Alternating current cell heating

Abstract

Embodiments of the present disclosure relate to alternating current cell heating. A system for managing a battery pack of an electric vehicle includes a sensor and a controller. The sensor is configured to detect a temperature associated with the battery pack. The controller is configured to send a request to the charger based on a sensor signal from the sensor and provide at least a portion of an alternating current 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 increase a temperature associated with the first battery cell. Related electric vehicles, methods, and chargers are disclosed.

Description

Cross-reference to related applications

[0001] This application claims priority to U.S. Patent Application No. 19 / 244520, entitled "ALTERNATING CURRENT BATTERY HEATING", filed June 20, 2025, and U.S. Provisional Patent Application No. 63 / 717,719, entitled "ALTERNATING CURRENT BATTERY HEATING", filed November 7, 2024, the entire disclosure of which is incorporated herein by reference and used for all purposes. Technical Field

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

[0003] Electric vehicles experience reduced performance in cold weather. For example, the battery packs used in electric vehicles may face challenges when charging at low temperatures (e.g., below 0°C). Under certain low-temperature conditions, vehicles may be unable to charge their battery packs, potentially leading to excessively long waiting times at charging stations and even complete power loss in some vehicles. Furthermore, charging at low temperatures can cause battery cell degradation and lithium plating, which can affect the lifespan and performance of the energy storage system. Summary of the Invention

[0004] The systems, methods, and apparatuses disclosed herein have several innovative embodiments, none of which alone is responsible for all the desired properties disclosed herein. Details of one or more implementations of the subject matter described herein are set forth in the accompanying drawings and the following description.

[0005] In some aspects, 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 in communication with the sensor, the controller being configured to: send a request to a charger based on a sensor signal from the sensor, the request identifying an alternating current waveform; and provide at least a portion of the alternating current 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 increase the temperature associated with the first battery cell.

[0006] In some respects, the techniques described herein relate to a system in which a controller is configured to send the request to a charger in response to determining, based on sensor signals, that a temperature threshold associated with the battery pack has been met.

[0007] In some respects, the techniques described herein relate to a system in which the request specifies at least one of the amplitude, frequency, or direct current (DC) offset of the alternating current.

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

[0009] In some respects, the techniques described herein relate to a system in which the frequency of alternating current is in the range of 80 Hz to 500 Hz.

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

[0011] In some respects, the techniques described herein relate to a system in which a controller is configured to monitor alternating current and send updated requests based on the monitored alternating current.

[0012] In some aspects, the technology described herein relates to an electric vehicle comprising: a plurality of battery cells including a first battery cell; and a battery management system configured to: detect a condition associated with the plurality of battery cells; in response to detecting the condition, send a request to a charger; and provide at least a portion of an alternating current associated with the request and received from the charger to at least the first battery cell, such that the internal resistance of the first battery cell and the alternating current increase the temperature associated with the first battery cell.

[0013] In some respects, the technology described herein relates to electric vehicles, wherein the condition includes at least one of the following: temperature associated with multiple battery cells, state of charge of multiple battery cells, or battery type of multiple battery cells.

[0014] In some respects, the techniques described herein relate to electric vehicles, wherein the request specifies a direct current (DC) offset of the alternating current, and wherein the battery management system determines the DC offset based at least in part on the temperature associated with multiple battery cells.

[0015] In some respects, the technology described herein relates to electric vehicles in which a battery management system is configured to provide alternating current to a plurality of battery cells to charge at least one of the plurality of battery cells.

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

[0017] In some respects, the techniques described herein relate to electric vehicles, wherein the request specifies the magnitude and DC offset of the alternating current, and wherein the battery management system is configured to determine the magnitude and DC offset based at least in part on the conditions.

[0018] In some respects, the technology described herein relates to electric vehicles, wherein a battery management system is configured to: monitor the amplitude of an alternating current to generate a monitoring signal; generate an updated request based on the monitoring signal for adjusting the amplitude of the alternating current; and send the updated request to a charger.

[0019] In some respects, the technology described herein relates to a method for managing a battery pack, the method comprising: detecting a temperature associated with the battery pack; sending a request to a charger based on the temperature, the request identifying an alternating current waveform; and providing an alternating current 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 increase the temperature associated with the first battery cell.

[0020] In some respects, the techniques described herein relate to a method that further includes: monitoring the amplitude of an alternating current to generate a monitoring signal; and generating, based on the monitoring signal, an updated request for adjusting the amplitude of the alternating current and sending it to a charger.

[0021] In some respects, the techniques described herein relate to a method that further includes: determining a temperature satisfaction threshold associated with a battery pack, wherein the request is sent in response to determining the temperature satisfaction threshold associated with the battery pack.

[0022] In some respects, the techniques described herein relate to a method that further includes determining amplitude, frequency, and DC offset based on at least one of the battery type of the battery pack, the temperature associated with the battery pack, and the state of charge of the battery pack, wherein the alternating current waveform indicates the amplitude, frequency, and DC offset.

[0023] In some respects, the techniques described herein relate to a method that also includes providing alternating current to power the drive unit, compressor, or power conversion system of an electric vehicle.

[0024] In some respects, the techniques described herein involve a method in which the frequency of the alternating current is between 80 Hz and 500 Hz.

[0025] In some aspects, 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 and send an alternating current to the electric vehicle based on control signals; and a controller in communication with the plurality of voltage converters, the controller being configured to: receive a request from the electric vehicle associated with heating the battery pack; generate and send control signals to the plurality of voltage converters in response to the request; and cause the plurality of voltage converters to send an alternating current associated with the request to the electric vehicle to heat the battery pack. Attached Figure Description

[0026] Embodiments of this disclosure are described with reference to the accompanying drawings, wherein like reference numerals denote like elements, and in the figures:

[0027] Figure 1A This is an example schematic diagram of the components of an example vehicle in which embodiments of the present disclosure may be implemented;

[0028] Figure 1B According to some embodiments of this disclosure Figure 1A Example illustration of an example vehicle;

[0029] Figure 2 This is a schematic diagram of the components of an example charger in which embodiments of the present disclosure may be implemented;

[0030] Figure 3 It is a graph showing the heating performance in relation to various heating methods;

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

[0032] Figure 5 Is with Figure 4 The phase of the high voltage on the charger bus is compared to... Figure 4 A phase diagram of the current at the charger's charging pile; and

[0033] Figure 6 According to some embodiments Figure 4 A schematic diagram of a charger component used to control the alternating current (AC) ripple across multiple DC-DC voltage converters. Detailed Implementation

[0034] The following description of certain embodiments presents various descriptions of specific embodiments. However, the innovations described herein can be embodied in many different ways, for example, as defined and covered by the claims. In this specification, reference is made to the accompanying drawings, wherein the same reference numerals may denote the same or functionally similar elements. It should be understood that the elements shown in the drawings are not necessarily drawn to scale. Furthermore, it should be understood that some embodiments may include more elements and / or a subset of the elements shown in the figures than are shown in the figures. Additionally, some embodiments may combine any suitable combination of features from two or more figures. Any suitable principles and advantages of the embodiments disclosed herein may be realized together with each other.

[0035] In general, one or more aspects of this disclosure relate to methods and systems for heating a battery pack in an electric vehicle using alternating current (AC). This heating can improve charging performance in cold weather conditions. As used herein, the AC current can include currents in the form of sine waves, pulses, ripples, square waves, sawtooth waves, etc. Some embodiments of this disclosure relate to a charging system (e.g., a system that may include components in a charger and components in a vehicle) that utilizes the internal resistance of the battery cells in the battery pack to generate heat to heat the battery pack by providing an AC current from a charger (e.g., a charging station) through the vehicle's charging port. The provided AC current can be a signal (e.g., an electrical signal) that can be described using various types of signal waveforms (e.g., sine waves, square waves, sawtooth waves, pulses, ripples, etc.). The AC current can have a DC offset (e.g., a offset from the baseline of the AC signal). For example, an AC current with a DC offset can oscillate near a non-zero baseline instead of near zero.

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

[0037] Advantageously, by utilizing alternating current to generate heat from the internal resistance of the battery cells, the charging system can heat the battery cells more effectively and achieve higher energy efficiency and faster heating compared to some other methods. For example, the disclosed alternating current heating method can achieve an efficiency of over 90%, while some coolant-based heating methods have efficiencies below 50%. The improved efficiency of alternating current heating is likely due to reduced losses in conducting alternating current to the battery cells and direct heat generation within the battery cells, which reduces thermal barriers and heat losses. Advantageously, even under extremely cold conditions, the charging system can quickly bring the battery pack to a better or optimal charging temperature. This rapid heating capability allows the vehicle to be charged in a relatively short time (e.g., within 15 minutes at an ambient temperature of -20°C).

[0038] The charging system can leverage existing hardware on electric vehicles and chargers, enabling relatively low-cost and / or retrofit implementation within existing 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 requested AC current (e.g., AC current with amplitude, frequency, and / or DC offset specified by the electric vehicle) for the electric vehicle. On the electric vehicle side, the charging system can utilize existing hardware associated with the charging ports and BMS, and control (e.g., via updated firmware) existing hardware to achieve battery heating. By enabling rapid heating of the battery pack, the charging system can significantly improve the overall charging speed of vehicles and the throughput of charging stations. This can reduce customer wait times and improve 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 vary in power levels, ranging from relatively slow chargers using standard household outlets to relatively fast chargers or charging stations that can charge EV batteries in significantly shorter times. The task of a charging system is to provide efficient, safe, and reliable energy transfer to the vehicle's battery pack to ensure EVs are always available.

[0040] One technological challenge in electric vehicle charging is efficiently charging battery packs in cold weather. Lithium-ion batteries, widely used in EVs, have limited capacity to accept charge at temperatures below 0°C. Charging at such low temperatures can also lead to battery degradation and lithium plating, affecting battery performance and lifespan. Furthermore, vehicles may be unable to charge at low temperatures. This can result in excessively long waiting times at charging stations, and in some cases, vehicles may be completely disconnected from the power supply.

[0041] Some technical solutions for charging battery packs in cold weather involve using heat generated outside the battery pack to heat it. For example, some systems use heated coolant to heat the battery pack. This approach may involve circulating a heated fluid through the battery pack to raise its temperature. However, due to thermal barriers and heat losses, the efficiency of this approach may be less than 50%. Furthermore, the performance of heat pumps, which can be used in conjunction with coolant-based heating, may degrade significantly at low temperatures because there may be no source of ambient heat.

[0042] To address at least some of the aforementioned problems, some embodiments of this disclosure relate to a charging system that utilizes the internal resistance of the battery cells in a battery pack to heat the battery pack by providing alternating current from a charger to the battery cells through a charging port. In some embodiments, when the BMS of an electric vehicle determines that the battery pack needs to be heated, the BMS sends a request to the charger (such as a charging station) to heat the battery pack. For example, the BMS may determine to heat the battery pack in response to detecting that the temperature of the battery pack is below a threshold and / or in response to detecting one or more other conditions (e.g., frost or ice buildup on the battery pack, weather such as a blizzard).

[0043] The request may specify one or more parameters (e.g., amplitude, frequency, DC offset, type associated with the battery cell, etc.) associated with the AC current to be generated by the charger and injected from the charger. In some embodiments, the BMS may determine the amplitude, frequency, and DC offset associated with the AC current based on one or more of the battery cell type, the temperature associated with the battery pack, the state of charge 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 current to accelerate the heating process compared to a case where the battery pack temperature is higher (e.g., around -5°C). As another example, when the temperature associated with the battery pack is above 0°C, the BMS can determine that the battery pack can be charged using DC power. In this example, the BMS can request to generate an AC current with a specific offset value (multiple of these offsets) 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 current to power other components, power from the battery pack can be omitted.

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

[0046] In response to receiving the request, the charger can generate an alternating current based on the request. This alternating current can be provided to the charging port of the electric vehicle and then flows into the battery pack to heat the battery pack before and / or during charging (e.g., using 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 alternating current to provide to the electric vehicle and / or inject into the battery pack. For example, the charger can include multiple (e.g., four) DC-DC converter groups, where each DC-DC converter group can include one or more (e.g., four) DC-DC converters capable of generating an AC waveform. Each DC-DC converter group can convert signals(s) on a high-voltage DC bus (e.g., about 900 volts) into the desired AC waveform. The DC-DC converter groups can be configured to generate an AC waveform according to a specified amplitude, frequency, and DC offset based on a request from the electric vehicle's BMS. In some embodiments, each DC-DC converter in the DC-DC converter group can generate a portion of the alternating current to be provided to the battery pack. Individual AC waveforms generated by the DC-DC converters in the DC-DC converter group can be phase-aligned and frequency-aligned, allowing the individual AC waveforms to be added together to generate the requested AC current. In some embodiments, the amplitude of the AC current can be distributed among the DC-DC converters in the DC-DC converter group. In some embodiments, if the vehicle requests an AC current of 400 amps (A) and there are four DC-DC converters in the DC-DC converter group, each DC-DC converter in the DC-DC converter group can generate an AC waveform of 100A.

[0047] In some embodiments, the charger can monitor signals on the high-voltage DC bus and / or signals output by the DC-DC converter group to maintain synchronization between AC waveforms generated by the DC-DC converters in the DC-DC converter group 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 group. Instead, the charger can monitor the voltage on the high-voltage DC bus and / or the AC waveforms generated by each DC-DC converter group to maintain synchronization (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 any abnormal or excessive current flowing through capacitors connected to the high-voltage DC bus and supplying current to the DC-DC converter group. Therefore, the capacitors are not damaged or overstressed.

[0048] Additionally and / or alternatively, to avoid stressing or damaging the capacitors supplying current to the DC-DC converter banks, the input signals (e.g., input voltage or current) of at least some of the DC-DC converter banks can be controlled to be out of phase with each other. For example, instead of supplying four in-phase input signals to each group of four DC-DC converter banks, two groups of four DC-DC converter banks can receive input signals in a first phase, and another two groups of four DC-DC converter banks can receive input signals in a second phase opposite to the first phase. As another example, the input signals of the DC-DC converter banks can be out of phase with the other input signals of other DC-DC converter banks. By alternatively avoiding supplying all in-phase signals to the DC-DC converter banks, the charger can reduce stress on the capacitors. This can prevent or avoid subjecting the capacitors to excessive stress.

[0049] During the period when the battery pack is being heated, the BMS of the electric vehicle can monitor the heating process and adjust parameters (e.g., amplitude, frequency, DC offset, etc.) based on the monitoring results. The BMS can adjust one or more parameters dynamically and / or periodically. In some embodiments, the BMS can monitor the amplitude, frequency, and / or DC offset of the AC current received from the charger and compare the monitored amplitude, frequency, and / or DC offset with a request made by the BMS. For example, if the BMS determines that the amplitude of the AC current is less 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 amplitude. On the other hand, if the BMS determines that the amplitude of the AC current is higher than the requested amplitude or above an appropriate level, the BMS can send an updated request to request the charger to reduce the amplitude of the AC current.

[0050] As described above, the BMS can request an AC current with a DC offset. In some embodiments, during heating, the BMS can also distribute the AC 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., >0°C), the BMS can allow the supply of an AC current with a DC offset to the battery pack. Thus, the AC component of the AC current can be used to heat the battery pack, and the DC component of the AC current can be used to charge the battery. On the other hand, if the BMS determines that the temperature of the battery pack is below a threshold, the BMS can separate (e.g., using filtering techniques) the AC and DC components of the AC current. For example, the BMS can allow only the AC component to be supplied to the battery pack to heat it, and can utilize the DC component of the AC current 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 employ one or more control algorithms to manage the allocation of AC and DC components. For example, based on the battery pack's temperature, state of charge, and / or other factors, the BMS may determine how much AC component should be used for heating and how much DC component should be used for charging. Advantageously, the control algorithm can ensure that the battery pack is heated efficiently without affecting the charging process. Additionally and / or alternatively, 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. As described above, in addition to regulating the heating and charging of the battery pack, the BMS may also allocate 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 may be used to power heating, ventilation, and air conditioning (HVAC) systems, drive units, and / or other high-voltage equipment, while the AC and DC components may be used to charge and heat the battery pack. This allocation allows all vehicle systems to operate efficiently and effectively.

[0052] The foregoing aspects and many advantages thereof will be more readily understood when taken in conjunction with the accompanying drawings and by reference to the following description.

[0053] Figure 1A This is an example schematic block diagram of components of an example electric vehicle 100 in which embodiments of the present disclosure may be implemented. Figure 1AAs shown, the electric vehicle 100 includes a battery pack 104, a battery management system (BMS) 102, a charging port 106, a power conversion system 108, a compressor 110, a drive unit 112, and an internal low-voltage unit (LV) 114. The electric vehicle 100 also includes a coolant circuit capable of heating and cooling the battery pack 104. It should be noted that although the BMS 102 is illustrated as part of the battery pack 104, in some other embodiments, the BMS 102 may be separate from or located outside the battery pack 104.

[0054] Battery pack 104 may include multiple lithium-ion battery cells for storing electrical energy for the vehicle. As described above, when an alternating current is applied, the internal resistance of the battery cells can be used to generate heat, thereby heating the battery cells from the inside. For example, the resistance of a jelly roll generates heat within the battery cell. BMS 102 may be or include an electrical control unit (ECU) associated with the battery pack. BMS 102 may include any suitable circuitry for performing the functions of the BMS disclosed herein. Advantageously, utilizing alternating current and the internal resistance of the battery cells allows for the uniform and / or efficient generation of heat within the battery cells. Whenever current passes through the battery cell, the internal resistance causes heating without damaging the battery cell. Furthermore, heating can occur more quickly compared to other methods, such as using a heat pump or cooling, resistance heating, or other heating mechanisms from outside the battery cell.

[0055] The power conversion system 108 can convert power from a charger (e.g., Figure 2 The electrical energy from the charger 200 is converted into a form usable by the battery pack 104 and / or other high-voltage (HV) equipment 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 passenger compartment of the electric vehicle 100. The drive unit 112 may include an electric motor and related components that provide propulsion to the electric vehicle 100. The internal low-voltage (LV) system 114 may refer to the low-voltage electrical system within the electric vehicle 100 that supplies power to various auxiliary devices and systems. The power conversion system 108 can generate power for the internal LV system 114.

[0056] Charging port 106 can be an interface through which electric vehicle 100 connects to charger 200. Charging port 106 facilitates the transfer of electrical energy from charger 200 to battery pack 104 and other components. Charging port 106 can also serve as a communication link between electric vehicle 100 and charger 200 to facilitate the transmission of requests from BMS 102 for alternating current to heat battery pack 104. In this case, electronic control unit (ECU) 116 of charging port 106 can facilitate such requests. ECU 116 of charging port 106 can transmit the request to… Figure 2The charging station 202's station controller, and the station controller can transmit the request to... Figure 2 Busbar controller 210. Figure 2 The bus controller 210 can control Figure 2 The DC-DC converter group 212A, 212B, 212C and / or 212D generates AC current for battery heating. In some applications, requests from BMS 102 can be wirelessly sent to... Figure 2 The charger is 200.

[0057] In some embodiments, when BMS 102 determines that battery pack 104 needs to be heated, BMS 102 may send a request to charger 200 to heat battery pack 104. In some applications, this request may be sent to charger 200 via charging port 106. For example, BMS 102 may determine to heat battery pack 104 in response to detecting that the temperature of battery pack 104 is below a threshold and / or detecting one or more other conditions (e.g., frost or ice buildup on the battery pack, blizzard weather, etc.).

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

[0059] For example, if the temperature associated with battery pack 104 is very low (e.g., below -20°C), BMS 102 may request a higher amplitude AC current to accelerate the heating process compared to a higher temperature associated with battery pack 104 (e.g., approximately -5°C). As another example, when the temperature associated with battery pack 104 is above 0°C, BMS 102 can determine that battery pack 104 can be charged using DC power. In this example, BMS 102 may request the generation of AC current with a specific offset value (multiple of these offsets) to power AC current without a DC offset, which may depend on the rate at which battery pack 104 is charged using DC power. As yet another example, BMS 102 may request the generation of AC current with a DC offset to power other components of electric vehicle 100 (e.g., drive unit 112, compressor 110, power conversion system 108, etc.), regardless of the temperature of battery pack 104.

[0060] In some embodiments, BMS 102 may request an AC current with a frequency in any other suitable range between 80Hz and 320Hz, 100Hz and 200Hz, 100Hz and 500Hz, or 80Hz and 500Hz. In some embodiments, BMS 102 may request an AC current with an amplitude in any other suitable range between 600A and 1000A, 200A and 900A, 300A and 800A, 100A and 700A, and / or 100A and 1000A.

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

[0062] Then, from Figure 2 The alternating current received by the charger 200 can be used to charge the battery pack 104. During the period when the battery pack 104 is being heated, the BMS 102 can monitor the heating process and adjust parameters (e.g., amplitude, frequency, DC offset, etc.) based on the monitoring results. These parameters can be dynamically adjusted. These parameters can be adjusted periodically. In some embodiments, the BMS 102 can monitor one or more of the amplitude, frequency, or DC offset of the alternating current received from the charger 200 and compare the monitored amplitude, frequency, and / or DC offset with a request made by the BMS 102. For example, if the BMS 102 determines that the amplitude of the alternating current is less than the requested amplitude, the BMS 102 can send an updated request to the charger 200. The updated request can request a higher amplitude compared to the previously requested amplitude. On the other hand, if the BMS 102 determines that the amplitude of the alternating current is higher than the requested amplitude or higher than an appropriate level, the BMS 102 can send an updated request to request the charger 200 to reduce the amplitude of the alternating current.

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

[0064] In some embodiments, BMS 102 may employ one or more control algorithms to manage the allocation of AC and DC components. For example, based on the battery pack temperature, state of charge, and / or other factors, BMS 102 may determine how much AC component will be used for heating and how much DC component will be used for charging. Advantageously, the control algorithm may ensure that the battery pack 104 is heated efficiently without affecting the charging process. Additionally and / or alternatively, BMS 102 may 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, BMS 102 may 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. As described above, in addition to regulating the heating and charging of the battery pack 104, BMS 102 may also allocate the AC and DC components of the alternating current from charger 200 to one or more other auxiliary loads within the electric vehicle. For example, some DC components can be used to power one or more of the heating, ventilation, and air conditioning (HVAC) system, compressor 110, drive unit 112, or one or more other high-voltage devices, while AC components and some DC components can be used to charge and heat the battery pack 104. This allocation allows all vehicle systems to operate efficiently and effectively.

[0065] Figure 1B According to some embodiments of this disclosure Figure 1A Example schematic diagram of electric vehicle 100. Figure 1BAs shown, the electric vehicle 100 may include a battery pack 104, a controller 140, a sensor 150, and a component 160. In some examples, the controller 140 may include or implement Figure 1A BMS 102. For example, controller 140 may include any suitable hardware (e.g., processor and memory) to implement the reference. Figure 1A The functions described in BMS 102. Component 160 may include power conversion system 108, compressor 110, drive unit 112, or other components associated with electric vehicle 100.

[0066] In some embodiments, sensor 150 is configured to detect the temperature associated with battery pack 104. Sensor 150 may be a thermistor, thermocouple, resistance temperature detector, infrared sensor, semiconductor temperature sensor, etc. Controller 140 may communicate with sensor 150. Controller 140 may send signals to the charger (e.g., referencing the sensor signal from sensor 150) based on the sensor signal from sensor 150. Figure 2 The charger 200 sends a request. This request may identify an AC current waveform for which the charger will generate an AC current. The controller 140 may provide the AC current associated with the request and received from the charger to at least a first battery cell of the battery pack 104, such that heat is generated based on the internal resistance of the first battery cell to increase the temperature associated with the first battery cell.

[0067] Figure 2 This is a schematic diagram of the components of a charger 200 in which embodiments of the present disclosure may be implemented. (See diagram for reference.) Figure 2 As shown, charger 200 includes at least a charging pile 202A, a charging cabinet 204, and a site manager controller 206. The charging cabinet 204 includes an AC-DC power stage 208, a bus controller 210, and DC-DC converter groups 212A, 212B, 212C, and 212D. As described above, charger 200 can generate AC current for heating the battery pack 104 of electric vehicle 100. Charger 200 can also generate AC current for charging / powering one or more other components of electric vehicle 100. Charger 200 may be, for example, a Tesla Supercharger. In some embodiments, charger 200 and at least some portions of electric vehicle 100 can form a charging system for charging and / or heating the battery pack.

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

[0069] Charger station 202 can be used as Figure 1A The charging station 202 is the physical interface between the electric vehicle 100 and the charger 200. The charging station 202 may house connectors and cables that facilitate the transfer of electrical energy from the charger 200 to the electric vehicle 100. The charging station 202 may also include one or more communication interfaces that allow the electric vehicle 100 (e.g., BMS 102) to send requests to heat the battery pack and receive responses from the charger 200.

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

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

[0072] The AC-DC power stage 208 of the charger cabinet 204 converts 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, which can be used as input to the DC-DC converter groups 212A, 212B, 212C, and 212D. The AC-DC power stage 208 ensures a stable voltage signal on the high-voltage DC bus 250 and supplies power for heating the battery pack 104. The AC-DC power stage 208 can include five AC-DC power stages.

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

[0074] DC-DC converter groups 212A, 212B, 212C, and 212D may include any suitable DC-DC converter that can convert a signal on the high-voltage DC bus 250 into alternating current for heating the battery pack 104. Each of the DC-DC converter groups 212A, 212B, 212C, and 212D may include one or more DC-DC converters. As described above and as... Figure 2 As shown, each of the illustrated DC-DC converter groups 212A, 212B, 212C, and 212D includes four DC-DC converters. However, one or more of the DC-DC converter groups 212A, 212B, 212C, and 212D may include other suitable numbers of DC-DC converters. Each DC-DC converter group can be able to generate a portion of the AC current, and the outputs of the DC-DC converters in the DC-DC converter group can be synchronized to constructively add together to achieve the desired amplitude, frequency, and / or DC offset. Furthermore, the DC-DC converter groups 212A, 212B, 212C, and 212D can generate AC currents with different amplitudes, frequencies, and DC offsets, such as... Figure 1A As specified in BMS 102.

[0075] In response to Figure 1AWhen the electric vehicle 100 receives a request to heat the battery pack 104, the charger 200 can generate alternating current based on the request and inject the alternating current. Figure 1A In the battery pack 104, heat is generated before and / or during charging of the battery pack 104 (e.g., using heat generated by the internal resistance of the battery cells of the battery pack 104). As described above, the bus controller 210 can control the AC-DC power stage 208 and the DC-DC converter groups 212A, 212B, 212C, and 212D to generate and synchronize alternating current to be supplied to the battery pack 104. For example, each of the DC-DC converter groups 212A, 212B, 212C, and 212D can convert signals(s) on the high-voltage DC bus 250 into a desired AC waveform. The DC-DC converter groups 212A, 212B, 212C, and 212D can be configured to generate AC waveforms according to specified amplitude, frequency, and DC offset requested by the BMS 102. In some embodiments, each of the DC-DC converter groups 212A, 212B, 212C, and 212D can generate a portion of the AC current to be injected into the battery pack 104. The individual AC waveforms generated by the DC-DC converters in each of the DC-DC converter groups 212A, 212B, 212C, and 212D can be phase-aligned and frequency-aligned, allowing the individual AC waveforms to add constructively rather than cancelably to generate the requested AC current. The amplitude of the AC current can be distributed among the DC-DC converters in the DC-DC converter groups 212A, 212B, 212C, and 212D. For example, if the BMS 102 requests an AC current of 400A from the DC-DC converter group 212A, each DC-DC converter in the DC-DC converter group 212A can generate an AC waveform of 100A.

[0076] In some embodiments, the charger 200 (e.g., bus controller 210) may monitor signals on the high-voltage DC bus 250 and / or signals output by the DC-DC converter groups 212A, 212B, 212C, and 212D to maintain synchronization between the AC waveforms generated by the DC-DC converters of the DC-DC converter groups 212A, 212B, 212C, and 212D and / or protect the components of the charger 200 from damage. More specifically, the bus controller 210 may operate without digital synchronization technology to synchronize the outputs (e.g., current) associated with the DC-DC converter groups 212A, 212B, 212C, and 212D. Instead, each converter group and / or each DC-DC converter in the respective group of the DC-DC converter groups 212A, 212B, 212C, and 212D may monitor the voltage on the high-voltage DC bus 250 to maintain synchronization (e.g., based on the monitored phase and / or frequency of the voltage on the high-voltage DC bus 250). For example, DC-DC converter group 212B can monitor the voltage on high-voltage DC bus 250 to synchronize the DC-DC converters in DC-DC converter group 212B. Each converter group in DC-DC converter groups 212A, 212B, 212C, and 212D can also monitor the voltage ripple amplitude on high-voltage DC bus 250 to ensure that no excessive current flows into and / or out of the capacitors connected to high-voltage DC bus 250. Figure 2 (Not shown in the diagram), this capacitor supplies current to the DC-DC converter groups 212A, 212B, 212C, and 212D. Furthermore, the bus controller 210 can sum the current consumed by each of the DC-DC converter groups 212A, 212B, 212C, and 212D to ensure that the total current consumed by the DC-DC converter groups 212A, 212B, 212C, and 212D is below a maximum limit. Therefore, the capacitor will not be damaged or overstressed.

[0077] Additionally and / or alternatively, to reduce stress on the capacitors supplying current to the DC-DC converter groups 212A, 212B, 212C, and 212D, the input signals (e.g., input voltage or current) of at least some of the DC-DC converter groups 212A, 212B, 212C, and 212D can be controlled to be out of phase with each other. For example, instead of supplying four in-phase input signals to each of the DC-DC converter groups 212A, 212B, 212C, and 212D, DC-DC converter groups 212A and 212B may receive input signals in a first phase, while DC-DC converter groups 212C and 212D may receive input signals in a second phase opposite to the first phase. As another example, each of the DC-DC converter groups 212A, 212B, 212C, and 212D may receive an input signal out of phase with the input signals received by the other DC-DC converter groups. By alternatively avoiding supplying all in-phase signals to the DC-DC converter groups 212A, 212B, 212C, and 212D, the bus controller 210 can prevent capacitor overstress.

[0078] In some embodiments, charger 200 can be used to charge and heat a battery pack of an electric vehicle (e.g., battery pack 104 of electric vehicle 100). Charger 200 may include multiple voltage converters (e.g., a group of DC-DC converters 212A, 212B, 212C, and 212D) and a controller (e.g., a bus controller 210) communicating with the multiple voltage converters. The multiple voltage converters may be configured to generate alternating current based on control signals and to send the alternating current to the electric vehicle. The controller may be configured to receive a request associated with heating the battery pack. In response to the request, the controller may generate control signals and send them to the multiple voltage converters. The controller may cause the multiple voltage converters to send the alternating current associated with the request to the electric vehicle to heat the battery pack.

[0079] Figure 3 This is a graph showing the heating performance in relation to various heating methods. For example, Figure 3 The heating performance of battery pack 104 in relation to three methods is shown at an ambient temperature of -20°C and an initial temperature of -15°C.

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

[0081] Figure 3 This indicates that by using Figure 1A BMS 102 request and by Figure 2 The charger 200 generates AC current to heat Figure 1A The battery pack 104 achieves the fastest heating performance among these three methods, reaching the desired temperature in the shortest time. This highlights the rapid heating capability of the disclosed system and method under cold environmental conditions. Figure 1A The battery pack 104 has ideal efficiency and effectiveness.

[0082] Figure 4 This 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. Figure 4 As shown, to each charging station (e.g., Figure 2 The charging piles 202A, 202B, 202C, and 202D provide power through multiple DC-DC converters (e.g., DC-DC converters in DC-DC converter groups 212A, 212B, 212C, and / or 212D) connected in parallel. The DC-DC converters can force the high-voltage side current to be in phase to generate medium-voltage side AC current. Due to the relatively low control bandwidth, the AC-DC converters ( Figure 4 (not shown in the text) Figure 2 The AC-DC power stage (208) typically only handles DC power and losses, and generally does not handle AC power used for AC heating. In some examples, AC power is supplied to a high-voltage capacitor C. hv Mid-cycle. Total high-voltage side current i hv,total The capacitor C can be delayed. hv voltage v hv The temperature reaches 90 degrees. Total high-voltage side current i hv,total It can be the individual high-voltage side pile current i hv,post1 to i hv,post4The sum of (e.g., vector addition). As described above, in some embodiments, the outputs generated by each DC-DC converter in a DC-DC converter group (e.g., DC-DC converter 212A) can be synchronously added together in a constructive manner. In some embodiments, the input currents of different DC-DC converter groups (e.g., i hv,post1 and i hv,post3 () can be out of phase to avoid capacitor C hv Overstress.

[0083] Figure 5 yes Figure 4 The phase of the current in the charger's charging station and Figure 4 The charger bus (e.g., V) hvbus A diagram showing the phase of the high voltage on the phase-locked loop (PLL). This diagram illustrates the phase of the voltage staked current (e.g., ...). Figure 2 The current i of the 202A charging pile post1 and Figure 2 The current i of the charging pile 202B post2 (Having the same phase). This diagram corresponds to Figure 4 The DC-DC converter group of the charging pile, which is locked to generate cross-current... Figure 2 The charging piles 202A, 202B, 202C, and 202D have medium-voltage side currents i in the same phase. mv Among them, the medium voltage side current i mv The phase relative to the high voltage v hv Rotated 90 degrees. Total high-voltage side current i hv,total It can be the individual high-voltage side pile current i hv,post1 to i hv,post4 The sum of all. High-voltage capacitor C hv The rated value (e.g., about 150A) can handle the total medium voltage side current I. MV (For example, i) mv,post1 +i mv,post2 +i mv,post3 +i mv,post4 The ripple capability is limited to the maximum ripple current (e.g., 500A).

[0084] Figure 6 According to some embodiments Figure 4 A schematic diagram of a charger component (e.g., a control system 600) for controlling AC ripple across multiple DC-DC voltage converters (e.g., DC-DC converters in DC-DC converter groups 212A, 212B, 212C, and / or 212D). Figure 6As shown, 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 (RMS) values ​​of the corresponding input signals. Proportional controller 606A can adjust the response of control system 600 based on the output of adder 604A (e.g., the difference between two input signals). Proportional controller 606B can adjust the response of control system 600 based on the output of adder 604B (e.g., the difference between two input signals). Comparator 608 can take the minimum value between the outputs of proportional controller 606A and proportional controller 606B. Proportional-integral (PI) controller 610 can eliminate steady-state errors and improve the stability of control system 600. PLL 612 can be used to synchronize the phase locked by control system 600. Control signal generator 614 can process input signals to generate ripple command signals (e.g., I ripple,cmd )

[0086] Figure 6 The control method can correspond to, for example Figure 5 The current of the phase-locked charger piles is shown. This applies to all charger piles 202A to 202D in cabinet 204. Figure 2 The DC-DC converter groups 212A to 212D can be locked in the same phase (e.g., -90 degrees) relative to the high-voltage bus 250 ripple. The high voltage on each DC-DC converter group 212A to 212D (e.g., ) and medium pressure (e.g., Bus ripple controllers can limit (e.g., using) I ripple,cmd The maximum ripple on any port. When multiple piles are connected, if the high-voltage bus ripple exceeds the threshold, the current can be automatically reduced (shared proportionally among the piles). The peak ripple current on the pile can be clamped to the level requested by the vehicle (e.g., electric vehicle 100), and any remaining capacity can be shared among one or more other piles.

[0087] The foregoing disclosure is not intended to limit this disclosure to the precise form disclosed or to any particular field of use. Therefore, it is conceivable that various alternative embodiments and / or modifications (whether expressly described or implied herein) are possible based on this disclosure. Having thus described embodiments of this disclosure, those skilled in the art will recognize that changes in form and detail may be made without departing from the scope of this disclosure. Therefore, this disclosure is limited only by the claims.

[0088] In the foregoing specification, this disclosure has been described with reference to specific embodiments. However, those skilled in the art will understand that the various embodiments disclosed herein can be modified or otherwise implemented in various other ways without departing from the spirit and scope of this disclosure. Therefore, this specification should be considered illustrative and is intended to teach those skilled in the art how to manufacture and use various embodiments of the disclosed display components.

[0089] It should be understood that the forms of disclosure shown and described herein are to be considered 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, all of which will be apparent to those skilled in the art who benefit from the description of this 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, allowing for the presence of items, components, or elements not explicitly described. References to the singular should also be interpreted in relation to the plural. Moreover, the various embodiments disclosed herein should be considered illustrative and explanatory in nature and should in no way be construed as limiting the scope of this disclosure.

[0090] All merged references (e.g., appended, attached, coupled, connected, etc.) are used solely to aid the reader's understanding of this disclosure and do not impose any limitations, particularly on the location, orientation, or use of the systems and / or methods disclosed herein. Therefore, merged references (if any) should be interpreted broadly. Furthermore, such merged references do not necessarily imply a direct connection between two elements. Additionally, all numerical terms (such as, but not limited to, "first," "second," "third," "primary," "secondary," "main," or any other common and / or numerical terms) should also be considered merely as identifiers to aid the reader's understanding of the various elements, embodiments, variations, and / or modifications of this disclosure, and may not impose any limitations, particularly regarding the order or preference of any element, embodiment, variation, and / or modification relative to or exceeding another element, embodiment, variation, and / or modification.

[0091] The illustrative algorithms described in conjunction with 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 illustrative logic blocks and modules described in conjunction with the embodiments disclosed herein can be implemented or executed by a machine, such as a processor device, a digital signal processor (“DSP”), an application-specific integrated circuit (“ASIC”), a field-programmable gate array (“FPGA”) or other programmable logic device, 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 alternatively, it may also be a controller, a microcontroller, or a state machine, a combination thereof, etc. The processor device may include a circuit system 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 may also be implemented as a combination of computing devices, such as 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 described primarily with regard to digital technologies herein, the processor device may also primarily include analog components. For example, some or all of the rendering techniques described herein can be implemented in analog circuit systems or hybrid analog and digital circuit systems. The computing environment can include any type of computer system, including but not limited to microprocessor-based computer systems, mainframe computers, digital signal processors, portable computing devices, device controllers, or computing engines within devices.

[0092] It will also be understood that one or more elements depicted in the accompanying drawings / figures may also be implemented in a more separate or integrated manner, or in some cases even removed or rendered inoperable, which may be useful depending on the specific application.

Claims

1. A system for managing a battery pack of an electric vehicle, the system comprising: A sensor is configured to detect the temperature associated with the battery pack; as well as A controller that communicates with the sensor, the controller being configured to: A request is sent to the charger based on the sensor signal from the sensor; as well as At least a portion of the alternating current associated with the request and received from the charger is provided 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 to increase the temperature associated with the first battery cell.

2. The system of claim 1, wherein the controller is configured to send 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 of claim 1, wherein the request specifies at least one of the amplitude, frequency, or DC offset of the alternating current.

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

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

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

7. The system of claim 1, wherein the controller is configured to monitor the alternating current and send an updated request based on the monitoring of the alternating current.

8. An electric vehicle, comprising: Multiple battery cells, including a first battery cell; as well as The battery management system is configured as follows: Detect the conditions associated with the plurality of battery cells; In response to the detection of the condition, a request is sent to the charger; as well as An alternating current associated with the request and received from the charger is provided to at least the first battery cell, such that the internal resistance of the first battery cell and the alternating current increase the temperature associated with the first battery cell.

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

10. The electric vehicle of claim 8, wherein the request specifies a DC offset of the alternating current, and wherein 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 of claim 10, wherein the battery management system is configured to provide the alternating current to the plurality of battery cells to charge at least one of the plurality of battery cells.

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

13. The electric vehicle of claim 8, wherein the request specifies the amplitude and DC offset of the alternating current, and wherein the battery management system is configured to determine the amplitude and DC offset at least in part based on the conditions.

14. The electric vehicle of claim 8, wherein the battery management system is configured to: The amplitude of the alternating current is monitored to generate a monitoring signal; Based on the monitoring signal, an updated request is generated for adjusting the amplitude of the alternating current; and The updated request is sent to the charger.

15. A method for managing a battery pack, the method comprising: Detect the temperature associated with the battery pack; A request is sent to the charger based on the temperature, the request identifying the AC current waveform; as well as At least a portion of the alternating current associated with the request and received from the charger is provided 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 to increase the temperature associated with the first battery cell.

16. The method of claim 15, further comprising: The amplitude of the alternating current is monitored to generate a monitoring signal; as well as An updated request is generated based on the monitoring signal and sent to the charger for adjusting the amplitude of the AC current.

17. The method of claim 15, further comprising: Determine that the temperature associated with the battery pack meets a threshold. The request is sent in response to determining that the temperature associated with the battery pack meets the threshold.

18. The method of claim 15, further comprising: The amplitude, frequency, and DC offset are determined based on at least one of the following: the battery type of the battery pack, the temperature associated with the battery pack, and the state of charge of the battery pack. The alternating current waveform indicates the amplitude, the frequency, and the DC offset.

19. The method of claim 15, further comprising: The alternating current is provided to power the drive unit, compressor, or power conversion system of the electric vehicle.

20. The method of claim 15, wherein the frequency of the alternating current is between 80 Hz and 500 Hz.

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