US-20260128610-A1 - CURRENT SWITCHING DEVICE FOR EMERGENCY START POWER SUPPLY OF CAR

Abstract

Provided is a current switching device for an emergency start power supply of a car, including: a lithium battery voltage sampling circuit configured to collect a lithium battery voltage in the emergency start power supply; a battery voltage sampling circuit configured to collect a battery voltage of the car; a control module configured to output a first control signal and a second control signal based on the lithium battery voltage and the battery voltage; a precharging circuit configured to transmit lithium battery energy of the emergency start power supply into a battery based on a first current when the first control signal is at a high level; and a relay configured to transmit the lithium battery energy of the emergency start power supply into the battery based on a second current when the second control signal is at a high level.

Inventors

• YaoTian YAO
• KaiJian QIU
• JiongLang XU
• Di Zhang

Assignees

• Shenzhen Benrong New Energy Technology Co., Ltd

Dates

Publication Date

20260507

Application Date

20241126

Priority Date

20241104

Claims (10)

1. 1 . A current switching device for an emergency start power supply of a car, comprising: a lithium battery voltage sampling circuit configured to collect a lithium battery voltage in the emergency start power supply; a battery voltage sampling circuit configured to collect a battery voltage of the car; a control module configured to output a first control signal and a second control signal based on the lithium battery voltage and the battery voltage; a precharging circuit configured to transmit lithium battery energy of the emergency start power supply into a battery based on a first current when the first control signal is at a high level; and a relay configured to transmit the lithium battery energy of the emergency start power supply into the battery based on a second current when the second control signal is at a high level.
2. 2 . The current switching device for an emergency start power supply of a car according to claim 1 , wherein the current switching device further comprises a contact temperature sampling circuit configured to collect a contact temperature of the relay, wherein the contact temperature sampling circuit is connected to a control port of the control module.
3. 3 . The current switching device for an emergency start power supply of a car according to claim 2 , wherein the contact temperature sampling circuit comprises a thermistor NTC 5 and a capacitor C 102 , one end of the thermistor NTC 5 and one end of the capacitor C 102 are grounded, and the other end of the thermistor NTC 5 and the other end of the capacitor C 102 are connected and then are connected to the control port of the control module.
4. 4 . The current switching device for an emergency start power supply of a car according to claim 1 , wherein the current switching device further comprises an alarm circuit connected to a control port of the control module.
5. 5 . The current switching device for an emergency start power supply of a car according to claim 4 , wherein the alarm circuit comprises a buzzer BUZ 1 , and the buzzer BUZ 1 is connected to the control port of the control module.
6. 6 . The current switching device for an emergency start power supply of a car according to claim 1 , wherein the lithium battery voltage sampling circuit comprises a resistor R 142 and a resistor R 143 for voltage division, and the resistor R 142 and the resistor R 143 are connected in series, wherein the resistor R 142 is connected to a control port of the emergency start power supply.
7. 7 . The current switching device for an emergency start power supply of a car according to claim 5 , wherein the lithium battery voltage sampling circuit further comprises a diode ZD 14 , a capacitor C 105 , and a resistor R 141 , one end of the diode ZD 14 , one end of the capacitor C 105 , and one end of the resistor R 141 are connected and then are connected to the control port of the control module, the other end of the diode ZD 14 , the other end of the capacitor C 105 , and the resistor R 143 are grounded, and the other end of the resistor R 141 is connected between the resistor R 142 and the resistor R 143 .
8. 8 . The current switching device for an emergency start power supply of a car according to claim 1 , wherein the battery voltage sampling circuit comprises a resistor R 153 and a resistor R 154 for voltage division, and the resistor R 153 and the resistor R 154 are connected in series, wherein the resistor R 153 is connected to a positive electrode of the car battery.
9. 9 . The current switching device for an emergency start power supply of a car according to claim 7 , wherein the battery voltage sampling circuit further comprises a diode ZD 15 , a capacitor C 115 , and a resistor R 155 , one end of the diode ZD 15 , one end of the capacitor C 115 , and one end of the resistor R 155 are connected and then are connected to the control port of the control module, the other end of the capacitor C 115 , the other end of the diode ZD 15 , and the resistor R 154 are grounded, and the other end of the resistor R 155 is connected between the resistor R 153 and the resistor R 154 .
10. 10 . The current switching device for an emergency start power supply of a car according to claim 1 , wherein the current switching device further comprises an auxiliary power supply module configured to supply power to the control module.

Description

FIELD OF TECHNOLOGY The present utility model relates to the field of emergency start power supplies of cars, specifically to a current switching device for an emergency start power supply of a car. BACKGROUND With the improvement of living standards, the number of cars owned by people is increasing. Due to the wide variety of cars on the market, the quality of various parts, especially battery components, varies greatly. Moreover, various improper usage habits of different car owners easily lead to a decline in performance of a car battery, making it prone to low power and failing to ignite. In such a case, an emergency start power supply is needed to quickly release electrical energy from a lithium battery to the car battery in a short time, thereby helping start a car engine. The key component of an emergency power supply of a car is an intelligent switching circuit connected between a high-rate lithium battery and a car battery. The circuit not only requires instantaneous conduction of a current of more than 100 A to provide electrical energy required for car start, but also requires various comprehensive protection functions. At present, the solution of the intelligent switching circuit on the market is realized generally with a high-direct-current relay, which has great defects in technical design. First, the main circuit controls the on/off of a ground return circuit, which brings the inconvenience to voltage sampling for the car battery and reduces the time delay and accuracy of voltage sampling, thereby easily causing the start current to fail to meet the requirements; and secondly, the relay is not effectively protected, so that the relay contacts are easily adhered at a high temperature to lose the switching performance, thus greatly shortening the service life of the relay. SUMMARY To solve the problem of a decrease in time delay and accuracy of voltage sampling in the prior art, the present utility model provides a current switching device for an emergency start power supply of a car. A control module can conveniently and accurately sample a battery voltage of the car online, thereby stably implementing a function of emergency start of the car. To achieve the above objective, a specific solution adopted by the present utility model is as follows: A current switching device for an emergency start power supply of a car, including: a lithium battery voltage sampling circuit configured to collect a lithium battery voltage in the emergency start power supply;a battery voltage sampling circuit configured to collect a battery voltage of the car;a control module configured to output a first control signal and a second control signal based on the lithium battery voltage and the battery voltage;a precharging circuit configured to transmit lithium battery energy of the emergency start power supply into a battery based on a first current when the first control signal is at a high level; anda relay configured to transmit the lithium battery energy of the emergency start power supply into the battery based on a second current when the second control signal is at a high level. Preferably, the current switching device further includes a contact temperature sampling circuit configured to collect a contact temperature of the relay, where the contact temperature sampling circuit is connected to a control port of the control module. Preferably, the contact temperature sampling circuit includes a thermistor NTC5 and a capacitor C102, where one end of the thermistor NTC5 and one end of the capacitor C102 are grounded, and the other end of the thermistor NTC5 and the other end of the capacitor C102 are connected and then are connected to the control port of the control module. Preferably, the current switching device further includes an alarm circuit connected to the control port of the control module. Preferably, the alarm circuit includes a buzzer BUZ1, where the buzzer BUZ1 is connected to the control port of the control module. Preferably, the lithium battery voltage sampling circuit includes a resistor R142 and a resistor R143 for voltage division, and the resistor R142 and the resistor R143 are connected in series, where the resistor R142 is connected to a positive electrode of the emergency start power supply. Preferably, the lithium battery voltage sampling circuit further includes a diode ZD14, a capacitor C105, and a resistor R141, where one end of the diode ZD14, one end of the capacitor C105, and one end of the resistor R141 are connected and then are connected to the control port of the control module, the other end of the diode ZD14, the other end of the capacitor C105, and the resistor R143 are grounded, and the other end of the resistor R141 is connected between the resistor R142 and the resistor R143. Preferably, the battery voltage sampling circuit includes a resistor R153 and a resistor R154 for voltage division, and the resistor R153 and the resistor R154 are connected in series, where the resisto