AC battery heating

Abstract

This invention provides a method and system for heating a battery pack using alternating current (AC). [Solution] A system for managing the battery pack of an electric vehicle 100 includes a sensor and a controller. The sensor detects the temperature associated with the battery pack. The controller sends a request to a charger based on the sensor signal from the sensor and supplies at least a portion of the alternating current received from the charger in relation to the request to at least the first battery cells of the battery pack to generate heat based on the internal resistance of the first battery cells, thereby raising the temperature associated with the first battery cells.

Description

[Technical Field]

[0001] [Cross-reference of related applications] This application claims priority to U.S. Patent Application No. 19 / 244520, “ALTERNATING CURRENT BATTERY HEATING,” filed on 20 June 2025, and further claims priority to U.S. Provisional Patent Application No. 63 / 717,719, “ALTERNATING CURRENT BATTERY HEATING,” filed on 7 November 2024. The entirety of each of these disclosures is incorporated herein by reference for all purposes.

[0002] This disclosure relates to battery heating. More specifically, embodiments of this disclosure relate to methods and systems for heating a battery pack using alternating current (AC). [Background technology]

[0003] Electric vehicles may experience performance degradation in cold climate conditions. For example, battery packs used in electric vehicles may face challenges when charged at low temperatures (e.g., below 0°C). Under certain low-temperature conditions, vehicles may be unable to charge their battery packs, resulting in long waiting times at charging stations and potentially causing some vehicles to lose power completely. Furthermore, charging at low temperatures can lead to battery cell degradation and lithium deposition, potentially impacting the lifespan and performance of the energy storage system. [Overview of the Initiative]

[0004] Each of the systems, methods, and devices disclosed herein has several innovative embodiments, and not just one of them alone is responsible for all of the desirable attributes disclosed herein. Details of one or more implementations of the subject matter described herein are given in the accompanying drawings and the following description.

[0005] In some embodiments, the technology described herein relates to a system for managing a battery pack of an electric vehicle, the system comprising: a sensor configured to detect a temperature associated with the battery pack; and a controller communicating with the sensor, configured to transmit a request to a charger based on a sensor signal from the sensor, the request identifying an AC waveform; and to supply at least a portion of the AC associated with the request and received from the charger to at least a first battery cell of the battery pack such that heat is generated based on the internal resistance of the first battery cell to raise the temperature associated with the first battery cell.

[0006] In some embodiments, the technology described herein relates to a system in which the controller is configured to send a request to the charger in response to determining, based on sensor signals, that the temperature associated with the battery pack meets a threshold.

[0007] In some embodiments, the technology described herein relates to a system, where the requirement specifies at least one of the amplitude, frequency, or direct current (DC) offset of an alternating current.

[0008] In some embodiments, the technology described herein relates to a system in which the controller is configured to determine at least one of amplitude, frequency, or DC offset based on at least one of the cell type of the battery pack, the temperature associated with the battery pack, or the charge state of the battery pack.

[0009] In some embodiments, the technology described herein relates to a system in which the frequency of the alternating current is in the range of 80 hertz (Hz) to 500 Hz.

[0010] In some embodiments, the technology described herein relates to a system in which the amplitude of the alternating current is in the range of 100 amperes to 1000 amperes.

[0011] In some embodiments, the technology described herein relates to a system in which the controller is configured to monitor AC and send updated requests based on the monitoring of AC.

[0012] In some embodiments, the technology described herein relates to an electric vehicle, the electric vehicle comprising a plurality of battery cells, including a first battery cell, and a battery management system configured to detect a state relating to the plurality of battery cells, and in response to the detection of a state, to send a request to a charger, and to supply at least a portion of the alternating current relating to the request and received from the charger to at least the first battery cell such that the internal resistance and alternating current of the first battery cell raise the temperature relating to the first battery cell.

[0013] In some embodiments, the technology described herein relates to an electric vehicle, and the state includes at least one of the following: temperature associated with a plurality of battery cells, charge state of a plurality of battery cells, or cell type of a plurality of battery cells.

[0014] In some embodiments, the technology described herein relates to an electric vehicle, where the requirement specifies an alternating current to a direct current (DC) offset, and the battery management system determines the DC offset based at least partially on the temperature associated with a plurality of battery cells.

[0015] In some embodiments, the technology described herein relates to an electric vehicle, and the battery management system is configured to supply alternating current to a plurality of battery cells in order to charge at least one of the plurality of battery cells.

[0016] In some embodiments, the technology described herein further relates to an electric vehicle comprising one or more other components, wherein the battery management system provides alternating current for supplying power to one or more other components, and one or more other components include at least one of a drive unit, a compressor, or a power conversion system.

[0017] In some aspects, the technology described herein relates to an electric vehicle, and the requirement is to specify the AC amplitude and DC offset, and the battery management system is configured to determine the amplitude and DC offset based at least in part on the state.

[0018] In some aspects, the technology described herein relates to an electric vehicle, and the battery management system is configured to monitor the AC amplitude to generate a monitoring signal, generate an updated requirement for adjusting the AC amplitude based on the monitoring signal, and transmit the updated requirement to a charger.

[0019] In some aspects, the technology described herein relates to a method for managing a battery pack. The method includes detecting a temperature associated with the battery pack, transmitting a requirement to identify an AC waveform to a charger based on the temperature, and supplying the AC received in relation to the requirement and received from the charger to at least a first battery cell of the battery pack such that heat is generated based on the internal resistance of the first battery cell to raise the temperature associated with the first battery cell.

[0020] In some aspects, the technology described herein relates to a method, which further includes monitoring an AC amplitude to generate a monitoring signal, and transmitting an updated requirement for adjusting the AC amplitude to a charger based on the monitoring signal.

[0021] In some aspects, the technology described herein relates to a method, which further includes determining that the temperature associated with the battery pack meets a threshold value, and the requirement is transmitted in response to determining that the temperature associated with the battery pack meets the threshold value.

[0022] In some embodiments, the technology described herein relates to a method, the method further comprising the step of determining amplitude, frequency, and DC offset based on at least one of the cell type of a battery pack, a temperature associated with the battery pack, and the charge state of the battery pack, wherein the AC waveform exhibits amplitude, frequency, and DC offset.

[0023] In some embodiments, the technology described herein relates to a method, the method further comprising the step of supplying alternating current to power a drive unit, compressor, or power conversion system of an electric vehicle.

[0024] In some embodiments, the techniques described herein relate to methods, where the frequency of the alternating current is 80 Hz to 500 Hz.

[0025] In some embodiments, the technology described herein relates to a charger for charging and heating a battery pack of an electric vehicle, the charger comprising: a plurality of voltage converters configured to generate alternating current based on control signals and transmit the alternating current to an electric vehicle; and a controller communicating with the plurality of voltage converters, which is configured to receive a request from the electric vehicle for heating the battery pack, and in response to the request, generate a control signal and transmit it to the plurality of voltage converters, causing the plurality of voltage converters to transmit alternating current to the electric vehicle relating to the request in order to heat the battery pack. [Brief explanation of the drawing]

[0026] Embodiments of the present disclosure will be described with reference to the accompanying drawings, in which similar reference numerals refer to similar elements.

[0027] [Figure 1A] This is an exemplary schematic diagram of components of an exemplary vehicle that can carry out the embodiments of the present disclosure.

[0028] [Figure 1B] Figure 1A is an exemplary schematic diagram of an exemplary vehicle according to some embodiments of the present disclosure.

[0029] [Figure 2] This is a schematic diagram of the components of an exemplary charger that can be used to carry out the embodiments of the present disclosure.

[0030] [Figure 3] This graph shows heating performance related to various heating methods.

[0031] [Figure 4] This is a schematic diagram of the components of a charger for charging an electric vehicle according to several embodiments.

[0032] [Figure 5] This graph compares the phase of the current at the charger post in Figure 4 with the phase of the high voltage on the charger bus in Figure 4.

[0033] [Figure 6] Figure 4 is a schematic diagram of the components of a charger for controlling alternating current (AC) ripple across multiple DC-DC voltage converters, according to several embodiments. [Modes for carrying out the invention]

[0034] The following descriptions of specific embodiments present various descriptions of those specific embodiments. However, the innovations described herein can be implemented in numerous different ways, for example, as defined and encompassed by the claims. In this description, similar reference numbers refer to drawings in which the terms may represent identical or functionally similar elements. It will be understood that the elements shown in the drawings are not necessarily drawn to scale. Furthermore, it will be understood that a particular embodiment may include more elements and / or subsets of elements shown in the drawings than those shown. In addition, some embodiments may incorporate any suitable combination of features from two or more drawings. Any suitable principles and advantages of the embodiments disclosed herein can be implemented together with one another.

[0035] Generally speaking, one or more aspects of the present disclosure relate to methods and systems for heating an electric vehicle battery pack using alternating current (AC). Such heating can improve charging performance in cold climate conditions. As used herein, AC can include current in the form of sinusoidal, pulsed, rippled, square wave, sawtooth wave, etc. Some embodiments of the present disclosure relate to a charging system (e.g., a system that can include components in the charger and components in the vehicle) that generates heat for heating the battery pack by utilizing the internal resistance of the battery cells in the battery pack, by supplying AC from a charger (e.g., a charging station) through a charging port in the vehicle to one or more battery cells in the battery pack. The AC provided can be a signal (e.g., an electrical signal) that can be described using various types of signal waveforms (e.g., sinusoidal, square wave, sawtooth, pulsed, ripple, etc.). The AC may have a DC offset (e.g., a deviation of the baseline of the AC signal). For example, an AC with a DC offset may oscillate near a non-zero baseline rather than near zero.

[0036] In some embodiments, upon detecting a trigger condition (e.g., the battery pack temperature is below a threshold), the electric vehicle (e.g., the electric vehicle's battery management system (BMS)) may send a request to the charger to heat the battery pack. In response to receiving the request, the charger may generate and provide alternating current (e.g., a synchronous AC signal provided to one or more battery cells) to heat the battery cells of the battery pack (e.g., using the AC and internal resistance of the battery cells of the battery pack) before, during, and / or after charging the battery pack. The vehicle may also provide information specifying the waveform of the AC for which the charger generates the AC for heating.

[0037] Advantageously, by utilizing alternating current to generate heat using the internal resistance of the battery cells, the charging system can heat the battery cells more effectively compared to certain other methods, achieving higher energy efficiency as well as faster heating. For example, the disclosed AC heating method can achieve an efficiency of over 90%, compared to less than 50% for certain coolant-based heating methods. The improved efficiency of AC heating may be due to reduced losses when conducting AC to the battery cells and direct heat generation within the battery cells, which can reduce thermal barriers and heat loss. Advantageously, the charging system can quickly bring the battery pack to a better or optimal charging temperature, even in extremely cold conditions. This rapid heating capability can enable charging a vehicle within a relatively short time (e.g., within 15 minutes at an ambient temperature of -20°C).

[0038] The charging system can utilize existing hardware in both the electric vehicle and the charger, enabling relatively low-cost and / or retrofitting in existing vehicle fleets. For example, on the charger side, the charging system can synchronize DC-DC converters (e.g., bidirectional or isolated DC-DC converters) to constructively generate the AC required by the electric vehicle (e.g., AC with amplitude, frequency, and / or DC offset specified by the electric vehicle). On the electric vehicle side, the charging system can utilize existing hardware related to the charging port and BMS, and control the existing hardware (e.g., via updated firmware) to achieve battery heating. By enabling rapid heating of the battery pack, the charging system can significantly improve the overall vehicle charging speed and charging station throughput. This reduces customer waiting times and increases the overall efficiency of the charging infrastructure.

[0039] Generally, an electric vehicle charging system or charging system can refer to the infrastructure and technology used to charge electric vehicles (EVs). A charging system typically includes charging stations, connectors, and associated software, firmware, and hardware for managing the charging process. Charging systems can vary in terms of power levels, from relatively slow chargers using standard household outlets to relatively fast chargers or charging stations that can recharge EV batteries in significantly shorter times. Charging systems play a role in providing efficient, safe, and reliable energy transfer to the vehicle's battery pack, ensuring that EVs are ready for use.

[0040] A key technical challenge in electric vehicle charging is efficiently charging battery packs under cold climate conditions. Lithium-ion batteries, widely used in EVs, may have limited ability to receive charge at temperatures below 0°C. Charging at such low temperatures can also lead to battery degradation and lithium deposition, potentially impacting battery performance and lifespan. Furthermore, low temperatures may prevent vehicles from charging altogether, leading to long wait times at charging stations and potentially causing some vehicles to lose power completely.

[0041] Certain technical solutions for charging battery packs under cold climate conditions include heating the battery pack using heat generated outside of it. For example, some systems use a heated coolant to warm the battery pack. This method may involve circulating a heated fluid through the battery pack to raise its temperature. However, this technique may be less than 50% efficient due to thermal barriers and heat loss. Furthermore, the performance of heat pumps, which can be used in conjunction with coolant-based heating, may be significantly reduced at low temperatures due to the lack of ambient heat to supply.

[0042] To address at least some of the above problems, some embodiments of the present disclosure relate to a charging system that utilizes the internal resistance of battery cells within a battery pack to heat the battery pack by supplying alternating current from a charger to the battery cells within the battery pack through a charging port. In some embodiments, when the BMS of an electric vehicle decides to heat the battery pack, the BMS sends a request to heat the battery pack to a charger, such as a charging station. For example, the BMS may decide to heat the battery pack in response to the detection that the temperature of the battery pack has fallen below a threshold and / or in response to the detection of one or more other conditions (e.g., frost or ice accumulating on the battery pack, weather conditions such as a blizzard, etc.).

[0043] The request can specify one or more parameters related to the AC generated by and injected from the charger (e.g., amplitude, frequency, DC offset, model number related to the battery cell). In some embodiments, the BMS can determine the amplitude, frequency, and DC offset related to the AC based on one or more of the following: battery cell type, temperature related to the battery pack, charge state of the battery pack, etc.

[0044] For example, if the temperature associated with the battery pack is very low (e.g., below -20°C), the BMS may request a higher amplitude AC compared to a situation where the temperature associated with the battery pack is higher (e.g., around -5°C) to accelerate the heating process. As another example, if the temperature associated with the battery pack is above 0°C, the BMS may decide that the battery pack can be charged using DC. In this example, instead of generating AC without a DC offset, the BMS may request that the AC be generated with a DC offset of a specific offset value, which may depend on how quickly the battery pack needs to be charged using DC. As yet another example, the BMS may request that the AC be generated with a DC offset to power one or more other components of the electric vehicle (e.g., drive unit, compressor, power conversion system, etc.), regardless of the battery pack temperature. Advantageously, by using AC to power the other components, power from the battery pack may not be used.

[0045] In some embodiments, the BMS may request an AC having a frequency in the range of 80Hz to 320Hz, 100Hz to 200Hz, 100Hz to 500Hz, or any other suitable range of 80Hz to 500Hz. In some embodiments, the BMS may request an AC having an amplitude in the range of 100A to 600A, 200A to 600A, 200A to 900A, 300A to 800A, 100A to 700A, 600A to 1000A, and / or any other suitable range of 100A to 1000A. In some examples, the frequency of the AC signal requested by the BMS may be the same as the AC applied to the battery cell (e.g., without intermediate conversion) or different (e.g., by intermediate conversion of the received AC to a higher or lower frequency).

[0046] In response to receiving a request, the charger can generate alternating current (AC) on the request. The AC is supplied to the electric vehicle's charging port and then flows into the battery pack to heat the battery pack before and / or during charging (e.g., using the heat generated by the internal resistance of the battery cells in the battery pack). In some embodiments, the charger can utilize DC-DC converters to generate and synchronize the AC, supply it to the electric vehicle, and / or inject it into the battery pack. For example, the charger may include multiple (e.g., four) DC-DC converter sets, each DC-DC converter set may include one or more (e.g., four) DC-DC converters capable of generating an AC waveform. Each DC-DC converter set can convert a signal on a high-voltage DC bus (e.g., about 900 volts) into a desired AC waveform. The DC-DC converter set can be configured to generate an AC waveform according to specific amplitude, frequency, and DC offset required by the electric vehicle's BMS. In some embodiments, each DC-DC converter in the DC-DC converter set can generate a portion of the AC supplied to the battery pack. The individual AC waveforms generated by the DC-DC converters in a DC-DC converter set may be phase-matched and frequency-matched, thereby enabling the individual AC waveforms to be constructively added together to generate the required AC. In some embodiments, the amplitude of the AC may be distributed among the DC-DC converters in the DC-DC converter set. In some embodiments, if a vehicle requires an AC with an amplitude of 400 amperes (A) and the DC-DC converter set has four DC-DC converters, each DC-DC converter in the DC-DC converter set can generate an AC waveform with an amplitude of 100 A.

[0047] In some embodiments, the charger can monitor signals on a high-voltage DC bus and / or signals output by a DC-DC converter set to maintain synchronization between AC waveforms generated by the DC-DC converters in the DC-DC converter set and / or protect the charger's components from damage. More specifically, the charger can operate without digital synchronization technology to synchronize the outputs (e.g., current) of the DC-DC converters in the DC-DC converter set. Instead, the charger can maintain synchronization by monitoring the voltage on the high-voltage DC bus and / or the AC waveforms generated by each DC-DC converter set (e.g., based on the monitored phase and / or frequency of the voltage on the high-voltage DC bus). Advantageously, this monitoring also allows the charger to detect abnormal or excessive currents flowing through capacitors connected to the high-voltage DC bus and supplying current to the DC-DC converter set. Thus, the capacitors are not damaged or subjected to excessive load.

[0048] Additionally and / or optionally, to avoid stressing or damaging the capacitors supplying current to the DC-DC converter sets, the input signals (e.g., input voltage or input current) to at least some of the DC-DC converter sets can be controlled to be out of phase with each other. For example, instead of supplying four common-phase input signals to each of four DC-DC converter sets, two of the four DC-DC converter sets can receive input signals of a first phase, and the other two sets of the four DC-DC converter sets can receive input signals of a second phase opposite to the first phase. As another example, the input signals to a DC-DC converter set can be out of phase with other input signals to other DC-DC converter sets. Optionally, by avoiding supplying all common-phase signals to the DC-DC converter sets, the charger can reduce stress on the capacitors. This can prevent or stop the capacitors from being subjected to excessive load.

[0049] During periods when the battery pack is heating, the BMS of an electric vehicle can monitor the heating process and adjust parameters (e.g., amplitude, frequency, DC offset, etc.) based on the monitored results. The BMS can adjust one or more parameters dynamically and / or periodically. In some embodiments, the BMS can monitor the AC amplitude, frequency, and / or DC offset received from the charger and compare the monitored amplitude, frequency, and / or DC offset with those requested by the BMS. For example, if the BMS determines that the AC amplitude is smaller than the requested amplitude, the BMS can send an updated request to the charger. The updated request may request a higher amplitude compared to the previously requested one. Conversely, if the BMS determines that the AC amplitude is higher than the requested one or higher than an appropriate level, the BMS can send an updated request to the charger to reduce the AC amplitude.

[0050] As described above, the BMS can request alternating current with a DC offset. In some embodiments, during the heating process, the BMS can also distribute alternating current with a DC offset between the battery pack and one or more other components of the electric vehicle. For example, if the temperature of the battery pack is above a threshold (e.g., above 0°C), the BMS can allow alternating current with a DC offset to be supplied to the battery pack. Thus, the AC component of the AC can be used to heat the battery pack, and the DC component of the AC can be used to charge the battery. On the other hand, if the BMS determines that the temperature of the battery pack is below the threshold, the BMS may separate the AC component and the DC component of the AC (e.g., using filtering techniques). For example, the BMS can allow supplying only the AC component to the battery pack to heat it, and use the DC component of the AC to charge or power one or more other components of the electric vehicle (e.g., drive unit, compressor, power conversion system, etc.).

[0051] In some embodiments, the BMS may use one or more control algorithms to manage the distribution of AC and DC components. For example, based on the battery pack temperature, charge state, and / or other factors, the BMS may determine the amount of AC component to be used for heating and the amount of DC component to be used for charging. Advantageously, the control algorithm can ensure that the battery pack is heated efficiently without impairing the charging process. Additionally and / or optionally, the BMS may dynamically and / or periodically adjust the separation of AC and DC components based on real-time conditions. For example, if the battery pack temperature rises above a certain threshold, the BMS may reduce the AC component used for heating and increase the DC component used for charging. This dynamic and / or periodic adjustment can achieve optimal vehicle performance and safety. In addition to coordinating the heating and charging of the battery pack as described above, the BMS may distribute the AC and DC components of the alternating current from the charger to other auxiliary loads within the electric vehicle. For example, the DC component can be used to power heating, ventilation, and air conditioning (HVAC) systems, drive units, and / or other high-voltage devices, while the AC and DC components can be used to charge and heat battery packs. This distribution can enable all vehicle systems to operate efficiently and effectively.

[0052] Many of the aforementioned aspects of this disclosure and the associated advantages will be more readily understood by referring to the following description in conjunction with the accompanying drawings.

[0053] Figure 1A is an exemplary schematic block diagram of components of an exemplary electric vehicle 100 that can carry out embodiments of the present disclosure. The electric vehicle 100 includes a battery pack 104, a BMS 102, a charging port 106, a power conversion system 108, a compressor 110, a drive unit 112, and an internal LV 114, as shown in Figure 1A. The electric vehicle 100 also includes a coolant loop that can heat and cool the battery pack 104. Although the BMS 102 is shown as being part of the battery pack 104, it should be noted that in some other embodiments, the BMS 102 may be separate from the battery pack 104 or external.

[0054] The battery pack 104 may include a plurality of lithium-ion battery cells for storing electrical energy for the vehicle. As described above, the internal resistance of the battery cells can be utilized to generate heat when alternating current is applied, thereby heating the battery cells from the inside. For example, the electrical resistance of a jelly roll can generate heat within the battery cell. The BMS 102 may be or include an electrical control unit (ECU) associated with the battery pack. The BMS 102 may include any suitable circuitry for performing the functions of the BMS disclosed herein. Advantageously, by utilizing the alternating current and the internal resistance of the battery cells, heat can be generated uniformly and / or efficiently within the battery cells. The internal resistance can result in heating without damaging the battery cells each time current passes through them. Furthermore, heating can be performed more rapidly compared to other methods (e.g., using a heat pump or cooling, resistance heating, or other heating mechanisms from outside the battery cells).

[0055] The power conversion system 108 can convert electrical energy from a charger (e.g., charger 200 in Figure 2) into a form that can be used by the battery pack 104 and / or other high-voltage (HV) devices within the electric vehicle 100. The compressor 110 may be part of the vehicle's HVAC system. The HVAC system can be used to manage the temperature inside the electric vehicle 100. The drive unit 112 may include an electric motor and associated components that provide propulsion for the electric vehicle 100. The internal low-voltage (LV) system 114 may refer to a low-voltage electrical system within the electric vehicle 100 that powers various auxiliary devices and systems. The power conversion system 108 can generate power for the internal LV system 114.

[0056] The charging port 106 can serve as an interface for the electric vehicle 100 to connect to the charger 200. The charging port 106 facilitates the transfer of electrical energy from the charger 200 to the battery pack 104 and other components. The charging port 106 can also function as a communication link between the electric vehicle 100 and the charger 200, facilitating the transmission of requests from the BMS 102 for AC to heat the battery pack 104. In such cases, the electronic control unit (ECU) 116 of the charging port 106 can facilitate such requests. The ECU 116 of the charging port 106 can communicate requests to the post-controller of the charger post 202 in Figure 2, and the post-controller can communicate requests to the bus controller 210 in Figure 2. The bus controller 210 in Figure 2 can control the DC-DC converter set 212A, 212B, 212C, and / or 212D in Figure 2 to generate AC current for battery heating. In some applications, requests from the BMS102 can be transmitted wirelessly to the charger 200 shown in Figure 2.

[0057] In some embodiments, once the BMS 102 decides to heat the battery pack 104, the BMS 102 may send a request to the charger 200 to heat the battery pack 104. The request may be sent to the charger 200 via the charging port 106 in a particular application. For example, the BMS 102 may decide to heat the battery pack 104 in response to the detection that the temperature of the battery pack 104 has fallen below a threshold and / or the detection of one or more other conditions (e.g., frost or ice, snow, etc., accumulating on the battery pack).

[0058] The request can specify one or more parameters (e.g., amplitude, frequency, DC offset, etc.) related to the AC generated by and injected from the charger 200. In some embodiments, the BMS 102 can determine one or more of the amplitude, frequency, and DC offset related to the AC based on one or more of the following: the battery cell type of the battery pack 104, the temperature associated with the battery pack 104, the charge state of the battery pack 104, etc.

[0059] For example, if the temperature associated with the battery pack 104 is very low (e.g., below -20°C), the BMS 102 may request a higher amplitude AC compared to a situation where the temperature associated with the battery pack 104 is higher (e.g., around -5°C) to accelerate the heating process. As another example, if the temperature associated with the battery pack 104 is above 0°C, the BMS 102 may decide that the battery pack 104 can be charged using DC. In this example, instead of generating AC without a DC offset, the BMS 102 may request that the AC be generated with a DC offset of a specific offset value that may depend on how quickly the battery pack 104 needs to be charged using DC. As yet another example, the BMS 102 may request that the AC be generated with a DC offset to power other components of the electric vehicle 100 (e.g., the drive unit 112, compressor 110, power conversion system 108, etc.), regardless of the temperature of the battery pack 104.

[0060] In some embodiments, the BMS102 may request an AC with a frequency in the range of 80Hz to 320Hz, 100Hz to 200Hz, 100Hz to 500Hz, or any other suitable range of 80Hz to 500Hz. In some embodiments, the BMS102 may request an AC with an amplitude in the range of 600A to 1000A, 200A to 900A, 300A to 800A, 100A to 700A, and / or any other suitable range of 100A to 1000A.

[0061] Any suitable hardware in the vehicle can send a request to the charger to generate an AC current for heating the battery. For example, the request can be transmitted wirelessly via the charging port 106 and / or via the antenna. In some cases, the vehicle 100 can transmit information that allows the charger 200 in Figure 2 to determine and generate an AC waveform for heating the battery.

[0062] Next, the battery pack 104 can be charged using the AC power received from the charger 200 in Figure 2. While the battery pack 104 is heating, the BMS 102 may monitor the heating process and adjust parameters (e.g., amplitude, frequency, DC offset, etc.) based on the monitoring results. Parameters can be adjusted dynamically. Parameters can be adjusted periodically. In some embodiments, the BMS 102 may monitor one or more of the amplitude, frequency, or DC offset of the AC power received from the charger 200 and compare the monitored amplitude, frequency, and / or DC offset with those requested by the BMS 102. For example, if the BMS 102 determines that the AC amplitude is smaller than the requested amplitude, the BMS 102 can send an updated request to the charger 200. The updated request may request a higher amplitude compared to the previously requested one. On the other hand, if the BMS 102 determines that the AC amplitude is higher than the requested one or higher than an appropriate level, the BMS 102 can send an updated request to the charger 200 to reduce the AC amplitude.

[0063] In some embodiments, the BMS 102 may require alternating current with a DC offset. In some embodiments, during the heating process, the BMS 102 may also distribute alternating current with a DC offset between the battery pack 104 and one or more other components of the electric vehicle. For example, if the temperature of the battery pack 104 exceeds a threshold (e.g., above 0°C), the BMS 102 may allow alternating current with a DC offset to be injected into the battery pack 104. Thus, the AC component of the alternating current can be used to heat the battery pack 104, and the DC component of the alternating current can be used to charge the battery pack 104. On the other hand, if the BMS 102 determines that the temperature of the battery pack 104 is above a threshold, the BMS 102 may separate the AC component of the alternating current from the DC component of the alternating current (e.g., using filtering techniques). For example, the BMS 102 can inject only the AC component into the battery pack 104 to heat it, and can use the DC component of the AC to power one or more other components of the electric vehicle 100 (e.g., the drive unit 112, the compressor 110, the power conversion system 108, etc.).

[0064] In some embodiments, the BMS 102 can use one or more control algorithms to manage the distribution of AC and DC components. For example, based on the battery pack temperature, charge state, and / or other factors, the BMS 102 can determine the amount of AC component used for heating and the amount of DC component used for charging. Advantageously, the control algorithm can ensure that the battery pack 104 is heated efficiently without impairing the charging process. Additionally and / or optionally, the BMS 102 can dynamically adjust the separation of AC and DC components based on real-time conditions. For example, if the battery pack temperature rises above a certain threshold, the BMS 102 can reduce the AC component used for heating and increase the DC component used for charging. This dynamic adjustment can achieve optimal vehicle performance and safety. In addition to coordinating the heating and charging of the battery pack 104 as described above, the BMS 102 can distribute the AC and DC components of the alternating current from the charger 200 to one or more other auxiliary loads in the electric vehicle. For example, some DC component can be used to power the heating, ventilation, and air conditioning (HVAC) system, compressor 110, drive unit 112, or one or more other high-voltage devices, while the AC component and some DC component can be used to charge and heat the battery pack 104. This distribution can enable all vehicle systems to operate efficiently and effectively.

[0065] Figure 1B is an exemplary schematic diagram of an exemplary electric vehicle 100 of Figure 1A, according to some embodiments of the present disclosure. The electric vehicle 100 may include a battery pack 104, a controller 140, sensors 150, and components 160, as shown in Figure 1B. In some examples, the controller 140 may include or implement the BMS 102 of Figure 1A. For example, the controller 140 may include any suitable hardware (e.g., a processor and memory) to perform the functions described with reference to the BMS 102 of Figure 1A. The components 160 may include a power conversion system 108, a compressor 110, a drive unit 112, or other components related to the electric vehicle 100.

[0066] In some embodiments, the sensor 150 is configured to detect the temperature associated with the battery pack 104. The sensor 150 can be a thermistor, thermocouple, resistance thermometer, infrared sensor, semiconductor temperature sensor, etc. The controller 140 can communicate with the sensor 150. The controller 140 can send a request to a charger (e.g., charger 200 as described with reference to Figure 2) based on the sensor signal from the sensor 150. The request can identify the AC waveform of the AC generated by the charger. The controller 140 can supply the AC associated with the request received from the charger to at least the first battery cell of the battery pack 104 so as to generate heat based on the internal resistance of the first battery cell and raise the temperature associated with the first battery cell.

[0067] Figure 2 is a diagram of the components of a charger 200 that can carry out embodiments of the present disclosure. As shown in Figure 2, the charger 200 includes at least a charger post 202A, a charger cabinet 204, and a field manager controller 206. The charger cabinet 204 includes an AC-DC power stage 208, a bus controller 210, and DC-DC converter sets 212A, 212B, 212C, and 212D. As described above, the charger 200 can generate alternating current for heating the battery pack 104 of the electric vehicle 100. The charger 200 can generate alternating current for charging / powering one or more other components of the electric vehicle 100. The charger 200 can be, for example, a Tesla Supercharger. In some embodiments, the charger 200 and at least some parts of the electric vehicle 100 can form a charging system for charging and / or heating the battery pack.

[0068] The charger 200 may include multiple charger cabinets 204. For example, the charger 200 may include seven charger cabinets 204-204N as shown in the figure. Each charger cabinet 204 can supply power to multiple charger posts 202 (e.g., 202A, 202B, 202C, 202D, and / or 202N). Each of the charger posts 202 can charge its own electric vehicle. Each of the charger posts 202 can receive power from each of the DC-DC converter sets 212A-212D in the charger cabinet 204. As shown in the example in Figure 2, there are four DC-DC converter sets 212A, 212B, 212C, and 212D, and each of the four DC-DC converter sets 212A, 212B, 212C, and 212D includes four DC-DC converters. In some embodiments, the charger 200 can charge up to four vehicles via charger posts 202A, 202B, 202C, and 202D, which correspond to DC-DC converter sets 212A, 212B, 212C, and 212D, respectively. For example, the charger 200 can charge an electric vehicle 100 via DC-DC converter set 212A and charger post 202A.

[0069] The charger post 202 can function as a physical interface between the electric vehicle 100 and the charger 200 in Figure 1A. The charger post 202 can house connectors and cables that facilitate the transfer of electrical energy from the charger 200 to the electric vehicle 100. The charger post 202 may also include one or more communication interfaces that allow the electric vehicle 100 (e.g., BMS 102) to send a request to heat the battery pack and receive a response from the charger 200.

[0070] The charger cabinet 204 may include power conversion and control components for the charger 200. The charger cabinet 204 houses an AC-DC power stage 208, a bus controller 210, and DC-DC converter sets 212A, 212B, 212C, and 212D. These components can work together to convert grid power into a desired AC waveform and synchronize the output for heating the electric vehicle 100 using AC heating.

[0071] The field manager controller 206 can oversee the operation of the charger cabinet 204. The field manager controller 206 can adjust the power distribution and ensure that the charger cabinet 204 operates within its capacity. The field manager controller 206 can also manage communication between the charger 200 and other components of the charging station. These other components may include connections to the battery energy storage system 220, the backend 225, and the grid 230.

[0072] The AC-DC power stage 208 of the charger cabinet 204 can convert grid power from the grid 230 into a voltage signal on the high-voltage direct current (DC) bus 250. The AC-DC power stage 208 can output a 900-volt signal to the high-voltage DC bus 250, and the signal can serve as input to the DC-DC converter sets 212A, 212B, 212C, and 212D. The AC-DC power stage 208 can ensure that the voltage signal on the high-voltage DC bus 250 is stable and can supply power to heat the battery pack 104. The AC-DC power stage 208 can contain five AC-DC power stages.

[0073] The bus controller 210 can manage the high-voltage DC bus 250 and coordinate the operation of the DC-DC converter sets 212A, 212B, 212C, and 212D. The bus controller 210 can receive requests from the BMS 102 in Figure 1A and translate these requests into commands for the DC-DC converter sets 212A, 212B, 212C, and 212D. The bus controller 210 can manage and control the DC-DC converter sets 212A, 212B, 212C, and 212D to generate the desired AC with the requested amplitude, frequency, and / or DC offset.

[0074] The DC-DC converter sets 212A, 212B, 212C, and 212D may include any suitable DC-DC converters capable of converting signals on the high-voltage DC bus 250 into AC for heating the battery pack 104. Each of the DC-DC converter sets 212A, 212B, 212C, and 212D may include one or more DC-DC converters. As described above and shown in Figure 2, each of the illustrated DC-DC converter sets 212A, 212B, 212C, and 212D includes four DC-DC converters. However, one or more of the DC-DC converter sets 212A, 212B, 212C, and 212D may include any other suitable number of DC-DC converters. Each DC-DC converter set may generate a portion of the AC, and the outputs of the DC-DC converters in the DC-DC converter set may be synchronized to constructively add up to the required amplitude, frequency, and / or DC offset. Furthermore, the DC-DC converter sets 212A, 212B, 212C, and 212D can generate AC with varying amplitude, frequency, and DC offset, as specified by BMS102 in Figure 1A.

[0075] In response to receiving a request from the electric vehicle 100 in Figure 1A to heat the battery pack 104, the charger 200 can generate alternating current on the request and inject it into the battery pack 104 in Figure 1A to heat the battery pack 104 before and / or during charging (for example, by utilizing the heat generated by the internal resistance of the battery cells in the battery pack 104). As described above, the bus controller 210 can control the AC-DC power stage 208 and the DC-DC converter sets 212A, 212B, 212C, and 212D to generate and synchronize alternating current to supply to the battery pack 104. For example, each of the DC-DC converter sets 212A, 212B, 212C, and 212D can convert a signal on the high-voltage DC bus 250 into a desired AC waveform. The DC-DC converter sets 212A, 212B, 212C, and 212D can be configured to generate AC waveforms according to specified amplitude, frequency, and DC offset required by the BMS 102. In some embodiments, each of the DC-DC converters in the DC-DC converter sets 212A, 212B, 212C, and 212D can generate a portion of the AC that is injected into the battery pack 104. The individual AC waveforms generated by each of the DC-DC converters in the DC-DC converter sets 212A, 212B, 212C, and 212D may be phase-matched and frequency-matched so that the individual AC waveforms can be constructively rather than destructively added together to generate the required AC. The amplitude of the AC may be distributed among the DC-DC converters in the DC-DC converter sets 212A, 212B, 212C, and 212D. For example, if BMS102 requests an AC waveform with an amplitude of 400A from DC-DC converter set 212A, each DC-DC converter in DC-DC converter set 212A can generate an AC waveform with an amplitude of 100A.

[0076] In some embodiments, the charger 200 (e.g., bus controller 210) can monitor signals on the high-voltage DC bus 250 and / or signals output by the DC-DC converter sets 212A, 212B, 212C, and 212D to maintain synchronization between the AC waveforms generated by the DC-DC converters of the DC-DC converter sets 212A, 212B, 212C, and 212D, and / or protect components of the charger 200 from damage. More specifically, the bus controller 210 can operate without digital synchronization technology to synchronize the outputs (e.g., current) associated with the DC-DC converter sets 212A, 212B, 212C, and 212D. Alternatively, each of the DC-DC converter sets 212A, 212B, 212C, and 212D, and / or each DC-DC converter in each set, can monitor the voltage on the high-voltage DC bus 250 to maintain synchronization (for example, based on the monitored phase and / or frequency of the voltage on the high-voltage DC bus 250). For example, DC-DC converter set 212B can monitor the voltage on the high-voltage DC bus 250 to synchronize the DC-DC converters within DC-DC converter set 212B. Each of the DC-DC converter sets 212A, 212B, 212C, and 212D can also monitor the voltage ripple amplitude on the high-voltage DC bus 250 to ensure that there is no excess current flowing into and / or out of the capacitors (not shown in Figure 2) connected to the high-voltage DC bus 250 and supplying current to the DC-DC converter sets 212A, 212B, 212C, and 212D. Furthermore, the bus controller 210 can also add up the current consumed by each of the DC-DC converter sets 212A, 212B, 212C, and 212D to ensure that the total current consumed by the DC-DC converter sets 212A, 212B, 212C, and 212D is below the maximum limit. Thus, the capacitors will not be damaged or subjected to excessive load.

[0077] Additionally and / or optionally, to reduce stress on the capacitors supplying current to DC-DC converter sets 212A, 212B, 212C, and 212D, the input signals (e.g., input voltage or input current) to at least some of the DC-DC converter sets 212A, 212B, 212C, and 212D can be controlled to be out of phase with each other. For example, instead of supplying each of the DC-DC converter sets 212A, 212B, 212C, and 212D with four in-phase input signals, DC-DC converter sets 212A and 212B can receive input signals of a first phase, and DC-DC converter sets 212C and 212D can receive input signals of a second phase opposite to the first phase. As another example, each of the DC-DC converter sets 212A, 212B, 212C, and 212D can receive input signals that are out of phase with the input signals received by the other DC-DC converter sets. By selectively avoiding supplying all common-mode signals to the DC-DC converter sets 212A, 212B, 212C, and 212D, the bus controller 210 can prevent the capacitors from being subjected to excessive load.

[0078] In some embodiments, the charger 200 can be used to charge and heat the battery pack of an electric vehicle (e.g., the battery pack 104 of the electric vehicle 100). The charger 200 may include a plurality of voltage converters (e.g., DC-DC converter sets 212A, 212B, 212C, and 212D) and a controller (e.g., a bus controller 210) that communicates with the plurality of voltage converters. The plurality of voltage converters may be configured to generate alternating current based on control signals and transmit the alternating current to the electric vehicle. The controller may be configured to receive requests regarding the heating of the battery pack. In response to a request, the controller may generate and transmit control signals to the plurality of voltage converters. The controller can then cause the plurality of voltage converters to transmit the alternating current to the electric vehicle in response to the request to heat the battery pack.

[0079] Figure 3 is a graph showing the heating performance related to various heating methods. For example, Figure 3 shows the heating performance of the battery pack 104 under the following three methods, with an ambient temperature of -20°C and an initial temperature of -15°C for the battery pack 104.

[0080] In some examples, the first method, namely the drive inverter (DI) waste heating, takes approximately 75 minutes to heat the battery pack 104. The second method, namely DI waste heating combined with a heat pump, reduces the heating time to approximately 55 minutes. The third method is DI waste heating combined with a heat pump and using alternating current generated by the charger 200 based on a request from the BMS 102, significantly reducing the heating time to approximately 21 minutes. In some examples, the alternating current used in the third method for heating the battery pack 104 has an amplitude of 360A and a frequency of 100Hz.

[0081] Figure 3 demonstrates that the fastest heating performance of the three methods is achieved by heating the battery pack 104 in Figure 1A using the AC current required by the BMS 102 in Figure 1A and generated by the charger 200 in Figure 2, reaching the desired temperature in the shortest time. This highlights the desirable efficiency and effectiveness of the disclosed system and method for rapidly heating the battery pack 104 in Figure 1A under low ambient conditions.

[0082] FIG. 4 is a schematic diagram of components of a charger (e.g., charger 200) for charging an electric vehicle (e.g., electric vehicle 100) according to some embodiments. As shown in FIG. 4, a plurality of DC-DC converters (e.g., the DC-DC converters of DC-DC converter sets 212A, 212B, 212C, and / or 212D) that supply power to each charger post (e.g., charger posts 202A, 202B, 202C, 202D of FIG. 2) are arranged in parallel with each other. The DC-DC converter can force the high-voltage side current to be in-phase to generate a medium-voltage side AC current. Due to the relatively low control bandwidth, an AC-DC converter (not shown in FIG. 4) such as the AC-DC power stage 208 of FIG. 2 typically only processes DC power and losses and does not typically process AC power for AC heating. In some examples, the AC power circulates through the high-voltage capacitor C hv The total high-voltage side current i hv,total may lag the voltage v hv of the capacitor C hv by 90 degrees. The total high-voltage side current i hv,total can be the sum (e.g., vector addition) of the individual high-voltage side post currents i hv,post1 ~i hv,post4 . As described above, in some embodiments, the outputs generated by each of the DC-DC converters within a DC-DC converter set (e.g., DC-DC converter 212A) can be synchronized and constructively added. In some embodiments, the input currents (e.g., i hv,post1 and i hv,post3 ) to different DC-DC converter sets may be phase-shifted to avoid overloading the capacitor C hv .

[0083] FIG. 5 is a graph of the phase of the current with respect to the charger post of the charger of FIG. 4 and the phase of the high voltage (e.g., V hvbus ) on the bus of the charger of FIG. 4. This graph shows the voltage post currents that are phase-locked (e.g., having the same phase), the current i post1 of charger post 202A of FIG. 2, and the current i post2This graph shows the mid-voltage side current i having the same phase across charger posts 202A, 202B, 202C, and 202D in Figure 2. mv Corresponding to the DC-DC converter set of the charger post in Figure 4 which locks to generate the medium voltage side current i mv The phase is high voltage v hv It is rotated 90 degrees relative to it. Total high voltage side current i hv,total The individual high-voltage side post current i hv,post1 ~i hv,post4 It can be expressed as the sum of the high-voltage capacitor C. hv The rating (for example, approximately 150A) is the total medium voltage side current I MV (For example, i mv,post 1 +i mv,post 2 +i mv,post 3 +i mv,post4 The ripple capability can be limited to the maximum ripple current (e.g., 500A).

[0084] Figure 6 is a schematic diagram of the components of the charger in Figure 4 (e.g., control system 600) for controlling AC ripple across multiple DC-DC voltage converters (e.g., DC-DC converters of DC-DC converter set 212A, 212B, 212C, and / or 212D) according to several embodiments. As shown in Figure 6, the components for controlling AC ripple across multiple DC-DC voltage converters may include a root mean square (RMS) calculator 602A, an RMS calculator 602B, an adder 604A, an adder 604B, a proportional controller 606A, a proportional controller 606B, a comparator 608, a proportional-integral controller 610, a phase-locked loop (PLL) 612, and a control signal generator 614.

[0085] In some examples, RMS calculators 602A and 602B can calculate the root mean square value of their respective input signals. The proportional controller 606A can adjust the response of the control system 600 based on the output of adder 604A (e.g., the difference between two input signals). The proportional controller 606B can adjust the response of the control system 600 based on the output of adder 604B (e.g., the difference between two input signals). The comparator 608 can take the minimum value between the outputs of proportional controllers 606A and 606B. The proportional-integral controller 610 can eliminate steady-state errors and improve the stability of the control system 600. The PLL 612 can be used to synchronize the phases locked by the control system 600. The control signal generator 614 processes the input signal to generate a ripple command signal (e.g., I ripple,cmd It can generate ).

[0086] The control method in Figure 6 can correspond to the phase-locked charger post current as shown in Figure 5. All DC-DC converter sets 212A-212D on charger posts 202A-202D of cabinet 204 can be locked in the same phase (e.g., -90 degrees) with respect to the ripple of the high-voltage bus 250. The high voltage (e.g., v*) on each of the DC-DC converter sets 212A-212D can be locked in the same phase (e.g., v*) hv,meas ) and medium voltage (e.g., v* mv,meas The bus ripple controller limits the maximum ripple on any port (for example, I ripple,cmd This can be done using ( ). When multiple posts merge, if the high-voltage bus ripple exceeds a threshold, the current can be automatically derated (shared proportionally among the posts). The peak ripple current on a post can be clamped to the level required by the vehicle (e.g., electric vehicle 100), and any remaining capacity can be shared among one or more other posts.

[0087] The foregoing disclosure is not intended to limit this disclosure to the exact form or specific field of use disclosed. Therefore, various alternative embodiments and / or modifications to this disclosure, whether expressly described or implied herein, are possible in light of this disclosure. While embodiments of this disclosure have been described in this manner, those skilled in the art will recognize that modifications in form and detail can be made without departing from the scope of this disclosure. Therefore, this disclosure is limited solely by the claims.

[0088] The above specification has described the present disclosure with reference to specific embodiments. However, as those skilled in the art will understand, the various embodiments disclosed herein can be modified or implemented in various other ways without departing from the spirit and scope of the disclosure. Therefore, this description should be considered illustrative and is intended to teach those skilled in the art how to create and use various embodiments of the disclosed display assemblies.

[0089] It should be understood that the forms of disclosure shown and described herein should be interpreted as representative embodiments. Equivalent elements, materials, processes, or steps may be substituted for those representatively shown and described herein. Furthermore, certain features of this disclosure may be used independently of the use of other features, as will become apparent to those skilled in the art after benefiting from this description of the disclosure. Expressions such as “including,” “comprising,” “incorporating,” “consisting of,” “have,” and “is” used to describe and claim this disclosure are intended to be interpreted in a non-exclusive manner, that is, to allow for the existence of items, components, or elements not expressly described. Singular references should also be interpreted in relation to plurals. Furthermore, the various embodiments disclosed herein should be interpreted in an illustrative and descriptive sense and should not be interpreted in any way as limiting this disclosure.

[0090] All references to connections (e.g., mounting, fastening, joining, connecting, etc.) are used solely to aid the reader's understanding of this disclosure and do not imply any limitation with respect to the location, orientation, or use of the systems and / or methods disclosed herein. Therefore, where there is a reference to a connection, it should be interpreted broadly. Furthermore, such references to connections do not necessarily imply that the two elements are directly connected to each other. Additionally, but not limited to, all numerical terms such as “first,” “second,” “third,” “principal,” “secondary,” “main,” or any other common and / or numerical terms should also be interpreted solely as identifiers to aid the reader's understanding of the various elements, embodiments, variations, and / or modifications of this disclosure, and in particular, do not imply any limitation with respect to the order or preference of any element, embodiment, variation, and / or modification of another element, embodiment, variation, and / or modification, or beyond.

[0091] The exemplary algorithms described in relation to the embodiments disclosed herein can be implemented as electronic hardware (e.g., ASIC or FPGA devices), computer software running on computer hardware, or a combination of both. Furthermore, the various exemplary logic blocks and modules described in relation to the embodiments disclosed herein can be implemented or executed by machines such as processor devices, digital signal processors ("DSPs"), application-specific integrated circuits ("ASICs"), field-programmable gate arrays ("FPGAs") or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. The processor device may be a microprocessor, but in alternative examples, the processor device may be a controller, microcontroller, or state machine, or a combination thereof. The processor device may include electrical circuits configured to process computer-executable instructions. In another embodiment, the processor device includes an FPGA or other programmable device that performs logical operations without processing computer-executable instructions. The processor device can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration. Although this specification primarily describes digital technologies, processor devices may also include primarily analog components. For example, some or all of the rendering techniques described herein can be implemented in analog circuits or mixed analog-digital circuits. Computing environments may include, but are not limited to, any type of computer system based on a microprocessor, mainframe computer, digital signal processor, portable computing device, device controller, or in-device computing engine, to name a few.

[0092] It will also be understood that, depending on the specific application, one or more of the elements shown in the drawings / figures may also be implemented in a more separated or integrated manner, or in certain cases may be removed or depicted as non-functional.

Claims

1. A system for managing the battery pack of an electric vehicle, A sensor configured to detect the temperature related to the battery pack, A controller that communicates with the aforementioned sensor, wherein the controller Based on the sensor signal from the aforementioned sensor, a request is sent to the charger. A controller configured to supply at least a portion of the alternating current received from the charger to at least the first battery cell of the battery pack, such that heat is generated based on the internal resistance of the first battery cell in order to raise the temperature associated with the first battery cell, A system equipped with these features.

2. The system according to claim 1, wherein the controller is configured to transmit the request to the charger in response to determining, based on the sensor signal, that the temperature associated with the battery pack meets a threshold.

3. The system according to claim 1, wherein the requirement specifies at least one of the amplitude, frequency, or direct current (DC) offset of the alternating current.

4. The system according to claim 3, wherein the controller is configured to determine at least one of the amplitude, frequency, or DC offset based on at least one of the cell type of the battery pack, the temperature associated with the battery pack, or the charge state of the battery pack.

5. The system according to claim 1, wherein the frequency of the alternating current is within the range of 80 hertz (Hz) to 500 Hz.

6. The system according to claim 1, wherein the amplitude of the alternating current is in the range of 100 amperes to 1000 amperes.

7. The system according to claim 1, wherein the controller is configured to monitor the AC and to transmit updated requests based on the monitoring of the AC.

8. It is an electric vehicle, Multiple battery cells, including a first battery cell, A battery management system, wherein the battery management system is The state related to the plurality of battery cells is detected, In response to the detection of the aforementioned state, a request is sent to the charger. A battery management system configured to supply AC to at least the first battery cell in relation to the request and received from the charger such that the internal resistance of the first battery cell and the AC increase the temperature associated with the first battery cell, An electric vehicle equipped with [a specific feature].

9. The electric vehicle according to claim 8, wherein the state includes at least one of the temperature associated with the plurality of battery cells, the charge state of the plurality of battery cells, or the cell type of the plurality of battery cells.

10. The electric vehicle according to claim 8, wherein the requirement specifies the DC offset of the alternating current, and the battery management system determines the DC offset based at least in part on the temperature associated with the plurality of battery cells.

11. The electric vehicle according to claim 10, wherein the battery management system is configured to supply the AC current to the plurality of battery cells in order to charge at least one of the plurality of battery cells.

12. The electric vehicle according to claim 10, further comprising one or more other components, wherein the battery management system supplies alternating current for powering the one or more other components, and the one or more other components comprises at least one of a drive unit, a compressor, or a power conversion system.

13. The electric vehicle according to claim 8, wherein the requirement specifies the amplitude and DC offset of the AC, and the battery management system is configured to determine the amplitude and DC offset based at least in part on the state.

14. The aforementioned battery management system To generate a monitoring signal, the amplitude of the AC is monitored, Based on the monitoring signal, an updated request is generated to adjust the amplitude of the AC. The electric vehicle according to claim 8, configured to transmit the updated request to the charger.

15. A method for managing battery packs, A step of detecting the temperature related to the battery pack, The steps include sending a request to the charger to identify the AC waveform based on the temperature, The steps include supplying at least a portion of the alternating current associated with the request received from the charger to at least the first battery cell of the battery pack such that heat is generated based on the internal resistance of the first battery cell in order to raise the temperature associated with the first battery cell, Methods that include...

16. A step of monitoring the amplitude of the AC in order to generate a monitoring signal, The steps include generating an updated request to adjust the amplitude of the AC based on the monitoring signal and sending it to the charger, The method according to claim 15, further comprising:

17. The process further includes determining whether the temperature associated with the battery pack meets a threshold, The method of claim 15, wherein the request is transmitted in response to a determination that the temperature associated with the battery pack satisfies the threshold.

18. The steps further include determining amplitude, frequency, and DC offset based on at least one of the cell type of the battery pack, the temperature associated with the battery pack, and the charge state of the battery pack, The method according to claim 15, wherein the AC waveform represents the amplitude, frequency, and DC offset.

19. The method according to claim 15, further comprising the step of supplying the alternating current to power a drive unit, compressor, or power conversion system of an electric vehicle.

20. The method according to claim 15, wherein the frequency of the AC is 80 Hz to 500 Hz.

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