Battery pack charging circuit and system

Abstract

The invention provides a battery pack charging circuit and system. The battery pack charging circuit comprises a voltage conversion circuit, a feedback circuit and a charging control circuit, the charging control circuit is connected with the battery pack; the feedback circuit is connected with the output end of the voltage conversion circuit; the charging control circuit is also connected with the feedback circuit; the voltage conversion circuit is connected with the charging control circuit and the battery pack. The current charging power is determined and the target charging power required by the battery pack is obtained by detecting the current charging voltage and the current charging current, and the charging voltage matched with the target charging power of the battery pack is output by adjusting the PWM driving signal. The charging voltage can be adjusted when the current charging voltage or charging current fluctuates, and damage to the battery pack is avoided.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery pack charging circuit and system. Background Art

[0002] In recent years, the battery industry has developed rapidly and battery technology has become more mature. Battery packs are widely used, especially in electric vehicles, and have been recognized by the public due to their advantages of low energy consumption and low cost.

[0003] The battery pack has limited storage capacity. After the power in the battery pack is consumed, the battery pack needs to be charged. The electrical parameters required for the battery pack charging process are usually standard parameters set in advance. However, in the actual charging process, there are fluctuations in the charging parameters, causing the actual charging parameters to not match the parameters required by the battery pack, causing damage to the battery pack. For example, fluctuations in the charging current or charging voltage may cause the battery pack to be overcharged.

[0004] The above contents are only used to assist in understanding the technical solution of the present application and do not constitute an admission that the above contents are prior art. Summary of the invention

[0005] The main purpose of the present application is to provide a battery pack charging circuit and system, aiming to solve the technical problem in the prior art that charging parameters fluctuate and cause damage to the battery pack.

[0006] To achieve the above object, the present application provides a battery pack charging circuit, the battery pack charging circuit comprising:

[0007] Voltage conversion circuit, feedback circuit and charging control circuit;

[0008] The charging control circuit is connected to the battery pack and is used to obtain the target charging power required by the battery pack;

[0009] The feedback circuit is connected to the output end of the voltage conversion circuit and is used to detect the current charging voltage and current input to the battery pack;

[0010] The charging control circuit is also connected to the feedback circuit, and is used to determine the current charging power according to the current charging voltage and the current charging current output by the feedback circuit, and to adjust the PWM driving signal output to the voltage conversion circuit according to the target charging power and the current charging power;

[0011] The voltage conversion circuit is connected to the charging control circuit and the battery pack, and is used to adjust the charging voltage output to the battery pack according to the adjusted PWM drive signal.

[0012] Optionally, the charging control circuit includes a controller and a logic operation chip;

[0013] The logic operation chip is connected to the feedback circuit, and is used to determine the current charging power according to the current charging voltage and the current charging current;

[0014] The controller is connected to the logic operation chip, the battery pack and the voltage conversion circuit, and is used to adjust the PWM drive signal output to the voltage conversion circuit according to the target charging power and the current charging power.

[0015] Optionally, the voltage conversion circuit includes: a buck circuit and / or a boost circuit;

[0016] The control end of the buck circuit is connected to the controller, the output end of the buck circuit is connected to the battery pack, and the input end of the buck circuit is connected to the power supply through an input port;

[0017] The buck circuit is used to step down the current charging voltage to obtain a step-down charging voltage according to the PWM driving signal adjusted by the controller during the step-down power supply process, and output the step-down charging voltage to the battery pack;

[0018] The control end of the boost circuit is connected to the controller, the output end of the boost circuit is connected to the battery pack, and the input end of the boost circuit is connected to the power supply through an input port;

[0019] The boost circuit is used to boost the current charging voltage to obtain a boosted charging voltage according to the adjusted PWM driving signal output by the controller during the boost power supply process, and output the boosted charging voltage to the battery pack.

[0020] Optionally, the voltage conversion circuit includes a switch tube and a transformer drawn with PCB copper foil;

[0021] The first end of the switch tube is connected to the controller, the second end of the switch tube is connected to the primary coil of the transformer, and the third end of the switch tube is connected to the power supply or ground; the secondary coil of the transformer is connected to the battery pack.

[0022] Optionally, the battery pack charging circuit further includes: a power request circuit;

[0023] The power request circuit is connected to the battery pack and connected to the controller via a CAN bus;

[0024] The power request circuit is used to obtain the current remaining power of the battery pack during the charging process of the battery pack, and determine the target charging power required by the battery pack according to the current remaining power.

[0025] Optionally, the battery pack charging circuit further includes: a UDS diagnostic circuit;

[0026] The UDS diagnostic circuit is connected to the controller, and is used to receive the current charging current and the current charging voltage output by the controller, and when the current charging voltage is greater than a preset voltage and / or the current charging current is greater than a preset current, feed back a fault signal to the controller;

[0027] The controller is further configured to stop outputting the PWM drive signal to the voltage conversion circuit when receiving the fault signal.

[0028] Optionally, the controller is also connected to the battery pack via a CAN bus to receive a battery temperature value output from the battery pack, and when the battery temperature value is greater than a preset temperature value, stops outputting the PWM drive signal to the voltage conversion circuit.

[0029] Optionally, the battery pack charging circuit further includes: a voltage stabilizing circuit;

[0030] The input end of the voltage stabilizing circuit is connected to the output end of the voltage conversion circuit, and the output end of the voltage stabilizing circuit is connected to the feedback circuit and the battery pack;

[0031] The voltage stabilizing circuit is used to stabilize the charging voltage output by the voltage conversion circuit, and output the stabilized charging voltage to the battery pack.

[0032] Optionally, the feedback circuit includes: a voltage feedback circuit and a current feedback circuit;

[0033] The voltage feedback circuit is connected to the output end of the voltage conversion circuit and is used to detect the current charging voltage input to the battery pack;

[0034] The current feedback circuit is connected to the output end of the voltage conversion circuit and is used to detect the current charging current input to the battery pack.

[0035] Optionally, the battery pack charging circuit further includes: a voltage amplification circuit and a current amplification circuit;

[0036] The voltage amplifying circuit is connected to the voltage feedback circuit and is used to amplify the current charging voltage output by the voltage feedback circuit;

[0037] The current amplifying circuit is connected to the current feedback circuit and is used to amplify the current charging current output by the current feedback circuit;

[0038] The charging control circuit is connected to the voltage amplifying circuit and the current amplifying circuit respectively, and is used to determine the current charging power according to the amplified current charging voltage and the amplified current charging current.

[0039] Optionally, the voltage amplification circuit includes: a first amplifier, a first resistor, a second resistor, a third resistor, a first capacitor and a second capacitor;

[0040] The first end of the first resistor is connected to the voltage feedback circuit and the first end of the first capacitor, the second end of the first resistor is connected to the positive input end of the first amplifier and the first end of the second capacitor; the first end of the second resistor is connected to the first end of the third resistor and the negative input end of the first amplifier, the second end of the third resistor is connected to the output end of the first amplifier; the second end of the second resistor, the second end of the first capacitor and the second end of the second capacitor are grounded;

[0041] The current amplifying circuit comprises: a second amplifier, a fourth resistor, a fifth resistor, a sixth resistor, a third capacitor and a fourth capacitor;

[0042] A first end of the fourth resistor is connected to the current feedback circuit and a first end of the third capacitor, and a second end of the fourth resistor is connected to a positive input end of the second amplifier and a first end of the fourth capacitor; a first end of the fifth resistor is connected to a first end of the sixth resistor and a negative input end of the second amplifier, and a second end of the sixth resistor is connected to an output end of the second amplifier; a second end of the fifth resistor, a second end of the third capacitor, and a second end of the fourth capacitor are grounded.

[0043] In addition, to achieve the above-mentioned purpose, the present application also provides a battery pack charging system, including an input port, an output port and the battery pack charging circuit, the battery pack charging circuit is connected to the power supply through the input port, and the battery pack charging circuit is connected to the battery pack through the output port.

[0044] The present application provides a battery pack charging circuit and system, the battery pack charging circuit includes: a voltage conversion circuit, a feedback circuit and a charging control circuit; the charging control circuit is connected to the battery pack to obtain the target charging power required by the battery pack; the feedback circuit is connected to the output end of the voltage conversion circuit to detect the current charging voltage and the current charging current input to the battery pack; the charging control circuit is also connected to the feedback circuit to determine the current charging power according to the current charging voltage and the current charging current output by the feedback circuit, and adjust the PWM drive signal output to the voltage conversion circuit according to the target charging power and the current charging power; the voltage conversion circuit is connected to the charging control circuit and the battery pack to adjust the charging voltage output to the battery pack according to the adjusted PWM drive signal. The present application determines the current charging power and obtains the target charging power required by the battery pack by detecting the current charging voltage and the current charging current, and outputs a charging voltage that matches the target charging power of the battery pack by adjusting the PWM drive signal, so that the charging voltage can be adjusted when the current charging voltage or charging current fluctuates to avoid damage to the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a schematic structural diagram of the first embodiment of the battery pack charging circuit of the present application;

[0046] Figure 2 This is a first structural schematic diagram of a second embodiment of a battery pack charging circuit of the present application;

[0047] Figure 3 A second structural schematic diagram of a second embodiment of a battery pack charging circuit of the present application;

[0048] Figure 4 This is a third structural schematic diagram of the second embodiment of the battery pack charging circuit of the present application;

[0049] Figure 5 This is a schematic structural diagram of a third embodiment of a battery pack charging circuit of the present application;

[0050] Figure 6 This is a schematic structural diagram of a fourth embodiment of a battery pack charging circuit of the present application;

[0051] Figure 7 A circuit schematic diagram of a voltage amplifying circuit and a current amplifying circuit in a fourth embodiment of a battery pack charging circuit of the present application;

[0052] Figure 8 This is a schematic diagram of the circuit principle structure of the battery pack charging circuit of this application.

[0053] Description of reference numerals:

[0054] 10, voltage conversion circuit; 20, feedback circuit; 30, charging control circuit; 301, controller; 302, logic operation chip; 101, buck circuit; 102, boost circuit; Q, switch tube; T, transformer; 50, UDS diagnostic circuit; 60, voltage stabilization circuit; 701, voltage amplifier circuit; 702, current amplifier circuit; A1, first operational amplifier; A2, second operational amplifier; R1, first resistor; R2, second resistor; R3, third resistor; R4, fourth resistor; R5, fifth resistor; R6, sixth resistor;

[0055] C1, first capacitor; C2, second capacitor; C3, third capacitor; C4, fourth capacitor; VCC, power supply; GND, ground.

[0056] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0057] It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0058] Reference Figure 1 , Figure 1 This is a schematic diagram of the structure of the first embodiment of the battery pack charging circuit of this application. Figure 1 A first embodiment of a battery pack charging circuit of the present application is provided.

[0059] In this embodiment, the battery pack charging circuit includes: a voltage conversion circuit 10, a feedback circuit 20 and a charging control circuit 30;

[0060] The charging control circuit 30 is connected to the battery pack and is used to obtain the target charging power required by the battery pack; the feedback circuit 20 is connected to the output end of the voltage conversion circuit 10 and is used to detect the current charging voltage and the current charging current output by the voltage conversion circuit 10; the charging control circuit 30 is also connected to the feedback circuit 20 and is used to determine the current charging power according to the current charging voltage and the current charging current output by the feedback circuit 20, and adjust the PWM drive signal output to the voltage conversion circuit 10 according to the target charging power and the current charging power; the voltage conversion circuit 10 is connected to the charging control circuit 30 and the battery pack and is used to adjust the charging voltage output to the battery pack according to the adjusted PWM drive signal.

[0061] It should be understood that the battery pack needs a power supply during the charging process. The power supply can be a charging pile or a mains electricity. Usually, there may be a mismatch between the power supply voltage output by the power supply and the charging voltage required by the battery pack. It is necessary to convert the power supply voltage output by the power supply into the charging voltage required for the battery pack when charging. The voltage conversion circuit 10 is a circuit for converting the power supply voltage output by the power supply into the charging voltage required by the battery pack. The voltage conversion circuit 10 can adjust the specific data of the voltage. The voltage conversion circuit 10 can be composed of a switching power supply chip and a peripheral structure, or other voltage conversion structures, such as a transformer, can be used. During the charging process, in order to determine the charging voltage, charging current and other parameters output to the battery pack, the voltage and current at the output end of the voltage conversion circuit 10 can be collected by setting a feedback circuit 20. The feedback circuit 20 is mainly used to collect parameters such as the charging voltage and charging current input to the battery pack. The feedback circuit 20 can adopt a sampling chip, a sampling resistor set in series and parallel, and other structures. The charging control circuit 30 is a circuit for controlling the charging voltage output by the voltage conversion circuit 10. The charging control circuit 30 can output PWM driving signals with different duty cycles, thereby controlling the voltage conversion process of the voltage conversion circuit 10 and adjusting the charging voltage.

[0062] It should be noted that the target charging power is the charging power required by the battery pack during the charging process, and the target charging power is related to the stage of the battery pack charging process and the remaining power in the battery pack. For example, when the remaining power of the battery pack is low, in order to speed up the charging rate, the target charging power required by the battery pack is large; and when the remaining power of the battery pack is sufficient or the charging process is about to end, in order to prevent the process and the accuracy of charging, the target charging power required by the battery pack is small. The current charging voltage and the current charging current are the voltage and current output to the battery pack by the voltage conversion circuit 10 at the current moment, that is, there may be fluctuations or abnormal voltages and currents. The current charging power is the power input to the battery pack at the current moment. In the absence of fluctuations in voltage, current, etc., the current charging power is the same as the target charging power required by the battery pack. The PWM drive signal is a signal used to control the working state of the voltage conversion circuit 10. The duty cycle of the PWM drive signal is different, and the working time of the voltage conversion circuit 10 is also different, and the charging voltage finally output to the battery pack will be different.

[0063] In the specific implementation process, in order to avoid the damage to the battery pack caused by the fluctuation of the charging voltage or the charging current, the target charging power currently required by the battery pack is obtained through the charging control circuit 30 connected to the battery pack, and then the current charging voltage and the current charging current currently input to the battery pack are collected by using the feedback circuit 20; the charging control circuit 30 can determine the current charging power currently input to the battery pack according to the current charging voltage and the current charging current, and then compare the current charging power with the target charging power. When the difference between the two exceeds the allowable error range, the PWM drive signal is adjusted according to the difference between the target charging power and the current charging power, or a new PWM drive signal is directly generated, and the working state of the voltage conversion circuit 10 is adjusted by using the PWM drive signal, and the charging voltage input to the battery pack is adjusted, so as to achieve that the power input to the battery pack matches the target charging power required by the battery pack.

[0064] The present application provides a battery pack charging circuit, which includes: a voltage conversion circuit 10, a feedback circuit 20 and a charging control circuit 30; the charging control circuit 30 is connected to the battery pack to obtain the target charging power required by the battery pack; the feedback circuit 20 is connected to the output end of the voltage conversion circuit 10 to detect the current charging voltage and the current charging current output by the voltage conversion circuit 10; the charging control circuit 30 is also connected to the feedback circuit 20 to determine the current charging power according to the current charging voltage and the current charging current output by the feedback circuit 20, and adjust the PWM drive signal output to the voltage conversion circuit 10 according to the target charging power and the current charging power; the voltage conversion circuit 10 is connected to the charging control circuit and the battery pack to adjust the charging voltage output to the battery pack according to the adjusted PWM drive signal. The present application determines the current charging power and obtains the target charging power required by the battery pack by detecting the current charging voltage and the current charging current, and outputs a charging voltage that matches the target charging power of the battery pack by adjusting the PWM drive signal. The charging voltage can be adjusted when the current charging voltage or charging current fluctuates to avoid damage to the battery pack.

[0065] Reference Figure 2 , Figure 2 The first structural diagram of the second embodiment of the battery pack charging circuit of the present application is shown in FIG. The second embodiment of the battery pack charging circuit of the present application is proposed based on the above first embodiment.

[0066] In this embodiment, the charging control circuit 30 includes a controller 301 and a logic operation chip 302;

[0067] The logic operation chip 302 is connected to the feedback circuit 20, and is used to determine the current charging power according to the current charging voltage and the current charging current;

[0068] The controller 301 is connected to the logic operation chip 302, the battery pack and the voltage conversion circuit 10, and is used to adjust the PWM drive signal output to the voltage conversion circuit according to the target charging power and the current charging power.

[0069] The controller 301 may be a body controller in the vehicle, or a BMS controller, and the controller 301 is mainly used to control the charging process of the battery pack. The logic operation chip 302 is a chip used to perform logic operations on the collected charging parameters, for example, the charging current can be calculated according to the charging voltage, and the charging power can be calculated.

[0070] In this embodiment, the current charging power can be calculated by the logic operation chip 302, and then the voltage conversion circuit 10 can be controlled by the controller 301. The controller 301 can establish a connection with the battery pack through the CAN bus, and the relevant structure inside the battery pack feeds back the target charging power to the controller 301 through the CAN bus.

[0071] It is understandable that, during the connection between the controller 301 and the battery pack, the controller in the battery pack can send the target charging power directly to the controller 301, or the controller 301 can output relevant instructions to the battery pack, and the battery pack will feedback the target charging power upon receiving the instruction.

[0072] Furthermore, when the required target power cannot be determined within the battery pack, a power request circuit 40 may be provided in the present application, which may calculate the target charging power required by the battery pack based on parameters such as the current voltage and remaining power displayed by the battery pack.

[0073] During the setting process, one end of the power request circuit 40 is connected to the battery pack, and the other end is connected to the controller 301 via the CAN bus.

[0074] During the process of acquiring the target charging power, the remaining power of the battery pack will cause the battery pack charging to be in different stages. For example, when the remaining power of the battery pack is very low, the battery pack is in a high-power fast charging stage; when the remaining power of the battery pack is high, the battery pack is in a low-power slow charging stage. The power request circuit 40 can obtain the current remaining power of the battery pack during the battery pack charging process, and determine the target charging power required for the battery pack based on the current remaining power. For example, when the remaining power of the battery pack is less than 10%, the power request circuit 40 can determine that the battery pack needs to be charged with the maximum charging power; and when the charging power of the battery pack is greater than 95%, the power request circuit 40 can determine that the battery pack needs to be charged with a smaller charging power. Of course, different charging powers can also be determined according to the specific value of the remaining power of the battery pack.

[0075] Reference Figure 3 , Figure 3 This is a second structural schematic diagram of the second embodiment of the battery pack charging circuit of the present application.

[0076] It should be understood that there are many structures that can realize the voltage conversion function, and different structures can be selected in this application to realize the voltage conversion function. When using a step-up / step-down circuit for voltage conversion, the voltage conversion circuit 10 may include: a buck circuit 101 and / or a boost circuit 102.

[0077] When the power supply voltage output by the power supply VCC is greater than the charging voltage required by the battery pack or the charging voltage needs to be stepped down, a buck circuit 101 can be set, wherein the control end of the buck circuit 101 is connected to the controller 301, the output end of the buck circuit 101 is connected to the battery pack, and the input end of the buck circuit 101 is connected to the power supply VCC through an input port.

[0078] It should be understood that the buck circuit is a circuit for reducing the input voltage. The buck circuit mainly reduces the power supply voltage input by the power supply VCC through the synergy of the energy storage structure and the switch structure.

[0079] During the step-down power supply process, the buck circuit 101 can step down the current charging voltage according to the adjusted PWM driving signal output by the controller 301 to obtain a step-down charging voltage, and output the step-down charging voltage to the battery pack.

[0080] When the power supply voltage output by the power supply VCC is lower than the charging voltage required by the battery pack or the charging voltage needs to be boosted, a boost circuit 102 may be provided. The control end of the boost circuit 120 is connected to the controller 301, the output end of the boost circuit 102 is connected to the battery pack, and the input end of the boost circuit 102 is connected to the power supply VCC through an input port.

[0081] The boost circuit 102 is a circuit for boosting an input voltage. The boost circuit 102 mainly boosts the power supply voltage input by the power supply VCC through the synergistic effect of the energy storage structure and the switch structure.

[0082] The boost circuit 102 is used to boost the current charging voltage to obtain a boosted charging voltage according to the adjusted PWM driving signal output by the controller 301 during the boost power supply process, and output the boosted charging voltage to the battery pack.

[0083] In consideration of the charging voltage fluctuation, the buck circuit 101 and the boost circuit 102 can be set at the same time. In the specific working process, if the current charging power is greater than the target charging power required by the load, the controller 301 can reduce the voltage value of the charging voltage output by the buck circuit 101 by reducing the duty cycle of the PWM drive signal input to the buck circuit 101, and in the case where the voltage value of the charging voltage is reduced, since the internal resistance of the connected battery pack has not changed, the current value of the charging current will also be reduced, thereby matching the reduced output power with the target charging power. If the current charging power is less than the target charging power required by the load, the controller 301 can increase the duty cycle of the PWM drive signal input to the boost circuit 102, so that the voltage value of the charging voltage output by the boost circuit 102 increases, and in the case where the voltage value of the charging voltage increases, since the internal resistance of the connected battery pack has not changed, the current value of the charging current will also increase, thereby matching the increased output power with the target charging power.

[0084] Reference Figure 4 , Figure 4 This is a third structural diagram of the second embodiment of the battery pack charging circuit of the present application. When a transformer is used for voltage conversion, the voltage conversion circuit 10 includes a switch tube Q and a transformer T drawn by PCB copper foil;

[0085] The first end of the switch tube Q is connected to the controller 301, the second end of the switch tube Q is connected to the primary coil of the transformer T, and the third end of the switch tube Q is connected to the power supply VCC or ground; the secondary coil of the transformer T is connected to the battery pack.

[0086] It is understandable that in this embodiment, voltage changes can also be achieved through the transformer T structure, and a connection is established between the switch tube Q and the primary coil of the transformer T to control the conduction time of the primary coil, thereby controlling the voltage value of the output charging voltage of the secondary coil of the transformer T. Of course, the voltage value of the output charging voltage of the secondary coil can also be controlled by controlling the number of turns of the primary coil. For example, when the target charging power is greater than the current charging power, the number of turns of the primary coil can be increased to increase the voltage value of the output charging voltage of the secondary coil. The transformer T drawn with PCB copper foil can effectively reduce the cost of the transformer due to the particularity of its material.

[0087] It should be noted that the switch tube Q has an on-off function for controlling the conduction and cutoff between the primary coil of the transformer T and the power supply VCC. The switch tube Q can be a triode, a MOS tube, an IGBT, etc. The switch tube Q is arranged in series in the branch where the primary coil is located. The first end of the switch tube Q is the control end, which is connected to the controller 301 and is used to receive the PWM drive signal; the second end of the switch tube Q can be one of the input end or the output end, and the third end is the other; when the input end is connected to the power supply VCC, the output end is connected to the input end of the primary coil, and the output end of the primary coil is grounded; when the input end of the primary coil is directly connected to the power supply VCC, the output end of the primary coil is connected to the input end of the switch tube Q, and the output end of the switch tube Q is grounded.

[0088] In a specific implementation, the controller 301 can output the PWM drive signal after adjusting the duty cycle to the control end of the switch tube Q, and the switch tube Q controls the conduction time of the branch where the primary coil is located according to the PWM drive signal, thereby adjusting the charging voltage output by the secondary coil of the transformer Q. For example, when the target charging power required by the battery pack is greater than the current charging power, the controller 301 can increase the duty cycle of the PWM drive signal, and then output the adjusted PWM drive signal to the switch tube Q, increase the conduction time of the switch tube Q, and then increase the working time of the primary coil, so that the secondary coil of the transformer Q outputs a charging voltage with an increased voltage value.

[0089] Reference Figure 5 , Figure 5 The third embodiment of the battery pack charging circuit of the present application is proposed based on the first embodiment or the second embodiment.

[0090] In this embodiment, the battery pack charging circuit is further provided with a UDS diagnostic circuit 50 .

[0091] It is understandable that during the charging process of the battery pack, anomalies may occur, such as short circuits and short circuits in the charging circuit, which may damage the battery pack charging circuit and the battery pack. In order to avoid damage, the charging process can be diagnosed by setting a UDS diagnostic circuit 50.

[0092] Among them, the UDS diagnostic circuit 50 is connected to the controller 301, and is used to receive the current charging current and the current charging voltage output by the controller, and when the current charging voltage is greater than the preset voltage and / or the current charging current is greater than the preset current, feedback a fault signal to the controller 301; the controller 301 is used to stop outputting the PWM drive signal to the voltage conversion circuit 10 when receiving the fault signal.

[0093] It should be noted that the UDS diagnostic circuit 50 is mainly used to diagnose abnormalities during the charging process. The UDS diagnostic circuit 50 can be composed of a diagnostic chip and related peripheral structures, or it can be composed of structures such as a comparator and an amplifier. When the controller 301 receives parameters such as the current charging current and the current charging voltage, the controller 301 can send these parameters to the UDS diagnostic circuit 50, and the UDS diagnostic circuit 50 will diagnose and feedback whether there is an abnormality in the current charging process. The preset current is a current preset to determine whether there is an overcurrent abnormality in the current charging process. The preset voltage is a voltage preset to determine whether there is an overvoltage abnormality in the current charging process.

[0094] In a specific implementation, the UDS diagnostic circuit 50 can compare the current charging current with the preset current, and compare the current charging voltage with the preset voltage; when the current charging current is less than the preset current and the current charging voltage is less than the preset voltage, it can be determined that there is no overcurrent or overvoltage abnormality in the current charging process. However, when any of the current charging current is greater than the preset current and the current charging voltage is greater than the preset voltage, it can be determined that there is overcurrent and / or overvoltage in the current charging process. At this time, the UDS diagnostic circuit 50 can feed back an abnormal signal to the controller 301, and the controller 301 can stop outputting the PWM drive signal to the voltage conversion circuit 10 when receiving the abnormal signal, so as to stop the current charging process.

[0095] In addition, the controller 301 can also receive relevant parameters in the battery pack, and then transmit the parameters to the UDS diagnostic circuit 50. The UDS diagnostic circuit 50 can also diagnose whether an abnormality occurs in the battery pack. When an abnormality is confirmed in the battery pack, an abnormal instruction can also be fed back to the controller 301 to stop the charging process.

[0096] It should be understood that the battery pack will continuously generate heat during the charging process, and the temperature of the battery pack may be too high during the charging process.

[0097] In view of the possibility of overheating of the battery pack, in this embodiment, the controller 301 is also connected to the battery pack via a CAN bus. A temperature detection component may be provided inside the battery pack, and the temperature information inside the battery pack is detected by the temperature detection component. The detected temperature information can be transmitted to the controller 301 via the CAN bus. The controller 301 can determine whether the battery pack is overheated based on the received temperature information.

[0098] In a specific implementation, the controller 301 can receive the battery temperature value outputted from the battery pack, and when the battery temperature value is greater than a preset temperature value, stop outputting the PWM drive signal to the voltage conversion circuit 10. The preset temperature value is a temperature value pre-set to determine whether the battery pack is overheated. When the battery temperature value reaches the preset temperature value, it is determined that the battery pack is in an overheated state, and when it is determined that the battery pack is overheated, the controller 301 stops outputting the PWM drive signal, thereby controlling the charging process to stop until the battery pack temperature returns to normal.

[0099] Furthermore, when the voltage conversion circuit 10 outputs a charging voltage, the charging voltage may be affected by interference, resulting in a certain degree of change in the charging voltage and the charging current. This partial change will also have a certain impact on the battery pack. Therefore, in this embodiment, the battery pack charging circuit is further provided with a voltage stabilizing circuit 60;

[0100] The input end of the voltage stabilizing circuit 60 is connected to the output end of the voltage conversion circuit 10 , and the output end of the voltage stabilizing circuit 60 is connected to the feedback circuit 20 and the battery pack.

[0101] It is understandable that the voltage stabilizing circuit 60 is a circuit for stabilizing the charging voltage amplitude. The voltage stabilizing circuit 60 can be a voltage stabilizing circuit of an energy storage structure, such as an energy storage capacitor to prevent sudden changes in voltage values; it can also be a voltage stabilizing circuit of a filtering structure, which filters out the interference noise when there is noise interference in the charging voltage, such as a filter.

[0102] In a specific implementation, the voltage conversion circuit 10 can send the converted charging voltage to the temperature and circuit 60, and the voltage stabilization circuit 60 can stabilize the charging voltage and output the stabilized charging voltage to the battery pack to charge the battery pack.

[0103] In addition, during the collection process of the feedback circuit 20, in order to avoid interference, the input end of the feedback circuit 20 can also be connected to the output end of the voltage stabilization circuit 60, so that the current charging voltage and the current charging current after voltage stabilization can be adjusted more accurately.

[0104] Reference Figure 6 , Figure 6 The fourth embodiment of the battery pack charging circuit of the present application is proposed based on any one of the first to third embodiments described above.

[0105] It is understandable that the feedback circuit 20 needs to detect the charging voltage and charging current output to the battery pack, and voltage detection is different from current detection. Usually, voltage detection is mainly performed by parallel resistors, while current detection is mainly performed by series resistors. Therefore, in this embodiment, in order to detect the current charging voltage and the current charging current at the same time, the feedback circuit 20 can be configured to include: a voltage feedback circuit 201 and a current feedback circuit 202;

[0106] It should be noted that the voltage feedback circuit 201 is a circuit for detecting and feeding back the current charging voltage input to the battery pack, and the current detection circuit 202 is a circuit for detecting and feeding back the current charging current input to the battery pack.

[0107] The voltage feedback circuit 201 and the current feedback circuit 202 are also connected to the charging control circuit 30 to feed back the collected current charging voltage and current to the logic operation chip 302 in the charging control circuit 30. The current charging power is determined by the logic operation chip 302 and output to the controller 301.

[0108] During the battery pack charging process, the voltage feedback circuit 201 can detect the current charging voltage output to the battery pack, and the current feedback circuit 202 can detect the current charging current output to the battery pack; then the detected current charging voltage and current charging current are output to the charging control circuit 30 respectively.

[0109] In addition, when the voltage feedback circuit 201 and the current feedback circuit 202 are respectively provided, in order to avoid the current charging current or the current charging voltage collected being too small, which makes it difficult to accurately control the voltage conversion circuit 10, in this embodiment, the battery pack charging circuit may further be provided with: a voltage amplifier circuit 701 and a current amplifier circuit 702;

[0110] The voltage amplifier circuit 701 is connected to the voltage feedback circuit 201 , the current amplifier circuit 702 is connected to the current feedback circuit 202 , and the logic operation chip 302 in the charging control circuit 30 is connected to the voltage amplifier circuit 701 and the current amplifier circuit 702 , respectively.

[0111] Considering that the current charging voltage detected by the voltage feedback circuit 201 may be small, and the logic operation chip 302 in the charging control circuit 30 cannot accurately identify it, the voltage amplifier circuit 701 can convert the voltage signal of the weak current charging voltage into a voltage signal that is easy to collect. For example, the voltage value of the current charging voltage detected is 0.3V, and the amplified voltage value is 5V, which is easier to be identified by the logic operation chip 302 in the charging control circuit 30. Similarly, the current amplifier circuit 702 can amplify the current charging current with a small current value, which can be more easily identified by the logic operation chip 302 in the charging control circuit 30.

[0112] In a specific implementation, the voltage amplifier circuit 701 can amplify the current charging voltage output by the voltage feedback circuit 201; amplify the current charging current output by the current feedback circuit; and the logic operation chip 302 in the charging control circuit 30 can determine the current charging power based on the amplified current charging voltage and the amplified current charging current.

[0113] Reference Figure 7 In this embodiment, the voltage amplifying circuit 701 includes: a first amplifier A1, a first resistor R1, a second resistor R2, a third resistor R3, a first capacitor C1 and a second capacitor C2;

[0114] A first end of the first resistor R1 is connected to the voltage feedback circuit 201 and a first end of the first capacitor C1, a second end of the first resistor R1 is connected to the positive input end of the first amplifier A1 and a first end of the second capacitor C2; a first end of the second resistor R2 is connected to a first end of the third resistor R3 and a negative input end of the first amplifier A1, a second end of the third resistor R3 is connected to an output end of the first amplifier A1; a second end of the second resistor R2, a second end of the first capacitor C1 and a second end of the second capacitor C2 are grounded GND.

[0115] It should be understood that in this embodiment, an amplifier is used to amplify the current charging voltage, wherein the first operational amplifier A1, the second resistor R2 and the third resistor R3 form a unidirectional amplifier; the first resistor R1, the first capacitor C1 and the second capacitor C2 form a filter circuit for filtering out interference in the current charging voltage.

[0116] In a specific implementation, after the current charging voltage is filtered out by a filter circuit composed of a first resistor R1, a first capacitor C1 and a second capacitor C2, it is amplified by a common-direction amplifier composed of an operational amplifier A1, a second resistor R2 and a third resistor R3 to obtain the amplified current charging voltage, which can then be accurately identified by the logic operation chip 302 in the charging control circuit 30.

[0117] The current amplifying circuit 702 includes: a second amplifier A2, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a third capacitor C3 and a fourth capacitor C4;

[0118] A first end of the fourth resistor R4 is connected to the current feedback circuit 202 and a first end of the third capacitor C3, and a second end of the fourth resistor R4 is connected to the positive input end of the second amplifier A2 and a first end of the fourth capacitor C4; a first end of the fifth resistor R5 is connected to a first end of the sixth resistor R6 and a negative input end of the second amplifier A2, and a second end of the sixth resistor R6 is connected to an output end of the second amplifier A2; a second end of the fifth resistor R5, a second end of the third capacitor C3, and a second end of the fourth capacitor C4 are grounded GND.

[0119] It should be understood that in this embodiment, an amplifier is used to amplify the current charging current, wherein the second operational amplifier A2, the fifth resistor R5 and the sixth resistor R6 form a unidirectional amplifier; the fourth resistor R4, the third capacitor C3 and the fourth capacitor C4 form a filter circuit for filtering out interference in the current charging current.

[0120] In a specific implementation, after the current charging current is filtered out by a filter circuit composed of a fourth resistor R4, a third capacitor C3 and a fourth capacitor C4, it is amplified by a second operational amplifier A2, a fifth resistor R5 and a sixth resistor R6 to form a unidirectional amplifier, and the amplified current charging current can be obtained, which can then be accurately identified by the logic operation chip 302 in the charging control circuit 30.

[0121] Reference Figure 8 , Figure 8 This is a schematic diagram of the circuit principle structure of the battery pack charging circuit of this application. Figure 8In the embodiment, the controller 301 can output a PWM drive signal to control the voltage conversion circuit 10 to charge the battery pack through the voltage stabilizing circuit 60 and the output port. During the battery pack charging process, the power request circuit 40 can determine the target charging power required by the battery pack through the remaining power in the battery pack, and then transmit the target charging power to the controller 301 through the CAN bus; at the same time, the voltage feedback circuit 201 can detect the current charging voltage output to the battery pack, and output it to the logic control chip 302 after amplification through the voltage amplifier circuit 701, and the current feedback circuit 202 can detect the current charging current output to the battery pack, and output it to the logic control chip 302 after amplification through the current amplifier circuit 702; the logic control chip 302 can determine the current charging power according to the current charging voltage and the current charging current, and output the current charging power to the controller 301. The controller 301 can adjust the duty cycle of the PWM drive signal input to the voltage conversion circuit 10 according to the current charging power and the target charging power, thereby adjusting the charging voltage of the battery pack, and can adjust the charging voltage when the current charging voltage or charging current fluctuates to avoid damage to the battery pack.

[0122] Based on the above embodiments, the present application also proposes a battery pack charging system, comprising an input port, an output port and the battery pack charging circuit, wherein the battery pack charging circuit is connected to the power supply through the input port, and the battery pack charging circuit is connected to the battery pack through the output port.

[0123] It should be noted that, in this article, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or system. In the absence of further restrictions, an element defined by the sentence "comprises a ..." does not exclude the existence of other identical elements in the process, method, article or system including the element.

[0124] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.

[0125] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as a read-only memory / random access memory, a disk, or an optical disk), and includes several events to enable a terminal device (which can be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to execute the methods described in each embodiment of the present application.

[0126] The above are only preferred embodiments of the present application, and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A battery pack charging circuit, characterized in that: include: Voltage conversion circuit, feedback circuit and charging control circuit; The charging control circuit is connected to the battery pack and is used to obtain the target charging power required by the battery pack; The feedback circuit is connected to the output end of the voltage conversion circuit and is used to detect the current charging voltage and current input to the battery pack; The charging control circuit is also connected to the feedback circuit, and is used to determine the current charging power according to the current charging voltage and the current charging current output by the feedback circuit, and to adjust the PWM driving signal output to the voltage conversion circuit according to the target charging power and the current charging power; The voltage conversion circuit is connected to the charging control circuit and the battery pack, and is used to adjust the charging voltage output to the battery pack according to the adjusted PWM drive signal.

2. The battery pack charging circuit according to claim 1, characterized in that: The charging control circuit includes a controller and a logic operation chip; The logic operation chip is connected to the feedback circuit, and is used to determine the current charging power according to the current charging voltage and the current charging current; The controller is connected to the logic operation chip, the battery pack and the voltage conversion circuit, and is used to adjust the PWM drive signal output to the voltage conversion circuit according to the target charging power and the current charging power.

3. The battery pack charging circuit according to claim 2, characterized in that: The voltage conversion circuit includes: a buck circuit and / or a boost circuit; The control end of the buck circuit is connected to the controller, the output end of the buck circuit is connected to the battery pack, and the input end of the buck circuit is connected to the power supply through an input port; The buck circuit is used to step down the current charging voltage to obtain a step-down charging voltage according to the PWM driving signal adjusted by the controller during the step-down power supply process, and output the step-down charging voltage to the battery pack; The control end of the boost circuit is connected to the controller, the output end of the boost circuit is connected to the battery pack, and the input end of the boost circuit is connected to the power supply through an input port; The boost circuit is used to boost the current charging voltage to obtain a boosted charging voltage according to the adjusted PWM driving signal output by the controller during the boost power supply process, and output the boosted charging voltage to the battery pack.

4. The battery pack charging circuit according to claim 2, characterized in that: The voltage conversion circuit includes a switch tube and a transformer drawn with PCB copper foil; The first end of the switch tube is connected to the controller, the second end of the switch tube is connected to the primary coil of the transformer, and the third end of the switch tube is connected to the power supply or ground; the secondary coil of the transformer is connected to the battery pack.

5. The battery pack charging circuit as claimed in claim 2, characterized in that: The battery pack charging circuit also includes: a power request circuit; The power request circuit is connected to the battery pack and connected to the controller via a CAN bus; The power request circuit is used to obtain the current remaining power of the battery pack during the charging process of the battery pack, and determine the target charging power required by the battery pack according to the current remaining power.

6. The battery pack charging circuit as claimed in claim 2, characterized in that: The battery pack charging circuit also includes: a UDS diagnostic circuit; The UDS diagnostic circuit is connected to the controller, and is used to receive the current charging current and the current charging voltage output by the controller, and when the current charging voltage is greater than a preset voltage and / or the current charging current is greater than a preset current, feed back a fault signal to the controller; The controller is further configured to stop outputting the PWM drive signal to the voltage conversion circuit when receiving the fault signal.

7. The battery pack charging circuit as claimed in claim 2, characterized in that: The controller is also connected to the battery pack via a CAN bus, for receiving a battery temperature value output from the battery pack, and when the battery temperature value is greater than a preset temperature value, stops outputting the PWM drive signal to the voltage conversion circuit.

8. The battery pack charging circuit according to claim 1, characterized in that: The battery pack charging circuit also includes: a voltage stabilizing circuit; The input end of the voltage stabilizing circuit is connected to the output end of the voltage conversion circuit, and the output end of the voltage stabilizing circuit is connected to the feedback circuit and the battery pack; The voltage stabilizing circuit is used to stabilize the charging voltage output by the voltage conversion circuit, and output the stabilized charging voltage to the battery pack.

9. The battery pack charging circuit according to any one of claims 1 to 8, characterized in that: The feedback circuit includes: a voltage feedback circuit and a current feedback circuit; The voltage feedback circuit is connected to the output end of the voltage conversion circuit and is used to detect the current charging voltage input to the battery pack; The current feedback circuit is connected to the output end of the voltage conversion circuit and is used to detect the current charging current input to the battery pack.

10. The battery pack charging circuit according to claim 9, characterized in that: The battery pack charging circuit also includes: a voltage amplification circuit and a current amplification circuit; The voltage amplifying circuit is connected to the voltage feedback circuit and is used to amplify the current charging voltage output by the voltage feedback circuit; The current amplifying circuit is connected to the current feedback circuit and is used to amplify the current charging current output by the current feedback circuit; The charging control circuit is connected to the voltage amplifying circuit and the current amplifying circuit respectively, and is used to determine the current charging power according to the amplified current charging voltage and the amplified current charging current.

11. The battery pack charging circuit according to claim 10, characterized in that: The voltage amplification circuit comprises: a first amplifier, a first resistor, a second resistor, a third resistor, a first capacitor and a second capacitor; The first end of the first resistor is connected to the voltage feedback circuit and the first end of the first capacitor, the second end of the first resistor is connected to the positive input end of the first amplifier and the first end of the second capacitor; the first end of the second resistor is connected to the first end of the third resistor and the negative input end of the first amplifier, the second end of the third resistor is connected to the output end of the first amplifier; the second end of the second resistor, the second end of the first capacitor and the second end of the second capacitor are grounded; The current amplifying circuit comprises: a second amplifier, a fourth resistor, a fifth resistor, a sixth resistor, a third capacitor and a fourth capacitor; A first end of the fourth resistor is connected to the current feedback circuit and a first end of the third capacitor, and a second end of the fourth resistor is connected to a positive input end of the second amplifier and a first end of the fourth capacitor; a first end of the fifth resistor is connected to a first end of the sixth resistor and a negative input end of the second amplifier, and a second end of the sixth resistor is connected to an output end of the second amplifier; a second end of the fifth resistor, a second end of the third capacitor, and a second end of the fourth capacitor are grounded.

12. A battery pack charging system, characterized in that: It comprises an input port, an output port and a battery pack charging circuit as claimed in any one of claims 1 to 11, wherein the battery pack charging circuit is connected to a power supply via the input port, and the battery pack charging circuit is connected to a battery pack via the output port.

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