Solar low temperature heating circuitry

Abstract

The application discloses a kind of solar low-temperature heating circuit system, including low-temperature heating circuit system ontology, power module is equipped on low-temperature heating circuit system ontology, environmental detection circuit, driving switch, battery charge-discharge switch, power module is powered by lithium battery, respectively for internal temperature detection unit and external temperature detection unit provide power supply, driving switch simultaneously accepts the signal of external temperature detection and internal temperature, resistance R1 is heating resistance film, usually lithium battery is wrapped in the inside of resistance film, respectively connected to the anode of lithium battery and the input of driving switch, the effect of lithium battery protection plate, first cut off lithium battery charge-discharge switch, make the negative pole of solar panel and the negative pole of lithium battery disconnect, while environmental detection circuit detects external signal, this solar heating circuit can meet the heating demand of lithium battery under low-temperature condition, but does not consume the energy of lithium battery.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of lithium batteries, in particular to a solar low-temperature heating circuit system. BACKGROUND

[0002] With the wider use of lithium batteries, the characteristics of the reduced activity of the lithium batteries under low temperature are paid more and more attention, and how to keep the lithium batteries active under low temperature becomes the focus of research, and the only way to keep the lithium batteries active under low temperature is to improve the temperature of the lithium batteries, if the lithium batteries are used to heat at this time, the activity of the lithium batteries is reduced, the working state is not ideal, and the electric quantity of the lithium batteries is consumed, the scheme is relatively simple, but has defects, therefore, an improved technology is urgently needed to solve the problem in the prior art. SUMMARY

[0003] The application aims to provide a solar low-temperature heating circuit system which is provided with a power module, an environment detection circuit, a driving switch and a battery charging and discharging switch on a low-temperature heating circuit system body, the power module is powered by a lithium battery, and provides power supply for an internal temperature detection unit and an external temperature detection unit respectively, the driving switch simultaneously receives signals of the external temperature detection and the internal temperature, the resistance R1 is a heating resistance film, the lithium battery is usually wrapped in the internal resistance film, and is connected to a positive electrode of the lithium battery and an input of the driving switch respectively, the lithium battery protection plate has the following effects: firstly, the charging and discharging switch of the lithium battery is cut off, the negative electrode of the solar panel is disconnected with the negative electrode of the lithium battery, and the environment detection circuit detects external signals, so that the heating demand of the lithium battery under low temperature conditions can be met, and the energy of the lithium battery is not consumed, thereby solving the problems in the background technology.

[0004] To achieve the above-mentioned purpose, the application provides the following technical scheme: a solar low-temperature heating circuit system, comprising a low-temperature heating circuit system body, wherein the low-temperature heating circuit system body is provided with a power module, an environment detection circuit, a driving switch and a battery charging and discharging switch, the power module is connected with a positive electrode of a lithium battery and a negative electrode of the lithium battery respectively, one connection end of the power module is connected with one end of the environment detection circuit, the other end of the environment detection circuit is connected with one end of the driving switch, one connection end of the driving switch is grounded, the other end of the driving switch is connected with one end of a resistance R1, the other end of the resistance R1 is connected with a positive electrode of a solar panel, and one end of the battery charging and discharging switch is connected with a negative electrode of the solar panel.

[0005] Preferably, the power module comprises a capacitor C35, a capacitor C36, a resistance R68, a resistance R71, a voltage stabilizing tube D15, an NPN triode Q25 and a diode D11.

[0006] The NPN transistor Q25, voltage stabilizing tube D15, resistor R71 constitute a voltage stabilizing circuit, resistor R71 connects the base and collector of NPN transistor Q25, the negative electrode of voltage stabilizing diode D15 is connected with the base of NPN transistor Q25, the positive electrode is grounded, the emitter of NPN transistor Q25 is connected with the positive electrode of diode D11, resistor R68 constitutes a current limiting circuit, connecting the positive electrode of lithium battery and the collector of transistor Q25, diode D11 constitutes a reverse prevention circuit, the positive electrode is connected with the emitter of NPN transistor Q25, and the negative electrode is connected with the output power supply;

[0007] The capacitor C35 and capacitor C36 constitute a filter circuit, the capacitor C35 is connected with the positive and negative electrodes of lithium battery, and the capacitor C36 is connected with the positive and negative electrodes of power supply output.

[0008] Preferably, the environment detection circuit comprises 1M resistor R83, 200K resistor R89, 1M resistor R88, 1K resistor R102, thermistor NTC2, 1M resistor R79, 5.1M resistor R80, comparator U5A and 100K resistor R87.

[0009] The 1M resistor R83 and 200K resistor R89 constitute a voltage dividing circuit, the 1M resistor R83 and 200K resistor R89 are connected in series between the power supply and the ground in sequence, the middle of the 1M resistor R83 and 200K resistor R89 is connected to the 3 pin of U5A, the 1M resistor R88, 1K resistor R102 and thermistor NTC2 constitute an environment temperature detection circuit, R88, R102 and thermistor NTC2 are connected in series between the power supply and the ground in sequence, the middle of the 1M resistor R88 and 1K resistor R102 is connected to the 2 pin of comparator U5A, the 5 pin of comparator U5A is connected to the power supply, the 2 pin of comparator U5A is grounded, and R87 connects the 1 pin of comparator U5A and the 1 pin of CJ2301P-MOS transistor Q31.

[0010] Preferably, the solar panel detection circuit connected with the solar panel on the low-temperature heating circuit system body comprises 1M resistor R67, NPN transistor Q24, diode D13, 3M resistor R64, 1M resistor R57, PNP transistor Q20 and diode D12.

[0011] The 1M resistor R67, NPN transistor Q24, diode D13 constitute a solar panel detection circuit, 1M resistor R67 connects the negative of lithium battery and the base of NPN transistor Q25, the positive of diode D13 connects the emitter of NPN transistor Q25, the negative of diode D13 connects the negative of solar panel, the 3M resistor R64, 1M resistor R57, PNP transistor Q20, diode D12 constitute a switch circuit, 3M resistor R64 connects the collector of NPN transistor Q24 and the base of PNP transistor Q20, 1M resistor R57 connects the base and collector of PNP transistor Q20, the emitter of PNP transistor Q20 connects the positive of diode D12.

[0012] Preferably, the driving switch includes 100K resistor R82, 100K resistor R87, CJ2301P-MOS tube Q31, 470K resistor R97, 470 resistor R108, NPN transistor Q35, 1M resistor R86, 470K resistor R78, PNP transistor Q29, 200K resistor R85, N-MOS tube Q19, 470K resistor R98.

[0013] The 100K resistor R82 connects the gate and drain of CJ2301P-MOS tube Q31, the gate of CJ2301P-MOS tube Q31 connects 100K resistor R87, the drain of CJ2301P-MOS tube Q31 connects the negative of D12, 470K resistor R97 connects the source of CJ2301P-MOS tube Q31 and the base of NPN transistor Q35, 470 resistor R108 connects the base and emitter of NPN transistor Q35, 1M resistor R86 connects the collector of NPN transistor Q35 and the base of PNP transistor Q29, 470K resistor R78 connects the base and collector of PNP transistor Q29, 200K resistor R85 connects the emitter of PNP transistor Q29 and the gate of N-MOS tube Q19, 470K resistor R98 connects the gate and source of N-MOS tube Q19, the source of N-MOS tube Q19 connects the negative of solar panel, the drain of N-MOS tube Q19 connects one end of heating film resistor, the other end of heating resistor connects the positive of solar panel, the gate of N-MOS tube Q19 connects GND2 end.

[0014] Preferably, a working method of a solar low-temperature heating circuit system includes the following steps:

[0015] Step one, in the initial state, the lithium battery charge and discharge switch is in the on state, the solar panel and the lithium battery are in the common positive and common negative state, the gate of CJ2301P-MOS tube Q31 is 4.5V, because of the cutoff effect of D12, the drain of CJ2301P-MOS tube Q31 is also 4.5V, Q31 is in the closed state, and the subsequent driving switch circuit is also in the closed state, and the system is not heated;

[0016] Step two, in the low temperature state, the lithium battery charge and discharge switch is in the off state, the solar panel and the lithium battery are in the common positive but not common negative state, when the solar panel voltage is higher than the lithium battery, the negative potential of the lithium battery is higher than that of the solar panel, NPN triode Q24 and PNP triode Q20 are sequentially turned on, the drain of CJ2301P-MOS tube Q31 obtains 4.5V level, at the same time, in the low temperature state, the comparator U5A is reversed, the 1 pin of the comparator U5A outputs low level, the gate of CJ2301P-MOS tube Q31 obtains 0V level, and CJ2301P-MOS tube Q31 is opened, and the subsequent NPN triode Q35, PNP triode Q29 and N-MOS tube Q19 are sequentially opened, and the heating is started.

[0017] Compared with the prior art, the beneficial effects of the present application are:

[0018] (1) The power module provides a stable and reliable power supply voltage for the subsequent detection circuit, the comparator U5A and the P-MOS tube Q31;

[0019] (2) When the system temperature is as low as the threshold temperature, the ambient temperature detection circuit outputs a low level signal, that is, the connection between the 100K resistor R and the gate of CJ2301P-MOS tube Q is low level, when the solar panel voltage is higher than the battery voltage, they are common positive, which means that the negative potential of the battery is higher than that of the solar panel, the negative of D and the drain of Q are high level VDD 4.5V, and CJ2301P-MOS tube Q is opened;

[0020] (3) The solar heating circuit can meet the heating demand of the lithium battery under low temperature condition, but does not consume the energy of the lithium battery. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 It is a low temperature heating circuit system structure diagram of the present application;

[0022] Figure 2 It is an ambient detection circuit diagram of the present application;

[0023] Figure 3 It is a solar panel detection circuit diagram of the present application;

[0024] Figure 4The schematic diagram of the driving switch module of the application;

[0025] Figure 5 The schematic diagram of the power supply circuit of the application.

[0026] In the figure: 1, low-temperature heating circuit system body; 2, power module; 3, environment detection circuit; 4, driving switch; 5, battery charging and discharging switch. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0028] Please refer to Figures 1-5 The application provides a technical solution: a solar low-temperature heating circuit system, comprising a low-temperature heating circuit system body, wherein the low-temperature heating circuit system body 1 is provided with a power module 2, an environment detection circuit 3, a driving switch 4, and a battery charging and discharging switch 5; the power module 2 is connected with a positive electrode of a lithium battery and a negative electrode of the lithium battery respectively; one connection end of the power module 2 is connected with one end of the environment detection circuit 3; the other end of the environment detection circuit 3 is connected with one end of the driving switch 4; one connection end of the driving switch is grounded; the other end of the driving switch 4 is connected with one end of a resistor R1; the other end of the resistor R1 is connected with a positive electrode of a solar panel; and one end of the battery charging and discharging switch 5 is connected with a negative electrode of the solar panel.

[0029] The power module 2 comprises a capacitor C35, a capacitor C36, a resistor R68, a resistor R71, a voltage stabilizing tube D15, an NPN triode Q25, a diode D11, the NPN triode Q25, the voltage stabilizing tube D15, and the resistor R71, which constitute a voltage stabilizing circuit; the resistor R71 is connected with a base and a collector of the NPN triode Q25; a negative electrode of the voltage stabilizing diode D15 is connected with the base of the NPN triode Q25, and a positive electrode is grounded; an emitter of the NPN triode Q25 is connected with a positive electrode of the diode D11; the resistor R68 constitutes a current limiting circuit and is connected with a positive electrode of a lithium battery and a collector of the triode Q25; the diode D11 constitutes an anti-reverse circuit, and a positive electrode is connected with the emitter of the NPN triode Q25, and a negative electrode is connected with an output power supply.

[0030] The capacitor C35 and the capacitor C36 constitute a filter circuit; the capacitor C35 is connected with positive and negative electrodes of the lithium battery; and the capacitor C36 is connected with positive and negative electrodes of a power supply output; the power module 2 provides a stable and reliable power supply voltage for a subsequent detection circuit, a comparator U5A, and a P-MOS tube Q31.

[0031] The environmental detection circuit 3 comprises 1M resistor R83, 200K resistor R89, 1M resistor R88, 1K resistor R102, thermistor NTC2, 1M resistor R79, 5.1M resistor R80, comparator U5A, 100K resistor R87;

[0032] The 1M resistor R83 and the 200K resistor R89 constitute a voltage dividing circuit, the 1M resistor R83 and the 200K resistor R89 are connected in series between the power supply and the ground, the middle of the 1M resistor R83 and the 200K resistor R89 is connected to the pin 3 of the U5A, the 1M resistor R88, the 1K resistor R102 and the thermistor NTC2 constitute an environmental temperature detection circuit, the R88, the R102 and the thermistor NTC2 are connected in series between the power supply and the ground, the middle of the 1M resistor R88 and the 1K resistor R102 is connected to the pin 2 of the comparator U5A, the pin 5 of the comparator U5A is connected to the power supply, the pin 2 of the comparator U5A is grounded, and the R87 connects the pin 1 of the comparator U5A and the pin 1 of the CJ2301P-MOS tube Q31.

[0033] The solar panel detection circuit on the low-temperature heating circuit system body 1 connected with the solar panel comprises 1M resistor R67, NPN triode Q24, diode D13, 3M resistor R64, 1M resistor R57, PNP triode Q20, diode D12, the 1M resistor R67, the NPN triode Q24 and the diode D13 constitute a solar panel detection circuit, the 1M resistor R67 is connected with the negative electrode of the lithium battery and the base of the NPN triode Q25, the positive electrode of the diode D13 is connected with the emitter of the NPN triode Q25, the negative electrode of the diode D13 is connected with the negative electrode of the solar panel, the 3M resistor R64, the 1M resistor R57, the PNP triode Q20 and the diode D12 constitute a switch circuit, the 3M resistor R64 is connected with the collector of the NPN triode Q24 and the base of the PNP triode Q20, the 1M resistor R57 is connected with the base and the collector of the PNP triode Q20, and the emitter of the PNP triode Q20 is connected with the positive electrode of the diode D12.

[0034] When the system temperature is lower than the threshold temperature, the environmental temperature detection circuit outputs a low-level signal, that is, the connection between the 100K resistor R87 and the gate of the CJ2301P-MOS tube Q31 is low-level, when the voltage of the solar panel is higher than the voltage of the storage battery, the two common anodes mean that the negative potential of the storage battery is higher than the negative potential of the solar panel, the negative electrode of the D12 and the drain of the Q31 are high-level VDD4.5V, and the CJ2301P-MOS tube Q31 is opened.

[0035] The driving switch 4 includes 100K resistor R82, 100K resistor R87, CJ2301P-MOS tube Q31, 470K resistor R97, 470 resistor R108, NPN triode Q35, 1M resistor R86, 470K resistor R78, PNP triode Q29, 200K resistor R85, N-MOS tube Q19, 470K resistor R98.

[0036] 100K resistor R82 connects the gate and drain of CJ2301P-MOS tube Q31, the gate of CJ2301P-MOS tube Q31 connects 100K resistor R87, the drain of CJ2301P-MOS tube Q31 connects the negative pole of D12, 470K resistor R97 connects the source of CJ2301P-MOS tube Q31 and the base of NPN triode Q35, 470 resistor R108 connects the base and emitter of NPN triode Q35, 1M resistor R86 connects the collector of NPN triode Q35 and the base of PNP triode Q29, 470K resistor R78 connects the base and collector of PNP triode Q29, 200K resistor R85 connects the emitter of PNP triode Q29 and the gate of N-MOS tube Q19, 470K resistor R98 connects the gate and source of N-MOS tube Q19, the source of N-MOS tube Q19 connects the negative pole of solar panel, the drain of N-MOS tube Q19 connects one end of heating film resistor, the other end of heating resistor connects the positive pole of solar panel, and the gate of N-MOS tube Q19 connects GND2.

[0037] When CJ2301P-MOS tube Q31 is opened, NPN triode Q35 forms base current, NPN triode Q35 is opened, PNP triode Q29 forms base current, PNP triode Q29 is opened, N-MOS tube Q19 gate is charged, N-MOS tube Q19 is opened, heating film resistor and solar panel form parallel relationship, and heating film resistor starts heating.

[0038] Embodiment 1,

[0039] The ambient temperature detection circuit includes 1M resistor R83, 200K resistor R89, 1M resistor R88, 1K resistor R102, thermistor NTC2, 1M resistor R79, 5.1M resistor R80, comparator U5A, 100K resistor R87.

[0040] 1M resistor R83, 200K resistor R89 constitute a voltage dividing circuit, 1M resistor R83 and 200K resistor R89 are connected in series between the power supply and the ground, the middle of 1M resistor R83 and 200K resistor R89 is connected to the 3 pin of U5A, 1M resistor R88, 1K resistor R102, NTC2 constitute an ambient temperature detection circuit, R88, R102, thermistor NTC2 are connected in series between the power supply and the ground, the middle of 1M resistor R88 and 1K resistor R102 is connected to the 2 pin of comparator U5A, the 5 pin of comparator U5A is connected to the power supply, the 2 pin of comparator U5A is grounded, R87 connects the 1 pin of comparator U5A and the 1 pin of CJ2301 P-MOS tube Q31.

[0041] Example 2,

[0042] 1M resistor R67, NPN transistor Q24, diode D13, 3M resistor R64, 1M resistor R57, PNP transistor Q20, diode D12, the 1M resistor R67, NPN transistor Q24, diode D13 constitute a solar panel detection circuit, 1M resistor R67 is connected to the negative of lithium battery and the base of NPN transistor Q25, the positive of diode D13 is connected to the emitter of NPN transistor Q25, the negative of diode D13 is connected to the negative of solar panel, 3M resistor R64, 1M resistor R57, PNP transistor Q20, diode D12 constitute a switching circuit, 3M resistor R64 is connected to the collector of NPN transistor Q24 and the base of PNP transistor Q20, 1M resistor R57 is connected to the base and collector of PNP transistor Q20, the emitter of PNP transistor Q20 is connected to the positive of diode D12.

[0043] Example 3

[0044] 100K resistor R82, 100K resistor R87, CJ2301 P-MOS tube Q31, 470K resistor R97, 470 resistor R108, NPN transistor Q35, 1M resistor R86, 470K resistor R78, PNP transistor Q29, 200K resistor R85, N-MOS tube Q19, 470K resistor R98 are included in the driving switch 4.

[0045] 100K resistor R82 connects the gate and drain of CJ2301P-MOS tube Q31, 100K resistor R87 connects the gate of CJ2301P-MOS tube Q31, the negative pole of D12 connects the drain of CJ2301P-MOS tube Q31, 470K resistor R97 connects the source of CJ2301P-MOS tube Q31 and the base of NPN triode Q35, 470 resistor R108 connects the base and emitter of NPN triode Q35, 1M resistor R86 connects the collector of NPN triode Q35 and the base of PNP triode Q29, 470K resistor R78 connects the base and collector of PNP triode Q29, 200K resistor R85 connects the emitter of PNP triode Q29 and the gate of N-MOS tube Q19, 470K resistor R98 connects the gate and source of N-MOS tube Q19, the source of N-MOS tube Q19 connects the negative pole of solar panel, the drain of N-MOS tube Q19 connects one end of heating film resistor, the other end of heating resistor connects the positive pole of solar panel.

[0046] The working method of the solar low-temperature heating circuit system:

[0047] In the initial state, the charge and discharge switch of the lithium battery is in the on state, the solar panel and the lithium battery are in the common positive and common negative state, the gate of CJ2301P-MOS tube Q31 is 4.5V, due to the cutoff effect of D12, the drain of CJ2301P-MOS tube Q31 is also 4.5V, Q31 is in the off state, and the subsequent driving switch circuit is also in the off state, and the system is not heated.

[0048] Step two, in the low-temperature state, the charge and discharge switch of the lithium battery is in the off state, the solar panel and the lithium battery are in the common positive but not common negative state, when the voltage of the solar panel is higher than that of the lithium battery, the negative potential of the lithium battery is higher than that of the solar panel, NPN triode Q24 and PNP triode Q20 are turned on in turn, the drain of CJ2301P-MOS tube Q31 obtains 4.5V level, at the same time, in the low-temperature state, the comparator U5A flips, the 1 pin of the comparator U5A outputs low level, the gate of CJ2301P-MOS tube Q31 obtains 0V level, CJ2301P-MOS tube Q31 is opened, and the subsequent NPN triode Q35, PNP triode Q29, N-MOS tube Q19 are opened in turn, and the heating is started.

[0049] The opening condition of the CJ2301P-MOS tube Q31 is that the drain of the CJ2301P-MOS tube Q31 obtains a 4.5V level and the gate of the CJ2301P-MOS tube Q31 obtains a 0V level, both of which are indispensable, thus, in the low temperature state, the gate of the CJ2301P-MOS tube Q31 obtains a 0V level, and the solar panel is higher than the lithium battery, the drain of the CJ2301P-MOS tube Q31 obtains a 4.5V level, both of which are indispensable.

[0050] The solar heating circuit can meet the heating demand of the lithium battery under the low temperature condition, but does not consume the energy of the lithium battery.

[0051] Although the embodiments of the present application have been shown and described, it is to be understood that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A solar low temperature heating circuitry comprising a low temperature heating circuitry body, characterized by: The low-temperature heating circuit system body (1) is provided with a power module (2), an environment detection circuit (3), a driving switch (4), a battery charging and discharging switch (5), the power module (2) is connected with the positive pole of the lithium battery and the negative pole of the lithium battery respectively, one end of the power module (2) is connected with one end of the environment detection circuit (3), the other end of the environment detection circuit (3) is connected with one end of the driving switch (4), one end of the driving switch is grounded, the other end of the driving switch (4) is connected with one end of the resistor R1, the other end of the resistor R1 is connected with the positive pole of the solar panel, one end of the battery charging and discharging switch (5) is connected with the negative pole of the solar panel, the power module (2) comprises a capacitor C35, a capacitor C36, a resistor R68, a resistor R71, a voltage stabilizing tube D15, an NPN triode Q25 and a diode D11; The NPN triode Q25, the voltage stabilizing tube D15 and the resistor R71 constitute a voltage stabilizing circuit, the resistor R71 is connected with the base and the collector of the NPN triode Q25, the negative pole of the voltage stabilizing diode D15 is connected with the base of the NPN triode Q25, the positive pole is grounded, the emitter of the NPN triode Q25 is connected with the positive pole of the diode D11, the resistor R68 constitutes a current limiting circuit and is connected with the positive pole of the lithium battery and the collector of the triode Q25, the diode D11 constitutes an anti-reverse circuit, the positive pole is connected with the emitter of the NPN triode Q25, and the negative pole is connected with an output power supply; The capacitor C35 and the capacitor C36 constitute a filter circuit, the capacitor C35 is connected with the positive and negative poles of the lithium battery, and the capacitor C36 is connected with the positive and negative poles of the power output; the environment detection circuit (3) comprises a 1M resistor R83, a 200K resistor R89, a 1M resistor R88, a 1K resistor R102, a thermistor NTC2, a 1M resistor R79, a 5.1M resistor R80, a comparator U5A and a 100K resistor R87; The 1M resistor R83 and the 200K resistor R89 constitute a voltage dividing circuit, the 1M resistor R83 and the 200K resistor R89 are connected in series between the power supply and the ground in sequence, the middle of the 1M resistor R83 and the 200K resistor R89 is connected to the 3 pin of the U5A, the 1M resistor R88, the 1K resistor R102 and the thermistor NTC2 constitute an environment temperature detection circuit, the R88, the R102 and the thermistor NTC2 are connected in series between the power supply and the ground in sequence, the middle of the 1M resistor R88 and the 1K resistor R102 is connected to the 2 pin of the comparator U5A, the 5 pin of the comparator U5A is connected to the power supply, the 2 pin of the comparator U5A is grounded, and the R87 is connected with the 1 pin of the comparator U5A and the 1 pin of the CJ2301P-MOS tube Q31; the solar panel detection circuit connected with the solar panel on the low-temperature heating circuit system body (1) comprises a 1M resistor R67, an NPN triode Q24, a diode D13, a 3M resistor R64, a 1M resistor R57, a PNP triode Q20 and a diode D12. The 1M resistor R67, NPN transistor Q24, diode D13 constitute a solar panel detection circuit, 1M resistor R67 connects the negative of lithium battery and the base of NPN transistor Q25, the positive of diode D13 connects the emitter of NPN transistor Q25, the negative of diode D13 connects the negative of solar panel, the 3M resistor R64, 1M resistor R57, PNP transistor Q20, diode D12 constitute a switch circuit, 3M resistor R64 connects the collector of NPN transistor Q24 and the base of PNP transistor Q20, 1M resistor R57 connects the base and collector of PNP transistor Q20, the emitter of PNP transistor Q20 connects the positive of diode D12.

2. A solar low temperature heating circuit system according to claim 1, characterized in that: The driving switch (4) includes 100K resistor R82, 100K resistor R87, CJ2301P-MOS tube Q31, 470K resistor R97, 470 resistor R108, NPN transistor Q35, 1M resistor R86, 470K resistor R78, PNP transistor Q29, 200K resistor R85, N-MOS tube Q19, 470K resistor R98; The 100K resistor R82 connects the gate and drain of CJ2301P-MOS tube Q31, the gate of CJ2301P-MOS tube Q31 connects 100K resistor R87, the drain of CJ2301P-MOS tube Q31 connects the negative of D12, 470K resistor R97 connects the source of CJ2301P-MOS tube Q31 and the base of NPN transistor Q35, 470 resistor R108 connects the base and emitter of NPN transistor Q35, 1M resistor R86 connects the collector of NPN transistor Q35 and the base of PNP transistor Q29, 470K resistor R78 connects the base and collector of PNP transistor Q29, 200K resistor R85 connects the emitter of PNP transistor Q29 and the gate of N-MOS tube Q19, 470K resistor R98 connects the gate and source of N-MOS tube Q19, the source of N-MOS tube Q19 connects the negative of solar panel, the drain of N-MOS tube Q19 connects one end of heating film resistor, the other end of heating resistor connects the positive of solar panel, the gate of N-MOS tube Q19 connects GND2 end.

3. The working method of the solar low-temperature heating circuit system of claim 2 comprises the following steps: Step one, in the initial state, the charge-discharge switch of lithium battery is in the on state, the solar panel and lithium battery are in the common positive and common negative state, the gate of CJ2301P-MOS tube Q31 is 4.5V, due to the cutoff of D12, the drain of CJ2301P-MOS tube Q31 is also 4.5V, Q31 is in the off state, the subsequent driving switch circuit is also in the off state, and the system is not heated. Step two, low temperature state, lithium battery charge and discharge switch is in the off state, the solar panel and lithium battery in the common positive but not the common negative state, when the solar panel voltage is higher than the lithium battery, the negative potential of lithium battery is higher than the negative potential of solar panel, NPN triode Q24, PNP triode Q20 are in turn turned on, the drain of CJ2301 P-MOS tube Q31 obtains 4.5V level, at the same time, in low temperature state, the comparator U5A flips, the 1 pin output of comparator U5A is low level, the gate of CJ2301 P-MOS tube Q31 obtains 0V level, CJ2301 P-MOS tube Q31 is opened, the subsequent NPN triode Q35, PNP triode Q29, N-MOS tube Q19 are in turn opened, and the heating is started.

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