Battery self-heating device and vehicle

Abstract

The present disclosure relates to a battery self-heating device and a vehicle, the device comprising: a battery self-heating circuit and a controller, the battery self-heating circuit comprising a first battery pack, a second battery pack, a bridge arm, and a winding corresponding to the bridge arm; a negative electrode of the first battery pack and a positive electrode of the second battery pack are connected, and the negative electrode of the first battery pack and the positive electrode of the second battery pack are connected with an output end of the winding, an input end of the winding is connected with a midpoint of the bridge arm; a positive electrode of the first battery pack is connected with a first bus end of the bridge arm, and a negative electrode of the second battery pack is connected with a second bus end of the bridge arm; the controller is configured to adjust a duty cycle of the bridge arm according to a target duty cycle range to make a fundamental frequency of a heating current of the battery self-heating circuit change in a target fundamental frequency range in response to detecting that the battery self-heating circuit is in a working state.

Description

Technical Field

[0001] This disclosure relates to the field of battery technology, and more specifically, to a battery self-heating device and a vehicle. Background Technology

[0002] With the development of technologies such as intelligent connectivity, electrification, and ADAS (Advanced Driving Assistance System), vehicle electronic control devices can all be sources of EMC (Electromagnetic Compatibility) interference, and the electromagnetic environment faced by new energy vehicles is even more complex.

[0003] In related technologies, new energy vehicles can utilize battery self-heating; however, the fundamental frequency generated during this process produces significant electromagnetic interference. Therefore, reducing the electromagnetic interference generated during battery self-heating is a pressing technical problem that needs to be solved. Summary of the Invention

[0004] This summary section is provided to briefly introduce the concepts, which will be described in detail in the detailed description section below. This summary section is not intended to identify key or essential features of the claimed technical solution, nor is it intended to limit the scope of the claimed technical solution.

[0005] In a first aspect, this disclosure provides a battery self-heating device, comprising: a battery self-heating circuit and a controller, wherein the battery self-heating circuit includes a first battery pack, a second battery pack, a bridge arm, and a winding corresponding to the bridge arm;

[0006] The negative terminal of the first battery pack is connected to the positive terminal of the second battery pack, and the negative terminal of the first battery pack and the positive terminal of the second battery pack are connected to the output terminal of the winding, and the input terminal of the winding is connected to the midpoint of the bridge arm;

[0007] The positive terminal of the first battery pack is connected to the first busbar of the bridge arm, and the negative terminal of the second battery pack is connected to the second busbar of the bridge arm;

[0008] The controller is configured to adjust the duty cycle of the bridge arm according to a target duty cycle range in response to detecting that the battery self-heating circuit is in operation, so that the fundamental frequency of the heating current of the battery self-heating circuit varies within the target fundamental frequency range, wherein the target duty cycle range is obtained based on the mapping relationship between the fundamental frequency and the duty cycle.

[0009] Optionally, the controller is configured to:

[0010] Within a preset time period, a target duty cycle is randomly selected from the target duty cycle range, and the duty cycle of the bridge arm is adjusted according to the target duty cycle so that the fundamental frequency of the heating current varies within the target fundamental frequency range.

[0011] Optionally, the controller is configured to:

[0012] Within a preset time period, according to the target duty cycle range, the duty cycle of the bridge arm is sequentially adjusted to a first lower limit, a first upper limit, and a first lower limit, so that the fundamental frequency of the heating current changes sequentially to a second lower limit, a second upper limit, and a second lower limit.

[0013] The first lower limit and the first upper limit are obtained based on the target duty cycle range, and the second lower limit and the second upper limit are obtained based on the target fundamental frequency range.

[0014] Optionally, the controller is configured to:

[0015] Obtain the time-domain waveform of the heating current, which is used to reflect the change of the heating current in the time domain;

[0016] The time-domain waveform is subjected to Fourier transform to obtain the frequency-domain waveform, which is used to reflect the change of the heating current in the frequency domain.

[0017] The duty cycle of the bridge arm is adjusted according to the noise amplitude in the frequency domain waveform, so as to adjust the fundamental frequency of the heating current accordingly.

[0018] Optionally, the bridge arm is a multi-phase bridge arm, the winding is a multi-phase winding, the multi-phase bridge arm and the multi-phase winding correspond one-to-one, and each phase winding is connected to the midpoint of the corresponding bridge arm.

[0019] Optionally, the battery self-heating circuit further includes a first capacitor and a second capacitor;

[0020] The first terminal of the second capacitor is connected to the second terminal of the first capacitor, the first terminal of the second capacitor and the second terminal of the first capacitor are connected to the output terminal of the winding, the second terminal of the second capacitor is connected to the negative terminal of the second battery pack, and the first terminal of the first capacitor is connected to the positive terminal of the first battery pack.

[0021] Optionally, the battery self-heating circuit further includes a first switch, and the first end of the second capacitor and the second end of the first capacitor are connected to the output end of the winding through the first switch.

[0022] Optionally, the battery self-heating circuit further includes a second switch, through which the negative terminal of the first battery pack and the positive terminal of the second battery pack are connected to the output terminal of the winding.

[0023] Optionally, the winding is a winding in a motor on a vehicle, and the bridge arm is a bridge arm switch in the vehicle used to control the motor.

[0024] Optionally, the battery self-heating circuit further includes a DC charging port, the output terminal of the winding is connected to the positive terminal of the DC charging port, and the second bus terminal of the bridge arm is connected to the negative terminal of the DC charging port.

[0025] Optionally, the battery self-heating circuit further includes a third switch, wherein the first bus terminal of the bridge arm is connected to the first terminal of the third switch, and the second terminal of the third switch is connected to the positive terminal of the DC charging port.

[0026] In a second aspect, this disclosure provides a vehicle that includes the battery self-heating device described in any one of the first aspects above.

[0027] By adjusting the duty cycle of the bridge arm according to the target duty cycle range, the fundamental frequency of the heating current in the battery self-heating circuit varies within the target fundamental frequency range. This results in a continuously changing sinusoidal heating current within the target fundamental frequency range. Since the current waveform is sinusoidal, the amplitude of the heating current waveform is the same, thereby distributing the electromagnetic interference intensity to other frequency points and reducing the magnetic induction intensity caused by EMC. Simultaneously, it effectively reduces the amplitude of electromagnetic interference within the target fundamental frequency range.

[0028] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0029] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and the originals and elements are not necessarily drawn to scale. In the drawings:

[0030] Figure 1 This is a structural block diagram of a battery self-heating device according to an exemplary embodiment of the present disclosure.

[0031] Figure 2 This is a circuit diagram of a battery self-heating circuit according to an exemplary embodiment of the present disclosure.

[0032] Figure 3 This is a schematic diagram of the current flow direction of timing 1 according to an exemplary embodiment of the present disclosure.

[0033] Figure 4 This is a schematic diagram of the current flow direction of timing 2 according to an exemplary embodiment of the present disclosure.

[0034] Figure 5 This is a schematic diagram of the current flow direction of timing 3 according to an exemplary embodiment of the present disclosure.

[0035] Figure 6 This is a schematic diagram of the current flow direction of timing 4 according to an exemplary embodiment of the present disclosure.

[0036] Figure 7 This is a waveform diagram of heating current at a fixed fundamental frequency, as shown in an exemplary embodiment of the present disclosure.

[0037] Figure 8 This is a schematic diagram illustrating the variation of the low-frequency magnetic field amplitude of a battery self-heating circuit at a fixed fundamental frequency, according to an exemplary embodiment of this disclosure.

[0038] Figure 9 This is a schematic diagram of the waveform of the heating current at the fundamental frequency, as shown in an exemplary embodiment of the present disclosure.

[0039] Figure 10 This is a schematic diagram illustrating the change in the low-frequency magnetic field amplitude of a battery self-heating circuit at a varying fundamental frequency, according to an exemplary embodiment of this disclosure.

[0040] Explanation of reference numerals in the attached figures

[0041] S1 - Battery self-heating circuit, 1 - Bridge arm, 11 - Upper bridge arm, 12 - Lower bridge arm, 2 - Winding, E1 - First battery pack, E2 - Second battery pack, C1 - First capacitor, C2 - Second capacitor, K1 - First switch, K2 - Second switch, K3 - Third switch, K4 - Fourth switch, K5 - Fifth switch. Detailed Implementation

[0042] Embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings. While some embodiments of this disclosure are shown in the drawings, it should be understood that this disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this disclosure. It should be understood that the accompanying drawings and embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of protection of this disclosure.

[0043] The term "comprising" and its variations as used herein are open-ended inclusions, meaning "including but not limited to". The term "based on" means "at least partially based on". The term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments". Definitions of other terms will be given in the description below.

[0044] It should be noted that the concepts of "first" and "second" mentioned in this disclosure are used only to distinguish different devices, modules or units, and are not used to limit the order of functions performed by these devices, modules or units or their interdependencies.

[0045] It should be noted that the terms "a" and "a plurality of" used in this disclosure are illustrative rather than restrictive, and those skilled in the art should understand that, unless otherwise expressly indicated in the context, they should be understood as "one or more".

[0046] The names of messages or information exchanged between multiple devices in the embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of such messages or information.

[0047] As mentioned in the background section, the electromagnetic environment faced by new energy vehicles is more complex because their power comes directly from the electric drive system. For example, the high voltage and high current transients during the switching of high-power semiconductor switching devices in the electric drive system emit strong radiation and electromagnetic interference. Furthermore, in the self-heating scheme of the electric drive system, the fixed fundamental frequency used for battery self-heating generates a large amplitude of electromagnetic interference.

[0048] However, new energy vehicles have high EMC requirements for sensitive electronic components. Furthermore, high electromagnetic interference (EMI) amplitudes can negatively impact human health in the long run. Related technologies can employ the following methods to reduce EMI amplitude: using high-quality encapsulation materials to cover interference sources within the vehicle; materials with strong anti-interference capabilities can effectively reduce the intensity of EMI signals during propagation, thus lowering the EMI amplitude; and using filters, employing resistors and inductors in RC circuits to filter and reduce EMI signals, thereby lowering their amplitude. However, both using encapsulation materials and filters increase costs and cannot effectively reduce EMI amplitudes within the fundamental frequency band.

[0049] In view of this, this disclosure proposes a battery self-heating device that can effectively reduce the amplitude of electromagnetic interference caused by the fundamental frequency during the battery self-heating process. The battery heating device of this disclosure will be described in detail below.

[0050] Figure 1This is a structural block diagram of a battery self-heating device according to an exemplary embodiment of the present disclosure. Figure 1 As shown, the device includes a battery self-heating circuit S1 and a controller (not shown in the diagram). Figure 1 As shown in the diagram, the battery self-heating circuit S1 includes a first battery pack E1, a second battery pack E2, a bridge arm 1, and a winding 2 corresponding to the bridge arm 1; the negative terminal of the first battery pack E1 and the positive terminal of the second battery pack E2 are connected, and the negative terminal of the first battery pack E1 and the positive terminal of the second battery pack E2 are connected to the output terminal of the winding 2, and the input terminal of the winding 2 is connected to the midpoint of the bridge arm 1; the positive terminal of the first battery pack E1 is connected to the first bus terminal of the bridge arm 1, and the negative terminal of the second battery pack E2 is connected to the second bus terminal of the bridge arm 1; the controller is configured to adjust the duty cycle of the bridge arm 1 according to a target duty cycle range in response to detecting that the battery self-heating circuit S1 is in an operating state, so that the fundamental frequency of the heating current of the battery self-heating circuit S1 varies within the target fundamental frequency range, the target duty cycle range being obtained based on the mapping relationship between the fundamental frequency and the duty cycle.

[0051] In some embodiments, the controller can also be configured to control the battery self-heating circuit S1 to enter the working state. For example, the controller can also be configured to control the alternating on and off of the upper and lower bridge arms included in the bridge arm 1, so that the first battery pack E1 and the second battery pack E2 are charged or discharged through the winding 2 respectively, triggering the battery self-heating circuit S1 to enter the working state. It can be seen that the battery self-heating circuit S1 achieves self-heating through the alternating oscillation of the battery.

[0052] In some embodiments, the bridge arm can be a multi-phase bridge arm, and the winding can be a multi-phase winding. There is a one-to-one correspondence between the multi-phase bridge arm and the multi-phase winding, and each phase winding is connected to the midpoint of its corresponding bridge arm; that is, the input terminal of each phase line of the winding is connected to the midpoint of its corresponding bridge arm. For a multi-phase winding, the output terminal of the winding can be the midpoint of the phase line output terminal of the multi-phase winding. For example... Figure 1 As shown, a multiphase bridge arm can be a three-phase bridge arm, and a multiphase winding can be a three-phase winding.

[0053] It is worth noting that the battery self-heating circuit of this disclosure can be any self-heating circuit that charges or discharges the first and second battery packs through the oscillating current generated by the bridge arm and winding to achieve battery self-heating. This disclosure does not impose any limitation on the number of phases of the bridge arm and winding; for example, the bridge arm can also be a single-phase bridge arm, and the winding can be a single-phase winding corresponding to the single-phase bridge arm.

[0054] To more clearly illustrate the self-heating principle of the battery self-heating circuit disclosed herein, the following will use... Figure 1 The self-heating circuit of the battery shown will be explained.

[0055] For example, the battery self-heating circuit can go through the following 4 timing sequences:

[0056] Timing 1: The upper bridge arm 11 of bridge arm 1 is closed, and the lower bridge arm 12 is opened. Current flows from the positive terminal of the first battery pack E1, through the upper bridge arm 11 to charge winding 2, and then the charging current returns to the negative terminal of the first battery pack E1 through the output terminal of the winding. During this stage, the first battery pack E1 discharges to charge winding 2. For details on the current flow direction corresponding to timing 1, please refer to [link to relevant documentation]. Figure 3 .

[0057] Timing 2: Disconnect the upper bridge arm 11 of bridge arm 1 and close the lower bridge arm 12. Current flows from the output terminal of winding 2 to charge the second battery pack E2, and then returns to the input terminal of winding 2 via the lower bridge arm 12. During this stage, winding 2 discharges to charge the second battery E2. For details on the current flow direction corresponding to timing 2, please refer to [link to relevant documentation]. Figure 4 .

[0058] By switching back and forth between timing 1 and timing 2, the first battery pack E1 can be discharged and the second battery pack E2 can be charged.

[0059] Timing 3: Disconnect the upper bridge arm 11 of bridge arm 1 and close the lower bridge arm 12. Current flows from the positive terminal of the second battery pack E2 to charge winding 2, and then returns to the negative terminal of the second battery pack E2 via the lower bridge arm 12. During this stage, the second battery pack E2 discharges to charge winding 2. For details on the current flow direction corresponding to timing 3, please refer to [link to relevant documentation]. Figure 5 .

[0060] Timing 4: Close the upper bridge arm 11 of bridge arm 1 and open the lower bridge arm 12. Current flows from the input terminal of winding 2, through the upper bridge arm 11 of bridge arm 1 to charge the first battery pack E1, and returns to the output terminal of winding 2. During this stage, winding 2 discharges to charge the first battery pack E1. For information on the current flow direction corresponding to timing 4, please refer to [link to relevant documentation]. Figure 6 .

[0061] By switching back and forth between timing sequence 3 and timing sequence 4, the charging of the first battery pack E1 and the discharging of the second battery pack E2 can be achieved.

[0062] Therefore, by switching back and forth between timing sequences 1 and 2, and timing sequences 3 and 4, the charging and discharging of the first battery pack E1 and the second battery pack E2 can be completed. In some embodiments, the first battery pack E1 and the second battery pack E2 can together constitute a high-voltage power battery. By alternating the charging and discharging currents of the first battery pack E1 and the second battery pack E2, the battery ripple during the battery oscillation heating process can be further reduced.

[0063] like Figure 2As shown, in some embodiments, the battery self-heating circuit may further include a first capacitor C1 and a second capacitor C2; the first terminal of the second capacitor C2 is connected to the second terminal of the first capacitor C1, the first terminal of the second capacitor C2 and the second terminal of the first capacitor C1 are connected to the output terminal of the winding 2, the second terminal of the second capacitor C2 is connected to the negative terminal of the second battery pack E2, and the first terminal of the first capacitor C1 is connected to the positive terminal of the first battery pack E1. In some embodiments, the first capacitor C1 and the second capacitor C2 may be X capacitors, which are capacitors used to suppress electromagnetic interference from the power supply.

[0064] By connecting two capacitors in parallel across the first battery pack E1 and the second battery pack E2, namely the first capacitor C1 and the second capacitor C2, the carrier frequency of the self-heating circuit can be suppressed. By suppressing the carrier frequency, EMC interference can be further reduced.

[0065] like Figure 2 As shown, in some embodiments, the battery self-heating circuit may further include a first switch K1, and the first terminal of the second capacitor C2 and the second terminal of the first capacitor C1 are connected to the output terminal of the winding 2 through the first switch K1. By setting the first switch K1, the carrier frequency suppression function of the battery self-heating circuit can be easily activated or deactivated. Activating the carrier frequency suppression function can further improve the effect of the battery self-heating circuit in reducing electromagnetic interference. In some embodiments, the controller may also be configured to control the first switch K1 to conduct in response to detecting that the battery self-heating circuit is in an operating state, thereby activating the carrier frequency suppression function of the battery self-heating circuit.

[0066] like Figure 2 As shown, in some embodiments, the battery self-heating circuit may further include a second switch K2, with the negative terminal of the first battery pack E1 and the positive terminal of the second battery pack E2 connected to the output terminal of the winding 2 via the second switch K2. By setting the second switch K2, the self-heating function of the battery self-heating circuit can be easily started or stopped, thus facilitating control of the battery self-heating circuit to be in working condition. In some embodiments, the controller may also be configured to control the second switch K2 to be turned on to start the self-heating function of the battery self-heating circuit, triggering the battery self-heating circuit to enter working condition.

[0067] In some embodiments, winding 2 is a winding in a motor on a vehicle, and bridge arm 1 is a bridge arm switch in a vehicle used to control the motor.

[0068] like Figure 2 As shown, in some embodiments, the battery self-heating circuit further includes a DC charging port, with the output terminal of winding 2 connected to the positive terminal of the DC charging port, and the second bus terminal of bridge arm 1 connected to the negative terminal of the DC charging port. Direct charging of the vehicle can be achieved by providing the DC charging port.

[0069] like Figure 2 As shown, in some embodiments, the battery self-heating circuit may further include a third switch K3. The first bus terminal of bridge arm 1 is connected to the first terminal of the third switch K3, and the second terminal of the third switch K3 is connected to the positive terminal of the DC charging port. By setting the third switch K3, it is easier to control the vehicle's direct charging. In some embodiments, the controller may also be configured to control the first switch K1 to open, the second switch K2 to open, and the third switch K3 to open, so that the vehicle can perform direct charging. The controller can control the first switch K1 to open, the second switch K2 to open, and the third switch K3 to open when it detects that the vehicle needs to perform direct charging.

[0070] like Figure 2 As shown, in some embodiments, the battery self-heating circuit may further include a fourth switch K4 and a fifth switch K5. The output terminal of the winding 2 is connected to the positive terminal of the DC charging port through the fourth switch K4, and the second bus terminal of the bridge arm 1 is connected to the negative terminal of the DC charging port through the fifth switch K5. The controller may be configured to control the first switch K1 to be off, the second switch K2 to be off, the third switch K3 to be on, the fourth switch K4 to be off, and the fifth switch K5 to be on, so that the vehicle can be directly charged.

[0071] In some embodiments, the controller can also be configured to control the first switch K1 to open, the second switch K2 to open, the third switch K3 to open, the fourth switch K4 to open, and the fifth switch K5 to open, so that the vehicle can perform boost charging. The controller can control the first switch K1 to open, the second switch K2 to open, the third switch K3 to open, the fourth switch K4 to open, and the fifth switch K5 to open when it detects that the vehicle needs to perform boost charging.

[0072] In some embodiments, the controller may also be configured to control the first switch K1 to open, the second switch K2 to open, the third switch K3 to open, the fourth switch K4 to open, and the fifth switch K5 to open, so that the vehicle can drive normally.

[0073] As previously stated, the controller is configured to adjust the duty cycle of the bridge arm according to a target duty cycle range in response to detecting that the battery self-heating circuit is in operation. This is to ensure that the fundamental frequency of the heating current of the battery self-heating circuit varies within the target fundamental frequency range, which is obtained based on the mapping relationship between the fundamental frequency and the duty cycle. For example, taking the aforementioned timing sequences 1-4 as an example, assuming that the total duration of timing sequences 1 and 2 is t1, and the total duration of timing sequences 3 and 4 is t2, then the duty cycle of the bridge arm could be t1 / (t1+t2).

[0074] Since the battery self-heating circuit heats the battery through oscillation, the oscillating current waveform during the self-heating process is a PWM (Pulse Width Modulation) waveform. The PWM waveform acts as a carrier wave, and its frequency is the carrier frequency. By applying sinusoidal pulse width modulation to the PWM wave, a sinusoidal pulse sequence can be obtained; this waveform is the fundamental wave, and its frequency is the fundamental frequency. Modulating the carrier frequency modulates the pulse width, thereby changing the fundamental frequency.

[0075] For frequencies (e.g., carrier frequency or fundamental frequency), frequency relates to period, and frequency is the reciprocal of period. Pulse width and duty cycle relate to period. Pulse width is the time the high-level signal occupies within one period, and duty cycle is the proportion of the high-level signal within one period. For example, assuming the frequency is F and the duty cycle is P, then pulse width = (1 / F)*P. Therefore, the duty cycle is directly proportional to the fundamental frequency.

[0076] The target duty cycle range can be the duty cycle range required to achieve the target fundamental frequency range. The target duty cycle range can be preset according to the mapping relationship between the fundamental frequency and the duty cycle.

[0077] This disclosure adjusts the duty cycle of the bridge arm according to a target duty cycle range, causing the fundamental frequency of the heating current in the battery's self-heating circuit to vary within the target fundamental frequency range. This results in a continuously varying sinusoidal heating current within the target fundamental frequency range. Compared to the fixed fundamental frequency schemes in related technologies, the current waveform of this disclosure is sinusoidal, so the amplitude of the heating current waveform is the same. This effectively distributes the electromagnetic interference intensity to other frequency points, reducing the magnetic induction intensity caused by EMC. Simultaneously, it also effectively reduces the amplitude of electromagnetic interference within the target fundamental frequency range.

[0078] In some embodiments, the controller can vary the fundamental frequency of the heating current within a target fundamental frequency range in various ways. In some embodiments, the controller can be configured to randomly select a target duty cycle from a target duty cycle range within a preset time period, and adjust the duty cycle of the bridge arm according to the target duty cycle, so that the fundamental frequency of the heating current varies within the target fundamental frequency range. Randomly selecting the target duty cycle allows for random variation of the fundamental frequency of the heating current.

[0079] In some embodiments, the controller is configured to: within a preset duration, sequentially adjust the duty cycle of the bridge arm to a first lower limit, a first upper limit, and a first lower limit value according to a target duty cycle range, so that the fundamental frequency of the heating current sequentially changes to a second lower limit, a second upper limit, and a second lower limit value; wherein the first lower limit and the first upper limit value are obtained according to the target duty cycle range, and the second lower limit and the second upper limit value are obtained according to the target fundamental frequency range. By sequentially changing the fundamental frequency to the second lower limit, the second upper limit, and the second lower limit value, fundamental frequency conversion (i.e., changing the fundamental frequency) can be achieved within one cycle; correspondingly, the preset duration can be the cycle of this fundamental frequency conversion.

[0080] In some embodiments, the preset duration can be specifically determined according to the actual situation. For example, the preset duration can be arbitrarily selected from (0, 1) seconds. The preset duration can be selected as short as possible to improve the EMC suppression effect.

[0081] In some embodiments, the target fundamental frequency range can be specifically determined according to actual conditions. For example, if the target fundamental frequency range is 40Hz-60Hz, then the second lower limit can be 40Hz, and the second upper limit can be 60Hz. Correspondingly, the first upper limit can be the duty cycle corresponding to the fundamental frequency of 60Hz, and the first lower limit can be the duty cycle corresponding to the fundamental frequency of 40Hz. For example, this disclosure can change the fundamental frequency from 40Hz to 60Hz and then back to 40Hz by adjusting the duty cycle, thereby achieving fundamental frequency conversion within one cycle. Correspondingly, this cycle can be a preset duration.

[0082] For example, see reference Figure 7 , Figure 7 This is a waveform diagram of the heating current at a fixed fundamental frequency, where... Figure 7 Waveform 7a is the time-domain waveform of the heating current, where the X-axis represents time and the Y-axis represents the current magnitude. Waveform 7b is the frequency-domain waveform of the self-heating current, i.e., the frequency-domain discrete signal corresponding to the Fourier transform of the time-domain waveform. According to... Figure 7 The noise amplitude at a frequency of 50Hz is 51.5dB. Figure 8 This is a schematic diagram showing the change in the low-frequency magnetic field amplitude of a battery self-heating circuit at a fixed fundamental frequency. The X-axis of this waveform represents the frequency, and the Y-axis represents the low-frequency magnetic field amplitude. Figure 4 It can be seen that at a frequency of 50Hz, the amplitude of the low-frequency magnetic field is 1251.1ut.

[0083] refer to Figure 9 , Figure 9 This is a waveform diagram of the heating current under varying fundamental frequency, where... Figure 9Waveform 9a is the time-domain waveform of the self-heating current, with the X-axis representing time and the Y-axis representing the current magnitude. Waveform 9b is the frequency-domain waveform of the self-heating current, i.e., the frequency-domain discrete signal corresponding to the Fourier transform of the time-domain waveform. According to... Figure 9 The noise amplitude at 50Hz is 21dB. Compared to Figure 7 Changing the fundamental frequency weakens the 50Hz peak, resulting in a smoother waveform and reduced noise amplitude. (Reference) Figure 10 , Figure 10 This is a schematic diagram showing the change in the low-frequency magnetic field amplitude of a battery self-heating circuit under varying fundamental frequencies. The X-axis of this waveform represents the frequency, and the Y-axis represents the low-frequency magnetic field amplitude. Figure 10 At a frequency of 50Hz, the amplitude of the low-frequency magnetic field is 1120ut. Compared to... Figure 8 The change in fundamental frequency weakened the amplitude of the low-frequency magnetic field at 50 Hz.

[0084] Depend on Figure 7-10 It can be seen that by changing the fundamental frequency of the heating current in the battery self-heating circuit, the noise amplitude and low-frequency magnetic field amplitude can be significantly reduced, thus reducing the intensity of electromagnetic interference.

[0085] In some embodiments, the controller can be configured to: acquire the time-domain waveform of the heating current, which reflects the change of the heating current in the time domain; perform a Fourier transform on the time-domain waveform to obtain a frequency-domain waveform, which reflects the change of the heating current in the frequency domain; and adjust the duty cycle of the bridge arm according to the noise amplitude in the frequency-domain waveform to adjust the fundamental frequency of the heating current accordingly. The forms of the time-domain and frequency-domain waveforms can be referred to the above. Figure 7 or Figure 9 This will not be elaborated upon here.

[0086] For example, after obtaining the frequency domain waveform, the controller can increase the duty cycle to raise the fundamental frequency in response to the noise amplitude exceeding a preset threshold, thereby reducing the noise amplitude. By adjusting the fundamental frequency of the heating current based on the noise amplitude of the frequency domain waveform, the controller can more accurately adjust the fundamental frequency, thus better suppressing EMC interference.

[0087] This disclosure also proposes a vehicle that includes any of the aforementioned battery self-heating devices. Specific details regarding the vehicle in this embodiment have been described in detail in the embodiments concerning the relevant battery self-heating devices, and will not be elaborated upon here.

[0088] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0089] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0090] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A battery self-heating device, characterized in that, include: A battery self-heating circuit and controller, wherein the battery self-heating circuit includes a first battery pack, a second battery pack, a bridge arm, and a winding corresponding to the bridge arm; The negative terminal of the first battery pack is connected to the positive terminal of the second battery pack, and the negative terminal of the first battery pack and the positive terminal of the second battery pack are connected to the output terminal of the winding, and the input terminal of the winding is connected to the midpoint of the bridge arm; The positive terminal of the first battery pack is connected to the first busbar of the bridge arm, and the negative terminal of the second battery pack is connected to the second busbar of the bridge arm; The controller is configured to, in response to detecting that the battery self-heating circuit is in operation, randomly select a target duty cycle from a target duty cycle range within a preset time period, and adjust the duty cycle of the bridge arm according to the target duty cycle, so that the fundamental frequency of the heating current of the battery self-heating circuit varies within the target fundamental frequency range. The target duty cycle range is obtained based on the mapping relationship between the fundamental frequency and the duty cycle. The target duty cycle range is the duty cycle range required to achieve the target fundamental frequency range. The preset time period is greater than 0 seconds and less than or equal to 1 second. The controller is further configured to: acquire the time-domain waveform of the heating current, the time-domain waveform being used to reflect the change of the heating current in the time domain; perform a Fourier transform on the time-domain waveform to obtain a frequency-domain waveform, the frequency-domain waveform being used to reflect the change of the heating current in the frequency domain; and adjust the duty cycle of the bridge arm according to the noise amplitude in the frequency-domain waveform to correspondingly adjust the fundamental frequency of the heating current.

2. The battery self-heating device according to claim 1, characterized in that, The controller is configured to: Within a preset time period, according to the target duty cycle range, the duty cycle of the bridge arm is sequentially adjusted to a first lower limit, a first upper limit, and a first lower limit, so that the fundamental frequency of the heating current changes sequentially to a second lower limit, a second upper limit, and a second lower limit. The first lower limit and the first upper limit are obtained based on the target duty cycle range, and the second lower limit and the second upper limit are obtained based on the target fundamental frequency range.

3. The battery self-heating device according to claim 1, characterized in that, The bridge arm is a multi-phase bridge arm, the winding is a multi-phase winding, the multi-phase bridge arm and the multi-phase winding are in one-to-one correspondence, and each phase winding is connected to the midpoint of the corresponding bridge arm.

4. The battery self-heating device according to claim 1 or 3, characterized in that, The battery self-heating circuit also includes a first capacitor and a second capacitor. The first terminal of the second capacitor is connected to the second terminal of the first capacitor, the first terminal of the second capacitor and the second terminal of the first capacitor are connected to the output terminal of the winding, the second terminal of the second capacitor is connected to the negative terminal of the second battery pack, and the first terminal of the first capacitor is connected to the positive terminal of the first battery pack.

5. The battery self-heating device according to claim 4, characterized in that, The battery self-heating circuit also includes a first switch, and the first end of the second capacitor and the second end of the first capacitor are connected to the output end of the winding through the first switch.

6. The battery self-heating device according to claim 1 or 5, characterized in that, The battery self-heating circuit also includes a second switch, through which the negative terminal of the first battery pack and the positive terminal of the second battery pack are connected to the output terminal of the winding.

7. The battery self-heating device according to claim 1 or 3, characterized in that, The winding is the winding in the motor of the vehicle, and the bridge arm is the bridge arm switch in the vehicle used to control the motor.

8. The battery self-heating device according to claim 1, characterized in that, The battery self-heating circuit also includes a DC charging port, the output end of the winding is connected to the positive terminal of the DC charging port, and the second bus terminal of the bridge arm is connected to the negative terminal of the DC charging port.

9. The battery self-heating device according to claim 8, characterized in that, The battery self-heating circuit also includes a third switch, the first bus terminal of the bridge arm is connected to the first terminal of the third switch, and the second terminal of the third switch is connected to the positive terminal of the DC charging port.

10. A vehicle, characterized in that, Includes the battery self-heating device described in any one of claims 1-9 above.

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