Battery heating circuit, battery thermal management system and vehicle

Abstract

The utility model discloses a battery heating circuit, a battery thermal management system and a vehicle, relates to the technical field of power electronics, and realizes rapid and uniform heating of a battery in a low-temperature environment. The battery heating circuit comprises a full-bridge inverter circuit, an LC series circuit and a filter inductor, switch tubes on four bridge arms of the full-bridge inverter circuit are all switch tubes with antiparallel diodes; the input positive electrode of the full-bridge inverter circuit is used for being connected with the positive electrode of a battery. The input negative electrode of the full-bridge inverter circuit is used for being connected with the negative electrode of the battery. Two output terminals of the full-bridge inverter circuit are respectively connected to two ends of the LC series circuit; and the filter inductor is connected in series with a bus capacitor of the battery.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and in particular to a battery heating circuit, a battery thermal management system, and a vehicle. Background Technology

[0002] Ensuring the safe and efficient operation of batteries across the entire temperature range, especially in low-temperature environments, has always been a focus of attention in the field of battery thermal management. In low-temperature environments, the discharge capacity of batteries decreases significantly, and lithium plating at the anode is prone to occur during low-temperature charging, which severely affects battery performance. Therefore, it is necessary to perform heat treatment on batteries operating in low-temperature environments (heat treatment of the battery essentially involves heating the battery cells).

[0003] Traditional battery heating solutions mainly heat the battery by heating the thermal management coolant circuit, but this external heating method has problems such as slow heating speed and uneven heating. Utility Model Content

[0004] In view of the above problems, this application provides a battery heating circuit, a battery thermal management system, and a vehicle to achieve rapid and uniform heating of the battery in low-temperature environments. The specific solution is as follows:

[0005] The first aspect of this application provides a battery heating circuit, including: a full-bridge inverter circuit, an LC series circuit, and a filter inductor;

[0006] The switching transistors on all four arms of the full-bridge inverter circuit are switching transistors with anti-parallel diodes.

[0007] The positive input terminal of the full-bridge inverter circuit is used to connect to the positive terminal of the battery; the negative input terminal of the full-bridge inverter circuit is used to connect to the negative terminal of the battery.

[0008] The two output terminals of the full-bridge inverter circuit are respectively connected to the two ends of the LC series circuit;

[0009] The filter inductor is connected in series with the bus capacitor of the battery.

[0010] In one possible implementation, the switching transistor is an insulated gate bipolar transistor (IGBT) or a metal-oxide-semiconductor field-effect transistor (MOSFET).

[0011] In one possible implementation, the battery heating circuit further includes a temperature sensor for measuring the internal temperature of the battery;

[0012] The output terminal of the temperature sensor is connected to the control electrode of the switching transistor in the same control unit.

[0013] In one possible implementation, the temperature sensor is a negative temperature coefficient (NTC) temperature sensor.

[0014] In one possible implementation, the battery heating circuit is arranged within an electromagnetic shielding layer.

[0015] In one possible implementation, the battery heating circuit further includes an overcurrent protection circuit connected to the positive or negative input terminal of the full-bridge inverter circuit.

[0016] In one possible implementation, the driving circuit for the switching transistor is an isolated driving circuit.

[0017] A second aspect of this application provides a battery thermal management system, including a battery heating circuit as described in the first aspect or any implementation thereof.

[0018] A third aspect of this application provides a vehicle comprising: a battery, and a battery thermal management system as described in the second aspect; the battery being connected to the battery thermal management system.

[0019] In one possible implementation, the battery is a power battery.

[0020] By employing the aforementioned technical solution, this application enables the periodic charging and discharging of a battery based on the synergistic effect of a full-bridge inverter circuit and an LC series circuit. In low-temperature environments, the battery's internal resistance increases, resulting in significant Joule heat generation during periodic charging and discharging. Compared to traditional external heating methods, Joule heat is generated directly within the battery, reducing heat loss during transfer and thus accelerating heating. Simultaneously, the Joule heat dissipates evenly from within the battery, avoiding uneven heat distribution and significantly improving heating uniformity. Furthermore, the output frequency of the full-bridge inverter circuit is adjustable. By matching the output frequency with the inherent resonant frequency of the LC series circuit, the circuit enters a resonant state. In this resonant state, the total circuit impedance is minimized, and the battery charging and discharging current increases substantially, maximizing the Joule heat generated by the battery's internal resistance and thus maximizing the battery heating speed. The filter inductor is used to suppress voltage ripple across the bus capacitor during dynamic switching of the full-bridge inverter circuit's discharge. Attached Figure Description

[0021] The above and other features, advantages, and aspects of the embodiments of this disclosure will become more apparent when taken in conjunction with the accompanying drawings and the following detailed description. Throughout the drawings, the same or similar reference numerals denote the same or similar elements. It should be understood that the drawings are schematic, and the originals and elements are not necessarily drawn to scale.

[0022] Figure 1 This application provides an electrical schematic diagram of a battery heating circuit.

[0023] Figure 2 A schematic diagram of the current flow direction of a battery heating circuit in stage 1 provided in this application;

[0024] Figure 3 A schematic diagram of the current flow direction of a battery heating circuit in stage 2 provided in this application;

[0025] Figure 4 A schematic diagram of the current flow direction of a battery heating circuit in stage 3 provided in this application;

[0026] Figure 5 A schematic diagram of the current flow direction in stage 4 of a battery heating circuit provided in this application. Detailed Implementation

[0027] With the booming development of new energy vehicles and various electronic devices, ensuring the safe and efficient operation of batteries across the entire temperature range, especially in low-temperature environments, has always been a focus of industry attention. Whether it's the power batteries for electric vehicles or the small batteries in various electronic devices, low-temperature environments pose severe challenges to battery performance, mainly in the following two aspects:

[0028] 1) Discharge capacity significantly reduced

[0029] Low temperatures increase electrolyte viscosity and decrease ion diffusion coefficient, leading to a slower lithium-ion transport rate between electrodes. Simultaneously, the activity of electrode materials decreases with lower temperatures, resulting in slower chemical reaction rates and increased battery internal resistance. These factors combined cause a significant reduction in the discharge capacity of the power battery.

[0030] 2) Lithium deposition at the anode

[0031] During low-temperature charging of batteries, the diffusion rate of lithium ions on the negative electrode surface decreases, making it difficult for them to embed into the graphite negative electrode in time. This leads to the precipitation of metallic lithium and the formation of lithium dendrites on the negative electrode surface. The growth of lithium dendrites not only punctures the separator, causing internal short circuits and thermal runaway, but also causes irreversible loss of active lithium, further increasing the battery's internal resistance and resulting in irreversible capacity decay, severely affecting the battery's performance in low-temperature environments.

[0032] Therefore, it is necessary to heat-treat batteries operating in low-temperature environments. This heat treatment essentially involves heating the battery cells.

[0033] Traditional battery heating solutions primarily heat the battery cells by heating the battery's thermal management coolant circuit. However, this external heating method has several problems, mainly in the following two aspects:

[0034] 1) Slow heating speed

[0035] There is thermal resistance during heat transfer. After the coolant absorbs heat, it needs to pass through pipes, battery casing and other components to be transferred to the battery cell. The heat transfer path is long, and there will be some heat loss during this process, and the heat transfer speed is limited.

[0036] 2) Uneven heating

[0037] The flow of coolant in the circuit is prone to unevenness, resulting in significant differences in the degree of heat exchange between the cells and the coolant in different parts of the battery. In addition, the complex structural design of the battery, such as the layout of the internal coolant channels, also affects heat transfer and distribution, making it difficult to ensure heating uniformity.

[0038] To achieve rapid and uniform heating of batteries (including but not limited to power batteries in new energy vehicles) in low-temperature environments, embodiments of this application provide a battery heating circuit, a battery thermal management system, and a vehicle. This battery heating circuit utilizes the characteristic of higher internal resistance in batteries at low temperatures. The charging and discharging process of the battery generates a large amount of Joule heat (Joule heating, also known as the Joule effect or resistance heating, refers to the phenomenon where electrical energy is converted into heat energy when current passes through a conductor due to the resistance within the conductor), thereby achieving rapid and uniform heating of the battery in low-temperature environments and ensuring its safe and efficient operation. This is mainly reflected in the following three aspects:

[0039] 1) In low-temperature environments, the battery's internal resistance increases significantly. According to Joule's law, Q=I 2 As can be seen from Rt, a larger internal resistance R will lead to more Joule heat generation, which allows the heat generated on the internal resistance R through the battery's own charging and discharging process to quickly increase the temperature of the battery cell.

[0040] 2) Joule heating is generated directly inside the battery, which reduces heat loss during the transfer process compared to traditional external heating methods, and further accelerates the battery heating speed.

[0041] 3) Since Joule heating is generated directly inside the battery, the heat is evenly dissipated from inside the cell. Compared with traditional external heating methods, this greatly reduces the heat transfer path and avoids uneven heat distribution caused by long-distance transmission and complex structural interference. It can more accurately heat all parts of the battery cell evenly, significantly improve heating uniformity, and ensure that the temperature of all parts of the battery cell tends to be consistent.

[0042] The following description, in conjunction with the accompanying drawings, describes a battery heating circuit, a battery thermal management system, and a vehicle according to embodiments of this application. Those skilled in the art will recognize that, with technological advancements and the emergence of new scenarios, the technical solutions provided in these embodiments are equally applicable to similar technical problems.

[0043] The terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms are interchangeable where appropriate; this is merely a way of distinguishing objects with the same attributes in the embodiments of this application. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, so that a process, method, system, product, or apparatus that comprises a series of elements is not necessarily limited to those elements, but may include other elements not explicitly listed or inherent to those processes, methods, products, or apparatuses.

[0044] See Figure 1 The battery heating circuit provided in this application includes: a full-bridge inverter circuit 1, an LC series circuit 2, and a filter inductor L1;

[0045] In this circuit, the switching transistors on the four bridge arms of the full-bridge inverter circuit 1 are all switching transistors with anti-parallel diodes.

[0046] The positive input terminal of the full-bridge inverter circuit 1 is used to connect to the positive terminal of battery E, and the negative input terminal of the full-bridge inverter circuit 1 is used to connect to the negative terminal of battery E.

[0047] The two output terminals of the full-bridge inverter circuit 1 are respectively connected to the two ends of the LC series circuit 2;

[0048] One end of the filter inductor L1 is connected in series with the bus capacitor C2 of battery E.

[0049] The following section will detail the structure and function of the full-bridge inverter circuit 1 and the LC series circuit 2, focusing on their collaborative operation in the battery heating circuit. Figure 1 The working principle of the illustrated embodiment:

[0050] 1) Structure and function of full-bridge inverter circuit 1

[0051] The full-bridge inverter circuit 1 is a circuit structure consisting of four switching transistors (in this embodiment, each of the four switching transistors is connected to an anti-parallel diode; "anti-parallel" means that the power input terminal of the switching transistor is connected to the cathode of the diode, and the power output terminal of the switching transistor is connected to the anode of the diode). By precisely controlling the conduction and cutoff of these four switching transistors, it can convert DC input voltage into AC output voltage. These four switching transistors are connected in pairs to form four bridge arms, and the overall layout resembles a quadrilateral "bridge", hence the name "full-bridge inverter circuit".

[0052] For ease of description, these four switching transistors are referred to as the first switching transistor Q1, the second switching transistor Q2, the third switching transistor Q3, and the fourth switching transistor Q4, respectively. The power input terminal of the first switching transistor Q1 is connected to the power input terminal of the second switching transistor Q2, serving as the positive input terminal of the full-bridge inverter circuit 1, used to connect to the positive terminal of battery E. The power output terminal of the third switching transistor Q3 is connected to the power output terminal of the fourth switching transistor Q4, serving as the negative input terminal of the full-bridge inverter circuit 1, used to connect to the negative terminal of battery E. The power output terminal of the first switching transistor Q1 is connected to the power input terminal of the third switching transistor Q3, serving as the first output terminal P1 of the full-bridge inverter circuit 1. The power output terminal of the second switching transistor Q2 is connected to the power input terminal of the fourth switching transistor Q4, serving as the second output terminal P2 of the full-bridge inverter circuit 1. The control electrodes of these four switching transistors are all connected to the control unit, which uses PWM (Pulse Width Modulation) technology. By adjusting the duty cycle, frequency, phase and other parameters of the PWM signal, the control unit can precisely control the conduction and turn-off of these four switching transistors, so that the full-bridge inverter circuit 1 outputs the required AC signal.

[0053] 2) Structure and function of LC series circuit 2

[0054] LC series circuit 2 consists of an inductor L and a capacitor C connected in series. When the frequency of the AC input signal to LC series circuit 2 equals its natural resonant frequency, LC series circuit 2 reaches resonance. The formula for calculating its natural resonant frequency is:

[0055]

[0056] In the above formula, f0 is the natural resonant frequency, L is the inductance value of inductor L, and C is the capacitance value of capacitor C.

[0057] In the resonant state, the inductive reactance of inductor L and the capacitive reactance of capacitor C are equal and cancel each other out. At this time, the total impedance of LC series circuit 2 is the minimum.

[0058] 3) Cooperative operation of full-bridge inverter circuit 1 and LC series circuit 2

[0059] exist Figure 1 In the battery heating circuit shown, the LC series circuit 2 is connected between the first output terminal P1 and the second output terminal P2 of the full-bridge inverter circuit 1. The control unit sends a PWM signal to control the on and off of the four switching transistors in the full-bridge inverter circuit 1 in a specific sequence. One PWM control cycle is divided into the following four stages, which are unfolded in chronological order:

[0060] Phase 1:

[0061] In stage 1, the first switch Q1 and the fourth switch Q4 are turned on, while the second switch Q2 and the third switch Q3 are kept off. (See below for further details.) Figure 2 The diagram shows the current flow: When battery E discharges, the current flows out from the positive terminal of battery E, passes through the first switch Q1, the LC series circuit 2, and the fourth switch Q4 in sequence, and then flows back to the negative terminal of battery E, forming a battery discharge circuit.

[0062] Phase 2:

[0063] In stage 2, all four control switches are turned off, and the LC series circuit 2, which is in an energy storage state, begins to discharge. Due to the current-maintaining characteristic of inductor L and the discharging effect of capacitor C, the current direction in the circuit reverses. See [link to relevant documentation]. Figure 3 The current flow diagram shown is as follows: The current flows out from the first end of the LC series circuit 2 (which is the same node as the first output terminal P1), passes through the anti-parallel diode of the first switch Q1, the battery E, and the anti-parallel diode of the fourth switch Q4 in sequence, and then flows back to the second end of the LC series circuit 2 (which is the same node as the second output terminal P2), forming a battery charging circuit.

[0064] Phase 3:

[0065] In stage 3, the second switch Q2 and the third switch Q3 are turned on, while the first switch Q1 and the fourth switch Q4 remain off. (See below for further details.) Figure 4 The diagram shows the current flow: When battery E discharges, the current flows out from the positive terminal of battery E, passes through the second switch Q2, the LC series circuit 2, and the third switch Q3 in sequence, and then flows back to the negative terminal of battery E, forming a battery discharge circuit.

[0066] Phase 4:

[0067] In stage 4, all four control switches are turned off, and the LC series circuit 2, which is in an energy storage state, begins to discharge. Due to the current-maintaining characteristic of inductor L and the discharging effect of capacitor C, the current direction in the circuit reverses. See [link to relevant documentation]. Figure 5 The current flow diagram shown is as follows: The current flows out from the second end of the LC series circuit 2, passes through the anti-parallel diode of the second switch Q2, the battery E, and the anti-parallel diode of the third switch Q3 in sequence, and then flows back to the first end of the LC series circuit 2, forming a battery charging circuit.

[0068] This cycle repeats continuously, resulting in an AC output voltage at the output of the full-bridge inverter circuit 1, thereby enabling the periodic charging and discharging of battery E.

[0069] During the cyclic charging and discharging of battery E, the current acts on the internal resistance of battery E in pulse form, generating Joule heat. Because the internal resistance of battery E is relatively high at low temperatures, a large amount of heat (Joule heat) is generated during the cyclic charging and discharging process. This heat can quickly and evenly heat the battery cell E. Furthermore, the control unit can adjust the frequency of the AC signal output from the full-bridge inverter circuit 1 to match the inherent resonant frequency of the LC series circuit 2 by setting the frequency of the PWM signal, ensuring that the LC series circuit 2 operates in a resonant state. Since the total impedance of the LC series circuit 2 is at its minimum when it reaches resonance, the battery charging and discharging current increases significantly at this time, maximizing the heat generated on the internal resistance of battery E at low temperatures, thus maximizing the heating speed of battery E.

[0070] It should be noted that the battery main circuit can operate normally during the heating process of battery E, as described above. Figure 1 The specific details are as follows: Battery E outputs a DC voltage, which is filtered by the bus capacitor C2 to smooth voltage fluctuations and provide a more stable power supply to the downstream load. A main positive relay K1 is connected between the positive terminal of battery E and one end of the bus capacitor C2, and a main negative relay K2 is connected between the negative terminal of battery E and the other end of the bus capacitor C2. These two relays are used to control the on / off state of the battery's main circuit. When the main positive relay K1 and the main negative relay K2 are closed, a circuit is formed between battery E and the downstream load, and battery E can supply power to the load.

[0071] During the dynamic switching discharge process of the full-bridge inverter circuit 1 (i.e., switching from stage 4 to stage 1, and from stage 2 to stage 3), given that the bus capacitor C2 has low internal resistance and fast response speed, while the battery E has high internal resistance and relatively slow response, the LC series circuit 2 will exhibit instantaneous discharge of the bus capacitor C2, thereby generating a transient large current. Figure 1 In this situation, the filter inductor L1 generates an induced electromotive force based on the principle of electromagnetic induction, thereby suppressing sudden changes in current. Through this mechanism, the filter inductor L1 can effectively reduce the charging and discharging current of the bus capacitor C2, thereby reducing the voltage ripple across the bus capacitor C2 and improving the stability and reliability of the circuit operation. The inductance value of the filter inductor L1 is mainly determined based on the allowable voltage ripple across the bus capacitor C2 during the operation of the full-bridge inverter circuit 1.

[0072] The main positive relay K1 is usually also connected in parallel with a battery pre-charge circuit, see [link to relevant documentation] Figure 1The battery pre-charging circuit includes a pre-charging relay K3 and a pre-charging resistor R1 connected in series. During system startup, since the initial voltage of the bus capacitor C2 is zero, directly closing the main positive relay K1 and the main negative relay K2 would generate a large inrush current, potentially damaging the relays and other circuit components. Therefore, the pre-charging relay K3 is closed first, allowing the battery E to slowly charge the bus capacitor C2 through the pre-charging resistor R1. As the voltage across capacitor C2 gradually increases, the inrush current decreases significantly. When the voltage across the bus capacitor C2 approaches the battery voltage, the main positive relay K1 and the main negative relay K2 are then closed, while the pre-charging relay K3 is opened, thus completing the pre-charging process and ensuring the safe and stable operation of the battery main circuit.

[0073] In summary, this embodiment of the application, based on the synergistic effect of the full-bridge inverter circuit 1 and the LC series circuit 2, enables the battery E to undergo periodic charging and discharging. In low-temperature environments, the internal resistance of battery E increases, causing a significant amount of Joule heat to be generated during the periodic charging and discharging process. Compared to traditional external heating methods, Joule heat is generated directly inside battery E, reducing heat loss during transfer and thus accelerating the heating speed of battery E. Simultaneously, the Joule heat dissipates evenly from within the battery cell, avoiding uneven heat distribution and significantly improving the uniformity of battery E heating. Furthermore, the output frequency of the full-bridge inverter circuit 1 is adjustable. By matching the frequency of the AC signal output by the full-bridge inverter circuit 1 with the inherent resonant frequency of the LC series circuit 2, the LC series circuit 2 can enter a resonant state. In this resonant state, the total circuit impedance is minimized, and the charging and discharging current of battery E increases significantly, maximizing the heat generated by the internal resistance of battery E and thus maximizing the heating speed of battery E. The filter inductor L1 is used to suppress the voltage ripple across the bus capacitor C2 during dynamic switching of the full-bridge inverter circuit 1's discharge.

[0074] In one possible implementation, the switching transistors in the full-bridge inverter circuit 1 are either IGBTs (Insulated Gate Bipolar Transistors) or MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors), and there is no limitation thereto.

[0075] When the switching transistor is an IGBT, the power input terminal is the collector of the IGBT, the power output terminal is the emitter of the IGBT, and the control terminal is the gate of the IGBT. When the switching transistor is a MOSFET, the power input terminal is the drain of the MOSFET, the power output terminal is the source of the MOSFET, and the control terminal is the gate of the MOSFET.

[0076] In one possible implementation, the battery heating circuit provided in any of the above embodiments further includes a temperature sensor for measuring the internal temperature of the battery E. The output of the temperature sensor is connected to the aforementioned control unit, serving as the basis for the control unit to set the duty cycle of the PWM signal. By adjusting the duty cycle, the output power of the full-bridge inverter circuit 1 can be flexibly and accurately controlled.

[0077] Specifically, when the temperature sensor detects that the internal temperature of battery E is significantly lower than the set temperature range, the control unit increases the duty cycle of the PWM signal based on the received temperature signal. An increased duty cycle means that the full-bridge inverter circuit 1 is on for a longer period within one cycle, increasing the average output power. Consequently, the charging and discharging current of battery E also increases accordingly, significantly increasing the heat generated by the internal resistance of battery E, thus accelerating the temperature rise of battery E and allowing it to reach the set temperature range as quickly as possible. Conversely, when the temperature sensor indicates that the internal temperature of battery E is close to or has reached the suitable operating temperature, the control unit decreases the duty cycle of the PWM signal. At this time, the average output power of the full-bridge inverter circuit 1 decreases, the charging and discharging current of battery E decreases, and the generated heat also decreases, preventing battery E from overheating and affecting its performance and lifespan.

[0078] In one possible implementation, the temperature sensor could be an NTC (Negative Temperature Coefficient) temperature sensor. An NTC temperature sensor uses an NTC thermistor as the temperature-sensing element. The characteristic of an NTC thermistor is that its resistance changes with temperature, exhibiting a negative temperature coefficient; that is, the resistance of the NTC thermistor decreases as the temperature increases and increases as the temperature decreases. By accurately measuring the resistance of the NTC thermistor, the internal temperature of the battery can be accurately determined.

[0079] The NTC temperature sensor has a simple structure and no complex mechanical parts, thus possessing high reliability and stability. During long-term battery use, it can withstand various harsh environments, such as high temperature, humidity, and vibration, ensuring the accuracy and stability of temperature measurement and providing strong support for the reliable operation of the battery heating circuit.

[0080] The advantages of NTC temperature sensors are particularly evident when this battery heating circuit is used in automotive power batteries. The driving environment for automobiles is complex, with extreme temperatures, humid rainy seasons, and severe vibrations from bumpy roads being commonplace. Thanks to its simple structure, the NTC temperature sensor can withstand these harsh conditions and reliably sense the power battery temperature. Its accurate measurements help the battery heating circuit to adjust in real time, preventing battery performance damage due to overheating or overcooling. This ensures that the power battery operates efficiently and stably in various environments, providing a solid guarantee for driving safety and range.

[0081] In one possible implementation, the battery heating circuit provided in any of the above embodiments is arranged within an electromagnetic shielding layer.

[0082] Specifically, when the battery heating circuit is operating, components such as the full-bridge inverter circuit generate electromagnetic signals of a certain intensity. These signals may cause electromagnetic interference to surrounding electronic equipment, affecting the normal operation of other devices. Simultaneously, various electromagnetic interference sources exist in the external environment, such as radio signals and electromagnetic radiation from other electrical equipment, which may interfere with the normal operation of the battery heating circuit. Placing the circuit within an electromagnetic shielding layer effectively prevents the leakage of internal electromagnetic signals and the entry of external electromagnetic interference, ensuring the stable operation of the battery heating circuit and surrounding electronic equipment.

[0083] Electromagnetic shielding is particularly important when this battery heating circuit is used in automotive power batteries. A car contains numerous electronic devices, from onboard computers and navigation systems to various sensors, all of which are closely interdependent and highly susceptible to interference. If the electromagnetic signals generated by the battery heating circuit are not shielded, they can easily disrupt the signals of onboard electronic devices, leading to navigation and positioning errors, sensor data distortion, and other problems. Furthermore, complex external electromagnetic environments, such as base station signals and radiation from other vehicle electronic devices, can also interfere with the battery heating circuit. Placing the heating circuit within an electromagnetic shielding layer effectively creates a stable electromagnetic environment, ensuring the stable operation of all automotive systems and improving driving safety and reliability.

[0084] In one possible implementation, the battery heating circuit provided in any of the above embodiments further includes an overcurrent protection circuit connected to the positive or negative input terminal of the full-bridge inverter circuit.

[0085] Specifically, when an overcurrent occurs in the battery heating circuit, the overcurrent protection circuit can promptly cut off the power supply, protecting the battery heating circuit and battery from damage and improving safety. This is especially crucial when the battery heating circuit is used in a vehicle's power battery, where its role is critical to driving safety. Vehicle operating conditions are complex, and sudden surges in current are inevitable. If the battery heating circuit experiences an overcurrent, it could cause overheating and fire, endangering the lives of passengers. In this situation, the overcurrent protection circuit connected to the input of the full-bridge inverter circuit can respond rapidly, cutting off the power supply within milliseconds, preventing abnormal current increases, avoiding burnout of battery heating circuit components and damage to the power battery, thus building a strong safety barrier for the vehicle's power battery system and ensuring safe and stable vehicle operation under various complex conditions.

[0086] In one possible implementation, in the battery heating circuit provided in any of the above embodiments, the driving circuit of the switching transistor adopts an isolated driving circuit. The power section of the battery heating circuit has high voltage and current; the isolated drive can prevent high voltage from entering the control unit, avoiding harm to the control unit and personnel. Furthermore, the switching transistor generates electromagnetic interference when it is turned on and off; the isolated drive can isolate this interference, ensuring accurate and stable control signals, allowing the switching transistor to switch as expected, thereby ensuring the stable and reliable operation of the battery heating circuit.

[0087] This application also provides a battery thermal management system, including the battery heating circuit provided in any of the above embodiments. The battery thermal management system aims to precisely manage and regulate battery temperature. It has multiple functions, not only heating the battery at low temperatures but also possessing powerful cooling capabilities. When the battery is in a high-temperature environment or when the charging / discharging temperature is too high, the cooling function is immediately activated. Cooling methods can include water cooling or air cooling. Simultaneously, by acquiring data in real time using a precision temperature sensor, the battery thermal management system can intelligently and flexibly switch between heating and cooling modes based on preset thresholds, comprehensively ensuring that the battery is always within its optimal operating temperature range, thereby improving battery performance and lifespan.

[0088] This application also provides a vehicle, including: a battery, and a battery thermal management system provided in any of the above embodiments; the battery is connected to the battery thermal management system. This significantly improves the overall performance and reliability of the vehicle, providing users with a safer, more efficient, and longer-lasting travel experience.

[0089] The vehicles described are new energy vehicles. In terms of power source type, these new energy vehicles can be either pure electric vehicles or hybrid electric vehicles. Pure electric vehicles are those equipped only with an electric power source (battery and drive motor) and do not rely on traditional thermal power sources (such as engines). Hybrid electric vehicles are those equipped with both power sources—a thermal power source (traditional engine) and an electric power source (battery and drive motor).

[0090] In one possible implementation, the battery is a power battery. Therefore, when in a low-temperature environment, the battery heating circuit in the battery thermal management system quickly activates, rapidly adjusting the battery temperature to a suitable range. This effectively solves the problems of difficult starting and significantly reduced driving range in traditional vehicles at low temperatures, greatly improving the practicality and reliability of the vehicle in low-temperature environments.

[0091] Of course, this battery can also be any battery in the car other than the main battery, such as an auxiliary battery. With the development of automotive intelligence, there are increasingly more in-vehicle electronic devices, such as intelligent driving assistance systems, vehicle networking devices, in-vehicle entertainment screens, automatic parking sensors, and in-vehicle environmental control systems. These devices all rely on auxiliary batteries for power. Auxiliary batteries are constantly in a charge-discharge cycle and are quite sensitive to temperature. A battery thermal management system can precisely regulate the temperature of the auxiliary battery, preventing performance degradation due to overheating or overcooling, extending its lifespan, ensuring the stable operation of various in-vehicle electronic devices, providing users with a smooth and intelligent driving experience, and further highlighting the practicality and reliability of the vehicle in different scenarios.

[0092] In this specification, the various embodiments focus on explaining the differences from other embodiments, and the same or similar content can be referred to each other. Regarding the battery thermal management system and vehicle disclosed in the embodiments, the description is relatively concise because it covers the battery heating circuit described in the embodiments. For a deeper understanding of how the battery thermal management system uses the battery heating circuit to precisely regulate battery temperature, and the actual operating conditions of a vehicle equipped with this system, the working principles and connection methods of components related to the battery heating circuit, such as the full-bridge inverter circuit and the LC series circuit, can be found in the detailed description of the battery heating circuit section.

[0093] The above description of the disclosed embodiments enables those skilled in the art to make or use this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the embodiments of this application. Therefore, the embodiments of this application are not to be limited to the embodiments shown herein, but are to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A battery heating circuit, characterized by, The battery heating circuit comprises: a full-bridge inverter circuit, an LC series circuit and a filter inductor; all the switching tubes on the four bridge arms of the full-bridge inverter circuit are switching tubes with anti-parallel diodes; the input positive pole of the full-bridge inverter circuit is used for connecting to the positive pole of a battery; the input negative pole of the full-bridge inverter circuit is used for connecting to the negative pole of the battery; the two output terminals of the full-bridge inverter circuit are connected to the two ends of the LC series circuit respectively; the filter inductor is connected in series with a bus capacitor of the battery.

2. The battery heating circuit of claim 1, wherein, The switching tube is an insulated gate bipolar transistor (IGBT) or a metal oxide semiconductor field effect transistor (MOSFET).

3. The battery heating circuit of claim 1, wherein, The battery heating circuit further comprises a temperature sensor for measuring the internal temperature of the battery. The output terminal of the temperature sensor is connected to the control terminal of the switching tube and connected to the same control unit.

4. The battery heating circuit of claim 3, wherein, The temperature sensor is a negative temperature coefficient (NTC) temperature sensor.

5. The battery heating circuit of claim 1, wherein, The battery heating circuit is arranged in an electromagnetic shielding layer.

6. The battery heating circuit of claim 1, wherein, The battery heating circuit further comprises an overcurrent protection circuit connected to the input positive pole or the input negative pole of the full-bridge inverter circuit.

7. The battery heating circuit of any one of claims 1 to 6, wherein, The driving circuit of the switching tube is an isolated driving circuit.

8. A battery thermal management system, characterized by, The battery heating circuit comprises: The battery heating circuit according to any one of claims 1 to 7.

9. A vehicle characterized by comprising: The battery heating circuit comprises: a battery and a battery thermal management system according to claim 8; the battery is connected to the battery thermal management system.

10. The vehicle of claim 9, wherein, The battery is a power battery.

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