Battery heating control circuit and battery heating control method of battery system

Abstract

The present invention discloses a battery heating control circuit and a battery heating control method for a battery system, wherein the circuit comprises a battery heating branch, wherein the battery heating branch comprises a heating relay, a first resistor and a heater connected in series in sequence, and semiconductor switches are connected in parallel at both ends of the heating relay; a heating control module, wherein the first output end of the heating control module is connected to the control end of the semiconductor switch, and the heating control module is used to send a high-frequency square wave signal to the semiconductor switch, control the semiconductor switch to be turned on, and detect whether the heater on the battery heating branch has a fault; if it is determined that the heater has no fault, the heating relay is controlled to be turned on and the semiconductor switch is controlled to be turned off. In the battery heating control circuit of the present invention, no arc is generated when the relay is closed, and on the basis of no arc generation, the switch contacts will not stick, thereby improving the reliability of the battery heating control circuit, effectively extending the use of the relay, and not requiring frequent replacement to increase maintenance costs.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a battery heating control circuit and a battery heating control method of a battery system. Background Art

[0002] In the prior art, since the power battery of new energy vehicles has poor performance at low temperatures, it is necessary to increase the battery temperature at low temperatures. The current commonly used battery heating method is heating by a heating system inside the battery pack. The heating system includes a battery heating control circuit installed inside the battery pack. The circuit includes a relay connected to one end of the battery, a fuse, a heating element (such as PTC, heating film) and a wiring harness. Among them, whether the circuit of the heating system is conductive or not is controlled by the switch of the relay; the fuse plays a protective role to prevent excessive current from burning out the circuit and components when the circuit fails; the heating element is used to heat the battery.

[0003] However, when the relay contacts are closed or disconnected under high voltage, an arc will be generated, which will damage the contacts and even cause the contacts to stick. When the circuit of the heating system fails, the high current will cause the relay contacts to stick and be unable to disconnect, affecting the safety of the battery pack and the entire vehicle. On the other hand, the fuse's breaking time is related to the current size. The larger the current, the faster the breaking time. If the current is too large, the circuit and the device will burn out before the fuse blows; if the current is small (still in the overcurrent range), the fuse breaking time is slow, and the circuit and the device will continue to work before the fuse blows, which will also cause damage to the circuit and the device. It can be seen that the protection effect of the fuse in the event of a fault is not obvious, and the reliability and safety of the battery heating control circuit are low. Summary of the invention

[0004] The embodiments of the present invention provide a battery heating control circuit and a battery heating control method of a battery system to solve the problem of low reliability of the existing battery heating control circuit.

[0005] Based on the above purpose, in one embodiment, a battery heating control circuit of a battery system is provided, the battery heating control circuit comprising:

[0006] A battery heating branch, the battery heating branch comprising a heating relay, a first resistor R2 and a heater connected in series in sequence, and a semiconductor switch Q1 is connected in parallel at both ends of the heating relay;

[0007] A heating control module, wherein the first output end of the heating control module is connected to the control end of the semiconductor switch, and the heating control module is used to send a high-frequency square wave signal to the semiconductor switch Q1 to control the semiconductor switch Q1 to be turned on, and detect whether the heater on the battery heating branch has a fault; if it is determined that the heater has no fault, the heating relay is controlled to be turned on, and the semiconductor switch Q1 is controlled to be turned off.

[0008] In one embodiment, the battery heating control circuit further includes:

[0009] A current sampling module, wherein the input end of the current sampling module is used to collect the branch current of the battery heating branch after the semiconductor switch Q1 is turned on; the output end of the current sampling module is connected to the input end of the heating control module, and is used to send the branch current of the battery heating branch to the heating control module, and the heating control module is used to determine whether the heater is faulty based on the branch current.

[0010] In one embodiment, the current sampling module is a current sensor or a shunt, and a sampling point of the current sampling module is arranged between the output end of the first resistor R2 and the input end of the heater.

[0011] In one embodiment, the second output end of the heating control module is connected to a relay coil branch, in which the coil of the heating relay is connected in series; the heating control module is used to control the coil of the heating relay to be turned on after determining that the heater is not faulty, so as to turn on the heating relay.

[0012] In one embodiment, the battery heating control circuit further includes:

[0013] A battery power supply branch, the battery power supply branch comprising: a total positive contactor K1, a total negative contactor K2, and a second resistor R1, wherein the input end of the total positive contactor K1 is connected to the positive electrode of the battery, the output end of the total negative contactor K2 is connected to the load, the input end of the total negative contactor K2 is connected to the load, and the output end of the total negative contactor K2 is connected to the negative electrode of the battery through the second resistor R1.

[0014] In one embodiment, the third output end of the heating control module is connected to the control end of the total positive contactor K1, and the fourth output end of the heating control module is connected to the control end of the total negative contactor K2; the heating control module is used to control the total positive contactor K1 and the total negative contactor K2 to turn on the battery power supply branch after controlling the battery heating branch to disconnect.

[0015] In one embodiment, a battery heating control method for a battery system is provided, wherein the battery heating control method is applied to the battery heating control circuit, and the battery heating control method includes:

[0016] Sending a high-frequency square wave signal to the semiconductor switch Q1 to control the semiconductor switch Q1 to be turned on, and detecting whether the heater has a fault;

[0017] If it is determined that the heater has no fault, the heating relay is controlled to be turned on and the semiconductor switch Q1 is controlled to be turned off; if it is determined that the heater has a fault, the semiconductor switch Q1 is controlled to be turned off and a fault alarm signal is generated;

[0018] When it is detected that the temperature of the battery is within a normal temperature range, the heating control module is controlled to be non-conductive.

[0019] In one embodiment, detecting whether the heater is faulty includes:

[0020] Control the current sampling module to collect the branch current output from the output end of the first resistor R2; calculate the voltage signal waveform of the heater according to the branch current, combined with the terminal voltage of the battery and the resistance value of the first resistor R2;

[0021] A reference voltage signal waveform diagram of the heater in a non-fault state is obtained, the voltage signal waveform diagram is compared with the reference voltage signal waveform diagram to obtain a comparison result of the reference voltage signal, and whether the heater is faulty is determined according to the comparison result.

[0022] In one embodiment, comparing the voltage signal waveform with the reference voltage signal waveform to obtain a comparison result of the reference voltage signal, and determining whether the heater is faulty according to the comparison result includes:

[0023] Extracting N first characteristic graphs of the voltage signal waveform graph and N second characteristic graphs of the reference voltage signal waveform graph, where N>2;

[0024] Calculate the similarities between the N first feature graphs and the N second feature graphs to obtain N similarities; based on the comparison results of the N similarities with a preset similarity threshold, select the number of similarities n greater than the similarity threshold, n≤N, as the comparison result of the reference voltage signal;

[0025] When the similarity number n is greater than a preset similarity number threshold, it is confirmed that the heater has no fault; when the similarity number n is not greater than the preset similarity number threshold, it is confirmed that the heater has a fault.

[0026] In one embodiment, controlling the heating control module to be non-conductive includes:

[0027] The semiconductor switch Q1 is first controlled to be turned on, and then the heating relay is controlled to be turned off; after the heating relay is turned off, the semiconductor switch Q1 is controlled to be turned off.

[0028] The above-mentioned battery heating control circuit and battery heating control method are connected in parallel at both ends of the relay K3 through the semiconductor switch Q1, and are turned on before the relay K3 is closed, so that the current first flows through the branch where the semiconductor switch Q1 is located, and there is no pressure difference across the relay K3; only after the relay K3 is closed, the current will pass through the branch where the relay K3 is located, so that the heater works to generate heat, so no arc is generated when the relay K3 is closed, and on the basis of no arc generation, the switch contacts will not stick, thereby improving the reliability of the battery heating control circuit, and can effectively extend the use of the relay without frequent replacement to increase maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative labor.

[0030] Figure 1 is a schematic diagram of a battery heating control circuit in one embodiment of the present invention;

[0031] Figure 2 is a circuit connection diagram of a heating control module in one embodiment of the present invention;

[0032] Figure 3 is a flow chart of a battery heating control method of a battery system in one embodiment of the present invention;

[0033] Figure 4 is a flow chart of a method for detecting whether a heater is faulty in one embodiment of the present invention;

[0034] Figure 5 It is a flow chart of the comparison result of obtaining the reference voltage signal by comparing the voltage signal waveform diagram and the reference voltage signal waveform diagram in one embodiment of the present invention;

[0035] Figure 6 It is another schematic diagram of a battery heating control circuit in an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] It should be understood that the present invention can be implemented in different forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, providing these embodiments will make the disclosure thorough and complete and fully convey the scope of the present invention to those skilled in the art. In the accompanying drawings, the sizes and relative sizes of layers and regions may be exaggerated for clarity. The same reference numerals throughout represent the same elements.

[0038] It should be understood that when an element or layer is referred to as being "on, adjacent to, connected to or coupled to other elements or layers, it may be directly on, adjacent to, connected to or coupled to other elements or layers, or there may be intervening elements or layers. In contrast, when an element is referred to as being "directly on, directly adjacent to, directly connected to or directly coupled to other elements or layers, there may be no intervening elements or layers. It should be understood that, although the terms first, second, third, etc. may be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present invention, the first element, component, region, layer or part discussed below may be represented as a second element, component, region, layer or part.

[0039] Spatially relative terms such as "under," "beneath," "below," "under," "above," "above," and the like may be used herein for ease of description to describe the relationship of an element or feature shown in the figures to other elements or features. It should be understood that the spatially relative terms are intended to include different orientations of the device in use and operation in addition to the orientations shown in the figures. For example, if the device in the accompanying drawings is flipped, then the elements or features described as "under other elements" or "under" or "under" will be oriented as "above" the other elements or features. Thus, the exemplary terms "under" and "under" may include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or other orientations) and the spatial descriptors used herein are interpreted accordingly.

[0040] The purpose of the terms used herein is only to describe specific embodiments and is not intended to be limiting of the present invention. When used herein, the singular forms "one", "an" and "said / the" are also intended to include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "consisting of" and / or "comprising", when used in this specification, determine the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups. When used herein, the term "and / or" includes any and all combinations of the relevant listed items.

[0041] In order to fully understand the present invention, detailed structures and steps will be presented in the following description to illustrate the technical solutions proposed by the present invention. The preferred embodiments of the present invention are described in detail below, but in addition to these detailed descriptions, the present invention may also have other implementations.

[0042] In one embodiment, if Figure 1 and Figure 2 As shown, a battery heating control circuit of a battery system is provided, and the battery heating control circuit comprises:

[0043] A battery heating branch, the battery heating branch comprising a heating relay, a first resistor R2 and a heater connected in series in sequence, and a semiconductor switch Q1 is connected in parallel at both ends of the heating relay;

[0044] A heating control module, wherein the first output terminal 6 of the heating control module (i.e., MCU) is connected to the control terminal of the semiconductor switch, and the heating control module is used to send a high-frequency square wave signal to the semiconductor switch Q1 to control the semiconductor switch Q1 to be turned on, and detect whether the heater on the battery heating branch has a fault; if it is determined that the heater has no fault, the heating relay is controlled to be turned on, and the semiconductor switch Q1 is controlled to be turned off.

[0045] The semiconductor switch Q1 is preferably an IGBT tube.

[0046] The working process of the above battery heating control circuit is:

[0047] The heating control module sends a high-frequency square wave signal to the semiconductor switch Q1 to control the semiconductor switch Q1 to turn on, and then detects whether the heater has a fault; the semiconductor switch Q1 is kept in the on state, and if it is detected that the heater has no fault, a control signal is output through the second output terminal 8 of the heating control module to control the heating relay to turn on, and then the semiconductor switch Q1 is disconnected.

[0048] In this embodiment, the pulse width of the high-frequency square wave signal injected into the semiconductor switch Q1 can be fixed or adjustable. For example, if the pulse width of the high-frequency square wave signal is fixed, it is necessary to select a semiconductor switch with a suitable rated current, such as a semiconductor switch with a specification of 600A, which can quickly and directly determine whether the heating element (i.e., the heater) is faulty, and is more convenient to use. When the pulse width of the high-frequency square wave signal is adjustable, a semiconductor switch with a smaller rated current can be selected, such as a semiconductor switch with a rated current of 100A. At this time, it is only necessary to set the pulse width to always be within the safe working area of ​​the semiconductor switch Q1, so as to ensure that when there is overcurrent or short circuit, the junction temperature of the semiconductor switch will not be too high to cause burning within a short judgment time, and the heating element will not burn out, which can not only detect whether the heating element is faulty but also effectively save costs.

[0049] In the battery heating control circuit of this embodiment, since the semiconductor switch Q1 is connected in parallel at both ends of the relay K3 and is turned on before the relay K3 is closed, the current first flows through the branch where the semiconductor switch Q1 is located, and there is no pressure difference across the relay K3; only after the relay K3 is closed, the current will pass through the branch where the relay K3 is located, so that the heater works to generate heat, so no arc is generated when the relay K3 is closed, and on the basis of no arc generation, the switch contacts will not stick, thereby improving the reliability of the battery heating control circuit, and can effectively extend the service life of the relay, without the need for frequent replacement to increase maintenance costs.

[0050] In one embodiment, if Figure 1 and Figure 2 As shown, the battery heating control circuit also includes:

[0051] A current sampling module, the input end of the current sampling module is used to collect the branch current of the battery heating branch after the semiconductor switch Q1 is turned on; the output end of the current sampling module is connected to the input end 7 of the heating control module, and is used to send the branch current of the battery heating branch to the heating control module, and the heating control module is used to determine whether the heater has a fault based on the branch current.

[0052] The working process of the above battery heating control circuit is:

[0053] The heating control module sends a high-frequency square wave signal to the semiconductor switch Q1 to control the semiconductor switch Q1 to turn on. Then the heating control module obtains the branch current of the battery heating branch sent by the current sampling module, calculates the actual voltage of the heater based on the branch current, and detects whether the heater is faulty based on the actual voltage of the heater; the semiconductor switch Q1 is kept in the on state. If it is detected that the heater has no fault, the heating relay is controlled to turn on, and then the semiconductor switch Q1 is disconnected.

[0054] The battery heating control circuit of this embodiment, by setting a current sampling module at the input end of the heater, can determine whether the heating element is faulty according to the branch current of the battery heating branch. If the heater is faulty, the heater will not be allowed to work, thereby preventing the heater from working in an abnormal state and causing the circuit and device to burn, thereby improving the safety of the entire vehicle including the above-mentioned battery heating control circuit.

[0055] In one embodiment, the current sampling module is a current sensor or a shunt, and a sampling point of the current sampling module is arranged between the output end of the first resistor R2 and the input end of the heater.

[0056] If the current sampling module adopts a current sensor, the input end of the current sensor can be connected to the line between the output end of the first resistor R2 and the input end of the heater to detect the branch current of the battery heating branch.

[0057] In one embodiment, the second output end of the heating control module is connected to a relay coil branch, in which the coil of the heating relay is connected in series; the heating control module is used to control the coil of the heating relay to be turned on after determining that the heater is not faulty, so as to turn on the heating relay.

[0058] Among them, Figure 2 As shown, the second output terminal 8 of the heating control module (MCU) is connected to the relay coil branch (not shown in the figure), the coil of the heating relay is connected in series on the relay coil branch, and the normally open switch K3 of the heating relay is connected in series on the battery heating branch. When it is necessary to control the normally open switch K3 on the battery heating branch to be turned on, a high level signal is output through the second output terminal 8 of the heating control module to turn on the relay coil branch, so that the coil of the heating relay is energized, and then the normally open switch K3 of the heating relay is turned on.

[0059] In one embodiment, if Figure 1 As shown, the battery heating control circuit also includes:

[0060] A battery power supply branch, the battery power supply branch comprising: a total positive contactor K1, a total negative contactor K2, and a second resistor R1, wherein the input end of the total positive contactor K1 is connected to the positive electrode of the battery, the output end of the total negative contactor K2 is connected to the load, the input end of the total negative contactor K2 is connected to the load, and the output end of the total negative contactor K2 is connected to the negative electrode of the battery through the second resistor R1.

[0061] The working process of the above battery heating control circuit is:

[0062] First, the battery heating branch is controlled to be turned on. During the conduction period, it is detected whether there is a fault in the heater. When there is no fault and the temperature of the battery rises to the preset temperature, the battery heating branch is disconnected, and the total positive contactor K1 and the total negative contactor K2 are controlled to be turned on, so that the battery power supply branch is turned on and the battery supplies power to the load normally.

[0063] The battery heating control circuit of this embodiment can monitor in real time whether the heater is faulty before the battery power supply branch is turned on and during the process of the battery heating branch being turned on. If the heater is faulty, the heater will not be allowed to operate, thereby preventing the heater from operating in an abnormal state and causing the circuit and device to burn, thereby improving the safety of the entire vehicle.

[0064] In one embodiment, if Figure 2As shown, the third output terminal 10 of the heating control module is connected to the control end of the total positive contactor K1, and the fourth output terminal 9 of the heating control module is connected to the control end of the total negative contactor K2; the heating control module is used to control the total positive contactor K1 and the total negative contactor K2 to turn on the battery power supply branch after controlling the battery heating branch to be disconnected.

[0065] The working process of the above battery heating control circuit is:

[0066] First, the battery heating branch is controlled to be turned on, and whether there is a fault in the heater during the conduction period. When there is no fault and the temperature of the battery is increased to a preset temperature, the battery heating branch is disconnected; the third output terminal 10 and the fourth output terminal 9 of the heating control module output corresponding control signals to control the total positive contactor K1 and the total negative contactor K2 to be turned on, so that the battery power supply branch is turned on, and the battery supplies power to the load normally.

[0067] In one embodiment, if Figure 6 As shown, the battery heating control circuit also includes: a signal generating module, the output end of the signal generating module is connected to the input end of the heating relay, the output end of the heating relay is connected to the signal sampling module, the signal generating module is used to input a signal to the heating relay, the signal sampling module collects the signal and sends it to the heating control module, the heating control module generates a voltage signal waveform according to the signal, and compares it with a reference voltage signal waveform in a fault-free state to obtain a comparison result of the reference voltage signal, and determines whether the heater has a fault according to the comparison result.

[0068] In one embodiment, if Figure 3 As shown, a battery heating control method for a battery system is provided, wherein the battery heating control method is applied to the battery heating control circuit, and the battery heating control method comprises:

[0069] S301, sending a high-frequency square wave signal to the semiconductor switch Q1 to control the semiconductor switch Q1 to be turned on, and detecting whether the heater has a fault;

[0070] S302, if it is determined that the heater has no fault, the heating relay is controlled to be turned on, and the semiconductor switch Q1 is controlled to be turned off; if it is determined that the heater has a fault, the semiconductor switch Q1 is controlled to be turned off, and a fault alarm signal is generated;

[0071] S303, when it is detected that the temperature of the battery is within a normal temperature range, controlling the heating control module to be non-conductive.

[0072] In the above step S302, the heating control module can obtain the branch current of the battery heating branch sent by the current sampling module, calculate the actual voltage of the heater according to the branch current, compare the actual voltage with the reference voltage, and determine whether the heater is faulty according to the comparison result. When it is determined that the heater is faulty, the heating control module sends the generated fault alarm signal to the host.

[0073] The battery heating control method of this embodiment has the following advantages:

[0074] First, it can determine whether the heater is faulty. If the heater is faulty, the heater will not work, preventing the heater from working in an abnormal state and causing the circuit and device to burn, thereby improving the safety of the circuit.

[0075] Secondly, since the heater is fault-checked before it works, the protection of the circuit and the device is greatly improved, and there is no need to set an additional fuse, thus saving costs.

[0076] Third, semiconductor switches have a variety of specifications to choose from. Large-sized semiconductor switches can be selected for rapid detection, or small-sized semiconductor switches can be adjusted to meet demand and reduce costs by adjusting the signal pulse width.

[0077] Fourth, no arc is generated when the normally open switch K3 of the relay is closed, and the contacts of the normally open switch K3 will not stick together, which can extend the service life of the relay and reduce the cost of maintenance and replacement.

[0078] In one embodiment, in the above step S303, if Figure 4 As shown, detecting whether the heater is faulty specifically includes:

[0079] S401, controlling the current sampling module to collect the branch current output from the output end of the first resistor R2; calculating a voltage signal waveform of the heater according to the branch current, in combination with the terminal voltage of the battery and the resistance value of the first resistor R2;

[0080] S402, obtaining a reference voltage signal waveform diagram when the heater is in a non-fault state, comparing the voltage signal waveform diagram with the reference voltage signal waveform diagram to obtain a comparison result of the reference voltage signal, and determining whether the heater has a fault according to the comparison result.

[0081] Among them, the reference voltage signal waveform is a voltage signal waveform obtained when the heater is in normal working condition. Specifically, when the heater is in normal working condition, the standard branch current output from the output end of the first resistor R2 is calculated based on the standard branch current, the terminal voltage of the battery and the resistance value of the first resistor R2 to obtain the reference voltage signal waveform.

[0082] The battery heating control method of this embodiment determines whether the heater is faulty by comparing the signal waveform diagram, thereby ensuring that the relay is controlled when the heater is normal and without fault, achieving an arc-free closing effect of the relay and improving circuit safety.

[0083] In one embodiment, in the above S402, the voltage signal waveform diagram and the reference voltage signal waveform diagram are compared to obtain a comparison result of the reference voltage signal, and it is determined whether the heater has a fault according to the comparison result, such as Figure 5 As shown, including:

[0084] S501, extracting N first characteristic graphs of the voltage signal waveform graph and N second characteristic graphs of the reference voltage signal waveform graph, where N>2;

[0085] Among them, N first feature graphs of the voltage signal waveform graph and N second feature graphs of the reference voltage signal waveform graph can be extracted through a pre-trained waveform feature extraction model (such as an encoder), wherein the first feature graph and the second feature graph are both waveform features used to characterize the voltage signal waveform, the second feature graph is a standard waveform feature, and the first feature graph is a waveform feature to be compared.

[0086] S502, calculating the similarities between the N first feature graphs and the N second feature graphs to obtain N similarities; based on the comparison results of the N similarities with a preset similarity threshold, screening the number of similarities n greater than the similarity threshold, n≤N, as the comparison result of the reference voltage signal;

[0087] The similarity between the first feature sequence and the second feature sequence can be calculated by converting the first feature map and the second feature map into a first feature sequence and a second feature sequence, wherein the first feature sequence includes all pixel values ​​of the first feature map and the second feature sequence includes all pixel values ​​of the second feature map.

[0088] Through the above method, the similarities between N first feature sequences and the second feature sequences can be obtained, and the N similarities are compared with the set similarity threshold (for example, 0.8) to determine the number n of similarities greater than the similarity threshold, that is, n first feature maps among the N first feature maps match the corresponding second feature maps.

[0089] S503, when the similarity number n is greater than a preset similarity number threshold, confirming that the heater has no fault; when the similarity number n is not greater than the preset similarity number threshold, confirming that the heater has a fault.

[0090] Among them, whether the heater is faulty can be confirmed by setting an appropriate similarity number threshold. For example, the similarity number threshold can be set to 3N / 4, or 4N / 5, etc. When the similarity number n is greater than 3N / 4 or 4N / 5, it is determined that the heater is not faulty; when the similarity number n is not greater than 3N / 4 or 4N / 5, it is determined that the heater is faulty.

[0091] A first similarity quantity threshold and a second similarity threshold may also be set. For example, the first similarity quantity threshold may be set to 3N / 4, or 4N / 5, etc. When the similarity quantity n is greater than 3N / 4 or 4N / 5, it is determined that the heater is not faulty. The second similarity quantity threshold may be set to 2N / 4 or 3N / 5. When the similarity quantity n is not greater than 2N / 4 or 3N / 5, it is determined that the heater is faulty. When the similarity quantity n is between the first similarity quantity threshold and the second similarity threshold, it is necessary to collect the voltage signal waveform of the heater again for reprocessing and judgment.

[0092] The battery heating control method of this embodiment compares the signal waveform diagram by extracting the characteristic diagram in the waveform diagram and calculating the similarity of the characteristic diagram to determine whether the heater is faulty, thereby ensuring that the relay is controlled when the heater is normal and without fault, achieving an arc-free closing effect of the relay and improving circuit safety.

[0093] In one embodiment, controlling the heating control module to be non-conductive includes:

[0094] The semiconductor switch Q1 is first controlled to be turned on, and then the heating relay is controlled to be turned off; after the heating relay is turned off, the semiconductor switch Q1 is controlled to be turned off.

[0095] Among them, the semiconductor switch is controlled to be turned on first, and then the relay is controlled to be turned off, so that the relay can be turned off without arcing.

[0096] The embodiments described above are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such 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 invention, and should all be included in the protection scope of the present invention.

Claims

1. A battery heating control method for a battery system, characterized in that: The battery heating control method is applied to a battery heating control circuit, and the battery heating control circuit comprises: A battery heating branch, the battery heating branch comprising a heating relay, a first resistor R2 and a heater connected in series in sequence, and a semiconductor switch Q1 is connected in parallel at both ends of the heating relay; A heating control module, wherein the first output end of the heating control module is connected to the control end of the semiconductor switch, and the heating control module is used to send a high-frequency square wave signal to the semiconductor switch Q1 to control the semiconductor switch Q1 to be turned on, and detect whether the heater on the battery heating branch has a fault; if it is determined that the heater has no fault, the heating relay is controlled to be turned on, and the semiconductor switch Q1 is controlled to be turned off; The battery heating control method comprises: Sending a high-frequency square wave signal to the semiconductor switch Q1 to control the semiconductor switch Q1 to be turned on, and detecting whether the heater has a fault; If it is determined that the heater has no fault, the heating relay is controlled to be turned on and the semiconductor switch Q1 is controlled to be turned off; if it is determined that the heater has a fault, the semiconductor switch Q1 is controlled to be turned off and a fault alarm signal is generated; When it is detected that the temperature of the battery is within a normal temperature range, controlling the heating control module to be turned off; Detecting whether the heater is faulty includes: Collecting a branch current output from the output end of the first resistor R2; calculating a voltage signal waveform of the heater according to the branch current, in combination with the terminal voltage of the battery and the resistance value of the first resistor R2; A reference voltage signal waveform diagram of the heater in a non-fault state is obtained, the voltage signal waveform diagram is compared with the reference voltage signal waveform diagram to obtain a comparison result of the reference voltage signal, and whether the heater is faulty is determined according to the comparison result.

2. The battery heating control method according to claim 1, characterized in that: Comparing the voltage signal waveform with the reference voltage signal waveform to obtain a comparison result of the reference voltage signal, and determining whether the heater is faulty according to the comparison result, including: Extracting N first characteristic graphs of the voltage signal waveform graph and N second characteristic graphs of the reference voltage signal waveform graph, where N>2; Calculate the similarities between the N first feature graphs and the N second feature graphs to obtain N similarities; based on the comparison results of the N similarities with a preset similarity threshold, select the number of similarities n greater than the similarity threshold, n≤N, as the comparison result of the reference voltage signal; When the similarity number n is greater than a preset similarity number threshold, it is confirmed that the heater has no fault; when the similarity number n is not greater than the preset similarity number threshold, it is confirmed that the heater has a fault.

3. The battery heating control method according to claim 1, characterized in that: Controlling the heating control module to be non-conductive includes: The semiconductor switch Q1 is first controlled to be turned on, and then the heating relay is controlled to be turned off; after the heating relay is turned off, the semiconductor switch Q1 is controlled to be turned off.

4. The battery heating control method according to claim 1, characterized in that: The battery heating control circuit further includes: A current sampling module, wherein the input end of the current sampling module is used to collect the branch current of the battery heating branch after the semiconductor switch Q1 is turned on; the output end of the current sampling module is connected to the input end of the heating control module, and is used to send the branch current of the battery heating branch to the heating control module, and the heating control module is used to determine whether the heater is faulty based on the branch current.

5. The battery heating control method according to claim 4, characterized in that: The current sampling module is a current sensor or a shunt, and a sampling point of the current sampling module is arranged between the output end of the first resistor R2 and the input end of the heater.

6. The battery heating control method according to claim 4, characterized in that: The second output end of the heating control module is connected to a relay coil branch, in which the coil of the heating relay is connected in series; the heating control module is used to control the coil of the heating relay to be turned on after determining that the heater is not faulty, so as to turn on the heating relay.

7. The battery heating control method according to any one of claims 1 to 6, characterized in that: The battery heating control circuit further includes: A battery power supply branch, the battery power supply branch comprising: a total positive contactor K1, a total negative contactor K2, and a second resistor R1, wherein the input end of the total positive contactor K1 is connected to the positive electrode of the battery, the output end of the total negative contactor K2 is connected to the load, the input end of the total negative contactor K2 is connected to the load, and the output end of the total negative contactor K2 is connected to the negative electrode of the battery through the second resistor R1.

8. The battery heating control method according to claim 7, characterized in that: The third output end of the heating control module is connected to the control end of the total positive contactor K1, and the fourth output end of the heating control module is connected to the control end of the total negative contactor K2; The heating control module is used to control the battery heating branch to be turned on by controlling the main positive contactor K1 and the main negative contactor K2 after controlling the battery heating branch to be turned off.

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