Battery charging and discharging heating system

Abstract

The utility model discloses a battery charging and discharging heating system, which comprises a heating module, a heating control module and a temperature detection module, the corresponding end of the heating control module is electrically connected with the corresponding end of the heating module and the corresponding end of the temperature detection module. Wherein the heating control module is used for controlling the heating temperature of the heating module, and the temperature detection module is further electrically connected with the corresponding end of the heating module and used for detecting the heating temperature of the heating module and feeding back the heating temperature to the heating control module; the heating module comprises a charging and discharging heating circuit; the charging and discharging heating circuit comprises a battery pack, a heating sheet, a heating and charging control circuit and a charger; the corresponding end of the battery pack is electrically connected with the heating piece and the corresponding end of the charger, and the corresponding end of the heating and charging control circuit is electrically connected with the heating piece and the corresponding end of the heating control module.

Description

Technical Field

[0001] This utility model relates to the field of battery heating technology, and in particular to a battery charging and discharging heating system. Background Technology

[0002] Existing battery pack heating technologies suffer from problems such as high cost, high hardware requirements, high development costs, large energy loss, low efficiency, limited communication methods, poor heating temperature consistency, and low integration of various functions.

[0003] 1. Similar product types on the market:

[0004] 1) External blower heating:

[0005] ① This method requires careful design of the air ducts inside the battery pack, and the heating effect is relatively slow.

[0006] ② If the external blower heating method is not designed properly, it may also cause local areas to be continuously heated, resulting in excessively high local temperatures.

[0007] ③ The external blower has a large power output, which results in significant energy loss if the battery needs to be charged or discharged at a constant temperature.

[0008] ④ External blower equipment is generally large in size, taking up space in the battery pack and reducing the flexibility of the battery.

[0009] 2) Insulating flexible electric heating film:

[0010] ① The insulating flexible electric heating film needs to be in complete contact with the object being heated, which results in lower safety.

[0011] ② The surface is easily damaged by external forces such as scratches and impacts, which can easily cause cracking or short circuits. In addition, the heating temperature of the electric heating film is relatively high, and it is prone to aging, cracking, and hardening under prolonged high temperature.

[0012] ③ Insulating flexible electric heating films have high thermal efficiency, but their heating speed may not be as fast as some rapid heating devices, such as electric heaters. This means that in very cold environments, it may take longer to reach the ideal temperature.

[0013] ④ The cost of repair and replacement is high when a malfunction occurs. If the heating film is damaged, the entire heating unit may need to be replaced.

[0014] 2. The cost is too high, resulting in an excessively high price for the battery packs. In the highly competitive market for heating battery products such as lithium batteries or lead-acid batteries, there is no cost advantage.

[0015] 3. If the heating function is activated when the temperature is too low during discharge, the energy consumption of the heating plate during the heating process will not be measured, which will affect the battery pack's SOC measurement.

[0016] 4. The heating system is not intelligent enough; it cannot actively adjust the heating temperature when the temperature is too high or too low.

[0017] 5. The number of communication ports is small, the number of peripherals that can be connected is too small, and the expandability is poor.

[0018] 6. Currently, most heating plates adopt passive control by slave devices. When the main control module fails or malfunctions, the heating plate will also lose its function. Utility Model Content

[0019] In view of the problems existing in the prior art, this utility model provides a battery charging and discharging heating system.

[0020] To achieve the above objectives, the technical solution of this utility model is as follows:

[0021] This utility model provides a battery charging and discharging heating system, including: a heating module, a heating control module, and a temperature detection module;

[0022] The heating control module is electrically connected to the heating module and the temperature detection module respectively. The heating control module is used to control the heating temperature of the heating module, and the temperature detection module is also electrically connected to the heating module to detect the heating temperature and feed it back to the heating control module.

[0023] The heating module includes a charge-discharge heating circuit, which includes a battery pack, a heating element, a heating and charging control circuit, and a charger.

[0024] The corresponding terminals of the battery pack are electrically connected to the corresponding terminals of the heating element and the charger, respectively, and the corresponding terminals of the heating and charging control circuit are electrically connected to the corresponding terminals of the heating element and the heating control module, respectively.

[0025] Preferably, the battery charging and discharging heating system further includes a power supply circuit, which includes a 10.6V power supply circuit, a 5V power supply circuit, and a 3.3V power supply circuit, wherein the corresponding terminal of the 10.6V power supply circuit is electrically connected to the corresponding terminal of the heating and charging control circuit; and the corresponding terminals of the 5V power supply circuit and the 3.3V power supply circuit are electrically connected to the corresponding terminals of the heating control module.

[0026] Preferably, the heating control module includes an MCU and its peripheral circuits. The MCU is an AT32F425, and the MCU outputs a PWM signal through the PF0 pin to control the charging and discharging heating circuit.

[0027] Preferably, the battery charging and discharging heating system further includes a communication wake-up circuit, the corresponding terminals of which are electrically connected to the corresponding terminals of the main control module.

[0028] Preferably, the communication wake-up circuit includes a communication isolation chip IS3722 and a transceiver electrically connected to the corresponding terminal of the communication isolation chip IS3722; the corresponding terminal of the communication isolation chip IS3722 is electrically connected to the corresponding terminal of the MCU.

[0029] Preferably, the temperature detection module includes an NTC temperature probe for detecting the temperature of the heating element and converting the temperature signal into an electrical signal to be fed back to the MCU.

[0030] Preferably, the heating and charging control circuit includes a diode D14, a transistor Q12, a transistor Q11, a transistor Q9, a transistor Q10, a MOSFET, and a differential inverting amplifier U16; one end of the diode D14 is electrically connected to the heating element and the drain of the MOSFET, and the other end is electrically connected to the source of the MOSFET and the corresponding terminal of the differential inverting amplifier U16; the gate of the MOSFET is electrically connected to the emitter of the transistor Q9 and the emitter of the transistor Q10, the collector of the transistor Q10 is electrically connected to the emitter of the transistor Q11, and the collector of the transistor Q11 is electrically connected to the base of the transistor Q10, the base of the transistor Q9, the collector of the transistor Q9, the base of the transistor Q11, and the collector of the transistor Q12; the base of the transistor Q12 is electrically connected to the MCU and the emitter of the transistor Q12.

[0031] The technical solution of this utility model has the following beneficial effects:

[0032] This invention can monitor temperature changes in real time and adjust the heating temperature accordingly, protecting the battery so that it can charge and discharge normally under extreme low-temperature conditions, maintaining the battery in normal working condition, extending battery life, and improving battery charging and discharging efficiency.

[0033] In this invention, the heating plate's starting power comes from charging and discharging. When there is no charging or discharging activity, it can remain inactive to reduce energy consumption. During operation, it can determine the power supply to its communication and heating components based on the temperature. Furthermore, it can measure its own current consumption and send this data to the battery pack to help measure its state of charge (SOC). This design achieves a low-cost, low-power, high-safety, and controllable heating heating solution.

[0034] 1. It adopts a PTC constant temperature heating element, which uses semiconductor ceramic material and operates by utilizing the positive temperature coefficient effect of the material. When current passes through it, the resistance of the material increases with the temperature, thereby automatically reducing the current and achieving power self-limitation at steady-state temperature.

[0035] 2. The heating module is powered by the battery charger and the battery discharge circuit. It can actively turn on the heating during charging or discharging to prevent the heating module from failing to turn on in time due to battery pack failure.

[0036] 3. The heating plate measures its own current consumption when it starts working, and can send this information to the battery pack to help it accurately measure the SOC.

[0037] 4. PWM control is used to control the heating temperature and keep the battery temperature constant.

[0038] 5. Existing heating plates use passive slave control, only starting to heat when they receive a heating signal. This design adopts an active control charging and discharging method for the heating plate. When the temperature is too low, the charger powers the heating plate, which sends a signal to the battery pack to shut down the charging and discharging tubes. The heating plate first heats the battery, and when the battery temperature reaches a certain value, it sends a signal to open the charging and discharging tubes to begin charging and discharging. This prevents problems such as heating module failure and uncontrolled heating module due to the battery pack being in an uncertain state at low temperatures.

[0039] 6. Multiple external communication interfaces allow for the addition of external control or communication functions. For example, a CANBUS bus can be used for communication during the heating process, allowing devices such as the battery pack and charger to access the heating plate status, enabling multi-level, intelligent management.

[0040] 7. It adopts a low-power design. When the heating plate is not working, it can shut down all communication and control power of the heating plate and enter sleep mode to reduce the power consumption of the heating plate.

[0041] 8. Because the heating plate is equipped with an external NTC temperature sensor, the temperature can be quickly collected to determine whether the heating function is turned on or off.

[0042] 9. It can improve automated production operations, reduce product material costs, save labor costs, and enhance product quality.

[0043] 10. It can realize the production of heating plates using the full SMT surface mount technology, resulting in lower costs, better quality, reduced number of workers, and greater efficiency and environmental friendliness. Attached Figure Description

[0044] Figure 1 This is a control block diagram of the present invention;

[0045] Figure 1a , Figure 1b , Figure 1c for Figure 1 A partially enlarged schematic diagram;

[0046] Figure 2 This is a circuit diagram of the heating control module of this utility model;

[0047] Figure 3 This is a circuit diagram of the heating module of this utility model;

[0048] Figure 4 This is the circuit diagram of the power supply circuit of this utility model;

[0049] Figure 5 This is a circuit diagram of the communication wake-up circuit of this utility model. Detailed Implementation

[0050] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.

[0051] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0052] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0053] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0054] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0055] Reference Figures 1 to 5 This utility model provides a battery charging and discharging heating system, including: a heating module, a heating control module 600, and a temperature detection module 500;

[0056] The heating control module 600 is electrically connected to the heating module and the temperature detection module 500 respectively. The heating control module 600 is used to control the heating temperature of the heating module, and the temperature detection module 500 is also electrically connected to the heating module to detect the heating temperature of the heating module and feed it back to the heating control module.

[0057] The heating module includes a charge-discharge heating circuit, which includes a battery pack 100, a heating element 300, a heating and charging control circuit 200, and a charger 400.

[0058] The corresponding terminals of the battery pack 100 are electrically connected to the corresponding terminals of the heating element 300 and the charger 400, respectively, and the corresponding terminals of the heating and charging control circuit 200 are electrically connected to the corresponding terminals of the heating element 300 and the heating control module 600, respectively.

[0059] Reference Figure 4, the battery charge-discharge heating system further includes a power supply circuit 50, which includes a 10.6V power supply circuit, a 5V power supply circuit, and a 3.3V power supply circuit. The corresponding ends of the 10.6V power supply circuit are electrically connected to the corresponding ends of the heating and charging control circuit 200; the corresponding ends of the 5V power supply circuit and the 3.3V power supply circuit are electrically connected to the corresponding ends of the heating control module. Specifically, the power supply circuit of the heating plate system is provided by the charge-discharge positive pole P+. When there is a charge-discharge behavior, the VIN terminal of the 3.3V power supply circuit will respectively provide power VDD for U14 through a 5V voltage regulator and a 3.3V voltage regulator, and start the heating plate control module MCU. When there is a communication wake-up event, the high level of the MCU (U14) enables CVDD, Q2 and Q1 are turned on, the EN pin of U1 is enabled, and the DC-DC starts to work to supply power to the communication power supply VDD5V. At the same time, the VDD5V from the DC-DC power supply supplies power to the communication isolation power supply, which can avoid unstable power supply affecting communication; when CVDD is disabled at a low level, Q2 and Q1 are not turned on, and EN is disabled, and the communication power supply and the isolation power supply can be turned off at the same time. When U14 receives communication or detects that the temperature is too low, the high level enables CVDD, Q4 is turned on, the source electrode of the PMOS is pulled down, Vs-Vg<Vgs(th), Q3 is turned on, and VIN outputs 10.6V through the voltage regulator to supply power to the heating plate. When CVDD is disabled at a low level, Q3 is not turned on, and the heating plate power supply can be turned off. The advantage of this circuit design is that when heating is needed or not, a signal switch can be used to determine the power supply for heating and communication, which can realize the heating function at a low cost, and can reduce the energy loss when the heating plate is not in use, achieving low power consumption.

[0060] Refer to Figure 2 , the heating control module includes an MCU and its peripheral circuits. The model of the MCU is AT32F425, and the MCU outputs a PWM signal through the PF0 pin to control the charge-discharge heating circuit.

[0061] Function description: The MCU can output PWM through the PF0 pin to control the heating temperature of the heating module. An external CAN bus and serial port are provided, which can communicate with the outside world to help the external main module better control and understand the status information of the heating module. PWM control can effectively solve the problem that the heating control is not timely due to abnormal communication or communication delay of temperature information with the battery pack; the temperature detection module includes an NTC temperature probe, which is used to detect the temperature of the heating sheet and convert the temperature signal into an electrical signal and feedback it to the MCU. It has two NTC temperature probes, which can detect the temperature of the heating module, so that the heating module can quickly judge under constant temperature, low temperature and high temperature conditions.

[0062] Refer to Figure 5The battery charging and discharging heating system also includes a communication wake-up circuit 700, whose corresponding terminals are electrically connected to the corresponding terminals of the main control module. Further, the communication wake-up circuit 700 includes a communication isolation chip IS3722 and a transceiver electrically connected to the corresponding terminal of the communication isolation chip IS3722; the corresponding terminal of the communication isolation chip IS3722 is electrically connected to the corresponding terminal of the MCU. Specifically, U7 and U10 are CAN and 485 communication isolation chips, respectively, and U9 and U13 are CAN and 485 transceivers, respectively. These chips can convert logic level signals into differential signals to achieve communication isolation and participate in the bus arbitration process, ensuring that data collisions are avoided when multiple devices share the bus. Furthermore, a specific frame wake-up mechanism can reduce unnecessary frame listening, further reducing power consumption and extending device battery life. When CAN receives communication information, a voltage difference is generated between CANH and CANL, causing U8 to conduct. At this time, the source of Q5 is pulled high, resulting in the WAKE_UP pin being pulled low. When 485 receives communication information, a voltage difference is generated between B and A, causing U12 to conduct. At this time, the source of Q7 is pulled high, resulting in the WAKE_UP pin being pulled low. Both CAN and 485 signals will pull the WAKE_UP pin low, triggering an external interrupt event that wakes up U14. When U14 transmits data, TX is low, and the output of the NOT gate of U11 is high, pulling the RE and DE pins of U13 high and disabling the receive enable pin RE of U13. When receiving data, TX is high, and the output of the NOT gate of U11 is low, pulling the RE and DE pins of U13 low. This ensures that there is no interference while transmitting and receiving information.

[0063] Reference Figure 3The heating and charging control circuit 200 includes a diode D14, a transistor Q12, a transistor Q11, a transistor Q9, a transistor Q10, a MOSFET, and a differential inverting amplifier U16. One end of the diode D14 is electrically connected to the heating element and the drain of the MOSFET, and the other end is electrically connected to the source of the MOSFET and the corresponding terminal of the differential inverting amplifier U16. The gate of the MOSFET is electrically connected to the emitter of the transistor Q9 and the emitter of the transistor Q10. The collector of the transistor Q10 is electrically connected to the emitter of the transistor Q11. The collector of the transistor Q11 is electrically connected to the base of the transistor Q10, the base of the transistor Q9, the collector of the transistor Q9, the base of the transistor Q11, and the collector of the transistor Q12. The base of the transistor Q12 is electrically connected to the MCU and the emitter of the transistor Q12. Specifically, D14 is a TVS diode. When a TVS diode is subjected to a sudden high-energy surge, it changes its impedance from high to low within ps seconds to absorb a large instantaneous current and clamps the voltage across it to a predetermined value. This protects downstream precision components from transient high-voltage spikes. For example, during braking, a large amount of energy flows back, requiring a D14 TVS diode to discharge this energy and protect internal components from damage. The heating element 300 uses a PTC (Positive Temperature Coefficient) constant-temperature heating element. At room temperature, this material has low resistance, generating heat when current flows through it. As the temperature rises, its resistance increases sharply, limiting current flow and reducing heat generation. When the temperature decreases, the resistance decreases, the current increases, and heat generation increases accordingly. This positive feedback mechanism allows the PTC constant-temperature heating element to automatically adjust and maintain a constant temperature within a certain range.

[0064] In the circuit, the positive terminal of heating element 300 is connected to P+ / C+, and the negative terminal is connected to the negative terminal of the heating plate. This allows control of the heating element 300's heating by controlling the on / off state of the negative terminal circuit. When U14 simultaneously enables the PWM output of the CHOT_PWM pin and the CVDD enable in the 10.6V power supply circuit, a high PWM output turns on Q12, Q11, Q9, and Q10, turning on the MOSFET and activating the negative terminal of heating element 300, initiating heating. A low PWM output turns off Q12, Q11, Q9, and Q10, turning off the MOSFET and stopping heating. Gradually increasing the PWM output frequency increases the MOSFET switching frequency, extending the heating time of the heating plate; conversely, decreasing the PWM output frequency slows down the MOSFET switching frequency, reducing the heating time. This configuration allows control of the heating element's temperature through the PWM output frequency controlled by U14.

[0065] When the charger 400 is connected or discharging, and the temperature is low, the heating plate can control switch S1 to turn off. U14 sends a message to the battery pack 100 to turn off the charging / discharging tube, and the charger 400 supplies power to heat the battery pack. When the temperature of the battery pack 100 reaches the threshold, a message to turn on the charging / discharging of the battery pack 100 is sent, switch S1 turns on, and charging of the battery pack 100 begins. When the temperature reaches about 30°C or the high-temperature heating stop threshold is reached, heating is turned off or constant-temperature heating is determined according to the ambient temperature. When the temperature is detected to be below 5°C during discharge or a low-temperature heating threshold is set, the heating plate automatically turns on.

[0066] When heating is in progress, the current consumed by the heating system flows into R17 and R38. After integration by R47 and R48, the voltage is amplified by a differential inverting amplifier with a gain of AV = (20KF / 1KF) = 20. The voltage across R17 and R38 is then amplified and obtained by U14. The current consumed by the heating module is then calculated and sent to the battery pack to help accurately measure the SOC.

[0067] This design allows the heating plate to automatically identify the temperature and heat the battery pack when it cannot be turned on or function properly in low-temperature conditions. This avoids the risk that the internal chemical reaction of the battery will slow down and the internal resistance will gradually increase in low-temperature conditions, which could lead to the battery being unable to charge or causing a fire due to direct charging.

[0068] The technical solution of this utility model has the following beneficial effects:

[0069] This technical solution uses a positive temperature coefficient PTC constant temperature heating element, which can gradually increase its own resistance as the heating temperature rises, limiting the increase of current, reducing its own heat generation, and avoiding continuous heating in the state of control system failure, which could cause safety accidents such as battery pack fire.

[0070] This technology can monitor temperature changes in real time and adjust the heating temperature accordingly to protect the battery from extreme low-temperature conditions, ensuring normal charging and discharging and maintaining the battery in normal operating condition. This can extend battery life and improve battery charging and discharging efficiency.

[0071] This solution features an external communication interface, greatly facilitating the control and communication of the heating plate. For example, when the charger is connected, it can communicate with the heating plate and battery to determine the battery pack temperature status. Once the battery pack temperature returns to normal, charging begins. This avoids the battery pack failing to function properly at low temperatures. Direct charging at low temperatures could lead to fires or other safety issues due to the battery pack's high internal resistance at low temperatures. Furthermore, connecting the charger, heating plate, and battery pack to the same CANBUS bus reduces costs and provides a better solution for intelligent battery management.

[0072] In this technical solution, the heating plate's startup power comes from charging and discharging. When there is no charging or discharging activity, it can remain inactive to reduce energy consumption. During operation, it can determine the power supply for its communication and heating components based on the temperature. Furthermore, it can measure its own current consumption and send this data to the battery pack to help measure the State of Charge (SOC). This achieves a heating plate design that is low-cost, low-power, highly safe, and provides controllable heating.

[0073] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made under the inventive concept of the present utility model using the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A battery charging and discharging heating system, characterized in that, include: Heating module, heating control module, temperature detection module; The heating control module is electrically connected to the heating module and the temperature detection module respectively. The heating control module is used to control the heating temperature of the heating module, and the temperature detection module is also electrically connected to the heating module to detect the heating temperature and feed it back to the heating control module. The heating module includes a charge-discharge heating circuit, which includes a battery pack, a heating element, a heating and charging control circuit, and a charger. The corresponding terminals of the battery pack are electrically connected to the corresponding terminals of the heating element and the charger, respectively, and the corresponding terminals of the heating and charging control circuit are electrically connected to the corresponding terminals of the heating element and the heating control module, respectively.

2. The battery charging and discharging heating system according to claim 1, characterized in that, The battery charging and discharging heating system also includes a power supply circuit, which includes a 10.6V power supply circuit, a 5V power supply circuit, and a 3.3V power supply circuit. The corresponding terminal of the 10.6V power supply circuit is electrically connected to the corresponding terminal of the heating and charging control circuit. The corresponding terminals of the 5V power supply circuit and the 3.3V power supply circuit are electrically connected to the corresponding terminals of the heating control module.

3. The battery charging and discharging heating system according to claim 1, characterized in that, The heating control module includes an MCU and its peripheral circuits. The MCU is an AT32F425. The MCU outputs a PWM signal through the PF0 pin to control the charging and discharging heating circuit.

4. The battery charging and discharging heating system according to claim 1, characterized in that, The battery charging and discharging heating system also includes a communication wake-up circuit, the corresponding terminals of which are electrically connected to the corresponding terminals of the main control module.

5. The battery charging and discharging heating system according to claim 4, characterized in that, The communication wake-up circuit includes a communication isolation chip IS3722 and a transceiver electrically connected to the corresponding terminal of the communication isolation chip IS3722; the corresponding terminal of the communication isolation chip IS3722 is electrically connected to the corresponding terminal of the MCU.

6. The battery charging and discharging heating system according to claim 3, characterized in that, The temperature detection module includes an NTC temperature probe, which is used to detect the temperature of the heating element and convert the temperature signal into an electrical signal to be fed back to the MCU.

7. The battery charging and discharging heating system according to claim 3, characterized in that, The heating and charging control circuit includes diode D14, transistors Q12, Q11, Q9, Q10, a MOSFET, and a differential inverting amplifier U16. One end of diode D14 is electrically connected to the heating element and the drain of the MOSFET, and the other end is electrically connected to the source of the MOSFET and the corresponding terminal of the differential inverting amplifier U16. The gate of the MOSFET is electrically connected to the emitter of transistors Q9 and Q10, the collector of transistor Q10 is electrically connected to the emitter of transistor Q11, and the collector of transistor Q11 is electrically connected to the base of transistors Q10, Q9, Q9, Q11, and Q12. The base of transistor Q12 is electrically connected to the MCU and the emitter of transistor Q12.

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