Charging and discharging circuit of battery

Abstract

The embodiment of the invention provides a charging and discharging circuit of a battery, the battery comprises a first battery cell and a second battery cell which are connected in series, and the negative electrode of the first battery cell is electrically connected with the positive electrode of the second battery cell. The charging and discharging circuit comprises an equalization circuit and a voltage conversion circuit, the voltage conversion circuit can convert an input voltage into a first voltage and a second voltage, provide the first voltage to a first battery cell, provide the second voltage to a second battery cell and provide the first voltage and the second voltage to a load in a charging stage, and the equalization circuit can convert the input voltage into the first voltage and the second voltage in a charging and discharging stage. When the voltage difference between the first battery cell voltage and the second battery cell voltage is larger than a first preset voltage, the positive electrode voltage of the discharging battery cell is converted and provided for the charging battery cell until the voltage difference between the first battery cell voltage and the second battery cell voltage is smaller than a second preset voltage, and a first power rail and a second power rail are provided for a load in the discharging stage. The charging and discharging circuit can improve the charging and discharging efficiency of the battery.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to the technical field of integrated circuits, and in particular to a battery charging and discharging circuit. Background Art

[0002] At present, by using dual cells in series as batteries, the battery capacity and charging speed can be improved. Since the internal impedance and discharge rate of the cells are inconsistent, each cell needs to be balanced to a common index during the battery charging and discharging process to extend the battery life and obtain a larger battery capacity.

[0003] In the prior art, the target cell unit is discharged through a resistor to achieve voltage consistency of each cell, so as to realize passive balancing of the battery. However, during the battery charging and discharging process, the resistor in the passive balancing solution will bring more power consumption, and this part of power consumption has no effect, resulting in low charging and discharging efficiency of the battery. Summary of the invention

[0004] The embodiments of the present disclosure provide a battery charging and discharging circuit, which can improve the charging and discharging efficiency of the battery.

[0005] In a first aspect, the present disclosure provides a charge and discharge circuit of a battery, wherein the battery comprises a first battery cell and a second battery cell connected in series, wherein a negative electrode of the first battery cell is electrically connected to a positive electrode of the second battery cell.

[0006] The charging and discharging circuit includes: a balancing circuit and a voltage conversion circuit.

[0007] The voltage conversion circuit is configured to, during the charging stage, convert the input voltage into a first voltage and a second voltage, wherein the first voltage is twice the second voltage, provide the first voltage to the first battery cell, provide the second voltage to the second battery cell, and provide the first voltage and the second voltage to the load. The balancing circuit is configured to, during the charging and discharging stage, obtain the first battery cell voltage and the second battery cell voltage, and when the voltage difference between the first battery cell voltage and the second battery cell voltage is greater than the first preset voltage, convert the positive voltage of the discharging battery cell and provide it to the charging battery cell until the voltage difference between the first battery cell voltage and the second battery cell voltage is less than the second preset voltage; during the discharging stage, provide the first power rail and the second power rail to the load.

[0008] Among them, the discharging cell is the cell with the larger cell voltage between the first cell and the second cell, and the charging cell is the cell with the smaller cell voltage between the first cell and the second cell; the first power rail is the positive electrode voltage of the first cell after equalization, and the second power rail is the positive electrode voltage of the second cell after equalization; the second preset voltage is less than the first preset voltage.

[0009] In some embodiments of the present disclosure, the balancing circuit is further configured to, when the first cell voltage is greater than the sum of the second cell voltage and the first preset voltage, step down the positive voltage of the first cell and provide it to the second cell until the first cell voltage is less than the sum of the second cell voltage and the second preset voltage. When the sum of the first cell voltage and the first preset voltage is less than the second cell voltage, step up the positive voltage of the second cell and provide it to the first cell until the sum of the first cell voltage and the second preset voltage is greater than the second cell voltage.

[0010] In some embodiments of the present disclosure, the balancing circuit includes: a charge pump and a control module, the output end of the control module is electrically connected to the control end of the charge pump, the first end of the charge pump is electrically connected to the positive electrode of the first battery cell, and the second end of the charge pump is electrically connected to the positive electrode of the second battery cell.

[0011] The control module is configured to, when the first cell voltage is greater than the sum of the second cell voltage and the first preset voltage, generate a first control signal until the first cell voltage is less than the sum of the second cell voltage and the second preset voltage, and stop generating the first control signal. When the sum of the first cell voltage and the first preset voltage is less than the second cell voltage, generate a second control signal until the sum of the first cell voltage and the second preset voltage is greater than the second cell voltage, and stop generating the second control signal.

[0012] The charge pump is configured to, under the action of the first control signal, reduce the positive voltage of the first battery cell to half and provide it to the second battery cell. Under the action of the second control signal, increase the positive voltage of the second battery cell to twice and provide it to the first battery cell.

[0013] In some embodiments of the present disclosure, the equalization circuit also includes a voltage detection unit and a voltage comparator, the first input end of the voltage detection unit is electrically connected to the positive electrode of the first battery cell, the second input end of the voltage detection unit is electrically connected to the positive electrode of the second battery cell, the first output end of the voltage detection unit is electrically connected to the first input end of the voltage comparator, the second output end of the voltage detection unit is electrically connected to the second input end of the voltage comparator, and the output end of the voltage comparator is electrically connected to the input end of the control module.

[0014] The voltage detection unit is configured to collect the positive voltage of the first battery cell and the positive voltage of the second battery cell, and determine the first battery cell voltage and the second battery cell voltage based on the positive voltage of the first battery cell and the positive voltage of the second battery cell. The voltage comparator is configured to compare the voltage difference between the first battery cell voltage and the second battery cell voltage with the first preset voltage.

[0015] In some embodiments of the present disclosure, the control module is further configured to stop generating waves to put the balancing circuit in a standby state when the voltage difference between the first battery cell voltage and the second battery cell voltage is less than the second preset voltage.

[0016] In some embodiments of the present disclosure, the balancing circuit further includes an enabling module.

[0017] The enabling module is configured to enable the equalizing circuit when an enabling signal is received, and to prohibit enabling the equalizing circuit when a disabling signal is received.

[0018] In some embodiments of the present disclosure, the balancing circuit further includes a voltage setting module.

[0019] The voltage setting module is configured to set the first preset voltage and the second preset voltage.

[0020] In some embodiments of the present disclosure, the voltage conversion circuit includes: a BUCK circuit and a switched capacitor circuit, the input end of the BUCK circuit is electrically connected to the input voltage and the input end of the switched capacitor circuit, the output end of the BUCK circuit is electrically connected to the positive electrode of the second battery cell, and the output end of the switched capacitor circuit is electrically connected to the positive electrode of the first battery cell.

[0021] In some embodiments of the present disclosure, the charge pump includes: a first transistor, a second transistor, a third transistor, a fourth transistor and a flying capacitor. The first end of the first transistor is electrically connected to the positive electrode of the first battery cell, the second end of the first transistor is electrically connected to the first plate of the flying capacitor and the first end of the second transistor, the second end of the second transistor is electrically connected to the first end of the third transistor and the positive electrode of the second battery cell, the second end of the third transistor is electrically connected to the second plate of the flying capacitor and one end of the fourth transistor, the second end of the fourth transistor is grounded, and the control end of the first transistor, the control end of the second transistor, the control end of the third transistor and the control end of the fourth transistor are electrically connected to the first output end, the second output end, the third output end and the fourth output end of the control module in a one-to-one correspondence.

[0022] The first transistor, the second transistor, the third transistor, the fourth transistor and the control module are integrated in a balancing chip, and the peripheral circuit of the balancing chip includes the flying capacitor.

[0023] In the technical solution of the embodiment of the present disclosure, the charge and discharge circuit of the battery includes an equalization circuit and a voltage conversion circuit. The voltage conversion circuit converts the input voltage into a first voltage and a second voltage during the charging stage, provides the first voltage to the first battery cell, provides the second voltage to the second battery cell, and provides the first voltage and the second voltage to the load. The equalization circuit can obtain the first battery cell voltage and the second battery cell voltage during the charging and discharging stage. When the voltage difference between the first battery cell voltage and the second battery cell voltage is greater than the first preset voltage, the positive electrode voltage of the discharge battery cell is converted and provided to the charging battery cell until the voltage difference between the first battery cell voltage and the second battery cell voltage is less than the second preset voltage; the equalization circuit can also provide the first power rail and the second power rail to the load during the discharging stage. On the one hand, since the first voltage is twice the second voltage, during the charging stage, the charge and discharge circuit can provide different operating voltages to different loads respectively, without the need to step down the charging voltage of the battery, which can reduce unnecessary power consumption during the charging process, thereby improving the charging efficiency of the battery. Secondly, during the charge and discharge phase, the charge and discharge circuit can transfer the power from the battery with more power to the battery with less power, which can avoid unnecessary power consumption and thus improve the charge and discharge efficiency of the battery. Thirdly, during the discharge phase, the charge and discharge circuit can provide different operating voltages to different loads, without the need to step down the discharge voltage of the battery, which can reduce unnecessary power consumption during the discharge process and thus improve the discharge efficiency of the battery.

[0024] The above description is only an overview of the technical solution of the embodiment of the present application. In order to more clearly understand the technical means of the embodiment of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the embodiment of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present application, a brief introduction will be given below to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0026] Figure 1 A structural schematic diagram of a dual-cell battery system provided by the prior art.

[0027] Figure 2A schematic diagram of the structure of a battery charging and discharging circuit provided in an embodiment of the present disclosure.

[0028] Figure 3 A schematic diagram of the structure of another battery charging and discharging circuit provided in an embodiment of the present disclosure.

[0029] Figure 4 A schematic diagram of the structure of an equalization circuit provided in an embodiment of the present disclosure.

[0030] Figure 5 A schematic circuit diagram of the structure of a balancing chip provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without creative work also fall within the scope of protection of the present disclosure.

[0032] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by a person skilled in the art to which the subject matter of the present disclosure belongs. It will be further understood that terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with their meaning in the context of the specification and the relevant art, and will not be interpreted in an idealized or overly formal form unless otherwise explicitly defined herein. As used herein, a statement that two or more parts are "electrically connected" together shall mean that the parts are directly joined together or joined through one or more intermediate components.

[0033] Reference to "embodiments" in this disclosure means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase "embodiments" in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described in this disclosure may be combined with other embodiments.

[0034] In addition, the terms "first", "second", etc. in the specification and claims of the present disclosure or the above-mentioned drawings are used to distinguish different objects rather than to describe a specific order, and may explicitly or implicitly include one or more of the features.

[0035] The term "and / or" in this disclosure is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0036] In the description of the present disclosure, unless otherwise specified, "plurality" and "at least two" mean more than two (including two), and similarly, "multiple groups" and "at least two groups" mean more than two groups (including two).

[0037] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings.

[0038] By sampling dual cells connected in series as a battery, the battery capacity and charging speed can be improved. Figure 1 A schematic diagram of a dual-cell battery system provided by the prior art, such as Figure 1 As shown, the dual-cell battery system 1 includes a battery pack 10, a bidirectional voltage conversion circuit 20, a switch capacitor circuit 30, a BUCK charging circuit 40, an overvoltage protection circuit 50, a load 60 and an adapter 70. Among them, the input end of the overvoltage protection circuit 50 is electrically connected to the output end of the adapter 70, and the output end of the overvoltage protection circuit 50 is electrically connected to the input end of the switch capacitor circuit 30 and the input end of the BUCK charging circuit 40. The first output end of the BUCK charging circuit 40 is electrically connected to the positive electrode of the battery pack 10 through the bidirectional voltage conversion circuit 20, the second output end of the BUCK charging circuit 40 is electrically connected to the load 60, the output end of the switch capacitor circuit 30 is electrically connected to the positive electrode of the battery pack 10, and the negative electrode of the battery pack 10 is grounded.

[0039] The battery pack 10 includes a first battery cell 11 and a second battery cell 12 connected in series, and a battery protection circuit 13. The positive electrode of the first battery cell 11 is electrically connected to the positive power supply terminal VDD of the battery protection circuit 13 through the first resistor R1, the negative electrode of the first battery cell 11 is electrically connected to the positive electrode of the second battery cell 12 and the negative electrode of the first battery cell 11 is electrically connected to the battery protection circuit 13 through the second resistor R2, the negative electrode of the second battery cell 12 is electrically connected to the negative power supply terminal VSS of the battery protection circuit 13 through the third resistor R3, and the negative electrode of the second battery cell 12 is grounded. The positive electrode of the first battery cell 11 is the positive electrode of the battery pack 10, and the negative electrode of the second battery cell 12 is the negative electrode of the battery pack 10.

[0040] Exemplarily, the adapter 70 can provide a power supply voltage to the switched capacitor circuit 30, and the switched capacitor circuit 30 can convert the power supply voltage into a charging voltage required by the battery pack 10 to charge the battery pack 10. The BUCK charging circuit 40 cooperates with the bidirectional voltage conversion circuit 20 to convert the power supply voltage into a charging voltage required by the battery pack 10 to charge the battery pack 10. The BUCK charging circuit 40 can also step down the discharge voltage of the battery pack 10 and provide the stepped-down discharge voltage to the load 60 as a load voltage.

[0041] For example, the load 60 includes a display, a power amplifier, a motor, a low-voltage power management circuit, an application processor, and the like.

[0042] The inherent inconsistency between the first battery cell 11 and the second battery cell 12 will cause the internal impedance and discharge rate of the first battery cell 11 and the second battery cell 12 to be inconsistent. During the charging and discharging process of the battery pack 10, balancing the first battery cell 11 and the second battery cell 12 to a common indicator can help extend the battery life and obtain a larger battery capacity.

[0043] In the prior art, a separate discharge path including a resistor is usually provided for the first battery cell 11 and the second battery cell 12. When the first battery cell 11 and the second battery cell 12 need to be balanced, the discharge path of the balanced battery cell is opened, and the energy of the balanced battery cell can be consumed through the discharge path, thereby realizing passive battery balancing. However, passive balancing brings more power consumption during the charging and discharging process of the battery pack, and this part of the power consumption has no function, resulting in low charging and discharging efficiency of the battery.

[0044] In view of this, the present disclosure provides a battery charging and discharging circuit, including an equalizing circuit and a voltage conversion circuit. The voltage conversion circuit converts the input voltage into a first voltage and a second voltage during the charging stage, provides the first voltage to the first battery cell, provides the second voltage to the second battery cell, and provides the first voltage and the second voltage to the load. The equalizing circuit can obtain the first battery cell voltage and the second battery cell voltage during the charging and discharging stage. When the voltage difference between the first battery cell voltage and the second battery cell voltage is greater than the first preset voltage, the positive electrode voltage of the discharging battery cell is converted and provided to the charging battery cell until the voltage difference between the first battery cell voltage and the second battery cell voltage is less than the second preset voltage; the equalizing circuit can also provide the first power rail and the second power rail to the load during the discharging stage. On the one hand, since the first voltage is twice the second voltage, during the charging stage, the charging and discharging circuit can provide different operating voltages to different loads respectively, without the need to step down the charging voltage of the battery, which can reduce unnecessary power consumption during the charging process, thereby improving the charging efficiency of the battery. Secondly, during the charge and discharge phase, the charge and discharge circuit can transfer the power from the battery with more power to the battery with less power, which can avoid unnecessary power consumption and thus improve the charge and discharge efficiency of the battery. Thirdly, during the discharge phase, the charge and discharge circuit can provide different operating voltages to different loads, without the need to step down the discharge voltage of the battery, which can reduce unnecessary power consumption during the discharge process and thus improve the discharge efficiency of the battery.

[0045] Figure 2 A schematic diagram of a battery charging and discharging circuit according to an embodiment of the present disclosure is shown in FIG. Figure 2 As shown, the battery 100 includes a first battery cell 11 and a second battery cell 12 connected in series, the negative electrode of the first battery cell 11 is electrically connected to the positive electrode of the second battery cell 12, the positive electrode of the first battery cell 11 is electrically connected to the positive electrode of the battery 100, and the negative electrode of the second battery cell 12 and the negative electrode of the battery 100 are grounded.

[0046] The charge and discharge circuit 200 includes: an equalizing circuit 220 and a voltage conversion circuit 210. The input end of the voltage conversion circuit 210 is electrically connected to the input end of the charge and discharge circuit 200, the first output end of the voltage conversion circuit 210 is electrically connected to the positive electrode of the first battery cell 11, the first end of the equalizing circuit 220 and the first load 310, and the second output end of the voltage conversion circuit 210 is electrically connected to the positive electrode of the second battery cell 12, the second end of the equalizing circuit 220 and the second load 320. The input end of the charge and discharge circuit 200 is externally connected to an adapter for receiving an input voltage Vin during the charging stage.

[0047] The voltage conversion circuit 210 is configured to, during the charging stage, convert the input voltage Vin into a first voltage V1 and a second voltage V2, with the first voltage V1 being twice the second voltage V2, provide the first voltage V1 to the first battery cell 11, provide the second voltage V2 to the second battery cell 12, and provide the first voltage V1 and the second voltage V2 to the load.

[0048] The balancing circuit 220 is configured to obtain the first cell voltage V_11 and the second cell voltage V_12 during the charge and discharge phase, and when the voltage difference between the first cell voltage V_11 and the second cell voltage V_12 is greater than the first preset voltage Vpre1, convert the positive voltage of the discharge cell and provide it to the charge cell until the voltage difference between the first cell voltage V_11 and the second cell voltage V_12 is less than the second preset voltage Vpre2. During the discharge phase, the first power rail Vrail1 and the second power rail Vrail2 are provided to the load.

[0049] Among them, the discharge cell is the cell with the larger cell voltage between the first cell 11 and the second cell 12, and the charge cell is the cell with the smaller cell voltage between the first cell 11 and the second cell 12. The first power rail Vrail1 is the positive voltage of the balanced first cell 11, and the second power rail Vrail2 is the positive voltage of the balanced second cell 12. The second preset voltage Vpre2 is less than the first preset voltage Vpre1.

[0050] For example, Figure 3 A schematic diagram of another charging and discharging circuit provided in an embodiment of the present disclosure is shown in FIG. Figure 3 As shown, the voltage conversion circuit 210 includes: a BUCK circuit 212 and a switch capacitor circuit 211, wherein the input end of the BUCK circuit 212 is electrically connected to the input voltage Vin and the input end of the switch capacitor circuit 211, the output end of the BUCK circuit 212 is electrically connected to the positive electrode of the second battery cell 12, and the output end of the switch capacitor circuit 211 is electrically connected to the positive electrode of the first battery cell 11. For example, the switch capacitor circuit 211 is a 4:2 switch capacitor circuit, which can reduce the voltage of four series-connected battery cells to the voltage of two series-connected battery cells.

[0051] In the charging stage, the switch capacitor circuit 211 can convert the input voltage Vin into a first voltage V1, and the first voltage V1 is a charging voltage matching the first battery cell 11, and the first voltage V1 is provided to the positive electrode of the first battery cell 11 to charge the first battery cell 11. The BUCK circuit 212 can convert the input voltage Vin into a second voltage V2, and the second voltage V2 is a charging voltage matching the second battery cell 12, and the second voltage V2 is provided to the positive electrode of the second battery cell 12 to charge the second battery cell 12.

[0052] In the charging stage, the first load 310 is provided with an operating voltage by the switched capacitor circuit 211, and the second load 320 is provided with an operating voltage by the BUCK circuit 212, so the switched capacitor circuit 211 can provide a first voltage V1 to the first load 310, and the BUCK circuit 212 can provide a second voltage V2 to the second load 320. For example, the first load 310 is a display, a power amplifier and / or a motor with a relatively high operating voltage, and the second load 320 is a low-voltage power management circuit and / or an application processor with a relatively low operating voltage.

[0053] Since the negative electrode of the first battery cell 11 is electrically connected to the positive electrode of the second battery cell 12, and the rated physical parameters of the first battery cell 11 and the second battery cell 12 are equal, the first voltage V1 is twice the second voltage V2. In this way, during the charging stage, the voltage conversion circuit 210 can provide different operating voltages to loads with different rated voltages, without the need to step down the charging voltage of the battery 100, which can reduce unnecessary power consumption during the charging process, thereby improving the charging efficiency of the battery.

[0054] Continue to see Figure 3 The equalization circuit 220 includes: a charge pump 222 and a control module 221. The output end of the control module 221 is electrically connected to the control end of the charge pump 222, the first end of the charge pump 222 is electrically connected to the positive electrode of the first battery cell 11, and the second end of the charge pump 222 is electrically connected to the positive electrode of the second battery cell 12.

[0055] For example, Figure 3 As shown, the control end of the charge pump 222 includes a first control end, a second control end, a third control end and a fourth control end, and the output end of the control module 221 includes a first output end, a second output end, a third output end and a fourth output end, the first control end is electrically connected to the first output end, the second control end is electrically connected to the second output end, the third control end is electrically connected to the third output end, and the fourth control end is electrically connected to the fourth output end. The first output end can output a first sub-control signal QCH_DRV, the second output end can output a second sub-control signal QDH_DRV, the third output end can output a third sub-control signal QCL_DRV, and the fourth output end can output a fourth sub-control signal QDL_DRV.

[0056] The first sub-control signal QCH_DRV and the third sub-control signal QCL_DRV are a group of in-phase signals with the same frequency, and the second sub-control signal QDH_DRV and the fourth sub-control signal QDL_DRV are a group of in-phase signals with the same frequency. Among them, the frequencies of the two groups of in-phase signals are equal and the phases are opposite. For example, the frequencies of the two groups of in-phase signals are any frequency between 500KHz and 1500KHz, and the duty cycles of the two groups of in-phase signals are close to 50%. There is a certain dead time between the two groups of in-phase signals. For example, the dead time is any time between 5ns and 50ns.

[0057] In the charge and discharge stage, when the voltage difference between the first battery cell voltage V_11 and the second battery cell voltage V_12 is greater than the first preset voltage Vpre1 and the first battery cell voltage V_11 is greater than the second battery cell voltage V_12, the first battery cell voltage V_11 is greater than the sum of the second battery cell voltage V_12 and the first preset voltage Vpre1, that is, V_11 > Vpre1 + V_12. The control module 221 generates the first control signal until the first battery cell voltage V_11 is less than the sum of the second battery cell voltage V_12 and the second preset voltage Vpre2, that is, V_11 < Vpre2 + V_12, and the control module 221 stops generating the first control signal. For example, the first preset voltage Vpre1 is any voltage between 15mV and 200mV, and the second preset voltage Vpre2 is any voltage between 5mV and 100mV.

[0058] Among them, the first control signal includes the first sub-control signal QCH_DRV, the second sub-control signal QDH_DRV, the third sub-control signal QCL_DRV, and the fourth sub-control signal QDL_DRV. The first sub-control signal QCH_DRV and the third sub-control signal QCL_DRV are high-level signals, and the second sub-control signal QDH_DRV and the fourth sub-control signal QDL_DRV are low-level signals. In other embodiments, the first sub-control signal QCH_DRV and the third sub-control signal QCL_DRV can be low-level signals, and the second sub-control signal QDH_DRV and the fourth sub-control signal QDL_DRV are high-level signals.

[0059] Under the action of the first control signal, the charge pump 222 operates in the forward operating mode. The charge pump 222 can reduce the positive electrode voltage V_11' of the first battery cell 11 to half of the positive electrode voltage V_11', that is, reduce it to V_11' / 2, and provide V_11' / 2 to the positive electrode of the second battery cell 12. At this time, the first battery cell 11 acts as a discharging battery cell and is in the discharging state, and the second battery cell 12 acts as a charging battery cell and is in the charging state. The balancing circuit 220 can step down the positive electrode voltage of the first battery cell 11 and provide the stepped-down positive electrode voltage to the positive electrode of the second battery cell 12, so as to transfer the excess power in the first battery cell 11 to the second battery cell 12, thereby achieving battery balancing.

[0060] During the charge and discharge stage, when the voltage difference between the voltage V_11 of the first battery cell and the voltage V_12 of the second battery cell is greater than the first preset voltage Vpre1 and the voltage V_11 of the first battery cell is less than the voltage V_12 of the second battery cell, the sum of the voltage V_11 of the first battery cell and the first preset voltage Vpre1 is less than the voltage V_12 of the second battery cell, that is, V_11 + Vpre1 < V_12. The control module 221 generates a second control signal until the sum of the voltage V_11 of the first battery cell and the second preset voltage Vpre2 is greater than the voltage V_12 of the second battery cell, that is, V_11 + Vpre2 > V_12. The control module 221 stops generating the second control signal.

[0061] Among them, the second control signal includes a first sub-control signal QCH_DRV, a second sub-control signal QDH_DRV, a third sub-control signal QCL_DRV, and a fourth sub-control signal QDL_DRV. The first sub-control signal QCH_DRV and the third sub-control signal QCL_DRV are low-level signals, and the second sub-control signal QDH_DRV and the fourth sub-control signal QDL_DRV are high-level signals. In other embodiments, the first sub-control signal QCH_DRV and the third sub-control signal QCL_DRV can be high-level signals, and the second sub-control signal QDH_DRV and the fourth sub-control signal QDL_DRV are low-level signals. It should be noted that each sub-signal in the second control signal is the inverted signal of the corresponding sub-signal in the first control signal.

[0062] Under the action of the second control signal, the charge pump 222 works in the reverse working mode. The charge pump 222 can increase the positive electrode voltage V_12' of the second battery cell 12 to twice the positive electrode voltage V_12', that is, to 2*V_12', and provide 2*V_12' to the positive electrode of the first battery cell 11. At this time, the second battery cell 12 is in a discharging state as a discharging battery cell, and the first battery cell 11 is in a charging state as a charging battery cell. The balancing circuit 220 can boost the positive electrode voltage of the second battery cell 12 and provide the boosted positive electrode voltage to the positive electrode of the first battery cell 11, so as to transfer the excess power in the second battery cell 12 to the first battery cell 11, thereby achieving battery balancing.

[0063] In summary, when the first cell voltage V_11 is greater than the sum of the second cell voltage V_12 and the first preset voltage Vpre1, the balancing circuit 220 can step down the positive voltage V_11' of the first cell 11 and provide it to the second cell 12 until the first cell voltage V_11 is less than the sum of the second cell voltage V_12 and the second preset voltage Vpre2. When the sum of the first cell voltage V_11 and the first preset voltage Vpre1 ​​is less than the second cell voltage V_12, the balancing circuit 220 can step up the positive voltage V_12' of the second cell 12 and provide it to the first cell 11 until the first cell voltage V_11 and the second preset voltage Vpre2 are greater than the second cell voltage V_12. In this way, during the charge and discharge stage, the balancing circuit 220 can transfer the power in the cell with more power to the cell with less power, which can avoid unnecessary power consumption, thereby improving the charge and discharge efficiency of the battery.

[0064] In the discharge stage, the first load 310 is provided with an operating voltage by the first end of the charge pump 222, and the second load 320 is provided with an operating voltage by the second end of the charge pump 222, so the charge pump 222 can provide the first power rail Vrail1 to the first load 310 and provide the second power rail Vrail2 to the second load 320. The first power rail Vrail1 is the positive voltage V_11' of the balanced first battery cell 11, and the second power rail Vrail2 is the positive voltage V_12' of the balanced second battery cell 12. The positive voltage V_11' of the balanced first battery cell 11 is twice the positive voltage V_12' of the balanced second battery cell 12, and the first power rail Vrail1 is twice the second power rail Vrail2.

[0065] In this way, during the discharge phase, the balancing circuit 220 can provide different operating voltages to loads with different rated voltages, without the need to step down the discharge voltage of the battery 100, thereby reducing unnecessary power consumption during the discharge process and improving the discharge efficiency of the battery.

[0066] In the embodiment of the present disclosure, the charge and discharge circuit includes an equalization circuit and a voltage conversion circuit. The voltage conversion circuit converts the input voltage into a first voltage and a second voltage in the charging stage, provides the first voltage to the first cell, provides the second voltage to the second cell, and provides the first voltage and the second voltage to the load. The equalization circuit can obtain the first cell voltage and the second cell voltage in the charge and discharge stage. When the voltage difference between the first cell voltage and the second cell voltage is greater than the first preset voltage, the positive voltage of the discharge cell is converted and provided to the charging cell until the voltage difference between the first cell voltage and the second cell voltage is less than the second preset voltage; the equalization circuit can also provide the first power rail and the second power rail to the load in the discharge stage. In the first aspect, since the first voltage is twice the second voltage, the charge and discharge circuit can provide different working voltages to different loads in the charging stage, without the need to step down the charging voltage of the battery, which can reduce unnecessary power consumption in the charging process, thereby improving the charging efficiency of the battery. In the second aspect, in the charge and discharge stage, the charge and discharge circuit can transfer the power in the cell with more power to the cell with less power, which can avoid unnecessary power consumption, thereby improving the charging and discharging efficiency of the battery. Thirdly, during the discharge phase, the charge and discharge circuit can provide different operating voltages to different loads, without the need to step down the discharge voltage of the battery. This can reduce unnecessary power consumption during the discharge process, thereby improving the discharge efficiency of the battery.

[0067] In some embodiments, see Figure 3 The equalization circuit 220 further includes a voltage detection unit 223 and a voltage comparator 224. The first input end of the voltage detection unit 223 is electrically connected to the positive electrode of the first battery cell 11, the second input end of the voltage detection unit 223 is electrically connected to the positive electrode of the second battery cell 12, the first output end of the voltage detection unit 223 is electrically connected to the first input end of the voltage comparator 224, the second output end of the voltage detection unit 223 is electrically connected to the second input end of the voltage comparator 224, and the output end of the voltage comparator 224 is electrically connected to the input end of the control module 221.

[0068] The voltage detection unit 223 is configured to collect the positive voltage V_11' of the first battery cell 11 and the positive voltage V_12' of the second battery cell 12, and determine the first battery cell voltage V_11 and the second battery cell voltage V_12 based on the positive voltage of the first battery cell 11 and the positive voltage of the second battery cell 12. The voltage comparator 224 is configured to compare the voltage difference between the first battery cell voltage V_11 and the second battery cell voltage V_12 with the first preset voltage Vpre1.

[0069] Exemplarily, the voltage detection unit 223 can collect the positive voltage V_11' of the first battery cell 11 and the positive voltage V_12' of the second battery cell 12. Since the negative electrode of the second battery cell 12 is grounded, the positive voltage V_12' of the second battery cell 12 is the second battery cell voltage V_12, and the voltage difference between the positive voltage V_11' of the first battery cell 11 and the positive voltage V_12' of the second battery cell 12 is the first battery cell voltage V_11. In other words, V_12 = V_12', V_11 = V_11'-V_12'.

[0070] The voltage comparator 224 can receive the first cell voltage V_11 and the second cell voltage V_12, and compare the voltage difference between the first cell voltage V_11 and the second cell voltage V_12 with the first preset voltage Vpre1. When V_11-V_12>Vpre1, the voltage comparator 224 outputs a first comparison result signal, and transmits the first comparison result signal to the control module 221, so that the control module 221 generates a first control signal. When V_12-V_11>Vpre1, the voltage comparator 224 outputs a second comparison result signal, and transmits the second comparison result signal to the control module 221, so that the control module 221 generates a second control signal. For example, the first comparison result signal is a high level signal, and the second comparison result signal is a low level signal; or, the first comparison result signal is a low level signal, and the second comparison result signal is a high level signal.

[0071] In some embodiments, the control module 221 is further configured to stop generating the waveform to put the balancing circuit 220 in a standby state when the voltage difference between the first cell voltage V_11 and the second cell voltage V_12 is less than the second preset voltage Vpre2.

[0072] Exemplarily, the voltage comparator 224 may also compare the voltage difference between the first cell voltage V_11 and the second cell voltage V_12 with the second preset voltage Vpre2. For example, when the first cell voltage V_11 is greater than the sum of the second cell voltage V_12 and the first preset voltage Vpre1, the voltage comparator 224 may compare V_11-V_12 with the second preset voltage Vpre2, that is, compare the sum of the second cell voltage V_12 and the second preset voltage Vpre2 with the first cell voltage V_11, and when the first cell voltage V_11 is less than the sum of the second cell voltage V_12 and the second preset voltage Vpre2, output a third comparison result signal.

[0073] When the sum of the first battery cell voltage V_11 and the first preset voltage Vpre1 ​​is less than the second battery cell voltage V_12, V_11-V_12 can be compared with the second preset voltage Vpre2, that is, the sum of the first battery cell voltage V_11 and the second preset voltage Vpre2 and the second battery cell voltage V_12 are compared, and when the sum of the first battery cell voltage V_11 and the second preset voltage Vpre2 is greater than the second battery cell voltage V_12, a third comparison result signal is output.

[0074] The control module 221 may receive the third comparison result signal, and stop sending power to the charge pump 222 according to the third comparison result signal, so as to put the circuit 220 in a standby state.

[0075] When the circuit 220 is in standby mode, the first input terminal and the second input terminal of the voltage detection unit 223 consume less than 10 μA of current. In this way, the power consumption of the equalization circuit 220 can be reduced as much as possible, that is, the power consumption of the charge and discharge circuit 200 can be reduced, thereby further improving the charge and discharge efficiency of the battery.

[0076] In some embodiments, Figure 2 Based on the embodiment shown, the equalization circuit 220 further includes a wake-up module. The wake-up module is configured to, in the standby state, regularly wake up the voltage detection unit 223, the voltage comparator 224 and the control module 221.

[0077] Exemplarily, the wake-up module includes a standby timer. Based on the duration set by the standby timer, the voltage detection unit 223 is regularly woken up to collect the first cell voltage V_11 and the second cell voltage V_12. The voltage comparator 224 is regularly woken up to compare the voltage difference between the first cell voltage V_11 and the second cell voltage V_12 with the first preset voltage Vpre1. The control module 221 is regularly woken up to determine whether to send a wave, thereby determining whether the equalizing circuit 220 ends the standby state. For example, the standby timer is set to 1ms, and the voltage detection unit 223, the voltage comparator 224 and the control module 221 are prohibited from working within 1ms. When it exceeds 1ms, the voltage detection unit 223, the voltage comparator 224 and the control module 221 work for about 50μs. If the equalizing circuit 220 is still in the standby state after 50μs, it enters the next 1ms timing, and repeats.

[0078] In this way, the power consumption of the charge and discharge circuit 200 in the standby state can be further reduced, thereby further improving the charge and discharge efficiency of the battery.

[0079] In some embodiments, Figure 2Based on the illustrated embodiment, the equalization circuit 220 further includes an enabling module, which is configured to enable the equalization circuit 220 when an enabling signal is received, and to disable the equalization circuit 220 when a disabling signal is received.

[0080] Exemplarily, the enable signal is a high level signal, and the disable signal is a low level signal; or, the enable signal is a low level signal, and the disable signal is a high level signal. After receiving the enable signal, the enable module enables the equalization circuit 220, and after receiving the disable signal, the enable module prohibits enabling the equalization circuit 220.

[0081] When the equalizing circuit 220 is in the disabled state, the first input terminal and the second input terminal of the voltage detection unit 223 consume current less than 1 μA, which reduces the power consumption of the equalizing circuit 220 as much as possible, that is, reduces the power consumption of the charging and discharging circuit, thereby further improving the charging and discharging efficiency of the battery.

[0082] In some embodiments, Figure 2 Based on the embodiment shown, the equalization circuit 220 further includes a voltage setting module. The voltage setting module is configured to set a first preset voltage Vpre1 ​​and a second preset voltage Vpre2.

[0083] Exemplarily, the voltage setting module is electrically connected to the voltage comparator 224, and based on the voltage setting module, a first preset voltage Vpre1 ​​is input to the voltage comparator 224, so that the voltage comparator 224 can compare the voltage difference between the first cell voltage V_11 and the second cell voltage V_12 with the first preset voltage Vpre1. Based on the voltage setting module, a second preset voltage Vpre2 may be input to the voltage comparator 224, so that the voltage comparator 224 can compare the voltage difference between the first cell voltage V_11 and the second cell voltage V_12 with the second preset voltage Vpre2.

[0084] In some embodiments, Figure 4 A structural diagram of an equalization circuit provided in an embodiment of the present disclosure is shown in FIG. Figure 4 As shown, the charge pump 222 includes: a first transistor Q CH , the second transistor Q DH , the third transistor Q CL , the fourth transistor Q DL And the flying capacitor C FLY .

[0085] Among them, the first transistor Q CH The first end of the first transistor Q is electrically connected to the positive electrode of the first battery cell 11. CH The second end is electrically connected to the flying capacitor C FLY The first plate and the second transistor Q DH The first terminal of the second transistor QDH The second end of the third transistor Q CL The first end of the second battery cell 12 and the positive electrode of the third transistor Q CL The second end is electrically connected to the flying capacitor C FLY The second plate and the fourth transistor Q DL One end of the fourth transistor Q DL The second end of the first transistor Q CH The control terminal of the second transistor Q DH The control terminal of the third transistor Q CL The control terminal and the fourth transistor Q DL The control end is electrically connected to the first output end, the second output end, the third output end and the fourth output end of the control module 221 in a one-to-one correspondence.

[0086] The first transistor Q CH , the second transistor Q DH , the third transistor Q CL , the fourth transistor Q DL The control module 221 is integrated into the equalizer chip 230. The peripheral circuit of the equalizer chip 230 includes a flying capacitor C FLY .

[0087] Exemplarily, the first transistor Q CH , the second transistor Q DH , the third transistor Q CL and the fourth transistor Q DL is an N-type metal oxide semiconductor field effect transistor (NMOS), the first transistor Q CH The gate of the second transistor Q DH The gate of the third transistor Q CL The gate of the fourth transistor Q DL The gate may receive the fourth sub-control signal QDL_DRV.

[0088] The first sub-control signal QCH_DRV can control the first transistor Q CH The second sub-control signal QDH_DRV can control the on and off of the second transistor Q DH The third sub-control signal QCL_DRV can control the on and off of the third transistor Q CL The fourth sub-control signal QDL_DRV can control the on and off of the fourth transistor Q DLThe charge pump 222 operates in a forward working mode under the action of the first control signal to achieve a 2:1 voltage reduction function. Under the action of the second control signal, the charge pump 222 operates in a reverse working mode to achieve a 1:2 voltage boost function.

[0089] The first transistor Q CH , the second transistor Q DH , the third transistor Q CL , the fourth transistor Q DL The control module 221 is integrated into the balancing chip 230 to miniaturize the balancing circuit 220. The balancing chip 230 may also integrate at least one of a voltage detection unit 223, a voltage comparator 224, a wake-up module, an enable module, and a voltage setting module. The peripherals electrically connected to the balancing chip 230 include a flying capacitor C FLY , may also include at least one of a bootstrap capacitor C, a first input-output capacitor C1, a second input-output capacitor C2 and a resistor R.

[0090] For example, the first transistor Q CH , the second transistor Q DH , the third transistor Q CL , the fourth transistor Q DL , the control module 221, the voltage detection unit 223, the voltage comparator 224, the wake-up module, the enable module and the voltage setting module are integrated in the balancing chip 230, and the obtained balancing chip 230 is as follows: Figure 5 As shown, Figure 5 A schematic diagram of the structure of a balancing chip provided in an embodiment of the present disclosure is shown in FIG. Figure 5 shown.

[0091] The balancing chip 230 includes a pin CFL, a pin CFH, a pin BST, a pin V1X, a pin V2X, a pin SET, a pin PGND and a pin EN_BAL, wherein a flying capacitor C is electrically connected between the pin CFL and the pin CHL. FLY , the bootstrap capacitor C is electrically connected between pin CFH and pin BST, pin V1X is electrically connected to the positive electrode of the second battery cell 12 and the first plate of the second input-output capacitor C2, pin V2X is electrically connected to the positive electrode of the first battery cell 11 and the first plate of the first input-output capacitor C1, and the second plate of the first input-output capacitor C1 and the second plate of the second input-output capacitor C2 are grounded. Pin SET is electrically connected to the first end of the resistor R, and the second end of the resistor R is grounded. The first preset voltage Vpre1 ​​can be flexibly set based on the resistance value of the resistor R. Pin EN_BAL is used to receive an enable signal and a disable signal, and pin PGND is grounded.

[0092] Unless the context clearly indicates otherwise, the singular form of the words used herein and in the appended claims includes the plural and vice versa. Thus, when referring to the singular, the plural form of the corresponding term is generally included. Similarly, the words "comprise" and "include" are to be interpreted as inclusive rather than exclusive. Likewise, the terms "include" and "or" should be interpreted as inclusive unless such interpretation is expressly prohibited herein. Where the term "example" is used herein, particularly when it is located after a group of terms, the "example" is merely exemplary and illustrative and should not be considered exclusive or comprehensive.

[0093] Further aspects and scopes of adaptability become apparent from the description provided herein. It should be understood that various aspects of the present application can be implemented individually or in combination with one or more other aspects. It should also be understood that the description and specific embodiments herein are intended for purposes of illustration only and are not intended to limit the scope of the present application.

[0094] Several embodiments of the present disclosure are described in detail above, but it is obvious that those skilled in the art can make various modifications and variations to the embodiments of the present disclosure without departing from the spirit and scope of the present disclosure. The protection scope of the present disclosure is defined by the attached claims.

Claims

1. A battery charging and discharging circuit, characterized in that: The battery comprises a first battery cell and a second battery cell connected in series, wherein the negative electrode of the first battery cell is electrically connected to the positive electrode of the second battery cell; The charging and discharging circuit includes: an equalizing circuit and a voltage conversion circuit; The voltage conversion circuit is configured to, in a charging stage, convert an input voltage into a first voltage and a second voltage, wherein the first voltage is twice the second voltage, provide the first voltage to the first battery cell, provide the second voltage to the second battery cell, and provide the first voltage and the second voltage to a load; The balancing circuit is configured to, in a charging and discharging stage, obtain a first cell voltage and a second cell voltage, and when a voltage difference between the first cell voltage and the second cell voltage is greater than a first preset voltage, convert the positive voltage of the discharging cell and provide it to the charging cell until the voltage difference between the first cell voltage and the second cell voltage is less than a second preset voltage; in a discharging stage, provide a first power rail and a second power rail to a load; Among them, the discharging cell is the cell with the larger cell voltage between the first cell and the second cell, and the charging cell is the cell with the smaller cell voltage between the first cell and the second cell; the first power rail is the positive electrode voltage of the first cell after equalization, and the second power rail is the positive electrode voltage of the second cell after equalization; the second preset voltage is less than the first preset voltage.

2. The battery charging and discharging circuit according to claim 1, characterized in that: The balancing circuit is further configured to, when the first battery cell voltage is greater than the sum of the second battery cell voltage and the first preset voltage, step down the positive voltage of the first battery cell and provide it to the second battery cell until the first battery cell voltage is less than the sum of the second battery cell voltage and the second preset voltage; when the sum of the first battery cell voltage and the first preset voltage is less than the second battery cell voltage, step up the positive voltage of the second battery cell and provide it to the first battery cell until the sum of the first battery cell voltage and the second preset voltage is greater than the second battery cell voltage.

3. The battery charging and discharging circuit according to claim 2, characterized in that: The balancing circuit comprises: a charge pump and a control module; The output end of the control module is electrically connected to the control end of the charge pump, the first end of the charge pump is electrically connected to the positive electrode of the first battery cell, and the second end of the charge pump is electrically connected to the positive electrode of the second battery cell; The control module is configured to, when the first battery cell voltage is greater than the sum of the second battery cell voltage and the first preset voltage, generate a first control signal until the first battery cell voltage is less than the sum of the second battery cell voltage and the second preset voltage, and stop generating the first control signal; when the sum of the first battery cell voltage and the first preset voltage is less than the second battery cell voltage, generate a second control signal until the sum of the first battery cell voltage and the second preset voltage is greater than the second battery cell voltage, and stop generating the second control signal; The charge pump is configured to, under the action of the first control signal, reduce the positive voltage of the first battery cell to half and provide it to the second battery cell; under the action of the second control signal, increase the positive voltage of the second battery cell to twice and provide it to the first battery cell.

4. The battery charging and discharging circuit according to claim 3, characterized in that: The equalization circuit also includes a voltage detection unit and a voltage comparator; The first input end of the voltage detection unit is electrically connected to the positive electrode of the first battery cell, the second input end of the voltage detection unit is electrically connected to the positive electrode of the second battery cell, the first output end of the voltage detection unit is electrically connected to the first input end of the voltage comparator, the second output end of the voltage detection unit is electrically connected to the second input end of the voltage comparator, and the output end of the voltage comparator is electrically connected to the input end of the control module; The voltage detection unit is configured to collect the positive electrode voltage of the first battery cell and the positive electrode voltage of the second battery cell, and determine the first battery cell voltage and the second battery cell voltage based on the positive electrode voltage of the first battery cell and the positive electrode voltage of the second battery cell; The voltage comparator is configured to compare a voltage difference between the first battery cell voltage and the second battery cell voltage with the first preset voltage.

5. The battery charging and discharging circuit according to claim 3, characterized in that: The control module is further configured to stop generating waves to put the balancing circuit in a standby state when the voltage difference between the first battery cell voltage and the second battery cell voltage is less than the second preset voltage.

6. The battery charging and discharging circuit according to claim 4, characterized in that: The equalization circuit also includes a wake-up module; The wake-up module is configured to, in a standby state, periodically wake up the voltage detection unit, the voltage comparator and the control module.

7. The battery charging and discharging circuit according to any one of claims 1 to 6, characterized in that: The balancing circuit also includes an enabling module; The enabling module is configured to enable the equalizing circuit when an enabling signal is received, and to prohibit enabling the equalizing circuit when a disabling signal is received.

8. The battery charging and discharging circuit according to any one of claims 1 to 6, characterized in that: The equalization circuit also includes a voltage setting module; The voltage setting module is configured to set the first preset voltage and the second preset voltage.

9. The battery charging and discharging circuit according to any one of claims 1 to 6, characterized in that: The voltage conversion circuit includes: a BUCK circuit and a switched capacitor circuit; The input end of the BUCK circuit is electrically connected to the input voltage and the input end of the switch capacitor circuit, the output end of the BUCK circuit is electrically connected to the positive electrode of the second battery cell, and the output end of the switch capacitor circuit is electrically connected to the positive electrode of the first battery cell.

10. The battery charging and discharging circuit according to claim 3, characterized in that: The charge pump comprises: a first transistor, a second transistor, a third transistor, a fourth transistor and a flying capacitor; A first end of the first transistor is electrically connected to the positive electrode of the first battery cell, a second end of the first transistor is electrically connected to the first electrode plate of the flying capacitor and the first end of the second transistor, a second end of the second transistor is electrically connected to the first end of the third transistor and the positive electrode of the second battery cell, a second end of the third transistor is electrically connected to the second electrode plate of the flying capacitor and one end of the fourth transistor, a second end of the fourth transistor is grounded, and a control end of the first transistor, a control end of the second transistor, a control end of the third transistor and a control end of the fourth transistor are electrically connected to a first output end, a second output end, a third output end and a fourth output end of the control module in a one-to-one correspondence; The first transistor, the second transistor, the third transistor, the fourth transistor and the control module are integrated in a balancing chip, and the peripheral circuit of the balancing chip includes the flying capacitor.

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