Lithium battery protection circuit with low-temperature heating function

Abstract

The utility model discloses a lithium battery protection circuit with low temperature heating, which comprises a charging and discharging protection circuit and a lithium battery heating circuit, the positive and negative electrodes B + and B-of a lithium battery are connected by positive and negative charging terminals P + and P-through a charging and discharging MOS tube, and the charging and discharging protection circuit collects the voltage of each single body of the lithium battery and is connected with and controls the work of the charging and discharging MOS tube. Charging over-voltage protection and discharging under-voltage protection are realized; the lithium battery heating circuit comprises a temperature acquisition module, a differential comparator, a heating sheet control module and a heating sheet which are connected in sequence; the temperature acquisition module acquires temperature information in the charging and discharging process of the lithium battery, and the heating piece control module controls the heating piece to heat the lithium battery. According to the lithium battery protection circuit with the low-temperature heating function, in the charging and discharging process of the lithium battery, charging overvoltage protection and discharging undervoltage protection are achieved, and meanwhile the lithium battery can be heated when the temperature of the lithium battery is below 0 DEG C so that the lithium battery can work at the normal temperature.

Description

Technical Field

[0001] The utility model relates to the field of lithium battery protection, and particularly relates to a lithium battery protection circuit with low-temperature heating. Background Art

[0002] Lithium batteries have the advantages of relatively high energy, long service life, high rated voltage, high power tolerance, very low self-discharge rate, light weight, and strong adaptability to high and low temperatures, but they have the disadvantages of poor safety and the need for a protection circuit to prevent overcharging, over-discharging, over-current, short-circuit, over-temperature protection, etc.

[0003] Traditional lithium battery protection circuits have protection functions for overvoltage, undervoltage, charge and discharge current, etc. of lithium batteries, but lack an efficient and simple solution to keep lithium batteries at normal temperature in a low-temperature environment. Summary of the Utility Model

[0004] The purpose of the utility model is to provide a lithium battery protection circuit with low-temperature heating, which can heat the lithium battery below 0°C so that it works at a normal temperature.

[0005] The technical solution of the utility model is as follows:

[0006] The lithium battery protection circuit with low-temperature heating includes a charge and discharge protection circuit and a lithium battery heating circuit. The positive and negative electrodes B+ and B- of the lithium battery are connected by positive and negative charging terminals P+ and P- through charge and discharge MOS transistors. The charge and discharge protection circuit collects the voltages of each monomer of the lithium battery and connects to control the operation of the charge and discharge MOS transistors to achieve overvoltage protection during charging and undervoltage protection during discharging.

[0007] The lithium battery heating circuit includes a temperature acquisition module, a differential comparator, a heating sheet control module, and a heating sheet connected in sequence. The temperature acquisition module collects the temperature information during the charge and discharge process of the lithium battery. When the temperature of the lithium battery is less than or equal to 0°C, the heating sheet control module controls the heating sheet to heat the lithium battery.

[0008] Preferably, the temperature acquisition module includes a thermistor NTC. One end of the thermistor NTC is grounded, and the other end is connected to the positive charging terminal P+ through a resistor R12.

[0009] Preferably, the differential comparator uses LM331AU2. The +IN input pin of the differential comparator is connected to the thermistor NTC through a resistor R12. The –IN input pin of the differential comparator is connected to a reference voltage through a resistor R12. The OUT output pin of the differential comparator is connected to the heating sheet control module, and the OUT output pin is also connected to the positive charging terminal P+ through a resistor R25.

[0010] Preferably, the heating sheet control module includes transistors Q5 and Q6; the OUT output pin of the differential comparator is connected to the base of transistor Q5 through resistor R17. The emitter of transistor Q5 is grounded, and the collector is connected to the positive charging terminal P+ through resistor R19. A resistor R18 is connected between the emitter and the base of transistor Q5. The collector of transistor Q5 is connected to the base of transistor Q6 through resistor R20; the collector of transistor Q6 is grounded through resistor R22, and the emitter is connected to the positive charging terminal P+ through resistor R22. A zener diode D4 is connected between the emitter and the base.

[0011] Preferably, the heating sheet includes positive and negative terminals CH+ and CH-. The positive terminal CH+ is connected to the positive charging terminal P+. The negative terminal CH- is connected to the negative charging terminal P- through MOS transistor Q7. The gate of MOS transistor Q7 is connected to the collector of transistor Q6.

[0012] Preferably, the collector of transistor Q6 is also connected to the negative charging terminal P- through a parallel combination of resistor R23 and zener diode D3.

[0013] Preferably, the reference voltage is provided by resistors R14 and R15. Resistors R14 and R15 are connected in series between the positive and negative charging terminals P+ and P- in sequence. The connection point between resistors R14 and R15 provides the reference voltage.

[0014] Preferably, the charge and discharge protection circuit uses a three-cell lithium battery protection chip HTL6033AAAFYT14 / R6.

[0015] The advantages of the present invention are:

[0016] The lithium battery protection circuit with low-temperature heating provided by the present invention can heat the lithium battery when the temperature of the lithium battery is below 0°C while achieving overcharge protection during charging and under-discharge protection during discharging, enabling it to operate at a normal temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The following further describes the present invention in conjunction with the drawings and embodiments:

[0018] Figure 1 It is a schematic diagram of the lithium battery protection circuit with low-temperature heating of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] As Figure 1 shown, the lithium battery protection circuit with low-temperature heating of the present invention includes a charge and discharge protection circuit and a lithium battery heating circuit. The positive and negative electrodes B+ and B- of the lithium battery are connected by the positive and negative charging terminals P+ and P- through charge and discharge MOS transistors Q1 - Q4.

[0020] The charge and discharge protection circuit uses a three - cell lithium battery protection chip HTL6033AAAFYT14 / R6. The three - cell lithium battery protection chip collects the voltages of each single cell of the lithium battery and connects to control the operation of the charge and discharge MOS transistors Q1 - Q4 to achieve over - voltage protection during charging and under - voltage protection during discharging.

[0021] The lithium battery heating circuit includes a temperature acquisition module, a differential comparator, a heating sheet control module, and a heating sheet connected in sequence. The temperature acquisition module collects the temperature information during the charge and discharge process of the lithium battery. When the lithium battery temperature is less than or equal to 0°C, the heating sheet control module controls the heating sheet to heat the lithium battery.

[0022] The temperature acquisition module includes a thermistor NTC. One end of the thermistor NTC is grounded, and the other end is connected to the positive charging terminal P+ through a resistor R12.

[0023] The differential comparator uses LM331AU2. The +IN input pin of the differential comparator is connected to the thermistor NTC through a resistor R12. The –IN input pin of the differential comparator is connected to the reference voltage through a resistor R12. The OUT output pin of the differential comparator is connected to the heating sheet control module, and the OUT output pin is also connected to the positive charging terminal P+ through a resistor R25. The reference voltage is provided by resistors R14 and R15. The resistors R14 and R15 are connected in series between the positive and negative charging terminals P+ and P - in sequence, and the connection point between the resistors R14 and R15 provides the reference voltage.

[0024] The heating sheet control module includes transistors Q5 and Q6. The OUT output pin of the differential comparator is connected to the base of transistor Q5 through a resistor R17. The emitter of transistor Q5 is grounded, and the collector is connected to the positive charging terminal P+ through a resistor R19. A resistor R18 is connected between the emitter and the base of transistor Q5. The collector of transistor Q5 is connected to the base of transistor Q6 through a resistor R20. The collector of transistor Q6 is grounded through a resistor R22, and the emitter is connected to the positive charging terminal P+ through a resistor R22. A zener diode D4 is connected between the emitter and the base.

[0025] The heating sheet includes positive and negative terminals CH+ and CH-. The positive terminal CH+ is connected to the positive charging terminal P+. The negative terminal CH - is connected to the negative charging terminal P - through a MOS transistor Q7. The gate of the MOS transistor Q7 is connected to the collector of transistor Q6. The collector of transistor Q6 is also connected to the negative charging terminal P - through a parallel combination of a resistor R23 and a zener diode D3. During the charge and discharge process, when the lithium battery temperature is less than or equal to 0°C, the heating circuit is turned on, and the heating sheet heats the lithium battery.

[0026] The above embodiments are only for illustrating the technical concept and features of the present utility model, and the purpose is to enable those skilled in the art to understand the content of the present utility model and implement it accordingly, and it should not be used to limit the protection scope of the present utility model. All modifications made according to the spirit of the main technical solution of the present utility model should be covered within the protection scope of the present utility model.

Claims

1. A lithium battery protection circuit with low temperature heating, characterized in that: It includes a charge and discharge protection circuit and a lithium battery heating circuit. The positive and negative electrodes B+ and B- of the lithium battery are connected by the positive and negative charging terminals P+ and P- through a charge and discharge MOS tube. The charge and discharge protection circuit collects the voltage of each monomer of the lithium battery and connects to control the operation of the charge and discharge MOS tube to achieve charge overvoltage protection and discharge undervoltage protection; The lithium battery heating circuit includes a temperature acquisition module, a differential comparator, a heating plate control module and a heating plate connected in sequence; the temperature acquisition module collects temperature information during the charging and discharging process of the lithium battery, and when the temperature of the lithium battery is less than or equal to 0°C, the heating plate control module controls the heating plate to heat the lithium battery.

2. The lithium battery protection circuit with low temperature heating according to claim 1, characterized in that: The temperature acquisition module includes a thermistor NTC, one end of the thermistor NTC is grounded, and the other end is connected to the positive charging terminal P+ through a resistor R12.

3. The lithium battery protection circuit with low temperature heating according to claim 2, characterized in that: The differential comparator adopts LM331AU2, the +IN input pin of the differential comparator is connected to the thermistor NTC through a resistor R12, the –IN input pin of the differential comparator is connected to the reference voltage through a resistor R12, the OUT output pin of the differential comparator is connected to the heater control module, and the OUT output pin is also connected to the positive charging terminal P+ through a resistor R25.

4. The lithium battery protection circuit with low temperature heating according to claim 3, characterized in that: The heating plate control module includes transistors Q5 and Q6; the OUT output pin of the differential comparator is connected to the base of the transistor Q5 through a resistor R17, the emitter of the transistor Q5 is grounded, the collector is connected to the positive charging terminal P+ through a resistor R19, the emitter and base of the transistor Q5 are connected through a resistor R18, and the collector of the transistor Q5 is connected to the base of the transistor Q6 through a resistor R20; the collector of the transistor Q6 is grounded through a resistor R22, the emitter is connected to the positive charging terminal P+ through a resistor R22, and the emitter and base are connected through a voltage regulator tube D4.

5. The lithium battery protection circuit with low temperature heating according to claim 4, characterized in that: The heating plate includes positive and negative terminals CH+ and CH-, the positive terminal CH+ is connected to the positive charging terminal P+, the negative terminal CH- is connected to the negative charging terminal P- through the MOS tube Q7, and the gate of the MOS tube Q7 is connected to the collector of the transistor Q6.

6. The lithium battery protection circuit with low temperature heating according to claim 5, characterized in that: The collector of the transistor Q6 is also connected to the negative charging terminal P- through a resistor R23 and a voltage regulator D3 connected in parallel.

7. The lithium battery protection circuit with low temperature heating according to claim 3, characterized in that: The reference voltage is provided by resistors R14 and R15, which are sequentially connected in series between the positive and negative charging terminals P+ and P-, and the connection point between the resistors R14 and R15 provides the reference voltage.

8. The lithium battery protection circuit with low temperature heating according to claim 1, characterized in that: The charge and discharge protection circuit adopts three-cell lithium battery protection chip HTL6033AAAFYT14 / R6.

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