Protection circuit, heating control circuit, heating device and battery system

Abstract

The utility model relates to a protection circuit, a heating control circuit, a heating device and a battery system, a sampling unit is connected in series in a heating control loop of the heating control circuit, and heating current is obtained through sampling. And then a short-circuit locking unit detects whether the heating control loop is short-circuited based on the heating current, and locks a heating control switch of the heating control circuit to be in a turn-off state under the condition of short circuit, so that short-circuit protection of the heating control circuit is realized. According to the mode of realizing the short-circuit protection function through the hardware circuit, the short-circuit problem in the heating control process can be quickly responded, the reliability is high, normal operation can be recovered in time after the short-circuit fault is removed, and safe and stable operation of the battery system is facilitated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy, in particular to a protection circuit, a heating control circuit, a heating device and a battery system. BACKGROUND

[0002] With the rapid development of the new energy industry, lithium batteries have been widely used. Since using lithium batteries at low temperatures will cause irreversible damage to the battery cells, significantly reducing the service life of the battery, a heating film is usually provided inside the battery pack to improve the ambient temperature of the battery by controlling the heating of the heating film.

[0003] However, the current heating control of the heating film of the battery pack usually does not have corresponding protection measures, or only a fuse is connected in series in the circuit for protection. However, this simple protection by fuse not only may still cause battery short circuit due to the long response time of the fuse, on the other hand, the heating system will fail after the fuse is blown and cannot be used continuously. Therefore, it is necessary to propose corresponding protection measures for the heating control of the heating film of the battery pack. CONTENT OF THE INVENTION

[0004] Therefore, it is necessary to provide a protection circuit, a heating control circuit, a heating device and a battery system for the protection of the heating control of the heating film of the battery pack.

[0005] A protection circuit, the protection circuit comprising:

[0006] a sampling unit connected in series in a heating control loop of a heating control circuit, sampling a heating current;

[0007] a short circuit locking unit connected to the sampling unit, in the case of detecting a short circuit of the heating control loop based on the heating current, locking a heating control switch of the heating control circuit to an off state, realizing short circuit protection of the heating control circuit.

[0008] In one embodiment, the short circuit locking unit comprises a first locking switch and a second locking switch, the first locking switch having a control end, a first end and a second end, and the second locking switch also having a control end, a first end and a second end;

[0009] wherein the control end of the first locking switch is connected to the first end of the second locking switch, and the control end of the second locking switch is connected to the first end of the first locking switch, forming interlocking;

[0010] The control end of the first locking switch is also connected to the sampling unit, and the second end of the first locking switch is grounded. The control end of the second locking switch is also connected to the heating control circuit, and the second end of the second locking switch is connected to the control end of the heating control switch.

[0011] In one of the embodiments, the first locking switch is a triode or a field effect transistor.

[0012] In one of the embodiments, the short-circuit locking unit further comprises a first voltage dividing assembly, a first current limiting resistor, a first resistor and a second resistor.

[0013] The control end of the second locking switch is connected to the heating control circuit through the first voltage dividing assembly, the control end of the first locking switch is connected to the sampling unit through the first current limiting resistor, the first resistor is connected between the control end and the second end of the first locking switch, and the second resistor is connected between the control end and the second end of the second locking switch.

[0014] In one of the embodiments, the sampling unit comprises a sampling resistor, and the resistance value of the sampling resistor is set according to the short-circuit protection current value of the heating control circuit.

[0015] In one of the embodiments, the protection circuit further comprises:

[0016] A comparison unit connected between the sampling unit and the short-circuit locking unit, in the case of short-circuit of the heating control circuit, a locking signal is output to the short-circuit locking unit based on the heating current comparison, so that the short-circuit locking unit locks the heating control switch of the heating control circuit to the off state.

[0017] In one of the embodiments, the comparison unit comprises a comparator, a second voltage dividing assembly and a second current limiting resistor, and the comparator has a first input end, a second input end and an output end.

[0018] The first input end of the comparator is connected to the sampling unit through the second current limiting resistor, the second input end of the comparator is connected to the power supply end through the second voltage dividing assembly, and the output end of the comparator is connected to the short-circuit locking unit.

[0019] In one of the embodiments, the protection circuit further comprises a current detection unit connected to the sampling unit and a controller of the heating control circuit, for detecting the heating current and sending it to the controller.

[0020] In one of the embodiments, the protection circuit further comprises an anti-backflow diode, an anode of the anti-backflow diode being connected to the heating conduction circuit, and a cathode of the anti-backflow diode being connected to the control end of the heating control switch.

[0021] In one of the embodiments, a heating control circuit is provided, comprising a controller, a signal output circuit, a heating conduction circuit, a heating control switch, and the protection circuit as described above, the controller being connected to the signal output circuit, the signal output circuit being connected to the heating conduction circuit, the heating conduction circuit being connected to a power supply end, the heating conduction circuit further being connected to the control end of the heating control switch through the protection circuit, a first end and a second end of the heating control switch being connected in series to a heating element of a heating device, a positive end and a negative end of a battery pack to form a heating control loop, and the protection circuit further being connected in series to the heating control loop.

[0022] In one of the embodiments, a heating device is provided, comprising a heating element and the heating control circuit as described above.

[0023] In one of the embodiments, a battery system is provided, comprising a battery pack and the heating device as described above.

[0024] The protection circuit, the heating control circuit, the heating device, and the battery system as described above, by connecting the sampling unit in series to the heating control loop of the heating control circuit, sample the heating current. Then, by the short-circuit locking unit detecting whether a short circuit occurs in the heating control loop based on the heating current, and locking the heating control switch of the heating control circuit to the off state in the case of a short circuit, the short-circuit protection of the heating control circuit is realized. The above-mentioned way of realizing the short-circuit protection function through the hardware circuit can quickly respond to the short-circuit problem of the heating control process, has high reliability, and can resume normal operation in time after the short-circuit fault is removed, which is conducive to the safe and stable operation of the battery system. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the drawings needed to be used in the description of the embodiments of the present application or the related art will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other related drawings can be obtained by those skilled in the art without any creative effort.

[0026] Figure 1 It is a circuit schematic diagram of the heating control circuit in one of the embodiments;

[0027] Figure 2 It is a circuit schematic diagram of the heating control circuit in another embodiment;

[0028] Figure 3 Circuit schematic diagram of the heating control circuit in yet another embodiment.

[0029] Figure 4 Circuit schematic diagram of the heating control circuit in yet another embodiment. DETAILED DESCRIPTION

[0030] In order to make the purposes, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and not intended to limit the present application.

[0031] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing specific embodiments only and is not intended to be limiting of the present application.

[0032] It can be understood that the terms "first", "second" and the like used in the description of the present application are used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish the first element from the second element. For example, without departing from the scope of the present application, the first resistor can be referred to as the second resistor, and similarly, the second resistor can be referred to as the first resistor. The first resistor and the second resistor are both resistors, but they are not the same resistor.

[0033] It can be understood that "connection" in the following embodiments, if the circuits, modules, units and the like connected to each other have the transmission of electrical signals or data, should be understood as "electrically connected", "communicatively connected" and the like.

[0034] As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. It should also be understood that the term "comprising" or "including" or "having" and the like, specifies the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but does not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

[0035] As described in the background, with the rapid development of the new energy industry, lithium batteries have been widely used. Since the use of lithium batteries at low temperature will cause irreversible damage to the battery cell, greatly reducing the service life of the battery, a heating film is usually provided inside the battery pack to improve the ambient temperature of the battery by controlling the heating of the heating film. However, the current heating control of the battery pack heating film usually does not have corresponding protection measures, or only a fuse is connected in series in the circuit for protection. However, this simple protection by the fuse not only may still cause a short circuit of the battery due to the relatively long melting response time of the fuse, but on the other hand, the heating system will fail after the fuse is melted and cannot be used continuously. Therefore, it is urgent to propose corresponding protection measures for the heating control of the battery pack heating film.

[0036] Based on this, the application realizes the short circuit protection function of the heating control circuit through a hardware circuit, can quickly respond to the short circuit problem of the heating control process, has high reliability, and is conducive to the safe and stable operation of the battery system.

[0037] The protection circuit provided by the embodiments of the application can be applied to a heating control circuit as shown in Figure 1 The heating control circuit at least includes a controller (not shown in the figure), a signal output circuit 110, a heating conduction circuit 120, and a heating control switch 130. The signal output circuit 110 is connected to the heating conduction circuit 120, the heating conduction circuit 120 is connected to a power supply end 12V6, and the heating conduction circuit 120 is also connected to the control end of the heating control switch 130. The first end and the second end of the heating control switch 130 are connected in series with the heating element of the heating device, the positive end B+ of the battery pack, and the ground end GND to form a heating control loop. The controller can control the on-off of the heating control switch 130 by outputting a heating control signal En_Heat, thereby controlling the on-off of the heating control loop, that is, controlling whether the heating element works or not.

[0038] In an exemplary embodiment, as shown in Figure 2 A protection circuit is provided, which includes a sampling unit 151 connected in series in the heating control loop of the heating control circuit, and the heating current is sampled; a short circuit locking unit 152 connected to the sampling unit 151, which locks the heating control switch 130 of the heating control circuit to an off state when detecting that the heating control loop has a short circuit based on the heating current, thereby realizing short circuit protection of the heating control circuit.

[0039] The heating control loop is a loop for controlling the power supply connection of the heating element, as shown in Figure 2The heating control loop is formed from the positive terminal B+ of the battery pack, through the heating element, the first terminal and the second terminal of the heating control switch 130, to the ground terminal GND. When the heating control switch 130 is turned on, the heating control loop is turned on, and the heating element is powered by the battery pack; when the heating control switch 130 is turned off, the heating control loop is turned off, and the heating element stops being powered.

[0040] Specifically, the sampling unit 151 is connected in series in the heating control loop to sample the heating current during the operation of the heating element. It can be understood that the position of the sampling unit 151 connected in series in the heating control loop is not unique, and can be arranged between the heating element and the heating control switch 130, or arranged between the heating control switch 130 and the ground terminal GND, as long as the heating current can be sampled.

[0041] Exemplarily, the sampling unit 151 can be implemented by a sampling resistor. The sampling resistor can be one resistor or a plurality of resistors connected in series, and then the current value is obtained by collecting the voltage value across the sampling resistor.

[0042] Further, the short-circuit locking unit 152 can be connected across the sampling resistor to sample the heating current according to the voltage difference across the sampling resistor and detect whether the heating control loop is short-circuited in time. It can be understood that when the heating control loop is not short-circuited, the voltage difference across the sampling resistor will be small. When the heating control loop is short-circuited, the heating current will increase significantly, and the voltage difference across the sampling resistor will also increase significantly, so that whether the heating control loop is short-circuited can be determined based on this. Further, when it is detected that the heating control loop is short-circuited, the short-circuit locking unit 152 can also lock the heating control switch 130 of the heating control circuit to the off state to achieve short-circuit protection of the heating control circuit.

[0043] Exemplarily, the short-circuit locking unit 152 can include a switching circuit composed of a switching device such as a transistor, i.e. the switching device controls the on-off of the heating control switch 130 to lock it to the off state. When the switching device is closed, the short-circuit locking unit 152 is equivalent to a short-circuit state, the heating control switch 130 is grounded through the short-circuit locking unit 152, and is locked to the off state, the heating control loop is disconnected, and the heating element stops being powered; when the switching device is open, the short-circuit locking unit 152 is equivalent to an open circuit state, the heating control switch 130 is normally controlled by the heating control signal to realize on-off control, and the working state of the heating control loop and the heating element is controlled based on the heating control signal.

[0044] Exemplarily, the short-circuit locking unit 152 can be directly realized by connecting the control end and the first end of the transistor across the sampling resistor to determine whether the short circuit occurs in the heating control loop according to the voltage difference across the sampling resistor. That is, in the case that the short circuit occurs in the heating control loop and the voltage difference across the sampling resistor increases significantly, the voltage difference between the control end and the first end of the transistor will increase significantly. When the voltage difference between the control end and the first end of the transistor rises to turn on the transistor, the heating control switch 130 can be locked in the off state, and then the heating control loop is disconnected, and the heating element stops power supply.

[0045] The above protection circuit can sample the heating current by connecting the sampling unit in series in the heating control loop of the heating control circuit. Then, the short-circuit locking unit can detect whether the short circuit occurs in the heating control loop based on the heating current, and lock the heating control switch of the heating control circuit in the off state in the case that the short circuit occurs, to realize the short-circuit protection of the heating control circuit. The above method of realizing the short-circuit protection function by the hardware circuit can quickly respond to the short-circuit problem in the heating control process, has high reliability, and can restore normal operation in time after the short-circuit fault is removed, which is beneficial to the safe and stable operation of the battery system.

[0046] In one of the embodiments, referring to Figure 2 The sampling unit 151 includes a sampling resistor R18, and the resistance value of the sampling resistor R18 is set according to the short-circuit protection current value of the heating control loop.

[0047] The short-circuit protection current value of the heating control loop represents the value of the corresponding heating current when the short-circuit protection is implemented, which can be set according to the actual technical requirements. Correspondingly, the resistance value of the sampling resistor R18 can be set according to the short-circuit protection current value of the heating control loop, so that when the heating current of the heating control loop reaches the above short-circuit protection current value, the short-circuit locking unit 152 enters the short-circuit state due to the voltage difference across the sampling resistor, so that the heating control switch 130 is grounded through the short-circuit locking unit 152, locked in the off state, the heating control loop is disconnected, and the heating element stops power supply.

[0048] In one of the exemplary embodiments, the short-circuit locking unit includes a first locking switch and a second locking switch, the first locking switch has a control end, a first end and a second end, and the second locking switch also has a control end, a first end and a second end; wherein the control end of the first locking switch is connected with the first end of the second locking switch, and the control end of the second locking switch is connected with the first end of the first locking switch, forming interlocking; the control end of the first locking switch is also connected with the sampling unit, the second end of the first locking switch is grounded, the control end of the second locking switch is also connected with the heating conduction circuit of the heating control circuit, and the second end of the second locking switch is connected with the control end of the heating control switch.

[0049] In particular, please continue to refer to Figure 2 , the first lock switch is a switch tube Q5, and the second lock switch is a switch tube Q3. The control end of the switch tube Q5 is connected with the first end of the switch tube Q3, and the control end of the switch tube Q3 is connected with the first end of the switch tube Q5, forming an interlocking structure. The control end of the switch tube Q5 is connected with one end of a sampling resistor R18, and the second end of the switch tube Q5 is connected with the other end (ground end) of the sampling resistor R18, so as to realize the voltage difference sampling of the sampling resistor R18. The second end of the switch tube Q3 is connected with the control end of the heating control switch 130.

[0050] In the case of short circuit of the heating control circuit, the switch tube Q5 is turned on due to the voltage difference rise of the sampling resistor R18, the control end of the switch tube Q3 is grounded through the switch tube Q5, the switch tube Q3 is turned on, the switch tube Q3 and the switch tube Q5 form interlocking, the control end of the heating control switch 130 is grounded through the switch tube Q3 and the switch tube Q5, and the heating control switch 130 is locked in the off state, the heating control circuit is disconnected, and the heating element stops power supply.

[0051] In addition, the control end of the switch tube Q3 is also connected with the heating conduction circuit of the heating control circuit, so that in the case that the heating control circuit does not occur short circuit and the switch tube Q5 is not turned on, the control end of the switch tube Q3 obtains high level through the heating conduction circuit, so that the switch tube Q3 remains in the off state, and the short circuit lock unit 152 is in the open circuit state.

[0052] In an exemplary embodiment, as shown in Figure 2 , the first lock switch can be a triode. In another embodiment, as shown in Figure 3 , the first lock switch can also be a field effect tube, which can be an Insulated Gate Bipolar Transistor (IGBT).

[0053] In an exemplary embodiment, please refer to Figure 2 or Figure 3 , the short circuit lock unit 152 further includes a first voltage dividing assembly, a first current limiting resistor, a first resistor and a second resistor. The control end of the second lock switch is connected with the heating conduction circuit through the first voltage dividing assembly, the control end of the first lock switch is connected with the sampling unit through the first current limiting resistor, the first resistor is connected between the control end and the second end of the first lock switch, and the second resistor is connected between the control end and the second end of the second lock switch.

[0054] The first voltage divider component is composed of the resistor R8 and the resistor R13, the first current limiting resistor is the resistor R11, the first resistor is the resistor R14, and the second resistor is the resistor R4. The control end of the switch tube Q3 is connected to the common end of the resistors R8 and R13 after voltage division, the other end of the resistor R8 is connected to the heating conduction circuit, the other end of the resistor R13 is grounded, the control end of the switch tube Q5 is connected to one end of the sampling resistor R18 through the resistor R11, the resistor R14 is connected between the control end and the second end of the switch tube Q5, and the resistor R4 is connected between the control end and the second end of the switch tube Q3.

[0055] In one exemplary embodiment, please refer to Figure 4 The protection circuit further comprises a comparison unit 153 connected between the sampling unit 151 and the short circuit locking unit 152. In the case of a short circuit in the heating control circuit, a locking signal is output to the short circuit locking unit 152 based on the heating current comparison, so that the short circuit locking unit 152 locks the heating control switch 130 of the heating control circuit to the off state.

[0056] It can be understood that the protection circuit can also be connected between the two ends of the sampling resistor through a comparison device, and the comparison device is used to determine whether a short circuit occurs in the heating control circuit.

[0057] Specifically, in the case of determining a short circuit according to the voltage difference between the two ends of the sampling resistor, the comparison unit 153 outputs a locking signal to the switching device of the short circuit locking unit 152, so that the switching device is turned on to lock the heating control switch 130 to the off state, and then the heating control circuit is disconnected, and the heating element stops power supply.

[0058] In the embodiment, the comparison device is used to determine the voltage difference between the two ends of the sampling resistor, and then output a locking signal to control the on-off state of the short circuit locking unit 152, so that the isolation of the short circuit fault can be realized more stably and reliably, and the safety of the battery system is ensured.

[0059] In one exemplary embodiment, please continue to refer to Figure 4 The comparison unit 153 comprises a comparator U1, a second voltage divider component and a second current limiting resistor. The comparator U1 has a first input end, a second input end and an output end. The first input end of the comparator U1 is connected to the sampling unit 151 through the second current limiting resistor, the second input end of the comparator U1 is connected to the power supply end VCC through the second voltage divider component, and the output end of the comparator U1 is connected to the short circuit locking unit 152.

[0060] The second voltage dividing assembly is composed of the resistor R1 and the resistor R6, and the second current limiting resistor is the resistor R2. The first input terminal +IN of the comparator U1 is connected to one end of the sampling resistor R18 through the resistor R2, the second input terminal -IN of the comparator U1 is connected to the common terminal of the resistors R1 and R6 after voltage division, the other end of the resistor R1 is connected to the power supply terminal VCC, and the other end of the resistor R6 is connected to the ground. The output terminal OUT of the comparator U1 is connected to the control terminal of the switch tube Q5 through the resistor R11.

[0061] Specifically, the second input terminal -IN of the comparator U1 is connected to the reference voltage Vref after voltage division by the second voltage dividing assembly. The reference voltage Vref can be slightly less than the voltage value of the short-circuit voltage threshold (the voltage difference between the two ends of the sampling resistor R18 when the heating current is the short-circuit protection current value) by setting the resistance values of the resistors R1 and R6.

[0062] Further, the comparator U1 outputs a locking signal to the control terminal of the switch tube Q5 to make the switch tube Q5 and the switch tube Q3 interlock and conduct when it is determined that the short circuit occurs according to the voltage difference between the two ends of the sampling resistor, so as to lock the heating control switch 130 to the off state, and further disconnect the heating control circuit to stop the power supply of the heating element.

[0063] In an exemplary embodiment, please continue to refer to Figure 4 The protection circuit further comprises a current detection unit 154 connected to the sampling unit 151 and the controller of the heating control circuit, for detecting the heating current and sending it to the controller.

[0064] Specifically, the current detection unit 154 comprises the resistor R17 and the capacitor C1. One end of the resistor R17 is connected to one end of the sampling resistor R18, the other end of the resistor R17 is connected to the ADC port of the controller, and the other end of the resistor R17 is further connected to the ground through the capacitor C1.

[0065] It can be understood that the controller can obtain the heating current in the working process of the heating element through the current detection unit 154, and further realize various functions such as overcurrent protection, heating film fault detection and real-time monitoring of heating power consumption, and can identify whether the heating control circuit is abnormal based on the monitoring of the above data. The controller can realize the various functions described above through its corresponding ADC function or other voltage acquisition or comparison functions it has, which will not be described here.

[0066] In an exemplary embodiment, please continue to refer to Figure 4 The protection circuit further comprises an anti-backflow diode D1, the anode of the anti-backflow diode D1 is connected to the heating conduction circuit 120, and the cathode of the anti-backflow diode D1 is connected to the control terminal of the heating control switch 130. It can be understood that the anti-backflow diode D1 can prevent the short circuit of the heating control circuit from impacting the control side.

[0067] In one exemplary embodiment, please continue to refer to Figure 4 , a heating control circuit is provided, including a controller, a signal output circuit 110, a heating conduction circuit 120, a heating control switch 130 and a protection circuit, the controller is connected to the signal output circuit 110, the signal output circuit 110 is connected to the heating conduction circuit 120, the heating conduction circuit 120 is connected to the power supply end 12V6, the heating conduction circuit 120 is also connected to the control end of the heating control switch 130 through the protection circuit, the first end and the second end of the heating control switch 130 are connected in series with the heating element of the heating device, the positive end B+ and the negative end of the battery pack to form a heating control loop, and the protection circuit is also connected in series in the heating control loop.

[0068] Among them, the signal output circuit 110 includes a resistor R10, a resistor R16, a switch tube Q7 and a resistor R7, the heating conduction circuit 120 includes a resistor R5, a switch tube Q2 and a resistor R3, the heating control switch 130 is a switch tube Q6, and the heating control circuit further includes a resistor R9 and a resistor R15. The protection circuit includes a sampling resistor R18, a switch tube Q5, a switch tube Q3, a resistor R8, a resistor R13, a resistor R11, a resistor R14, a resistor R4, a comparator U1, a resistor R1, a resistor R6, a resistor R2, a resistor R17, a capacitor C1 and an anti-flow diode D1.

[0069] Specifically, the control end of the switch tube Q7 is connected with the common end of the resistors R10 and R16 after voltage division, the other end of the resistor R10 is connected with the heating control signal En_Heat obtained by the controller, the other end of the resistor R16 is grounded, the first end of the switch tube Q7 is connected with the control end of the switch tube Q2 through the resistor R7, the second end of the switch tube Q7 is grounded, the first end of the switch tube Q2 is connected with the power supply end 12V6, the resistor R5 is connected between the control end and the first end of the switch tube Q2, and the second end of the switch tube Q2 is connected with the anode of the anti-flow diode D1 through the resistor R3. The control end of the switch tube Q3 is connected with the common end of the resistors R8 and R13 after voltage division, the other end of the resistor R8 is connected with the anode of the anti-flow diode D1, and the other end of the resistor R13 is grounded. The control end of the switch tube Q5 is connected with the first end of the switch tube Q3, and the control end of the switch tube Q3 is connected with the first end of the switch tube Q5, forming an interlocking structure. The control end of the switch tube Q5 is connected with the output end OUT of the comparator U1 through the resistor R11, the resistor R14 is connected between the control end and the second end of the switch tube Q5, and the resistor R4 is connected between the control end and the second end of the switch tube Q3. The first input end +IN of the comparator U1 is connected with one end of the sampling resistor R18 through the resistor R2, and the second input end -IN of the comparator U1 is connected with the common end of the resistors R1 and R6 after voltage division, the other end of the resistor R1 is connected with the power supply end VCC, and the other end of the resistor R6 is grounded. The control end of the switch tube Q6 is connected with the common end of the resistors R9 and R15 after voltage division, the other end of the resistor R9 is connected with the second end of the switch tube Q3 and the cathode of the anti-flow diode D1, the other end of the resistor R15 is grounded, the first end of the switch tube Q6 is connected with the positive electrode end B+ of the battery pack through the heating element, and the second end of the switch tube Q6 is grounded through the sampling resistor R18. One end of the resistor R17 is connected with one end of the sampling resistor R18, the other end of the resistor R17 is connected with the ADC port of the controller, and the other end of the resistor R17 is also grounded through the capacitor C1.

[0070] It can be understood that the controller outputs the heating control signal En_Heat to control the opening and closing of the switch tube Q7, and further controls the opening and closing of the switch tube Q2, and further controls whether the power supply end 12V6 supplies power to the control end of the switch tube Q6, and further controls the opening and closing of the heating control loop, that is, controls whether the heating element works. Further, the comparator U1 outputs a locking signal to the control end of the switch tube Q5 to make the switch tube Q5 and the switch tube Q3 interlock conduction when it is determined that a short circuit occurs according to the voltage difference between the two ends of the sampling resistor R18, so as to lock the switch tube Q6 in the off state, and further disconnect the heating control loop and stop the power supply of the heating element.

[0071] Exemplarily, the switch tube Q2, the switch tube Q3, the switch tube Q5 and the switch tube Q7 can be realized by triodes, the switch tube Q5 can also be realized by a field effect tube, and the switch tube Q6 is realized by a field effect tube. In addition, the switch tube Q2 and the switch tube Q7 can be triodes of opposite types, the switch tube Q2 can be low-level on, and the switch tube Q7 is high-level on. Similarly, the switch tube Q3 and the switch tube Q5 can also be triodes of opposite types.

[0072] In the embodiment, the heating current is sampled by connecting the sampling unit in series in the heating control loop of the heating control circuit. The short circuit locking unit detects whether the short circuit occurs in the heating control loop based on the heating current, and locks the heating control switch of the heating control circuit to the off state in the case of short circuit, so as to realize the short circuit protection of the heating control circuit. The short circuit protection function realized by the hardware circuit can quickly respond to the short circuit problem of the heating control process, has high reliability, and can restore normal operation in time after the short circuit fault is removed, which is beneficial to the safe and stable operation of the battery system.

[0073] In an exemplary embodiment, a heating device is provided, comprising a heating element and a heating control circuit as described in any of the above embodiments.

[0074] In an exemplary embodiment, a battery system is provided, comprising a battery pack and a heating device as described in any of the above embodiments.

[0075] It can be understood that the implementation solutions of the above-mentioned heating device and battery system are similar to the implementation solutions of the above-mentioned protection circuit, so the specific limitations in one or more heating device and battery system embodiments provided above can refer to the limitations of the protection circuit described above, and will not be described here.

[0076] The technical features of the above-mentioned embodiments can be combined in any way. In order to make the description simple, all possible combinations of the technical features in the above-mentioned embodiments are not described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the description.

[0077] The above-mentioned embodiments only express several implementation manners of the present application, the description is more specific and detailed, but it should not be understood as the limitation of the scope of the utility model patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A protection circuit, characterized by, The protection circuit comprises: a sampling unit connected in series in a heating control loop of the heating control circuit, and sampling a heating current; a short circuit locking unit connected to the sampling unit, and locking a heating control switch of the heating control circuit to an off state in a case where a short circuit of the heating control loop is detected based on the heating current, so as to realize short circuit protection of the heating control circuit; the short circuit locking unit comprises a first locking switch and a second locking switch, the first locking switch has a control end, a first end and a second end, and the second locking switch also has a control end, a first end and a second end; wherein the control end of the first locking switch is connected to the first end of the second locking switch, and the control end of the second locking switch is connected to the first end of the first locking switch, forming interlocking; the control end of the first locking switch is also connected to the sampling unit, the second end of the first locking switch is grounded, the control end of the second locking switch is also connected to a heating conduction circuit of the heating control circuit, and the second end of the second locking switch is connected to the control end of the heating control switch.

2. The protection circuit of claim 1, wherein, The first locking switch is a triode or a field effect transistor.

3. The protection circuit of claim 1, wherein, The short circuit locking unit further comprises a first voltage dividing assembly, a first current limiting resistor, a first resistor and a second resistor; the control end of the second locking switch is connected to the heating conduction circuit through the first voltage dividing assembly, the control end of the first locking switch is connected to the sampling unit through the first current limiting resistor, the first resistor is connected between the control end and the second end of the first locking switch, and the second resistor is connected between the control end and the second end of the second locking switch.

4. The protection circuit of claim 1, wherein, The sampling unit comprises a sampling resistor, and a resistance value of the sampling resistor is set according to a short circuit protection current value of the heating control loop.

5. The protection circuit of claim 1, wherein, The protection circuit further comprises: a comparison unit connected between the sampling unit and the short circuit locking unit, and outputting a locking signal to the short circuit locking unit based on the heating current in a case where a short circuit of the heating control loop occurs, so as to make the short circuit locking unit lock the heating control switch of the heating control circuit to the off state.

6. The protection circuit of claim 5, wherein, The comparison unit comprises a comparator, a second voltage dividing assembly and a second current limiting resistor, and the comparator has a first input end, a second input end and an output end; the first input end of the comparator is connected to the sampling unit through the second current limiting resistor, the second input end of the comparator is connected to a power supply end through the second voltage dividing assembly, and the output end of the comparator is connected to the short circuit locking unit.

7. The protection circuit according to any one of claims 1 to 6, characterized in that, The protection circuit further comprises a current detection unit connected to the sampling unit and a controller of the heating control circuit, and configured to detect the heating current and send the heating current to the controller.

8. The protection circuit according to any one of claims 1 to 6, characterized in that The protection circuit further comprises an anti-backflow diode, an anode of the anti-backflow diode is connected to the heating conduction circuit, and a cathode of the anti-backflow diode is connected to the control end of the heating control switch.

9. A heating control circuit, characterized by The protection circuit comprises a controller, a signal output circuit, a heating conduction circuit, a heating control switch, and the protection circuit as claimed in any one of claims 1 to 8, the controller is connected to the signal output circuit, the signal output circuit is connected to the heating conduction circuit, the heating conduction circuit is connected to a power supply end, the heating conduction circuit is further connected to a control end of the heating control switch through the protection circuit, a first end and a second end of the heating control switch are connected in series with a heating element of a heating device, a positive end and a negative end of a battery pack to form a heating control loop, and the protection circuit is further connected in series in the heating control loop.

10. A heating device, characterized by The heating control circuit comprises a heating element and the heating control circuit as claimed in claim 9.

11. A battery system characterized by, The heating device comprises a battery pack and the heating device as claimed in claim 10.

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