Automobile starting battery protection circuit

Abstract

The utility model relates to an automobile starting battery protection circuit, which comprises an MCU main control module, an analog front end module, an MOS tube module, a switch module and a starting power supply module, the analog front end module is connected with a battery module, the MOS tube module is connected with a negative output end B-of the battery module through a current detection resistor Rs, and the switch module is connected with the starting power supply module. The analog front-end module is connected with two ends of the current detection resistor Rs, the MOS tube module is also connected with the analog front-end module and the starting power supply module, the MCU master control module is connected with a positive output end B + of a battery module through the switch module, and the MCU master control module is connected with the MOS tube module through the starting power supply module; by utilizing the overvoltage protection circuit, when the automobile starting battery is in an overvoltage state, the charging MOS tube can be quickly opened, so that the impact time of large current when the charging MOS tube is closed can be reduced, the charging MOS tube is further effectively protected, and the service life of the charging MOS tube can be effectively prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of automobile starting batteries, in particular to an automobile starting battery protection circuit. Background Art

[0002] At present, in the protection circuit of lithium iron phosphate starting battery, when the battery management system detects that the battery is in an overvoltage state, the analog front-end module detects that the discharge current will take a long time to turn on the charging MOS, which will cause the charging MOS tube to be subjected to a large current shock when it is turned off, thereby causing damage to the charging MOS tube; and when the battery is in an undervoltage protection state, the car cannot start under low voltage state.

[0003] Therefore, it is necessary to provide a technical solution that can solve the above problems. Utility Model Content

[0004] The utility model aims to provide a car starting battery protection circuit to solve the technical problem in the prior art that a charging MOS tube is easily damaged when the battery is in an over-state.

[0005] The technical solution provided by the utility model is:

[0006] A car starting battery protection circuit comprises an MCU main control module, an analog front-end module, a MOS tube module, a switch module and a starting power supply module, wherein the analog front-end module is connected to the battery module, the MOS tube module comprises a charging MOS tube QC and a discharging MOS tube QD, the gates of the charging MOS tube QC and the discharging MOS tube QD are connected to the analog front-end module, the MOS tube module is connected to the negative output terminal B- of the battery module through a current sensing resistor Rs, the analog front-end module is connected to both ends of the current sensing resistor Rs, the MOS tube module is also connected to the analog front-end module and the starting power supply module, the MCU main control module is connected to the positive output terminal B+ of the battery module through the switch module, the MCU main control module is connected to the MOS tube module through the starting power supply module, and the starting power supply module is also connected to the positive output terminal B+ of the battery module;

[0007] The switch module is used to control the switch state of the discharge MOS tube QD;

[0008] The startup power module is used to detect the voltage value across the current sensing resistor Rs. When the startup power module detects that the voltage of the current sensing resistor Rs is greater than a preset first voltage U1, the startup power module outputs a corresponding control signal to turn on the charging MOS tube QC.

[0009] The analog front-end module is used to detect the voltage of a single battery in the battery module. When the analog front-end module detects that the voltage of a single battery in the battery module is greater than a preset second voltage U2, the MCU main control module transmits a corresponding control signal to turn off the charging MOS tube QC.

[0010] In a preferred embodiment, the startup power supply module includes a voltage detection circuit for detecting the voltage across the current sensing resistor Rs, and a first switch circuit for controlling the charging MOS tube QC to be turned on or off.

[0011] In a preferred embodiment, the first switch circuit includes a first transistor Q1, the base of the first transistor Q1 is connected to the MCU main control module, the emitter of the first transistor Q1 is grounded, and the collector of the first transistor Q1 is connected to the MOS tube module;

[0012] The voltage detection circuit is provided with a first chip IC1, and the pin 4 and the pin 3 of the first chip are respectively connected to the two ends of the current detection resistor Rs through resistors. Preferably, the chip model of the first chip IC1 is GS8331.

[0013] In a preferred embodiment, the voltage value of the first voltage U1 is 0.7 mV, and the voltage value of the second voltage U2 is 3.9V.

[0014] In a preferred embodiment, the switch module is provided with a second switch circuit for controlling the switch state of the discharge MOS tube QD, and a forced start switch circuit for controlling the normal output of the battery module within a preset time T1. Preferably, the preset time T1 is 2-3 minutes.

[0015] In a preferred embodiment, the second switch circuit includes a second transistor Q2, the base of the second transistor Q2 is connected to the forced start switch circuit through a resistor, the emitter of the second transistor Q2 is grounded, and the collector of the second transistor Q2 is connected to the MCU main control module through a resistor;

[0016] The forced start switch circuit includes a switch K, a positive connection end of the switch K is connected to the positive output end B+ of the battery module through a resistor, and a negative connection end of the switch K is connected to the base of the second transistor Q2 through a resistor.

[0017] In a preferred embodiment, the automobile starting battery protection circuit further includes a heating module for heating the battery module, and the heating module is connected to the MCU main control module, the MOS tube module and the positive output end of the battery module.

[0018] In a preferred embodiment, the battery module is a lithium iron phosphate starting battery used for starting a car.

[0019] Compared with the prior art, the automobile starting battery protection circuit provided by the utility model has the following beneficial effects:

[0020] When the car starting battery is in an overvoltage state, the charging MOS tube can be quickly turned on, thereby reducing the impact time of the large current when the charging MOS tube is turned off, thereby effectively protecting the charging MOS tube and effectively improving the life of the charging MOS tube; when the car starting battery is in an undervoltage protection state, the switch K in the forced start switch circuit is operated to enable the battery module to output the working voltage / working current normally within the preset time T1, so that the battery can be started even if it is in an undervoltage protection state. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic block diagram of the circuit structure of the automobile starting battery protection circuit according to an embodiment of the utility model;

[0022] Figure 2 This is a schematic block diagram of the circuit structure of the MOS tube module described in the embodiment of the utility model;

[0023] Figure 3 A specific circuit diagram of the starting power supply module described in the embodiment of the utility model;

[0024] Figure 4 A specific circuit diagram of the switch module described in the embodiment of the utility model;

[0025] Figure 5 It is a specific circuit diagram of the MCU main control module described in the embodiment of the utility model;

[0026] Figure 6 It is a specific circuit diagram of the heating module described in the embodiment of the utility model. DETAILED DESCRIPTION

[0027] In order to better understand the purpose, technical solution and technical effect of the utility model, the utility model is further explained in conjunction with the accompanying drawings and embodiments. At the same time, it is stated that the embodiments described below are only used to explain the utility model and are not used to limit the utility model.

[0028] Example 1

[0029] like Figure 1-6As shown, a car starting battery protection circuit includes an MCU main control module, an analog front-end module, a MOS tube module, a switch module and a starting power supply module, wherein the analog front-end module is connected to the battery module, the MOS tube module includes a charging MOS tube QC and a discharging MOS tube QD, the gates of the charging MOS tube QC and the discharging MOS tube QD are connected to the analog front-end module, the MOS tube module is connected to the negative output terminal B- of the battery module through a current sensing resistor Rs, the analog front-end module is connected to both ends of the current sensing resistor Rs, the MOS tube module is also connected to the analog front-end module and the starting power supply module, the MCU main control module is connected to the positive output terminal B+ of the battery module through the switch module, the MCU main control module is connected to the MOS tube module through the starting power supply module, and the starting power supply module is also connected to the positive output terminal B+ of the battery module;

[0030] The switch module is used to control the switch state of the discharge MOS tube QD;

[0031] The startup power module is used to detect the voltage value across the current sensing resistor Rs. When the startup power module detects that the voltage of the current sensing resistor Rs is greater than a preset first voltage U1, the startup power module outputs a corresponding control signal to turn on the charging MOS tube QC.

[0032] The analog front-end module is used to detect the voltage of a single battery in the battery module. When the analog front-end module detects that the voltage of a single battery in the battery module is greater than a preset second voltage U2, the MCU main control module transmits a corresponding control signal to turn off the charging MOS tube QC.

[0033] In this embodiment, the analog front-end module is used to collect voltage / current information in the battery module, and through the use of the MCU main control module and other functional modules, it realizes overvoltage protection, undervoltage protection, charge and discharge overcurrent protection, short circuit protection and other functions. In a specific embodiment, the battery module is a lithium iron phosphate starting battery for starting a car; the analog front-end module and the MCU main control module are existing technologies or functional modules that can be realized by existing technologies, and their specific composition and working principle are not described here. In a specific embodiment, the specific circuit diagram of the MCU main control module is shown in the attached figure. Figure 5 shown.

[0034] In this embodiment, the MOS tube module includes a charging MOS tube QC and a discharging MOS tube QD. The circuit principle is as shown in the attached figure. Figure 2 As shown, the MOS tube module is used to realize the charging or discharging management of the battery module. The MOS tube module is a functional module of the prior art or that can be realized by the prior art, and its specific composition and working principle will not be described here.

[0035] In a preferred embodiment, the startup power supply module includes a voltage detection circuit for detecting the voltage across the current-sensing resistor Rs, and a first switch circuit for controlling the charging MOS tube QC to be turned on or off. The startup power supply module is used to control the charging MOS tube QC to be turned on (opened) by the first switch circuit when the battery module is in an overvoltage state and detects that the voltage across the current-sensing resistor Rs (in this embodiment, the resistance of the current-sensing resistor Rs is 0.05 milliohms) is greater than a certain value (0.7mV), thereby reducing the impact time of the large current when the charging MOS tube is turned off, thereby effectively protecting the charging MOS tube. The resistance of the current-sensing resistor Rs is 0.05 milliohms. When the voltage across the current-sensing resistor Rs is greater than 0.7mV, it proves that the current passing through the current-sensing resistor Rs is greater than 14A at this time. Therefore, it is necessary to control the charging MOS tube QC to be turned on (opened) at this time to effectively protect the charging MOS tube. Of course, the resistance value of the current-sensing resistor Rs can also be a numerical value. When the resistance value of the current-sensing resistor Rs is another resistance value Rx, the voltage value of the first voltage U1 is I*Rx. In this embodiment, I=14A.

[0036] In a specific embodiment, as shown in the attached Figure 3 As shown, the first switch circuit includes a first transistor Q1, the base of the first transistor Q1 is connected to the MCU main control module, the emitter of the first transistor Q1 is grounded, and the collector of the first transistor Q1 is connected to the MOS tube module;

[0037] The voltage detection circuit is provided with a first chip IC1, and the pin 4 and the pin 3 of the first chip are respectively connected to the two ends of the current detection resistor Rs through resistors. Preferably, the chip model of the first chip IC1 is GS8331.

[0038] In a preferred embodiment, the voltage value of the first voltage U1 is 0.7 mV, and the voltage value of the second voltage U2 is 3.9 V. Of course, the voltage value of the first voltage U1 and the voltage value of the second voltage U2 can be set according to specific needs. It should be noted that in the solution of this patent application, determining the voltage value of the first voltage U1 and the voltage value of the second voltage U2 is a prior art, and the solution in this patent application does not involve improvements to computer programs or algorithms.

[0039] In a preferred embodiment, the switch module is provided with a second switch circuit for controlling the switch state of the discharge MOS tube QD, and a forced start switch circuit for controlling the normal output of the battery module within a preset time T1. Through the forced start switch circuit, when the car starting battery is in an undervoltage protection state, the switch K in the forced start switch circuit is operated, so that the battery module can output the working voltage / working current normally within the preset time T1, so that the car can be started even when the battery is in an undervoltage protection state. Preferably, the preset time T1 is 2-3 minutes. Of course, the value of the preset time T1 can be set according to specific needs, as long as there is enough time to start the car.

[0040] In a specific embodiment, as shown in the attached Figure 4 As shown, the second switch circuit includes a second transistor Q2, the base of the second transistor Q2 is connected to the forced start switch circuit through a resistor, the emitter of the second transistor Q2 is grounded, and the collector of the second transistor Q2 is connected to the MCU main control module through a resistor;

[0041] The forced start switch circuit includes a switch K, a positive connection end of the switch K is connected to the positive output end B+ of the battery module through a resistor, and a negative connection end of the switch K is connected to the base of the second transistor Q2 through a resistor.

[0042] In a preferred embodiment, the automobile starting battery protection circuit also includes a heating module for heating the battery module, and the heating module is connected to the MCU main control module, the MOS tube module and the positive output terminal of the battery module. When the battery module is in a low temperature environment, the battery module can be heated by the heating module before charging the battery, so that the battery can be charged at a normal temperature to ensure the safety of battery charging. The heating module is a prior art or a functional module that can be implemented by the prior art, and its specific composition and working principle are not described here. In a specific embodiment, the specific circuit diagram of the heating module is shown in the attached figure. Figure 6 shown.

[0043] The following is a brief description of the working process of the automobile starting battery protection circuit provided in this embodiment:

[0044] Under normal working conditions, the pin 1 of the first chip IC1 chip of the voltage detection circuit in the startup power module is at a low level, and the charging MOS tube QC will not be turned on at this time;

[0045] When the voltage detection circuit detects that the voltage across the current detection resistor Rs is greater than 0.7mV, the pin 1 of the first chip IC1 outputs a high level, the first transistor Q1 is turned on, and the charging MOS tube QC is turned on; thereby, the following functions can be achieved: when the car starting battery is in an overvoltage state, the charging MOS tube can be quickly turned on, thereby reducing the impact time of a large current when the charging MOS tube is turned off, thereby effectively protecting the charging MOS tube, and effectively improving the life of the charging MOS tube;

[0046] When the analog front-end module detects that the voltage of a single battery cell is greater than 3.9V, the pin ST-DS of the MCU main control module outputs a high level, pulls down the level of pin 1 of the first chip IC1, and prohibits turning on the charging MOS tube QC, thereby protecting the battery from being charged again and ensuring the safety of battery use.

[0047] When the car starting battery is in the undervoltage protection state, the switch K in the forced start switch circuit is operated to open the switch K, so that the battery module can output the working voltage / working current normally within the preset time T1, so that the car can be started even if the battery is in the undervoltage protection state.

[0048] The above embodiments only express several implementation methods of the utility model, and the descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the inventive concept of the utility model, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A car starting battery protection circuit, characterized in that: It includes an MCU main control module, an analog front-end module, a MOS tube module, a switch module and a startup power supply module. The analog front-end module is connected to the battery module. The MOS tube module includes a charging MOS tube QC and a discharging MOS tube QD. The gates of the charging MOS tube QC and the discharging MOS tube QD are connected to the analog front-end module. The MOS tube module is connected to the negative output terminal B- of the battery module through a current sensing resistor Rs. The analog front-end module is connected to both ends of the current sensing resistor Rs. The MOS tube module is also connected to the analog front-end module and the startup power supply module. The MCU main control module is connected to the positive output terminal B+ of the battery module through the switch module. The MCU main control module is connected to the MOS tube module through the startup power supply module. The startup power supply module is also connected to the positive output terminal B+ of the battery module. The switch module is used to control the switch state of the discharge MOS tube QD; The startup power module is used to detect the voltage value across the current sensing resistor Rs. When the startup power module detects that the voltage of the current sensing resistor Rs is greater than a preset first voltage U1, the startup power module outputs a corresponding control signal to turn on the charging MOS tube QC. The analog front-end module is used to detect the voltage of a single battery in the battery module. When the analog front-end module detects that the voltage of a single battery in the battery module is greater than a preset second voltage U2, the MCU main control module transmits a corresponding control signal to turn off the charging MOS tube QC.

2. The automobile starting battery protection circuit according to claim 1, characterized in that: The startup power supply module includes a voltage detection circuit for detecting the voltage across the current detection resistor Rs, and a first switch circuit for controlling the charging MOS tube QC to be turned on or off.

3. The automobile starting battery protection circuit according to claim 2, characterized in that: The first switch circuit includes a first transistor Q1, the base of the first transistor Q1 is connected to the MCU main control module, the emitter of the first transistor Q1 is grounded, and the collector of the first transistor Q1 is connected to the MOS tube module; The voltage detection circuit is provided with a first chip IC1, and pins 4 and 3 of the first chip are connected to two ends of the current detection resistor Rs through resistors respectively.

4. The automobile starting battery protection circuit according to claim 3, characterized in that: The chip model of the first chip IC1 is GS8331.

5. The automobile starting battery protection circuit according to claim 1, characterized in that: The voltage value of the first voltage U1 is 0.7 mV, and the voltage value of the second voltage U2 is 3.9V.

6. The automobile starting battery protection circuit according to claim 1, characterized in that: The switch module is provided with a second switch circuit for controlling the switch state of the discharge MOS tube QD, and a forced start switch circuit for controlling the normal output of the battery module within a preset time T1.

7. The automobile starting battery protection circuit according to claim 6, characterized in that: The second switch circuit includes a second transistor Q2, the base of the second transistor Q2 is connected to the forced start switch circuit through a resistor, the emitter of the second transistor Q2 is grounded, and the collector of the second transistor Q2 is connected to the MCU main control module through a resistor; The forced start switch circuit includes a switch K, a positive connection end of the switch K is connected to the positive output end B+ of the battery module through a resistor, and a negative connection end of the switch K is connected to the base of the second transistor Q2 through a resistor.

8. The automobile starting battery protection circuit according to claim 7, characterized in that: The preset time T1 is 2-3 minutes.

9. The automobile starting battery protection circuit according to claim 1, characterized in that: The automobile starting battery protection circuit also includes a heating module for heating the battery module, and the heating module is connected to the MCU main control module, the MOS tube module and the positive output end of the battery module.

10. The automobile starting battery protection circuit according to claim 1, characterized in that: The battery module is a lithium iron phosphate starting battery used for starting a car.

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