Balancing control circuit of battery system
By designing the battery system equalization control circuit, the communication between the main control module and the slave control module is used to achieve real-time monitoring and equalization control of the single battery voltage, and the two-way active equalization method is adopted to solve the problem of poor balance effect in the existing technology, and the effects of fast equalization and small energy loss are achieved, which extends the service life of the battery system.
Patent Information
- Application Number
- CN202421820649.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-30
- Publication Date
- 2025-05-23
- Estimated Expiration
- 2034-07-30
AI Technical Summary
The existing battery balance charging circuit has poor balance effect and cannot effectively adapt to the fast balance needs of large-capacity batteries, resulting in a shortening of the service life of the battery system.
A battery system equalization control circuit is designed, including a master control module and a slave control module. Each slave control module includes a first controller, a first voltage acquisition circuit and a first DC/DC circuit. Through communication between the master control module and the slave control module, real-time monitoring and equalization control of the voltage of the single battery is realized. Bidirectional active equalization method is adopted to charge a single battery with a lower voltage or discharge a single battery with a higher slave voltage through the equalization bus.
It achieves rapid balance, has small energy loss, extends the service life of the lead-acid battery system, and reduces the cost of the entire life cycle.
Smart Images
Figure CN222897076U_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to the field of power supply technology, and in particular to a battery system balancing control circuit. Background Art
[0002] When traditional lead-acid batteries are used in series, due to the inherent internal resistance characteristics of lead-acid batteries, after long-term use, the voltage difference of each single battery becomes obvious, and the single battery with poor characteristics reaches the end of its life cycle first, which will cause the entire battery system to fail and shorten its service life. The battery equalization charging circuit detects the voltage of each single battery in real time to ensure that the voltage between them remains balanced. When a voltage difference is found, the circuit will take measures to adjust it to prevent voltage imbalance and extend the service life of the battery pack.
[0003] Most of the existing balancing circuits use passive balancing, which releases the energy of high-energy batteries to resistors, which invisibly increases system losses, and has very low balancing capabilities, and cannot meet the rapid balancing needs of large-capacity batteries. Utility Model Content
[0004] The embodiment of the present disclosure provides a battery system balancing control circuit to solve the problem of poor balancing effect of the existing battery balancing charging circuit.
[0005] The embodiment of the present disclosure provides a battery system balancing control circuit, wherein the battery system includes a plurality of single cells connected in series, and the battery system balancing control circuit includes a master control module and a plurality of slave control modules.
[0006] Each of the slave control modules comprises a first controller, a first voltage acquisition circuit and a first DC / DC circuit, wherein the first voltage acquisition circuit is used to acquire voltage data of a single cell, an output end of the first voltage acquisition circuit is connected to a signal input end of the first controller, a first end of the first DC / DC circuit is used to connect to a single cell, a second end of the first DC / DC circuit is used to connect to a balancing bus, and a control end of the first DC / DC circuit is connected to a first signal output end of the first controller;
[0007] The main control module includes a second controller and a second DC / DC circuit, a first end of the second DC / DC circuit is used to connect to the battery system, and a control end of the second DC / DC circuit is connected to a signal output end of the second controller;
[0008] The second controller is configured to send control information to the first controller based on the single cell voltage data to control the operation of the first DC / DC circuit to control the single cell to discharge to the balancing bus or to charge the single cell from the balancing bus.
[0009] In an exemplary embodiment of the present disclosure, the first DC / DC circuit includes a transformer, a first switch tube, a second switch tube, a first capacitor and a second capacitor.
[0010] The first end of the first coil of the transformer is used to connect to the positive electrode of the single battery, the second end of the first coil of the transformer is connected to the first end of the first switch tube, the second end of the first switch tube is used to connect to the negative electrode of the single battery, and the first capacitor is connected in parallel with both ends of the single battery.
[0011] The first end of the second coil of the transformer is used to be connected to the positive electrode of the balanced bus, the second end of the second coil of the transformer is connected to the first end of the second switch tube, the second end of the second switch tube is used to be connected to the negative electrode of the balanced bus, and the two ends of the second capacitor are connected in parallel with the balanced bus.
[0012] The first signal output end of the first controller includes a second signal output end and a third signal output end, the control end of the first switch tube is connected to the second signal output end of the first controller, and the control end of the second switch tube is connected to the third signal output end of the first controller.
[0013] In an exemplary embodiment of the present disclosure, the first DC / DC circuit further includes an absorption circuit, which includes a resistor R1, a capacitor C1 and a diode D1, an anode of the diode D1 is connected to the second end of the first coil of the transformer, a cathode of the diode D1 is connected to the first end of the capacitor C1, the second end of the capacitor C1 is connected to the first end of the first coil of the transformer, and the resistor R1 is connected in parallel with the capacitor C1.
[0014] In an exemplary embodiment of the present disclosure, the slave control module further includes a temperature acquisition circuit, and the temperature acquisition circuit is used to acquire the temperature of the single battery.
[0015] In an exemplary embodiment of the present disclosure, a driving circuit is provided between the control end of the first DC / DC circuit and the signal output end of the first controller, and the driving circuit includes an operational amplifier U2A and a comparator U3 connected in sequence.
[0016] The non-inverting input terminal of the operational amplifier U2A is connected to the third signal output terminal of the first controller, the inverting input terminal of the operational amplifier U2A is connected to the output terminal of the second voltage acquisition circuit, the output terminal of the operational amplifier U2A is connected to the inverting input terminal of the operational amplifier U2A through a multi-channel resistor feedback, the branches of the multi-channel resistor are all connected in series with a selection switch, the control terminal of the selection switch is connected to the fourth signal output terminal of the first controller, and the second voltage acquisition circuit is used to collect the voltage of the first terminal of the first DC / DC circuit;
[0017] The output end of the operational amplifier U2A is connected to the non-inverting input end of the comparator U3, the inverting input end of the comparator U3 is connected to the triangle wave generating circuit, and the output end of the comparator U3 is the output end of the driving circuit, which is connected to the control end of the second switch tube.
[0018] In an exemplary embodiment of the present disclosure, the battery system balancing control circuit further includes a current amplifier U4, the input end of the current amplifier U4 is connected to the output end of the comparator U3, and the output end of the current amplifier U4 is the output end of the drive circuit.
[0019] In an exemplary embodiment of the present disclosure, the master control module is connected to a plurality of slave control modules via a CAN communication module.
[0020] The battery system balancing control circuit provided by the embodiment of the present disclosure has the following working principles and beneficial effects:
[0021] In the disclosed embodiment, the first controller sends the collected single cell voltage data to the second controller, the second controller selects the single cells with lower voltage, and then sends a charging instruction to the corresponding first controller, the first controller controls the first DC / DC circuit to work, and the balancing bus charges the single cells with lower voltage; further, the second controller can also select the single cells with higher voltage, and then send a discharge instruction to the corresponding first controller, the first controller controls the first DC / DC circuit to work, and the single cells with higher voltage are discharged to the balancing bus. The voltage of the balancing bus is obtained by the battery system through the first DC / DC circuit.
[0022] The disclosed embodiment replenishes energy for the single battery with lower voltage through the second DC / DC circuit built into the master control module and the first DC / DC circuit built into the slave control module; the energy of the single battery with higher voltage can also be transferred to the balancing bus through the first DC / DC circuit built into the slave control module, thus realizing bidirectional active balancing. It has the characteristics of fast balancing speed and small energy loss, which can extend the service life of the lead-acid battery system and reduce the full life cycle cost. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.
[0024] Figure 1 is a principle block diagram of a battery system balancing control circuit provided by an embodiment of the present disclosure;
[0025] Figure 2 It is a schematic diagram of a driving circuit provided in an embodiment of the present disclosure. DETAILED DESCRIPTION
[0026] In order to enable people in the technical field to better understand the present solution, the technical solution in the embodiment of the present solution will be clearly described below in conjunction with the drawings in the embodiment of the present solution. Obviously, the described embodiment is an embodiment of a part of the present solution, not all of the embodiments. Based on the embodiments in the present solution, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present solution.
[0027] The term "including" and any other variations in the specification and claims of this solution and the above drawings mean "including but not limited to", and is intended to cover non-exclusive inclusions and is not limited to the examples listed in the text. In addition, the terms "first" and "second" are used to distinguish different objects, not to describe a specific order.
[0028] The following is a detailed description of the implementation of the present disclosure in conjunction with the specific drawings:
[0029] Figure 1 This is a principle block diagram of a battery system balancing control circuit provided by an embodiment of the present disclosure. Figure 1 The battery system includes a plurality of single cells connected in series, which includes a battery system balancing control circuit master control module and a plurality of slave control modules.
[0030] Each slave control module includes a first controller, a first voltage acquisition circuit and a first DC / DC circuit, the first voltage acquisition circuit is used to collect single cell voltage data, the output end of the first voltage acquisition circuit is connected to the signal input end of the first controller, the first end of the first DC / DC circuit is used to connect to the single cell, the second end of the first DC / DC circuit is used to connect to the balancing bus, and the control end of the first DC / DC circuit is connected to the first signal output end of the first controller;
[0031] The main control module includes a second controller and a second DC / DC circuit, a first end of the second DC / DC circuit is used to connect to the battery system, and a control end of the second DC / DC circuit is connected to a signal output end of the second controller;
[0032] The second controller is configured to send control information to the first controller based on the single cell voltage data to control the operation of the first DC / DC circuit to control the single cell to discharge to the balancing bus or to charge the single cell from the balancing bus.
[0033] In the embodiment of the present disclosure, the first controller (i.e. Figure 1The slave control CPU in the control module sends the collected single cell voltage data to the second controller (i.e. Figure 1 The second controller selects the single cells with lower voltage, and then sends a charging instruction to the corresponding first controller. The first controller controls the first DC / DC circuit to charge the single cells with lower voltage through the balancing bus. Furthermore, the second controller can also select the single cells with higher voltage, and then send a discharge instruction to the corresponding first controller. The first controller controls the first DC / DC circuit to discharge the single cells with higher voltage to the balancing bus. The voltage of the balancing bus is converted by the battery system through the first DC / DC circuit.
[0034] The disclosed embodiment replenishes energy for the single battery with lower voltage through the second DC / DC circuit built into the master control module and the first DC / DC circuit built into the slave control module; the energy of the single battery with higher voltage can also be transferred to the balancing bus through the first DC / DC circuit built into the slave control module, thus realizing bidirectional active balancing. It has the characteristics of fast balancing speed and small energy loss, which can extend the service life of the lead-acid battery system and reduce the full life cycle cost.
[0035] Reference Figure 1 In an exemplary embodiment of the present disclosure, the first DC / DC circuit includes a transformer, a first switch tube, a second switch tube, a first capacitor and a second capacitor.
[0036] The first end of the first coil of the transformer is used to connect to the positive electrode of the single battery, the second end of the first coil of the transformer is connected to the first end of the first switch tube, the second end of the first switch tube is used to connect to the negative electrode of the single battery, and the first capacitor is connected in parallel with both ends of the single battery.
[0037] The first end of the second coil of the transformer is used to be connected to the positive electrode of the balancing bus, the second end of the second coil of the transformer is connected to the first end of the second switch tube, the second end of the second switch tube is used to be connected to the negative electrode of the balancing bus, and the two ends of the second capacitor are connected in parallel with the balancing bus.
[0038] The first signal output end of the first controller includes a second signal output end and a third signal output end, the control end of the first switch tube is connected to the second signal output end of the first controller, and the control end of the second switch tube is connected to the third signal output end of the first controller.
[0039] In this embodiment, the transformer T1, the first switch tube Q1 and the second switch tube Q2 form a bidirectional isolated flyback power supply circuit, which can realize charging of the single battery by the balancing bus or discharge of the single battery to the balancing bus.
[0040] When the voltage of the single cell is too low and the balancing bus needs to charge the single cell, the third signal output terminal of the first controller outputs the PWM2 control signal to the control terminal of the second switch tube Q2 to control the second switch tube Q2 to be turned on or off at high frequency, and the second signal output terminal of the first controller outputs a constant low-level signal to the control terminal of the first switch tube Q1 to control the first switch tube Q1 to be continuously turned off. When the PWM2 control signal is at a high level, the second switch tube Q2 is turned on, the second coil of the transformer T1 stores energy, and the first capacitor provides charging energy for the single cell; when the PWM2 control signal is at a low level, the second switch tube Q2 is turned off, the energy stored in the second coil of the transformer T1 is coupled to the first coil, and the first coil charges the first capacitor through the anti-parallel diode in the first switch tube Q1, and the first capacitor stores energy.
[0041] When the voltage of a single cell is too high and the single cell needs to discharge to the balancing bus, the second signal output terminal of the first controller outputs a PWM1 control signal to the control terminal of the first switch tube Q1 to control the high-frequency conduction or shutdown of the first switch tube Q1, and the third signal output terminal of the first controller outputs a constant low-level signal to the control terminal of the second switch tube Q2 to control the second switch tube Q2 to be continuously shut down. When the PWM1 control signal is at a high level, the first switch tube Q1 is turned on, the first coil of the transformer T1 stores energy, and the second capacitor discharges to the balancing bus; when the PWM1 control signal is at a low level, the first switch tube Q1 is turned off, the energy stored in the first coil of the transformer T1 is coupled to the second coil, and the second coil charges the second capacitor through the anti-parallel diode in the second switch tube Q2, and the second capacitor stores energy.
[0042] Reference Figure 1 In an exemplary embodiment of the present disclosure, the first DC / DC circuit further includes an absorption circuit, the absorption circuit includes a resistor R1, a capacitor C1 and a diode D1, the anode of the diode D1 is connected to the second end of the first coil of the transformer, the cathode of the diode D1 is connected to the first end of the capacitor C1, the second end of the capacitor C1 is connected to the first end of the first coil of the transformer, and the resistor R1 is connected in parallel with the capacitor C1.
[0043] In an embodiment, the RCD absorption circuit can suppress the voltage spike generated when the first switch tube Q1 is turned off, leaving enough voltage margin for the first switch tube Q1 to avoid damage due to excessively high voltage or affecting the service life of the first switch tube Q1.
[0044] In an exemplary embodiment of the present disclosure, the slave control module further includes a temperature acquisition circuit, and the temperature acquisition circuit is used to acquire the temperature of the single battery.
[0045] In this embodiment, by detecting the voltage of the single cell and combining it with the temperature of the battery, accurate control of the balancing process of each single cell can be achieved to ensure that each single cell can be fully balanced.
[0046] In addition, during the balanced charging process, adjusting the charging strategy according to the battery temperature can optimize the charging process and improve charging efficiency and battery performance. For example, in a low temperature environment, appropriately increasing the charging voltage and current can accelerate battery charging; in a high temperature environment, the charging voltage and current need to be reduced to prevent the battery from overheating.
[0047] Reference Figure 2 In an exemplary embodiment of the present disclosure, a driving circuit is provided between the control end of the first DC / DC circuit and the signal output end of the first controller, and the driving circuit includes an operational amplifier U2A and a comparator U3 connected in sequence.
[0048] The non-inverting input terminal of the operational amplifier U2A is connected to the third signal output terminal of the first controller, the inverting input terminal of the operational amplifier U2A is connected to the output terminal of the second voltage acquisition circuit, the output terminal of the operational amplifier U2A is connected to the inverting input terminal of the operational amplifier U2A through a multi-channel resistor feedback, the branches of the multi-channel resistor are all connected in series with a selection switch, the control terminal of the selection switch is connected to the fourth signal output terminal of the first controller, and the second voltage acquisition circuit is used to collect the voltage of the first terminal of the first DC / DC circuit;
[0049] The output end of the operational amplifier U2A is connected to the non-inverting input end of the comparator U3, the inverting input end of the comparator U3 is connected to the triangle wave generating circuit, and the output end of the comparator U3 is the output end of the driving circuit, which is connected to the control end of the second switch tube.
[0050] In this embodiment, the process of charging the single battery BAT-1 from the balancing bus is taken as an example. In this process, the first switch tube Q1 remains turned on, the second switch tube Q2 is turned on or off at a high frequency, the input voltage of the first DC / DC circuit is the voltage of the balancing bus, and the output voltage of the first DC / DC circuit is the voltage across the first capacitor E1.
[0051] The modulation process of the control signal PWM2 of the second switch tube Q2 is as follows:
[0052] The operational amplifier U2A constitutes a subtraction circuit. The DAC module of the first controller outputs a voltage command value (third control signal) to the non-inverting input terminal of the operational amplifier U2A. The voltage command value is used as the command value of the output voltage of the first DC / DC circuit. The second voltage acquisition circuit acquires the actual value of the output voltage of the first DC / DC circuit. The output terminal of the second voltage acquisition circuit is connected to the inverting input terminal of the operational amplifier U2A. The operational amplifier U2A outputs the difference between the command value and the actual value of the output voltage of the first DC / DC circuit. The difference is connected to the non-inverting input terminal of the comparator U3, and is compared with the triangular carrier output by the triangular wave generating circuit, and the PWM2 signal is output at the output terminal of the comparator U3. The larger the difference, the larger the duty cycle of the PWM2 signal, and the longer the conduction time of the second switch tube Q2, thereby increasing the output voltage of the first DC / DC circuit to reduce the difference between the actual value of the output voltage and the command value.
[0053] Among them, considering that when the output voltage of the first DC / DC circuit is high, the charging current of the single battery is large, and the large charging current will cause the battery temperature to rise. To avoid this problem, this embodiment adds a selection switch U1 to the feedback branch of the operational amplifier U2A. By selecting different resistors R23, R24 and R25, the discharge multiple of the operational amplifier U2A can be adjusted, thereby adjusting the output voltage of the operational amplifier U2A to adjust the duty cycle of the PWM2 signal and the output voltage of the first DC / DC circuit. That is, the setting of the selection switch in this embodiment realizes the flexible adjustment of the output voltage of the first DC / DC circuit, and avoids the temperature increase of the single battery caused by the excessive output voltage of the first DC / DC circuit.
[0054] Reference Figure 2 In an exemplary embodiment of the present disclosure, the battery system balancing control circuit further includes a current amplifier U4, an input end of the current amplifier U4 is connected to an output end of the comparator U3, and an output end of the current amplifier U4 is an output end of the drive circuit.
[0055] In this embodiment, the current amplifier U4 can increase the driving capability of the PWM2 signal, which is beneficial to achieve reliable driving of the second switch tube Q2.
[0056] In an exemplary embodiment of the present disclosure, the master control module is connected to a plurality of slave control modules via a CAN communication module.
[0057] In this embodiment, the data between the master control module and multiple slave control modules are transmitted through the CAN bus, using two signals CANH and CANL for communication, and only two lines are needed to realize data transmission between multiple nodes. At the same time, CAN communication has the advantages of high real-time performance, strong anti-interference ability, and long transmission distance.
[0058] The above embodiments are only used to illustrate the technical solutions of the present disclosure, rather than to limit them. Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present disclosure.
Claims
1. A battery system balancing control circuit, the battery system includes a plurality of single cells connected in series, characterized in that: It includes a master control module and a plurality of slave control modules, each of which includes a first controller, a first voltage acquisition circuit and a first DC / DC circuit, wherein the first voltage acquisition circuit is used to acquire single cell voltage data, the output end of the first voltage acquisition circuit is connected to the signal input end of the first controller, the first end of the first DC / DC circuit is used to connect to the single cell, the second end of the first DC / DC circuit is used to connect to the balancing bus, and the control end of the first DC / DC circuit is connected to the first signal output end of the first controller; The main control module includes a second controller and a second DC / DC circuit, a first end of the second DC / DC circuit is used to connect to the battery system, and a control end of the second DC / DC circuit is connected to a signal output end of the second controller; The second controller is configured to send control information to the first controller based on the single cell voltage data to control the operation of the first DC / DC circuit to control the single cell to discharge to the balancing bus or to charge the single cell from the balancing bus.
2. The battery system balancing control circuit according to claim 1, characterized in that: The first DC / DC circuit includes a transformer, a first switch tube, a second switch tube, a first capacitor and a second capacitor. The first end of the first coil of the transformer is used to connect to the positive electrode of the single battery, the second end of the first coil of the transformer is connected to the first end of the first switch tube, the second end of the first switch tube is used to connect to the negative electrode of the single battery, and the first capacitor is connected in parallel with both ends of the single battery. The first end of the second coil of the transformer is used to be connected to the positive electrode of the balancing bus, the second end of the second coil of the transformer is connected to the first end of the second switch tube, the second end of the second switch tube is used to be connected to the negative electrode of the balancing bus, and the two ends of the second capacitor are connected in parallel with the balancing bus. The first signal output end of the first controller includes a second signal output end and a third signal output end, the control end of the first switch tube is connected to the second signal output end of the first controller, and the control end of the second switch tube is connected to the third signal output end of the first controller.
3. The battery system balancing control circuit according to claim 2, characterized in that: The first DC / DC circuit also includes an absorption circuit, which includes a resistor R1, a capacitor C1 and a diode D1, an anode of the diode D1 is connected to the second end of the first coil of the transformer, a cathode of the diode D1 is connected to the first end of the capacitor C1, the second end of the capacitor C1 is connected to the first end of the first coil of the transformer, and the resistor R1 is connected in parallel with the capacitor C1.
4. The battery system balancing control circuit according to claim 1, characterized in that: The slave control module further includes a temperature acquisition circuit, and the temperature acquisition circuit is used to acquire the temperature of the single battery.
5. The battery system balancing control circuit according to claim 2, characterized in that: A driving circuit is provided between the control end of the first DC / DC circuit and the signal output end of the first controller, and the driving circuit includes an operational amplifier U2A and a comparator U3 connected in sequence. The non-inverting input terminal of the operational amplifier U2A is connected to the third signal output terminal of the first controller, the inverting input terminal of the operational amplifier U2A is connected to the output terminal of the second voltage acquisition circuit, the output terminal of the operational amplifier U2A is connected to the inverting input terminal of the operational amplifier U2A through a multi-channel resistor feedback, the branches of the multi-channel resistor are all connected in series with a selection switch, the control terminal of the selection switch is connected to the fourth signal output terminal of the first controller, and the second voltage acquisition circuit is used to collect the voltage of the first terminal of the first DC / DC circuit; The output end of the operational amplifier U2A is connected to the non-inverting input end of the comparator U3, the inverting input end of the comparator U3 is connected to the triangle wave generating circuit, and the output end of the comparator U3 is the output end of the driving circuit, which is connected to the control end of the second switch tube.
6. The battery system balancing control circuit according to claim 5, characterized in that: It also includes a current amplifier U4, the input end of the current amplifier U4 is connected to the output end of the comparator U3, and the output end of the current amplifier U4 is the output end of the drive circuit.
7. The battery system balancing control circuit according to claim 1, characterized in that: The master control module is connected to a plurality of slave control modules via a CAN communication module.