without increasing hardware costs.

[0089] In this application, discharge conditions are used to characterize the discharge capability of the battery module 300. Specifically, the discharge conditions include: the lowest voltage of the battery cell in the battery module 300 is greater than the discharge cutoff voltage of the battery cell, and the lowest temperature of the battery cell in the battery module 300 is within the discharge temperature range of the battery cell. In some specific examples, the discharge temperature range of the battery cell is, for example, -20~60℃, and this application does not specifically limit the discharge temperature range of the battery cell.

[0090] During the process of the battery module 300 supplying power to the voltage conversion circuit 60 and the third DC-DC conversion circuit 70, the control circuit 30 controls the first AC-DC conversion circuit 10 to stop working in order to reduce power consumption.

[0091] The first one-way conductor D1 limits the current flow from the DC terminal of the first AC-DC converter 10 to the first node N1, preventing current from flowing back into the first AC-DC converter 10. The second one-way conductor D2 limits the current flow from the first node N1 to the voltage conversion circuit 60 and the third DC-DC converter 70, preventing current from flowing in the opposite direction.

[0092] In this application, both the first unidirectional conductor D1 and the second unidirectional conductor D2 can be devices with unidirectional conduction characteristics, such as unidirectional diodes or other unidirectional semiconductor devices. For ease of description, Figure 5 The example uses diodes as examples, where the anode of the diode is the first terminal of the unidirectional conductor and the cathode of the diode is the second terminal of the unidirectional conductor.

[0093] The voltage conversion circuit 60 may include a non-isolated DC-DC converter or a low-dropout linear regulator. Both the non-isolated DC-DC converter and the low-dropout linear regulator can convert the input DC voltage into a stable DC voltage to power the control circuit 30.

[0094] The third DC-DC converter circuit 70 includes isolated DC-DC converter circuits, such as flyback circuits and forward circuits. The third DC-DC converter circuit 70 can perform DC-DC conversion and can also electrically isolate the first and second terminals of the third DC-DC converter circuit 70 to prevent noise interference from the first drive circuit 80 and the second drive circuit 90 from being introduced into other circuits connected to the first terminal of the third DC-DC converter circuit 70.

[0095] In some implementations, when the battery module 300 is not discharged, the first AC-DC converter circuit 10 can be connected to the AC power supply 200 to supply power to the control circuit 30 and the third DC-DC converter circuit 70. Therefore, the first AC-DC converter circuit 10 can not only supply power to the control circuit 30 and the third DC-DC converter circuit 70, but also charge the battery module 300 in low voltage or low temperature scenarios through the first AC-DC converter circuit 10 and the first DC-DC converter circuit 20, realizing different functions of the first AC-DC converter, thereby reducing hardware costs.

[0096] The following is combined with Figure 5 and Figure 6 ,right Figure 4 The working principle of the charging circuit 100 will be explained in general.

[0097] For a 300-watt battery module charging scenario: When the voltage of a single cell in the battery module 300 is detected to be less than the voltage threshold, or the temperature of a single cell in the battery module 300 is lower than the temperature threshold, it indicates that the battery module 300 meets the first charging condition. The control circuit 30 can then control the first DC-DC converter circuit 20 and the first AC-DC converter circuit 10 to start working, while the second DC-DC converter circuit 50 and the second AC-DC converter circuit 40 do not work.

[0098] At this time, as Figure 5 As shown by the dashed line with arrows in Figure (a), the AC power supply 200 can provide a constant, small charging current to the battery module 300 through the first AC-DC conversion circuit 10 and the first DC-DC conversion circuit 20, so that the battery module 300 can perform trickle charging.

[0099] When the voltage of each cell in the battery module 300 is detected to be higher than the voltage threshold and the cell temperature of each cell in the battery module 300 is detected to be higher than the temperature threshold, it indicates that the battery module 300 meets the second charging condition, and the control circuit 30 can control the second DC-DC converter circuit 50 and the second AC-DC converter circuit 40 to start working.

[0100] At this time, as Figure 5 As shown by the dashed arrow in Figure (b), the AC power supply 200 can provide the battery module 300 with conventional charging voltage and charging current through the second AC-DC conversion circuit 40 and the second DC-DC conversion circuit 50, enabling the battery module 300 to charge normally. This can improve the charging efficiency of the battery module 300 and quickly charge it to a fully charged state.

[0101] Understandably, if the cell temperature of battery module 300 remains below the temperature threshold, it can continuously pass... Figure 5 (a) The charging path described is for charging the battery module 300. If the battery module 300 initially meets the second charging condition, it can be directly charged via... Figure 5 (b) The charging path described is for charging battery module 300.

[0102] For a 300 discharge scenario for the battery module: When the lowest voltage of the battery cell in the battery module 300 is detected to be greater than the discharge cutoff voltage, and the cell temperature of the battery cell in the battery module 300 is within the discharge temperature range, it indicates that the battery module 300 meets the discharge conditions.

[0103] At this time, as Figure 6As shown by the dashed arrow in Figure (a), the control circuit 30 can control the first DC-DC converter circuit 20 to operate, so that the battery module 300 is powered by the first DC-DC converter circuit 20, the voltage conversion circuit 60, and the third DC-DC converter circuit 70, respectively, for the control circuit 30, the first drive circuit 80, and the second drive circuit 90. To reduce power consumption, the control circuit 30 can simultaneously disable the first AC-DC converter circuit 10.

[0104] It should be understood that when the voltage of the battery cell in the battery module 300 is detected to be low (but still higher than the discharge cutoff voltage), and the first AC-DC conversion circuit 10 is connected to the AC power supply 200, the control circuit 30 can control the first AC-DC conversion circuit 10 to start working and the first DC-DC conversion circuit 20 to stop working.

[0105] Therefore, as Figure 6 As shown by the dashed line with arrows in Figure (b), the AC power supply 200 can be powered by the first AC-DC conversion circuit 10, the voltage conversion circuit 60, and the third DC-DC conversion circuit 70, respectively, for the control circuit 30, the first drive circuit 80, and the second drive circuit 90.

[0106] This application also provides a battery device.

[0107] Please see Figure 7 The battery device 400 includes a battery module 300 and the aforementioned charging circuit 100.

[0108] The number of battery cells in the battery module 300 can be set according to actual needs. In some examples, the battery module 300 includes 4, 8, 14, or 16 battery cells connected in series. The charging circuit 100 is disposed on a printed circuit board, and the battery device 400 is formed by assembling the printed circuit board, the battery module 300, and structural components (such as housing, aviation connectors, etc.).

[0109] When the battery device 400 is running, the charging circuit 100 can perform trickle charging on the battery module 300 according to the first charging condition requirement of the battery module 300, or normally charge the battery module 300 according to the second charging condition requirement of the battery module 300, or the battery module 300 can also be discharged through the first DC-DC conversion circuit 20 in the charging circuit 100.

[0110] Understandably, other details regarding the battery module 300 and charging circuit 100 can be found in the preceding descriptions and will not be repeated here.

[0111] This application also provides a power supply device.

[0112] Please see Figure 8The power supply device 500 includes the aforementioned battery device 400. Details of the battery device 400 can be found in [reference needed]. Figure 7 The relevant descriptions in the document will not be repeated here.

[0113] The type of power supply equipment 500 is not limited, and includes, for example, portable power banks, residential energy storage devices, commercial and industrial energy storage devices, communication energy storage devices, and uninterruptible power supplies (UPS), etc., which are not listed here. Portable power banks can include low-power power banks (e.g., with capacities of 1kWh, 2kWh, etc.), which can be used to power low-power loads such as mobile phones, computers, and portable refrigerators. Portable power supply equipment can also include outdoor power banks, which can be used to power high-power loads such as electric vehicles.

[0114] This application also provides a power supply method. This power supply method can be applied to the above-described charging circuit 100, battery device 400, or power supply device 500, and can be executed by the control circuit 30.

[0115] Specifically, power supply methods may include: In response to the battery module meeting a first charging condition, the first AC-DC conversion circuit and the first DC-DC conversion circuit are controlled to operate, so that the AC power supply charges the battery module through the first AC-DC conversion circuit and the first DC-DC conversion circuit; wherein, the first charging condition includes: the voltage of the battery cell in the battery module is less than a voltage threshold, and / or, the temperature of the battery cell is lower than a temperature threshold.

[0116] In one example, the process of controlling the operation of the first DC-DC converter circuit in a low-temperature charging scenario may include: In response to the battery module meeting the first charging condition and the battery module voltage being higher than the output voltage of the first AC-DC converter circuit, the first DC-DC converter circuit is controlled to operate in boost mode, so that the voltage output at the second terminal of the first DC-DC converter circuit is higher than the output voltage of the first AC-DC converter circuit.

[0117] Alternatively, in response to the battery module meeting the first charging condition and the battery module voltage being lower than the output voltage of the first AC-DC converter circuit, the first DC-DC converter circuit is controlled to operate in buck mode, so that the voltage output at the second terminal of the first DC-DC converter circuit is lower than the output voltage of the first AC-DC converter circuit.

[0118] In other words, the first DC-DC converter circuit can operate in a suitable working mode according to the voltage conditions of the battery module and the first AC-DC converter circuit, so as to output a charging voltage that matches the current voltage condition of the battery module, which helps to improve charging safety.

[0119] In another example, when the battery module is in a low-voltage charging scenario, i.e., when the minimum voltage value of the battery cell in the battery module is less than the voltage threshold, the process of controlling the operation of the first DC-DC converter circuit may also include: In response to the battery module meeting the first charging condition, the second terminal of the first DC-DC converter circuit is controlled to output a constant charging current.

[0120] In this way, the AC power supply can perform low-voltage trickle charging of the battery module through the first AC-DC conversion circuit and the first DC-DC conversion circuit.

[0121] Optionally or additionally, the power supply method may also include: In response to the battery module meeting the second charging condition, the second AC-DC conversion circuit and the second DC-DC conversion circuit are controlled to operate, so that the AC power supply charges the battery module through the second AC-DC conversion circuit and the second DC-DC conversion circuit; wherein, the second charging condition includes: the voltage of the battery cell in the battery module is greater than the voltage threshold, and the temperature of the battery cell is greater than the temperature threshold.

[0122] In other words, when the battery module is neither at low voltage nor low temperature, the AC power supply charges the battery module normally through the second AC-DC conversion circuit and the second DC-DC conversion circuit.

[0123] Therefore, the power supply method of this application can not only realize low-voltage trickle charging of the battery module, but also realize regular charging of the battery module, so that the different charging needs of the battery module can be met.

[0124] Optionally or additionally, the power supply method may also include: In response to the battery module meeting the discharge conditions, the first DC-DC converter circuit is controlled to operate, and the battery module supplies power to the voltage conversion circuit and the third DC-DC converter circuit through the first DC-DC converter circuit; wherein, the discharge conditions include: the minimum voltage of the battery cell in the battery module is greater than the discharge cutoff voltage of the battery cell, and the temperature of the battery cell is within the discharge temperature range of the battery cell.

[0125] In other words, in scenarios where the battery module has the ability to discharge, the battery module can supply power to the voltage conversion circuit and the third DC-DC conversion circuit through the first DC-DC conversion circuit.

[0126] Optionally or additionally, the power supply method may also include: In response to the battery module not meeting the discharge conditions and the first AC-DC conversion circuit being connected to an AC power source, the first AC-DC conversion circuit is controlled to supply power to the voltage conversion circuit and the third DC-DC conversion circuit.

[0127] In other words, in scenarios where the battery module does not have the ability to discharge, AC power is supplied to the voltage conversion circuit and the third DC-DC conversion circuit through the first AC-DC conversion circuit.

[0128] Understandably, after the voltage conversion circuit and the third DC-DC converter circuit are powered, they can supply power to other connected circuits. For example, the voltage conversion circuit can supply power to the control circuit, and the third DC-DC converter circuit can supply power to the drive circuit of the second DC-DC converter circuit and the drive circuit of the second AC-DC converter circuit.

[0129] Therefore, the power supply method of this application can not only charge the battery module, but also supply power to the battery module. In one example, in a battery module discharge scenario, the process of controlling the operation of the first DC-DC converter circuit may include: In response to the battery module meeting the discharge conditions and the battery module voltage being higher than the output voltage of the first AC-DC converter circuit, the first terminal of the first DC-DC converter circuit is controlled to output a discharge voltage, which is lower than the battery module voltage.

[0130] Alternatively, in response to the battery module meeting the discharge conditions and the battery module voltage being lower than the output voltage of the first AC-DC converter circuit, the first terminal of the first DC-DC converter circuit is controlled to output a discharge voltage, which is higher than the battery module voltage.

[0131] In other words, the first DC-DC converter circuit can operate in a working mode that matches the voltage of the battery module and the first AC-DC converter circuit to output a suitable discharge voltage, which helps to improve discharge safety.

[0132] It should be understood that the method embodiments can also refer to the relevant descriptions in the foregoing charging circuit embodiments, which will not be repeated here.

[0133] For the sake of simplicity, the power supply method is described as a series of actions in the method embodiments. However, those skilled in the art should know that the method of this application is not limited to the described order of actions, because according to this application, some steps can be performed in other orders or simultaneously.

[0134] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this application without departing from the spirit and scope of the technical solutions of this application.

Claims

1. A charging circuit, characterized in that, The charging circuit includes: A first AC-DC converter circuit, wherein the AC terminal of the first AC-DC converter circuit is configured to be connected to an AC power source; A first DC-DC converter circuit, wherein the DC terminal of the first AC-DC converter circuit is connected to the first terminal of the first DC-DC converter circuit, and the second terminal of the first DC-DC converter circuit is configured to be connected to the battery module. The charging circuit is configured such that, in response to the battery module meeting a first charging condition, the AC power supply charges the battery module through the first AC-DC conversion circuit and the first DC-DC conversion circuit. The first charging condition includes: the voltage of the battery cell in the battery module is less than a voltage threshold, and / or the temperature of the battery cell is lower than a temperature threshold.

2. The charging circuit according to claim 1, characterized in that, The charging circuit includes: A second AC-DC converter circuit, wherein the AC terminal of the second AC-DC converter circuit is configured to be connected to the AC power supply; A second DC-DC converter circuit, wherein the DC terminal of the second AC-DC converter circuit is connected to the first terminal of the second DC-DC converter circuit, and the second terminal of the second DC-DC converter circuit is configured to be connected to the battery module; The charging circuit is configured such that, in response to the battery module meeting the second charging condition, the AC power supply charges the battery module through the second AC-DC conversion circuit and the second DC-DC conversion circuit. The second charging condition includes: the voltage of the battery cell in the battery module is greater than the voltage threshold, and the temperature of the battery cell is greater than the temperature threshold.

3. The charging circuit according to claim 2, characterized in that, The first AC-DC converter circuit is an isolated AC-DC converter circuit, and the second AC-DC converter circuit includes a full-bridge PFC circuit. The first DC-DC converter circuit is a bidirectional DC-DC converter circuit. Preferably, the first DC-DC converter circuit includes a non-isolated DC-DC converter circuit. The second DC-DC converter circuit is an isolated DC-DC converter circuit. Preferably, the second DC-DC converter circuit includes a dual active bridge converter circuit, an LLC converter circuit, or a CLLC converter circuit.

4. The charging circuit according to claim 2 or 3, characterized in that, The charging circuit includes: The control circuit includes the first AC-DC converter circuit, the second AC-DC converter circuit, the first DC-DC converter circuit, and the second DC-DC converter circuit, which are respectively connected to the control circuit. A current sampling circuit is connected to the first DC-DC converter circuit and the control circuit. The current sampling circuit is configured to sample the charging current of the AC power supply charging the battery module through the first AC-DC converter circuit and the first DC-DC converter circuit.

5. The charging circuit according to any one of claims 1-4, characterized in that, The charging circuit includes: a first unidirectional conductor, a second unidirectional conductor, a voltage conversion circuit, and a third DC-DC converter circuit; The input terminal of the voltage conversion circuit, the first terminal of the third DC-DC conversion circuit, the first terminal of the first DC-DC circuit, and the DC terminal of the first AC-DC conversion circuit are connected to the first node. The first unidirectional conductor is disposed between the DC terminal of the first AC-DC converter circuit and the first node. The first unidirectional conductor is used to limit the current from the DC terminal of the first AC-DC converter circuit to the first node. The first end of the second unidirectional conductor is connected to the first node, and the second end of the second unidirectional conductor is connected to the input terminal of the voltage conversion circuit and the first terminal of the third DC-DC conversion circuit. The second unidirectional conductor is used to limit the current flow from the first node to the voltage conversion circuit and the third DC-DC conversion circuit.

6. A battery device, characterized in that, It includes a battery module and a charging circuit as described in any one of claims 1-5.

7. A power supply device, characterized in that, Includes the battery device as described in claim 6.

8. A power supply method, characterized in that, The method, applied to the charging circuit according to any one of claims 1-5, comprises: In response to the battery module meeting the first charging condition, the first AC-DC conversion circuit and the first DC-DC conversion circuit are controlled to operate, so that the AC power supply charges the battery module through the first AC-DC conversion circuit and the first DC-DC conversion circuit.

9. The power supply method as described in claim 8, characterized in that, The method further includes: In response to the battery module meeting the second charging condition, the second AC-DC conversion circuit and the second DC-DC conversion circuit are controlled to operate, so that the AC power supply charges the battery module through the second AC-DC conversion circuit and the second DC-DC conversion circuit.

10. The power supply method as described in claim 8 or 9, characterized in that, The method further includes: In response to the battery module meeting the first charging condition, the second terminal of the first DC-DC converter circuit is controlled to output a constant charging current.

11. The power supply method according to any one of claims 8-10, characterized in that, The method further includes: In response to the battery module meeting the first charging condition and the voltage of the battery module being higher than the output voltage of the first AC-DC converter circuit, the first DC-DC converter circuit is controlled to operate in boost mode. Alternatively, in response to the battery module meeting the first charging condition and the voltage of the battery module being lower than the output voltage of the first AC-DC converter circuit, the first DC-DC converter circuit is controlled to operate in buck mode.

12. The power supply method according to any one of claims 8-11, characterized in that, The method further includes: In response to the battery module meeting the discharge conditions, the first DC-DC converter circuit is controlled to operate, and the battery module supplies power to the voltage conversion circuit and the third DC-DC converter circuit through the first DC-DC converter circuit; The discharge conditions include: the lowest voltage of the cell in the battery module is greater than the discharge cutoff voltage of the cell, and the temperature of the cell is within the discharge temperature range of the cell.

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