Storage battery charging protection device and vehicle

Abstract

The utility model discloses a storage battery charging protection device and a vehicle, the device comprises a first wiring terminal, a protection circuit and a second wiring terminal, the first wiring terminal is used for being connected with a charging device; the second wiring terminal is used for being connected with the positive electrode of the storage battery, and no load exists between the second wiring terminal and the storage battery; the protection circuit comprises a charging on-off module, a current sampling module and a judgment module, and the judgment module is used for conducting the charging on-off module when it is determined that the charging current is smaller than a preset current threshold value according to the reference voltage and the charging voltage collected by the current collecting module, so that a charging loop is formed between the charging device and the storage battery; and the charging device charges the storage battery. The charging device of the device charges the storage battery, and when the storage battery is lack of electricity, equivalent current can be effectively inhibited, overlarge current charging is avoided, and the service life of the storage battery is greatly prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a battery charging protection device and a vehicle. Background Art

[0002] There are an increasing number of car brands and types, and both fuel-powered and new energy vehicles generally use batteries to power the vehicle's low-voltage systems. When the vehicle is turned off, most of the onboard equipment is powered off, but some remain in a low-power standby state, completely powered by the battery. The battery's charge and voltage will continue to decrease. When the vehicle is started, fuel-powered vehicles charge the battery through the generator; new energy vehicles use high-voltage DC-DC (Direct Current to Direct Current) to reduce the high voltage of the power battery and charge the battery. After the vehicle is started, the output voltage of the generator or high-voltage DC-DC will have a large voltage difference with the battery voltage, resulting in a period of excessively high limiting current, which can easily damage the battery. Utility Model Content

[0003] The present invention aims to solve, at least to a certain extent, one of the technical problems in the related art. To this end, one purpose of the present invention is to provide a battery charging protection device that can effectively suppress the equivalent current when the battery is low on power, avoid excessive current charging, and significantly extend the battery life.

[0004] The second object of the present invention is to provide a vehicle.

[0005] To achieve the above objectives, the first embodiment of the present invention provides a battery charging protection device, the device comprising: a first wiring terminal, a protection circuit, and a second wiring terminal, the first wiring terminal being configured to be connected to a charging device; the second wiring terminal being configured to be connected to a positive electrode of a battery, with no load between the second wiring terminal and the battery; the protection circuit comprising a charging on-off module, a current sampling module, and a judgment module, wherein a first end of the charging on-off module is connected to the first wiring terminal, a second end of the charging on-off module is connected to a first end of the current sampling module, a second end of the current sampling module is connected to the second wiring terminal, a third end of the current sampling module is connected to a first end of the judgment module, the first wiring terminal is connected to a second end of the judgment module, and a third end of the charging on-off module is connected to a third end of the judgment module. The judgment module is configured to, when it is determined based on a reference voltage and a charging voltage collected by the current collection module that the charging current is less than a preset current threshold, turn on the charging on-off module to form a charging circuit between the charging device and the battery, so that the charging device charges the battery.

[0006] According to the embodiment of the present invention, the judgment module in the battery charging protection device determines that the charging current is less than a preset current threshold based on the reference voltage and the charging voltage collected by the current collection module, and turns on the charging on-off module to connect the charging circuit formed between the charging device and the battery. As a result, when the charging device charges the battery, even if the battery is low on power, the equivalent current can be effectively suppressed to avoid excessive current charging, thereby greatly extending the battery life.

[0007] In addition, the battery charging protection device proposed in the above embodiment of the present invention may also have the following additional technical features:

[0008] According to one embodiment of the present utility model, the charging on-off module includes a first PMOS tube, a second PMOS tube and a first resistor, the drain of the first PMOS tube and the drain of the second PMOS tube are connected to the first end of the charging on-off module, the source of the first PMOS tube and the source of the second PMOS tube are connected to the second end of the charging on-off module, the gate of the first PMOS tube and the gate of the second PMOS tube are connected to the third end of the charging on-off module, and a first resistor is connected between the drain of the second PMOS tube and the gate of the second PMOS tube.

[0009] According to one embodiment of the present utility model, the current sampling module includes a second resistor, a first capacitor, a third resistor, a current sensor, a fourth resistor and a second capacitor, wherein the first end of the second resistor is connected to the first end of the current sampling module, the second end of the second resistor is connected to the second end of the current sampling module, the first end of the second resistor is connected to the first end of the first capacitor, the second end of the first capacitor is connected to the first end of the third resistor, the second end of the third resistor is connected to the second end of the second resistor, the first end of the first capacitor is connected to the SENSE+ end of the current sensor, the second end of the first capacitor is connected to the SENSE- end of the current sensor, the output end of the current sensor is connected to the first end of the fourth resistor, the second end of the fourth resistor is grounded, the output end of the current sensor is connected to the first end of the second capacitor, the second end of the second capacitor is grounded, and the output end of the current sensor is connected to the third end of the current sampling module; the current sensor is used to collect the current passing through the second resistor to determine the charging voltage.

[0010] According to an embodiment of the present utility model, the judgment module includes a fifth resistor, a sixth resistor, a seventh resistor, a third capacitor, a comparator, a first NMOS transistor, an eighth resistor, a fourth capacitor, a ninth resistor, a tenth resistor, an eleventh resistor, a fifth capacitor and a twelfth resistor, wherein the first end of the fifth resistor is connected to the second end of the judgment module, the second end of the fifth resistor is connected to the first end of the sixth resistor, the second end of the sixth resistor is connected to the positive input end of the comparator, the second end of the fifth resistor is connected to the first end of the seventh resistor, the second end of the seventh resistor is connected to the first end of the third capacitor, the second end of the seventh resistor is connected to ground, the second end of the third capacitor is connected to the second end of the sixth resistor, the ground end of the comparator is grounded, the first end of the eighth resistor is connected to the first wiring terminal, the second end of the eighth resistor is connected to the power supply end of the comparator, the second end of the eighth resistor is connected to the first end of the fourth capacitor, the second end of the four capacitors is grounded, the negative input end of the comparator is connected to the first end of the ninth resistor, the second end of the ninth resistor is connected to the first end of the judgment module, the first end of the tenth resistor is connected to the first wiring terminal, and the second end of the tenth resistor is connected to the output end of the comparator. The output end of the comparator is connected to the first end of the eleventh resistor, the second end of the eleventh resistor is grounded, the output end of the comparator is connected to the gate of the first NMOS tube, the drain of the first NMOS tube is grounded, the source of the first NMOS tube is connected to the first end of the twelfth resistor, the second end of the twelfth resistor is connected to the third end of the judgment module, the first end of the fifth capacitor is connected to the first wiring terminal, and the second end of the fifth capacitor is connected to the second end of the twelfth resistor; the positive input end of the comparator is used to detect the reference voltage, and the negative input end of the comparator is used to detect the voltage of the pass The comparator is configured to determine, when the voltage at the positive input terminal is greater than the voltage at the negative input terminal, that the charging current is less than a preset current threshold, output a high level, turn on the first NMOS transistor, and thereby turn on the first PMOS transistor and the second PMOS transistor, thereby conducting a charging circuit between the charging device and the battery; and, when the voltage at the positive input terminal is less than the voltage at the negative input terminal, determine that the charging current is greater than the preset current threshold, output a low level, turn off the first NMOS transistor, and thereby turn off the first PMOS transistor and the second PMOS transistor, thereby disconnecting the charging circuit between the charging device and the battery.

[0011] According to one embodiment of the present utility model, the first terminal is connected to the load, and the protection circuit includes a discharge on-off module and a drive module, the first end of the discharge on-off module is connected to the first terminal, the second end of the discharge on-off module is connected to the second terminal, the first end of the drive module is connected to the first terminal, and the second end of the drive module is connected to the second terminal. The drive module is driven and connected to the discharge on-off module, and the drive module is configured to turn on the discharge on-off module when detecting that the voltage of the first terminal is lower than the voltage of the second terminal, so that a discharge circuit is formed between the load and the battery, and the battery discharges to the load.

[0012] According to one embodiment of the present utility model, the driving module is an NMOS driver, and the discharge on-off module includes a second NMOS tube, a third NMOS tube, and a fourth NMOS tube. The source of the second NMOS tube, the source of the third NMOS tube, and the source of the fourth NMOS tube are connected to the first end of the discharge on-off module, the drain of the second NMOS tube, the drain of the third NMOS tube, and the drain of the fourth NMOS tube are connected to the second end of the discharge on-off module, the CATHODE end of the NMOS driver is connected to the first end of the driving module, the VCAP end of the NMOS driver is connected to the second end of the driving module through a sixth capacitor and the EN end of the NMOS driver, and the source of the second NMOS tube, the source of the third NMOS tube, and the source of the fourth NMOS tube are connected to the CATHODE end of the NMOS driver. The gate of the second NMOS transistor, the gate of the third NMOS transistor, and the gate of the fourth NMOS transistor are connected to the GATE terminal of the NMOS driver, the drain of the second NMOS transistor, the drain of the third NMOS transistor, and the drain of the fourth NMOS transistor are connected to the ANODE terminal of the NMOS driver, and the GND terminal of the NMOS driver is grounded; the NMOS driver is used to turn on the second NMOS transistor, the third NMOS transistor, and the fourth NMOS transistor when detecting that the voltage of the CATHODE terminal is lower than the voltage of the ANODE terminal, so as to conduct the discharge circuit formed by the load and the battery; and turn off the second NMOS transistor, the third NMOS transistor, and the fourth NMOS transistor when detecting that the voltage of the CATHODE terminal is higher than the voltage of the ANODE terminal, so as to disconnect the discharge circuit formed by the load and the battery.

[0013] According to an embodiment of the present invention, the second terminal is connected to the first end of the seventh capacitor, and the second end of the seventh capacitor is grounded.

[0014] According to an embodiment of the present invention, the first NMOS transistor continuously carries a current of 20A and a peak current of 100A.

[0015] According to an embodiment of the present invention, the second NMOS transistor, the third NMOS transistor, and the fourth NMOS transistor can continuously carry a current of 50A and a peak current of 230A.

[0016] To achieve the above-mentioned purpose, the second embodiment of the present invention proposes a vehicle, comprising a charging device, a battery and a battery charging protection device as proposed in the first embodiment of the present invention, wherein the charging device is connected to the positive pole of the battery through the battery charging protection device, and there is no load between the battery charging protection device and the battery.

[0017] Additional aspects and advantages of the present invention will be given in part in the following description and in part will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of a battery charging protection device according to an embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of the connection between the battery charging protection device, the charging module and the battery according to one embodiment of the utility model;

[0020] FIG3( a ) is a schematic diagram showing the connection between a battery charging protection device, a charging module and a battery according to a specific embodiment of the present invention;

[0021] FIG3( b ) is a schematic diagram of another embodiment of the present invention showing the connection between the battery charging protection device, the charging module and the battery;

[0022] Figure 4 is a schematic diagram of a battery charging protection device according to another embodiment of the present invention;

[0023] Figure 5 This is a circuit diagram of a battery charging protection device according to a specific embodiment of the present invention;

[0024] Figure 6 This is a simulation waveform diagram of different charging currents of an embodiment of the present utility model;

[0025] Figure 7 It is a schematic diagram of a vehicle according to an embodiment of the present utility model. DETAILED DESCRIPTION

[0026] The following describes in detail embodiments of the present invention, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0027] It's important to note that when a fuel-powered vehicle is turned off, the engine stops, and the battery powers dormant components. As the battery consumes energy, its voltage gradually decreases. If the vehicle is parked for an extended period, the voltage difference between the alternator's output voltage and the battery's voltage can become significant when restarted. This can result in excessively high limiting currents for a period of time, potentially damaging the battery. The alternator itself can also sustain some damage when outputting limiting current, and the output voltage can become unstable, potentially causing malfunctions in vehicle components.

[0028] New energy vehicles also face the problem of a gradual drop in battery voltage during parking. However, the high-voltage isolated DC-DC converter (DC-DC) that converts high voltage to low voltage has a fixed power output and a constant output voltage. When parked for extended periods, the battery voltage is significantly lower than the DC-DC converter, resulting in a significant charging current that can damage the battery and reduce its service life. The DC-DC converter simultaneously charges the battery and provides power to other components. When the battery requires high current, the DC-DC converter operates at its maximum power output, exposing the DC-DC converter, the outlet cable, and even the high-voltage wiring harness to overheating.

[0029] In order to solve the above problems, the embodiments of the present invention provide a battery charging protection device and a vehicle. The battery charging protection device and the vehicle of the embodiments of the present invention are described in detail below in conjunction with the drawings and specific implementation methods of the specification.

[0030] Figure 1 This is a schematic diagram of a battery charging protection device according to an embodiment of the present invention. Figure 1 As shown, the battery charging protection device 100 may include: a first terminal J1, a protection circuit and a second terminal J2.

[0031] The first terminal J1 is used to connect to the charging device;

[0032] The second terminal J2 is used to connect to the positive electrode of the battery, and there is no load between the second terminal J2 and the battery;

[0033] The protection circuit includes a charging on-off module 10, a current sampling module 20, and a judgment module 30. A first end of the charging on-off module 10 is connected to a first terminal J1, a second end of the charging on-off module 10 is connected to a first end of the current sampling module 20, a second end of the current sampling module 20 is connected to a second terminal J2, a third end of the current sampling module 20 is connected to a first end of the judgment module 30, the first terminal J1 is connected to a second end of the judgment module 30, and a third end of the charging on-off module 10 is connected to a third end of the judgment module 30. The judgment module 30 is configured to turn on the charging on-off module 10 when it is determined, based on a reference voltage and the charging voltage collected by the current collection module 20, that the charging current is less than a preset current threshold, thereby forming a charging circuit between the charging device and the battery, and the charging device charging the battery.

[0034] Specifically, the battery charging protection device 100 consists of a first terminal J1, a protection circuit, and a second terminal J2. The first terminal J1 is connected to the charging device, and the second terminal J2 is connected to the positive terminal of the battery. The battery charging protection device 100 of the present embodiment is installed near the positive terminal of the battery. There is no load between the battery and the charging device. The load is installed on the power supply or branch line between the charging device and the battery charging protection device 100. Figure 2 .

[0035] The protection circuit of this embodiment of the utility model includes a charging on-off module 10, a current sampling module 20, and a judgment module 30. One end of the charging on-off module 10 is connected to the first terminal J1, and the other end is connected to the second terminal J2 through the current sampling module 20. The current sampling module 20 can collect the charging current input by the charging device to the battery and convert the collected charging current into a charging voltage. The judgment module 30 then determines whether the charging current is less than a preset current threshold based on the charging voltage and a reference voltage.

[0036] If the reference voltage is greater than the charging voltage, it is determined that the charging current is less than the preset current threshold, and the charging on-off module 10 is controlled to be turned on, thereby completing the charging circuit formed between the charging device and the battery, and the charging device charges the battery.

[0037] If the reference voltage is lower than the charging voltage, it is determined that the charging current is greater than the preset current threshold, and the charging on-off module 10 is controlled to be disconnected, thereby disconnecting the charging circuit formed between the charging device and the battery, and the charging device does not charge the battery.

[0038] The charging device in the embodiment of the present invention can be a generator, see Figure 3(a). The charging device in the embodiment of the present invention can also be a charging device composed of a power battery and a high-voltage isolated DC-DC, see Figure 3(b).

[0039] The first terminal J1 and the second terminal J2 of the embodiment of the present invention are terminal blocks. For example, the first terminal J1 can be connected to a high-voltage isolated DC / DC output, and the second terminal J2 can be connected to a positive electrode of a battery.

[0040] The battery charging protection device of the embodiment of the utility model utilizes a judgment module to judge whether the charging current is less than a preset current threshold value based on a reference voltage and the charging voltage collected by a current collection module, and turns on or off the electrical on-off module to connect or disconnect the charging circuit formed between the charging device and the battery. As a result, when the charging device is charging the battery, even if the battery is low on power, the equivalent current can be effectively suppressed to avoid excessive current charging, thereby greatly extending the service life of the battery.

[0041] In a specific embodiment of the present invention, Figure 4 As shown, the first terminal J1 is connected to the load, and the protection circuit includes a discharge on-off module 40 and a driving module 50. The first end of the discharge on-off module 40 is connected to the first terminal J1, and the second end of the discharge on-off module 40 is connected to the second terminal J2. The first end of the driving module 50 is connected to the first terminal J1, and the first end of the driving module 50 is connected to the second terminal J2. The driving module 50 is driven and connected to the discharge on-off module 40. When the driving module 50 detects that the voltage of the first terminal J1 is lower than that of the second terminal J2, it turns on the discharge on-off module 40, so that a discharge circuit is formed between the load and the battery, and the battery discharges to the load.

[0042] The battery of the embodiment of the present utility model discharges the load through the discharge on-off module 40 and the drive module 50 .

[0043] Specifically, the voltage of the first terminal J1 is the load side or charging side voltage, and the voltage of the second terminal J2 is the battery voltage.

[0044] If the voltage at the first terminal J1 is lower than the voltage at the second terminal J2, the battery voltage is higher than the load voltage, and the battery is discharging. Upon detecting that the voltage at the first terminal J1 is lower than the voltage at the second terminal J2, the driver module 50 turns on the discharge on-off module 40, completing the discharge circuit between the load and the battery, allowing the battery to discharge into the load.

[0045] If the voltage at the first terminal J1 is greater than the voltage at the second terminal J2, it indicates that the battery voltage is lower than the charging voltage and the battery needs to be charged. Upon detecting that the voltage at the first terminal J1 is greater than the voltage at the second terminal J2, the driver module 50 turns off the discharge on-off module 40 to disconnect the discharge circuit between the load and the battery.

[0046] The battery charging protection device of the embodiment of the present utility model controls the discharge circuit formed between the second terminal J2, the discharge on-off module 40, the drive module 50 and the first terminal J1, and the on-off of the charging circuit formed between the first terminal J1, the charge on-off module 10, the current sampling module 20, the judgment module 30 and the second terminal J2, so as to achieve a small equivalent current when the battery is charged without affecting the external discharge current of the battery.

[0047] The battery charging protection device 100 of the embodiment of the present invention mainly protects the battery by using devices such as a comparator, a current sensor, an NMOS driver, and a MOSFET (metal oxide field effect transistor) to prevent high current charging from damaging the battery and the charging device. The circuit schematic diagram of the battery charging protection device 100 is shown in FIG. Figure 4 shown.

[0048] In a specific embodiment of the present invention, Figure 5 As shown, the charging on-off module 10 includes a first PMOS transistor Q1, a second PMOS transistor Q2 and a first resistor R1. The drain of the first PMOS transistor Q1 and the drain of the second PMOS transistor Q2 are connected to the first end of the charging on-off module 10, the source of the first PMOS transistor Q1 and the source of the second PMOS transistor Q2 are connected to the second end of the charging on-off module 10, the gate of the first PMOS transistor Q1 and the gate of the second PMOS transistor Q2 are connected to the third end of the charging on-off module 10, and the first resistor R1 is connected between the drain of the second PMOS transistor Q2 and the gate of the second PMOS transistor Q2.

[0049] In a specific embodiment of the present invention, Figure 5 As shown, the current sampling module 20 includes a second resistor R2, a first capacitor C1, a third resistor R3, a current sensor U1, a fourth resistor R4 and a first capacitor C2. The first end of the second resistor R2 is connected to the first end of the current sampling module 20, and the second end of the second resistor R2 is connected to the second end of the current sampling module 20. The first end of the second resistor R2 is connected to the first end of the first capacitor C1, the second end of the first capacitor C1 is connected to the first end of the third resistor R3, and the second end of the third resistor R3 is connected to the second end of the second resistor R2. The first end of the first capacitor C1 is connected to the SENSE+ terminal of the current sensor U1, and the second end of the first capacitor C1 is connected to the SENSE- terminal of the current sensor U1. The output end of the current sensor U1 is connected to the first end of the fourth resistor R4, and the second end of the fourth resistor R4 is grounded. The output end of the current sensor U1 is connected to the first end of the first capacitor C2, and the second end of the first capacitor C2 is grounded. The output end of the current sensor U1 is connected to the third end of the current sampling module 20. The current sensor U1 is used to collect the current passing through the second resistor R2 to determine the charging voltage.

[0050] In a specific embodiment of the present invention, Figure 5 As shown, the judgment module 30 includes a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, a third capacitor C3, a comparator U2A, a first NMOS transistor Q3, an eighth resistor R8, a fourth capacitor C4, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a fifth capacitor C5 and a twelfth resistor R12, a first end of the fifth resistor R5 is connected to the second end of the judgment module 30, a second end of the fifth resistor R5 is connected to the first end of the sixth resistor R6, a second end of the sixth resistor R6 is connected to the positive input end of the comparator U2A, a second end of the fifth resistor R5 is connected to the first end of the seventh resistor R7, a second end of the seventh resistor R7 is connected to the third capacitor The first end of C3 is connected, the second end of the seventh resistor R7 is grounded, the second end of the third capacitor C3 is connected to the second end of the sixth resistor R6, the ground end of the comparator U2A is grounded, the first end of the eighth resistor R8 is connected to the first wiring terminal J1, the second end of the eighth resistor R8 is connected to the power supply end of the comparator U2A, the second end of the eighth resistor R8 is connected to the first end of the fourth capacitor C4, the second end of the fourth capacitor is grounded, the negative input end of the comparator U2A is connected to the first end of the ninth resistor R9, the second end of the ninth resistor R9 is connected to the first end of the judgment module 30, the first end of the tenth resistor R10 is connected to the first wiring terminal J1, the second end of the tenth resistor R10 is connected to the first wiring terminal J1. The output terminal of the comparator U2A is connected to the first end of the eleventh resistor R11, the second end of the eleventh resistor R11 is grounded, the output terminal of the comparator U2A is connected to the gate of the first NMOS transistor Q3, the drain of the first NMOS transistor Q3 is grounded, the source of the first NMOS transistor Q3 is connected to the first end of the twelfth resistor R12, the second end of the twelfth resistor R12 is connected to the third end of the judgment module 30, the first end of the fifth capacitor C5 is connected to the first wiring terminal J1, and the second end of the fifth capacitor C5 is connected to the second end of the twelfth resistor R12; the positive input terminal of the comparator U2A is used to detect the reference voltage, compare The negative input terminal of the comparator U2A is used to detect the charging voltage passing through the ninth resistor R9. The comparator U2A is used to, when the voltage at the positive input terminal is greater than the voltage at the negative input terminal, determine that the charging current is less than a preset current threshold, output a high level, turn on the first NMOS transistor Q3, turn on the first PMOS transistor Q1 and the second PMOS transistor Q2, and conduct the charging circuit between the charging device and the battery; when the voltage at the positive input terminal is less than the voltage at the negative input terminal, determine that the charging current is greater than the preset current threshold, output a low level, turn off the first NMOS transistor Q3, turn off the first PMOS transistor Q1 and the second PMOS transistor Q2, and disconnect the charging circuit between the charging device and the battery.

[0051] Specifically, the second resistor R2 is a milliohm-level current sampling resistor that generates a voltage drop when current flows through it. The current sensor U1 linearly amplifies the voltage drop across the sampling resistor (the second resistor R2). The amplified voltage signal is fed to the negative input of the comparator U2A. The output of the current sensor U1 is connected to a sampling filter comprised of a second capacitor C2 and a fourth resistor R4 to stabilize the amplified charging voltage signal.

[0052] The voltage input from the first terminal J1 is stabilized by an RC filter formed by the eighth resistor R8 and the fourth capacitor C4, and then supplies power to the comparator U2A. The voltage input from the first terminal J1 is divided by the fifth resistor R5 and the seventh resistor R7, filtered by the sixth resistor R6 and the third capacitor C3, and then used as the overcurrent point reference (reference voltage) and transmitted to the positive input of the comparator U2A. The charging voltage output by the current sensor U1 is transmitted to the negative input of the comparator U2A through the ninth resistor R9. The ninth resistor R9 serves as a protective resistor for the negative input of the comparator U2A.

[0053] Comparator U2A compares the overcurrent level (reference voltage) input to the positive input with the charge level input to the negative input. When the overcurrent level input to the positive input is greater than the charge level input to the negative input, the charging current is determined to be less than a preset current threshold. When the overcurrent level input to the positive input is less than the charge level input to the negative input, the charging current is determined to be greater than a preset current threshold.

[0054] In the embodiment of the present invention, the output of the comparator U2A is open drain.

[0055] Specifically, when the overcurrent level input to the positive input of comparator U2A is greater than the charging level input to the negative input, comparator U2A outputs a high level. This high level output can turn on the first NMOS transistor Q3. In this embodiment of the utility model, the high level output by comparator U2A is a cutoff level, where the cutoff level is the voltage divided by the tenth resistor R10 and the eleventh resistor R11 at the first terminal J1. The tenth resistor R10 and the eleventh resistor R11 control the cutoff level between 5 and 20V. When the first NMOS transistor Q3 turns on, pins 2 (drain) and 3 (source) of the first NMOS transistor Q3 are turned on, creating a voltage difference between the gate and source of the first PMOS transistor Q1 and the second PMOS transistor Q2, turning them on simultaneously. Current flows through the first PMOS transistor Q1 and the second PMOS transistor Q2, through the sampling resistor R9, and reaches the second terminal J2 for output, charging the battery.

[0056] Specifically, when the overcurrent level input to the positive input of comparator U2A is less than the charge level input to the negative input, the output of comparator U2A is low, connecting to the ground line, the output level is 0V, and the first NMOS transistor Q3 is turned off. When the first NMOS transistor Q3 is turned off, the connection between pin 2 (drain) and pin 3 (source) of the first NMOS transistor Q3 is disconnected, and there is no voltage difference between the gate and source of the first PMOS transistor Q1 and the second PMOS transistor Q2, entering the off state.

[0057] When the battery charging current is less than the preset current threshold, pin 1 (output) of comparator U2A continuously outputs a high level, turning on the first NMOS transistor Q3 to keep the parallel power PMOS transistors (first PMOS transistor Q1 and second PMOS transistor Q2) turned on. When the battery charging current is greater than the preset current threshold, pin 1 (output) of comparator U2A outputs a low level, turning off the first NMOS transistor Q3 and the parallel power PMOS transistors (first PMOS transistor Q1 and second PMOS transistor Q2). As the current decreases and the sampled current signal gradually becomes less than the preset current threshold, pin 1 (output) of comparator U2A changes to a high level output, turning on the first NMOS transistor Q3. When an overcurrent is detected, the first NMOS transistor Q3 is turned off, achieving pulse protection charging.

[0058] It should be noted that the grounding of the components in the embodiment of the present invention is achieved by grounding. Specifically, the grounding point can be directly connected to the metal shell and then connected to the vehicle frame through a wiring harness.

[0059] In a specific embodiment of the present invention, the first NMOS transistor Q3 continuously carries a current of 20A and a peak current of 100A.

[0060] The first PMOS transistor Q1 and the second PMOS transistor Q2 of the present embodiment are P-channel power MOSFETs. The first NMOS transistor Q3 of the present embodiment is an N-channel signal-level MOSFET with a continuous current of 20A and a peak current of 100A.

[0061] The first terminal J1 and the second terminal J2 of the embodiment of the utility model are terminals that can pass a current of up to 175 A. The first terminal J1 can be connected to a high-voltage isolated DC / DC output, and the second terminal J2 can be connected to the positive terminal of the battery.

[0062] In one embodiment of the present invention, the preset current threshold sets a 20A current limiting parameter, wherein, Figure 6 The simulation waveforms of different charging currents are shown, and are close to the test results of the actual circuit.

[0063] In a specific embodiment of the present invention, Figure 5As shown, the driving module is an NMOS driver U3, and the discharge on-off module includes a second NMOS transistor Q4, a third NMOS transistor Q5, and a fourth NMOS transistor Q6. The source of the second NMOS transistor Q4, the source of the third NMOS transistor Q5, and the source of the fourth NMOS transistor Q6 are connected to the first end of the discharge on-off module, the drain of the second NMOS transistor Q4, the drain of the third NMOS transistor Q5, and the drain of the fourth NMOS transistor Q6 are connected to the second end of the discharge on-off module, the CATHODE end of the NMOS driver U3 is connected to the first end of the driving module 50, the VCAP end of the NMOS driver U3 is connected to the second end of the driving module 50 through the sixth capacitor C6 and the EN end of the NMOS driver U3, and the source of the second NMOS transistor Q4, the source of the third NMOS transistor Q5, and the source of the fourth NMOS transistor Q6 are connected to the CATHODE end of the NMOS driver U3. The gates of the second NMOS transistor Q4, the third NMOS transistor Q5, and the fourth NMOS transistor Q6 are connected to the GATE terminal of the NMOS driver U3, the drains of the second NMOS transistor Q4, the third NMOS transistor Q5, and the fourth NMOS transistor Q6 are connected to the ANODE terminal of the NMOS driver U3, and the GND terminal of the NMOS driver U3 is grounded; the NMOS driver U3 is configured to, when detecting that the voltage at the CATHODE terminal is lower than the voltage at the ANODE terminal, turn on the second NMOS transistor Q4, the third NMOS transistor Q5, and the fourth NMOS transistor Q6 to conduct a discharge loop formed between the load and the battery; and, when detecting that the voltage at the CATHODE terminal is higher than the voltage at the ANODE terminal, turn off the second NMOS transistor Q4, the third NMOS transistor Q5, and the fourth NMOS transistor Q6 to disconnect the discharge loop formed between the load and the battery.

[0064] In the embodiment of the present invention, pin 6 (ANODE) ​​of the NMOS driver U3 serves as the power input for the NMOS driver U3. Pin 1 (VCAP) of the NMOS driver U3 serves as the output of a boost charge pump (relative to the ANODE terminal). A sixth capacitor C6, connected in series with pin 1 (VCAP), is used to store energy to stabilize the voltage within the NMOS driver U3. Pin 5 (GATE) of the NMOS driver U3 controls the gates of the second, third, and fourth NMOS transistors Q4, Q5, and Q6. By applying a voltage, the GATE terminal can turn the second, third, and fourth NMOS transistors Q4, Q5, and Q6 on or off, thereby controlling and regulating the current.

[0065] In the embodiment of the present invention, the NMOS driver U3 detects that the voltage at pin 4 (CATHODE) is the voltage at the first terminal J1, and detects that the voltage at pin 6 (ANODE) ​​is the voltage at the second terminal J2. The NMOS driver U3 in this embodiment of the present invention can internally boost the voltage and drive the parallel NMOS transistors (the second NMOS transistor Q4, the third NMOS transistor Q5, and the fourth NMOS transistor Q6) to turn on.

[0066] When the battery needs to be charged, the charging device operates normally. The voltage on the charging side is higher than the voltage on the battery side 200, and current flows from the first terminal J1 to the second terminal J2. Current enters through the first terminal J1, and the NMOS driver U3 detects that the voltage at pin 4 is higher than the voltage at pin 6. It then shuts down the parallel NMOS transistors (second NMOS transistor Q4, third NMOS transistor Q5, and fourth NMOS transistor Q6), leaving current only able to flow through the parallel PMOS transistors (first PMOS transistor Q1 and second PMOS transistor Q2).

[0067] When the charging device stops working, the battery outputs electrical energy, with current flowing from the second terminal J2 to the first terminal J1. At this point, the power PMOS transistors (first and second PMOS transistors Q1, Q2) and the power NMOS transistors (first, second, third, and fourth NMOS transistors Q3, Q4, Q5, and Q6) are all turned on. However, the parallel internal resistance of the NMOS transistors is much smaller than that of the parallel PMOS transistors. Current flows from the battery through J2, the parallel NMOS transistors (second, third, and fourth NMOS transistors Q4, Q5, and Q6), and the first terminal J1, supplying power to the load.

[0068] In a specific embodiment of the present invention, the continuous current carried by the second NMOS transistor Q4, the third NMOS transistor Q5 and the fourth NMOS transistor Q6 is 50A, and the peak current is 230A.

[0069] The second NMOS transistor Q4, the third NMOS transistor Q5 and the fourth NMOS transistor Q6 of the embodiment of the utility model are N-channel power MOSFETs, which are devices with a continuous current of 50A and a peak current of 230A.

[0070] In a specific embodiment of the present invention, the current sensor U1 can be a ZXCT1109QSA-7 current sensor, the comparator U2A can be an LM2903 comparator, and the NMOS driver U3 can be an LM74700 NMOS driver. The models and parameters of other components such as resistors and capacitors can be set according to actual needs.

[0071] It should be noted that the present invention does not limit the models and parameters of other components such as the current sensor U1 , the comparator U2A, the NMOS driver U3 , the resistors, and the capacitors.

[0072] In a specific embodiment of the present invention, the second terminal J2 is connected to the first end of the seventh capacitor C7, and the second end of the seventh capacitor C7 is grounded.

[0073] Specifically, the positive terminal of the battery is connected to the second terminal J2. In order to stabilize the voltage output by the battery when the battery is discharged, the second terminal J2 is connected to the ground through the seventh capacitor C7.

[0074] The power components in the protection circuit of the battery charging protection device of this embodiment utilize MOSFETs, which have very low internal resistance, resulting in minimal losses during charging and discharging. The circuit is simple and low-cost. The protection circuit is compact and can be directly mounted to the battery's positive terminal, saving space and wiring. It does not require a main control chip such as an MCU, and the charging pulse width can be adaptively adjusted based on the overcurrent level, simplifying development.

[0075] The battery charging protection device of the embodiment of the utility model is applicable to the 12V system of passenger cars and the 24V system of commercial vehicles.

[0076] The battery charging protection device of the present invention reduces the load of the DC-DC converter when the battery is normally charged, and at the same time, the battery generates less heat. When the battery is low on power, it can effectively suppress the equivalent current, avoid excessive current charging, and greatly extend the battery life.

[0077] The utility model provides a vehicle.

[0078] Figure 7 Schematic diagram of a vehicle according to an embodiment of the present invention. Figure 7 As shown, the vehicle includes a charging device 200, a battery 300 and the battery charging protection device 100 as described above. The charging device is connected to the positive electrode of the battery through the battery charging protection device 100, and there is no load between the battery charging protection device 100 and the battery.

[0079] When the battery of a vehicle is low on power, the vehicle of the embodiment of the present invention can effectively suppress the equivalent current, avoid excessive current charging, and greatly extend the service life of the battery.

[0080] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0081] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present invention.

[0082] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this utility model, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0083] In this utility model, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0084] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0085] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are illustrative and cannot be understood as limitations on the present invention. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A battery charging protection device, characterized in that: The device comprises: a first connecting terminal, a protection circuit and a second connecting terminal, The first terminal is used to connect to a charging device; The second terminal is used to be connected to the positive electrode of the battery, and there is no load between the second terminal and the battery; The protection circuit includes a charging on-off module, a current sampling module, and a judgment module. The first end of the charging on-off module is connected to the first wiring terminal, the second end of the charging on-off module is connected to the first end of the current sampling module, the second end of the current sampling module is connected to the second wiring terminal, the third end of the current sampling module is connected to the first end of the judgment module, the first wiring terminal is connected to the second end of the judgment module, and the third end of the charging on-off module is connected to the third end of the judgment module. The judgment module is configured to turn on the charging on-off module when it is determined that the charging current is less than a preset current threshold based on a reference voltage and the charging voltage collected by the current collection module, so that a charging circuit is formed between the charging device and the battery, and the charging device charges the battery.

2. The battery charging protection device according to claim 1, characterized in that: The charging on-off module includes a first PMOS transistor, a second PMOS transistor and a first resistor. The drain of the first PMOS transistor and the drain of the second PMOS transistor are connected to the first end of the charging on-off module, the source of the first PMOS transistor and the source of the second PMOS transistor are connected to the second end of the charging on-off module, the gate of the first PMOS transistor and the gate of the second PMOS transistor are connected to the third end of the charging on-off module, and the first resistor is connected between the drain of the second PMOS transistor and the gate of the second PMOS transistor.

3. The battery charging protection device according to claim 2, characterized in that: The current sampling module includes a second resistor, a first capacitor, a third resistor, a current sensor, a fourth resistor, and a second capacitor. The first end of the second resistor is connected to the first end of the current sampling module, the second end of the second resistor is connected to the second end of the current sampling module, the first end of the second resistor is connected to the first end of the first capacitor, the second end of the first capacitor is connected to the first end of the third resistor, and the second end of the third resistor is connected to the second end of the second resistor. The first end of the first capacitor is connected to the SENSE+ terminal of the current sensor, the second end of the first capacitor is connected to the SENSE- terminal of the current sensor, the output end of the current sensor is connected to the first end of the fourth resistor, the second end of the fourth resistor is grounded, the output end of the current sensor is connected to the first end of the second capacitor, the second end of the second capacitor is grounded, and the output end of the current sensor is connected to the third end of the current sampling module. The current sensor is used to collect current passing through the second resistor to determine the charging voltage.

4. The battery charging protection device according to claim 3, characterized in that: The judgment module includes a fifth resistor, a sixth resistor, a seventh resistor, a third capacitor, a comparator, a first NMOS transistor, an eighth resistor, a fourth capacitor, a ninth resistor, a tenth resistor, an eleventh resistor, a fifth capacitor and a twelfth resistor. The first end of the fifth resistor is connected to the second end of the judgment module, the second end of the fifth resistor is connected to the first end of the sixth resistor, the second end of the sixth resistor is connected to the positive input end of the comparator, the second end of the fifth resistor is connected to the first end of the seventh resistor, the second end of the seventh resistor is connected to the first end of the third capacitor, the second end of the seventh resistor is grounded, the second end of the third capacitor is connected to the second end of the sixth resistor, the ground end of the comparator is grounded, the first end of the eighth resistor is connected to the first wiring terminal, the second end of the eighth resistor is connected to the power supply end of the comparator, and the The second end is connected to the first end of the fourth capacitor, the second end of the fourth capacitor is grounded, the negative input end of the comparator is connected to the first end of the ninth resistor, the second end of the ninth resistor is connected to the first end of the judgment module, the first end of the tenth resistor is connected to the first wiring terminal, the second end of the tenth resistor is connected to the output end of the comparator, the output end of the comparator is connected to the first end of the eleventh resistor, the second end of the eleventh resistor is grounded, the output end of the comparator is connected to the gate of the first NMOS transistor, the drain of the first NMOS transistor is grounded, the source of the first NMOS transistor is connected to the first end of the twelfth resistor, the second end of the twelfth resistor is connected to the third end of the judgment module, the first end of the fifth capacitor is connected to the first wiring terminal, and the second end of the fifth capacitor is connected to the second end of the twelfth resistor; The positive input terminal of the comparator is used to detect the reference voltage, and the negative input terminal of the comparator is used to detect the charging voltage passing through the ninth resistor. The comparator is used to determine that the charging current is less than a preset current threshold when the voltage at the positive input terminal is greater than the voltage at the negative input terminal, output a high level, turn on the first NMOS tube, turn on the first PMOS tube and the second PMOS tube, and conduct the charging circuit between the charging device and the battery; when the voltage at the positive input terminal is less than the voltage at the negative input terminal, determine that the charging current is greater than the preset current threshold, output a low level, turn off the first NMOS tube, turn off the first PMOS tube and the second PMOS tube, and disconnect the charging circuit between the charging device and the battery.

5. The battery charging protection device according to claim 1, characterized in that: The first terminal is connected to the load, and the protection circuit includes a discharge on-off module and a drive module. The first end of the discharge on-off module is connected to the first terminal, and the second end of the discharge on-off module is connected to the second terminal. The first end of the drive module is connected to the first terminal, and the second end of the drive module is connected to the second terminal. The drive module is driven by the discharge on-off module. When the drive module detects that the voltage of the first terminal is lower than the voltage of the second terminal, it turns on the discharge on-off module, so that a discharge circuit is formed between the load and the battery, and the battery discharges to the load.

6. The battery charging protection device according to claim 5, characterized in that: The driving module is an NMOS driver, and the discharge on-off module includes a second NMOS tube, a third NMOS tube, and a fourth NMOS tube. The source of the second NMOS tube, the source of the third NMOS tube, and the source of the fourth NMOS tube are connected to the first end of the discharge on-off module, the drain of the second NMOS tube, the drain of the third NMOS tube, and the drain of the fourth NMOS tube are connected to the second end of the discharge on-off module, the CATHODE end of the NMOS driver is connected to the first end of the driving module, and the VCAP end of the NMOS driver is connected to the first end of the driving module through the sixth capacitor and the NMOS transistor. The EN terminal of the MOS driver is connected to the second terminal of the driving module, the source of the second NMOS transistor, the source of the third NMOS transistor, and the source of the fourth NMOS transistor are connected to the CATHODE terminal of the NMOS driver, the gate of the second NMOS transistor, the gate of the third NMOS transistor, and the gate of the fourth NMOS transistor are connected to the GATE terminal of the NMOS driver, the drain of the second NMOS transistor, the drain of the third NMOS transistor, and the drain of the fourth NMOS transistor are connected to the ANODE terminal of the NMOS driver, and the GND terminal of the NMOS driver is grounded; The NMOS driver is configured to, when detecting that the voltage at the CATHODE terminal is lower than the voltage at the ANODE terminal, turn on the second NMOS transistor, the third NMOS transistor, and the fourth NMOS transistor, thereby conducting a discharge circuit formed by the load and the battery; and, when detecting that the voltage at the CATHODE terminal is higher than the voltage at the ANODE terminal, turn off the second NMOS transistor, the third NMOS transistor, and the fourth NMOS transistor, thereby disconnecting the discharge circuit formed by the load and the battery.

7. The battery charging protection device according to claim 4 or 6, characterized in that: The second terminal is connected to a first end of a seventh capacitor, and a second end of the seventh capacitor is grounded.

8. The battery charging protection device according to claim 4, characterized in that: The first NMOS transistor continuously carries a current of 20A, with a peak current of 100A.

9. The battery charging protection device according to claim 6, characterized in that: The continuous current carried by the second NMOS transistor, the third NMOS transistor, and the fourth NMOS transistor is 50A, with a peak current of 230A.

10. A vehicle, characterized in that: The invention comprises a charging device, a battery and a battery charging protection device according to any one of claims 1 to 9, wherein the charging device is connected to the positive electrode of the battery through the battery charging protection device, and there is no load between the battery charging protection device and the battery.

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