CN218414774U

CN218414774U - Battery heating circuit, lithium battery and electronic equipment

Info

Publication number: CN218414774U
Application number: CN202222425534.1U
Authority: CN
Inventors: 高涛; 姚文奇; 刘祥松
Original assignee: Zhejiang Sunwoda Electronics Co Ltd
Current assignee: Zhejiang Sunwoda Electronics Co Ltd
Priority date: 2022-09-13
Filing date: 2022-09-13
Publication date: 2023-01-31
Anticipated expiration: 2032-09-13

Abstract

The application discloses battery heating circuit, lithium cell and electronic equipment belongs to battery technical field. The battery heating circuit includes: a battery for driving a load; the fuel gauge is connected with the battery; the voltage stabilizing unit is connected with the battery, and the enabling end of the voltage stabilizing unit is connected with the output end of the fuel gauge; the heating coil is connected with the output end of the voltage stabilizing unit; the fuel gauge is used for monitoring the working state of the battery, and the voltage stabilizing unit controls the heating coil to be turned on or off according to the working state. The battery heating circuit can control the switch of the heating coil and carry out safety protection on the battery according to the working state of the battery. The application of the electronic equipment can enable the battery to discharge with high power under the low-temperature environment, directly controls the output of the heating circuit and protects the heating circuit through the electricity meter, optimizes the low-temperature performance of the battery, and improves the low-temperature endurance time of the battery.

Description

Battery heating circuit, lithium battery and electronic equipment

Technical Field

The application belongs to the technical field of batteries, and particularly relates to a battery heating circuit, a lithium battery and electronic equipment.

Background

The activity of the internal substances of the battery is reduced in a low-temperature environment, and the electrolyte moves slowly, so that the transfer activity of ions between the positive electrode and the negative electrode of the battery is influenced, and the charge and discharge performance of the battery is reduced, therefore, the low-temperature discharge performance of the battery needs to be further optimized, the low-temperature high-power use requirement of the battery is met, and meanwhile, the safety protection of the battery in the low-temperature discharge process needs to be realized.

Disclosure of Invention

The purpose of the invention is as follows: the application provides a battery heating circuit which can heat a battery and effectively protect the battery according to the working state of the battery; another object of the present application is to provide a lithium battery including the above battery heating circuit; another object of the present application is to provide an electronic device including the above battery.

The technical scheme is as follows: the application provides a battery heating circuit, includes:

a battery for driving a load;

a fuel gauge connected to the battery;

the voltage stabilizing unit is connected with the battery, and an enabling end of the voltage stabilizing unit is connected with the output end of the fuel gauge;

the heating coil is connected with the output end of the voltage stabilizing unit;

the fuel gauge is used for monitoring the working state of the battery, and the voltage stabilizing unit controls the heating coil to be turned on or off according to the working state.

In some embodiments, the operating state of the battery includes voltage, current, operating temperature, and capacity of the battery flowing through the battery. When detecting that the battery is under-voltage, the battery is low in capacity, the battery is at high temperature and the like, the voltage stabilizing unit is controlled by the fuel gauge to output low level, and the heating of the heating coil is cut off.

In some embodiments, the load refers to a device for converting electric energy into other forms of energy, and is a general term for an electric appliance.

In some embodiments, the battery heating circuit further comprises:

the temperature detection unit, the temperature detection unit includes temperature sensor and first resistance, temperature sensor's input with the first pin of coulometer is connected, first resistance series connection insert the coulometer with between the temperature sensor.

In some embodiments, in order to facilitate the detection of the temperature of the battery by the temperature detection unit, the temperature sensor is attached to the battery.

In some embodiments, the battery heating circuit further comprises:

the current detection unit comprises a current sensor, the input end of the current sensor is respectively connected with the output end of the fuel gauge and the negative electrode of the load, and the output end of the current sensor is connected with the battery.

In some embodiments, the current sensor comprises:

a first end of the second resistor is connected with a second pin of the electricity meter;

a first end of the third resistor is connected with a third pin of the electricity meter;

a first end of the fourth resistor is respectively connected with a second end of the second resistor and the negative electrode of the battery, and a second end of the fourth resistor is respectively connected with a second end of the third resistor and the negative electrode of the load;

and the differential capacitor is respectively connected with the first end of the second resistor and the first end of the third resistor.

In some embodiments, the battery heating circuit further comprises: and the input end of the key unit is connected with the fourth pin of the electricity meter, and the output end of the key unit is connected with the negative electrode of the load.

In some embodiments, the battery heating circuit further comprises:

and the input end of the display unit is connected with a fourth pin of the fuel gauge, and the output end of the display unit is connected with the negative pole of the load.

In some embodiments, the battery heating circuit further comprises:

the input end of the primary protection circuit is connected with the anode of the battery, and the output end of the primary protection circuit is connected with the anode of the load; the primary protection circuit comprises a charging loop switch and a discharging loop switch, the charging loop switch is connected with a fifth pin of the electricity meter, and the discharging loop switch is connected with a sixth pin of the electricity meter

In some embodiments, the battery heating circuit further comprises:

the secondary protection circuit comprises a fuse and a secondary protection chip, wherein the first end of the fuse is connected with the battery, the second end of the fuse is connected with the charging loop switch, and the third end of the fuse is connected with the output end of the secondary protection chip;

and the power supply end of the secondary protection chip is connected with the battery.

In some embodiments, the present application further includes a lithium battery including the battery heating circuit.

In some embodiments, the present application further includes an electronic device comprising the lithium battery.

In some embodiments, the fuel gauge collects information of battery voltage, battery temperature, battery current and the like, calculates information of battery capacity, battery state and the like through coulomb integral, battery modeling and the like, and interactively communicates with an external host through a communication port such as I2C/SMBUS/HDQ and the like, and the first pin, the second pin, the third pin, the fourth pin, the fifth pin, the sixth pin and the like defined above are determined by the specific model of the fuel gauge used.

Has the advantages that: compared with the prior art, a battery heating circuit of this application includes: a battery; the fuel gauge is connected with the battery; the voltage stabilizing unit is connected with the battery, and the enabling end of the voltage stabilizing unit is connected with the output end of the fuel gauge; the heating coil is connected with the output end of the voltage stabilizing unit; the battery is used for driving the load, the fuel gauge is used for monitoring the working state of the battery, and the voltage stabilizing unit controls the heating coil to be turned on or turned off according to the working state. The battery heating circuit of this application can control opening and closing of heating coil to according to battery operating condition, judge and carry out the security protection when the battery is in excess temperature, under-voltage, overflow and low capacity to the battery. The lithium battery and the electronic equipment can enable the battery to discharge with high power under the low-temperature environment, output of the heating circuit and protection of the heating circuit are achieved through direct control of the fuel gauge, the low-temperature performance of the battery is optimized, and the low-temperature endurance time of the battery is prolonged.

Drawings

The technical solutions and other advantages of the present application will become apparent from the following detailed description of specific embodiments of the present application when taken in conjunction with the accompanying drawings.

Fig. 1 is a schematic structural diagram of a battery heating circuit according to an embodiment of the present disclosure;

fig. 2 is a schematic diagram of a pin structure of an electricity meter according to an embodiment of the present disclosure;

FIG. 3 is a schematic diagram of a connection of a temperature detecting unit according to an embodiment of the present disclosure;

FIG. 4 is a schematic diagram of a current structure of a current sensor according to an embodiment of the present disclosure;

fig. 5 is a connection diagram of a primary protection circuit according to an embodiment of the present disclosure;

fig. 6 is a schematic diagram of an operation flow of the over-temperature protection provided in the embodiment of the present application;

reference numeral, a battery-100, an electricity meter-101, a voltage stabilizing unit-102, a heating coil-103, a temperature detecting unit-104, a current detecting unit-105, a key unit-106, a display unit-107, a primary protection circuit-108, and a secondary protection circuit-109.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It should be apparent that the described embodiments are only a few embodiments of the present application, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

In the description of the present application, it is to be noted that, unless otherwise explicitly specified or limited, the terms "connected" and "connected" are to be interpreted broadly, e.g., as being fixed or detachable or integrally connected; may be mechanically connected, may be electrically connected or may be in communication with each other; they may be directly connected or indirectly connected through intervening media, or may be connected through the use of two elements or the interaction of two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as the case may be. In the description of the present application, "a plurality" means two or more unless specifically limited otherwise. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more features.

The following disclosure provides many different embodiments or examples for implementing different features of the application. In order to simplify the disclosure of the present application, specific example components and arrangements are described below. Of course, they are merely examples and are not intended to limit the present application.

Referring to fig. 1, the present application provides a battery heating circuit, including: a battery 100, an electricity meter 101, a voltage stabilization unit 102, a heating coil 103, a temperature detection unit 104, a current detection unit 105, a key unit 106, a display unit 107, a primary protection circuit 108, and a secondary protection circuit; wherein, the fuel gauge 101 is connected with the battery 100, and the fuel gauge 101 is used for detecting the working state of the battery 100; the voltage stabilizing unit 102 is connected with the battery 100, an enable pin of the voltage stabilizing unit 102 is connected with an output pin of the fuel gauge 101, and the voltage stabilizing unit 102 is used for controlling the on-off of the heating coil 103 according to the working state of the battery 100 monitored by the fuel gauge 101; the heating coil 103 is connected with an output pin of the voltage stabilizing unit 102, and the heating coil 103 is used for heating the battery 100 when the battery 100 is in a low-temperature environment; the output pin of the fuel gauge 101 is connected with the temperature detection unit 104, and the temperature detection unit 104 is used for detecting the working temperature of the battery 100; the current detection unit 105 is respectively connected with an output pin of the fuel gauge 101, a negative pole Pwr-of a load and a negative pole of the battery 100, and the current detection unit 105 is used for detecting the magnitude of current flowing through the battery 100; the key unit 106 is connected with an output pin of the electricity meter 101 and used for controlling the heating coil 103 to be turned on; the display unit 107 is connected to an output pin of the electricity meter 101, and is used for judging the operating state of the heating coil 103 according to the displayed result.

In some embodiments, the fuel gauge 101 and the voltage stabilizing unit 102 are directly connected to an output loop of the battery 100, when the battery 100 operates, the fuel gauge 101 detects an operating state of the battery 100, where the operating state includes voltage, current, temperature, capacity, and the like, and processes information of the obtained operating state, determines a relationship between parameters of actual operation of each information and parameters in a preset protection range of the battery 100, and then the fuel gauge 101 outputs a high level or a low level through an output pin to control the voltage stabilizing unit 102 to turn on or off the heating coil 103, on one hand, the fuel gauge 101 may control the heating coil 103 to be turned on or off, so that the battery 100 uses higher power at a lower temperature, and on the other hand, the operating state of the battery 100 may also be detected in real time, so that the battery 100 has a safety protection function such as over-temperature, under-voltage, over-current, and low capacity of the battery 100.

In some embodiments, the principle of the battery heating circuit for realizing safety protection such as over-temperature protection, under-voltage protection, over-current protection, battery low capacity protection and the like is as follows: when the battery 100 is started after the key unit 106 is pressed, and the current, the temperature and the capacity are within the set range, the electricity meter 101 outputs a high level to drive the voltage stabilizing unit 102 to normally work, so that the output end of the voltage stabilizing unit 102 controls the heating coil 103 to start working. When it is detected that the voltage supplied by the battery 100 is too low, the fuel gauge 101 outputs a low level to turn off the output of the voltage stabilizing unit 102, and then the heating coil 103 is turned off, so as to realize the under-voltage protection function. When the temperature detecting unit 104 detects that the temperature of the battery 100 is too high through the thermistor in the external circuit, the fuel gauge 101 outputs a low level to close the output of the voltage stabilizing unit 102, and further the heating coil 103 is closed, thereby realizing the over-temperature protection function. When the fuel gauge 101 detects that the current is too large through the current sensor of the current detection unit 105, the fuel gauge 101 outputs a low level to close the output of the voltage stabilization unit 102, and then the heating coil 103 is closed, so as to realize the overcurrent protection function. When the electricity meter 101 detects that the capacity of the battery 100 is lower than the preset range, the electricity meter 101 outputs a low level signal, thereby turning off the heating coil 103, and realizing low capacity protection of the battery 100.

In some embodiments, the fuel gauge 101 is of the BQ40z50 type, see fig. 2, PIN1, PIN2, PIN3, PIN4, PIN5, PIN9, PIN26, PIN27, PIN32 are PINs for connecting power supply and voltage sampling circuits; PIN6 and PIN8 are PINs for connecting a current sampling circuit; PIN10, PIN11, PIN12 and PIN13 are PINs for connecting a temperature sampling circuit; PINs 16, 17, 18, 19, 20, 21 and 22 are PINs for connecting an external interaction circuit; PIN23, PIN24, PIN25 are used to connect the PINs of the diode protection circuit 109;

PINs

28, 30, and 31 are PINs for connecting the primary protection circuit 108. When the electric meter 101 adopts a BQ40z50 model, a first pin of the electric meter 101 is defined as a TS4 pin, a second pin of the first electric meter 101 is defined as an SRP pin, a third pin of the electric meter 101 is defined as an SRN pin, a fourth pin of the electric meter 101 is defined as a leccc pin, a fifth pin of the electric meter 101 is defined as a CHG pin, and a sixth pin of the electric meter 101 is defined as a DSG pin.

In some embodiments, referring to fig. 1, the battery 100 may be composed of at least three sets of dry cells connected in series, and the fuel gauge 101 is connected to the positive and negative electrodes of the battery 100.

In some embodiments, referring to fig. 1, the electricity meter 101 has a built-in constant current capable of driving the voltage regulation unit 102, the voltage regulation unit 102 employs a TPS709 model LDO 3.3V regulator, an enable terminal EN of the voltage regulation unit 102 is connected to a LEDCC pin of the electricity meter 101, an input terminal VSS of the voltage regulation unit 102 is connected to a positive electrode of the battery 100, an output terminal OUT of the voltage regulation unit 102 is connected to the heating coil 103, and a ground terminal GND of the voltage regulation unit 102 is connected to a negative electrode of the battery 100. The TPS709 type LDO voltage regulator is sensitive to power consumption, high in temperature range precision, suitable for a system powered by a battery, and capable of sensitively controlling the on-off of the heating coil 103 according to the working state of the battery 100, so that the use safety of the battery 100 is improved.

In some embodiments, referring to fig. 3, the temperature detecting unit 104 includes a temperature sensor and a first resistor R1, the first resistor R1 is a negative temperature system thermistor, the temperature sensor is a DS18S20 type, and the temperature sensor is attached to the battery 100 and is used for directly collecting the temperature of the battery 100; one end of the first resistor R1 is connected with a first pin of the fuel gauge 101, the first pin of the fuel gauge 101 is a pin TS4, and the other end of the first resistor R1 is connected with the input end of the temperature sensor. The TS1 pin, TS2 pin, and TS3 pin of the electricity meter 101 are grounded through an external resistor R0 of 10k Ω to avoid pin floating.

In some embodiments, referring to fig. 1, the current detection unit 105 includes a current sensor, an input end of the current sensor is respectively connected to an output end of the fuel gauge 101 and a negative electrode Pwr "of the load, an output end of the current sensor is connected to the battery 100, the current sensor converts a current signal into a voltage signal through a sampling resistor, and the fuel gauge 101 obtains a current value by measuring a voltage drop across the sampling resistor.

In some embodiments, referring to fig. 4, since the resistance of the sampling resistor is large, the sampling resistor needs to be filtered and conditioned to avoid a small signal, and the current sensor includes: the circuit comprises a second resistor R2, a third resistor R3, a fourth resistor R4 and a differential capacitor C; the fourth resistor R4 is a sampling resistor, and the resistance values of the second resistor R2 and the third resistor R3 are 100 Ω. A first end of the second resistor R2 is connected with an SRP pin of the fuel gauge 101, and a second end of the second resistor R2 is connected with a first end of the fourth resistor R4; a first end of the third resistor R3 is connected with an SRN pin of the fuel gauge 101, and a second end of the third resistor R3 is connected with a second end of the fourth resistor R4; the first end of the fourth resistor R4 is further connected to the negative electrode of the battery 100, and the second end of the fourth resistor R4 is further connected to the negative electrode Pwr-of the load; two ends of the differential capacitor C are respectively connected with the first end of the second resistor R2 and the first end of the third resistor R3.

In some embodiments, the key unit 106 employs a toggle button, the signal input of the key unit 106 is connected to the LEDCC pin of the fuel gauge 101, and the output of the key unit 106 is connected to the negative pole Pwr-of the load.

In some embodiments, the display unit 107 is an LED lamp, the built-in constant current of the electricity meter 101 can also drive the LED lamp to display to indicate the electricity quantity, the heating condition or the battery failure, etc., the DISP pin of the electricity meter 101 is used to trigger the LED lamp to display, the signal input end of the display unit 107 is connected to the LED cc pin of the electricity meter 101, and the output end of the display unit 107 is connected to the negative pole Pwr-of the load.

In some embodiments, referring to fig. 1, the primary protection circuit 108 includes a charge loop switch connected to the CHG pin of the fuel gauge 101 and a discharge loop switch connected to the DSG pin of the fuel gauge 101. The charging loop switch adopts a control field effect transistor CFET, and the discharging loop switch adopts a depletion mode field effect transistor DFET. The model of the CFET is TPN6R303, and the model of the DFET is TPN6R303. The primary protection comprises the protection functions of battery overcharge, overdischarge, overcurrent, short circuit, high temperature, low temperature, charging overtime and the like.

In some embodiments, referring to fig. 5, the primary protection circuit 108 further includes a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and an eighth resistor R8; the drains of the charging loop switch CFET and the discharging loop switch DFET are connected to a VCC pin of the fuel gauge 101, the source of the charging loop switch CFET is connected to the positive electrode of the battery 100, and the source of the discharging loop switch DFET is connected to the positive electrode Pwr + of the load; a first end of the fifth resistor R5 is connected to the CHG pin of the fuel gauge 101, and a second end of the fifth resistor R5 is connected to the gate of the charge circuit switch CFET; a first end of the sixth resistor R6 is connected to the DSG pin of the fuel gauge 101, and a second end of the sixth resistor R6 is connected to the gate of the discharge loop switch DFET; the resistance values of the fifth resistor R5 and the sixth resistor R6 are 5.1k omega, and the fifth resistor R5 and the sixth resistor R6 are used for adjusting the on-off speed of the charging loop switch and the discharging loop switch; two ends of the seventh resistor R7 are respectively connected with the grid and the source of the charging loop switch CFET, and two ends of the eighth resistor are respectively connected with the grid and the source of the discharging loop switch DFET; the seventh resistor R7 and the eighth resistor R8 have a resistance of 10M Ω, which is used to ensure that the charging loop switch and the discharging loop switch can be completely turned off.

In some embodiments, referring to fig. 1, the secondary protection circuit 109 includes a fuse and a secondary protection chip, the secondary protection chip is a BQ2974, and the secondary protection chip is connected to the positive electrode and the negative electrode of the battery 100; the secondary protection comprises battery core failure, protection component failure, use environment safety risk and the like, the secondary protection depends on a fuse, and when a secondary protection condition is triggered, the secondary protection chip outputs high voltage to fuse the fuse. The fuse adopts a three-terminal fuse, a first terminal of the fuse is connected with the positive electrode of the battery 100, a second terminal of the fuse is connected with the source electrode of the charging loop switch CFET, and a third terminal of the fuse is connected with the output end of the secondary protection chip.

In some embodiments, the blow command of the FUSE may also be issued through the FUSE pin of the fuel gauge 101. If the FUSE pin of the electricity meter 101 is not used, the FUSE pin needs to be grounded.

In some embodiments, the electricity meter 101 generally employs a communication protocol such as I2C, SMBUS, or HDQ. I2C is a two-wire communication including a clock line SCL and a data line SDA; SMBUS is also a two-line communication, including a clock line SMBC and a data line SMBD; HDQ is single wire communication.

In some embodiments, the battery heating circuit may be formed on the circuit board in an integrated manner, the circuit board is assembled with a battery core and the like to form a lithium battery, the lithium battery controls the heating coil 103 to be turned on or off through the electricity meter 101 of the battery heating circuit, and monitors working states of the battery, such as voltage, current, temperature, capacity and the like, in real time through the electricity meter 101, when undervoltage, overcurrent, low battery capacity or high battery temperature is detected, the enable terminal voltage of the voltage stabilizing unit 102 is pulled down through the electricity meter 101, so as to effectively cut off the output of the heating coil 103, thereby realizing safety protection of the lithium battery.

In some embodiments, the lithium battery is used for driving the electronic device, after the electronic device uses the lithium battery, high-power discharge can be performed in a low-temperature environment (-30 ℃), the output and protection of the heating circuit are directly controlled through the IC chip of the fuel gauge 101, the damage of the battery is protected in time, the low-temperature performance of the battery is optimized, and the low-temperature endurance time is prolonged.

In some embodiments, the electronic device may include a laptop, a cell phone, a tablet, and the like.

In some embodiments, referring to fig. 6, taking the over-temperature protection as an example, after the notebook computer adopts the lithium battery with the battery protection circuit, the operation process includes: after the battery 100 enters a sleep mode, a low-temperature heating switch button as a key unit 106 is pressed, then the electricity meter 101 performs judgment, when the battery temperature is judged to be less than an IC setting parameter LT start T of the electricity meter 101 and the battery SOC is judged to be greater than a setting parameter LT RSOC, the electricity meter 101 controls the LDO voltage stabilizer to be turned on, the heating coil 103 starts heating, and the LED lamp of the display unit 107 is turned on; when the heating time is judged to exceed the setting parameter LT DSG timeout or the battery temperature is larger than the setting parameter LT stop T, the electricity meter 101 controls the LDO voltage stabilizer to be closed, the heating coil 103 stops heating, and the LED indicator lamp is turned off.

The above detailed description is given to the battery heating circuit, the lithium battery and the electronic device provided in the embodiments of the present application, and specific examples are applied in the present application to explain the principle and the implementation of the present application, and the description of the above embodiments is only used to help understanding the technical solutions and the core ideas of the present application; those of ordinary skill in the art will understand that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications or substitutions do not depart from the spirit and scope of the present disclosure as defined by the appended claims.

Claims

1. A battery heating circuit, comprising:

a battery (100), the battery (100) being for driving a load;

an electricity meter (101), the electricity meter (101) being connected to the battery (100);

a voltage stabilizing unit (102), wherein the voltage stabilizing unit (102) is connected with the battery (100), and an enabling end of the voltage stabilizing unit (102) is connected with an output end of the fuel gauge (101);

the heating coil (103), the heating coil (103) is connected with the output end of the voltage stabilizing unit (102);

the electricity meter (101) is used for monitoring the working state of the battery (100), and the voltage stabilizing unit (102) controls the heating coil (103) to be turned on or off according to the working state.

2. The battery heating circuit of claim 1, further comprising:

the temperature detection unit (104) comprises a temperature sensor and a first resistor, one end of the first resistor is connected with a first pin of the fuel gauge (101), and the other end of the first resistor is connected with the input end of the temperature sensor.

3. The battery heating circuit of claim 1, further comprising:

a current detection unit (105) comprising a current sensor, the input of the current sensor being connected to the output of the fuel gauge (101) and to the negative pole of the load, respectively, the output of the current sensor being connected to the battery (100).

4. The battery heating circuit of claim 3, wherein the current sensor comprises:

a second resistor, a first end of the second resistor being connected to a second pin of the fuel gauge (101);

a third resistor, a first end of the third resistor being connected to a third pin of the fuel gauge (101);

5. The battery heating circuit of claim 1, further comprising: the input end of the key unit (106) is connected with the fourth pin of the electricity meter (101), and the output end of the key unit (106) is connected with the negative electrode of the load.

6. The battery heating circuit of claim 1, further comprising:

the input end of the display unit (107) is connected with the fourth pin of the electricity meter (101), and the output end of the display unit (107) is connected with the negative pole of the load.

7. The battery heating circuit of claim 1, further comprising:

the input end of the primary protection circuit (108) is connected with the anode of the battery, and the output end of the primary protection circuit (108) is connected with the anode of the load; the primary protection circuit (108) comprises a charging loop switch and a discharging loop switch, the charging loop switch is connected with a fifth pin of the fuel gauge (101), and the discharging loop switch is connected with a sixth pin of the fuel gauge (101).

8. The battery heating circuit of claim 7, further comprising:

the secondary protection circuit (109) comprises a fuse and a secondary protection chip, a first end of the fuse is connected with the battery (100), a second end of the fuse is connected with the charging loop switch, and a third end of the fuse is connected with an output end of the secondary protection chip;

and the power supply end of the secondary protection chip is connected with the battery (100).

9. A lithium battery comprising a battery heating circuit according to any one of claims 1 to 8.

10. An electronic device characterized by comprising the lithium battery of claim 9.