Vehicle machine starting lithium battery protection circuit and protector applying same

Abstract

The utility model discloses an in-vehicle machine starting lithium battery protection circuit and a protector applying the same, and relates to the technical field of automobile lithium batteries, the in-vehicle machine starting lithium battery protection circuit comprises a charging management chip, a charging control switch tube and a shunt capacitor voltage division unit; the charging management chip is connected in parallel to the anode and cathode ends of the lithium battery; the charging management chip is connected with the charging control switch tube and the shunt capacitance voltage division unit in sequence; the charging control switch tube is connected with the charging management chip and outputs a lithium battery charging signal and a charging shutdown signal; and the shunt capacitance voltage division unit is connected in parallel with the charging start-stop control unit. The lithium battery protection circuit effectively improves the fault problem of intermittent flash outage caused when the lithium battery protection circuit is disconnected from charging.

Description

Technical Field

[0001] This application relates to the field of automotive lithium battery technology, and in particular to a vehicle start-up lithium battery protection circuit and a protector using the same. Background Technology

[0002] Modern cars are now using lithium-ion batteries instead of lead-acid batteries for their starting batteries. Due to inherent safety concerns, lithium-ion batteries cannot be overcharged, so a protection circuit is typically added. When the lithium-ion battery voltage becomes too high, overcharge protection is triggered, shutting off the charging circuit. However, for lithium-ion battery protection circuits that use a single positive and negative terminal for both charging and discharging, the battery voltage drops after the charging circuit is shut off because other electrical devices in the vehicle continue to use power. This causes the protection circuit to deactivate, allowing the lithium-ion battery to continue charging. Because it's a single-terminal protection circuit, discharging also stops when charging is disconnected, potentially causing sudden, intermittent power outages. Therefore, there is room for improvement. Utility Model Content

[0003] In order to effectively improve the fault problem of intermittent power failure caused by the lithium battery protection circuit when disconnecting charging, this application provides a vehicle start-up lithium battery protection circuit and a protector using the same.

[0004] Firstly, this application provides a vehicle startup lithium battery protection circuit, which adopts the following technical solution:

[0005] A vehicle-mounted start-up lithium battery protection circuit includes a charging management chip, a charging control switch, and a parallel capacitor voltage divider unit. The charging management chip is connected in parallel to the positive and negative terminals of the lithium battery. The charging management chip is sequentially connected to the charging control switch and the parallel capacitor voltage divider unit. The charging control switch is connected to the charging management chip and outputs a lithium battery charging signal and a charging stop signal. The parallel capacitor voltage divider unit is connected in parallel to the charging start-stop control unit.

[0006] By adopting the above technical solution, the charging management chip is used to control the charging process of the automotive lithium battery. It can automatically adjust the charging mode according to the battery status and stop charging when the battery is fully charged. At the same time, in order to effectively improve the fault problem of intermittent power failure caused by the lithium battery protection circuit when the charging is disconnected, this application connects a parallel capacitor voltage divider unit (e.g., a parallel supercapacitor to act as a voltage divider) in parallel with the charging control switch (such as a charging MOSFET) in the lithium battery protection circuit. When the lithium battery charging voltage is too high (the charging voltage of the vehicle's alternator is usually 15-16V; the safe voltage of the lithium battery is 14.6V), that is, when the alternator voltage of the vehicle's alternator is too high to 16V and the lithium battery is protected at 14.6V, 1.4V of the charging circuit is shared by the parallel capacitor voltage divider unit, so that the entire charging circuit of the lithium battery is still in a conducting state. The vehicle's alternator will not alarm due to overvoltage, thereby effectively avoiding vehicle fault alarms and facilitating the charging protection of the vehicle's lithium battery.

[0007] Preferably, the system further includes a main control chip and a low-voltage linear regulator. The data transmission control terminal of the main control chip is connected to the charging management chip, the power supply terminal of the main control chip is connected to the low-voltage linear regulator, the input terminal of the low-voltage linear regulator is connected to the positive terminal of the lithium battery, and the output terminal of the low-voltage linear regulator is connected to the main control chip and the charging management chip in sequence.

[0008] By adopting the above technical solution, the data transmission control terminal of the main control chip is connected to the charging management chip, which can realize precise monitoring and adjustment of the charging process; the low-voltage linear regulator is used to provide a stable operating voltage for the main control chip when the lithium battery voltage fluctuates.

[0009] Preferably, the charging management chip is model HT7533, and the charging control switch is a charging MOSFET.

[0010] By adopting the above technical solution, the HT7533 chip has advantages such as high efficiency and low quiescent current, which is beneficial to improving the charging efficiency of lithium batteries.

[0011] Preferably, the parallel capacitor voltage divider unit includes a supercapacitor, which is connected in parallel with the charging MOSFET.

[0012] By adopting the above technical solutions, supercapacitors have very high charge and discharge rates and can rapidly absorb or release energy.

[0013] Preferably, the supercapacitor has a capacitance of 3 farads.

[0014] By adopting the above technical solutions, low-capacity supercapacitors can provide energy buffering while effectively reducing costs and design complexity.

[0015] Preferably, the main control chip includes SC8F072AD614SP or SC8P1715E.

[0016] By adopting the above technical solutions, the SC8F072AD614SP or SC8P1715E chips have lower operating power consumption and stronger data interaction and processing capabilities.

[0017] Preferably, the charging management chip is also connected to a multi-cell battery balancing interface and several protection switches. The gate of the protection switch is connected to the power supply pin of the charging management chip, the drain of the protection switch is connected to the multi-cell battery balancing interface, the source of the protection switch is connected to the drain of another adjacent protection switch, and a capacitor is connected to the gate of the two adjacent protection switches.

[0018] By adopting the above technical solution, since automotive lithium batteries are often designed with multiple cells connected in series or parallel in practical applications, in order to improve the control effect and accuracy of lithium batteries, this application connects the charging management chip to the multi-cell equalization interface and uses protection switching transistors to control the current path. This ensures that each cell can reach its optimal state during charging, avoids the problem of overcharging or undercharging some cells, and extends the overall lifespan of the battery pack. At the same time, a capacitor is connected between the gates of two adjacent protection switching transistors, which helps to smooth the voltage fluctuations of the lithium battery during charging and use.

[0019] Preferably, the charging management chip is also connected to a rectifier.

[0020] By adopting the above technical solution, the rectifier can assist the charging management chip in adapting to different external power input conditions, thereby enhancing the adaptability of lithium batteries.

[0021] Secondly, the protector provided in this application adopts the following technical solution:

[0022] A protector includes a circuit board carrying a vehicle startup lithium battery protection circuit as described above.

[0023] In summary, this application includes at least one of the following beneficial technical effects:

[0024] 1. Connect a parallel capacitor voltage divider unit (e.g., a parallel supercapacitor to act as a voltage divider) in parallel with the charging control switch (such as a charging MOSFET) in the lithium battery protection circuit. This allows the lithium battery to be charged at too high a voltage (typically, the alternator charging voltage in a vehicle is 15-16V; the safe voltage of a lithium battery is 14.6V). Specifically, when the alternator voltage in the vehicle is too high (16V) and the lithium battery is under 14.6V protection, 1.4V of the charging circuit is distributed to the parallel capacitor voltage divider unit. This ensures that the entire charging circuit of the lithium battery remains conductive, preventing the vehicle from triggering an alarm due to overvoltage. This effectively avoids vehicle malfunction alarms and is beneficial for protecting the vehicle's lithium battery during charging.

[0025] 2. The functionality of the vehicle's start-up lithium battery protection circuit has been enhanced in various aspects, including improved transient response capability and enhanced system stability. Attached Figure Description

[0026] Figure 1 This is a circuit diagram of a charging management chip, a charging control switch, and a parallel capacitor voltage divider unit in a vehicle startup lithium battery protection circuit according to an embodiment of this application.

[0027] Figure 2 This is a circuit diagram of the main control chip and low-voltage linear regulator in a vehicle startup lithium battery protection circuit according to an embodiment of this application.

[0028] Explanation of reference numerals in the attached figures:

[0029] 1. Charging control switch; 2. Parallel capacitor voltage divider unit; 3. Rectifier. Detailed Implementation

[0030] The following is in conjunction with the appendix Figure 1-2 This application will be described in further detail.

[0031] Example 1

[0032] This application discloses a lithium battery protection circuit for vehicle startup. (Refer to...) Figure 1 and Figure 2 The vehicle startup lithium battery protection circuit includes a main control chip U1, a charging management chip U2, a charging control switch 1, a parallel capacitor voltage divider unit 2, and a low-voltage linear regulator U3.

[0033] Reference Figure 1 and Figure 2 ,by Figure 1 and Figure 2 Taking the circuit diagram shown as an example, the charging management chip U2 is connected in parallel across the positive and negative terminals of the lithium battery (the lithium battery is in...). Figure 1(Not shown in the image). The data transmission control terminal of the main control chip U1 is connected to the charging management chip U2. The power supply terminal of the main control chip U1 is connected to the low-voltage linear regulator U3. The input terminal of the low-voltage linear regulator U3 is connected to the positive terminal of the lithium battery. The output terminal of the low-voltage linear regulator U3 is connected to the main control chip U1 and the charging management chip U2 in sequence. The model of the main control chip U1 includes SC8F072AD614SP or SC8P1715E. The model of the charging management chip U2 is HT7533. The charging management chip U2 is connected to the charging control switch 1 and the parallel capacitor voltage divider unit 2 in sequence. The charging control switch 1 is connected to the charging management chip U2 and outputs a lithium battery charging signal and a charging stop signal. The lithium battery charging signal is used to control the lithium battery charging circuit to conduct, charging the lithium battery. The charging stop signal is used to control the lithium battery charging circuit to cut off, stopping the charging of the lithium battery. The parallel capacitor voltage divider unit 2 is connected in parallel with the charging start / stop control unit.

[0034] Reference Figure 1 The parallel capacitor voltage divider unit 2 includes a supercapacitor, and the charging control switch 1 is a charging MOSFET. Figure 1 The MOSFET Q7 is located in the middle; the supercapacitor is connected in parallel with the charging MOSFET, and the supercapacitor has a capacitance of 3 farads; the charging management chip U2 is also connected to a multi-cell balancing interface J5 and several protection switches. The gate of the protection switch is connected to the power supply pins (VC0, VC1, VC2, VC3, VC4 pins) of the charging management chip U2, the drain of the protection switch is connected to the multi-cell balancing interface J5, and the source of the protection switch is connected to the drain of another adjacent protection switch. A capacitor is connected to the gate of each adjacent protection switch. In this embodiment, four protection switches are provided, such as... Figure 1 The MOS transistors are connected to the VC0, VC1, VC2, VC3, and VC4 pins of the charging management chip U2.

[0035] Reference Figure 2 The charging management chip U2 is also connected to a rectifier 3. By connecting to the rectifier 3, the vehicle's starting lithium battery protection circuit can adapt to different power input conditions, such as household AC power and vehicle DC power.

[0036] The implementation principle of the vehicle start-up lithium battery protection circuit in this application embodiment is as follows: a 3-farad supercapacitor is connected in parallel with the charging MOS transistor in the lithium battery protection circuit to act as a voltage divider. When the lithium battery charging voltage is too high, for example, when the generator voltage of the vehicle is high at 16V and the lithium battery voltage is 14.6V, 1.4V of the charging circuit is distributed to the parallel capacitor voltage divider unit 2, so that the entire charging circuit of the lithium battery is still in a conducting state, and the vehicle will not alarm due to overvoltage, thereby effectively avoiding vehicle fault alarms and facilitating the charging protection of the vehicle lithium battery. Furthermore, unlike the existing technology that connects a protection circuit consisting of multiple 20-farad supercapacitors in series in parallel with the positive and negative terminals of the lithium battery, the vehicle start-up lithium battery protection circuit of this application also helps to save product size space and reduce production costs in actual production.

[0037] Example 2

[0038] This application also discloses a protector.

[0039] This application discloses a protector, which includes a circuit board carrying a vehicle startup lithium battery protection circuit.

[0040] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A vehicle machine starting lithium battery protection circuit, characterized in that, The charging management chip, the charging control switch tube and the parallel capacitor voltage division unit are included; the charging management chip is connected in parallel at the positive and negative poles of the lithium battery; the charging management chip is connected with the charging control switch tube and the parallel capacitor voltage division unit in sequence; the charging control switch tube is connected with the charging management chip and outputs the lithium battery charging signal and the charging start-stop signal; the parallel capacitor voltage division unit is connected with the charging start-stop control unit in parallel.

2. The protection circuit for starting a lithium battery of a car machine according to claim 1, characterized in that, The master control chip and the low-voltage linear voltage stabilizer are further included, the data transmission control end of the master control chip is connected with the charging management chip, the power supply end of the master control chip is connected with the low-voltage linear voltage stabilizer, the input end of the low-voltage linear voltage stabilizer is connected with the positive pole of the lithium battery, and the output end of the low-voltage linear voltage stabilizer is connected with the master control chip and the charging management chip in sequence.

3. The protection circuit for starting a lithium battery of a car according to claim 1, wherein The model of the charging management chip is HT7533, and the charging control switch tube is a charging MOS tube.

4. The protection circuit for starting a lithium battery of a car according to claim 3, wherein The parallel capacitor voltage division unit includes a super capacitor, and the super capacitor is connected with the charging MOS tube in parallel.

5. The protection circuit for starting a lithium battery of a car according to claim 4, wherein The capacity of the super capacitor is 3 farad.

6. The protection circuit for starting a lithium battery of a car according to claim 1, wherein The model of the master control chip includes SC8F072AD614SP or SC8P1715E.

7. The protection circuit for starting a lithium battery of a car according to claim 1, wherein The charging management chip is further connected with a multi-battery equalization interface and a plurality of protection switch tubes, the gate of the protection switch tube is connected with the power supply pin of the charging management chip, the drain of the protection switch tube is connected with the multi-battery equalization interface, the source of the protection switch tube is connected with the drain of another adjacent protection switch tube, and the gates of the adjacent two protection switch tubes are connected with a capacitor.

8. The protection circuit for starting a lithium battery of a car according to claim 1, wherein The charging management chip is further connected with a rectifier.

9. A protector comprising a circuit board, characterized in that The circuit board bears a vehicle machine starting lithium battery protection circuit as claimed in any one of claims 1-8.

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