Drive circuit and battery pack

Abstract

Embodiments of the present application provide a driving circuit and a battery pack, wherein the circuit comprises: a first driving sub-circuit and a second driving sub-circuit connected with the first driving sub-circuit, wherein the first driving sub-circuit is configured to receive a control signal sent by a battery management system and determine an output first level signal according to the control signal; and the second driving sub-circuit is configured to receive a power signal sent by a driving power supply and output a driving signal according to the power signal and the first level signal. Through the above embodiments, the problem of high cost in the prior art by driving the switching circuit through a driving chip is solved.

Description

Technical Field

[0001] This application relates to the field of circuits, and more specifically, to a drive circuit and a battery pack. Background Technology

[0002] In current energy storage solutions, the number of battery cells in a single system is enormous, ranging from hundreds to thousands. This inevitably leads to challenges due to uneven self-discharge rates caused by individual differences between battery cells, severely impacting the overall system performance consistency. Given the stringent requirements of energy storage applications for maximum system storage capacity and long-term service life, the implementation of balancing strategies becomes particularly important. The core objective is to optimize the balance between battery cells and improve overall efficiency. Currently, two main balancing methods are used in the market: passive balancing and active balancing.

[0003] Passive balancing schemes, due to their low heat dissipation efficiency and strategic limitations, are no longer adequate for the high-capacity battery cell requirements in the energy storage field. In contrast, active balancing strategies, by integrating transformers and switching circuits, effectively promote the redistribution of energy among battery cells, demonstrating a wider range of application prospects. In active balancing architectures, energy transfer requires transformers and switching circuits, making the driving of the switching circuits crucial. Currently, the mainstream method for driving these switching circuits is the use of dedicated MOS driver chips, but these chips are costly.

[0004] There is currently no effective solution to the problem of high cost associated with driving switch matrices using driver chips in existing technologies.

[0005] Therefore, it is necessary to improve the relevant technology to overcome the aforementioned defects. Utility Model Content

[0006] This application provides a driving circuit and a battery pack to at least solve the problem of high cost in the prior art of driving a switch matrix by a driving chip.

[0007] According to one embodiment of this application, a driving circuit is provided, comprising: a first driving sub-circuit, and a second driving sub-circuit connected to the first driving sub-circuit, wherein the first driving sub-circuit is configured to receive a control signal sent by a battery management system and determine to output a first level signal according to the control signal; the second driving sub-circuit is configured to receive a power signal sent by a driving power supply and output a driving signal according to the power signal and the first level signal.

[0008] In an exemplary embodiment, the first driving sub-circuit includes a first resistor and a first transistor, wherein one end of the first resistor is connected to the battery management system, and the other end of the first resistor is connected to the base of the first transistor; the collector of the first transistor is connected to the second driving sub-circuit, and the emitter of the first transistor is grounded.

[0009] In one exemplary embodiment, the resistance value of the first resistor is less than or equal to a first preset resistance value, wherein the first preset resistance value... , The first preset resistance value, The voltage corresponding to the control signal. This is the voltage drop between the base and emitter of the first transistor. The base current of the first transistor.

[0010] In one exemplary embodiment, the second driving sub-circuit includes: a second resistor and a second transistor, wherein one end of the second resistor is connected to the driving power supply, and the other end of the second resistor is connected to the base of the second transistor and the collector of the first transistor; the collector of the second transistor is connected to the driving power supply, and the emitter of the second transistor is connected to a switching circuit.

[0011] In one exemplary embodiment, the resistance value of the second resistor is less than or equal to a second preset resistance value, wherein the second preset resistance value... , The second preset resistance value, The voltage corresponding to the power supply signal. The voltage drop between the base and emitter of the second transistor. This is the base current of the second transistor.

[0012] In one exemplary embodiment, the driving circuit further includes a discharge circuit connected to the first driving sub-circuit and the second driving sub-circuit.

[0013] In one exemplary embodiment, the discharge circuit includes a diode, wherein the cathode of the diode is connected to the collector of a first transistor in the first driving sub-circuit, and the anode of the diode is connected to the emitter of a second transistor in the second driving sub-circuit.

[0014] In one exemplary embodiment, the discharge circuit includes a switching device, wherein one end of the switching device is connected to the emitter of the first transistor of the first driving sub-circuit, and the other end of the switching device is connected to the other end of the second resistor of the second driving sub-circuit.

[0015] In one exemplary embodiment, the driving circuit further includes a switching circuit, wherein the switching circuit is configured to control the operating state of a target field-effect transistor in the switching circuit according to the driving signal, wherein the target field-effect transistor is a field-effect transistor connected to the battery to be balanced.

[0016] According to one embodiment of this application, a battery pack is provided, including: any of the above-described driving circuits, and a battery module connected to the driving circuit.

[0017] The driving circuit of this application includes: a first driving sub-circuit and a second driving sub-circuit connected to the first driving sub-circuit. The first driving sub-circuit is used to receive a control signal sent by a battery management system and determine an output first level signal based on the control signal. The second driving sub-circuit is used to receive a power signal sent by a driving power supply and output a driving signal based on the power signal and the first level signal. This embodiment of the application achieves the driving of the switching circuit at a lower cost by decomposing the circuit into two relatively simple sub-circuits (the first driving sub-circuit and the second driving sub-circuit), reducing the need for high-performance, high-cost integrated chips. Since the cost of discrete components is generally lower than that of dedicated chips, the high cost of driving a switching matrix using a driving chip can be solved. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a circuit diagram (a) of a driving circuit according to an embodiment of this application. Figure 2 This is a circuit diagram (II) of a driving circuit according to an embodiment of this application. Detailed Implementation

[0021] The embodiments of this application will be described in detail below with reference to the accompanying drawings and examples.

[0022] It should be noted that the terms "first," "second," etc., in the specification, claims, and drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0023] This embodiment provides a driving circuit. Figure 1 This is a circuit diagram (I) of the driving circuit according to an embodiment of this application, as follows: Figure 1 As shown, the circuit includes the following: A first driving sub-circuit 12, and a second driving sub-circuit 14 connected to the first driving sub-circuit, wherein... The first driving sub-circuit 12 is used to receive control signals sent by the battery management system and determine the output first level signal according to the control signals; The second driving sub-circuit 14 is used to receive the power signal sent by the driving power supply, and output the driving signal according to the power signal and the first level signal.

[0024] The driving circuit receives the control signal through the first driving sub-circuit and only needs to output the first level signal based on this signal, and generates the driving signal through the second driving sub-circuit based on the power supply signal and the first level signal.

[0025] It should be noted that the aforementioned driving power source can be a battery power source.

[0026] The circuit described above includes a first driving sub-circuit and a second driving sub-circuit connected to the first driving sub-circuit. The first driving sub-circuit receives a control signal from the battery management system and determines an output first-level signal based on the control signal. The second driving sub-circuit receives a power signal from the driving power supply and outputs a driving signal based on the power signal and the first-level signal. This embodiment of the application achieves lower cost by decomposing the circuit into two relatively simple sub-circuits (the first driving sub-circuit and the second driving sub-circuit), reducing the need for high-performance, high-cost integrated chips. Since discrete components are generally less expensive than dedicated chips, the high cost of driving a switch matrix using a driver chip can be solved.

[0027] Optionally, the first driving sub-circuit includes: a first resistor and a first transistor, wherein one end of the first resistor is connected to the battery management system, and the other end of the first resistor is connected to the base of the first transistor; the collector of the first transistor is connected to the second driving sub-circuit, and the emitter of the first transistor is grounded.

[0028] In this embodiment, a first driving sub-circuit is constructed using discrete components (a first resistor and a first transistor). The first resistor is a current-limiting resistor used to limit the current flowing into the base of the first transistor, preventing excessive current from damaging the transistor. By appropriately selecting the resistance value of the first resistor, it can be ensured that the first transistor is in a saturated conduction state when it receives a control signal.

[0029] One end of the first resistor is connected to the battery management system (BMS) to receive control signals from the BMS; the other end is connected to the base of the first transistor to transmit control signals to the first transistor to change its state.

[0030] The first transistor can be either an NPN or PNP type, the specific type determined by the logic level of the actual circuit and the power supply conditions. The first transistor can switch between cutoff and saturation conduction states based on the signal received at its base. When a control signal (high or low level, depending on the transistor type) reaches the base of the first transistor, the first transistor conducts, thereby connecting the path between the drive power supply and the second drive sub-circuit.

[0031] The base of the first transistor is connected to the battery management system through the first resistor, and the collector is connected to the second driver circuit to transmit or cut off the current; the emitter is grounded to provide a current loop, that is, in the on state, the collector current flows to the ground line through the collector-emitter loop, ensuring the effective conduction of the transistor.

[0032] When the BMS sends a high-level signal (for an NPN transistor), the signal is current-limited by the first resistor and reaches the base of the first transistor, turning it on. At this time, a low-impedance path is formed between the collector and emitter of the first transistor, sending the low-level signal to the second driver circuit, triggering the generation of subsequent drive signals.

[0033] When the BMS sends a low-level signal, the base voltage of the first transistor is insufficient to turn it on, causing the first transistor to turn off. At this time, the collector and emitter of the first transistor are disconnected, preventing current from flowing to the second driver circuit.

[0034] like Figure 2 As shown, the first transistor corresponds to Figure 2 Q1 in the first resistor corresponds to Figure 2 In the first resistor R1, the control signal enters the base 1 of the first transistor Q1. The emitter 4 of Q1 is grounded. The collector 3 of the first transistor Q1 and the base 2 of the second transistor are connected together.

[0035] In the embodiments of this application, the first driving sub-circuit is composed of discrete components (a first resistor and a first transistor), which reduces costs and improves the response speed of the circuit while meeting the driving requirements.

[0036] Optionally, the resistance value of the first resistor is less than or equal to a first preset resistance value, wherein the first preset resistance value... , The first preset resistance value, The voltage corresponding to the control signal. This is the voltage drop between the base and emitter of the first transistor. The base current of the first transistor.

[0037] It should be noted that to ensure the first transistor Q1 is in saturation operation, the base current (I0) of the transistor needs to be calculated. b1 ) and collector current (I c The value of the first resistor R1 directly affects the current flowing into the base of Q1, thus affecting whether the transistor can fully conduct to saturation. Therefore, it is necessary to calculate the critical value of the first resistor (i.e., the first preset resistance value), specifically: Step 1: Determine the base current I of the transistor b1 .

[0038] For the first transistor Q1 to enter saturation, the base current I... b1 It needs to be large enough that even the collector current I c When the transistor reaches its maximum value, V ce The collector-emitter voltage remains close to zero. Therefore, ,in, It is the base current under saturation. It is the collector current (which is usually determined by the load in saturation). This is the DC current gain of the first transistor in saturation. It should be noted that, in order to reliably drive the transistor to saturation, in practical applications, I is usually... b1 Much larger For example, I can be set b1 =10 .

[0039] Step 2: Calculate the critical value of the first resistor R1.

[0040] After determining the required base current I b1 In this case, the critical value of the first resistor R1 can be calculated using the following formula: , For silicon transistors It is approximately 0.6V to 0.7V.

[0041] To ensure that transistor Q1 is in saturation, the value of R1 should be less than or equal to the critical value.

[0042] Optionally, the second driving sub-circuit includes: a second resistor and a second transistor, wherein one end of the second resistor is connected to the driving power supply, and the other end of the second resistor is connected to the base of the second transistor and the collector of the first transistor; the collector of the second transistor is connected to the driving power supply, and the emitter of the second transistor is connected to the switching circuit.

[0043] In this embodiment, the circuit is constructed using discrete components (a second resistor and a second transistor). The second resistor is a current-limiting resistor used to limit the current flowing into the base of the second transistor, preventing excessive current from damaging the transistor. By appropriately adjusting the resistance value of the second resistor, the conduction level of the second transistor can be controlled, thereby adjusting the strength of the drive signal output to the switching circuit.

[0044] One end of the second resistor is connected to the driving power supply to obtain a stable voltage supply; the other end is simultaneously connected to the base of the second transistor and the collector of the first transistor Q1 in the first driving sub-circuit to receive the control signal transmitted from the first transistor Q1.

[0045] The second transistor can be either an NPN or PNP type, depending on the potential of the driving power supply and the input requirements of the switching circuit to be controlled. Under the current-limiting effect of the second resistor, the second transistor switches between cutoff and saturation conduction states according to the signal level (high or low) input from the first transistor. When the second transistor is in saturation conduction, it can transfer energy from the driving power supply to the switching circuit, activating the switch.

[0046] The base of the second transistor is connected to the collector of the first transistor Q1 through a second resistor to receive control signals; the collector is connected to the drive power supply to receive energy; and the emitter is connected to the switching circuit to convert the energy of the drive power supply into a drive signal output.

[0047] like Figure 2 As shown, the second resistor corresponds to Figure 2 R2 in the diagram corresponds to the second transistor. Figure 2 In the first transistor Q1, the collector of the second transistor Q2 is connected to the drive power input, and the drive power input is connected to the base 2 of the second transistor Q2 and the emitter 3 of the first transistor Q1 through the second resistor R2.

[0048] When the switch matrix needs to be turned off, the control signal is high, and the emitter 4 of the first transistor Q1 is grounded. When the first transistor Q1 is turned on, a low level is supplied to the base of the second transistor, and the second transistor is turned off. At this time, the base of the second transistor discharges through the first transistor, thereby turning off the matrix switch.

[0049] When the switch matrix needs to be driven, the control signal is low, and the first transistor Q1 is cut off. At this time, the power supply signal input to the drive power supply passes through the second resistor R2 to the base 2 of the second transistor Q2. The value of the second resistor R2 ensures that the second transistor Q2 is in the saturation region and is conducting. After the second transistor Q2 is turned on, the drive power supply input is output through the second transistor Q2 to drive the MOS switches, and then drive the matrix switches.

[0050] Optionally, the resistance value of the second resistor is less than or equal to a second preset resistance value, wherein the second preset resistance value... , The second preset resistance value, The voltage corresponding to the power supply signal. The voltage drop between the base and emitter of the second transistor. This is the base current of the second transistor.

[0051] The value of the second resistor R2 needs to ensure that the base current is large enough to keep transistor Q2 in the saturation region. The voltage supplied by the power supply signal is... Therefore, the maximum value of R² can be calculated using the following formula: ,in, It is the voltage drop between the base and emitter. For silicon transistors, the voltage drop is approximately 0.6V to 0.7V.

[0052] Optionally, the driving circuit further includes a discharge circuit connected to the first driving sub-circuit and the second driving sub-circuit, wherein the discharge circuit includes a diode, wherein the cathode of the diode is connected to the collector of the first transistor of the first driving sub-circuit, and the anode of the diode is connected to the emitter of the second transistor.

[0053] When driving switching devices such as MOSFETs in a switching circuit, the gate capacitance accumulates charge in the on-state. When a rapid turn-off of the MOSFET is required, this accumulated charge must be released quickly; otherwise, the MOSFET's turn-off time will be long, affecting the circuit's dynamic performance and efficiency. Therefore, a discharge circuit is used to provide a low-impedance discharge path when the MOSFET is turned off, ensuring that the gate charge dissipates rapidly.

[0054] Due to the unidirectional conductivity of a diode, it only conducts when the MOSFET is turned off and the gate charge needs to be released, thus forming a discharge path. The cathode of the diode is connected to the collector of the first transistor Q1 in the first driver circuit. When the first transistor Q1 is turned on and its collector potential is pulled low, the diode meets the conduction condition. At the same time, the anode of the diode is connected to the other end of the second resistor R2 in the second driver circuit (i.e., the emitter of the second transistor Q2), ensuring that when the second transistor Q2 is turned off, the charge on the MOSFET gate can be quickly discharged to the circuit ground through the diode.

[0055] like Figure 2 As shown, the second diode corresponds to Figure 2 In the circuit, diode D1 has its cathode connected to the collector 3 of the first transistor Q1, and its anode connected to the output of the drive power supply and the emitter 1 of the second transistor Q2.

[0056] Using diodes not only simplifies the circuit structure and reduces costs, but also ensures the rapid turn-off of MOSFETs.

[0057] Optionally, the discharge circuit includes a switching device, wherein one end of the switching device is connected to the emitter of the first transistor of the first driving sub-circuit, and the other end of the switching device is connected to the other end of the second resistor of the second driving sub-circuit.

[0058] Optionally, the switching device includes an electronic switch or a mechanical switch, which acts as a discharge circuit and activates the discharge function when turned off.

[0059] Electronic switches, such as MOSFETs, are typically controlled to turn on or off by changing the voltage on their gate. When a sufficiently high voltage is provided, the electronic switch is fully turned on; reducing the gate voltage below a threshold causes the electronic switch to turn off rapidly.

[0060] Mechanical switches are generally driven to open or close by electromagnetic or mechanical force. For example, relays achieve conduction or disconnection by using an electromagnet to attract contacts.

[0061] Optionally, the driving circuit further includes a switching circuit, wherein the switching circuit is used to control the operating state of the target field-effect transistor in the switching circuit according to the driving signal, wherein the target field-effect transistor is a field-effect transistor connected to the battery to be balanced.

[0062] A switching circuit receives drive signals from the second drive sub-circuit and controls the operating state of the target MOSFET accordingly. The target MOSFET is a transistor directly connected to the battery cell to be balanced; turning the transistor on or off achieves energy transfer or balancing between the battery cells.

[0063] The drive signal is typically a high- or low-level pulse signal used to indicate whether the target MOSFET should be turned on or off. The switching circuit interprets the received drive signal and controls the gate voltage of the target MOSFET accordingly. If the drive signal indicates on, the switching circuit raises the gate voltage to a level sufficient to turn on the MOSFET; if the signal indicates off, it lowers the gate voltage to the MOSFET's off level.

[0064] When the MOSFET is turned on, energy is allowed to flow between battery cells, achieving energy balance or redistribution; when the MOSFET is turned off, energy flow is prevented, maintaining the independent state of the battery cells.

[0065] In this embodiment, after power-on, the power management system controls the first transistor Q1 to conduct and the second transistor Q2 to be cut off, achieving active latch-up. This prevents malfunctions even with external interference, improving anti-interference capabilities. Furthermore, the diode D1 and the first transistor Q1 enable MOSFET gate discharge, reducing the MOSFET turn-off time. For example, with a MOSFET gate capacitance of 1nF and a discharge resistor of 10kΩ, the required discharge time is approximately 50µs. Using a diode can reduce this to 5ns, significantly decreasing the MOSFET turn-off time. This results in reduced MOSFET heat generation and increased lifespan. The extended MOSFET turn-off time also shortens the time required for active balancing channel switching, increasing the active balancing switching frequency.

[0066] Specific examples in this embodiment can be found in the examples described in the above embodiments and exemplary implementations, and will not be repeated here.

[0067] Obviously, those skilled in the art should understand that the modules or steps of this application described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. They can be implemented using computer-executable program code, and thus can be stored in a storage device for execution by a computing device. In some cases, the steps shown or described can be performed in a different order than those presented here, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, this application is not limited to any particular combination of hardware and software.

[0068] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the principles of this application should be included within the protection scope of this application.

Claims

1. A driving circuit, characterized in that, include: A first driving sub-circuit, and a second driving sub-circuit connected to the first driving sub-circuit, wherein... The first driving sub-circuit is used to receive control signals sent by the battery management system and determine the output first level signal according to the control signals; The second driving sub-circuit is used to receive the power signal sent by the driving power supply, and output a driving signal according to the power signal and the first level signal.

2. The circuit according to claim 1, characterized in that, The first driving sub-circuit includes: a first resistor and a first transistor, wherein, One end of the first resistor is connected to the battery management system, and the other end of the first resistor is connected to the base of the first transistor. The collector of the first transistor is connected to the second driver circuit, and the emitter of the first transistor is grounded.

3. The circuit according to claim 2, characterized in that, The resistance value of the first resistor is less than or equal to a first preset resistance value, wherein the first preset resistance value... , The first preset resistance value, The voltage corresponding to the control signal. This is the voltage drop between the base and emitter of the first transistor. The base current of the first transistor.

4. The circuit according to claim 2, characterized in that, The second driving sub-circuit includes: a second resistor and a second transistor, wherein, One end of the second resistor is connected to the driving power supply, and the other end of the second resistor is connected to the base of the second transistor and the collector of the first transistor. The collector of the second transistor is connected to the driving power supply, and the emitter of the second transistor is connected to the switching circuit.

5. The circuit according to claim 4, characterized in that, The resistance value of the second resistor is less than or equal to a second preset resistance value, wherein the second preset resistance value... , The second preset resistance value, The voltage corresponding to the power supply signal. The voltage drop between the base and emitter of the second transistor. This is the base current of the second transistor.

6. The circuit according to claim 1, characterized in that, The driving circuit further includes a discharge circuit connected to the first driving sub-circuit and the second driving sub-circuit.

7. The circuit according to claim 6, characterized in that, The discharge circuit includes: a diode, wherein, The cathode of the diode is connected to the emitter of the first transistor in the first driving sub-circuit, and the anode of the diode is connected to the other end of the second resistor in the second driving sub-circuit.

8. The circuit according to claim 6, characterized in that, The discharge circuit includes: a switching device, wherein, One end of the switching device is connected to the collector of the first transistor in the first driving sub-circuit, and the other end of the switching device is connected to the emitter of the second transistor in the second driving sub-circuit.

9. The circuit according to claim 1, characterized in that, The driving circuit further includes: a switching circuit, wherein... The switching circuit is used to control the operating state of the target field-effect transistor in the switching circuit according to the driving signal, wherein the target field-effect transistor is a field-effect transistor connected to the battery to be balanced.

10. A battery pack, characterized in that, include: The driving circuit according to any one of claims 1 to 9, and the battery module connected to the driving circuit.

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