Heating film protection circuit, protection device and battery pack

Abstract

The utility model belongs to the technical field of circuits, and provides a heating film protection circuit, a protection device and a battery pack. The heating film protection circuit comprises a temperature detection circuit, a temperature protection circuit and an isolation transmission circuit, the temperature detection circuit is in contact with the heating film, the temperature protection circuit is connected with the temperature detection circuit, and the isolation transmission circuit is arranged between the temperature protection circuit and the heating control circuit. The heating film protection circuit adopts a pure hardware control mode, the power supply loop of the heating film is timely disconnected and the safety of the battery pack is ensured by detecting the temperature of the heating film when the heating film is possibly uncontrolled, and the failure rate can be reduced and the stability of the circuit can be improved by adopting the pure hardware mode.

Description

Technical Field

[0001] The present application belongs to the field of circuit technology, and in particular relates to a heating film protection circuit, a protection device and a battery pack. Background Art

[0002] With the development of science and technology and the requirements of the social environment, household energy storage has been paid more and more attention by people. The important component of household energy storage is the battery pack. In the cold winter in the north, the ambient temperature of the battery pack is very low, which leads to the low temperature of the battery pack itself. The battery pack works at a relatively low temperature, which will affect the life of the battery pack. Especially when charging the battery, if the temperature of the battery pack is lower than the appropriate operating temperature, the life of the battery pack will be greatly reduced. At present, the battery pack is generally heated by heating film, PTC (Positive Temperature Coefficient) heater or liquid flow heating. However, the heating control circuit of the existing heating film may be out of control when working for a long time, resulting in the heating film being out of control and causing safety problems. Utility Model Content

[0003] The purpose of the present application is to provide a heating film protection circuit, a protection device and a battery pack, aiming to solve the problem that the existing heating control circuit may become out of control when working for a long time, resulting in the heating film being out of control and causing safety problems.

[0004] A first aspect of an embodiment of the present application provides a heating film protection circuit, which is applied to a battery pack, and the battery pack comprises: a heating film and a heating control circuit, wherein the heating film protection circuit is connected to the heating control circuit and contacts the heating film, and the heating film protection circuit comprises:

[0005] A temperature detection circuit, in contact with the heating film, for detecting the temperature of the heating film and generating a temperature detection signal;

[0006] A temperature protection circuit, connected to the temperature detection circuit, for receiving the temperature detection signal and generating an over-temperature protection signal when the voltage value of the temperature detection signal is greater than a preset temperature value;

[0007] The isolation transmission circuit is arranged between the temperature protection circuit and the heating control circuit, and is used for receiving the over-temperature protection signal, isolating the over-temperature protection signal, and outputting it to the heating control circuit to control the working state of the heating control circuit.

[0008] In one embodiment, the temperature detection circuit comprises:

[0009] At least one thermistor, wherein a first end of the at least one thermistor is connected to the negative output end of the battery pack, a second end of the at least one thermistor is connected to the temperature protection circuit, and the at least one thermistor is in contact with the heating film.

[0010] In one embodiment, the temperature protection circuit includes: a first resistor, a second resistor, a third resistor and a first comparator; wherein,

[0011] The first end of the first resistor is connected to the first power supply, the second end of the first resistor is connected to the non-inverting input terminal of the first comparator, the first end of the second resistor is connected to the first power supply, the second end of the second resistor is connected to the inverting input terminal of the first comparator, the first end of the third resistor is connected to the inverting input terminal of the first comparator, the second end of the third resistor is connected to the negative output terminal of the battery pack, and the output terminal of the first comparator is connected to the isolation transmission circuit.

[0012] In one embodiment, the isolation transmission circuit comprises:

[0013] At least one isolation unit, a first end of the at least one isolation unit is connected to the temperature protection circuit, and a second end of the at least one isolation unit is connected to the heating control circuit.

[0014] In one embodiment, the at least one isolation unit comprises:

[0015] At least one first diode, a first end of the at least one first diode is connected to the temperature protection circuit, and a second end of the at least one first diode is connected to the heating control circuit.

[0016] In one embodiment, the heating film protection circuit further includes:

[0017] A feedback circuit is connected to the temperature protection circuit, and is used to receive the over-temperature protection signal, generate a temperature feedback signal according to the over-temperature protection signal, and output the temperature feedback signal to the temperature protection circuit.

[0018] In one embodiment, the feedback circuit includes: a fourth resistor, a first end of the fourth resistor is connected to the output end of the temperature protection circuit, and a second end of the fourth resistor is connected to the input end of the temperature protection circuit.

[0019] In one embodiment, the temperature protection circuit further includes: a first capacitor, a second capacitor and a third capacitor; wherein,

[0020] The first end of the first capacitor is connected to the first end of the at least one thermistor, the second end of the first capacitor is connected to the second end of the at least one thermistor, the first end of the second capacitor is connected to the non-inverting input of the first comparator, the second end of the second capacitor is connected to the inverting input of the first comparator, the first end of the third capacitor is connected to the inverting input of the first comparator, and the second end of the third capacitor is connected to the negative output of the battery pack.

[0021] A second aspect of an embodiment of the present application provides a protection device, which includes a heating film protection circuit as described in any one of the above items.

[0022] A third aspect of the embodiments of the present application provides a battery pack, the battery pack comprising: a battery cell, a positive terminal, a negative output terminal, a heating film, and a heating control circuit, the heating film being connected between the positive terminal and the negative output terminal, and the heating film being in contact with the battery cell;

[0023] The heating control circuit is arranged between the heating film and the negative output terminal, and is used to control the working state of the heating film;

[0024] The battery pack further comprises a heating film protection circuit as described in any one of the above items, wherein the heating film protection circuit is connected to the heating control circuit, and the heating film protection circuit is in contact with the heating film;

[0025] The heating film protection circuit is used to control the working state of the heating control circuit.

[0026] Compared with the prior art, the embodiments of the present application have the following beneficial effects: the heating film protection circuit includes: a temperature detection circuit, a temperature protection circuit and an isolation transmission circuit, the temperature detection circuit is in contact with the heating film, the temperature protection circuit is connected to the temperature detection circuit, and the isolation transmission circuit is arranged between the temperature protection circuit and the heating control circuit. The heating film protection circuit adopts a pure hardware control form, by detecting the temperature of the heating film, when it is found that the heating film may not be controlled, the power supply circuit of the heating film is disconnected in time to ensure the safety of the battery pack, and by adopting a pure hardware method, the failure rate can be reduced and the stability of the circuit can be improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A schematic diagram of a heating film protection circuit provided in one embodiment of the present application Figure 1 ;

[0028] Figure 2 A schematic diagram of a heating film protection circuit provided in one embodiment of the present application Figure 2 ;

[0029] Figure 3A specific circuit diagram of a heating film protection circuit provided by an embodiment of the present application;

[0030] Figure 4 A schematic diagram of the structure of a battery pack provided in accordance with an embodiment of the present application. DETAILED DESCRIPTION

[0031] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0032] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0033] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0034] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0035] With the development of science and technology and the requirements of the social environment, household energy storage is increasingly valued by people, and the battery pack is an important component of household energy storage. In the cold winter in the north, the ambient temperature of the battery pack is very low, resulting in a low temperature for the battery pack itself. The battery pack works at a relatively low temperature, which will affect the life of the battery pack, especially when charging the battery. If the temperature of the battery pack is lower than the appropriate operating temperature, the life of the battery pack will be greatly reduced. At present, the battery pack is generally heated by heating film, PTC (Positive Temperature Coefficient) heater or liquid flow heating. However, the existing heating film protection circuit may be out of control when working for a long time, resulting in the heating film being out of control and causing safety problems.

[0036] In order to solve the above technical problems, refer to Figure 1 As shown, an embodiment of the present application provides a heating film protection circuit, which is applied to a battery pack. The battery pack includes: a heating film 100 and a heating control circuit 200. The heating film protection circuit is connected to the heating control circuit 200, and the heating film protection circuit is in contact with the heating film 100. The heating film protection circuit includes: a temperature detection circuit 10, a temperature protection circuit 20 and an isolation transmission circuit 30.

[0037] Specifically, the temperature detection circuit 10 is in contact with the heating film 100, and the temperature detection circuit 10 is used to detect the temperature of the heating film 100 and generate a temperature detection signal. The temperature protection circuit 20 is connected to the temperature detection circuit 10, and the temperature protection circuit 20 is used to receive the temperature detection signal, and when the voltage value of the temperature detection signal is greater than the preset temperature value, an over-temperature protection signal is generated. The isolation transmission circuit 30 is arranged between the temperature protection circuit 20 and the heating control circuit 200, and the isolation transmission circuit 30 is used to receive the over-temperature protection signal, and after isolating the over-temperature protection signal, output it to the heating control circuit 200 to control the working state of the heating control circuit 200.

[0038] In this embodiment, the heating film protection circuit is applied to the battery pack. When the battery pack is working normally, the heating control circuit 200 controls the working state of the heating film 100. However, due to the long-term operation of the heating control circuit 200, control confusion may sometimes occur. The heating film protection circuit of the present application is used to force the heating control circuit 200 to be in a disconnected working state when the heating control circuit 200 fails and cannot work normally, resulting in the heating film 100 being out of control, forcibly cutting off the power supply circuit of the heating film 100, causing the heating film 100 to stop working and prevent danger.

[0039] In this embodiment, the temperature detection circuit 10 is in contact with the heating film 100. For example, the temperature detection circuit 10 can be in contact with the heating film 100 in the form of a patch, and the temperature detection circuit 10 is used to detect the temperature of the heating film 100 and generate a temperature detection signal. For another example, the temperature detection circuit 10 can detect the temperature of the heating film 100 in real time, and generate a temperature detection signal from the temperature of the heating film 100. By detecting the temperature of the heating film 100 in real time, the user can timely understand the temperature of the heating film 100, which provides a guarantee for the accurate and stable operation of the heating film protection circuit.

[0040] In the present embodiment, the temperature protection circuit 20 is used to receive the temperature detection signal, and when the voltage value of the temperature detection signal is greater than the preset temperature value, an over-temperature protection signal is generated. Specifically, when the voltage value of the temperature detection signal is greater than the preset temperature value, it means that the temperature of the heating film 100 is too high at this time, and the heating control circuit 200 may be in an uncontrolled situation, and there may be a possibility of danger. At this time, it is necessary to control the heating film 100 to stop working, and the temperature protection circuit 20 generates an over-temperature protection signal at this time. On the contrary, when the voltage value of the temperature detection signal is less than or equal to the preset temperature value, it means that the temperature of the heating film 100 is within a reasonable range at this time, and the heating film 100 is in a controlled situation. Generally, there is no danger at this time. At this time, the temperature protection circuit 20 does not need to intervene in the work, and the temperature protection circuit 20 does not generate an over-temperature protection signal at this time. By setting the temperature protection circuit 20, the heating film 100 can generate an over-temperature protection signal when the temperature is too high and exceeds the preset range, and the working state of the heating control circuit 200 can be controlled in time, that is, the working state of the heating film 100 can be controlled in time, so as to ensure the safety of the battery pack.

[0041] In this embodiment, the isolation transmission circuit 30 is used to receive the over-temperature protection signal, and after isolating the over-temperature protection signal, output it to the heating control circuit 200 to control the working state of the heating control circuit 200. Specifically, the isolation transmission circuit 30 is used to isolate and transmit the over-temperature protection signal. At the same time, the isolation transmission circuit 30 can also isolate the temperature protection circuit 20 and the heating control circuit 200 to prevent the temperature protection circuit 20 and the heating control circuit 200 from interfering with each other. For example, the isolation transmission circuit 30 can prevent the signal at the end of the heating control circuit 200 from being output to the temperature protection circuit 20, resulting in damage to the temperature protection circuit 20. By setting the isolation transmission circuit 30, the stability of the circuit can be improved.

[0042] In this embodiment, the heating film protection circuit adopts a pure hardware control form. By detecting the temperature of the heating film 100, when it is found that the heating film 100 may be out of control, the power supply circuit of the heating film 100 is disconnected in time to ensure the safety of the battery pack. By adopting a pure hardware approach, the failure rate can be reduced and the stability of the circuit can be improved.

[0043] In one embodiment, reference Figure 2 As shown, the heating film protection circuit further includes: a feedback circuit 40.

[0044] Specifically, the feedback circuit 40 is connected to the temperature protection circuit 20, and the feedback circuit 40 is used to receive the over-temperature protection signal, generate a temperature feedback signal according to the over-temperature protection signal, and output the temperature feedback signal to the temperature protection circuit 20. When the output end of the temperature protection circuit 20 outputs the over-temperature protection signal, the feedback circuit 40 will generate a temperature feedback signal according to the over-temperature protection signal, and further feed back to the input end of the temperature protection circuit 20, thereby realizing signal feedback.

[0045] In one embodiment, reference Figure 3 As shown, the temperature detection circuit 10 includes: at least one thermistor.

[0046] Specifically, at least one thermistor, a first end of the at least one thermistor is connected to the negative output terminal P- of the battery pack, a second end of the at least one thermistor is connected to the temperature protection circuit 20, and the at least one thermistor is in contact with the heating film 100.

[0047] In this embodiment, at least one thermistor is in contact with the heating film 100, and the at least one thermistor is used to detect the temperature of the heating film 100 and generate a temperature detection signal. For example, the resistance of the at least one thermistor changes with the temperature. When the temperature of the heating film 100 changes, the resistance of the at least one thermistor also changes. In this embodiment, the temperature of the heating film 100 can be monitored by reflecting the temperature of the heating film 100 through the change of the resistance of the at least one thermistor.

[0048] In one embodiment, reference Figure 3 As shown, at least one thermistor may be a first thermistor NTC1 (Negative Temperature Coefficient thermistor). The first thermistor NTC1 is a negative temperature coefficient thermistor. The first thermistor NTC1 is used to detect the temperature of the heating film 100. When the temperature of the heating film 100 increases, the resistance of the first thermistor NTC1 decreases. Figure 3As shown, the first end of the first thermistor NTC1 is connected to the negative output terminal P- of the battery pack, and the second end of the first thermistor NTC1 is connected to the temperature protection circuit 20 (more specifically, connected to the non-inverting input terminal of the first comparator). When the temperature of the heating film 100 is too high, the resistance of the first thermistor NTC1 will be reduced to a preset value, thereby lowering the voltage of the non-inverting input terminal of the first comparator. By setting the first thermistor NTC1, the temperature of the heating film 100 can be monitored.

[0049] In one embodiment, reference Figure 3 As shown, the temperature protection circuit 20 includes: a first resistor R1, a second resistor R2, a third resistor R4 and a first comparator U1.

[0050] Specifically, the first end of the first resistor R1 is connected to the first power supply, the second end of the first resistor R1 is connected to the non-inverting input terminal of the first comparator U1, the first end of the second resistor R2 is connected to the first power supply, the second end of the second resistor R2 is connected to the inverting input terminal of the first comparator U1, the first end of the third resistor R4 is connected to the inverting input terminal of the first comparator U1, the second end of the third resistor R4 is connected to the negative output terminal P- of the battery pack, and the output terminal of the first comparator U1 is connected to the isolation transmission circuit 30.

[0051] In this embodiment, the first resistor R1, the second resistor R2 and the third resistor R4 are all voltage-dividing resistors for dividing the 12V voltage output by the first power supply. By setting the voltage-dividing resistors, the voltage input to the first comparator U1 can be within a reasonable range, thereby increasing the stability of the circuit.

[0052] In one embodiment, the isolation transmission circuit 30 includes: at least one isolation unit.

[0053] Specifically, the first end of at least one isolation unit is connected to the temperature protection circuit 20, and the second end of at least one isolation unit is connected to the heating control circuit 200. In this embodiment, at least one isolation unit is used to isolate and transmit the over-temperature protection signal, and at least one isolation unit can also isolate the temperature protection circuit 20 and the heating control circuit 200 to prevent the temperature protection circuit 20 and the heating control circuit 200 from interfering with each other. For example, at least one isolation unit can prevent the signal at the end of the heating control circuit 200 from being output to the temperature protection circuit 20, resulting in damage to the temperature protection circuit 20. By setting at least one isolation unit, the stability of the circuit can be improved.

[0054] In one embodiment, the at least one isolation unit includes: at least one first diode.

[0055] Specifically, the first end (cathode) of at least one first diode is connected to the temperature protection circuit 20, and the second end (anode) of at least one first diode is connected to the heating control circuit 200. Figure 3 As shown, in the present embodiment, at least one first diode may be a first diode D1. The function of the first diode D1 is to prevent the high level output by the first comparator U1 from turning on the heating control circuit 200. The first diode D1 uses a Schottky diode, and utilizes the unidirectional conduction characteristic of the diode to block the high level output by the first comparator U1 from turning on the heating control circuit 200. At the same time, it can also realize that when the low level (for example, an over-temperature protection signal) is output by the first comparator U1, the switch tube in the heating control circuit 200 is cut off. By setting the first switch tube Q1, the stability of the circuit can be ensured.

[0056] In one embodiment, reference Figure 3 As shown, the feedback circuit 40 includes: a fourth resistor R4. Specifically, a first end of the fourth resistor R4 is connected to the output end of the temperature protection circuit 20, and a second end of the fourth resistor R4 is connected to the input end of the temperature protection circuit 20. In this embodiment, the fourth resistor R4 functions as positive feedback. When the output end of the first comparator U1 changes from a high level to an output low level, the voltage of the in-phase input end of the first comparator U1 is further lowered by setting the fourth resistor R4, so as to prevent the first comparator U1 from hiccuping, thereby ensuring the stability of the circuit.

[0057] In one embodiment, reference Figure 3 As shown, the temperature protection circuit 20 further includes: a first capacitor C1, a second capacitor C2 and a third capacitor C3.

[0058] Specifically, the first end of the first capacitor C1 is connected to the first end of at least one thermistor (first thermistor NTC1), the second end of the first capacitor C1 is connected to the second end of at least one thermistor, the first end of the second capacitor C2 is connected to the non-inverting input end of the first comparator U1, the second end of the second capacitor C2 is connected to the inverting input end of the first comparator U1, the first end of the third capacitor C3 is connected to the inverting input end of the first comparator U1, the second end of the third capacitor C3 is connected to the negative output end P- of the battery pack, the power supply end of the first comparator U1 is connected to the 12V voltage, and the ground end of the first comparator U1 is connected to the negative output end P- of the battery pack. By setting the first capacitor C1, the second capacitor C2 and the third capacitor C3, the voltages of the non-inverting input end (+) and the inverting input end (-) of the first comparator U1 can be filtered to filter out impurity signals, thereby improving the stability of the circuit.

[0059] In one embodiment, reference Figure 3As shown, the temperature protection circuit 20 further includes a fifth resistor R5, a first end of the fifth resistor R5 is connected to a 12V voltage, and a second end of the fifth resistor R5 is connected to the output end of the first comparator U1. In this embodiment, the fifth resistor R5 is a pull-up resistor, and the fifth resistor R5 ensures that a high level is maintained when the first comparator U1 does not output an over-temperature protection signal, thereby avoiding circuit disorder.

[0060] In one embodiment, reference Figure 3 As shown, the heating control circuit 200 includes: a first driving chip U2, a sixth resistor R6, a second diode D2, a fourth capacitor C4, a seventh resistor R7, an eighth resistor R8 and a first switch tube Q1.

[0061] Specifically, the power supply terminal VCC of the first driver chip U2 is connected to a 12V voltage, the power supply terminal VCC of the first driver chip U2 is connected in series with a fourth capacitor C4 and then grounded, the power supply terminal VCC of the first driver chip U2 is also connected in series with a second diode D2 and then connected to a high floating terminal VB of the first driver chip U2, the high floating terminal VB of the first driver chip U2 is also connected to a 12V voltage, the input terminal HIN of the first driver chip U2 is connected to a main control circuit (the main control circuit is used to control the opening or closing of the heating control circuit 200, for example, when the heating control circuit 200 needs to be turned on, the main control circuit controls the heating control circuit 200 to be turned on) through a port HEAT EN, the input terminal HIN of the first driver chip U2 is also connected in series with a sixth resistor R6 and then grounded, the output terminal HO of the first driver chip U2 is connected in series with a seventh resistor R7 and then connected to the negative output terminal P- of the battery pack, the high-end floating ground terminal VS of the first driver chip U2 is connected to the negative output terminal P-, and the low-channel logic signal input level terminal LIN and the ground terminal GND of the first driver chip U2 are both grounded.

[0062] In this embodiment, reference Figure 3 As shown, the fourth capacitor C4 is a filter capacitor, the sixth resistor R6 is a pull-down resistor, the second diode D2 has a unidirectional conduction function, and the second diode D2 has an isolation function. When the battery pack does not need to discharge and the discharge switch tube of the battery pack is disconnected, P+ and P- are connected with a load at this time. Then, when the charge and discharge switch tube is disconnected, there will be a voltage at P+ at P- (generally, the voltage at P+ is 60V, so there will also be a large voltage at P- at this time). At this time, D2 is used to isolate the voltage at P- and the first power supply (12V) to prevent the voltage at P- from breaking through the first power supply and the single-chip microcomputer, thereby improving the stability of the circuit.

[0063] For further information, please refer to Figure 3As shown, the first end of the seventh resistor R7 and the first end of the eighth resistor R8 are connected to the output terminal HO of the first driving chip U2, the second end of the seventh resistor R7 is connected to the negative output terminal P-, the second end of the eighth resistor R8 is connected to the control end of the first switch tube Q1, the first end of the first switch tube Q1 is connected to the negative output terminal P-, and the second end of the first switch tube Q1 is connected to the heating film 100 (indicated by PI in the figure).

[0064] In this embodiment, the first switch tube Q1 is used to control the connection state between the heating film 100 (indicated by PI in the figure) and the negative output terminal P-. The seventh resistor R7 is a pull-down resistor. The function of the seventh resistor R7 is to increase the closing speed when the first switch tube Q1 is disconnected (cut off), and when the first switch tube Q1 is not needed to be turned on, the driving signal of the first switch tube Q1 can be stably pulled down. By setting the seventh resistor R7, the eighth resistor R8 and the first switch tube Q1, the working state of the heating film 100 can be stably and safely controlled.

[0065] In one embodiment, the resistance value of the seventh resistor R7 may range from 1K to 10K.

[0066] In one embodiment, reference Figure 3 As shown, the heating control circuit 200 further includes: a third diode D3. Specifically, a first end of the third diode D3 is connected to a second end of the first switch tube Q1, and a second end of the third diode D3 is connected to a positive terminal B+ of the battery pack. The third diode D3 is used to release the residual voltage on the second diode D2 in time when the first switch tube Q1 is disconnected, thereby ensuring the stability of the circuit.

[0067] In one embodiment, reference Figure 3 As shown, the anode of the first diode D1 is connected to the first end of the eighth resistor R8, and the cathode of the first diode D1 is connected to the output end of the first comparator U1. The function of the first diode D1 is to prevent the high level output by the first comparator U1 from turning on the first switch tube Q1. The first diode D1 uses a Schottky diode, and utilizes the unidirectional conduction characteristic of the diode to block the high level output by the first comparator U1 from turning on the first switch tube Q1. At the same time, it can also achieve that when the low level (for example, the over-temperature protection signal) output by the first comparator U1 is turned off, the first switch tube Q1 is turned off. By setting the first switch tube Q1, the stability of the circuit can be guaranteed.

[0068] In one embodiment, the first thermistor NTC1 is a thermistor with a negative temperature coefficient. As the temperature of the heating film 100 increases, its resistance decreases. When the temperature of the heating film 100 increases and the resistance of the first thermistor NTC1 drops to a certain value, the voltage at the non-inverting input terminal of the first comparator U1 is less than the voltage at the inverting input terminal, and the output terminal of the first comparator U1 will output a low level (over-temperature protection signal), forcing the first switch tube Q1 not to turn on.

[0069] An embodiment of the present application further provides a protection device, which includes a heating film protection circuit as described above.

[0070] In this embodiment, the above-mentioned heating film protection circuit is integrated into the protection device. Since the temperature protection circuit 20 and the isolation transmission circuit 30 are provided in the heating film protection circuit, it can be ensured that when the heating device fails and is out of control, the corresponding protection signal can be output in time according to the detection condition of the temperature detection circuit to protect the target equipment, thereby increasing the stability of the protection device.

[0071] The present application also provides a battery pack, referring to Figure 4 As shown, the battery pack includes: a battery cell 300, a positive terminal B+, a negative terminal B-, a positive output terminal P+, a negative output terminal P-, a heating film 100 and a heating control circuit 400, the heating film 100 is connected between the positive terminal B+ and the negative output terminal P-, the heating film 100 is in contact with the battery cell 300, the positive terminal B+ is connected to the positive output terminal P+, the negative terminal B- is connected to the negative output terminal P-, and a discharge switch tube can also be provided between the negative terminal B- and the negative output terminal P-. The heating control circuit 400 is provided between the heating film 100 and the negative output terminal P-, and the heating control circuit 400 is used to control the working state of the heating film 100. The battery pack also includes a heating film protection circuit as described above, the heating film protection circuit is connected to the heating control circuit 400, and the heating film protection circuit is in contact with the heating film 100. The heating film protection circuit is used to control the working state of the heating control circuit 400.

[0072] In this embodiment, the above-mentioned heating film protection circuit is integrated into the battery pack. Since the temperature protection circuit 20 and the isolation transmission circuit 30 are provided in the heating film protection circuit, it can be ensured that when a failure occurs and the heating control circuit 400 of the battery pack is uncontrolled, the corresponding protection signal is output in time according to the detection condition of the temperature detection circuit to protect the battery pack. The heating film protection circuit 400 can force the power supply circuit of the heating film 100 to be disconnected, thereby increasing the stability of the battery pack, improving the safety of the battery pack, and improving the user experience.

[0073] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0074] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0075] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0076] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A heating film protection circuit, characterized in that: The heating film protection circuit is applied to a battery pack, the battery pack comprises: a heating film and a heating control circuit, the heating film protection circuit is connected to the heating control circuit, and the heating film protection circuit is in contact with the heating film, and the heating film protection circuit comprises: A temperature detection circuit, in contact with the heating film, for detecting the temperature of the heating film and generating a temperature detection signal; A temperature protection circuit, connected to the temperature detection circuit, for receiving the temperature detection signal and generating an over-temperature protection signal when the voltage value of the temperature detection signal is greater than a preset temperature value; The isolation transmission circuit is arranged between the temperature protection circuit and the heating control circuit, and is used for receiving the over-temperature protection signal, isolating the over-temperature protection signal, and outputting it to the heating control circuit to control the working state of the heating control circuit.

2. The heating film protection circuit according to claim 1, characterized in that: The temperature detection circuit comprises: At least one thermistor, wherein a first end of the at least one thermistor is connected to the negative output end of the battery pack, a second end of the at least one thermistor is connected to the temperature protection circuit, and the at least one thermistor is in contact with the heating film.

3. The heating film protection circuit according to claim 2, characterized in that: The temperature protection circuit comprises: a first resistor, a second resistor, a third resistor and a first comparator; wherein, The first end of the first resistor is connected to the first power supply, the second end of the first resistor is connected to the non-inverting input terminal of the first comparator, the first end of the second resistor is connected to the first power supply, the second end of the second resistor is connected to the inverting input terminal of the first comparator, the first end of the third resistor is connected to the inverting input terminal of the first comparator, the second end of the third resistor is connected to the negative output terminal of the battery pack, and the output terminal of the first comparator is connected to the isolation transmission circuit.

4. The heating film protection circuit according to claim 1, characterized in that: The isolation transmission circuit comprises: At least one isolation unit, a first end of the at least one isolation unit is connected to the temperature protection circuit, and a second end of the at least one isolation unit is connected to the heating control circuit.

5. The heating film protection circuit according to claim 4, characterized in that: The at least one isolation unit comprises: At least one first diode, a first end of the at least one first diode is connected to the temperature protection circuit, and a second end of the at least one first diode is connected to the heating control circuit.

6. The heating film protection circuit according to any one of claims 1 to 5, characterized in that: The heating film protection circuit also includes: A feedback circuit is connected to the temperature protection circuit, and is used to receive the over-temperature protection signal, generate a temperature feedback signal according to the over-temperature protection signal, and output the temperature feedback signal to the temperature protection circuit.

7. The heating film protection circuit according to claim 6, characterized in that: The feedback circuit includes: a fourth resistor, a first end of the fourth resistor is connected to the output end of the temperature protection circuit, and a second end of the fourth resistor is connected to the input end of the temperature protection circuit.

8. The heating film protection circuit according to claim 3, characterized in that: The temperature protection circuit further includes: a first capacitor, a second capacitor and a third capacitor; wherein, The first end of the first capacitor is connected to the first end of the at least one thermistor, the second end of the first capacitor is connected to the second end of the at least one thermistor, the first end of the second capacitor is connected to the non-inverting input of the first comparator, the second end of the second capacitor is connected to the inverting input of the first comparator, the first end of the third capacitor is connected to the inverting input of the first comparator, and the second end of the third capacitor is connected to the negative output of the battery pack.

9. A protection device, characterized in that: The protection device comprises a heating film protection circuit as described in any one of claims 1-8.

10. A battery pack, characterized in that: The battery pack comprises: a battery cell, a positive terminal, a negative output terminal, a heating film and a heating control circuit, wherein the heating film is connected between the positive terminal and the negative output terminal, and the heating film is in contact with the battery cell; The heating control circuit is arranged between the heating film and the negative output terminal, and is used to control the working state of the heating film; The battery pack further comprises a heating film protection circuit as claimed in any one of claims 1 to 8, wherein the heating film protection circuit is connected to the heating control circuit, and the heating film protection circuit is in contact with the heating film; The heating film protection circuit is used to control the working state of the heating control circuit.

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