A multi-battery management circuit for a vehicle refrigerator and a control method thereof

Abstract

The application provides a multi-battery management circuit for a vehicle-mounted refrigerator and a control method thereof, and the technical scheme is as follows: the multi-battery management circuit comprises a battery input module, a detection circuit module, a relay driving circuit, a relay module and a battery output module, and further comprises an auxiliary power on-off circuit for controlling the power on-off of the whole circuit system, the auxiliary power on-off circuit is electrically connected with the battery input module, the auxiliary power on-off circuit is electrically connected with an auxiliary power down-conversion circuit, and the output end of the auxiliary power down-conversion circuit is electrically connected with the relay driving circuit and the relay module; the application is electrically connected between the battery and the main control board of the vehicle-mounted refrigerator, can effectively cut off the electrical connection between the battery seats of the vehicle-mounted refrigerator, prevents the battery seat without the installed battery from being electrified, thereby effectively preventing electric shock when the battery is installed or replaced, and solves the defects and safety hazards existing in the power supply structure of the existing vehicle-mounted refrigerator.

Description

[Technical Field]

[0001] This invention relates to the field of power control for vehicle refrigerators, and particularly to a multi-battery management circuit and its control method for vehicle refrigerators. [Background Technology]

[0002] In existing vehicle refrigerator structures, most use multiple batteries connected in parallel for power. However, in these power structures, the battery voltage is directly output to the main control board. The complex circuitry within the main control board can cause interconnections between battery holders, energizing even battery holders that are not yet inserted. Since the electrode plates of the battery holders are exposed inside the battery compartment, accidental contact is possible during battery installation or replacement. Furthermore, many vehicle refrigerators use 36V batteries, and accidental contact with energized electrode plates can cause harm to the human body. Therefore, the existing power structure of vehicle refrigerators has certain defects and safety hazards. [Summary of the Invention]

[0003] To address the shortcomings of existing power supply structures in vehicle refrigerators and to isolate battery holders from each other to prevent electric shock during battery installation or replacement, this invention provides a multi-battery management circuit and its control method for vehicle refrigerators.

[0004] This invention is achieved through the following technical solution:

[0005] A multi-battery management circuit for a vehicle refrigerator is characterized by comprising a battery input module electrically connected to the electrodes of a battery holder in the vehicle refrigerator, the battery input module being electrically connected to a detection circuit module for detecting whether a battery is installed and connected, the detection circuit module being electrically connected to a relay drive circuit, the relay drive circuit being electrically connected to a relay module, the relay module being electrically connected to a battery output module electrically connected to the main control board of the vehicle refrigerator, and the multi-battery management circuit further comprising an auxiliary power on / off circuit for controlling the power supply of the entire circuit system, the auxiliary power on / off circuit being electrically connected to the battery input module, the auxiliary power on / off circuit being electrically connected to an auxiliary power step-down circuit for converting the battery voltage to the voltage required by the multi-battery management circuit, and the output terminal of the auxiliary power step-down circuit being electrically connected to the relay drive circuit and the relay module respectively.

[0006] The multi-battery management circuit for a vehicle refrigerator as described above is characterized in that: the vehicle refrigerator has multiple batteries connected in parallel, each battery in the battery input module has a battery input port, and each battery input port in the battery output module has an output port.

[0007] The multi-battery management circuit for a vehicle refrigerator as described above is characterized in that: a detection circuit is provided for each battery access port in the detection circuit module, a first optocoupler for transmitting detection signals is provided in the detection circuit, the light-emitting diode pin of the first optocoupler is electrically connected to the battery access port, and the output pin of the first optocoupler is electrically connected to the relay drive circuit.

[0008] The multi-battery management circuit for a vehicle refrigerator described above is characterized in that: the detection circuit is further provided with a second optocoupler for controlling the on / off state of the light-emitting diode in the first optocoupler and reducing energy consumption, the pin of the light-emitting diode in the second optocoupler is electrically connected to the output terminal of the auxiliary power supply step-down circuit, and the output pin of the second optocoupler is connected to the circuit of the pin of the light-emitting diode in the first optocoupler.

[0009] The multi-battery management circuit for a vehicle refrigerator as described above is characterized in that: the relay driving circuit includes a driving chip U3, pins 1 to 8 of the driving chip U3 are signal input I / O ports, which are electrically connected to the corresponding detection circuits respectively; pins 1 to 8 of the driving chip U3 are connected in series with diodes and resistors and then electrically connected to the output terminal of the auxiliary power supply step-down circuit; the connection point between the detection circuit and the relay driving circuit is located between the positive terminal of the diode and the resistor; pin 9 of the driving chip U3 is grounded; pin 10 is electrically connected to the output terminal of the auxiliary power supply step-down circuit; pins 11 to 18 of the driving chip U3 are signal output I / O ports, which are electrically connected to the corresponding relay pins in the relay module respectively.

[0010] The multi-battery management circuit for a vehicle refrigerator described above is characterized in that: two relays are provided in the relay module for each of the battery access ports, and the relays in the relay module are normally closed single-pole double-throw relays.

[0011] The multi-battery management circuit for a vehicle refrigerator as described above is characterized in that: a relay is provided for each battery access port in the relay module, and the relay in the relay module is a normally closed double-pole double-throw relay.

[0012] The multi-battery management circuit for a vehicle refrigerator as described above is characterized in that: a magnet is provided on the cover of the vehicle refrigerator battery box, and a magnetic control switch is provided inside the battery box corresponding to the magnet. The magnetic control switch is normally closed, and the magnetic control switch is electrically connected to the auxiliary power supply on / off circuit through port CN2 or port CN10.

[0013] The multi-battery management circuit for a vehicle refrigerator as described above is characterized in that: the auxiliary power supply switching circuit includes a MOSFET Q1; the auxiliary power supply switching circuit has multiple parallel input terminals, each electrically connected to a corresponding output port pin; the multiple parallel input terminals of the auxiliary power supply switching circuit are connected in series with diodes and then electrically connected to the source S of the MOSFET Q1; the gate G of the MOSFET Q1 is connected in series with resistor R14 and diode D15 and then electrically connected to pin 1 of the signal input port CN2 or port CN10 of the magnetic switch; a resistor R2, a Zener diode D10, and a capacitor C4 are connected in parallel between the source S and the gate G of the MOSFET Q1; the anode of the Zener diode D10 is electrically connected to the gate G of the MOSFET Q1, and the cathode is electrically connected to the source S of the MOSFET Q1; the drain D of the MOSFET Q1 is the output terminal of the auxiliary power supply switching circuit and is connected to the auxiliary power supply switching circuit. The auxiliary power supply step-down circuit is electrically connected, including a step-down chip U4. Pin 1 of the step-down chip U4 is connected in series with resistor R15 and then electrically connected to the drain D of MOSFET Q1. Capacitor C2 is connected in parallel with polarized capacitor C5. One end of capacitor C2 is electrically connected to the positive terminal of polarized capacitor C5 between pin 1 of step-down chip U4 and resistor R15. The other end of capacitor C2 is grounded to the negative terminal of polarized capacitor C5. Pins 4 to 8 of step-down chip U4 are all grounded. Pin 3 of step-down chip U4 is electrically connected to the positive terminal of polarized capacitor C1. The negative terminal of polarized capacitor C1 is grounded. Pin 2 of step-down chip U4 is electrically connected to the negative terminal of rectifier diode D1 and one end of inductor L1, respectively. The positive terminal of rectifier diode D1 is grounded. The other end of inductor L1 is electrically connected to the positive terminal of polarized capacitor C1. The connection point between inductor L1 and the positive terminal of polarized capacitor C1 is the output terminal of the auxiliary power supply step-down circuit.

[0014] A control method employing the aforementioned multi-battery management circuit is characterized in that: the multi-battery management circuit can add or remove corresponding electronic devices according to the number of batteries in the vehicle refrigerator. Taking a vehicle refrigerator with four batteries as an example, the operation process of the multi-battery management circuit is as follows:

[0015] When the battery compartment cover of the vehicle refrigerator is closed, the magnet is close to the magnetic switch, and the normally closed magnetic switch is open. The MOS transistor Q1 in the auxiliary power supply circuit is de-energized, and the multi-battery management circuit does not work. Since the relay in the relay module is normally closed, the battery power is normally transmitted from the battery input module to the battery output module, and the vehicle refrigerator works normally.

[0016] When installing or removing / replacing a battery, the cover of the vehicle refrigerator battery compartment opens, the magnet moves away from the magnetic control switch, and the normally closed magnetic control switch returns to the closed state. When a battery is inserted into the battery holder and the battery compartment is not empty, the MOS transistor Q1 in the auxiliary power supply switching circuit is energized, and the multi-battery management circuit starts to operate. The auxiliary power supply step-down circuit reduces the battery voltage output to provide suitable voltage for the relay drive circuit, the detection circuit module, and the relay module, enabling them to work normally.

[0017] When a battery holder with a battery inserted is in operation, the detection circuit corresponding to the battery holder is turned on. The second optocoupler in the detection circuit is activated, the loop of the first optocoupler is turned on, and the first optocoupler connected to the battery voltage starts to work, pulling the level of the corresponding input I / O port in the relay drive circuit low. The corresponding output I / O port in the relay drive circuit outputs a high-level voltage to the corresponding relay pin. Since the other pin of the corresponding relay is also in a high-level state, the corresponding relay does not switch and remains in a normally closed state. The battery access port and the output port corresponding to the battery holder are normally connected.

[0018] When a battery holder without a battery is inserted, the corresponding detection circuit is not active. The second optocoupler in the detection circuit is active, and the first optocoupler is not active because it cannot connect to the battery voltage. The corresponding input I / O port of the relay drive circuit continuously inputs a high-level voltage signal, and the corresponding output I / O port of the relay drive circuit outputs a low-level voltage to the corresponding relay pin. Since the other pin of the corresponding relay is in a high-level state, the corresponding relay is active, switching the relay switch to the off state, thus disconnecting the battery input port and the output port corresponding to the battery holder. This ensures that the battery holder without a battery is not energized, meeting the safety requirement of being harmless to human touch.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1. The present invention provides a multi-battery management circuit for vehicle refrigerators, which is electrically connected between the battery and the main control board of the vehicle refrigerator. It can effectively isolate the electrical connection between the battery holders of the vehicle refrigerator, without affecting the power transmission of the battery holder with the battery installed. At the same time, it can prevent the battery holder without the battery installed from being energized, thereby effectively preventing electric shock when installing or removing and replacing the battery. It solves the defects and safety hazards existing in the power supply structure of the existing vehicle refrigerators.

[0021] 2. This invention relates to a multi-battery management circuit for a vehicle refrigerator. A magnet is installed on the battery compartment cover of the vehicle refrigerator, and a normally closed magnetic switch is installed inside the battery compartment corresponding to the magnet. All relays in the relay module are normally closed. When the vehicle refrigerator is in normal use, the battery compartment cover is closed, the magnet approaches the magnetic switch, and the normally closed magnetic switch is open, de-energizing the auxiliary power supply circuit. The multi-battery management circuit does not operate. Because the relays in the relay module are normally closed, battery power is transmitted normally, and the vehicle refrigerator operates normally. This ensures that the multi-battery management circuit does not increase battery power consumption during normal vehicle refrigerator use. Furthermore, a second optocoupler is installed in the detection circuit. The first optocoupler operates with the battery voltage. Without the second optocoupler, when there is a battery in the battery compartment and the cover is closed, the first optocoupler will continuously operate, increasing battery power consumption. When the battery compartment cover is closed and the vehicle refrigerator is in normal use, the second optocoupler can disconnect the working circuit of the first optocoupler, eliminating the first optocoupler's power consumption on the battery.

[0022] 3. The control method of the multi-battery management circuit adopted in this invention is simple to operate and does not require complex calculations. It can add or remove corresponding electronic devices according to the number of batteries in the vehicle refrigerator and is applicable to all multi-battery vehicle refrigerator models. [Attached Image Description]

[0023] Figure 1 This is a block diagram of the multi-battery management circuit;

[0024] Figure 2 This is the overall circuit schematic of the multi-battery management circuit;

[0025] Figure 3 This is the circuit diagram of the auxiliary power supply switching circuit;

[0026] Figure 4 This is the circuit diagram of the auxiliary power supply step-down circuit;

[0027] Figure 5 This is a circuit diagram of the battery input port, detection circuit, and output port;

[0028] Figure 6 This is the circuit diagram of a relay drive circuit;

[0029] Figure 7 This is a circuit diagram of a single-pole double-throw relay embodiment in the relay module;

[0030] Figure 8 This is a circuit diagram of an embodiment of a double-pole double-throw relay in a relay module.

[0031] In the diagram: 1 is the battery input module; 2 is the detection circuit module; 3 is the relay drive circuit; 4 is the relay module; 5 is the battery output module; 6 is the auxiliary power supply switching circuit; 7 is the auxiliary power supply step-down circuit; 8 is the battery input port; 9 is the output port; 10 is the detection circuit; 11 is the first optocoupler; 12 is the second optocoupler; 13 is the single-pole double-throw relay; 14 is the double-pole double-throw relay; 15 is the magnet; 16 is the magnetic switch.

Detailed Implementation Methods

[0032] The technical features of the present invention will be further described in detail below with reference to the accompanying drawings so that those skilled in the art can understand them.

[0033] This multi-battery management circuit can add or remove corresponding electronic devices according to the number of batteries in the vehicle refrigerator. Taking a vehicle refrigerator with four batteries and a normally closed single-pole double-throw relay as an example, the connection relationship of this multi-battery management circuit will be described in detail.

[0034] A multi-battery management circuit for vehicle refrigerators, such as Figures 1 to 8 As shown, the system includes a battery input module 1 electrically connected to the electrodes of the battery holder in the vehicle refrigerator. The battery input module 1 is electrically connected to a detection circuit module 2 for detecting whether a battery is installed and connected. The detection circuit module 2 is electrically connected to a relay drive circuit 3. The relay drive circuit 3 is electrically connected to a relay module 4. The relay module 4 is electrically connected to a battery output module 5 electrically connected to the main control board of the vehicle refrigerator. The multi-battery management circuit also includes an auxiliary power on / off circuit 6 for controlling the power supply to the entire circuit system. The auxiliary power on / off circuit 6 is electrically connected to the battery input module 1. The power supply circuit 6 is electrically connected to an auxiliary power step-down circuit 7 for converting the battery voltage to the voltage required by the multi-battery management circuit. The output terminal of the auxiliary power step-down circuit 7 is electrically connected to the relay drive circuit 3 and the relay module 4, respectively. The multi-battery management circuit is electrically connected between the battery and the main control board of the vehicle refrigerator. It can effectively isolate the electrical connection between the battery holders of the vehicle refrigerator, without affecting the power transmission of the battery holder with the battery installed. At the same time, it can prevent the battery holder without the battery installed from being charged, thereby effectively preventing electric shock when installing or removing and replacing the battery, and solving the defects and safety hazards existing in the power supply structure of the existing vehicle refrigerator.

[0035] Specifically, the vehicle refrigerator contains four batteries connected in parallel. Each battery in the battery input module 1 has a corresponding battery input port 8, and each battery output module 5 has a corresponding output port 9. The first battery input port CN1 has pin 3 electrically connected to the positive terminal VB1 of battery 1 and pin 3 of relay RELAY1; pin 1 of CN1 is electrically connected to the negative terminal GND1 of battery 1 and pin 3 of relay RELAY2. The second battery input port CN3 has pin 3 electrically connected to the positive terminal VB2 of battery 2 and pin 3 of relay RELAY3; pin 1 of CN3 is electrically connected to the negative terminal GND2 of battery 2 and pin 3 of relay RELAY4. The third battery input port CN4 has pin 3 electrically connected to the battery input port CN4. The positive terminal VB3 of battery 3 is electrically connected to pin 3 of relay RELAY5. Pin 1 of CN4 is electrically connected to the negative terminal GND3 of battery 3 and pin 3 of relay RELAY6. Pin 3 of the fourth battery input port CN5 is electrically connected to the positive terminal VB4 of battery 4 and pin 3 of relay RELAY7. Pin 1 of CN5 is electrically connected to the negative terminal GND4 of battery 4 and pin 3 of relay RELAY8. Pin 1 of the first output port CN6 is electrically connected to pin 5 of relay RELAY1. Pin 1 of the second output port CN7 is electrically connected to pin 5 of relay RELAY3. Pin 1 of the third output port CN8 is electrically connected to pin 5 of relay RELAY5. Pin 1 of the fourth output port CN9 is electrically connected to pin 5 of relay RELAY7.

[0036] Specifically, in the detection circuit module 2, a detection circuit 10 is provided for each of the battery access ports 8. The detection circuit 10 is provided with a first optocoupler 11 for transmitting detection signals and a second optocoupler 12 for controlling the on / off state of the light-emitting diode in the first optocoupler 11 and reducing energy consumption. The first optocoupler 11 operates by connecting to the battery voltage. If the second optocoupler 12 is not present, the first optocoupler 11 will continue to operate when there is a battery in the battery box and the box cover is closed, increasing the energy consumption of the battery. When the battery box cover is closed and the car refrigerator is in normal use, the second optocoupler 12 can disconnect the working circuit of the first optocoupler 11, eliminating the energy consumption of the battery by the first optocoupler 11. The first optocoupler 11 corresponds to optocouplers U1, U5, U8, and U10 in the circuit, and the second optocoupler 12 corresponds to optocouplers U2, U7, U9, and U11 in the circuit.

[0037] The first detection circuit corresponding to the first battery access port CN1 includes an optocoupler U1 and an optocoupler U2. Pin 1 of optocoupler U1 is electrically connected to pin 3 of the first battery access port CN1. Pin 2 of optocoupler U1 is connected to pin 4 of optocoupler U2 after being connected in series with resistor R1. Pin 3 of optocoupler U1 is grounded. Pin 4 of optocoupler U1 is electrically connected between the positive terminal of diode D2 and resistor R4 in the relay drive circuit 3. Pin 1 of optocoupler U2 is connected to the output terminal of the auxiliary power supply step-down circuit 7 after being connected in series with resistor R3. Pin 2 of optocoupler U2 is grounded. Pin 3 of optocoupler U2 is electrically connected to pin 1 of the first battery access port CN1.

[0038] The second detection circuit corresponding to the second battery access port CN3 includes optocoupler U5 and optocoupler U7. Pin 1 of optocoupler U5 is electrically connected to pin 3 of the second battery access port CN3. Pin 2 of optocoupler U5 is connected to pin 4 of optocoupler U7 after being connected in series with resistor R9. Pin 3 of optocoupler U5 is grounded. Pin 4 of optocoupler U5 is electrically connected between the positive terminal of diode D3 and resistor R5 in the relay drive circuit 3. Pin 1 of optocoupler U7 is connected to the output terminal of the auxiliary power supply step-down circuit 7 after being connected in series with resistor R8. Pin 2 of optocoupler U7 is grounded. Pin 3 of optocoupler U7 is electrically connected to pin 1 of the second battery access port CN3.

[0039] The third detection circuit corresponding to the third battery access port CN4 includes optocoupler U8 and optocoupler U9. Pin 1 of optocoupler U8 is electrically connected to pin 3 of the third battery access port CN4. Pin 2 of optocoupler U8 is connected to pin 4 of optocoupler U9 after being connected in series with resistor R11. Pin 3 of optocoupler U8 is grounded. Pin 4 of optocoupler U8 is electrically connected between the positive terminal of diode D4 and resistor R6 in the relay drive circuit 3. Pin 1 of optocoupler U9 is connected to the output terminal of the auxiliary power supply step-down circuit 7 after being connected in series with resistor R10. Pin 2 of optocoupler U9 is grounded. Pin 3 of optocoupler U9 is electrically connected to pin 1 of the third battery access port CN4.

[0040] The fourth detection circuit corresponding to the fourth battery access port CN5 includes optocoupler U10 and optocoupler U11. Pin 1 of optocoupler U10 is electrically connected to pin 3 of the fourth battery access port CN5. Pin 2 of optocoupler U10 is connected to pin 4 of optocoupler U11 after being connected in series with resistor R13. Pin 3 of optocoupler U10 is grounded. Pin 4 of optocoupler U10 is electrically connected between the positive terminal of diode D5 and resistor R7 in the relay drive circuit 3. Pin 1 of optocoupler U11 is connected to the output terminal of the auxiliary power supply step-down circuit 7 after being connected in series with resistor R12. Pin 2 of optocoupler U11 is grounded. Pin 3 of optocoupler U11 is electrically connected to pin 1 of the fourth battery access port CN5.

[0041] Specifically, the relay drive circuit 3 includes a drive chip U3. Pins 1 to 8 of the drive chip U3 are signal input I / O ports. Pins 1 and 2 correspond to the first detection circuit and are electrically connected to the negative terminal of diode D2. Pins 3 and 4 correspond to the second detection circuit and are electrically connected to the negative terminal of diode D3. Pins 5 and 6 correspond to the third detection circuit and are electrically connected to the negative terminal of diode D4. Pins 7 and 8 correspond to the fourth detection circuit and are electrically connected to the negative terminal of diode D5. The positive terminals of diodes D2, D3, D4, and D5 are connected in series with resistors R4, R5, R6, and R7, respectively, and are all electrically connected to the output terminal of the auxiliary power supply step-down circuit 7. Pin 9 of the drive chip U3 is grounded, and pin 10... The auxiliary power supply step-down circuit 7 is electrically connected to the output terminal. Pins 11 to 18 of the driver chip U3 are signal output I / O ports, which are electrically connected to the corresponding relay pins in the relay module 4. Pin 11 of the driver chip U3 is electrically connected to pin 1 of relay RELAY1, pin 12 is electrically connected to pin 1 of relay RELAY2, pin 13 is electrically connected to pin 1 of relay RELAY3, pin 14 is electrically connected to pin 1 of relay RELAY4, pin 15 is electrically connected to pin 1 of relay RELAY5, pin 16 is electrically connected to pin 1 of relay RELAY6, pin 17 is electrically connected to pin 1 of relay RELAY7, and pin 18 is electrically connected to pin 1 of relay RELAY8.

[0042] Specifically, in the relay module 4, two relays are provided for each of the battery access ports 8. The relays in the relay module 4 are normally closed single-pole double-throw relays 13, such as... Figure 7 As shown, the normally closed relay enables the multi-battery management circuit to not increase battery power consumption when the vehicle refrigerator is in normal use.

[0043] Furthermore, the relay module 4 may also include a relay for each of the battery access ports 8. The relays in the relay module 4 are normally closed double-pole double-throw relays 14, such as... Figure 8 As shown.

[0044] Specifically, a magnet 15 is provided on the cover of the vehicle refrigerator battery compartment, and a magnetic switch 16 is provided inside the battery compartment corresponding to the magnet 15. The magnetic switch 16 is normally closed and is electrically connected to the auxiliary power supply circuit 6 through port CN2 or port CN10. When the cover of the vehicle refrigerator battery compartment is closed, the magnet 15 approaches the magnetic switch 16, and the normally closed magnetic switch 16 is in the open state. The MOSFET Q1 in the auxiliary power supply circuit 6 is de-energized, and the multi-battery management circuit does not... During operation, since the relay in relay module 4 is normally closed, battery power is normally transmitted from battery input module 1 to battery output module 5, and the vehicle refrigerator works normally. When installing or removing and replacing batteries, the cover of the vehicle refrigerator battery box is opened, the magnet 15 moves away from the magnetic control switch 16, and the normally closed magnetic control switch 16 returns to the closed state. When a battery is inserted into the battery socket and the battery box is not empty, the MOS transistor Q1 in the auxiliary power supply switching circuit 6 is energized, and the multi-battery management circuit starts to operate.

[0045] Specifically, the auxiliary power supply switching circuit 6 includes a MOSFET Q1. The auxiliary power supply switching circuit 6 has multiple parallel input terminals, each electrically connected to a corresponding pin of the output port 9. Each parallel input terminal of the auxiliary power supply switching circuit 6 is connected in series with a diode and then electrically connected to the source S of the MOSFET Q1. The gate G of the MOSFET Q1 is connected in series with a resistor R14 and a diode D15 and then electrically connected to pin 1 of the signal input port CN2 or port CN10 of the magnetic switch 16. A resistor R2, a Zener diode D10, and a capacitor C4 are connected in parallel between the source S and gate G of the MOSFET Q1. The anode of the Zener diode D10 is electrically connected to the gate G of the MOSFET Q1, and the cathode is electrically connected to the source S of the MOSFET Q1. The drain D of the MOSFET Q1 is the output terminal of the auxiliary power supply switching circuit 6 and is electrically connected to the auxiliary power supply buck circuit 7. The auxiliary power supply step-down circuit 7 includes a step-down chip U4. Pin 1 of the step-down chip U4 is connected in series with a resistor R15 and then electrically connected to the drain D of the MOSFET Q1. Capacitor C2 is connected in parallel with a polarized capacitor C5. One end of capacitor C2 is electrically connected to the positive terminal of polarized capacitor C5 between pin 1 of the step-down chip U4 and the resistor R15. The other end of capacitor C2 is grounded to the negative terminal of polarized capacitor C5. Pins 4 to 8 of the step-down chip U4 are all grounded. Pin 3 of the step-down chip U4 is electrically connected to the positive terminal of polarized capacitor C1, and the negative terminal of polarized capacitor C1 is grounded. Pin 2 of the step-down chip U4 is electrically connected to the negative terminal of rectifier diode D1 and one end of inductor L1, respectively. The positive terminal of rectifier diode D1 is grounded. The other end of inductor L1 is electrically connected to the positive terminal of polarized capacitor C1. The connection point between inductor L1 and the positive terminal of polarized capacitor C1 is the output terminal of the auxiliary power supply step-down circuit 7.

[0046] This patent also claims protection for a control method employing the above-described multi-battery management circuit, the specific operation of which is as follows:

[0047] When a battery holder with a battery inserted is in operation, the detection circuit 10 corresponding to the battery holder is turned on. The second optocoupler 12 in the detection circuit 10 is activated, and the loop of the first optocoupler 11 is turned on. The first optocoupler 11 is connected to the battery voltage and starts to work, pulling the level of the corresponding input I / O port in the relay drive circuit 3 low. The corresponding output I / O port in the relay drive circuit 3 outputs a high-level voltage to the corresponding relay pin. Since the other pin of the corresponding relay is also in a high-level state, the corresponding relay does not switch and remains in a normally closed state. The battery access port 8 and the output port 9 corresponding to the battery holder are normally connected.

[0048] When there is no battery inserted, the detection circuit 10 corresponding to the battery holder is not conducting. The second optocoupler 12 in the detection circuit 10 is working, and the first optocoupler 11 does not work because it cannot connect to the battery voltage. The corresponding input I / O port of the relay drive circuit 3 continuously inputs a high-level voltage signal, and the corresponding output I / O port of the relay drive circuit 3 outputs a low-level voltage to the corresponding relay pin. Since the other pin of the corresponding relay is in a high-level state, the corresponding relay works, switching the relay switch to the off state, so that the battery access port 8 and the output port 9 corresponding to the battery holder are disconnected, thereby making the battery holder without battery inserted unpowered and meeting the safety requirement of no harm to human body contact.

[0049] The embodiments described herein are merely preferred embodiments of the invention and are not intended to limit the inventive concept and scope. Any modifications and improvements made by those skilled in the art to the technical solutions of the invention without departing from the inventive concept should fall within the protection scope of the invention.

Claims

1. A multi-battery management circuit for a vehicle-mounted refrigerator, characterized in that: The system includes a battery input module (1) electrically connected to the electrodes of the battery holder in the car refrigerator. The battery input module (1) is electrically connected to a detection circuit module (2) for detecting whether the battery is installed and connected. The detection circuit module (2) is electrically connected to a relay drive circuit (3). The relay drive circuit (3) is electrically connected to a relay module (4). The relay module (4) is electrically connected to a battery output module (5) electrically connected to the main control board of the car refrigerator. The multi-battery management circuit also includes an auxiliary power on / off circuit (6) for controlling the power supply of the entire circuit system. The auxiliary power on / off circuit (6) is electrically connected to the battery input module (1). The auxiliary power on / off circuit (6) is electrically connected to an auxiliary power step-down circuit (7) for converting the battery voltage into the voltage required by the multi-battery management circuit. The output terminal of the auxiliary power step-down circuit (7) is electrically connected to the relay drive circuit (3) and the relay module (4) respectively. The vehicle refrigerator has multiple batteries connected in parallel. In the battery input module (1), each battery has a battery input port (8), and in the battery output module (5), each battery input port (8) has an output port (9). In the detection circuit module (2), a detection circuit (10) is provided for each of the battery access ports (8). A first optocoupler (11) for transmitting detection signals is provided in the detection circuit (10). The light-emitting diode pin in the first optocoupler (11) is electrically connected to the battery access port (8), and the output pin in the first optocoupler (11) is electrically connected to the relay drive circuit (3). The detection circuit (10) is further provided with a second optocoupler (12) for controlling the switching of the light-emitting diode in the first optocoupler (11) and reducing energy consumption. The light-emitting diode pin in the second optocoupler (12) is electrically connected to the output terminal of the auxiliary power supply step-down circuit (7), and the output pin in the second optocoupler (12) is connected to the circuit of the light-emitting diode pin in the first optocoupler (11).

2. The multi-battery management circuit for a vehicle refrigerator according to claim 1, characterized in that: The relay driving circuit (3) includes a driving chip U3. Pins 1 to 8 of the driving chip U3 are signal input I / O ports, which are electrically connected to the corresponding detection circuit (10). Pins 1 to 8 of the driving chip U3 are connected in series with a diode and a resistor, and then electrically connected to the output terminal of the auxiliary power supply step-down circuit (7). The connection point between the detection circuit (10) and the relay driving circuit (3) is located between the positive terminal of the diode and the resistor. Pin 9 of the driving chip U3 is grounded, and pin 10 is electrically connected to the output terminal of the auxiliary power supply step-down circuit (7). Pins 11 to 18 of the driving chip U3 are signal output I / O ports, which are electrically connected to the corresponding relay pins in the relay module (4).

3. The multi-battery management circuit for a vehicle refrigerator according to claim 1, characterized in that: In the relay module (4), two relays are provided for each of the battery access ports (8), and the relays in the relay module (4) are normally closed single-pole double-throw relays (13).

4. The multi-battery management circuit for a vehicle refrigerator according to claim 1, characterized in that: Each battery access port (8) in the relay module (4) is provided with a relay, and the relay in the relay module (4) is a normally closed double-pole double-throw relay (14).

5. The multi-battery management circuit for a vehicle refrigerator according to any one of claims 1 to 4, characterized in that: A magnet (15) is provided on the cover of the battery box of the vehicle refrigerator. A magnetic control switch (16) is provided inside the battery box corresponding to the magnet (15). The magnetic control switch (16) is normally closed. The magnetic control switch (16) is electrically connected to the auxiliary power supply circuit (6) through port CN2 or port CN10.

6. The multi-battery management circuit for a vehicle refrigerator according to claim 5, characterized in that: The auxiliary power supply switching circuit (6) includes a MOS transistor Q1. The auxiliary power supply switching circuit (6) has multiple parallel input terminals, each electrically connected to the corresponding output port (9) pin. The multiple parallel input terminals of the auxiliary power supply switching circuit (6) are connected in series with diodes and then electrically connected to the source S of the MOS transistor Q1. The gate G of the MOS transistor Q1 is connected in series with resistor R14 and diode D15 and then electrically connected to the signal input port CN2 or port CN10 pin 1 of the magnetic switch (16). A resistor R2, a Zener diode D10, and a capacitor C4 are connected in parallel between the source S and the gate G of the MOS transistor Q1. The positive terminal of the Zener diode D10 is electrically connected to the gate G of the MOS transistor Q1, and the negative terminal is electrically connected to the source S of the MOS transistor Q1. The drain D of the MOS transistor Q1 is the output terminal of the auxiliary power supply switching circuit (6) and is connected to the auxiliary power supply step-down circuit ( ). 7) Electrical connection: The auxiliary power supply step-down circuit (7) includes a step-down chip U4. Pin 1 of the step-down chip U4 is connected in series with resistor R15 and then electrically connected to the drain D of MOSFET Q1. Capacitor C2 is connected in parallel with polarized capacitor C5. One end of capacitor C2 is electrically connected to the positive terminal of polarized capacitor C5 between pin 1 of step-down chip U4 and resistor R15. The other end of capacitor C2 is grounded to the negative terminal of polarized capacitor C5. Pins 4 to 8 of step-down chip U4 are all grounded. Pin 3 of step-down chip U4 is electrically connected to the positive terminal of polarized capacitor C1. The negative terminal of polarized capacitor C1 is grounded. Pin 2 of step-down chip U4 is electrically connected to the negative terminal of rectifier diode D1 and one end of inductor L1 respectively. The positive terminal of rectifier diode D1 is grounded. The other end of inductor L1 is electrically connected to the positive terminal of polarized capacitor C1. The connection point between inductor L1 and the positive terminal of polarized capacitor C1 is the output terminal of the auxiliary power supply step-down circuit (7).

7. A control method employing the multi-battery management circuit of claim 6, characterized in that: This multi-battery management circuit can add or remove corresponding electronic components based on the number of batteries in the car refrigerator. Taking a car refrigerator with four batteries as an example, the working process of this multi-battery management circuit is as follows: When the battery compartment cover of the vehicle refrigerator is closed, the magnet (15) approaches the magnetic switch (16), and the normally closed magnetic switch (16) is in the open state. The MOS transistor Q1 in the auxiliary power supply switching circuit (6) is de-energized, and the multi-battery management circuit does not work. Since the relay in the relay module (4) is normally closed, the battery power is normally transmitted from the battery input module (1) to the battery output module (5), and the vehicle refrigerator works normally. When installing or removing and replacing the battery, the cover of the car refrigerator battery box is opened, the magnet (15) moves away from the magnetic control switch (16), and the normally closed magnetic control switch (16) returns to the closed state. When a battery is inserted into the battery socket and the battery box is not empty, the MOS transistor Q1 in the auxiliary power supply switching circuit (6) is energized, and the multi-battery management circuit starts to operate. The auxiliary power supply step-down circuit (7) reduces the battery voltage output to provide the appropriate voltage for the relay drive circuit (3), the detection circuit module (2), and the relay module (4) so ​​that they can work normally. When a battery holder with a battery inserted is connected, the detection circuit (10) corresponding to the battery holder is turned on, the second optocoupler (12) in the detection circuit (10) is working, the loop of the first optocoupler (11) is turned on, the first optocoupler (11) is connected to the battery voltage and starts to work, pulling the level of the corresponding input I / O port in the relay drive circuit (3) low, and the corresponding output I / O port in the relay drive circuit (3) outputs a high-level voltage to the corresponding relay pin. Since the other pin of the corresponding relay is also in a high-level state, the corresponding relay does not switch and remains in a normally closed state. The battery access port (8) and the output port (9) corresponding to the battery holder are normally connected. When there is no battery inserted, the detection circuit (10) corresponding to the battery holder is not conducting. The second optocoupler (12) in the detection circuit (10) is working. The first optocoupler (11) does not work because it cannot connect to the battery voltage. The corresponding input I / O port in the relay drive circuit (3) continuously inputs a high-level voltage signal. The corresponding output I / O port in the relay drive circuit (3) outputs a low-level voltage to the corresponding relay pin. Since the other pin of the corresponding relay is in a high-level state, the corresponding relay works and switches the relay switch to the open state, so that the battery access port (8) and the output port (9) corresponding to the battery holder are in a disconnected state, so that the battery holder without battery insertion is not charged, which meets the safety requirement of no harm to human body when touched.

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