Lithium battery power supply circuit and battery replacement cabinet

Abstract

The present application relates to the technical field of power supply circuit, and provides a lithium battery power supply circuit and a battery replacement cabinet, the power supply circuit comprises a driving switch circuit, a current sampling circuit, a voltage detection circuit, an environment sampling circuit and a power supply control circuit, the driving switch circuit comprises an H-bridge structure composed of a first switch bridge arm and a second switch bridge arm, and an excitation coil of a relay is connected in cross between the midpoints of the first switch bridge arm and the second switch bridge arm; the power supply control circuit is electrically connected with the driving switch circuit, the current sampling circuit, the voltage detection circuit and the environment sampling circuit respectively, the power supply control circuit adjusts the duty cycle of a driving pulse according to a loop current, a bus input voltage and an environment temperature, controls the on-off state of the first switch bridge arm and the second switch bridge arm through the driving pulse, adjusts the average driving current of the excitation coil, greatly reduces the steady-state power consumption and temperature rise of the coil, has high current control precision, and is suitable for the long-term operation scene of the battery replacement cabinet.

Description

Technical Field

[0001] This invention relates to the field of power supply circuit technology, and in particular to a lithium battery power supply circuit and a battery swapping cabinet. Background Technology

[0002] With the rapid upgrading of the new energy industry and the continuous expansion of the electric vehicle market, the demand for lithium battery replenishment has increased significantly. Battery swapping cabinets, as efficient and convenient battery replenishment infrastructure, have been widely adopted and applied in new energy battery swapping scenarios. Each battery swapping cabinet integrates multiple independent charging compartments, each used to hold a lithium battery to be charged. Each compartment is equipped with a relay and a lithium battery power supply circuit. The lithium battery power supply circuit connects and disconnects the lithium battery through the on / off action of the relay.

[0003] In existing battery swapping cabinet charging systems, traditional lithium battery power supply circuits typically apply a constant voltage directly, resulting in high coil power consumption and severe heat generation during the relay holding phase. This not only wastes electrical energy but also accelerates coil insulation aging and reduces the lifespan of the battery swapping cabinet. Summary of the Invention

[0004] The purpose of this invention is to provide a lithium battery power supply circuit and a battery swapping cabinet, which aims to solve the technical problems of high power consumption and severe heat generation in existing lithium battery power supply circuits.

[0005] In a first aspect, this application provides a lithium battery power supply circuit, including: The driving switch circuit includes an H-bridge structure composed of a first switch bridge arm and a second switch bridge arm, and the excitation coil of the relay is connected across the midpoint between the first switch bridge arm and the second switch bridge arm. A current sampling circuit is used to collect the loop current of the excitation coil; A voltage detection circuit is used to detect the bus input voltage of the excitation coil; An environmental sampling circuit is used to collect the ambient temperature of the excitation coil; The power supply control circuit is electrically connected to the drive switch circuit, the current sampling circuit, the voltage detection circuit, and the environmental sampling circuit, respectively. The power supply control circuit adjusts the duty cycle of the drive pulse according to the loop current, the bus input voltage, and the ambient temperature, and controls the on / off state of the first switch bridge arm and the second switch bridge arm through the drive pulse, thereby adjusting the average drive current of the excitation coil.

[0006] The specific process is as follows: when the bus input voltage is greater than the preset starting voltage (e.g., 10 volts), it indicates that the charging compartment is powered on. Based on different bus input voltages and ambient temperatures, a set of correlations between ambient temperature and bus input voltage is pre-calibrated. The power supply control circuit determines the initial pull-in duty cycle required by the excitation coil at this time and adjusts the drive pulse to the corresponding initial pull-in duty cycle, allowing the excitation coil to quickly generate sufficient electromagnetic attraction to overcome air gap magnetic reluctance and mechanical resistance, ensuring reliable closure of the relay contacts. For example, if the bus input voltage is too low, the duty cycle is appropriately increased to compensate for insufficient voltage and ensure the average current of the excitation coil; conversely, the opposite is also true. For another example, if the ambient temperature rises, the internal resistance of the excitation coil increases, and the current decreases under the same bus input voltage; the duty cycle is then increased synchronously to offset the effect of temperature drift; conversely, the opposite is also true.

[0007] Considering the lag in the response of bus input voltage and ambient temperature, and that excitation action, load disturbance, and instantaneous interference can all cause loop current fluctuations, the loop current can respond instantaneously. Subsequently, using the loop current as feedback, the pull-in duty cycle is corrected in real time to eliminate static errors, suppress instantaneous current fluctuations, and lock the loop current within the pull-in target range.

[0008] After a preset engagement time period (e.g., 3 seconds), the relay has completed contact closure and automatically switches to the holding phase. At this time, based on different bus input voltages and different ambient temperatures, the power supply control circuit determines the initial holding duty cycle required by the excitation coil in the holding phase, and adjusts the drive pulse to the corresponding initial holding duty cycle to ensure that the loop current quickly approaches the holding target range. Subsequently, the holding duty cycle is adjusted in real time based on the instantaneous response loop current to lock the loop current within the holding target range.

[0009] The H-bridge structure has the ability to apply voltage in both directions. When the relay is turned off, it can achieve active freewheeling through reverse voltage, which greatly accelerates the decay speed of coil current, shortens the contact release time, and suppresses the generation of electric arc.

[0010] In one embodiment, the first switch bridge arm and the second switch bridge arm are respectively connected between the output terminal and the ground terminal of the power supply control circuit, and the input terminal and the output terminal of the excitation coil are respectively connected to the midpoint node of the first switch bridge arm and the second switch bridge arm.

[0011] In one embodiment, the first switch bridge arm includes a first power switch and a second power switch connected in series, and the input terminal of the excitation coil is connected to the connection node between the first power switch and the second power switch. The second switch bridge arm includes a third power switch and a fourth power switch connected in series, and the output terminal of the excitation coil is connected to the connection node between the third power switch and the fourth power switch.

[0012] In one embodiment, the power supply control circuit outputs four independent drive pulses to control the control electrodes of the first power switch, the second power switch, the third power switch, and the fourth power switch, respectively, so as to adjust the phase difference between the first switch arm and the second switch arm.

[0013] In one embodiment, the drive switch circuit further includes a resonant compensation circuit, and the H-bridge structure is connected to both ends of the excitation coil through the resonant compensation circuit.

[0014] In one embodiment, the resonant compensation circuit includes a resonant inductor, a first resonant capacitor, and a second resonant capacitor. The resonant inductor and the first resonant capacitor are connected in series between the midpoint of the first switch bridge arm and the input terminal of the excitation coil. One end of the second resonant capacitor is connected to the node between the resonant inductor and the first resonant capacitor, and the other end is connected between the midpoint of the second switch bridge arm and the output terminal of the excitation coil.

[0015] In one embodiment, the current sampling circuit includes a current sampling chip connected in series in the power supply circuit of the excitation coil. The current sampling chip has an I2C communication interface, and its SDA pin and SCL pin are connected to the corresponding communication pins of the power supply control circuit through a first current limiting resistor and a second current limiting resistor, respectively, to transmit current sampling data.

[0016] In one embodiment, the voltage detection circuit includes a second voltage divider resistor and a third voltage divider resistor connected in series. The second voltage divider resistor is connected to the bus input voltage, the third voltage divider resistor is grounded, and the connection node between the second voltage divider resistor and the third voltage divider resistor is connected to the power supply control circuit.

[0017] In one embodiment, the environmental sampling circuit includes a first voltage divider resistor and a thermistor connected in series, the connection node between the first voltage divider resistor and the thermistor is connected to the power supply control circuit, and the thermistor is grounded.

[0018] Secondly, this application provides a battery swapping cabinet, including the lithium battery power supply circuit described in any one of the above.

[0019] The beneficial effects of the lithium battery power supply circuit and battery swapping cabinet provided by this invention are as follows: After the relay enters the holding mode, this solution reduces the average current of the coil by lowering the duty cycle of the drive pulse, abandoning the traditional constant voltage full current power supply mode, significantly reducing the active power consumption of the coil, reducing heat generation from the source, and adapting to the scenario of long-term standby operation of the battery swapping cabinet. By combining the three parameters of voltage, current, and ambient temperature to coordinately adjust the duty cycle of the drive pulse, it can compensate for the current deviation caused by grid voltage fluctuations, coil temperature rise, and ambient temperature changes, stabilizing the circuit current within a narrow range and ensuring the stable engagement and holding state of the relay. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A schematic diagram of a lithium battery power supply circuit provided in an embodiment of the present invention; Figure 2 A circuit diagram of the drive switch circuit and current sampling circuit of the lithium battery power supply circuit provided in the embodiment of the present invention; Figure 3 A circuit diagram of a voltage detection circuit and a power supply control circuit for a lithium battery power supply circuit provided in an embodiment; Figure 4 This is a schematic diagram of another part of the power supply control circuit of the lithium battery power supply circuit provided in the embodiment. Figure 5 This is a waveform diagram of the first switch bridge arm. Figure 6 The waveform diagram for the second switch bridge arm is shown below. Figure 7 The waveform diagram for driving the switching circuit.

[0022] The following are the labeling elements in the figure: 100. Drive switch circuit; 110. First switch bridge arm; Q1. First power switch transistor; Q2. Second power switch transistor; 120. Second switch bridge arm; Q3. Third power switch transistor; Q4. Fourth power switch transistor; 130. Resonant compensation circuit; L2. Resonant inductor; C13. First resonant capacitor; C12. Second resonant capacitor; Ci. Bus filter capacitor; 200. Current sampling circuit; U6. Current sampling chip; R6. First current limiting resistor; R7. Second current limiting resistor; R1. First sampling resistor; R2. Second sampling resistor; R3, voltage divider sampling resistor; C10, signal filter capacitor; C6, first filter capacitor; C9, second filter capacitor; 300, voltage detection circuit; R8, second voltage divider resistor; R9, third voltage divider resistor; 400, environmental sampling circuit; R11, first voltage divider resistor; R10, thermistor; 500, power supply control circuit; U2, power supply control chip; C7, third filter capacitor; C8, fourth filter capacitor; U1, power management chip; D2, Zener diode; L1, power inductor; D1, freewheeling diode; 600, excitation coil. Detailed Implementation

[0023] Embodiments of the present invention are described in detail below, examples of which are illustrated 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 the present invention, and should not be construed as limiting the present invention.

[0024] Throughout this specification, references to "an embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of this application. Therefore, the phrases "in one embodiment" or "in some embodiments" appear in various places throughout the specification, and not all refer to the same embodiment. Furthermore, in one or more embodiments, particular features, structures, or characteristics may be combined in any suitable manner.

[0025] Furthermore, the terms "first," "second," etc., 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. Therefore, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature.

[0026] The charging bay operation of the battery swapping cabinet is as follows: the lithium battery power supply circuit relies on the opening and closing switching action of the relay to control the connection and disconnection between the power supply circuit and the lithium battery to be charged. When the driving voltage is applied to both ends of the relay excitation coil, the excitation coil is energized and forms an electromagnetic attraction. This electromagnetic force must overcome the internal air gap magnetic resistance and mechanical structural resistance of the relay to drive the internal contacts to complete the closing action. This process is the relay's energizing condition. After the contacts are fully closed and the circuit is connected, in order to prevent the contacts from springing back and becoming loose, the excitation coil needs to be continuously powered. Relying on the stable electromagnetic attraction, the contacts are kept in contact, allowing the relay to enter a steady-state holding condition. Among these, the structural resistance and magnetic reluctance loss that need to be overcome in the energizing condition are much greater than those in the steady-state holding condition. The current required in the energizing stage is greater than that required in the holding stage. It is not necessary to maintain a high current drive state throughout the entire process. Otherwise, the relay coil will consume a lot of power and generate a lot of heat in the holding stage, which not only wastes energy but also accelerates the aging of the coil insulation and reduces the service life of the battery swapping cabinet.

[0027] Example 1 Combination Figure 1 This application provides a lithium battery power supply circuit, including a drive switching circuit 100, a current sampling circuit 200, a voltage detection circuit 300, an environmental sampling circuit 400, and a power supply control circuit 500. The drive switching circuit 100 includes an H-bridge structure composed of a first switch arm 110 and a second switch arm 120, with the excitation coil 600 of a relay connected between the midpoints of the first and second switch arms 110 and 120. The current sampling circuit 200 is used to acquire the loop current of the excitation coil 600. The voltage detection circuit 300 is used to detect the bus input voltage V of the excitation coil 600. COIL HIGH The environmental sampling circuit 400 is used to collect the ambient temperature of the excitation coil 600.

[0028] The power supply control circuit 500 is electrically connected to the drive switch circuit 100, the current sampling circuit 200, the voltage detection circuit 300, and the environmental sampling circuit 400, respectively. The power supply control circuit 500 determines the power supply based on the loop current and the bus input voltage V. COIL HIGH Adjusting the duty cycle of the drive pulse according to the ambient temperature, the drive pulse controls the on / off state of the first switch arm 110 and the second switch arm 120, thereby adjusting the average drive current of the excitation coil 600.

[0029] The specific process is as follows: when the bus input voltage V COIL HIGH A voltage greater than the preset start-up voltage (e.g., 10 volts) indicates that the charging compartment is powered on. This varies depending on the bus input voltage V. COIL HIGH For different ambient temperatures, pre-calibrate a set of ambient temperature and bus input voltage V. COIL HIGHBased on the corresponding relationship, the power supply control circuit 500 determines the initial pull-in duty cycle required by the excitation coil 600 at this time, and adjusts the drive pulse to the corresponding initial pull-in duty cycle, allowing the excitation coil 600 to quickly generate sufficient electromagnetic attraction force to successfully overcome the air gap magnetic resistance and mechanical resistance, ensuring reliable closure of the relay contacts. For example, the bus input voltage V COIL HIGH If the voltage is too low, appropriately increase the duty cycle to compensate for insufficient voltage and ensure the average current of the excitation coil 600Ω; conversely, if the voltage is too high, the same applies. For example, as the ambient temperature increases, the internal resistance of the excitation coil 600Ω increases, resulting in a lower average current for the same bus input voltage V. COIL HIGH When the current decreases, the duty cycle is increased simultaneously to offset the effect of temperature drift; conversely, the same applies.

[0030] Considering the bus input voltage V COIL HIGH The response to ambient temperature is delayed, while excitation action, load disturbance, and instantaneous interference can all cause the loop current to jump. The loop current can respond instantaneously. Then, using the loop current as feedback, the pull-in duty cycle is corrected in real time to eliminate static errors, suppress instantaneous current fluctuations, and lock the loop current within the pull-in target range.

[0031] After a preset engagement time period (e.g., 3 seconds), the relay has completed contact closure and automatically switches to the holding phase. At this time, according to different bus input voltages V... COIL HIGH At different ambient temperatures, the power supply control circuit 500 determines the initial holding duty cycle required by the excitation coil 600 during the holding phase, and adjusts the drive pulse to the corresponding initial holding duty cycle to ensure that the loop current quickly approaches the holding target range. Then, using the instantaneous response loop current as feedback, the holding duty cycle is adjusted in real time to lock the loop current within the holding target range.

[0032] The H-bridge structure has the ability to apply voltage in both directions. When the relay is turned off, it can achieve active freewheeling through reverse voltage, which greatly accelerates the decay speed of coil current, shortens the contact release time, and suppresses the generation of electric arc.

[0033] Based on this, this solution reduces the average coil current by decreasing the drive pulse duty cycle after the relay enters the holding mode, abandoning the traditional constant voltage full current power supply mode, significantly reducing coil power consumption and heat generation, and adapting to scenarios where the battery swapping cabinet operates in standby mode for extended periods. Combined with the bus input voltage V... COIL HIGH The duty cycle of the drive pulse is adjusted in a coordinated manner by three parameters: circuit current, ambient temperature, and current. This can compensate for current deviations caused by grid voltage fluctuations, coil temperature rise, and ambient temperature changes, stabilizing the circuit current within the target range with minimal fluctuations, thus ensuring the relay stays engaged and in a stable state.

[0034] In some embodiments, combined with Figure 2The first switch arm 110 and the second switch arm 120 are respectively connected between the output terminal and the ground terminal of the power supply control circuit. The input terminal and the output terminal of the excitation coil 600 are respectively connected to the midpoint node of the first switch arm 110 and the second switch arm 120. By controlling the on / off timing of the first switch arm 110 and the second switch arm 120, the power supply control circuit 500 drives the pulse duty cycle and phase difference, thereby continuously adjusting the equivalent output voltage between the two midpoint nodes and precisely changing the average operating current of the excitation coil 600.

[0035] In one embodiment, combined Figure 2 The first switch arm 110 includes a first power switch Q1 and a second power switch Q2 connected in series. The input terminal of the excitation coil 600 is connected to the connection node between the first power switch Q1 and the second power switch Q2. The second switch arm 120 includes a third power switch Q3 and a fourth power switch Q4 connected in series. The output terminal of the excitation coil 600 is connected to the connection node between the third power switch Q3 and the fourth power switch Q4. By independently controlling the on and off states of the four power switches, different current decay modes can be provided for the excitation coil 600, thereby precisely controlling the mechanical action of the relay. For example, when it is necessary to disconnect the relay, the currently conducting diagonal power switch (such as the first power switch Q1 and the fourth power switch Q4) is turned off, and the other diagonal power switch (such as the second power switch Q2 and the third power switch Q3) is turned on. A reverse bus input voltage V is applied across the excitation coil 600. COIL HIGH The forced circuit current drops rapidly to zero in a very short time, greatly shortening the release time of the relay contacts and effectively suppressing the electric arc generated when the contacts are disconnected.

[0036] In one embodiment, combined Figure 2 and Figure 3 The power supply control circuit 500 outputs four independent drive pulses, which respectively control the control electrodes of the first power switch Q1, the second power switch Q2, the third power switch Q3, and the fourth power switch Q4 to adjust the phase difference θ between the first switch bridge arm 110 and the second switch bridge arm 120 (see...). Figure 7 ).

[0037] Figure 5 In the diagram, the control electrode voltages of the first power switch Q1 and the second power switch Q2 are denoted as V. Q1 V Q2 The two drive signals of the first switching bridge arm 110 are staggered by 180°, and the duty cycle of each power switch is 50%. 11 This is the midpoint potential of the first switch arm 110.

[0038] Figure 6In the middle, the control electrode voltages of the third power switch Q3 and the fourth power switch Q4 are V respectively. Q3 V Q4 The second switch arm 120 also adopts a drive method with 180° phase complementarity and a 50% fixed duty cycle. 12 This is the midpoint potential of the second switch arm 120.

[0039] Figure 7 In the middle, V 10 The output voltage of the H-bridge structure is given by parameter θ, which represents the phase offset between the two bridge arms. By adjusting the effective conduction time of the output voltage using the phase difference θ, dynamic control of the loop current can be achieved.

[0040] In one embodiment, combined Figure 2 The drive switching circuit 100 also includes a resonant compensation circuit 130, through which the H-bridge structure is connected to both ends of the excitation coil 600. Figure 5 If the first power switch Q1 is not completely turned off before the second power switch Q2 turns on prematurely, it will cause a direct short circuit in the first switch arm 110. The resonant compensation circuit 130 acts as an energy storage buffer. When the drive pulse of the first power switch Q1 drops to a low potential, the loop current is still relatively large. The resonant compensation circuit 130 stores this loop current, charging the parasitic capacitance of the first power switch Q1 and discharging the parasitic capacitance of the second power switch Q2. Similarly, when the drive pulse of the third power switch Q3 drops to a low potential, the resonant compensation circuit 130 charges the parasitic capacitance of the third power switch Q3 and discharges the parasitic capacitance of the fourth power switch Q4, thereby making V... 10 Stable change, that is Figure 7 Chinese V 10 The dashed line indicates that the current waveform output to the excitation coil 600 is smoother, which reduces external electromagnetic radiation and avoids sampling abnormalities or relay malfunctions caused by interference.

[0041] In one embodiment, combined Figure 2The resonant compensation circuit 130 includes a resonant inductor L2, a first resonant capacitor C13, and a second resonant capacitor C12. The resonant inductor L2 and the first resonant capacitor C13 are connected in series between the midpoint of the first switching bridge arm 110 and the input terminal of the excitation coil 600. One end of the second resonant capacitor C12 is connected to the node between the resonant inductor L2 and the first resonant capacitor C13, and the other end is connected between the midpoint of the second switching bridge arm 120 and the output terminal of the excitation coil 600. During the dead time of the switching transistor, the energy stored in the resonant inductor L2 charges and discharges the parasitic capacitance of the switching transistor, pulling the voltage across the switching transistor to 0, thereby achieving zero-voltage switching and significantly reducing switching losses. The resonant inductor L2 and the first resonant capacitor C13 form a series resonant branch, making the output current waveform smoother, providing an approximately sinusoidal current to the excitation coil 600, and reducing electromagnetic interference. The first resonant capacitor C13 also blocks the DC component in the output of the H-bridge structure, preventing DC current from flowing through the excitation coil 600, avoiding coil bias and uneven heating, and protecting the power switching transistor. The second resonant capacitor C12 is connected in parallel in the output circuit, which can absorb the instantaneous voltage spikes generated during the switching process, protect the excitation coil 600 and the downstream circuit, and reduce external electromagnetic radiation.

[0042] In one embodiment, the drive switching circuit 100 further includes a bus filter capacitor Ci, one end of which is connected to the output terminal of the power supply control circuit, and the other end is grounded. When the H-bridge structure high-frequency switch operates, it draws a large instantaneous current from the bus, and the bus filter capacitor Ci can quickly release energy.

[0043] In some embodiments, combined with Figure 2 The current sampling circuit 200 includes a current sampling chip U6 (optionally an INA226 chip). The current sampling chip U6 is connected in series in the power supply circuit of the excitation coil 600. The current sampling chip U6 has an I2C communication interface. Its SDA pin and SCL pin are connected to the corresponding communication pins of the power supply control circuit 500 through the first current limiting resistor R6 and the second current limiting resistor R7, respectively, to transmit current sampling data. The first current limiting resistor R6 and the second current limiting resistor R7 can limit the instantaneous inrush current of the I2C bus, preventing the communication pins from being damaged by surge current and electrostatic discharge. The current sampling chip U6 and the main control pins of the power supply control circuit 500 are also protected from overcurrent anomalies on the bus, improving the fault resistance of the communication link in the complex electrical environment of the battery swapping cabinet.

[0044] In one embodiment, combined Figure 2The current sampling circuit 200 includes a first sampling resistor R1 and a second sampling resistor R2. These two resistors are connected in series across the power supply circuit of the excitation coil 600, connecting the current path across the excitation coil 600 to the differential input terminal of the current sampling chip U6. The current sampling chip U6 then calculates the circuit current by measuring the differential voltage. Specifically, one end of the first sampling resistor R1 is connected to the first terminal of the excitation coil 600, and the other end is connected to the IN+ pin of the current sampling chip U6. One end of the second sampling resistor R2 is connected to the second terminal of the excitation coil 600, and the other end is connected to the IN- pin of the current sampling chip U6. Furthermore, the first sampling resistor R1 and the second sampling resistor R2 also limit the current flowing into the sampling pin of the current sampling chip U6, preventing damage to the chip from a sudden large current on the excitation coil 600 side.

[0045] Specifically, the current sampling circuit 200 includes a signal filtering capacitor C10, which is connected across the sampling output terminals of the first sampling resistor R1 and the second sampling resistor R2. The signal filtering capacitor C10 filters out high-frequency switching noise and spike interference in the excitation coil 600 circuit, making the sampling voltage waveform smoother; it also reduces the influence of the complex electromagnetic environment of the power swapping cabinet on the sampling signal, thereby improving the current sampling accuracy.

[0046] In one embodiment, combined Figure 2 The current sampling circuit 200 includes a voltage divider sampling resistor R3. One end of the voltage divider sampling resistor R3 is connected to the second terminal of the excitation coil 600, and the other end is connected to the VBUS pin of the current sampling chip U6. The VBUS pin samples the coil supply voltage through the chip's internal circuitry. Based on this, the voltage divider sampling resistor R3 proportionally divides the supply voltage on the coil side and sends it to the current sampling chip U6, enabling the chip to simultaneously acquire the circuit voltage and current, realize power calculation, and avoid damage to the chip from high voltage spikes.

[0047] Specifically, the current sampling circuit 200 includes a first filter capacitor C6. One end of the first filter capacitor C6 is connected to the power supply pin (VS pin) of the current sampling chip U6 and connected to the external power supply VIN, while the other end is grounded. The first filter capacitor C6 filters out high-frequency ripple and noise on the power supply line, providing a stable and low-noise operating power supply for the current sampling chip U6, reducing the impact of power supply voltage transients on the internal circuitry of the chip, and ensuring sampling accuracy.

[0048] Specifically, the current sampling circuit 200 includes a second filter capacitor C9. One end of the second filter capacitor C9 is connected to the VBUS pin of the current sampling chip U6, and the other end is grounded. The current sampling chip U6 filters out high-frequency interference and voltage ripple on the VBUS pin, stabilizes the voltage sampling signal, and makes the bus voltage acquired by the chip closer to the true value, providing reliable data for power calculation and overvoltage protection.

[0049] In this embodiment, the voltage detection circuit 300 can take many forms, such as obtaining the voltage after voltage division through a series voltage divider resistor, or obtaining the voltage through a dedicated ADC chip.

[0050] In some embodiments, combined with Figure 3 The voltage detection circuit 300 includes a second voltage divider resistor R8 and a third voltage divider resistor R9 connected in series. The second voltage divider resistor R8 is connected to the bus input voltage V. Coil High The third voltage divider resistor R9 is grounded, and the connection node between the second and third voltage divider resistors R8 and R9 is connected to the power supply control circuit 500. This voltage detection circuit 300 forms a voltage divider network using the second and third voltage divider resistors R8 and R9, converting the bus input voltage V... Coil High The voltage is proportionally reduced to within the range of the power supply control circuit 500, making it easier for the power supply control circuit 500 to sample the voltage and calculate the bus input voltage V using the voltage divider formula. Coil High The specific value is used to achieve the bus input voltage V. Coil High Real-time monitoring and closed-loop control.

[0051] In one embodiment, combined Figure 3 The environmental sampling circuit 400 includes a first voltage divider resistor R11 and a thermistor R10 connected in series. The connection node between the first voltage divider resistor R11 and the thermistor R10 is connected to the power supply control circuit 500, and the thermistor R10 is grounded. Changes in ambient temperature will change the resistance of the thermistor R10, thereby causing the voltage at the connection node of the first voltage divider resistor R11 and the thermistor R10 to change synchronously. By acquiring the voltage at this node, the power supply control circuit 500 can calculate the real-time ambient temperature of the excitation coil 600. The grounding of the thermistor R10 ensures a stable circuit reference potential, effectively suppressing common-mode interference and noise signals generated by the power circuit inside the battery swapping cabinet, avoiding temperature sampling signal drift and distortion, and ensuring accurate temperature data acquisition.

[0052] In some embodiments, combined with Figure 3 The power supply control circuit 500 includes a power supply control chip U2 (MCU), a third filter capacitor C7, and a fourth filter capacitor C8, which are connected in parallel. One end of the third filter capacitor C7 and the fourth filter capacitor C8 is connected to the power supply terminal VDD of the power supply control chip U2, and the other end is grounded. The 10μF third filter capacitor C7 solves the voltage drop caused by low-frequency ripple and load sudden changes; the 0.1μF fourth filter capacitor C8 solves the interference caused by high-frequency switching noise and spikes.

[0053] Specifically, the power supply control chip U2 has four output terminals, namely pins 2, 3, 8 and 9, which output four independent PWM signals to control four power switching transistors respectively.

[0054] In one embodiment, combined Figure 4 The power supply control circuit includes a power management chip U1, a power inductor L1, a freewheeling diode D1, and a Zener diode D2. The power management chip U1 controls the energy storage and release process of the inductor through the high-frequency switching of its internal switching transistor, achieving voltage reduction conversion. The freewheeling diode D1 provides a current freewheeling path for the power inductor L1, ensuring continuous current flow. The Zener diode D2 clamps the switching node voltage, suppressing voltage spikes. Based on this, the power supply provides the drive voltage Va to the driving switching circuit via the power management chip, freewheeling diode D1, and Zener diode D2.

[0055] Secondly, this application provides a battery swapping cabinet, including any of the above-mentioned lithium battery power supply circuits.

[0056] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A lithium battery power supply circuit, applied to the charging compartment of a battery swapping cabinet, characterized in that, include: The driving switch circuit includes an H-bridge structure composed of a first switch bridge arm and a second switch bridge arm, and the excitation coil of the relay is connected across the midpoint between the first switch bridge arm and the second switch bridge arm. A current sampling circuit is used to collect the loop current of the excitation coil; A voltage detection circuit is used to detect the bus input voltage of the excitation coil; An environmental sampling circuit is used to collect the ambient temperature of the excitation coil; The power supply control circuit is electrically connected to the drive switch circuit, the current sampling circuit, the voltage detection circuit, and the environmental sampling circuit. Based on the loop current, the bus input voltage, and the ambient temperature, the power supply control circuit adjusts the duty cycle of the drive pulse. The drive pulse controls the on / off state of the first and second switch arms, thereby adjusting the average drive current of the excitation coil. Specifically, when the bus input voltage is greater than a preset starting voltage, the power supply control circuit pre-calibrates a set of correspondences between ambient temperature and bus input voltage based on different bus input voltages and ambient temperatures. The power supply control circuit determines the initial pull-in duty cycle of the excitation coil and adjusts the drive pulse to the corresponding initial pull-in duty cycle. Then, using the loop current as feedback, it continuously corrects the pull-in duty cycle to lock the loop current within the target pull-in range. After a preset pull-in time period, the power supply control circuit adjusts the drive pulse to the initial holding duty cycle. Then, using the loop current as feedback, it continuously adjusts the holding duty cycle to lock the loop current within the target holding range. The current sampling circuit includes a current sampling chip connected in series in the power supply circuit of the excitation coil. The current sampling chip has an I2C communication interface, and its SDA pin and SCL pin are connected to the corresponding communication pins of the power supply control circuit through a first current limiting resistor and a second current limiting resistor, respectively, to transmit current sampling data. The current sampling circuit also includes a first sampling resistor and a second sampling resistor. One end of the first sampling resistor is connected to the first end of the excitation coil, and the other end is connected to the IN+ pin of the current sampling chip. One end of the second sampling resistor is connected to the second end of the excitation coil, and the other end is connected to the IN- pin of the current sampling chip.

2. The lithium battery power supply circuit according to claim 1, characterized in that: The first switch bridge arm and the second switch bridge arm are respectively connected between the output terminal and the ground terminal of the power supply control circuit, and the input terminal and the output terminal of the excitation coil are respectively connected to the midpoint node of the first switch bridge arm and the second switch bridge arm.

3. The lithium battery power supply circuit according to claim 2, characterized in that: The first switch bridge arm includes a first power switch and a second power switch arranged in series, and the input end of the excitation coil is connected to the connection node between the first power switch and the second power switch; The second switch bridge arm includes a third power switch and a fourth power switch connected in series, and the output terminal of the excitation coil is connected to the connection node between the third power switch and the fourth power switch.

4. The lithium battery power supply circuit according to claim 3, characterized in that: The power supply control circuit outputs four independent drive pulses, which respectively control the control electrodes of the first power switch, the second power switch, the third power switch, and the fourth power switch to adjust the phase difference between the first switch arm and the second switch arm.

5. The lithium battery power supply circuit according to claim 1, characterized in that: The drive switch circuit also includes a resonant compensation circuit, and the H-bridge structure is connected to both ends of the excitation coil through the resonant compensation circuit.

6. The lithium battery power supply circuit according to claim 5, characterized in that: The resonant compensation circuit includes a resonant inductor, a first resonant capacitor, and a second resonant capacitor. The resonant inductor and the first resonant capacitor are connected in series between the midpoint of the first switch bridge arm and the input terminal of the excitation coil. One end of the second resonant capacitor is connected to the node between the resonant inductor and the first resonant capacitor, and the other end is connected between the midpoint of the second switch bridge arm and the output terminal of the excitation coil.

7. The lithium battery power supply circuit according to any one of claims 1 to 6, characterized in that: The voltage detection circuit includes a second voltage divider resistor and a third voltage divider resistor connected in series. The second voltage divider resistor is connected to the bus input voltage, and the third voltage divider resistor is grounded. The connection node between the second voltage divider resistor and the third voltage divider resistor is connected to the power supply control circuit.

8. The lithium battery power supply circuit according to any one of claims 1 to 6, characterized in that: The environmental sampling circuit includes a first voltage divider resistor and a thermistor connected in series. The connection node between the first voltage divider resistor and the thermistor is connected to the power supply control circuit, and the thermistor is grounded.

9. A battery swapping cabinet, characterized in that: Includes the lithium battery power supply circuit as described in any one of claims 1 to 8.

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