Charging and discharging machine circuit, charging and discharging machine and vehicle

Abstract

The invention provides a charging and discharging machine circuit, a charging and discharging machine and a vehicle, the charging and discharging machine circuit comprises an input circuit, an output circuit, a bridge-free PFC (Power Factor Correction) circuit and an output circuit, two ends of the first capacitor are respectively connected with a first output end and a second output end of the bridgeless PFC circuit; the first output end of the bridgeless PFC circuit is further connected with the first input end of the DBSRC circuit, and the second output end of the bridgeless PFC circuit is further connected with the second input end of the DBSRC circuit. The two ends of the fourth capacitor are connected with the first output end and the second output end of the DBSRC circuit respectively. The first output end of the DBSRC circuit is further connected with the first input end of the high-voltage output circuit, and the second output end of the DBSRC circuit is further connected with the second input end of the high-voltage output circuit. The output end of the high-voltage output circuit is connected with a power battery pack; the bridgeless PFC circuit and the DBSRC circuit are further electrically connected with the controller, the controller is used for controlling the DBSRC circuit to repeatedly charge and discharge the power battery pack so as to heat the internal resistance of the power battery pack, the heating cost of the power battery can be reduced, and the service life of the battery can be prolonged.

Description

Technical Field

[0001] This invention relates to the field of low-temperature heating technology for power batteries, and more particularly to a charge / discharger circuit, a charge / discharger, and a vehicle. Background Technology

[0002] At low temperatures, the internal resistance of the power battery pack (also referred to as "battery pack" in this article) increases, leading to a significant decrease in its charge and discharge performance. In extremely low-temperature conditions during winter, the power battery pack needs to be heated to above approximately 0°C to improve its charge and discharge capabilities. Currently, the industry commonly uses heating components, such as heating films or liquid cooling plates, installed on the surface of the modules inside the power battery pack to heat the battery externally. However, this method has significant drawbacks: 1. Installing heating components on the surface of the modules inside the power battery pack requires additional component costs; 2. A module is usually a cuboid, and heating is typically carried out on only one or two of the six sides of the module. This uneven heat conduction can lead to poor battery consistency over time, resulting in a rapid decline in the health of the power battery.

[0003] Therefore, heating the power battery is costly and reduces battery life. Summary of the Invention

[0004] In view of this, embodiments of the present invention provide a charge / discharger circuit, a charge / discharger, and a vehicle, which heats the power battery by heating the internal resistance of the power battery pack, thereby reducing the heating cost of the power battery and improving battery life.

[0005] In a first aspect, embodiments of the present invention provide a charge / discharger circuit, comprising: Input circuit, bridgeless PFC (Power Factor Correction) circuit, first capacitor, DBSRC (Dual Bridge Series Resonant Converter) circuit, fourth capacitor, high voltage output circuit and controller; The input terminal of the input circuit is used for electrical connection with an AC power source; The output terminal of the input circuit is electrically connected to the bridgeless PFC circuit. The two ends of the first capacitor are electrically connected to the first output terminal and the second output terminal of the bridgeless PFC circuit, respectively. The first output terminal of the bridgeless PFC circuit is also electrically connected to the first input terminal of the DBSRC circuit, and the second output terminal of the bridgeless PFC circuit is also electrically connected to the second input terminal of the DBSRC circuit. The two ends of the fourth capacitor are electrically connected to the first output terminal and the second output terminal of the DBSRC circuit, respectively. The first output terminal of the DBSRC circuit is also electrically connected to the first input terminal of the high voltage output circuit, and the second output terminal of the DBSRC circuit is also electrically connected to the second input terminal of the high voltage output circuit. The output terminal of the high-voltage output circuit is used to connect to the power battery pack. The bridgeless PFC circuit and the DBSRC circuit are also electrically connected to the controller, which is used to control the DBSRC circuit to repeatedly charge and discharge the power battery pack in order to heat the internal resistance of the power battery pack.

[0006] Optionally, the bridgeless PFC circuit includes: a first switching transistor, a second switching transistor, a third switching transistor, and a fourth switching transistor; The gates of the first switch, the second switch, the third switch, and the fourth switch are all electrically connected to the controller; The source of the first switching transistor and the drain of the second switching transistor are electrically connected, and the source of the third switching transistor and the drain of the fourth switching transistor are electrically connected. The drain of the first switch and the drain of the third switch are the first output terminals of the bridgeless PFC circuit, and the source of the second switch and the source of the fourth switch are the second output terminals of the bridgeless PFC circuit.

[0007] Optionally, the input circuit includes: a first filter circuit, a pre-charge circuit, a first diode, a second diode, and a first inductor; The input terminal of the first filter circuit is used to be electrically connected to the AC power supply; The first output terminal of the first filter circuit is electrically connected to the input terminal of the pre-charging circuit. The output terminal of the pre-charging circuit is electrically connected to the anode of the first diode, the cathode of the second diode, and one end of the first inductor. The cathode of the first diode is electrically connected to the first output terminal of the bridgeless PFC circuit; The anode of the second diode is electrically connected to the second output terminal of the PFC circuit; The other end of the first inductor is electrically connected to the source of the first switching transistor and the drain of the second switching transistor; The second output terminal of the first filter circuit is electrically connected to the source of the third switch and the drain of the fourth switch.

[0008] Optionally, the DBSRC circuit includes: a fifth switch, a sixth switch, a seventh switch, an eighth switch, a ninth switch, a tenth switch, an eleventh switch, a twelfth switch, a second capacitor, a first transformer, a second inductor, and a third capacitor; The gates of the fifth, sixth, seventh, eighth, ninth, tenth, eleventh, and twelfth switching transistors are all electrically connected to the controller. The source of the fifth switch is electrically connected to the drain of the sixth switch, the source of the seventh switch is electrically connected to the drain of the eighth switch, the source of the ninth switch is electrically connected to the drain of the tenth switch, and the source of the eleventh switch is electrically connected to the drain of the twelfth switch. The drain of the fifth switch and the drain of the seventh switch are the first input terminals of the DBSRC circuit, and the source of the sixth switch and the source of the eighth switch are the second input terminals of the DBSRC circuit. The drain of the ninth switch and the drain of the eleventh switch are the first output terminals of the DBSRC circuit, and the source of the tenth switch and the source of the twelfth switch are the second output terminals of the DBSRC circuit. The source of the fifth switch and the drain of the sixth switch are also electrically connected to one end of the second capacitor, and the other end of the second capacitor is electrically connected to the first end of the primary terminal of the first transformer. The source of the seventh switch and the drain of the eighth switch are also electrically connected to one end of the second inductor, and the other end of the second inductor is electrically connected to the second end of the primary terminal of the first transformer. The source of the ninth switch and the drain of the tenth switch are also electrically connected to one end of the third capacitor, and the other end of the third capacitor is electrically connected to the first end of the secondary winding of the first transformer. The source of the eleventh switch and the drain of the twelfth switch are also electrically connected to the second terminal of the secondary winding of the first transformer.

[0009] Optionally, the charge / discharge circuit further includes: a voltage sensor, electrically connected to the first capacitor and the controller; the voltage sensor is used to detect the voltage across the first capacitor and send the voltage across the first capacitor to the controller.

[0010] Optionally, the controller is specifically used for: The power battery pack is controlled to discharge by turning on the fifth, eighth, ninth, and twelfth switches. When the voltage across the first capacitor is detected to be greater than a set threshold, the power battery pack is charged by controlling the fifth, sixth, seventh, eighth, ninth, tenth, eleventh, and twelfth switching transistors.

[0011] Optionally, the high-voltage output circuit includes: a second filter circuit and a seventh capacitor; The first input terminal of the second filter circuit is the first input terminal of the high voltage output circuit, and the second input terminal of the second filter circuit is the second input terminal of the high voltage output circuit. The first output terminal of the second filter circuit is electrically connected to one end of the first capacitor and is also used to electrically connect to the positive terminal of the power battery pack; the second output terminal of the second filter circuit is electrically connected to the other end of the first capacitor and is also used to electrically connect to the negative terminal of the power battery pack.

[0012] Optionally, the charge / discharger circuit further includes: a fifth capacitor, a hard-switched full-bridge circuit, a sixth capacitor, a second transformer, a seventeenth switching transistor, an eighteenth switching transistor, and a low-voltage output circuit; The first output terminal of the DBSRC circuit is also electrically connected to one end of the fifth capacitor and the first input terminal of the hard-switching full-bridge circuit; the second output terminal of the DBSRC circuit is also electrically connected to the other end of the fifth capacitor and the second input terminal of the hard-switching full-bridge circuit. The first output terminal of the hard-switching full-bridge circuit is electrically connected to one end of the sixth capacitor, and the other end of the sixth capacitor is electrically connected to the first terminal of the primary winding of the second transformer; the second output terminal of the hard-switching full-bridge circuit is electrically connected to the second terminal of the primary winding of the second transformer. The first terminal of the secondary winding of the second transformer is electrically connected to the drain of the seventeenth switching transistor; the second terminal of the secondary winding of the second transformer is electrically connected to the drain of the eighteenth switching transistor. The third terminal of the secondary winding of the second transformer is electrically connected to the first input terminal of the low-voltage output circuit; the source terminals of the seventeenth and eighteenth switching transistors are electrically connected to the second input terminal of the low-voltage output circuit. The gates of the seventeenth and eighteenth switching transistors are electrically connected to the controller.

[0013] Optionally, the hard-switching full-bridge circuit includes: a thirteenth switch, a fourteenth switch, a fifteenth switch, and a sixteenth switch; The gates of the thirteenth, fourteenth, fifteenth, and sixteenth switching transistors are all electrically connected to the controller. The source of the thirteenth switch and the drain of the fourteenth switch are electrically connected, and the source of the fifteenth switch and the drain of the sixteenth switch are electrically connected. The drain of the thirteenth switch and the drain of the fifteenth switch are the first input terminals of the hard-switching full-bridge circuit, and the source of the fourteenth switch and the source of the sixteenth switch are the second input terminals of the hard-switching full-bridge circuit. The source of the thirteenth switch and the drain of the fourteenth switch are electrically connected to the sixth capacitor. The source of the fifteenth switch and the drain of the sixteenth switch are electrically connected to the second terminal of the primary terminal of the second transformer.

[0014] Optionally, the low-voltage output circuit includes: a third inductor, an eighth capacitor, and a nineteenth switching transistor; One end of the third inductor is the first input terminal of the low-voltage output circuit; The other end of the third inductor is electrically connected to one end of the eighth capacitor and the source of the nineteenth switch. The gate of the nineteenth switch is electrically connected to the controller; The other end of the eighth capacitor is the second input terminal of the low-voltage output circuit. The drain of the nineteenth switching transistor is the first output terminal of the low-voltage output circuit. The second output terminal of the low-voltage output circuit is electrically connected to the other end of the eighth capacitor. The first and second output terminals of the low-voltage output circuit are used for electrical connection with the storage battery.

[0015] On the other hand, embodiments of the present invention provide a charger / discharger, including the above-described charger / discharger circuit.

[0016] On the other hand, embodiments of the present invention provide a vehicle, including: a vehicle controller, a battery management system, and the aforementioned charging and discharging machine.

[0017] Optionally, the battery management system is used to acquire the internal temperature of the power battery pack, and when the internal temperature is less than a temperature threshold, to mark the thermal management status of the power battery pack as needing to be heated and to send a need-to-heat signal to the vehicle controller. The charging and discharging machine is used to monitor its own heating status and receive the drive motor speed sent by the motor controller; if the drive motor speed is less than the speed threshold and the charging and discharging machine is not in a heating state, it sends a heating signal to the vehicle controller. The vehicle controller is used to send a heating enable signal to the charger / discharger based on the signal to be heated and the signal that can be heated; The charge / discharge machine is also used to heat the internal resistance of the power battery pack after receiving the heating enable signal.

[0018] Optionally, the battery management system is also used to send relevant parameters of the power battery pack to the charger / discharger; The charge / discharger is specifically used to generate a charging current, a discharging current, and a heating frequency of the charge / discharger based on the relevant parameters of the power battery pack after receiving the heating enable signal; and to heat the internal resistance of the power battery pack based on the charging current, the discharging current, and the heating frequency of the charge / discharger.

[0019] The charging / discharging machine circuit, charging / discharging machine, and vehicle technical solutions provided in this invention embodiment include: an input circuit, a bridgeless PFC circuit, a first capacitor, a DBSRC circuit, a fourth capacitor, a high-voltage output circuit, and a controller; the input terminal of the input circuit is electrically connected to an AC power supply; the output terminal of the input circuit is electrically connected to the bridgeless PFC circuit; the two ends of the first capacitor are respectively electrically connected to the first output terminal and the second output terminal of the bridgeless PFC circuit; the first output terminal of the bridgeless PFC circuit is also electrically connected to the first input terminal of the DBSRC circuit, and the second output terminal of the bridgeless PFC circuit is also electrically connected to the second input terminal of the DBSRC circuit. The input terminal is electrically connected; the two ends of the fourth capacitor are electrically connected to the first and second output terminals of the DBSRC circuit, respectively; the first output terminal of the DBSRC circuit is also electrically connected to the first input terminal of the high-voltage output circuit, and the second output terminal of the DBSRC circuit is also electrically connected to the second input terminal of the high-voltage output circuit; the output terminal of the high-voltage output circuit is used to connect to the power battery pack; the bridgeless PFC circuit and the DBSRC circuit are also electrically connected to the controller, which is used to control the DBSRC circuit to repeatedly charge and discharge the power battery pack to heat the internal resistance of the power battery pack, thereby reducing the heating cost of the power battery and improving battery life. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of a charger / discharger circuit provided in an embodiment of the present invention; Figure 2 This is a schematic diagram showing the connection between the output terminal of the high-voltage output circuit and the power battery pack in an embodiment of the present invention; Figure 3 A schematic diagram of another charging / discharging machine circuit provided in an embodiment of the present invention; Figure 4 A schematic diagram of a charger / discharger provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of a vehicle provided in an embodiment of the present invention. Detailed Implementation

[0021] To better understand the technical solution of the present invention, the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0022] It should be understood that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0023] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise.

[0024] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0025] This invention provides a solution for heating a power battery pack using an onboard charger / discharger. The onboard charger / discharger can not only charge the power battery and 12V battery of an electric vehicle and discharge the electric vehicle to the outside, but also heat the power battery at low temperatures. Moreover, the heating source is located inside the internal resistance of the power battery pack, resulting in fast heating and uniform heating, which is beneficial to improving the consistency and service life of the power battery pack. In addition, the power battery can be heated without increasing the cost of automotive parts, thus reducing costs.

[0026] Figure 1 This is a schematic diagram of a charge / discharger circuit provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the charger / discharger circuit includes: Input circuit, bridgeless PFC circuit, first capacitor C1, DBSRC circuit, fourth capacitor C4, high voltage output circuit and controller (controller not shown in the figure). The input terminal of the input circuit is used for electrical connection to an AC power source, such as... Figure 1 As shown, L represents the live wire and N represents the neutral wire. In this embodiment of the invention, the input terminal of the input circuit is also called the AC side of the charge / discharger circuit. The AC side is used to connect to 220V AC power, serving as the power input for the charge / discharger during charging and the power output for the vehicle when discharging externally.

[0027] The output terminal of the input circuit is electrically connected to the bridgeless PFC circuit; The two ends of the first capacitor C1 are electrically connected to the first output terminal and the second output terminal of the bridgeless PFC circuit, respectively. The first output terminal of the bridgeless PFC circuit is also electrically connected to the first input terminal of the DBSRC circuit, and the second output terminal of the bridgeless PFC circuit is also electrically connected to the second input terminal of the DBSRC circuit. The two ends of the fourth capacitor C4 are electrically connected to the first and second output terminals of the DBSRC circuit, respectively. The first output terminal of the DBSRC circuit is also electrically connected to the first input terminal of the high voltage output circuit, and the second output terminal of the DBSRC circuit is also electrically connected to the second input terminal of the high voltage output circuit. The output terminal of the high-voltage output circuit is used to connect to the power battery pack; The bridgeless PFC circuit and DBSRC circuit are also electrically connected to the controller. The controller is used to control the DBSRC circuit to repeatedly charge and discharge the power battery pack, thereby heating the internal resistance of the power battery pack. Since no additional heating parts are required, the heating cost is reduced. At the same time, heating the power battery pack by heating its internal resistance makes the heating more uniform, which is beneficial to battery consistency, delays the degradation of the power battery's health, and improves battery life.

[0028] This invention utilizes a DBSRC circuit to pulse-heat the power battery pack, thereby heating the power battery in low-temperature environments, improving the charging and discharging power of the power battery in low-temperature environments, and enhancing the user's charging and driving experience.

[0029] Furthermore, such as Figure 1 As shown, the bridgeless PFC circuit includes: a first switch Q1, a second switch Q2, a third switch Q3, and a fourth switch Q4; The gates of the first switch Q1, the second switch Q2, the third switch Q3, and the fourth switch Q4 are all electrically connected to the controller. The source of the first switch Q1 and the drain of the second switch Q2 are electrically connected, and the source of the third switch Q3 and the drain of the fourth switch Q4 are electrically connected. The drain of the first switch Q1 and the drain of the third switch Q3 are the first output terminals of the bridgeless PFC circuit, and the source of the second switch Q2 and the source of the fourth switch Q4 are the second output terminals of the bridgeless PFC circuit.

[0030] In this embodiment of the invention, the bridgeless PFC circuit adopts a bridgeless totem pole structure, using four switching transistors Q1 & Q2 and Q3 & Q4 to form the bridgeless PFC structure. Among them, Q1 and Q2 (high-frequency transistors) serve as a set of main switching transistors, and Q3 and Q4 (power frequency transistors) serve as another set of auxiliary switching transistors. The input AC current is filtered and stored through inductor L1 and capacitor C1. Then, the conduction and cutoff of the four switching transistors Q1, Q2, Q3, and Q4 shape the input current into a sine wave in phase with the input voltage, thereby improving the power factor.

[0031] Furthermore, such as Figure 1 As shown, the input circuit includes: a first filter circuit E1, a pre-charge circuit F, a first diode D1, a second diode D2, and a first inductor L1; The input terminal of the first filter circuit E1 is used to connect to the AC power supply. The first output terminal of the first filter circuit E1 is electrically connected to the input terminal of the pre-charge circuit F; The output terminal of the pre-charging circuit F is electrically connected to the anode of the first diode D1, the cathode of the second diode D2, and one end of the first inductor L1; The cathode of the first diode D1 is electrically connected to the first output terminal of the bridgeless PFC circuit. The anode of the second diode D2 is electrically connected to the second output terminal of the PFC circuit. The other end of the first inductor L1 is electrically connected to the source of the first switching transistor Q1 and the drain of the second switching transistor Q2. The second output terminal of the first filter circuit E1 is electrically connected to the source of the third switch Q3 and the drain of the fourth switch Q4.

[0032] Furthermore, the pre-charging circuit F consists of a resistor and a relay, with the relay electrically connected to the controller. The pre-charging circuit is a critical protection circuit in new energy vehicles, energy storage systems, and high-voltage electronic equipment. It is primarily used to limit initial surge current and prevent damage to components from the instantaneous large current generated when the high-voltage system is directly connected. Its core principle is to gradually charge the capacitive load through a current-limiting resistor, and then switch to the main circuit by controlling the relay once the voltage approaches the power supply voltage.

[0033] Furthermore, such as Figure 1 As shown, the DBSRC circuit includes: fifth switch Q5, sixth switch Q6, seventh switch Q7, eighth switch Q8, ninth switch Q9, tenth switch Q10, eleventh switch Q11, twelfth switch Q12, second capacitor C2, first transformer T1, second inductor L2 and third capacitor C3. The gates of the fifth switch Q5, the sixth switch Q6, the seventh switch Q7, the eighth switch Q8, the ninth switch Q9, the tenth switch Q10, the eleventh switch Q11, and the twelfth switch Q12 are all electrically connected to the controller. The source of the fifth switch Q5 is electrically connected to the drain of the sixth switch Q6, the source of the seventh switch Q7 is electrically connected to the drain of the eighth switch Q8, the source of the ninth switch Q9 is electrically connected to the drain of the tenth switch Q10, and the source of the eleventh switch Q11 is electrically connected to the drain of the twelfth switch Q12. The drain of the fifth switch Q5 and the drain of the seventh switch Q7 are the first input terminals of the DBSRC circuit, and the source of the sixth switch Q6 and the source of the eighth switch Q8 are the second input terminals of the DBSRC circuit. The drain of the ninth switch Q9 and the drain of the eleventh switch Q11 are the first output terminals of the DBSRC circuit, and the source of the tenth switch Q10 and the source of the twelfth switch Q12 are the second output terminals of the DBSRC circuit. The source of the fifth switch Q5 and the drain of the sixth switch Q6 are also electrically connected to one end of the second capacitor C1, and the other end of the second capacitor C1 is electrically connected to the first end of the primary terminal of the first transformer T1. The source of the seventh switch Q7 and the drain of the eighth switch Q8 are also electrically connected to one end of the second inductor L2, and the other end of the second inductor L2 is electrically connected to the second end of the primary terminal of the first transformer T1. The source of the ninth switch Q9 and the drain of the tenth switch Q10 are also electrically connected to one end of the third capacitor C3, and the other end of the third capacitor C3 is electrically connected to the first end of the secondary winding of the first transformer T1. The source of the eleventh switch Q11 and the drain of the twelfth switch Q12 are also electrically connected to the second terminal of the secondary winding of the first transformer T1.

[0034] In this embodiment of the invention, the DBSRC circuit consists of primary-side H1 bridges Q5, Q6, Q7, and Q8, and secondary-side H2 bridges Q9, Q10, Q11, and Q12. H1 and H2 are connected via the leakage inductance L2 of transformer T1, transformer T1, capacitor C2, and capacitor C3 to match the voltage difference between them. The leakage inductance L2 of the transformer serves as an instantaneous energy storage and transfer element. The phase of the two H bridges is adjusted to control the magnitude and direction of the converter's power transmission. Furthermore, the DBSRC circuit performs phase modulation control through inward and outward phase shift angles and frequency modulation control through the switching frequency. Combining phase modulation and frequency modulation control increases the degrees of freedom of the DBSRC circuit, thereby improving efficiency.

[0035] Furthermore, the charge / discharger circuit also includes: a voltage sensor, electrically connected to the first capacitor C1 and the controller; the voltage sensor is used to detect the voltage across the first capacitor C1 and send the voltage across the first capacitor C1 to the controller.

[0036] Furthermore, such as Figure 1 As shown, the controller is specifically used to: control the discharge of the power battery pack by turning on the fifth switch Q5, the eighth switch Q8, the ninth switch Q9 and the twelfth switch Q12; when the voltage across the first capacitor C1 is detected to be greater than a set threshold, the controller controls the fifth switch Q5, the sixth switch Q6, the seventh switch Q7, the eighth switch Q8, the ninth switch Q9, the tenth switch Q10, the eleventh switch Q11 and the twelfth switch Q12 to charge the power battery pack.

[0037] After the vehicle is powered on at high voltage, the battery management system issues a heating request based on the temperature and charge status of the power battery pack. The charge / discharge machine controls the Q5-Q12 bridge arm switches of the DBSRC circuit according to the heating request. By using the leakage inductance L2 of transformer T1, transformer T1, and capacitor C1 as instantaneous energy storage and transfer elements, the pulse heating request is achieved.

[0038] First, Q5 & Q8 and Q9 & Q12 are turned on, allowing the battery pack to charge the leakage inductance L2, transformer T1, and capacitor C1 of the charger / discharger via the DC voltage of the bus (HV+, HV-). At this time, the battery pack is in discharge mode, and the discharge current direction is set to positive. After the battery pack has finished charging the energy storage elements of the charger / discharger, the charger / discharger controls the Q5-Q8 and Q9-Q12 bridge arms to use transformer T1, leakage inductance L2, and capacitor C2 in series resonance to boost the voltage and charge the battery pack. At this time, the battery pack current direction is negative, thus completing one cycle of applying alternating current in both positive and negative directions across the battery pack. It is through the continuous charging and discharging of the energy storage elements in the DBSRC circuit of the charger / discharger that the internal resistance of the battery pack is energized, thereby heating the battery.

[0039] Furthermore, such as Figure 1 As shown, the high-voltage output circuit includes: the second filter circuit E2 and the seventh capacitor C7; The first input terminal of the second filter circuit E2 is the first input terminal of the high voltage output circuit, and the second input terminal of the second filter circuit E2 is the second input terminal of the high voltage output circuit. The first output terminal of the second filter circuit E2 is electrically connected to one end of the first capacitor C7 and is also used for electrical connection to the positive terminal of the power battery pack; the second output terminal of the second filter circuit E2 is electrically connected to the other end of the first capacitor C7 and is also used for electrical connection to the negative terminal of the power battery pack.

[0040] For example, Figure 2 This is a schematic diagram showing the connection between the output terminal of the high-voltage output circuit and the power battery pack in an embodiment of the present invention, as shown below. Figure 2 As shown, the first output terminal HV+ of the high-voltage output circuit is electrically connected to the positive terminal of the power battery inside the power battery pack, the negative terminal of the power battery is electrically connected to one end of the internal resistor, and the other end of the internal resistor is electrically connected to the second output terminal HV- of the high-voltage output circuit.

[0041] In this embodiment of the invention, the output terminal of the high-voltage output circuit is also referred to as the high-voltage battery side of the charge / discharger circuit. The high-voltage battery side of the charge / discharger is connected to a power battery pack (such as a lithium-ion power battery pack) for charging the power battery. The power battery pack consists of multiple series of cells connected in series. Each cell has its own internal resistance. The power battery contains electrical energy, and the Joule heat generated when the electrical energy of the power battery pack flows through the internal resistance of the cells is used to heat the power battery pack.

[0042] Furthermore, Figure 3 This is a schematic diagram of another charging / discharging machine circuit provided in an embodiment of the present invention, compared to... Figure 1 The charger / discharger circuit shown is as follows: Figure 3 As shown, the charger circuit also includes: the fifth capacitor C5, a hard-switching full-bridge circuit, the sixth capacitor C6, the second transformer T2, the seventeenth switch Q17, the eighteenth switch Q18, and a low-voltage output circuit. The first output terminal of the DBSRC circuit is also electrically connected to one end of the fifth capacitor C5 and the first input terminal of the hard-switching full-bridge circuit; the second output terminal of the DBSRC circuit is also electrically connected to the other end of the fifth capacitor C5 and the second input terminal of the hard-switching full-bridge circuit. The first output terminal of the hard-switching full-bridge circuit is electrically connected to one end of the sixth capacitor C6, and the other end of the sixth capacitor C6 is electrically connected to the first terminal of the primary of the second transformer T2; the second output terminal of the hard-switching full-bridge circuit is electrically connected to the second terminal of the primary of the second transformer T2. The first terminal of the secondary winding of the second transformer T2 is electrically connected to the drain of the seventeenth switching transistor Q17; the second terminal of the secondary winding of the second transformer T2 is electrically connected to the drain of the eighteenth switching transistor Q18. The third terminal of the secondary winding of the second transformer T2 is electrically connected to the first input terminal of the low-voltage output circuit; wherein, the third terminal of the secondary winding of the second transformer T2 is located between the first terminal and the second segment of the secondary winding of the second transformer T2. The source of the seventeenth switch Q17 and the source of the eighteenth switch Q18 are electrically connected to the second input terminal of the low-voltage output circuit. The gates of the seventeenth switch Q17 and the eighteenth switch Q18 are electrically connected to the controller.

[0043] Furthermore, such as Figure 3As shown, the hard-switching full-bridge circuit includes: the thirteenth switch Q13, the fourteenth switch Q14, the fifteenth switch Q15, and the sixteenth switch Q16; The gates of the thirteenth switch Q13, the fourteenth switch Q14, the fifteenth switch Q15, and the sixteenth switch Q16 are all electrically connected to the controller. The source of the thirteenth switch Q13 and the drain of the fourteenth switch Q14 are electrically connected, and the source of the fifteenth switch Q15 and the drain of the sixteenth switch Q16 are electrically connected. The drain of the thirteenth switch Q13 and the drain of the fifteenth switch Q15 are the first input terminals of the hard-switching full-bridge circuit, and the source of the fourteenth switch Q14 and the source of the sixteenth switch Q16 are the second input terminals of the hard-switching full-bridge circuit. The source of the thirteenth switch Q13 and the drain of the fourteenth switch Q14 are electrically connected to the sixth capacitor C6. The source of the fifteenth switch Q15 and the drain of the sixteenth switch Q16 are electrically connected to the second terminal of the primary terminal of the second transformer T2.

[0044] In this embodiment of the invention, the primary-side main switches Q13 & Q16 and Q14 & Q15 of the hard-switching full-bridge circuit form a full-bridge structure. Q13 and Q16 are simultaneously turned on as one diagonal pair, and Q14 and Q15 are simultaneously turned on as another diagonal pair. The output voltage is controlled and adjusted by adjusting the duty cycle of the primary-side full-bridge MOSFETs. The voltage generated by the rectifier network on the secondary side of transformer T2 is rectified by synchronous rectifier MOSFETs Q17-Q18. The rectifier network Q17-Q18 is designed for full-wave synchronous rectification.

[0045] Furthermore, such as Figure 3 As shown, the low-voltage output circuit includes: the third inductor L3, the eighth capacitor C8, and the nineteenth switching transistor Q19; One end of the third inductor L3 is the first input terminal of the low-voltage output circuit; The other end of the third inductor L3 is electrically connected to one end of the eighth capacitor C8 and the source of the nineteenth switch Q19. The gate of the nineteenth switching transistor Q19 is electrically connected to the controller; The other end of the eighth capacitor C8 is the second input terminal of the low-voltage output circuit; The drain of the nineteenth switching transistor Q19 is the first output terminal LV+ of the low-voltage output circuit; The second output terminal LV- of the low-voltage output circuit is electrically connected to the other end of the eighth capacitor C8. The first output terminal LV+ and the second output terminal LV- of the low-voltage output circuit are used for electrical connection with the battery.

[0046] In this embodiment of the invention, the output terminal of the low-voltage output circuit is also called the low-voltage battery side of the charger circuit, which is used to connect a 12V battery to charge it.

[0047] In this embodiment of the invention, the high-voltage battery side of the charger / discharger circuit is also used to supply power to the primary circuit of the low-voltage battery side.

[0048] In this embodiment of the invention, Figure 1 and Figure 3 All the switching transistors shown can be IGBTs (Insulated Gate Bipolar Transistors) or MOS transistors (Metal-Oxide-Semiconductor Field-Effect Transistors), etc.

[0049] In the technical solution provided by this invention, the charge / discharge machine circuit includes: an input circuit, a bridgeless PFC circuit, a first capacitor, a DBSRC circuit, a fourth capacitor, a high-voltage output circuit, and a controller. The input terminal of the input circuit is electrically connected to an AC power source. The output terminal of the input circuit is electrically connected to the bridgeless PFC circuit. The two ends of the first capacitor are electrically connected to the first and second output terminals of the bridgeless PFC circuit, respectively. The first output terminal of the bridgeless PFC circuit is also electrically connected to the first input terminal of the DBSRC circuit, and the second output terminal of the bridgeless PFC circuit is also electrically connected to the second input terminal of the DBSRC circuit. The two ends of the fourth capacitor are respectively electrically connected to the first and second output terminals of the DBSRC circuit. The first output terminal of the DBSRC circuit is also electrically connected to the first input terminal of the high-voltage output circuit, and the second output terminal of the DBSRC circuit is also electrically connected to the second input terminal of the high-voltage output circuit. The output terminal of the high-voltage output circuit is connected to the power battery pack. The bridgeless PFC circuit and the DBSRC circuit are also electrically connected to the controller. The controller is used to control the DBSRC circuit to repeatedly charge and discharge the power battery pack to heat the internal resistance of the power battery pack, thereby reducing the heating cost of the power battery and improving battery life.

[0050] Figure 4 This is a schematic diagram of a charge / discharge machine provided in an embodiment of the present invention, as shown below. Figure 4 As shown, the charger / discharger includes the charger / discharger circuit in the above circuit embodiment.

[0051] Figure 5 A schematic diagram of a vehicle provided as an embodiment of the present invention, such as... Figure 5 As shown, the vehicle includes: a vehicle controller, a battery management system, and... Figure 4 The charger / discharger shown.

[0052] The battery management system is used to obtain the internal temperature of the power battery pack. When the internal temperature is lower than the temperature threshold, the thermal management status of the power battery pack is marked as needing to be heated and a heating signal is sent to the vehicle controller.

[0053] When the vehicle is powered on but not in motion, the internal temperature sensor of the power battery pack monitors the internal temperature of the battery pack in real time. If the internal temperature is lower than the temperature threshold (which can be calibrated), the BMS (Battery Management System) marks the thermal management status of the power battery pack as "to be heated" and uploads the "to be heated" signal to the vehicle controller (VCU).

[0054] The charger / discharger monitors its own heating status and receives the drive motor speed from the motor controller. If the drive motor speed is less than the speed threshold and the charger / discharger is not in a heating state, it sends a heating signal to the vehicle controller.

[0055] The charger / discharger's controller monitors its own fault status in real time. If the charger / discharger has no serious faults (such as overheating, short circuit, insulation failure, etc.), it performs a self-test and enters normal operation. The charger / discharger monitors its own heating status in real time and receives the drive motor speed signal sent by the motor controller. If the drive motor speed is less than the speed threshold (which can be calibrated, such as 20 rpm) and the charger / discharger is not in heating mode, it sends a "heatable" signal to the VCU.

[0056] The vehicle controller is used to send a heating enable signal to the charge / discharge machine based on the signal to be heated and the signal that it can be heated.

[0057] After receiving the "to be heated" signal from the BMS and the "can be heated" signal from the charger, the VCU sends a "heating enable" signal to the charger.

[0058] The charger is also used to heat the internal resistance of the power battery pack after receiving a heating enable signal.

[0059] In this embodiment of the invention, the battery management system is also used to send relevant parameters of the power battery pack to the charger / discharger.

[0060] Based on the battery's internal temperature, initial performance of the battery pack, and current health status, the BMS calculates in real time the charging and discharging current thresholds and the allowable charging and discharging frequency thresholds of the power battery pack using a lookup table method (pre-calibrated), and sends the relevant parameters of the power battery pack to the charger / discharger in the form of an upload signal.

[0061] Specifically, the charge / discharger is used to generate the charging current, discharging current, and heating frequency of the power battery pack based on the relevant parameters of the power battery pack after receiving the heating enable signal; and to heat the internal resistance of the power battery pack based on the charging current, discharging current, and heating frequency of the charge / discharger.

[0062] After receiving the "heating enable" signal from the VCU, the charger calculates the charging and discharging current and frequency boundary MAP based on the battery's minimum temperature, allowable charging and discharging current, allowable charging and discharging frequency, charger switching frequency, voltage utilization, etc. The charger then looks up the maximum charging and discharging current value in the table based on the MAP and heats the battery according to the set heating frequency.

[0063] The rules for controlling the charge / discharge machine are as follows: 1) The discharge current of the charger / discharger is less than the allowable charging current of the battery pack; 2) Charger / discharger current < battery pack allowable discharge current; 3) The charging / discharging frequency is less than the allowable frequency of the battery pack.

[0064] This invention implements low-temperature battery pack heating technology through charge / discharge machine control. The heating source is located inside the battery pack's internal resistance, resulting in fast and uniform heating, which helps improve the battery pack's consistency and lifespan. Under the same energy consumption, the charge / discharge machine's heating efficiency is superior to PTC (Positive Temperature Coefficient) heating. No additional external heating components are needed, thus reducing costs.

[0065] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A charge / discharger circuit, characterized in that, include: Input circuit, bridgeless PFC circuit, first capacitor, DBSRC circuit, fourth capacitor, high voltage output circuit and controller; The input terminal of the input circuit is used for electrical connection with an AC power source; The output terminal of the input circuit is electrically connected to the bridgeless PFC circuit. The two ends of the first capacitor are electrically connected to the first output terminal and the second output terminal of the bridgeless PFC circuit, respectively. The first output terminal of the bridgeless PFC circuit is also electrically connected to the first input terminal of the DBSRC circuit, and the second output terminal of the bridgeless PFC circuit is also electrically connected to the second input terminal of the DBSRC circuit. The two ends of the fourth capacitor are electrically connected to the first output terminal and the second output terminal of the DBSRC circuit, respectively. The first output terminal of the DBSRC circuit is also electrically connected to the first input terminal of the high voltage output circuit, and the second output terminal of the DBSRC circuit is also electrically connected to the second input terminal of the high voltage output circuit. The output terminal of the high-voltage output circuit is used to connect to the power battery pack. The bridgeless PFC circuit and the DBSRC circuit are also electrically connected to the controller. The controller is used to control the DBSRC circuit to repeatedly charge and discharge the power battery pack in order to heat the internal resistance of the power battery pack.

2. The charge / discharger circuit according to claim 1, characterized in that, The bridgeless PFC circuit includes: a first switching transistor, a second switching transistor, a third switching transistor, and a fourth switching transistor; The gates of the first switch, the second switch, the third switch, and the fourth switch are all electrically connected to the controller; The source of the first switching transistor and the drain of the second switching transistor are electrically connected, and the source of the third switching transistor and the drain of the fourth switching transistor are electrically connected. The drain of the first switch and the drain of the third switch are the first output terminals of the bridgeless PFC circuit, and the source of the second switch and the source of the fourth switch are the second output terminals of the bridgeless PFC circuit.

3. The charge / discharger circuit according to claim 2, characterized in that, The input circuit includes: a first filter circuit, a pre-charge circuit, a first diode, a second diode, and a first inductor; The input terminal of the first filter circuit is used to be electrically connected to the AC power supply; The first output terminal of the first filter circuit is electrically connected to the input terminal of the pre-charging circuit. The output terminal of the pre-charging circuit is electrically connected to the anode of the first diode, the cathode of the second diode, and one end of the first inductor. The cathode of the first diode is electrically connected to the first output terminal of the bridgeless PFC circuit; The anode of the second diode is electrically connected to the second output terminal of the PFC circuit; The other end of the first inductor is electrically connected to the source of the first switching transistor and the drain of the second switching transistor; The second output terminal of the first filter circuit is electrically connected to the source of the third switch and the drain of the fourth switch.

4. The charge / discharger circuit according to claim 1, characterized in that, The DBSRC circuit includes: a fifth switch, a sixth switch, a seventh switch, an eighth switch, a ninth switch, a tenth switch, an eleventh switch, a twelfth switch, a second capacitor, a first transformer, a second inductor, and a third capacitor; The gates of the fifth, sixth, seventh, eighth, ninth, tenth, eleventh, and twelfth switching transistors are all electrically connected to the controller. The source of the fifth switch is electrically connected to the drain of the sixth switch, the source of the seventh switch is electrically connected to the drain of the eighth switch, the source of the ninth switch is electrically connected to the drain of the tenth switch, and the source of the eleventh switch is electrically connected to the drain of the twelfth switch. The drain of the fifth switch and the drain of the seventh switch are the first input terminals of the DBSRC circuit, and the source of the sixth switch and the source of the eighth switch are the second input terminals of the DBSRC circuit. The drain of the ninth switch and the drain of the eleventh switch are the first output terminals of the DBSRC circuit, and the source of the tenth switch and the source of the twelfth switch are the second output terminals of the DBSRC circuit. The source of the fifth switch and the drain of the sixth switch are also electrically connected to one end of the second capacitor, and the other end of the second capacitor is electrically connected to the first end of the primary terminal of the first transformer. The source of the seventh switch and the drain of the eighth switch are also electrically connected to one end of the second inductor, and the other end of the second inductor is electrically connected to the second end of the primary terminal of the first transformer. The source of the ninth switch and the drain of the tenth switch are also electrically connected to one end of the third capacitor, and the other end of the third capacitor is electrically connected to the first end of the secondary winding of the first transformer. The source of the eleventh switch and the drain of the twelfth switch are also electrically connected to the second terminal of the secondary winding of the first transformer.

5. The charge / discharger circuit according to claim 4, characterized in that, The charge / discharger circuit further includes a voltage sensor, which is electrically connected to the first capacitor and the controller; the voltage sensor is used to detect the voltage across the first capacitor and send the voltage across the first capacitor to the controller.

6. The charge / discharger circuit according to claim 5, characterized in that, The controller is specifically used for: The power battery pack is controlled to discharge by turning on the fifth, eighth, ninth, and twelfth switches. When the voltage across the first capacitor is detected to be greater than a set threshold, the power battery pack is charged by controlling the fifth, sixth, seventh, eighth, ninth, tenth, eleventh, and twelfth switching transistors.

7. The charge / discharger circuit according to claim 4, characterized in that, The high-voltage output circuit includes: a second filter circuit and a seventh capacitor; The first input terminal of the second filter circuit is the first input terminal of the high voltage output circuit, and the second input terminal of the second filter circuit is the second input terminal of the high voltage output circuit. The first output terminal of the second filter circuit is electrically connected to one end of the first capacitor and is also used to electrically connect to the positive terminal of the power battery pack; the second output terminal of the second filter circuit is electrically connected to the other end of the first capacitor and is also used to electrically connect to the negative terminal of the power battery pack.

8. The charge / discharger circuit according to claim 1, characterized in that, The charging and discharging machine circuit also includes: a fifth capacitor, a hard-switching full-bridge circuit, a sixth capacitor, a second transformer, a seventeenth switching transistor, an eighteenth switching transistor, and a low-voltage output circuit; The first output terminal of the DBSRC circuit is also electrically connected to one end of the fifth capacitor and the first input terminal of the hard-switching full-bridge circuit; the second output terminal of the DBSRC circuit is also electrically connected to the other end of the fifth capacitor and the second input terminal of the hard-switching full-bridge circuit. The first output terminal of the hard-switching full-bridge circuit is electrically connected to one end of the sixth capacitor, and the other end of the sixth capacitor is electrically connected to the first terminal of the primary winding of the second transformer; the second output terminal of the hard-switching full-bridge circuit is electrically connected to the second terminal of the primary winding of the second transformer. The first terminal of the secondary winding of the second transformer is electrically connected to the drain of the seventeenth switching transistor; the second terminal of the secondary winding of the second transformer is electrically connected to the drain of the eighteenth switching transistor. The third terminal of the secondary winding of the second transformer is electrically connected to the first input terminal of the low-voltage output circuit; the source terminals of the seventeenth and eighteenth switching transistors are electrically connected to the second input terminal of the low-voltage output circuit. The gates of the seventeenth and eighteenth switching transistors are electrically connected to the controller.

9. The charge / discharger circuit according to claim 8, characterized in that, The hard-switching full-bridge circuit includes: a thirteenth switch, a fourteenth switch, a fifteenth switch, and a sixteenth switch; The gates of the thirteenth, fourteenth, fifteenth, and sixteenth switching transistors are all electrically connected to the controller. The source of the thirteenth switch and the drain of the fourteenth switch are electrically connected, and the source of the fifteenth switch and the drain of the sixteenth switch are electrically connected. The drain of the thirteenth switch and the drain of the fifteenth switch are the first input terminals of the hard-switching full-bridge circuit, and the source of the fourteenth switch and the source of the sixteenth switch are the second input terminals of the hard-switching full-bridge circuit. The source of the thirteenth switch and the drain of the fourteenth switch are electrically connected to the sixth capacitor. The source of the fifteenth switch and the drain of the sixteenth switch are electrically connected to the second terminal of the primary terminal of the second transformer.

10. The charge / discharger circuit according to claim 8, characterized in that, The low-voltage output circuit includes: a third inductor, an eighth capacitor, and a nineteenth switching transistor; One end of the third inductor is the first input terminal of the low-voltage output circuit; The other end of the third inductor is electrically connected to one end of the eighth capacitor and the source of the nineteenth switch. The gate of the nineteenth switch is electrically connected to the controller; The other end of the eighth capacitor is the second input terminal of the low-voltage output circuit. The drain of the nineteenth switching transistor is the first output terminal of the low-voltage output circuit. The second output terminal of the low-voltage output circuit is electrically connected to the other end of the eighth capacitor. The first and second output terminals of the low-voltage output circuit are used for electrical connection with the storage battery.

11. A charge / discharge machine, characterized in that, include: The charger / discharger circuit as described in any one of claims 1-10.

12. A vehicle, characterized in that, include: The vehicle controller, the battery management system, and the charger / discharger as described in claim 11.

13. The vehicle according to claim 12, characterized in that, The battery management system is used to obtain the internal temperature of the power battery pack. When the internal temperature is less than a temperature threshold, the thermal management status of the power battery pack is marked as needing to be heated and a need-to-heat signal is sent to the vehicle controller. The charging and discharging machine is used to monitor its own heating status and receive the drive motor speed sent by the motor controller; if the drive motor speed is less than the speed threshold and the charging and discharging machine is not in a heating state, it sends a heating signal to the vehicle controller. The vehicle controller is used to send a heating enable signal to the charger / discharger based on the signal to be heated and the signal that can be heated; The charge / discharge machine is also used to heat the internal resistance of the power battery pack after receiving the heating enable signal.

14. The vehicle according to claim 13, characterized in that, The battery management system is also used to send relevant parameters of the power battery pack to the charger / discharger; The charge / discharger is specifically used to generate a charging current, a discharging current, and a heating frequency of the charge / discharger based on the relevant parameters of the power battery pack after receiving the heating enable signal; and to heat the internal resistance of the power battery pack based on the charging current, the discharging current, and the heating frequency of the charge / discharger.

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