Battery equalization circuit and charge-discharge circuit

Abstract

This application belongs to the field of electronic circuit technology and provides a battery balancing circuit and a charging / discharging circuit. The battery balancing circuit includes a voltage acquisition module, a control module, and a charge balancing module. The control module is connected to both the voltage acquisition module and the charge balancing module. The voltage acquisition module is connected to the positive terminal and series node of a first battery, and the charge balancing module is connected to the positive terminal and series node of the first battery, and the negative terminal of a second battery. The voltage acquisition module acquires the voltage of the two batteries in real time. The control module monitors the voltage difference between the two batteries. When the voltage difference exceeds a first threshold, it outputs a first signal, instructing the charge balancing module to discharge the target battery. During the discharge of the target battery, the voltage difference is continuously monitored. When the voltage difference falls below a second threshold, it outputs a second signal, instructing the charge balancing module to stop discharging the target battery, thus maintaining voltage balance between the two batteries during charging and discharging and avoiding the problem of insufficient battery performance due to voltage imbalance.

Description

Technical Field

[0001] This application belongs to the field of electronic circuit technology, and in particular relates to a battery balancing circuit and a charging and discharging circuit. Background Technology

[0002] In battery series applications, there is a problem where, when the voltage difference between two batteries is too large, the system uses the battery with the lower voltage as the condition for stopping discharge and the battery with the higher voltage as the condition for stopping charging, resulting in the battery performance not being fully utilized. Utility Model Content

[0003] This application provides a battery balancing circuit and a charging / discharging circuit, which can solve the problem that battery performance cannot be fully utilized due to uneven battery voltage in battery series applications.

[0004] In a first aspect, embodiments of this application provide a battery balancing circuit, including a voltage acquisition module, a control module, and a power balancing module; the control module is connected to the voltage acquisition module and the power balancing module respectively; the voltage acquisition module is used to connect to the positive terminal and the series node of a first battery respectively; the power balancing module is used to connect to the positive terminal of the first battery, the series node, and the negative terminal of a second battery respectively; the series node is the common connection terminal of the first battery and the second battery.

[0005] The voltage acquisition module is used to acquire the voltages of the first battery and the second battery to obtain a first voltage and a second voltage. The control module is used to compare the first voltage and the second voltage. If the voltage difference between the first voltage and the second voltage is greater than a first threshold, a first signal is output. The first signal is used to instruct the power balancing module to discharge the target battery. During the discharge of the target battery, if the voltage difference between the first voltage and the second voltage is less than a second threshold, a second signal is output. The second signal is used to instruct the power balancing module to stop discharging the target battery. The target battery is the battery with the higher voltage between the first battery and the second battery.

[0006] In one possible implementation of the first aspect, the power balancing module includes a logic unit, a first switching unit, a second switching unit, and a resistor unit; the input terminal of the logic unit is connected to the control module, the first output terminal of the logic unit is connected to the control terminal of the first switching unit, the second output terminal of the logic unit is connected to the control terminal of the second switching unit, the first terminal of the first switching unit is used to connect to the positive terminal of the first battery, the second terminal of the first switching unit is connected to the first terminal of the resistor unit and the first terminal of the second switching unit respectively, the second terminal of the resistor unit is used to connect to the series node, and the second terminal of the second switching unit is used to connect to the negative terminal of the second battery.

[0007] The logic unit is configured to receive a first signal and output a first logic signal and a second logic signal based on the first signal; the logic unit is also configured to receive a second signal and output a third logic signal and a fourth logic signal based on the second signal.

[0008] When the target battery is the first battery, the second switching unit is used to disconnect according to the second logic signal, and the first switching unit is used to turn on according to the first logic signal, so that the first battery discharges through the resistor unit; the second switching unit is also used to disconnect according to the fourth logic signal, and the first switching unit is also used to disconnect according to the third logic signal, so that the first battery stops discharging.

[0009] When the target battery is the second battery, the first switching unit is used to disconnect according to the first logic signal, and the second switching unit is used to turn on according to the second logic signal, so that the second battery discharges through the resistor unit; the first switching unit is also used to disconnect according to the third logic signal, and the second switching unit is also used to disconnect according to the fourth logic signal, so that the second battery stops discharging.

[0010] In one possible implementation of the first aspect, the logic unit includes a logic chip, a first resistor, and a second resistor. A first terminal of both the first resistor and the second resistor receives a first power supply voltage. A second terminal of the first resistor is connected to a fifth pin of the logic chip and the control module. A second terminal of the second resistor is connected to a second pin of the logic chip and the control module. A sixth pin of the logic chip is connected to a control terminal of the second switching unit and a first pin of the logic chip. A fourth pin of the logic chip is connected to a control terminal of the first switching unit and a third pin of the logic chip. An eighth pin of the logic chip receives a second power supply voltage, and a seventh pin of the logic chip is grounded.

[0011] In one possible implementation of the first aspect, the first switching unit includes a first switching transistor, a second switching transistor, a third resistor, and a fourth resistor. The first end of the third resistor and the first end of the second switching transistor are both connected to the positive terminal of the first battery. The second end of the third resistor is connected to the first end of the fourth resistor and the control terminal of the second switching transistor, respectively. The second end of the second switching transistor is connected to the first end of the second switching unit and the first end of the resistor unit, respectively. The second end of the fourth resistor is connected to the first end of the first switching transistor. The control terminal of the first switching transistor is connected to the first output terminal of the logic unit. The second end of the first switching transistor is grounded.

[0012] In one possible implementation of the first aspect, the second switching unit includes a third switching transistor, a fourth switching transistor, a fifth resistor, and a sixth resistor. The first terminal of the fifth resistor is connected to the first terminal of the fourth switching transistor, the first terminal of the resistor unit, and the second terminal of the first switching unit. The second terminal of the fifth resistor is connected to the control terminal of the fourth switching transistor and the first terminal of the sixth resistor. The second terminal of the fourth switching transistor is used to connect to the negative terminal of the second battery. The second terminal of the sixth resistor is connected to the first terminal of the third switching transistor. The control terminal of the third switching transistor is connected to the second output terminal of the logic unit. The second terminal of the third switching transistor is grounded.

[0013] In one possible implementation of the first aspect, the resistor unit includes a seventh resistor, the first end of which is connected to the second end of the first switching unit and the first end of the second switching unit, respectively, and the second end of the seventh resistor is used to connect to the series node.

[0014] In one possible implementation of the first aspect, the voltage acquisition module includes a first voltage acquisition unit and a second voltage acquisition unit, wherein the first voltage acquisition unit is connected to the positive terminal of the first battery and the control module, and the second voltage acquisition unit is connected to the series node and the control module.

[0015] The first voltage acquisition unit is used to acquire the voltage of the first battery, obtain a first voltage, and transmit the first voltage to the control module; the second voltage acquisition unit is used to acquire the voltage of the second battery, obtain a second voltage, and transmit the second voltage to the control module.

[0016] In one possible implementation of the first aspect, the first voltage acquisition unit includes an eighth resistor and a ninth resistor, the first end of the eighth resistor is connected to the positive terminal of the first battery, the second end of the eighth resistor is connected to the first end of the ninth resistor and the control module, and the second end of the ninth resistor is grounded.

[0017] In one possible implementation of the first aspect, the second voltage acquisition unit includes a tenth resistor and an eleventh resistor, the first end of the tenth resistor is used to connect to the series node, the second end of the tenth resistor is connected to the first end of the eleventh resistor and the control module respectively, and the second end of the eleventh resistor is grounded.

[0018] Secondly, embodiments of this application provide a charging and discharging circuit, including the battery balancing circuit described in any one of the first aspects.

[0019] The beneficial effects of the embodiments in this application compared with the prior art are:

[0020] This application provides a battery balancing circuit, including a voltage acquisition module, a control module, and a power balancing module. The control module is connected to both the voltage acquisition module and the power balancing module. The voltage acquisition module is used to connect to the positive terminal and the series node of a first battery. The power balancing module is used to connect to the positive terminal and the series node of the first battery, and the negative terminal of a second battery. The series node is the common connection terminal of the first battery and the second battery.

[0021] The voltage acquisition module is used to acquire the voltages of the first battery and the second battery to obtain the first voltage and the second voltage. The control module is used to compare the first voltage and the second voltage. If the voltage difference between the first voltage and the second voltage is greater than a first threshold, a first signal is output. The first signal is used to instruct the power balancing module to discharge the target battery. During the discharge process of the target battery, if the voltage difference between the first voltage and the second voltage is less than the second threshold, a second signal is output. The second signal is used to instruct the power balancing module to stop discharging the target battery. The target battery is the battery with the higher voltage among the first battery and the second battery.

[0022] This application uses a voltage acquisition module to collect the voltages of a first battery and a second battery in real time, and transmits the collected first and second voltages to a control module. The control module compares the first and second voltages. When the voltage difference between the first and second voltages is greater than a first threshold, it indicates that the first and second batteries have a voltage imbalance. At this time, a first signal is output, instructing the power balancing module to discharge the battery with the higher voltage to balance the voltage between the two batteries. During the discharge of the battery with the higher voltage, the control module continuously compares the first and second voltages. When the voltage difference between the first and second voltages is less than a second threshold, it indicates that the voltages of the first and second batteries have been balanced. At this time, a second signal is output, instructing the power balancing module to stop discharging the battery with the higher voltage. Through the above process, the two batteries can reach full charge simultaneously during charging to fully utilize their capacity; during discharging, they can discharge synchronously to the cutoff voltage to fully utilize their power, thereby avoiding the problem of insufficient battery performance due to voltage imbalance.

[0023] It is understandable that the beneficial effects of the second aspect mentioned above can be found in the relevant descriptions in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the 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.

[0025] Figure 1 This is a schematic block diagram of a battery balancing circuit provided in one embodiment of this application;

[0026] Figure 2 This is a schematic block diagram of a battery balancing circuit provided in another embodiment of this application;

[0027] Figure 3 This is a circuit connection diagram of a battery balancing circuit provided in an embodiment of this application;

[0028] Figure 4 This is a circuit connection diagram of a battery balancing circuit provided in another embodiment of this application;

[0029] Figure 5 This is a schematic block diagram of a battery balancing circuit provided in another embodiment of this application;

[0030] Figure 6 This is a circuit connection diagram of a battery balancing circuit provided in another embodiment of this application;

[0031] Figure 7This is a circuit connection diagram of a battery balancing circuit provided in another embodiment of this application.

[0032] In the diagram: 10, voltage acquisition module; 11, first voltage acquisition unit; 12, second voltage acquisition unit; 20, control module; 30, power balancing module; 31, logic unit; 32, first switch unit; 33, second switch unit; 34, resistor unit; 40, first battery; 50, second battery. Detailed Implementation

[0033] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0034] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0035] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if [the described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [the described condition or event] is detected," or "in response to detection of [the described condition or event]."

[0036] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0037] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0038] To address the issue of insufficient battery performance due to voltage imbalance in series-connected battery applications, embodiments of this application provide a battery balancing circuit, such as... Figure 1 As shown, the battery balancing circuit includes a voltage acquisition module 10, a control module 20, and a power balancing module 30. The control module 20 is connected to the voltage acquisition module 10 and the power balancing module 30 respectively. The voltage acquisition module 10 is used to connect to the positive terminal of the first battery 40 and the series node Node respectively. The power balancing module 30 is used to connect to the positive terminal of the first battery 40, the series node Node, and the negative terminal of the second battery 50 respectively. The series node Node is the common connection terminal of the first battery 40 and the second battery 50.

[0039] Specifically, the voltage acquisition module 10 is used to acquire the voltages of the first battery 40 and the second battery 50 to obtain a first voltage and a second voltage. The control module 20 is used to compare the first voltage and the second voltage. If the voltage difference between the first voltage and the second voltage is greater than a first threshold, a first signal is output. The first signal is used to instruct the power balancing module 30 to discharge the target battery. During the discharge process of the target battery, if the voltage difference between the first voltage and the second voltage is less than the second threshold, a second signal is output. The second signal is used to instruct the power balancing module 30 to stop discharging the target battery. The target battery is the battery with the higher voltage among the first battery 40 and the second battery 50. The first signal includes a first sub-signal and a second sub-signal. The second signal includes a third sub-signal and a fourth sub-signal. In this embodiment, the first threshold is 1V, and the second threshold is 0.2V. The values ​​of the first threshold and the second threshold can be adjusted according to actual conditions.

[0040] This application uses a voltage acquisition module 10 to acquire the voltages of the first battery 40 and the second battery 50 in real time, and transmits the acquired first and second voltages to a control module 20. The control module 20 compares the first and second voltages. When the voltage difference between the first and second voltages is greater than a first threshold, it indicates that the first battery 40 and the second battery 50 have a voltage imbalance. At this time, it outputs a first signal to instruct the power balancing module 30 to discharge the battery with the higher voltage to balance the voltage between the two batteries. During the discharge of the battery with the higher voltage, the control module 20 continuously compares the first and second voltages. When the voltage difference between the first and second voltages is less than a second threshold, it indicates that the voltages of the first battery 40 and the second battery 50 have been balanced. At this time, it outputs a second signal to instruct the power balancing module 30 to stop discharging the battery with the higher voltage. Through the above process, the two batteries can reach full charge simultaneously during charging to fully utilize their capacity; during discharging, they can discharge synchronously to the cutoff voltage to fully utilize their power, thereby avoiding the problem of insufficient battery performance due to voltage imbalance.

[0041] In some embodiments, such as Figure 2 As shown, the power balancing module 30 includes a logic unit 31, a first switch unit 32, a second switch unit 33, and a resistor unit 34. The input terminal of the logic unit 31 is connected to the control module 20, the first output terminal of the logic unit 31 is connected to the control terminal of the first switch unit 32, and the second output terminal of the logic unit 31 is connected to the control terminal of the second switch unit 33. The first terminal of the first switch unit 32 is used to connect to the positive terminal of the first battery 40, and the second terminal of the first switch unit 32 is connected to the first terminal of the resistor unit 34 and the first terminal of the second switch unit 33, respectively. The second terminal of the resistor unit 34 is used to connect to the series node Node, and the second terminal of the second switch unit 33 is used to connect to the negative terminal of the second battery 50.

[0042] Specifically, the control module 20 compares the first voltage and the second voltage. If the voltage difference between the first voltage and the second voltage is greater than a first threshold, it outputs a first signal. The logic unit 31 receives the first signal and outputs a first logic signal and a second logic signal based on the first signal. When the target battery is the first battery 40, the second switch unit 33 is turned off according to the second logic signal, and the first switch unit 32 is turned on according to the first logic signal, allowing the first battery 40 to discharge through the resistor unit 43 to balance the voltage between the two batteries. During the discharge of the first battery 40, the control module 20 continuously compares the first voltage and the second voltage. When the voltage difference between the first voltage and the second voltage is less than the second threshold, it indicates that the voltage of the first battery and the second battery has been balanced, and at this time, a second signal is output. The logic unit 31 also receives the second signal and outputs a third logic signal and a fourth logic signal based on the second signal. The second switch unit 33 is also turned off according to the fourth logic signal, and the first switch unit 32 is also turned off according to the third logic signal, stopping the first battery 40 from discharging.

[0043] When the target battery is the second battery 50, the first switching unit 32 is used to disconnect according to the first logic signal, and the second switching unit 33 is used to turn on according to the second logic signal, allowing the second battery 50 to discharge through the resistor unit 34. During the discharge of the second battery 50, if the voltages of the first battery 40 and the second battery 50 are equalized, the control module 20 outputs a second signal. The logic unit 31 is also used to output a third logic signal and a fourth logic signal according to the second signal. The first switching unit 32 is also used to disconnect according to the third logic signal, and the second switching unit 33 is also used to disconnect according to the fourth logic signal, stopping the discharge of the second battery 50.

[0044] In some embodiments, such as Figure 3 As shown, logic unit 31 includes logic chips (U2A and U2B), a first resistor R1, and a second resistor R2. The first terminals of both resistors R1 and R2 receive a first power supply voltage VCC. The second terminal of R1 is connected to the fifth pin 5 of the logic chip and the control module 20. The second terminal of R2 is connected to the second pin 2 of the logic chip and the control module 20. The sixth pin 6 of the logic chip is connected to the control terminal of the second switching unit 33 and the first pin 1 of the logic chip. The fourth pin 4 of the logic chip is connected to the control terminal of the first switching unit 32 and the third pin 3 of the logic chip. The eighth pin 8 of the logic chip receives a second power supply voltage VCC_5V, and the seventh pin 7 of the logic chip is grounded. The fourth pin 4 of the logic chip serves as the first output terminal of logic unit 31, and the first pin 1 of the logic chip serves as the second output terminal of logic unit 31.

[0045] Specifically, the voltage acquisition module 10 acquires the voltages of the first battery 40 and the second battery 50 to obtain a first voltage and a second voltage. The control module 20 compares the first voltage and the second voltage. When the voltage difference between the first voltage and the second voltage is greater than a first threshold, it outputs a first signal. Assuming the control module 20 detects that the voltage of the first battery 40 is greater than the voltage of the second battery 50, the first sub-signal in the first signal will pull the fifth pin 5 of the logic chip low, and the second sub-signal in the second signal will keep the second pin 2 of the logic chip high. Therefore, the fourth pin 4 of the logic chip outputs a high level, and the first pin 1 of the logic chip outputs a low level. At this time, the first logic signal is high, and the second logic signal is low. The second logic signal controls the second switching unit 33 to open. The first logic signal controls the first switching unit 32 to open, allowing the first battery 40 to discharge through the resistor unit 34. When the voltages of the first battery 40 and the second battery 50 reach equilibrium, the control module 20 outputs the second signal. The third sub-signal in the second signal will turn the fifth pin 5 of the logic chip high, and the fourth sub-signal in the second signal will keep the second pin 2 of the logic chip high. Therefore, the fourth pin 4 of the logic chip outputs a low level, and the first pin 1 of the logic chip outputs a low level. At this time, the third logic signal is low, and the fourth logic signal is low. The fourth logic signal still controls the second switching unit 33 to open, and the third logic signal controls the first switching unit 32 to open. Therefore, the first battery 40 stops discharging.

[0046] Assuming the control module 20 detects that the voltage of the second battery 50 is greater than the voltage of the first battery 40, the second sub-signal in the first signal will pull the second pin 2 of the logic chip low, and the first sub-signal in the second signal will keep the fifth pin 5 of the logic chip high. Therefore, the first pin 1 of the logic chip outputs a high level, and the fourth pin 4 of the logic chip outputs a low level. At this time, the first logic signal is low, and the second logic signal is high. The first logic signal controls the first switching unit 32 to open. The second logic signal controls the second switching unit 33 to open, allowing the second battery 50 to discharge through the resistor unit 34. When the voltages of the first battery 40 and the second battery 50 reach equilibrium, the control module 20 outputs the second signal. The fourth sub-signal in the second signal will turn the second pin 2 of the logic chip high, and the third sub-signal in the second signal will keep the fifth pin 5 of the logic chip high. Therefore, the first pin 1 of the logic chip outputs a low level, and the fourth pin 4 of the logic chip outputs a low level. At this time, the third logic signal is low, and the fourth logic signal is low. The third logic signal still controls the first switch unit 32 to open, and the fourth logic signal controls the second switch unit 33 to open. Therefore, the second battery 50 stops discharging.

[0047] In some embodiments, such as Figure 3As shown, the first switching unit 32 includes a first switching transistor M1, a second switching transistor M2, a third resistor R3, and a fourth resistor R4. The first end of the third resistor R3 and the first end of the second switching transistor M2 are both connected to the positive terminal of the first battery 40. The second end of the third resistor R3 is connected to the first end of the fourth resistor R4 and the control terminal of the second switching transistor M2, respectively. The second end of the second switching transistor M2 is connected to the first end of the second switching unit 33 and the first end of the resistor unit 34, respectively. The second end of the fourth resistor R4 is connected to the first end of the first switching transistor M1. The control terminal of the first switching transistor M1 is connected to the first output terminal of the logic unit 31, and the second end of the first switching transistor M1 is grounded. Specifically, the control terminal of the first switching transistor M1 serves as the control terminal of the first switching unit 32, the first end of the second switching transistor M2 serves as the first terminal of the first switching unit 32, and the second end of the second switching transistor M2 serves as the second terminal of the first switching unit 32. In this embodiment, the first switch M1 is an NPN transistor, with its control terminal being the base, its first terminal being the collector, and its second terminal being the emitter. The second switch M2 is a PMOS (Positive Channel Metal-Oxide-Semiconductor) transistor, with its control terminal being the gate, its first terminal being the source, and its second terminal being the drain.

[0048] Specifically, the voltage acquisition module 10 acquires the voltages of the first battery 40 and the second battery 50 to obtain a first voltage and a second voltage. The control module 20 compares the first voltage and the second voltage. When the voltage difference between the first voltage and the second voltage is greater than a first threshold, it outputs a first signal. Assuming that the control module 20 detects that the voltage of the first battery 40 is greater than the voltage of the second battery 50, the first sub-signal in the first signal will pull down the fifth pin 5 of the logic chip, and the second sub-signal in the second signal will keep the second pin 2 of the logic chip high. Therefore, the fourth pin 4 of the logic chip outputs a high level, and the first pin 1 of the logic chip outputs a low level. At this time, the first logic signal is high and the second logic signal is low. The second logic signal controls the second switching unit 33 to turn off. The first logic signal controls the first switching transistor M1 to turn on. After the first switching transistor M1 turns on, the voltage division of the third resistor R3 and the fourth resistor R4 controls the second switching transistor M2 to turn on, allowing the first battery 40 to discharge through the resistor unit 34. When the voltages of the first battery 40 and the second battery 50 reach equilibrium, the control module 20 outputs the second signal. The third sub-signal in the second signal will turn the fifth pin 5 of the logic chip high, and the fourth sub-signal in the second signal will keep the second pin 2 of the logic chip high. Therefore, the fourth pin 4 of the logic chip outputs a low level, and the first pin 1 of the logic chip outputs a low level. At this time, the third logic signal is low, and the fourth logic signal is low. The fourth logic signal still controls the second switching unit 33 to turn off, and the third logic signal controls the first switching transistor M1 to turn off. After the first switching transistor M1 turns off, the second switching transistor M2 also turns off. Therefore, the first battery 40 stops discharging.

[0049] For example, such as Figure 4 As shown, the first switching unit 32 also includes a twelfth resistor R12 and a thirteenth resistor R13. The first end of the twelfth resistor R12 is connected to the first end of the thirteenth resistor R13 and the control terminal of the first switching transistor M1, respectively. The second end of the twelfth resistor R12 is connected to the first output terminal of the logic unit 31, and the second end of the thirteenth resistor R13 is grounded.

[0050] Specifically, the thirteenth resistor R13 is used to ensure that the control terminal of the first switch M1 is pulled low when the logic unit 31 does not output a signal, so as to prevent the first switch M1 from being mistakenly turned on. The twelfth resistor R12 is used for current limiting.

[0051] In some embodiments, such as Figure 3As shown, the second switching unit 33 includes a third switching transistor M3, a fourth switching transistor M4, a fifth resistor R5, and a sixth resistor R6. The first end of the fifth resistor R5 is connected to the first end of the fourth switching transistor M4, the first end of the resistor unit 34, and the second end of the first switching unit 32. The second end of the fifth resistor R5 is connected to the control terminal of the fourth switching transistor M4 and the first end of the sixth resistor R6. The second end of the fourth switching transistor M4 is used to connect to the negative terminal of the second battery 50. The second end of the sixth resistor R6 is connected to the first end of the third switching transistor M3. The control terminal of the third switching transistor M3 is connected to the second output terminal of the logic unit 31, and the second end of the third switching transistor M3 is grounded. The control terminal of the third switching transistor M3 serves as the control terminal of the second switching unit 33, the first end of the fourth switching transistor M4 serves as the first end of the second switching unit 33, and the second end of the fourth switching transistor M4 serves as the second end of the second switching unit 33. In this embodiment, the third switch M3 is an NPN transistor, with its control terminal being the base, its first terminal being the collector, and its second terminal being the emitter. The fourth switch M4 is a PMOS transistor, with its control terminal being the gate, its first terminal being the source, and its second terminal being the drain.

[0052] Specifically, the voltage acquisition module 10 acquires the voltages of the first battery 40 and the second battery 50 to obtain a first voltage and a second voltage. The control module 20 compares the first voltage and the second voltage. When the voltage difference between the first voltage and the second voltage is greater than a first threshold, it outputs a first signal. Assuming that the control module 20 detects that the voltage of the second battery 50 is greater than the voltage of the first battery 40, the second sub-signal in the first signal will pull the second pin 2 of the logic chip low, and the first sub-signal in the second signal will keep the fifth pin 5 of the logic chip high. Therefore, the first pin 1 of the logic chip outputs a high level, and the fourth pin 4 of the logic chip outputs a low level. At this time, the first logic signal is low and the second logic signal is high. The first logic signal controls the first switch M1 to turn off. After the first switch M1 turns off, the second switch M2 also turns off. The second logic signal controls the third switch M3 to turn on. After the third switch M3 turns on, the voltage division of the fifth resistor R5 and the sixth resistor R6 controls the fourth switch M4 to turn on, allowing the second battery 50 to discharge through the resistor unit 34. When the voltages of the first battery 40 and the second battery 50 reach equilibrium, the control module 20 outputs a second signal. The fourth sub-signal in the second signal sets the second pin 2 of the logic chip to a high level, and the third sub-signal keeps the fifth pin 5 of the logic chip high. Therefore, the first pin 1 of the logic chip outputs a low level, and the fourth pin 4 of the logic chip outputs a low level. At this time, both the third and fourth logic signals are low. The third logic signal still controls the first switch M1 to turn off. After the first switch M1 turns off, the second switch M2 also turns off. The fourth logic signal controls the third switch M3 to turn off. After the third switch M3 turns off, the fourth switch M4 also turns off. Therefore, the second battery 50 stops discharging.

[0053] For example, such as Figure 4 As shown, the second switching unit 33 also includes a fourteenth resistor R14 and a fifteenth resistor R15. The first end of the fourteenth resistor R14 is connected to the first end of the fifteenth resistor R15 and the control terminal of the third switching transistor M3, respectively. The second end of the fifteenth resistor R15 is connected to the second output terminal of the logic unit 31, and the second end of the fourteenth resistor R14 is grounded.

[0054] Specifically, the fourteenth resistor R14 is used to ensure that the control terminal of the third switch M3 is pulled low when the logic unit 31 does not output a signal, so as to prevent the third switch M3 from being mistakenly turned on. The fifteenth resistor R15 is used for current limiting.

[0055] In some embodiments, such as Figure 3As shown, the resistor unit 34 includes a seventh resistor R7. The first end of the seventh resistor R7 is connected to the second end of the first switch unit 32 and the first end of the second switch unit 33, respectively. The second end of the seventh resistor R7 is used to connect to the series node Node. Specifically, one end of the seventh resistor R7 serves as the first end of the resistor unit 34, and the second end of the seventh resistor R7 serves as the second end of the resistor unit 34.

[0056] Specifically, the voltage acquisition module 10 acquires the voltages of the first battery 40 and the second battery 50 to obtain a first voltage and a second voltage. The control module 20 compares the first voltage and the second voltage. When the voltage difference between the first voltage and the second voltage is greater than a first threshold, it outputs a first signal. Assuming that the control module 20 detects that the voltage of the first battery 40 is greater than the voltage of the second battery 50, the first sub-signal in the first signal will pull the fifth pin 5 of the logic chip low, and the second sub-signal in the second signal will keep the second pin 2 of the logic chip high. Therefore, the fourth pin 4 of the logic chip outputs a high level, and the first pin 1 of the logic chip outputs a low level. At this time, the first logic signal is high and the second logic signal is low. The second logic signal controls the third switch M3 to turn off. After the third switch M3 turns off, the fourth switch M4 also turns off. The first logic signal controls the first switch M1 to turn on. After the first switch M1 turns on, the voltage divider between the third resistor R3 and the fourth resistor R4 controls the second switch M2 to turn on, causing the first battery 40 to discharge through the seventh resistor R7. The discharge current flows from the positive terminal of the first battery 40 through the seventh resistor R7 to the series node Node. When the voltages of the first battery 40 and the second battery 50 reach equilibrium, the control module 20 outputs the second signal. The third sub-signal in the second signal will make the fifth pin 5 of the logic chip high, and the fourth sub-signal in the second signal will keep the second pin 2 of the logic chip high. Therefore, the fourth pin 4 of the logic chip outputs a low level, and the first pin 1 of the logic chip outputs a low level. At this time, the third logic signal is low, and the fourth logic signal is low. The fourth logic signal still controls the third switch M3 to turn off. After the third switch M3 turns off, the fourth switch M4 also turns off. The third logic signal controls the first switch M1 to turn off. After the first switch M1 turns off, the second switch M2 also turns off. Therefore, the first battery 40 stops discharging.

[0057] In some embodiments, such as Figure 5 As shown, the voltage acquisition module 10 includes a first voltage acquisition unit 11 and a second voltage acquisition unit 12. The first voltage acquisition unit 11 is connected to the positive terminal of the first battery 40 and the control module 20, respectively. The second voltage acquisition unit 12 is connected to the series node and the control module 20, respectively.

[0058] Specifically, the first voltage acquisition unit 11 is used to acquire the voltage of the first battery 40, obtain a first voltage, and transmit the first voltage to the control module 20. The second voltage acquisition unit 12 is used to acquire the voltage of the second battery 50, obtain a second voltage, and transmit the second voltage to the control module 20.

[0059] In some embodiments, such as Figure 6 As shown, the first voltage acquisition unit 11 includes an eighth resistor R8 and a ninth resistor R9. The first end of the eighth resistor R8 is connected to the positive terminal of the first battery 40, and the second end of the eighth resistor R8 is connected to both the first end of the ninth resistor R9 and the control module 20. The second end of the ninth resistor R9 is grounded. Specifically, the eighth resistor R8 and the ninth resistor R9 divide the voltage of the first battery 40 to obtain a first voltage, and then transmit the first voltage to the control module 20.

[0060] For example, such as Figure 7 As shown, the first voltage acquisition unit 11 also includes a sixteenth resistor R16 and a first capacitor C1. The first end of the sixteenth resistor R16 is connected to the second end of the eighth resistor R8, and the second end of the sixteenth resistor R16 is connected to both the first end of the first capacitor C1 and the control module 20. The second end of the first capacitor C1 is grounded. Specifically, the sixteenth resistor R16 and the first capacitor C1 are used to filter the first voltage to keep it stable.

[0061] In some embodiments, such as Figure 6 As shown, the second voltage acquisition unit 12 includes a tenth resistor R10 and an eleventh resistor R11. The first end of the tenth resistor R10 is connected to the series node Node, and the second end of the tenth resistor R10 is connected to the first end of the eleventh resistor R11 and the control module 20, respectively. The second end of the eleventh resistor R11 is grounded. Specifically, the tenth resistor R10 and the eleventh resistor R11 divide the voltage of the second battery 50 to obtain a second voltage, and transmit the second voltage to the control module 20.

[0062] For example, such as Figure 7 As shown, the second voltage acquisition unit 12 also includes a seventeenth resistor R17 and a second capacitor C2. The first end of the seventeenth resistor R17 is connected to the second end of the tenth resistor R10, and the second end of the seventeenth resistor R17 is connected to both the first end of the second capacitor C2 and the control module 20. The second end of the second capacitor C2 is grounded. Specifically, the seventeenth resistor R17 and the second capacitor C2 are used to filter the second voltage to keep it stable.

[0063] In some embodiments, the control module 20 may employ an MCU (Microcontroller Unit) to implement the comparison function of the first voltage and the second voltage. The first voltage and the second voltage are received through two I / O (Input / Output) pins of the MCU, compared, and then the first signal or the second signal is output through another two I / O pins of the MCU.

[0064] The control module 20 can also employ a comparison circuit to implement the comparison function of the first voltage and the second voltage, specifically including a voltage differential unit and a comparison unit. The first voltage and the second voltage are converted into differential voltages through the voltage differential unit. The comparison unit outputs a first signal or a second signal based on the differential voltage; specifically, it outputs a first signal when the differential voltage is greater than a first threshold, and outputs a second signal when the differential voltage is less than a second threshold. The comparison unit includes a hysteresis comparator and logic devices, etc. The voltage differential unit can use an operational amplifier to implement the differential function or a differential circuit to implement the differential function.

[0065] In summary, this application uses a voltage acquisition module 10 to collect the voltages of the first battery 40 and the second battery 50 in real time, and transmits the collected first and second voltages to the control module 20. The control module 20 compares the first and second voltages. When the voltage difference between the first and second voltages is greater than a first threshold, it indicates that the first battery 40 and the second battery 50 have a voltage imbalance. At this time, the control module 20 outputs a first signal to instruct the power balancing module 30 to discharge the battery with the higher voltage to balance the voltage between the two batteries. During the discharge of the battery with the higher voltage, the control module 20 continuously compares the first and second voltages. When the voltage difference between the first and second voltages is less than a second threshold, it indicates that the voltages of the first battery 40 and the second battery 50 have been balanced. At this time, the control module 20 outputs a second signal to instruct the power balancing module 30 to stop discharging the battery with the higher voltage. Through the above process, the two batteries can reach full charge simultaneously during charging to fully utilize their capacity; during discharging, they can discharge synchronously to the cutoff voltage to fully utilize their power, thereby avoiding the problem of insufficient battery performance due to voltage imbalance.

[0066] This application also provides a charging and discharging circuit, including the battery balancing circuit described above. Since the charging and discharging circuit provided in this application adopts all the technical solutions of all the above embodiments, it possesses at least all the beneficial effects brought about by the technical solutions of the above embodiments, and will not be elaborated upon further here.

[0067] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A battery balancing circuit, characterized in that, It includes a voltage acquisition module, a control module, and a power balancing module; the control module is connected to the voltage acquisition module and the power balancing module respectively; the voltage acquisition module is used to connect to the positive terminal and the series node of the first battery respectively; the power balancing module is used to connect to the positive terminal of the first battery, the series node, and the negative terminal of the second battery respectively; the series node is the common connection terminal of the first battery and the second battery. The voltage acquisition module is used to acquire the voltages of the first battery and the second battery to obtain a first voltage and a second voltage. The control module is used to compare the first voltage and the second voltage. If the voltage difference between the first voltage and the second voltage is greater than a first threshold, a first signal is output. The first signal is used to instruct the power balancing module to discharge the target battery. During the discharge of the target battery, if the voltage difference between the first voltage and the second voltage is less than a second threshold, a second signal is output. The second signal is used to instruct the power balancing module to stop discharging the target battery. The target battery is the battery with the higher voltage between the first battery and the second battery.

2. The battery balancing circuit according to claim 1, characterized in that, The power balancing module includes a logic unit, a first switch unit, a second switch unit, and a resistor unit. The input terminal of the logic unit is connected to the control module, the first output terminal of the logic unit is connected to the control terminal of the first switch unit, the second output terminal of the logic unit is connected to the control terminal of the second switch unit, the first terminal of the first switch unit is connected to the positive terminal of the first battery, the second terminal of the first switch unit is connected to the first terminal of the resistor unit and the first terminal of the second switch unit, the second terminal of the resistor unit is connected to the series node, and the second terminal of the second switch unit is connected to the negative terminal of the second battery. The logic unit is configured to receive a first signal and output a first logic signal and a second logic signal based on the first signal; the logic unit is also configured to receive a second signal and output a third logic signal and a fourth logic signal based on the second signal. When the target battery is the first battery, the second switching unit is used to disconnect according to the second logic signal, and the first switching unit is used to turn on according to the first logic signal, so that the first battery discharges through the resistor unit; the second switching unit is also used to disconnect according to the fourth logic signal, and the first switching unit is also used to disconnect according to the third logic signal, so that the first battery stops discharging. When the target battery is the second battery, the first switching unit is used to disconnect according to the first logic signal, and the second switching unit is used to turn on according to the second logic signal, so that the second battery discharges through the resistor unit; the first switching unit is also used to disconnect according to the third logic signal, and the second switching unit is also used to disconnect according to the fourth logic signal, so that the second battery stops discharging.

3. The battery balancing circuit according to claim 2, characterized in that, The logic unit includes a logic chip, a first resistor, and a second resistor. The first end of the first resistor and the first end of the second resistor both receive a first power supply voltage. The second end of the first resistor is connected to the fifth pin of the logic chip and the control module, respectively. The second end of the second resistor is connected to the second pin of the logic chip and the control module, respectively. The sixth pin of the logic chip is connected to the control terminal of the second switching unit and the first pin of the logic chip, respectively. The fourth pin of the logic chip is connected to the control terminal of the first switching unit and the third pin of the logic chip, respectively. The eighth pin of the logic chip receives a second power supply voltage, and the seventh pin of the logic chip is grounded.

4. The battery balancing circuit according to claim 2, characterized in that, The first switching unit includes a first switching transistor, a second switching transistor, a third resistor, and a fourth resistor. The first end of the third resistor and the first end of the second switching transistor are both connected to the positive terminal of the first battery. The second end of the third resistor is connected to the first end of the fourth resistor and the control terminal of the second switching transistor, respectively. The second end of the second switching transistor is connected to the first end of the second switching unit and the first end of the resistor unit, respectively. The second end of the fourth resistor is connected to the first end of the first switching transistor. The control terminal of the first switching transistor is connected to the first output terminal of the logic unit. The second end of the first switching transistor is grounded.

5. The battery balancing circuit according to claim 2, characterized in that, The second switching unit includes a third switching transistor, a fourth switching transistor, a fifth resistor, and a sixth resistor. The first end of the fifth resistor is connected to the first end of the fourth switching transistor, the first end of the resistor unit, and the second end of the first switching unit. The second end of the fifth resistor is connected to the control terminal of the fourth switching transistor and the first end of the sixth resistor. The second end of the fourth switching transistor is used to connect to the negative terminal of the second battery. The second end of the sixth resistor is connected to the first end of the third switching transistor. The control terminal of the third switching transistor is connected to the second output terminal of the logic unit. The second end of the third switching transistor is grounded.

6. The battery balancing circuit according to claim 2, characterized in that, The resistor unit includes a seventh resistor, the first end of which is connected to the second end of the first switch unit and the first end of the second switch unit, respectively, and the second end of the seventh resistor is used to connect to the series node.

7. The battery balancing circuit according to claim 1 or 2, characterized in that, The voltage acquisition module includes a first voltage acquisition unit and a second voltage acquisition unit. The first voltage acquisition unit is connected to the positive terminal of the first battery and the control module, respectively. The second voltage acquisition unit is connected to the series node and the control module, respectively. The first voltage acquisition unit is used to acquire the voltage of the first battery, obtain a first voltage, and transmit the first voltage to the control module; The second voltage acquisition unit is used to acquire the voltage of the second battery, obtain the second voltage, and transmit the second voltage to the control module.

8. The battery balancing circuit according to claim 7, characterized in that, The first voltage acquisition unit includes an eighth resistor and a ninth resistor. The first end of the eighth resistor is used to connect to the positive terminal of the first battery. The second end of the eighth resistor is connected to the first end of the ninth resistor and the control module, respectively. The second end of the ninth resistor is grounded.

9. The battery balancing circuit according to claim 7, characterized in that, The second voltage acquisition unit includes a tenth resistor and an eleventh resistor. The first end of the tenth resistor is used to connect to the series node, the second end of the tenth resistor is connected to the first end of the eleventh resistor and the control module, and the second end of the eleventh resistor is grounded.

10. A charging and discharging circuit, characterized in that, Includes the battery equalization circuit as described in any one of claims 1-9.

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