Power battery self-heating system and method based on electric drive inverter reconfiguration

Abstract

Disclosed in the present invention is a power battery self-heating system and method based on electric drive inverter reconfiguration. The system comprises an inverter connected in parallel to two ends of a power battery; the inverter comprises three groups of IGBT bridges connected in parallel; a drive motor comprises three winding inductors, the winding inductors are connected to each other at one end, and the other ends of the winding inductors are respectively connected to intermediate circuits of the three groups of IGBT bridges to form three connecting ends; the positive electrode of the power battery is connected to two branches, one branch is connected to the positive electrode end of the inverter by means of a first relay, the other branch is connected to one end of a capacitor by means of an adjustable resistor and a second relay that are connected in series, and one or two connecting ends are connected to the other end of the capacitor; a controller is used for regulating and controlling the states of the first relay, the second relay, and the adjustable resistor according to a monitored temperature of the power battery, so as to realize switching operation of a drive circuit and a self-heating circuit. The present invention can safely and efficiently realize self-heating of the power battery in a low power consumption mode.

Description

TECHNICAL FIELD

[0001] The invention relates to the technical field of heat management of automobile power batteries, in particular to a power battery self-heating system and method based on electric drive inverter reconfiguration. BACKGROUND

[0002] With the advent of the new energy era, the widespread application of power batteries has become an unstoppable trend. However, in extremely cold environments, the electrical performance of power batteries used in new energy vehicles will be significantly compromised, greatly affecting their lifespan. Rapidly increasing the temperature of power batteries is essential for their rapid and large-scale adoption.

[0003] Currently, most power battery pack systems utilize an external heating system or heating circuit to transfer heat to batteries. For instance, the Chinese patent with application number 201810496455.5 discloses a battery pack heating device and a control method, wherein the power battery heating device is designed to be portable and placed outside a vehicle as a separate product. However, its internal components, including power conversion components, heating interfaces, and heating control modules, are highly complex, leading to increased costs and extremely low versatility. Additionally, the Chinese patent with application number 202111033087.9 discloses a self-heating method and device for vehicle batteries, wherein a self-designed LC resonant unit is connected to a power battery, and a resonant circuit is also independent of an electric drive system. However, this significantly increases the complexity and costs of the entire system and reduces the reliability of the system. Furthermore, the Chinese patent with application number 201810316487.2 discloses a pulse discharge self-heating method and device for lithium-ion batteries, which primarily uses high-frequency pulse discharge control for battery self-heating. However, this method requires the power battery to have sufficient power in extremely cold environments and necessitates a sophisticated high-frequency discharge device, making it unsuitable for low-power applications and rendering the solution less feasible for industrialization and promotion. SUMMARY

[0004] The purpose of the invention is to overcome the shortcomings of the prior art, specifically targeting the application scenarios where power batteries fail to operate normally and suffer from reduced lifespan due to extreme cold. The invention provides a power battery self-heating system and method based on electric drive inverter reconfiguration., aiming to solve the problem of nondestructive heating for power batteries, and enabling rapid temperature elevation of power batteries without affecting their lifespan or compromising safety, thereby achieving the goal of using power batteries in all scenarios.

[0005] In order to achieve the above purpose, the invention adopts the following technical scheme.

[0006] In a first aspect of the invention, a self-heating system for power batteries based on electric drive inverter reconfiguration comprises a power battery, an inverter, a drive motor, and a controller; the inverter comprises three IGBT bridges connected in parallel across the power battery; the drive motor comprises three winding inductors, one end of the winding inductors are interconnected, and the other ends of the winding inductors are respectively connected to middle circuits of the three IGBT bridges, forming three connection terminals; a positive electrode of the power battery is connected to two branches, one of the branches is connected to a positive terminal of the inverter via a first relay, the other branch is connected to one end of a capacitor via an adjustable resistor and a second relay connected in series, and one or two of the connection terminals are connected to the other end of the capacitor; and the controller is configured to adjust the states of the first relay, the second relay, and the adjustable resistor according to a monitored temperature of the power battery, so as to switch between a drive circuit and a self-heating circuit.

[0007] In combination with the first aspect, preferably, a negative terminal of the inverter is connected to a negative terminal of the power battery via a third relay, and the third relay is connected to the controller.

[0008] In combination with the first aspect, preferably, each IGBT bridge comprises two IGBTs; the first IGBT bridge comprises a first IGBT and a fourth IGBT, the second IGBT bridge comprises a second IGBT and a fifth IGBT, and the third IGBT bridge comprises a third IGBT and a sixth IGBT; the three winding inductors of the drive motor are referred to as a first winding inductor, a second winding inductor, and a third winding inductor; the other end of the first winding inductor is connected to the middle circuit of the first IGBT bridge, forming a first connection terminal; the other end of the second winding inductor is connected to the middle circuit of the second IGBT bridge, forming a second connection terminal; and the other end of the third winding inductor is connected to the middle circuit of the third IGBT bridge, forming a third connection terminal.

[0009] In combination with the first aspect, preferably, a circuit at the other end of the capacitor is connected to the first connection terminal.

[0010] In combination with the first aspect, preferably, the other end of the capacitor is connected to two parallel circuits, one of which is connected to the first connection terminal, and the other is connected to the second connection terminal.

[0011] In combination with the first aspect, preferably, when the self-heating circuit is in operation, the first relay is in an open state; current flows from the positive electrode of the power battery, takes the other branch, flows in sequence through the adjustable resistor, the second relay, and the capacitor, proceeds to the first winding inductor via the first connection terminal, and subsequently exits via the second winding inductor and the third winding inductor; and the current exiting from the second winding inductor proceeds through the second connection terminal to the fifth IGBT, and then joins with the current which exits from the third winding inductor and proceeds through the third connection terminal to the sixth IGBT, ultimately converging at the negative electrode of the power battery to form a complete self-heating circuit for the power battery.

[0012] In combination with the first aspect, preferably, when the self-heating circuit is in operation, the first relay is in an open state; current flows from the positive electrode of the power battery, takes the other branch, flows in sequence through the adjustable resistor, the second relay, and the capacitor, proceeds to the first winding inductor and the second winding inductor via the first connection terminal and the second connection terminal respectively, subsequently exits via the third winding inductor, and proceeds through the third connection terminal to the sixth IGBT before flowing back to the negative electrode of the power battery, forming a complete self-heating circuit for the power battery.

[0013] In combination with the first aspect, preferably, when the drive circuit is in operation, the first relay is in a closed state, and the second relay is in an open state.

[0014] In a second aspect, the invention provides a self-heating method for power batteries utilizing the self-heating system for power batteries based on electric drive inverter reconfiguration as described in the first aspect, comprising:

[0015] obtaining an initial temperature of an individual cell of a power battery;

[0016] if the initial temperature is below a temperature required for a drive circuit to operate, disconnecting a first relay and simultaneously closing a second relay to enable the power battery to enter a self-heating charge-discharge cycle mode;

[0017] continuously monitoring a temperature of the individual cell during the self-heating charge-discharge cycle of the power battery;

[0018] determining whether the current temperature of the individual cell reaches a set temperature threshold; and

[0019] if the current temperature reaches the set temperature threshold, disconnecting the second relay to stop heating the power battery.

[0020] In combination with the second aspect, preferably, after continuously monitoring a temperature of the individual cell during the self-heating charge-discharge cycle of the power battery, the method further comprises:

[0021] calculating a current temperature rising rate of the individual cell based on the monitored temperature of the individual cell;

[0022] if the current temperature rising rate reaches a first threshold, adjusting a resistance of an adjustable resistor to reduce a heating power of the power battery to a preset power; and

[0023] if the current temperature rising rate reaches a second threshold, disconnecting the second relay to stop heating the power battery.

[0024] In combination with the second aspect, preferably, in the event of sticking when disconnecting the second relay, a third relay is immediately disconnected to interrupt the selfheating circuit.

[0025] In combination with the second aspect, preferably, before enabling the power battery to enter a self-heating charge-discharge cycle mode, the method further comprises:

[0026] disconnecting the second relay and keeping a vehicle in a parked state; and

[0027] alternately activating a first operating state and a second operating state of the system to align rotor teeth of the drive motor with small teeth of an A-phase stator pole, the first operating state comprising closing the first relay and the third relay, and the second operating state comprising disconnecting the first relay and the third relay.

[0028] Compared with the prior art, the invention has the following beneficial effects.

[0029] 1. The power battery self-heating system and method based on electric drive inverter reconfiguration., as provided by the invention, effectively utilize the energy conversion principles of inductors and capacitors through a series design of inductors and capacitors in the power battery self-heating circuit. The sinusoidal AC current generated from the LC resonant circuit allows for lossless charging and discharging of the power battery, enabling the switchable operation of the drive circuit and the self-heating circuit without affecting the lifespan of the power battery.

[0030] 2. The system of the invention features an adjustable resistor in the power battery selfheating circuit, which protects the circuit while regulating the current flow. This allows for adjustable self-heating power, leading to more effective regulation of the temperature of the power battery.

[0031] 3. The method of the invention addresses the prevention of thermal runaway during the self-heating process of the power battery by employing a two-level warning mechanism. First, it continuously monitors the temperature rising rate of the individual cells. If the current temperature rising rate reaches the first threshold, the resistance of the adjustable resistor is promptly adjusted to reduce the heating power of the power battery to the preset power. Second, if the current temperature rising rate reaches the second threshold, the second relay is immediately disconnected. Additionally, the system comprises a redundant third relay to prevent thermal runaway incidents caused by the sticking of the second relay.

[0032] 4. The method of the invention incorporates a suppression design for the electromagnetic torque generated by the self-heating circuit. In the parked mode, the system alternates between the first operating state and the second operating state, effectively reducing the peak electromagnetic torque and thereby diminishing the noise and vibration produced by the motor during the selfheating process.

[0033] 5. The invention reconfigures the electric drive inverter by connecting one or two connection terminals to the other end of the capacitor, and adopts a “one in, two out” or “two out, one in” current flow design for the star winding inductor of the drive motor. It effectively utilizes the circuit principles of the drive system to achieve energy storage and release of the self-heating system for power batteries without affecting the drive system circuit. By using readily available materials, the development of the self-heating system for power batteries is realized, reducing the heating cost of the power battery system. The invention achieves multiple uses of electrical components in the drive system, and the design of the self-heating system is simple and reliable, avoiding complex modifications to the drive system. This is conducive to rapid product updates and iterations, making it suitable for widespread adoption. BRIEF DESCRIPTION OF DRAWINGS

[0034] Fig. 1 is a structural diagram of a self-heating system for power batteries based on electric drive inverter reconfiguration, which provides a “one in, two out” current flow design for a star winding inductor, according to an embodiment of the invention;

[0035] Fig. 2 is a structural diagram of a self-heating system for power batteries based on electric drive inverter reconfiguration, which provides a “two out, one in” current flow design for a star winding inductor, according to an embodiment of the invention;

[0036] Fig. 3 is a flowchart of a self-heating method for power batteries utilizing a self-heating system for power batteries based on inverter reconfiguration according to an embodiment of the invention; and

[0037] Fig. 4 is a flowchart of a two-level warning mechanism in a self-heating method for power batteries utilizing a self-heating system for power batteries based on inverter reconfiguration according to an embodiment of the invention.

[0038] In the drawings: 1. power battery; 2. adjustable resistor; 3. first relay; 4. second relay; 5. capacitor; 6. inverter; 601. first IGBT; 602. second IGBT; 603. third IGBT; 604. fourth IGBT; 605. fifth IGBT; 606. sixth IGBT; 614. first IGBT bridge; 625. second IGBT bridge; 636. third IGBT bridge; 7. drive motor; 701. first winding inductor; 702. second winding inductor; 703. third winding inductor; 12. controller. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0039] The technical scheme of the invention is described in detail below through the drawings and specific embodiments. It should be understood that the embodiments of the application and the specific features in the embodiments are the detailed description of the technical scheme of the application, rather than a limitation on the technical scheme of the application. Without conflict, the embodiments of the application and the technical features in the embodiments can be combined.

[0040] The term “and / or” herein is only an association relationship describing the associated objects, which means that there can be three kinds of relationships, for example, A and / or B can mean A alone; A and B; and B alone. In addition, the character “ / ” herein generally indicates that the two associated objects are in an “or” relationship.

[0041] As shown in Fig. 1, an embodiment of the invention introduces a self-heating system for power batteries based on electric drive inverter reconfiguration, comprising a power battery 1, an inverter 6, a drive motor 7, and a controller 12; specifically, the inverter 6 comprises three IGBT bridges connected in parallel across the power battery; each IGBT bridge comprises two IGBTs; each IGBT consists of a diode and a switch tube; the first IGBT bridge 614 comprises a first IGBT 604 and a fourth IGBT 604, the second IGBT bridge 625 comprises a second IGBT 602 and a fifth IGBT 605, and the third IGBT bridge 636 comprises a third IGBT 603 and a sixth IGBT 606; the drive motor 7 comprises three winding inductors, and one end of the winding inductors are interconnected in a star shape; the other end of the first winding inductor 701 of the drive motor 7 is connected to a middle circuit of the first IGBT bridge 614, forming a first connection terminal; the other end of the second winding inductor 702 of the drive motor 7 is connected to a middle circuit of the second IGBT bridge 625, forming a second connection terminal; and the other end of the third winding inductor 703 of the drive motor 7 is connected to a middle circuit of the third IGBT bridge 636, forming a third connection terminal.

[0042] Further, a positive electrode of the power battery 1 is connected to two branches, one of the branches is connected to a positive terminal of the inverter 6 via a first relay 3, the other branch is connected to one end of a capacitor 5 via an adjustable resistor 2 and a second relay 4 connected in series, a circuit at the other end of the capacitor 5 is connected to the first connection terminal, and the controller 12 is configured to adjust the states of the first relay 3, the second relay 4, and the adjustable resistor 2 according to a monitored temperature of the power battery 1, so as to switch between a drive circuit and a self-heating circuit.

[0043] As an embodiment of the invention, a negative terminal of the inverter 6 is connected to a negative electrode of the power battery 1 through a third relay 9, and the third relay 9 is connected to the controller 12. This embodiment of the invention provides self-heating circuit protection by setting the third relay 9 to prevent thermal runaway of the power battery 1.

[0044] As an embodiment of the invention, when the drive circuit is in operation, the first relay 3 is in a closed state, and the second relay 4 is in an open state. The drive circuit mainly comprises the power battery 1, the inverter 6, and the drive motor 7. Current flows from the positive electrode of the power battery 1 through the first relay 3 to the inverter 6 and the drive motor 7, and then returns to the negative electrode of the power battery 1 through the third relay 9.

[0045] Specifically, for the self-heating system for power batteries based on electric drive inverter reconfiguration shown in Fig. 1, when the self-heating circuit is in operation, the first relay 3 is in an open state; current flows from the positive electrode of the power battery 1, takes the other branch, flows in sequence through the adjustable resistor 2, the second relay 4, and the capacitor 5, proceeds to the first winding inductor 701 via the first connection terminal, and subsequently exits via the second winding inductor 702 and the third winding inductor 703; and the current exiting from the second winding inductor 702 proceeds through the second connection terminal to the fifth IGBT 605, and then joins with the current which exits from the third winding inductor 703 and proceeds through the third connection terminal to the sixth IGBT 606, ultimately converging at the negative electrode of the power battery 1 to form a complete self-heating circuit for the power battery. It should be noted that the self-heating system for power batteries based on electric drive inverter reconfiguration shown in Fig. 1 employs a short-circuit design for one IGBT bridge, and utilizes switching devices of the other two IGBT bridges to conduct charging and discharging currents for the heating circuit. This approach does not alter the control principle but merely adjusts the control strategy, thereby facilitating the implementation of the self-heating control strategy for the power battery 1. By providing a “one in, two out” current flow design for the star winding inductor of the drive motor 7, the circuit principles of the drive system are effectively utilized to achieve energy storage and release of the self-heating system for power batteries, without affecting the drive system circuit.

[0046] As shown in Fig. 2, an embodiment of the invention presents an alternative self-heating system for power batteries based on electric drive inverter reconfiguration. The structure of the self-heating system for power batteries in Fig. 2 is largely similar to that of the self-heating system for power batteries depicted in Fig. 1. The key difference lies in the connection of the capacitor. In Fig. 1, the other end of the capacitor 5 is connected to the first connection terminal, while in Fig. 2, the other end of the capacitor 5 is connected to two parallel circuits, one of which is connected to the first connection terminal, and the other is connected to the second connection terminal.

[0047] Specifically, for the self-heating system for power batteries based on electric drive inverter reconfiguration shown in Fig. 2, when the self-heating circuit is in operation, the first relay 3 is in an open state; current flows from the positive electrode of the power battery 1, takes the other branch, flows in sequence through the adjustable resistor 2, the second relay 4, and the capacitor 5, proceeds to the first winding inductor 701 and the second winding inductor 702 via the first connection terminal and the second connection terminal respectively, subsequently exits via the third winding inductor 703, and proceeds through the third connection terminal to the sixth IGBT 606 before flowing back to the negative electrode of the power battery 1, forming a complete self-heating circuit for the power battery. Similarly, it should be noted that the self-heating system for power batteries based on electric drive inverter reconfiguration shown in Fig. 2 employs a short-circuit design for two IGBT bridges, and utilizes switching devices of the other IGBT bridge to conduct charging and discharging currents for the heating circuit. This approach does not alter the control principle but merely adjusts the control strategy, thereby facilitating the implementation of the self-heating control strategy for the power battery 1. By providing a “two in, one out” current flow design for the star winding inductor of the drive motor 7, the circuit principles of the drive system are effectively utilized to achieve energy storage and release of the self-heating system for power batteries, without affecting the drive system circuit.

[0048] Furthermore, as an essential component of new energy vehicles, the direct reconfiguration of the electric drive system into the self-heating system for the power battery 1 in this embodiment of the invention is the optimal choice. To prevent system disruption caused by simultaneous operation of both systems, the self-heating system for the power battery 1 will suspend the operation of the drive circuit when the self-heating circuit is active. As illustrated in Fig. 1, the controller 12 is utilized for centralized control of the self-heating process of the power battery 1. Based on the detected temperature of the individual cell of the power battery 1, the controller 12 determines whether to activate the power battery self-heating mode. If it is determined that a signal to heat the power battery is output, the second relay 4 is closed, and simultaneously, the first relay 3 is disconnected, causing the system to enter the self-heating mode. During this mode, the power battery 1 undergoes AC charging and discharging. At this point, the self-heating circuit shorts out the first IGBT bridge 614 via the first connection terminal. When there is no current in the three winding inductors and no voltage in the capacitor 5, the current emitted by the power battery 1 flows through the three winding inductors, the capacitor 5, and other energy storage elements, starting from a small value and increasing gradually, thus forming a self-heating discharge circuit. When the voltage of the capacitor 5 reaches the voltage across the power battery 1, the power battery 1 stops outputting current, while the three winding inductors continue to output current in the same direction, flowing through the power battery 1 to the capacitor 5, until the current decreases to zero. At this point, the voltage of the capacitor 5 will be higher than the voltage across the power battery 1, and the capacitor 5 begins to gradually discharge to the power battery 1. The current in the three winding inductors gradually increases from a small value. When the voltage of the capacitor 5 decreases, the current in the self-heating charging circuit gradually decreases. At this point, the energy stored in the three winding inductors is converted into current to supplement the self-heating circuit until the energy stored in the three winding inductors and the capacitor 5 is completely discharged, thereby forming a complete self-heating charge-discharge cycle circuit for the power battery 1. It should be noted that the current in the discharge circuit flows through the switch tubes of the fifth IGBT 605 and the sixth IGBT 606, while the current in the charging circuit flows through the diodes of the fifth IGBT 605 and the sixth IGBT 606.

[0049] Furthermore, during the self-heating charge-discharge cycle of the power battery 1, the controller 12 simultaneously monitors the temperature and temperature rising rate of the individual cell during the charging and discharging process of the power battery 1. Based on the temperature rising rate, the resistance of the resistor 2 is adjusted to alter the current in the self-heating circuit, thereby adjusting the internal heat generation rate of the power battery 1. This ensures rapid temperature rise while maintaining the safety and lifespan of the power battery 1. Finally, the controller 12 determines whether the temperature of the individual cell of the power battery 1 has reached a set temperature threshold. If the cell temperature reaches the set temperature threshold, the second relay 4 is disconnected to stop the self-heating of the power battery.

[0050] As shown in Fig. 3, an embodiment of the invention further provides a self-heating method for power batteries utilizing the self-heating system for power batteries based on electric drive inverter reconfiguration as illustrated in any one of Fig. 1 or Fig. 2. The method specifically comprises the following steps: [0051 ] SI, obtaining an initial temperature of an individual cell of a power battery 1;

[0052] S2, if the initial temperature is below a temperature required for a drive circuit to operate, disconnecting a first relay 3 and simultaneously closing a second relay 4 to enable the power battery 1 to enter a self-heating charge-discharge cycle mode;

[0053] S3, continuously monitoring a temperature of the individual cell during the self-heating charge-discharge cycle of the power battery 1;

[0054] S4, determining whether the current temperature of the individual cell reaches a set temperature threshold; and

[0055] S5, if the current temperature reaches the set temperature threshold, disconnecting the second relay 4 to stop heating the power battery.

[0056] As an embodiment of the invention, in consideration of the potential risk of thermal runaway during the use of the self-heating system for the power battery 1, the method of the invention adopts a two-level warning mechanism. Specifically, as shown in Fig. 4, after executing S3 provided in this embodiment, the following steps are also included:

[0057] step a: calculating a current temperature rising rate of the individual cell based on the monitored temperature of the individual cell;

[0058] step b: if the current temperature rising rate reaches a first threshold, adjusting a resistance of an adjustable resistor 2 to reduce a heating power of the power battery 1 to a preset power;

[0059] step c: if the current temperature rising rate reaches a second threshold, disconnecting the second relay 4 to stop heating the power battery; and

[0060] step d: in the event of sticking when disconnecting the second relay 4, immediately disconnecting a third relay 9 to interrupt the self-heating circuit.

[0061] Further, it should be noted that during the self-heating process of the power battery 1, the heating current flowing through the winding inductors will cause the drive motor 7 to generate electromagnetic torque. The electromagnetic torque pulsates with changes in the amplitude of the AC excitation, which can easily lead to vibration and noise issues in the drive motor 7. The method provided in this embodiment of the invention utilizes the alternating operation of two states of the drive system before the power battery enters the self-heating charge-discharge cycle to reduce the vibration and noise of the drive motor 7. The specific steps include:

[0062] disconnecting the second relay 4 and keeping a vehicle in a parked state; and

[0063] alternately activating a first operating state and a second operating state of the system to align rotor teeth of the drive motor 7 with small teeth of an A-phase stator pole.

[0064] Here, the first operating state involves closing the first relay 3 and the third relay 9, allowing current to flow through the switch tube of the first IGBT 601, enter the first winding inductor 701, and then exit from the second winding inductor 702 and the third winding inductor 703. The current then enters the fifth IGBT 605 and the sixth IGBT 606 separately, passes through the third relay 9, and finally returns to the power battery 1. The second operating state involves disconnecting the first relay 3 and the third relay 9, allowing the current stored in the three winding inductors to flow in the same direction. The current exits from the fifth IGBT 605 and the sixth IGBT 606, and flows back to the three winding inductors through the diode of the fourth IGBT 604, generating a DC current that passes through the three winding inductors to produce an appropriate torque and reduce the electromagnetic torque peak. This process then proceeds to selfheating, thereby achieving the purpose of reducing motor noise and vibration.

[0065] In summary, the power battery self-heating system and method based on electric drive inverter reconfiguration, provided by the embodiments of the invention design the self-heating system for the power battery 1 by reconfiguring the electric drive inverter in the form of a series connection between the capacitor 5 and the winding inductors of the drive motor 7. The IGBT bridge of the electric drive inverter is short-circuited, and the start-stop control of charging and discharging current in the self-heating circuit for the power battery is performed using other nonshort-circuited IGBT bridges. The adjustable resistor 2 is arranged in the self-heating circuit for the power battery 1 to protect the circuit and adjust the current in the circuit. In addition, considering the prevention of thermal runaway during the self-heating process of the power battery 1, the two-level warning mechanism is adopted to continuously monitor the temperature rising process of the power battery 1, and the third relay 9 at the negative electrode of the power battery 1 is redundantly designed to prevent thermal runaway accidents caused by the sticking of the second relay 4. This can effectively solve the problem of non-destructive heating of the power battery and achieve rapid temperature rise of the power battery 1 without affecting lifespan or compromising safety. It also broadens the applicable scenarios. The scheme of the invention is highly feasible and suitable for industrialization and promotion.

[0066] Those skilled in the art will appreciate that the embodiments of the application may be provided as methods, systems, or computer program products. Therefore, the application may take the form of a full hardware embodiment, a full software embodiment, or an embodiment combining software and hardware aspects. Further, the application may take the form of a computer program product implemented on one or more computer usable storage media (including but not limited to magnetic disk memory, CD-ROM, optical memory, etc.) having computer usable program code embodied therein.

[0067] The application is described with reference to flowcharts and / or block diagrams of the method, device (system), and computer program product according to the embodiments of the application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and combinations of flows and / or blocks in the flowcharts and / or block diagrams, may be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions executed by the processor of the computer or other programmable data processing apparatus produce a device for implementing the functions specified in one or more flows in the flowcharts and / or one or more blocks in the block diagrams.

[0068] These computer program instructions may also be stored in a computer-readable memory which can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including an instruction device which implements the functions specified in one or more flows in the flowcharts and / or one or more blocks in the block diagrams.

[0069] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus such that a series of operational steps are performed on the computer or other programmable apparatus to produce a computer implemented process, such that the instructions executed on the computer or other programmable apparatus provide steps for implementing the functions specified in one or more flows in the flowcharts and / or one or more blocks in the block diagrams.

[0070] The above are only preferred embodiments of the invention, and it should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the invention, several improvements and variations can be made, and these improvements and variations should also be considered within the scope of protection of the invention.

Claims

1. A self-heating system for power batteries based on electric drive inverter reconfiguration, comprising a power battery, an inverter, a drive motor, and a controller; wherein the inverter comprises three IGBT bridges connected in parallel across the power battery; the drive motor comprises three winding inductors, one end of the winding inductors are interconnected, and the other ends of the winding inductors are respectively connected to middle circuits of the three IGBT bridges, forming three connection terminals; a positive electrode of the power battery is connected to two branches, one of the branches is connected to a positive terminal of the inverter via a first relay, the other branch is connected to one end of a capacitor via an adjustable resistor and a second relay connected in series, and one or two of the connection terminals are connected to the other end of the capacitor; and the controller is configured to adjust the states of the first relay, the second relay, and the adjustable resistor according to a monitored temperature of the power battery, so as to switch between a drive circuit and a self-heating circuit.

2. The self-heating system for power batteries based on electric drive inverter reconfiguration according to claim 1, wherein a negative terminal of the inverter is connected to a negative terminal of the power battery via a third relay, and the third relay is connected to the controller.

3. The self-heating system for power batteries based on electric drive inverter reconfiguration according to claim 2, wherein each IGBT bridge comprises two IGBTs; the first IGBT bridge comprises a first IGBT and a fourth IGBT, the second IGBT bridge comprises a second IGBT and a fifth IGBT, and the third IGBT bridge comprises a third IGBT and a sixth IGBT; the three winding inductors of the drive motor are referred to as a first winding inductor, a second winding inductor, and a third winding inductor; the other end of the first winding inductor is connected to the middle circuit of the first IGBT bridge, forming a first connection terminal; the other end of the second winding inductor is connected to the middle circuit of the second IGBT bridge, forming a second connection terminal; and the other end of the third winding inductor is connected to the middle circuit of the third IGBT bridge, forming a third connection terminal.

4. The self-heating system for power batteries based on electric drive inverter reconfiguration according to claim 3, wherein a circuit at the other end of the capacitor is connected to the first connection terminal.

5. The self-heating system for power batteries based on electric drive inverterreconfiguration according to claim 3, wherein the other end of the capacitor is connected to two parallel circuits, one of which is connected to the first connection terminal, and the other is connected to the second connection terminal.

6. The self-heating system for power batteries based on electric drive inverter reconfiguration according to claim 4, wherein when the self-heating circuit is in operation, the first relay is in an open state; current flows from the positive electrode of the power battery, takes the other branch, flows in sequence through the adjustable resistor, the second relay, and the capacitor, proceeds to the first winding inductor via the first connection terminal, and subsequently exits via the second winding inductor and the third winding inductor; and the current exiting from the second winding inductor proceeds through the second connection terminal to the fifth IGBT, and then joins with the current which exits from the third winding inductor and proceeds through the third connection terminal to the sixth IGBT, ultimately converging at the negative electrode of the power battery to form a complete self-heating circuit for the power battery.

7. The self-heating system for power batteries based on electric drive inverter reconfiguration according to claim 5, wherein when the self-heating circuit is in operation, the first relay is in an open state; current flows from the positive electrode of the power battery, takes the other branch, flows in sequence through the adjustable resistor, the second relay, and the capacitor, proceeds to the first winding inductor and the second winding inductor via the first connection terminal and the second connection terminal respectively, subsequently exits via the third winding inductor, and proceeds through the third connection terminal to the sixth IGBT before flowing back to the negative electrode of the power battery, forming a complete self-heating circuit for the power battery.

8. The self-heating system for power batteries based on electric drive inverter reconfiguration according to claim 1, wherein when the drive circuit is in operation, the first relay is in a closed state, and the second relay is in an open state.

9. A self-heating method for power batteries utilizing the self-heating system for power batteries based on electric drive inverter reconfiguration according to any one of claims 1 to 8, comprising:obtaining an initial temperature of an individual cell of a power battery;if the initial temperature is below a temperature required for a drive circuit to operate, disconnecting a first relay and simultaneously closing a second relay to enable the power batteryto enter a self-heating charge-discharge cycle mode;continuously monitoring a temperature of the individual cell during the self-heating chargedischarge cycle of the power battery;determining whether the current temperature of the individual cell reaches a set temperature threshold; andif the current temperature reaches the set temperature threshold, disconnecting the second relay to stop heating the power battery.

10. The method according to claim 9, after continuously monitoring a temperature of the individual cell during the self-heating charge-discharge cycle of the power battery, further comprising:calculating a current temperature rising rate of the individual cell based on the monitored temperature of the individual cell;if the current temperature rising rate reaches a first threshold, adjusting a resistance of an adjustable resistor to reduce a heating power of the power battery to a preset power; andif the current temperature rising rate reaches a second threshold, disconnecting the second relay to stop heating the power battery.

11. The method according to claim 10, wherein in the event of sticking when disconnecting the second relay, a third relay is immediately disconnected to interrupt the self-heating circuit.

12. The method according to claim 9, before enabling the power battery to enter a self-heating charge-discharge cycle mode, further comprising:disconnecting the second relay and keeping a vehicle in a parked state; andalternately activating a first operating state and a second operating state of the system to align rotor teeth of the drive motor with small teeth of an A-phase stator pole, the first operating state comprising closing the first relay and the third relay, and the second operating state comprising disconnecting the first relay and the third relay.

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