A thermal management system for a power battery and an electric vehicle
By introducing a resonant inductor circuit into the pre-charge circuit of the power battery, the resonant frequency when the electric drive and the battery are connected in parallel is reduced. The circuit resonance characteristics are used to achieve rapid self-heating of the battery, which solves the heating noise problem of the power battery and is suitable for various battery types.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GAC AION NEW ENERGY AUTOMOBILE CO LTD
- Filing Date
- 2022-10-18
- Publication Date
- 2026-05-29
AI Technical Summary
In the existing technology, the heating noise problem of power batteries has not been effectively solved, and the resonant frequency cannot be further reduced, remaining within the range of human ear sensitivity, thus the noise problem has not been fundamentally solved.
By connecting a resonant inductor circuit in the battery precharge circuit, the resonant inductor is increased, the resonant frequency when the electric drive and battery are connected in parallel is reduced, and the battery can be rapidly self-heated when the frequency reaches the resonant frequency by utilizing the circuit's resonant characteristics, thereby reducing the noise level of heating.
This reduces the noise level of the power battery heating system, expands the applicability of the thermal management system, and makes it suitable for various types of batteries.
Smart Images
Figure CN115489396B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of power battery technology, and more specifically, to a thermal management system for a power battery and an electric vehicle. Background Technology
[0002] Currently, power batteries are the power sources that provide power to tools, typically used in electric vehicles, electric trains, electric bicycles, and golf carts. In existing technologies, parallel resonant heating of power batteries generally disperses noise across various frequencies for averaging, reducing excessive sound pressure levels in specific frequency bands to some extent. However, limited by the inability to further decrease the resonant frequency, its random frequency conversion range is only between 1300 and 1800 Hz, still within the range where the human ear is most sensitive, thus failing to fundamentally solve the noise problem. Summary of the Invention
[0003] The purpose of this application is to provide a thermal management system for a power battery and an electric vehicle, which can achieve the technical effect of reducing the noise level of the power battery heating.
[0004] In a first aspect, embodiments of this application provide a thermal management system for a power battery, including a battery pre-charge circuit and a resonant inductor circuit;
[0005] The battery precharge circuit includes a battery, an electric drive bus capacitor, an inverter assembly, and a drive motor. The inverter assembly and the drive motor are connected. The two ends of the electric drive bus capacitor are respectively connected to the two ends of the inverter assembly. The battery is connected in parallel with the electric drive bus capacitor.
[0006] The resonant inductor circuit includes a first relay and a resonant inductor, with the first relay, the battery, the resonant inductor, and the electric drive bus capacitor connected in series.
[0007] In the above implementation process, the thermal management system of the power battery sets up a resonant inductor circuit, that is, connects the resonant inductor circuit in the battery pre-charge circuit. By adding a resonant inductor, the resonant frequency when the electric drive and the battery are connected in parallel is reduced. Utilizing the circuit resonance characteristics, when the frequency reaches the resonant frequency, the battery current will reach its maximum, and the battery heats up to the maximum, thereby realizing rapid self-heating of the battery. When the circuit operates at the parallel resonance point, the heating noise is reduced. Thus, the thermal management system of the power battery can achieve the technical effect of reducing the heating noise of the power battery.
[0008] Furthermore, the resonant inductor circuit also includes a second relay, one end of which is connected to the first relay, and the other end of which is connected to the resonant inductor.
[0009] Furthermore, the resonant inductor circuit also includes a resonant resistor, which is connected in series with the second relay.
[0010] In the above implementation process, a resonant resistor and a second relay are added to the resonant inductor circuit, thereby increasing the adjustment options for the resonant frequency and improving the applicability of the power battery's thermal management system.
[0011] Furthermore, the resonant inductor circuit also includes a third relay, one end of which is connected to the second relay, and the other end of which is connected to the resonant resistor.
[0012] In the above implementation process, a third relay is added to the resonant inductor circuit to increase the resonant frequency adjustment option, further improving the applicability of the power battery thermal management system.
[0013] Furthermore, the resonant inductor circuit also includes a third relay, one end of which is connected to the first relay, and the other end of the second relay is connected to the resonant inductor.
[0014] Furthermore, the battery precharge circuit also includes a line inductor, which is connected in series with the battery.
[0015] Furthermore, the battery precharge circuit also includes a line resistor, which is connected in series with the line inductance.
[0016] Furthermore, the value of the electric drive bus capacitor corresponds to the value of the resonant inductor.
[0017] In the above implementation process, when the value of the line inductance corresponds to the value of the electric drive bus capacitance, the resonant frequency is the lowest and the battery current is the highest.
[0018] Furthermore, the inverter assembly is a three-phase inverter.
[0019] Furthermore, the drive motor is a three-phase motor, and the three ports of the three-phase motor are respectively connected to the three ports of the three-phase inverter.
[0020] Secondly, embodiments of this application provide an electric vehicle including a thermal management system for a power battery as described in any of the first aspects.
[0021] Other features and advantages disclosed in this application will be set forth in the following description, or some features and advantages may be inferred from the description or determined without doubt, or may be learned by practicing the above-described technology disclosed in this application.
[0022] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description
[0023] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0024] Figure 1 A circuit diagram of a thermal management system for a power battery provided in an embodiment of this application;
[0025] Figure 2 A circuit diagram of the battery precharge circuit provided in an embodiment of this application;
[0026] Figure 3 A schematic diagram of the equivalent circuit of the battery precharge circuit provided in the embodiments of this application;
[0027] Figure 4 A schematic diagram of the equivalent circuit of the thermal management system of the power battery provided in the embodiments of this application;
[0028] Figure 5 A circuit diagram of another thermal management system for a power battery provided in an embodiment of this application. Detailed Implementation
[0029] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely represents selected embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.
[0030] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.
[0031] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.
[0032] Furthermore, the terms "installation," "setup," "equipped with," "connection," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or a point connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.
[0033] Furthermore, the terms "first," "second," etc., are primarily used to distinguish different devices, elements, or components (which may be the same or different in specific type and construction), and are not intended to indicate or imply the relative importance or quantity of the indicated devices, elements, or components. Unless otherwise stated, "a plurality of" means two or more.
[0034] The purpose of this application is to provide a thermal management system for a power battery and an electric vehicle, which can be applied to the heating management of power batteries. This thermal management system for power batteries, by setting up a resonant inductor circuit, specifically connecting a resonant inductor circuit in the battery pre-charge circuit, reduces the resonant frequency when the electric drive and battery are connected in parallel by adding a resonant inductor. Utilizing the circuit's resonant characteristics, the battery current reaches its maximum when the frequency reaches the resonant frequency, at which point the battery heats up to its maximum, thus achieving rapid self-heating of the battery. The circuit operates at the parallel resonant point, reducing the noise level of heating. Therefore, this thermal management system for power batteries can achieve the technical effect of reducing the noise level of heating power batteries.
[0035] In some implementations, the thermal management system for power batteries provided in this application is not limited to commonly used ternary and lithium iron phosphate batteries, but is also applicable to fuel cells, solid-state batteries, etc., which will not be elaborated here.
[0036] Please see Figure 1 , Figure 1 This is a circuit diagram of a thermal management system for a power battery provided in an embodiment of the present application. The thermal management system for the power battery includes a battery pre-charge circuit and a resonant inductor circuit.
[0037] For example, the battery precharge circuit includes a battery S, an electric drive bus capacitor C, an inverter assembly D, and a drive motor M. The inverter assembly D and the drive motor M are connected. The two ends of the electric drive bus capacitor C are respectively connected to the two ends of the inverter assembly D. The battery S is connected in parallel with the electric drive bus capacitor C.
[0038] For example, the resonant inductor circuit includes a first relay K1 and a resonant inductor L1, with the first relay K1, battery S, resonant inductor L1, and electric drive bus capacitor C connected in series.
[0039] For example, in Figure 1 In the thermal management system of the power battery shown, L1 is the resonant inductor of the resonant inductor circuit; I invt I is the current on the inverter side (inverter module D). batt I is the battery current. Cbus This is the current in capacitor C of the electric drive bus.
[0040] For example, the resonant inductor circuit also includes a second relay K2, one end of which is connected to the first relay K1, and the other end of which is connected to the resonant inductor L1.
[0041] For example, the resonant inductor circuit also includes a resonant resistor R2, which is connected in series with the second relay K2.
[0042] For example, by adding a resonant resistor R2 and a second relay K2 to the resonant inductor circuit, the adjustment options for the resonant frequency in the thermal management system of the power battery are increased, thereby improving the applicability of the thermal management system of the power battery.
[0043] For example, the resonant inductor circuit also includes a third relay K3, one end of which is connected to the second relay K2, and the other end of which is connected to the resonant resistor R2.
[0044] For example, adding a third relay K3 to the resonant inductor circuit increases the adjustment options in the thermal management system of the power battery, thereby further improving the application range of the thermal management system of the power battery.
[0045] For example, the battery precharge circuit also includes a line inductance L2, which is connected in series with the battery S.
[0046] For example, the line inductance L2 is the high-voltage line inductance between the battery S and the drive motor M.
[0047] For example, the battery precharge circuit also includes a line resistor R1, which is connected in series with the line inductance L2.
[0048] In some implementations, the resonant inductor L1 is an external resonant inductor, not part of the vehicle itself;
[0049] The line inductance L2 is the line inductance from the battery to the electric drive, which is the parasitic inductance of the vehicle's high-voltage line.
[0050] The first relay K1 is an external relay used to disconnect the external resonant inductor L1;
[0051] The first relay K2 is the vehicle's built-in pre-charge circuit relay;
[0052] The third relay, K3, is the vehicle's built-in negative relay;
[0053] The line resistance R1 is the internal resistance of the vehicle's battery.
[0054] The resonant resistor R2 is the vehicle's built-in pre-charge resistor.
[0055] For example, please see Figure 2 and Figure 3 , Figure 2 This is a circuit diagram of the battery precharge circuit provided in an embodiment of this application. Figure 3 This is a schematic diagram of the equivalent circuit of the battery precharge circuit provided in the embodiments of this application.
[0056] For example, the inverter component D of an electric vehicle will generate a pulsating alternating current I during operation. invt The electric drive bus capacitor C acts as a smoothing filter, filtering out most of the AC current I. Cbus Afterwards, I with only a small amount of ripple current batt Flow through battery S, such as Figure 2 As shown;
[0057] For example, if the current I on the inverter component D side is... invt If we consider it as an equivalent AC current source, then the battery-driven system can be viewed as a typical parallel resonant circuit, such as... Figure 3 As shown; utilizing the resonant characteristics of this circuit, I invt When the frequency reaches the resonant frequency, I batt The power output of battery S will reach its maximum, at which point the heat generation power of battery S is at its maximum, thus achieving rapid self-heating of the battery. However, due to the small line inductance L2 from battery S to the high voltage of the electric drive (typically 2–5 μH), the resonant frequency falls between 1 kHz and 4 kHz, where the human ear is most sensitive, resulting in serious noise problems.
[0058] Please see Figure 4, Figure 4 This is a schematic diagram of the equivalent circuit of the thermal management system for a power battery provided in an embodiment of this application.
[0059] For example, the value of the electric drive bus capacitor C corresponds to the value of the resonant inductor L1.
[0060] For example, in order to reduce noise, one can start by reducing the resonant frequency. A feasible approach is to increase the electric drive bus capacitance C and the line inductance L2.
[0061] In this application, once the electric drive development is complete, the value of the electric drive bus capacitor C is fixed, and most electric drive component manufacturers do not customize the parameters of the electric drive bus capacitor C. Therefore, considering practicality, this embodiment uses the method of increasing the line inductance L2 to reduce the resonant frequency. Figure 1 The parallel resonant inductor circuit of the battery precharge circuit shown has the following AC equivalent circuit: Figure 4 As shown. According to the principle of the fundamental inequality, when the value of the line inductance L2 (in μH) and the value of the electric drive bus capacitance C (in μF) are equal, the resonant frequency is the lowest and the current I is the lowest. batt maximum.
[0062] In some implementations, the thermal management system for the power battery provided in this application adds an AC component id_AC = Asin(2πft) and a DC component id_DC to the id current command, respectively, so that the electric drive inverter side generates an AC current with controllable amplitude and frequency. The method for determining the id_AC and id_DC parameters is as follows:
[0063] (1) The typical value of the electric drive bus capacitor C is about 600μF, the resonant inductor L1 is 600μH, and the line inductance L1 is usually 2~5μH, which can be ignored. When the frequency f = 265Hz in id_AC=Asin(2πft), the circuit reaches the parallel resonance point, and the battery current I batt The maximum frequency was achieved while avoiding the 1kHz to 4kHz range, which is the most sensitive range for the human ear. This frequency was used as the parameter for the final id_AC frequency f.
[0064] (2) Within the maximum allowable current range for temperature rise of inverter component D and drive motor M, select current I by scanning various combinations of id_AC amplitude A and id_DC. batt The maximum id_AC amplitude A and id_DC are used as the final heating command, as shown in Table 1. When id_AC amplitude A = 420 and id_DC = 700, it is used as the final heating command.
[0065]
[0066] Table 1 Combined scan of id_AC amplitude A and id_DC
[0067] In some implementations, the thermal management system for the power battery provided in this application has the following heating strategy:
[0068] (1) Set the current input command iq = 0 to ensure that the torque output of the drive motor M is zero during the heating process, thereby achieving a stationary state of the vehicle;
[0069] (2) Let id = id_AC;
[0070] (3) When the current I batt When stability is achieved, let id = id_AC + id_DC.
[0071] For example, inverter component D is a three-phase inverter.
[0072] For example, the drive motor M is a three-phase motor, and the three ports of the three-phase motor are respectively connected to the three ports of the three-phase inverter.
[0073] Please see Figure 5 , Figure 5 A circuit diagram of another thermal management system for a power battery provided in an embodiment of this application.
[0074] Optionally, the resonant circuit consisting of the first relay K1 and the resonant inductor L1 can also be connected in parallel with the third relay K3 (the vehicle's own negative relay K3), such as... Figure 5 As shown.
[0075] In some embodiments, this application provides an electric vehicle, including as follows: Figures 1 to 5 The thermal management system of the power battery is shown.
[0076] In some implementation scenarios, the thermal management system of the power battery and the electric vehicle provided in this application have been simulated, and the simulation results are in good agreement with the measured amplitude, with a frequency deviation of only 10%. The comparison between simulation and actual measurement verifies the correctness of the parallel resonance analysis and also proves that the solution has good effect and application potential.
[0077] In all embodiments of this application, "large" and "small" are relative terms, "more" and "less" are relative terms, and "upper" and "lower" are relative terms. The embodiments of this application will not elaborate further on the expression of such relative terms.
[0078] It should be understood that the phrases "in this embodiment," "in this application embodiment," or "as an optional implementation" throughout the specification mean that a specific feature, structure, or characteristic related to an embodiment is included in at least one embodiment of this application. Therefore, the phrases "in this embodiment," "in this application embodiment," or "as an optional implementation" appearing throughout the specification do not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Those skilled in the art should also understand that the embodiments described in the specification are all optional embodiments, and the actions and modules involved are not necessarily essential to this application.
[0079] In the various embodiments of this application, it should be understood that the sequence number of each process does not necessarily imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.
[0080] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of protection of the claims.
Claims
1. A thermal management system for a power battery, characterized in that, This includes the battery pre-charge circuit and the resonant inductor circuit; The battery precharge circuit includes a battery, an electric drive bus capacitor, an inverter assembly, and a drive motor. The inverter assembly and the drive motor are connected. The two ends of the electric drive bus capacitor are respectively connected to the two ends of the inverter assembly. The battery is connected in parallel with the electric drive bus capacitor. The resonant inductor circuit includes a first relay and a resonant inductor, wherein the first relay, the battery, the resonant inductor, and the electric drive bus capacitor are connected in series. The battery precharge circuit also includes a line inductor connected in series with the battery, and a line resistor connected in series with the line inductor; the value of the electric drive bus capacitor corresponds to the value of the resonant inductor.
2. The thermal management system for a power battery according to claim 1, characterized in that, The resonant inductor circuit also includes a second relay, one end of which is connected to the first relay, and the other end of which is connected to the resonant inductor.
3. The thermal management system for a power battery according to claim 2, characterized in that, The resonant inductor circuit also includes a resonant resistor, which is connected in series with the second relay.
4. The thermal management system for a power battery according to claim 3, characterized in that, The resonant inductor circuit also includes a third relay, one end of which is connected to the second relay, and the other end of which is connected to the resonant resistor.
5. The thermal management system for a power battery according to claim 2, characterized in that, The resonant inductor circuit also includes a third relay, one end of which is connected to the first relay, and the other end of which is connected to the resonant inductor.
6. The thermal management system for a power battery according to claim 1, characterized in that, The inverter assembly is a three-phase inverter.
7. The thermal management system for a power battery according to claim 6, characterized in that, The inverter assembly is a three-phase inverter, the drive motor is a three-phase motor, and the three ports of the three-phase motor are respectively connected to the three ports of the three-phase inverter.
8. An electric vehicle, characterized in that, Includes the thermal management system for the power battery as described in any one of claims 1 to 7.