Power supply circuit and power supply device

Abstract

The utility model discloses a power supply circuit and power supply equipment. The power supply circuit comprises a first battery module and at least one second battery module, the first battery module comprises a first battery, a first charging and discharging switch unit and a first parallel operation end, and the first battery is connected with the first charging and discharging switch unit; the second battery module comprises a second battery, a second charging and discharging switch unit, a direct-current conversion circuit and a second parallel operation end, the second battery is connected with the second charging and discharging switch unit and the direct-current conversion circuit, and the second charging and discharging switch unit is connected with the direct-current conversion circuit in parallel; wherein the first battery module and the second battery module are connected through the first parallel operation end and the second parallel operation end. Based on the mode, the cost of the power supply circuit is reduced under the condition that the power supply capability of the power supply circuit is not influenced.

Description

Technical Field

[0001] This application relates to the field of power supply technology, and in particular to power supply circuits and power supply equipment. Background Technology

[0002] In existing technologies, multiple battery packs are typically connected in parallel to charge and discharge simultaneously, creating a power circuit capable of providing a large amount of power to supply power to the corresponding devices.

[0003] The drawback of existing technology is that, due to the design of the components or circuits within the battery pack, existing power circuits composed of multiple battery packs in parallel are usually large in size and weight, which in turn leads to excessively high costs. Utility Model Content

[0004] The main technical problem addressed in this application is how to reduce the cost of a power supply circuit without affecting its power supply capability.

[0005] To solve the above-mentioned technical problems, the first technical solution adopted in this application is: a power supply circuit, including a first battery module and at least one second battery module; the first battery module includes a first battery and a first charge / discharge switch unit, one end of the first battery is connected to one end of the first charge / discharge switch unit, and the other end of the first charge / discharge switch unit and the other end of the first battery together serve as a first parallel terminal; the second battery module includes a second battery, a second charge / discharge switch unit and a DC-DC conversion circuit, one end of the second battery is connected to one end of the second charge / discharge switch unit and one end of the DC-DC conversion circuit respectively, the other end of the second charge / discharge switch unit is connected to the other end of the DC-DC conversion circuit, and the other end of the second charge / discharge switch unit and the other end of the second battery together serve as a second parallel terminal; the first parallel terminal is connected to the second parallel terminal to connect the first battery module and the second battery module in parallel.

[0006] The DC-DC conversion circuit includes a first switch, a second switch, a third switch, a fourth switch, and an inductor. One end of the first switch serves as one end of the DC-DC conversion circuit, and the other end of the first switch is connected to one end of the second switch and one end of the inductor. The other end of the inductor is connected to one end of the third switch and one end of the fourth switch. The other ends of the second and fourth switches are both grounded, and the other end of the third switch serves as the other end of the DC-DC conversion circuit.

[0007] The second battery module also includes a first control unit, which is connected to the control terminals of the first switching transistor, the second switching transistor, the third switching transistor, the fourth switching transistor, and the second charge / discharge switch unit.

[0008] The second battery module also includes a first fuse, which is connected to one end of the second battery and one end of the DC-DC conversion circuit.

[0009] The first battery module also includes a second fuse, a pre-charge and discharge switch unit, and a current-limiting resistor. The second fuse is connected to one end of the DC-DC conversion circuit and one end of the pre-charge and discharge switch unit. The other end of the pre-charge and discharge switch unit is connected to the other end of the DC-DC conversion circuit. The other end of the current-limiting resistor and the other end of the first battery together serve as the first parallel terminal.

[0010] The second battery module further includes at least one of a first voltage detection unit, a second voltage detection unit, and a battery current detection unit; the detection terminal of the first voltage detection unit is connected to one end of the second battery, and the output terminal of the first voltage detection unit is connected to the first control unit; or, the detection terminal of the second voltage detection unit is connected to the other end of the second charge / discharge switch unit, and the output terminal of the second voltage detection unit is connected to the first control unit; or, the first detection terminal of the battery current detection unit is connected to one end of the second battery, the second detection terminal of the battery current detection unit is connected to the other end of the second battery, and the output terminal of the battery current detection unit is connected to the first control unit.

[0011] The first voltage detection unit includes a fifth switch, a sixth switch, and a first diode. The control terminal of the fifth switch is connected to the first control unit, the first terminal of the fifth switch is connected to the control terminal of the sixth switch, the second terminal of the fifth switch is grounded, the first terminal of the sixth switch is the detection terminal of the first voltage detection unit, the second terminal of the sixth switch is connected to the anode of the first diode, the cathode of the first diode is used to receive the power supply voltage, and the anode of the first diode is the output terminal of the first voltage detection unit.

[0012] The first voltage detection unit further includes a first resistor, a first capacitor, a second resistor, a third resistor, a fourth resistor, a Zener diode, a fifth resistor, a sixth resistor, a seventh resistor, and a second capacitor. One end of the first resistor is connected to the first control unit, and the other end of the first resistor is connected to one end of the first capacitor, one end of the second resistor, and the control terminal of the fifth switching transistor. The other ends of the first capacitor, the second resistor, and the fifth switching transistor are all grounded. The first end of the fifth switching transistor is connected to one end of the third resistor. The other end of the third resistor is connected to the control terminal of the sixth switching transistor, one end of the fourth resistor, and the positive terminal of the Zener diode. The other end of the fourth resistor and the negative terminal of the Zener diode are connected to the first end of the sixth switching transistor. The first end of the sixth switching transistor is the detection terminal of the first voltage detection unit. The second end of the sixth switching transistor is connected to one end of the fifth resistor. The other end of the fifth resistor is connected to one end of the sixth resistor and one end of the seventh resistor. One end of the second capacitor and the other end of the sixth resistor are both grounded. The other end of the seventh resistor and the other end of the second capacitor are connected to the positive terminal of the first diode.

[0013] The second voltage detection unit includes an eighth resistor, a ninth resistor, a tenth resistor, a third capacitor, and a second diode. One end of the eighth resistor is the detection terminal of the second voltage detection unit, and the other end of the eighth resistor is connected to one end of the ninth resistor and one end of the tenth resistor. One end of the third capacitor and the other end of the ninth resistor are both grounded. The other end of the tenth resistor and the other end of the third capacitor are connected to the positive terminal of the second diode. The negative terminal of the second diode is used to connect to the power supply voltage, and the positive terminal of the second diode is the output terminal of the second voltage detection unit.

[0014] The second battery module also includes an inductor current acquisition unit, which includes a current sampler, an eleventh resistor, a third diode, and a fourth capacitor. The first detection terminal of the current sampler is connected to one end of the inductor, the second detection terminal of the current sampler is connected to the other end of the inductor, the output terminal of the current sampler is connected to one end of the eleventh resistor, the other end of the eleventh resistor is connected to the positive terminal of the third diode and one end of the fourth capacitor, the negative terminal of the third diode is used to receive the power supply voltage, the other end of the fourth capacitor is grounded, and the positive terminal of the third diode is connected to the first control unit.

[0015] The beneficial effects of this application are as follows: Unlike the prior art, in the technical solution of this application, the power supply circuit includes a first battery module and at least one second battery module. One end of the first battery is connected to one end of a first charge-discharge switch unit. The other end of the first charge-discharge switch unit and the other end of the first battery together serve as a first parallel terminal. One end of the second battery is connected to one end of a second charge-discharge switch unit and one end of a DC-DC conversion circuit. The other end of the second charge-discharge switch unit is connected to the other end of the DC-DC conversion circuit. The other end of the second charge-discharge switch unit and the other end of the second battery together serve as a second parallel terminal. The first parallel terminal is connected to the second parallel terminal to connect the first battery module and the second battery module in parallel. Based on the above method, a DC-DC conversion circuit can be set in the second battery module without the need to set a DC-DC conversion circuit in the first battery module. When the first and second battery modules are connected in parallel, the output voltage of the second battery module can be adjusted through the DC-DC conversion circuit of the second battery module to reduce the voltage difference between the two battery modules. Based on the above method, a power supply circuit with strong power supply capability can be constructed by connecting the first and second battery modules in parallel without setting a DC-DC conversion circuit in the first battery module but setting a current conversion circuit in the second battery module. Furthermore, since the DC-DC conversion circuit is not required in the first battery module, the overall volume and weight of the power supply circuit are reduced, thereby reducing the cost of the power supply circuit without affecting its power supply capability. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structure of one embodiment of the power supply circuit of this application;

[0018] Figure 2 This is a schematic diagram of the structure of an embodiment of the first battery module of this application;

[0019] Figure 3 This is a schematic diagram of the structure of an embodiment of the second battery module of this application;

[0020] Figure 4 This is a schematic diagram of the structure of an embodiment of the first voltage detection unit of this application;

[0021] Figure 5 This is a schematic diagram of the structure of an embodiment of the second voltage detection unit of this application;

[0022] Figure 6 This is a schematic diagram of the structure of an embodiment of the inductor current detection unit of this application;

[0023] Figure 7 This is a schematic diagram of the structure of one embodiment of the power supply device of this application.

[0024] The attached figures are labeled as follows: 1. First battery module; 11. First battery; 12. First charge / discharge switch unit; 13. Second fuse; 14. Precharge / discharge switch unit; 15. Second control unit; 2. Second battery module; 21. Second battery; 22. Second charge / discharge switch unit; 23. DC-DC conversion circuit; 24. First control unit; 25. First fuse; 26. Current sampler; 30. Power supply device; 31. Power supply circuit. Detailed Implementation

[0025] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It is understood that the specific embodiments described herein are only for explaining this application and not for limiting it. Furthermore, it should be noted that, for ease of description, only the parts related to this application are shown in the accompanying drawings, not all structures. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0026] The terms "first," "second," and "third" in this application are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. All directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of this application are only used to explain the relative positional relationships and movements between components in a specific orientation (as shown in the figures). If the specific orientation changes, the directional indications also change accordingly. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to these processes, methods, products, or devices.

[0027] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0028] This application proposes a power supply circuit, see [link to relevant documentation] Figures 1 to 3 , Figure 1 This is a schematic diagram of one embodiment of the power supply circuit of this application. Figure 2 This is a schematic diagram of the structure of an embodiment of the first battery module of this application. Figure 3 This is a schematic diagram of the structure of an embodiment of the second battery module of this application.

[0029] like Figure 1 As shown, the power supply circuit includes a first battery module 1 and at least one second battery module 2. Specifically, the first battery module 1 can refer to a main battery pack, and the second battery module 2 can refer to a secondary battery pack. The power supply circuit can be composed of a main battery pack and at least one secondary battery pack connected in parallel, enabling the power supply circuit to be configured with corresponding power supply and / or energy storage capabilities by adding the required number of secondary battery packs to the existing main battery pack.

[0030] The first battery module 1 includes a first battery 11 and a first charge / discharge switch unit 12. One end of the first battery 11 is connected to one end of the first charge / discharge switch unit 12, and the other end of the first charge / discharge switch unit 12 and the other end of the first battery 11 together serve as a first parallel terminal. Wherein, as... Figure 2 As shown, the other end of the first battery 11 is also grounded, the other end of the first charge and discharge switch unit 12 can refer to the first sub-terminal E1, and the other end of the first battery 11 can refer to the second sub-terminal E2. The first sub-terminal E1 and the second sub-terminal E2 can be used as the positive and negative terminals of the first battery module 1.

[0031] The second battery module 2 includes a second battery 21, a second charge / discharge switch unit 22, and a DC-DC conversion circuit 23. One end of the second battery 21 is connected to one end of the second charge / discharge switch unit 22 and one end of the DC-DC conversion circuit 23, respectively. The other end of the second charge / discharge switch unit 22 is connected to the other end of the DC-DC conversion circuit 23. The other end of the second charge / discharge switch unit 22 and the other end of the second battery 21 together serve as a second parallel terminal. Wherein, as... Figure 3 As shown, the other end of the second battery 21 is also grounded. The second battery module 2 has at least two second parallel terminals. In one second parallel terminal, the other end of the second charge / discharge switch unit 22 can refer to the third sub-terminal F1, and the other end of the second battery 21 can refer to the fourth sub-terminal F2. In the other second parallel terminal, the other end of the second charge / discharge switch unit 22 can refer to the fifth sub-terminal F3, and the other end of the second battery 21 can refer to the sixth sub-terminal F4. The third sub-terminal F1 and the fourth sub-terminal F2 can be used as the positive and negative terminals of one second parallel terminal of the first battery module 1, and the fifth sub-terminal F3 and the sixth sub-terminal F4 can be used as the positive and negative terminals of the other second parallel terminal of the first battery module 1.

[0032] The first parallel terminal is connected to the second parallel terminal to connect the first battery module 1 and the second battery module 2 in parallel.

[0033] The number of second battery modules 2 is N. These N can be one, two, or more, and there is no limitation here.

[0034] When there is only one second battery module 2, the positive terminal of the first battery module 1 can be connected to the positive terminal of the second battery module 2, and the negative terminal of the first battery module 1 can be connected to the negative terminal of the second battery module 2.

[0035] When there are two or more second battery modules 2, the fifth sub-terminal F3 of one second battery module 2 can be connected to the third sub-terminal F1 of another second battery module 2, and the sixth sub-terminal F4 of one second battery module 2 can be connected to the fourth sub-terminal F2 of another second battery module 2, so that the second battery modules 2 are connected in parallel. Also, the positive terminal of the first battery module 1 is connected to the positive terminal of the corresponding second battery module 2 that is not connected to the second battery module 2, and the negative terminal of the first battery module 1 is connected to the negative terminal of the corresponding second battery module 2 that is not connected to the second battery module 2. In summary, the second battery modules 2 can be connected in parallel, and the first battery module 1 can be connected in parallel with the second battery modules 2 that are connected in parallel, so as to realize the parallel connection of all battery modules.

[0036] Specifically, in the parallel power supply circuit constructed in the above manner, a DC-DC converter circuit is provided in the second battery module 2, eliminating the need for a DC-DC converter circuit in the first battery module 1. However, firstly, it is still possible to adjust the output voltage of the second battery module 2 through the DC-DC converter circuit when there is a voltage difference between the first battery module 1 and the second battery module 2. This allows for power balance between the first battery module 1 and the second battery module 2 when the voltage difference is small after DC-DC conversion, thereby reducing the voltage difference before DC-DC conversion. Alternatively, it can enable the parallel connection between the first battery module 1 and the second battery module 2 for parallel operation when the voltage difference is eliminated after DC-DC conversion. Secondly, similarly, a DC-DC converter circuit can also be used between the second battery modules 2 to adjust the output voltage of at least one second battery module 2. This allows for power balance between the second battery modules 2 when the voltage difference is small after DC-DC conversion, thereby reducing the voltage difference before DC-DC conversion. Alternatively, it can enable the parallel connection between the second battery modules 2 for parallel operation when the voltage difference is eliminated after DC-DC conversion.

[0037] In summary, based on the above approach, while ensuring that the battery modules in the power supply circuit can perform normal circulating current control to reduce the voltage difference between battery modules under appropriate conditions, the number of DC-DC conversion circuits required in the power supply circuit can be reduced. This not only reduces the overall size and weight of the power supply circuit, thereby reducing the cost of the power supply circuit without affecting its power supply capacity, but also increases the user's freedom to set the number of battery modules in the power supply circuit according to their own needs, thus improving the portability and reliability of the power supply circuit.

[0038] In addition, it should be noted that, as Figure 2As shown, the first charge-discharge switch unit 12 may specifically include a seventh switch tube Q7 and an eighth switch tube Q8. The first end of the seventh switch tube Q7 serves as one end of the first charge-discharge switch unit 12, the second end of the seventh switch tube Q7 is connected to the first end of the eighth switch tube Q8, and the second end of the eighth switch tube Q8 serves as the other end of the first charge-discharge switch unit 12.

[0039] like Figure 3 As shown, the second charge / discharge switch unit 22 may specifically include a ninth switch tube Q9 and a tenth switch tube Q10. The first end of the ninth switch tube Q9 serves as one end of the second charge / discharge switch unit 22, the second end of the ninth switch tube Q9 is connected to the first end of the tenth switch tube Q10, and the second end of the tenth switch tube Q10 serves as the other end of the second charge / discharge switch unit 22.

[0040] Unlike existing technologies, in the technical solution of this application, the power supply circuit includes a first battery module and at least one second battery module. One end of the first battery is connected to one end of a first charge-discharge switch unit. The other end of the first charge-discharge switch unit and the other end of the first battery together serve as a first parallel terminal. One end of the second battery is connected to one end of a second charge-discharge switch unit and one end of a DC-DC converter circuit. The other end of the second charge-discharge switch unit is connected to the other end of the DC-DC converter circuit. The other end of the second charge-discharge switch unit and the other end of the second battery together serve as a second parallel terminal. The first parallel terminal is connected to the second parallel terminal to connect the first battery module and the second battery module in parallel. Based on the above method, a DC-DC conversion circuit can be set in the second battery module without the need to set a DC-DC conversion circuit in the first battery module. When the first and second battery modules are connected in parallel, the output voltage of the second battery module can be adjusted through the DC-DC conversion circuit of the second battery module to reduce the voltage difference between the two battery modules. Based on the above method, a power supply circuit with strong power supply capability can be constructed by connecting the first and second battery modules in parallel without setting a DC-DC conversion circuit in the first battery module but setting a current conversion circuit in the second battery module. Furthermore, since the DC-DC conversion circuit is not required in the first battery module, the overall volume and weight of the power supply circuit are reduced, thereby reducing the cost of the power supply circuit without affecting its power supply capability.

[0041] In one embodiment, such as Figure 1 As shown, the first battery module 1 also includes a second fuse 13, a precharge / discharge switch unit 14, and a current-limiting resistor RX.

[0042] The second fuse 13 is connected to one end of the DC-DC conversion circuit 23 and one end of the pre-charge and discharge switch unit 14. The other end of the pre-charge and discharge switch unit 14 is connected to one end of the current limiting resistor RX. The other end of the current limiting resistor RX and the other end of the first battery 11 together serve as the first parallel terminal.

[0043] Specifically, such as Figure 2 As shown, the pre-charge and discharge switch unit 14 may specifically include an eleventh switch transistor Q11 and a twelfth switch transistor Q12. The first end of the eleventh switch transistor Q11 serves as one end of the pre-charge and discharge switch unit 14, the second end of the eleventh switch transistor Q11 is connected to the first end of the twelfth switch transistor Q12, and the second end of the twelfth switch transistor Q12 serves as the other end of the pre-charge and discharge switch unit 14.

[0044] For example, assuming the power supply circuit is in a power-off state with all switching units disconnected, the power supply circuit's operating procedure may include:

[0045] S11: In response to receiving the power-on command of the first battery module 1, the temperature of the current-limiting resistor RX is detected.

[0046] S12: If the temperature of the current-limiting resistor RX is not less than the preset temperature threshold, the process ends, fault information is output and / or the preset time is waited for the process to be re-executed in step S11 and subsequent steps.

[0047] In response to the temperature of the current-limiting resistor RX being lower than a preset temperature threshold, the pre-charge and discharge switch unit 14 is turned on to pre-charge the power-on components (such as capacitors) in the device powered by the power supply circuit through the first battery module 1.

[0048] S13: In response to the voltage of the first battery 11 being less than a preset first battery voltage threshold, or the voltage of the first battery 11 being not less than the preset first battery voltage threshold, and the voltage at the first parallel terminal of the first battery module 1 being less than the preset first parallel terminal voltage threshold, the process ends, fault information is output and / or a preset time is waited for re-execution of step S11 and subsequent steps.

[0049] In response to the voltage of the first battery 11 being not less than a preset first battery voltage threshold and the voltage at the first parallel terminal of the first battery module 1 being not less than a preset first parallel terminal voltage threshold (i.e., when the power-on standby charging component powered by the first battery module 1 is fully charged), the pre-charge and discharge switch unit 14 is disconnected and the first charge and discharge switch unit 12 is turned on, so that the connection between the first battery module 1 and the first parallel terminal is turned on.

[0050] This completes the connection of the first battery module 1 during the power circuit's transition from the off state to the on state.

[0051] By setting a current-limiting resistor RX, the current passing through the pre-charge / discharge switch unit 14 can be limited when it is turned on, reducing the possibility of overcurrent and improving safety. Furthermore, by setting a second fuse 13, the circuit containing the pre-charge / discharge switch unit 14 can be disconnected in the event of an overcurrent, reducing the possibility of damage to the pre-charge / discharge switch unit 14, the first battery 11, or other components, further improving safety.

[0052] Based on the above method, the safety of the pre-charging process in step S12 can be improved.

[0053] Optionally, the first battery module 1 further includes a second control unit 15, which can be connected to the control terminals of the seventh switch Q7, the eighth switch Q8, the eleventh switch Q11, and the twelfth switch Q12 respectively, so as to realize the control of the pre-charge and discharge switch unit 14 and the first charge and discharge switch unit 12 to turn on and off respectively.

[0054] In one embodiment, such as Figure 3 As shown, the DC-DC converter circuit 23 includes a first switch Q1, a second switch Q2, a third switch Q3, a fourth switch Q4, and an inductor L.

[0055] One end of the first switch Q1 serves as one end of the DC-DC converter circuit 23. The other end of the first switch Q1 is connected to one end of the second switch Q2 and one end of the inductor L. The other end of the inductor L is connected to one end of the third switch Q3 and one end of the fourth switch Q4. The other ends of the second switch Q2 and the fourth switch Q4 are both grounded. The other end of the third switch Q3 serves as the other end of the DC-DC converter circuit 23.

[0056] Specifically, the DC-DC converter circuit 23 constructed above can also be called a four-switch DC-DC converter circuit. The four-switch DC-DC converter circuit can switch between bidirectional BUCK mode and BUCK-BOOST mode. The bidirectional BUCK mode is characterized by its inability to perform DC-DC conversion under low voltage difference and its large heat generation power, but its high DC-DC conversion efficiency. The BUCK-BOOST mode is characterized by its ability to perform DC-DC conversion under low voltage difference and its small heat generation power, but its low DC-DC conversion efficiency.

[0057] The following are some special operating conditions caused by temperature or battery internal resistance:

[0058] First, in low-temperature environments, the battery module cannot withstand large charging currents. However, when the voltage difference is too small, the bidirectional BUCK circuit cannot effectively perform DC-DC conversion to achieve circulating current control. Therefore, if only the bidirectional BUCK circuit is set, there is a high probability that the charging current of the low-voltage battery module will be too large, causing damage and affecting its lifespan.

[0059] Secondly, when the battery module discharges with a large discharge current or charges with a large charging current, the external voltage received by the battery module will be low due to the low internal resistance of the battery. If the battery modules are directly connected in parallel at this time, the discharge current of the high-voltage battery module may be too large or the charging current of the low-voltage battery module may be too large, causing overcurrent, damaging the battery module and affecting its lifespan.

[0060] In the special operating conditions exemplified above, as well as in other operating conditions with small voltage differentials and large currents, if only a bidirectional BUCK circuit with bidirectional BUCK function is set as a DC-DC conversion circuit, it is easy to fail to accurately control the circulating current, which may damage the battery and result in poor reliability.

[0061] Therefore, by setting the four-switch DC-DC converter circuit in each of the second battery modules 2, the DC-DC converter circuit 23 can be controlled in different modes to adjust the differential pressure when performing circulating current control between the battery modules in the face of different types of differential pressure, temperature or DC-DC conversion efficiency requirements, thereby improving the flexibility and reliability of the power supply circuit.

[0062] Furthermore, it should be noted that when there is a voltage difference between the two battery modules, according to Ohm's law, if the voltage difference between the two battery modules remains constant, the smaller the resistance, the greater the current generated by the voltage difference. However, since the internal resistance of the current battery modules and the structural internal resistance between the two battery modules are set relatively small to reduce resistive heating or losses, and it is difficult to change these internal resistances, excessive circulating current will also lead to a decrease in the lifespan of the battery modules. Therefore, under the above premise, choosing to use a DC-DC converter circuit to reduce the voltage difference between the battery modules to reduce the circulating current between the battery modules is a more reliable and safe circulating current control method. When the voltage difference between the battery modules is reduced or eliminated through circulating current control, the battery modules can be used in parallel.

[0063] Optionally, the second battery module 2 further includes a first control unit 24, which is connected to the control terminals of the first switch Q1, the second switch Q2, the third switch Q3, the fourth switch Q4, and the second charge / discharge switch unit 22. The control terminals of the second charge / discharge switch unit 22 may include the control terminals of the ninth switch Q9 and the tenth switch Q10, so as to control the DC-DC conversion circuit 23 and the second charge / discharge switch unit 22 to be turned on and off, respectively.

[0064] Specifically, in the DC-DC conversion circuit 23 and the second charge-discharge switch unit 22, only one of them is turned on at the same time, that is, the DC conversion function of the DC-DC conversion circuit 23 and the charge-discharge control function of the second charge-discharge switch unit 22 are not performed simultaneously.

[0065] Based on the above method, it is possible to control the DC-DC conversion function and the charge / discharge control function of the second battery module 2 with only one first control unit 24, thereby reducing cost, size and weight, and improving the ease of use of the power supply circuit.

[0066] Optionally, the second battery module 2 further includes a first fuse 25, which is connected to one end of the second battery 21 and one end of the DC-DC conversion circuit 23.

[0067] Specifically, by setting the first fuse 25, the conduction of the line where the DC-DC conversion circuit 23 is located can be disconnected when an overcurrent occurs, reducing the possibility of damage to the DC-DC conversion circuit 23, the second battery 21, or other devices caused by the overcurrent, and further improving safety.

[0068] For example, after completing the connection of the first battery module 1, the usage process of the above power circuit may also include:

[0069] S21: In response to receiving the power-on command for the second battery module 2, the voltage received by the second battery module 2 is detected and external status commands (such as CAN message information) are received to determine the external status. Specifically, the voltage received by the second battery module 2 can be the voltage jointly provided by the first battery module 1 and other devices, that is, the voltage directly received by the second battery module 2 from its second parallel terminal.

[0070] S22: In response to the voltage difference between the voltage received by the second battery module 2 and the voltage of the second battery 21 of the second battery module 2 being less than a preset voltage difference threshold, the DC-DC conversion circuit 23 of the second battery module 2 is disconnected and the second charge-discharge switch unit 22 is turned on, thus completing the connection operation of the second battery module 2 during the process of the power circuit completing the transition from the off state to the on state.

[0071] In response to the voltage difference between the voltage received by the second battery module 2 and the voltage of the second battery 21 of the second battery module 2 being not less than a preset voltage difference threshold, the DC-DC conversion circuit 23 of the second battery module 2 is turned on and the second charge-discharge switch unit 22 is turned off. After the voltage output by the second battery module 2 is converted to DC, it is subjected to circulating current control with the external voltage to reduce the voltage difference and improve the parallel operation environment. Until the voltage difference between the voltage received by the second battery module 2 and the voltage of the second battery 21 of the second battery module 2 is less than the preset voltage difference threshold, the DC-DC conversion circuit 23 of the second battery module 2 is turned off and the second charge-discharge switch unit 22 is turned on, completing the connection operation of the second battery module 2 during the power supply circuit's transition from the off state to the on state.

[0072] Thus, after completing the connection of all the second battery modules 2 in the above manner, the parallel operation is completed. That is, the first battery module 1 and each second battery module 2 that are connected in parallel can be charged and discharged at the same time, realizing the construction of a large-capacity battery based on multiple battery modules 2 and improving the power supply capacity of the power circuit.

[0073] The circulating flow control process in S22 above may specifically include:

[0074] S31: Obtain the cell temperature of the second battery module 2, and determine the above-mentioned preset differential pressure threshold of the second battery module 2 based on the cell temperature.

[0075] S32: Obtain the voltage received by the second battery module 2, denoted as the external voltage, and obtain the voltage of the second battery 21 of the second battery module 2, denoted as the battery voltage.

[0076] S33: In response to the external voltage being lower than the battery voltage, the second battery module 2 is controlled to enter the output mode and wait for the second battery module 2 to discharge.

[0077] In response to an external voltage not being less than the battery voltage, the second battery module 2 is controlled to enter the input mode and wait for charging.

[0078] S34: In response to the difference between the external voltage and the battery voltage being greater than the mode switching voltage difference threshold, the DC-DC conversion circuit 23 is controlled to enter the bidirectional BUCK mode.

[0079] If the difference between the external voltage and the battery voltage is not greater than the mode switching voltage difference threshold, the DC-DC conversion circuit 23 is controlled to enter the BUCK-BOOST mode.

[0080] S35: Control the second battery module 2 to perform circulating current control based on the DC-DC conversion circuit 23, so as to charge or discharge under the action of the DC-DC conversion circuit 23 in the corresponding mode, reduce the difference between the external voltage and the battery voltage, until the voltage difference between the voltage received by the second battery module 2 and the voltage of the second battery 21 of the second battery module 2 is less than the preset voltage difference threshold.

[0081] Based on the above method, the power supply circuit provided by the technical solution of this application can reduce the number of DC-DC conversion circuits 23 and reasonably set the type of DC-DC conversion circuit 23 to achieve more reliable circulating current control that can cope with various operating conditions, thereby improving the reliability and safety of the power supply circuit.

[0082] In one embodiment, based on the previous embodiment in which the second battery module 2 also includes a first control unit 24, the second battery module 2 may further include at least one of a first voltage detection unit, a second voltage detection unit, and a battery current detection unit.

[0083] The detection terminal of the first voltage detection unit is connected to one end of the second battery 21, and the output terminal of the first voltage detection unit is connected to the first control unit 24.

[0084] Alternatively, the detection terminal of the second voltage detection unit is connected to the other end of the second charge / discharge switch unit 22, and the output terminal of the second voltage detection unit is connected to the first control unit 24.

[0085] Alternatively, the first detection terminal of the battery current detection unit is connected to one end of the second battery 21, the second detection terminal of the battery current detection unit is connected to the other end of the second battery 21, and the output terminal of the battery current detection unit is connected to the first control unit 24.

[0086] Specifically, the above describes the detection units that can be installed in the second battery module 2 and their connection methods. Similarly, at least one of the corresponding first voltage detection unit, second voltage detection unit, and battery current detection unit can also be installed in the first battery module 1, as illustrated below:

[0087] Based on the embodiment described above where the first battery module 1 includes the second control unit 15, the first battery module 1 may further include at least one of a first voltage detection unit, a second voltage detection unit, and a battery current detection unit.

[0088] The detection terminal of the first voltage detection unit is connected to one end of the first battery 11, and the output terminal of the first voltage detection unit is connected to the second control unit 15.

[0089] Alternatively, the detection terminal of the second voltage detection unit is connected to the other end of the first charge / discharge switch unit 12, and the output terminal of the second voltage detection unit is connected to the second control unit 15.

[0090] Alternatively, the first detection terminal of the battery current detection unit is connected to one end of the first battery 11, the second detection terminal of the battery current detection unit is connected to the other end of the first battery 11, and the output terminal of the battery current detection unit is connected to the second control unit 15.

[0091] In summary, based on the above method, the corresponding voltage or current in the second battery module 2 can be detected by each detection unit set in the second battery module 2, and the corresponding voltage or current in the first battery module 1 can also be detected by each detection unit set in the first battery module 1.

[0092] The detection terminal of the first voltage detection unit can be connected to one end of the first battery 11 or one end of the second battery 21, such as... Figure 2 or Figure 3 Point X, as shown, is used to detect the voltage at one end of the first battery 11 or one end of the second battery 21, that is, the battery voltage corresponding to the corresponding battery module, such as the voltage of the second battery 21 of the second battery module 2 mentioned in the previous embodiment.

[0093] The detection terminal of the second voltage detection unit can be used to connect to the other end of the first charge / discharge switch unit 12 or the other end of the second charge / discharge switch unit 22, such as... Figure 2 or Figure 3 Point Y, as shown, is used to detect the voltage at the other end of the first charge / discharge switch unit 12 or the other end of the second charge / discharge switch unit 22, which is the external voltage corresponding to the battery module, such as the voltage received by the second battery module 2 mentioned in the previous embodiment.

[0094] The battery current detection unit can be used to connect to both ends of the battery of the corresponding battery module to detect the current output by the battery of the corresponding battery module.

[0095] For example, such as Figure 2 and Figure 3 As shown, the first battery module 1 further includes a second control unit 15, and / or the second battery module 2 further includes a first control unit 24.

[0096] First, see Figure 4 , Figure 4 This is a schematic diagram of the structure of an embodiment of the first voltage detection unit of this application, as shown below. Figure 4 As shown, the first voltage detection unit includes a fifth switch Q5, a sixth switch Q6, and a first diode D1.

[0097] The control terminal of the fifth switch Q5 is connected to the first control unit. The first terminal of the fifth switch Q5 is connected to the control terminal of the sixth switch Q6. The second terminal of the fifth switch Q5 is grounded. The first terminal of the sixth switch Q6 is the detection terminal of the first voltage detection unit. The second terminal of the sixth switch Q6 is connected to the positive terminal of the first diode D1. The negative terminal of the first diode D1 is used to receive the power supply voltage. The positive terminal of the first diode D1 is the output terminal of the first voltage detection unit.

[0098] Specifically, such as Figure 4 As shown, the first voltage detection unit may include a first resistor R1, a first capacitor C1, a second resistor R2, a fifth switch Q5, a third resistor R3, a sixth switch Q6, a fourth resistor R4, a Zener diode ZD, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, a second capacitor C2, and a first diode D1.

[0099] One end of the first resistor R1 is connected to the second control unit 15 or the first control unit 24 to receive the corresponding detection start / stop signals. The other end of the first resistor R1 is connected to one end of the first capacitor C1, one end of the second resistor R2, and the control terminal of the fifth switch Q5. The other ends of the first capacitor C1, the second resistor R2, and the second terminal of the fifth switch Q5 are all grounded. The first terminal of the fifth switch Q5 is connected to one end of the third resistor R3. The other end of the third resistor R3 is connected to the control terminal of the sixth switch Q6, one end of the fourth resistor R4, and the positive terminal of the Zener diode ZD. The other end of the fourth resistor R4 and the negative terminal of the Zener diode ZD are respectively... The first terminal of the sixth switch Q6 is connected to the detection terminal of the first voltage detection unit. The second terminal of the sixth switch Q6 is connected to one end of the fifth resistor R5. The other end of the fifth resistor R5 is connected to one end of the sixth resistor R6 and one end of the seventh resistor R7. One end of the second capacitor C2 and the other end of the sixth resistor R6 are both grounded. The other end of the seventh resistor R7 and the other end of the second capacitor C2 are connected to the positive terminal of the first diode D1. The negative terminal of the first diode D1 is used to receive the power supply voltage. The positive terminal of the first diode D1 is the output terminal of the first voltage detection unit, which is used to connect to the second control unit 15 or the first control unit 24.

[0100] Based on the above methods, such as Figure 4As shown, different levels can be input at endpoint M1 (one end of the first resistor R1) by the second control unit 15 or the first control unit 24 to control the fifth switch Q5 and the sixth switch Q6, so as to control whether the signal at endpoint M2 (the detection end of the first voltage detection unit) can be sent to endpoint M3 (the second control unit 15 or the first control unit 24). That is, the second control unit 15 or the first control unit 24 can control whether the first voltage detection unit is enabled or not, reducing unnecessary energy consumption, and enabling the detection of the battery voltage at point X when needed.

[0101] Second, see Figure 5 , Figure 5 This is a schematic diagram of the structure of an embodiment of the second voltage detection unit of this application, as shown below. Figure 5 As shown, the second voltage detection unit includes an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, a third capacitor C3, and a second diode D2.

[0102] One end of the eighth resistor R8 is the detection terminal of the second voltage detection unit. The other end of the eighth resistor R8 is connected to one end of the ninth resistor R9 and one end of the tenth resistor R10. One end of the third capacitor C3 and the other end of the ninth resistor R9 are both grounded. The other end of the tenth resistor R10 and the other end of the third capacitor C3 are connected to the positive terminal of the second diode D2. The negative terminal of the second diode D2 is used to receive the power supply voltage. The positive terminal of the second diode D2 is the output terminal of the second voltage detection unit, which is used to connect to the second control unit 15 or the first control unit 24.

[0103] Based on the above methods, such as Figure 5 As shown, the signal from endpoint M4 (the detection end of the second voltage detection unit) can be transmitted to endpoint M5 (the second control unit 15 or the first control unit 24) to realize the detection of the external voltage at point Y.

[0104] In one embodiment, based on the embodiment where the DC-DC conversion circuit 23 includes a first switch Q1, a second switch Q2, a third switch Q3, a fourth switch Q4 and an inductor L, and the second battery module 2 also includes a first control unit 24, the second battery module 2 further includes an inductor current acquisition unit.

[0105] See Figure 6 , Figure 6 This is a schematic diagram of the structure of an embodiment of the inductor current detection unit of this application, as shown below. Figure 6 As shown, the inductor current acquisition unit includes a current sampler 26, an eleventh resistor R11, a third diode D3, and a fourth capacitor C4.

[0106] The first detection terminal of the current sampler 26 is connected to one end of the inductor L, the second detection terminal of the current sampler 26 is connected to the other end of the inductor L, the output terminal of the current sampler 26 is connected to one end of the eleventh resistor R11, the other end of the eleventh resistor R11 is connected to the positive terminal of the third diode D3 and one end of the fourth capacitor C4 respectively, the negative terminal of the third diode D3 is used to receive the power supply voltage, the other end of the fourth capacitor C4 is grounded, and the positive terminal of the third diode D3 is connected to the first control unit 24.

[0107] Specifically, the first detection terminal IN- of the current sampler 26 can be used to receive the signal PI- from one end of the inductor L, and the second detection terminal IN+ of the current sampler 26 can be used to receive the signal PI+ from the other end of the inductor L. The ground terminal GND of the current sampler 26 can be grounded. The power supply terminal VS of the current sampler 26 can be connected to one end of the first power supply resistor, one end of the second power supply resistor, and one end of the first power supply capacitor, respectively. The other end of the first power supply resistor is used to receive the first power supply voltage 3V3, the other end of the second power supply resistor is used to receive the second power supply voltage 5V, and the other end of the first power supply capacitor is grounded. The first reference terminal REF1 and the second reference terminal REF2 of the current sampler 26 are used to receive the reference voltage +1.5V, respectively. The unused terminal of the current sampler 26 is grounded and connected to one end of the unused capacitor. The other end of the unused capacitor is used to receive the reference voltage +1.5V. The output terminal OUT of the current sampler 26 is used to output the voltage signal converted from the detection result of the intensity and direction of the current on the inductor L.

[0108] Based on the above method, the intensity and direction of the current on the inductor L can be detected by the current sampler 26, and converted into a corresponding voltage signal and sent to the terminal M6 (second control unit 15 or first control unit 24) to complete the detection.

[0109] The control units mentioned in the preceding embodiments can be microcontrollers or other types of devices or circuits with processing capabilities, and are not limited here.

[0110] It should be noted that, as Figures 4 to 6 As shown, the voltages of the power supplies with a voltage amplitude of 3V3 (i.e., 3.3 volts) can be provided by the same voltage source or by different voltage sources; this is not limited here.

[0111] Furthermore, in other circuits, the voltages of the same power supply may be provided by the same voltage source or by different voltage sources; this is not limited here.

[0112] This application also proposes a power supply device, see [link to document]. Figure 7 , Figure 7 This is a schematic diagram of the structure of one embodiment of the power supply device of this application, as shown below. Figure 7 As shown, the power supply device 30 includes a power supply circuit 31, which can be the power supply circuit described in any of the preceding embodiments, and will not be repeated here.

[0113] Unlike existing technologies, in the technical solution of this application, the power supply circuit includes a first battery module and at least one second battery module. One end of the first battery is connected to one end of a first charge-discharge switch unit. The other end of the first charge-discharge switch unit and the other end of the first battery together serve as a first parallel terminal. One end of the second battery is connected to one end of a second charge-discharge switch unit and one end of a DC-DC converter circuit. The other end of the second charge-discharge switch unit is connected to the other end of the DC-DC converter circuit. The other end of the second charge-discharge switch unit and the other end of the second battery together serve as a second parallel terminal. The first parallel terminal is connected to the second parallel terminal to connect the first battery module and the second battery module in parallel. Based on the above method, a DC-DC conversion circuit can be set in the second battery module without the need to set a DC-DC conversion circuit in the first battery module. When the first and second battery modules are connected in parallel, the output voltage of the second battery module can be adjusted through the DC-DC conversion circuit of the second battery module to reduce the voltage difference between the two battery modules. Based on the above method, a power supply circuit with strong power supply capability can be constructed by connecting the first and second battery modules in parallel without setting a DC-DC conversion circuit in the first battery module but setting a current conversion circuit in the second battery module. Furthermore, since the DC-DC conversion circuit is not required in the first battery module, the overall volume and weight of the power supply circuit are reduced, thereby reducing the cost of the power supply circuit without affecting its power supply capability.

[0114] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A power supply circuit, characterized in that, Includes a first battery module and at least one second battery module; The first battery module includes a first battery and a first charge-discharge switch unit. One end of the first battery is connected to one end of the first charge-discharge switch unit, and the other end of the first charge-discharge switch unit and the other end of the first battery together serve as the first parallel terminal. The second battery module includes a second battery, a second charge / discharge switch unit, and a DC-DC conversion circuit. One end of the second battery is connected to one end of the second charge / discharge switch unit and one end of the DC-DC conversion circuit, respectively. The other end of the second charge / discharge switch unit is connected to the other end of the DC-DC conversion circuit. The other end of the second charge / discharge switch unit and the other end of the second battery together serve as a second parallel terminal. The first parallel terminal is connected to the second parallel terminal to connect the first battery module and the second battery module in parallel.

2. The power supply circuit according to claim 1, characterized in that, The DC-DC conversion circuit includes a first switching transistor, a second switching transistor, a third switching transistor, a fourth switching transistor, and an inductor; One end of the first switching transistor serves as one end of the DC-DC conversion circuit. The other end of the first switching transistor is connected to one end of the second switching transistor and one end of the inductor. The other end of the inductor is connected to one end of the third switching transistor and one end of the fourth switching transistor. The other ends of the second and fourth switching transistors are both grounded. The other end of the third switching transistor serves as the other end of the DC-DC conversion circuit.

3. The power supply circuit according to claim 2, characterized in that, The second battery module also includes a first control unit, which is connected to the control terminals of the first switching transistor, the second switching transistor, the third switching transistor, the fourth switching transistor, and the second charge / discharge switch unit.

4. The power supply circuit according to claim 2, characterized in that, The second battery module also includes a first fuse, which is connected to one end of the second battery and one end of the DC-DC conversion circuit.

5. The power supply circuit according to any one of claims 1 to 4, characterized in that, The first battery module also includes a second fuse, a pre-charge / discharge switch unit, and a current-limiting resistor; The second fuse is connected to one end of the DC-DC converter circuit and one end of the pre-charge-discharge switch unit. The other end of the pre-charge-discharge switch unit is connected to the other end of the DC-DC converter circuit. The other end of the current-limiting resistor and the other end of the first battery together serve as the first parallel terminal.

6. The power supply circuit according to claim 3, characterized in that, The second battery module further includes at least one of a first voltage detection unit, a second voltage detection unit, and a battery current detection unit; The detection terminal of the first voltage detection unit is connected to one end of the second battery, and the output terminal of the first voltage detection unit is connected to the first control unit; Alternatively, the detection terminal of the second voltage detection unit is connected to the other end of the second charge / discharge switch unit, and the output terminal of the second voltage detection unit is connected to the first control unit; Alternatively, the first detection terminal of the battery current detection unit is connected to one end of the second battery, the second detection terminal of the battery current detection unit is connected to the other end of the second battery, and the output terminal of the battery current detection unit is connected to the first control unit.

7. The power supply circuit according to claim 6, characterized in that, The first voltage detection unit includes a fifth switch, a sixth switch, and a first diode; The control terminal of the fifth switch is connected to the first control unit, the first terminal of the fifth switch is connected to the control terminal of the sixth switch, the second terminal of the fifth switch is grounded, the first terminal of the sixth switch is the detection terminal of the first voltage detection unit, the second terminal of the sixth switch is connected to the anode of the first diode, the cathode of the first diode is used to receive the power supply voltage, and the anode of the first diode is the output terminal of the first voltage detection unit.

8. The power supply circuit according to claim 7, characterized in that, The first voltage detection unit further includes a first resistor, a first capacitor, a second resistor, a third resistor, a fourth resistor, a Zener diode, a fifth resistor, a sixth resistor, a seventh resistor, and a second capacitor; One end of the first resistor is connected to the first control unit. The other end of the first resistor is connected to one end of the first capacitor, one end of the second resistor, and the control terminal of the fifth switch. The other ends of the first capacitor, the second resistor, and the fifth switch are all grounded. The first end of the fifth switch is connected to one end of the third resistor. The other end of the third resistor is connected to the control terminal of the sixth switch, one end of the fourth resistor, and the positive terminal of the Zener diode. The other end of the fourth resistor and the negative terminal of the Zener diode are connected to the first end of the sixth switch. The first end of the sixth switch is the detection terminal of the first voltage detection unit. The second end of the sixth switch is connected to one end of the fifth resistor. The other end of the fifth resistor is connected to one end of the sixth resistor and one end of the seventh resistor. One end of the second capacitor and the other end of the sixth resistor are both grounded. The other end of the seventh resistor and the other end of the second capacitor are connected to the positive terminal of the first diode.

9. The power supply circuit according to claim 6, characterized in that, The second voltage detection unit includes an eighth resistor, a ninth resistor, a tenth resistor, a third capacitor, and a second diode; One end of the eighth resistor is the detection terminal of the second voltage detection unit. The other end of the eighth resistor is connected to one end of the ninth resistor and one end of the tenth resistor. One end of the third capacitor and the other end of the ninth resistor are both grounded. The other end of the tenth resistor and the other end of the third capacitor are respectively connected to the positive terminal of the second diode. The negative terminal of the second diode is used to connect to the power supply voltage. The positive terminal of the second diode is the output terminal of the second voltage detection unit.

10. The power supply circuit according to claim 3, characterized in that, The second battery module also includes an inductor current acquisition unit, which includes a current sampler, an eleventh resistor, a third diode, and a fourth capacitor. The first detection terminal of the current sampler is connected to one end of the inductor, the second detection terminal of the current sampler is connected to the other end of the inductor, the output terminal of the current sampler is connected to one end of the eleventh resistor, the other end of the eleventh resistor is connected to the positive terminal of the third diode and one end of the fourth capacitor, the negative terminal of the third diode is used to receive the power supply voltage, the other end of the fourth capacitor is grounded, and the positive terminal of the third diode is connected to the first control unit.

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