Vehicle battery charging device, charging method and vehicle

Abstract

The invention discloses a vehicle battery charging device and method and a vehicle, the vehicle battery charging device comprises a controller, a first switch and a converter arranged between a power battery and a fast charging interface of the vehicle, and the converter comprises a first bridge arm, a second bridge arm and a third bridge arm; the two ends of the first bridge arm, the second bridge arm and the third bridge arm are respectively connected with the power battery and the quick charging interface, the midpoints of the first bridge arm, the second bridge arm and the third bridge arm are respectively connected with a winding of a three-phase motor of a vehicle, and one end of the first bridge arm is connected with one end of the second bridge arm through the first switch; the controller is connected with the converter and the first switch and used for obtaining the maximum output voltage of the charging pile, the minimum charging voltage of the battery and / or the environment temperature when the fast charging interface is connected to the charging pile, controlling the converter and the first switch and switching the working mode of the power battery. According to the invention, the functions of up-current charging, direct charging and boost charging can be realized, the pulse heating function of the low-temperature power battery can be compatible, and the cost is low.

Description

Technical Field

[0001] This invention relates to the field of automotive technology, and more particularly to a vehicle battery charging device, charging method, and vehicle. Background Technology

[0002] With the development of the new energy vehicle industry, power systems are constantly evolving towards miniaturization, lightweighting, and low cost, and the demand for fast charging in electric vehicles is increasing. Existing charging systems are mostly fixed topologies, unable to simultaneously meet the boost and current requirements under different charging pile maximum output voltage conditions, while also being compatible with battery pack pulse heating. Furthermore, existing charging systems are complex, bulky, and costly. Therefore, there is an urgent need for a multifunctional, low-cost system that can achieve boost, current boost, pass-through, and pulse heating within the same circuit topology. Summary of the Invention

[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a vehicle battery charging device, charging method and vehicle that can realize both boost charging and boost charging, while also being compatible with the pulse heating function of low-temperature power batteries, so as to meet the rapid energy replenishment needs of different scenarios.

[0004] The present invention provides a vehicle battery charging device, including a controller, a first switch, and a converter disposed between the power battery and the vehicle's fast charging interface. The converter includes a first bridge arm, a second bridge arm, and a third bridge arm. The two ends of the first bridge arm, the second bridge arm, and the third bridge arm are respectively connected to the power battery and the fast charging interface. The midpoints of the first bridge arm, the second bridge arm, and the third bridge arm are respectively connected to the windings of the vehicle's three-phase motor. One end of the first bridge arm and one end of the second bridge arm are connected through the first switch. The controller is connected to the converter and the first switch respectively. When the fast charging interface is connected to the charging pile, the controller is used to obtain the maximum output voltage of the charging pile, the minimum charging voltage of the power battery and / or the ambient temperature, and control the converter and the first switch according to the maximum output voltage of the charging pile, the minimum charging voltage of the battery and / or the ambient temperature to switch the working mode of the power battery. The working mode includes boost charging mode, direct charging mode, boost charging mode and pulse heating mode.

[0005] In one of the alternative technical solutions, the controller is further configured to: If the maximum output voltage of the charging pile is greater than the minimum charging voltage of the battery, and the output current of the charging pile is limited, the first switch is opened, the upper bridge arm of the first bridge arm is turned on, the lower bridge arm of the first bridge arm is opened, and the upper and lower bridge arms of the second and third bridge arms are intermittently turned on. The first switch, the converter, and the windings of the three-phase motor form a Buck circuit, so that the power battery is in the boost charging mode.

[0006] In one of the alternative technical solutions, the controller is further configured to: If the maximum output voltage of the charging pile is greater than the minimum charging voltage of the battery, and the output current of the charging pile is not limited, the first switch is closed, and the first bridge arm, the second bridge arm, and the third bridge arm are disconnected, so that the power battery is in the direct charging mode.

[0007] In one of the alternative technical solutions, the controller is further configured to: If the maximum output voltage of the charging pile is less than or equal to the minimum charging voltage of the battery, and the output current of the charging pile is limited, the first switch is opened, the upper and lower bridge arms of the first bridge arm are intermittently connected, the upper bridge arms of the second and third bridge arms are connected, and the lower bridge arms of the second and third bridge arms are disconnected. The first switch, the converter, and the windings of the three-phase motor form a Boost circuit, so that the power battery is in the boost charging mode.

[0008] In one of the alternative technical solutions, the controller is further configured to: If the ambient temperature is lower than a preset temperature threshold, the first switch is closed, the second bridge arm is disconnected, and the upper and lower bridge arms of the first and third bridge arms are intermittently connected, so that the power battery is in the pulse heating mode.

[0009] The present invention also provides a charging method for a vehicle battery charging device as described in any of the foregoing descriptions, comprising: Obtain the maximum output voltage of the charging pile, the minimum charging voltage of the power battery, and / or the ambient temperature; The converter and the first switch are controlled according to the maximum output voltage of the charging pile, the minimum charging voltage of the battery and / or the ambient temperature to switch the working mode of the power battery. The working modes include boost charging mode, direct charging mode, boost charging mode and pulse heating mode.

[0010] In one alternative technical solution, controlling the converter and the first switch to switch the operating mode of the power battery based on the maximum output voltage of the charging pile, the minimum charging voltage of the battery, and / or the ambient temperature includes: If the maximum output voltage of the charging pile is greater than the minimum charging voltage of the battery, and the output current of the charging pile is limited, the first switch is opened, the upper bridge arm of the first bridge arm is turned on, the lower bridge arm of the first bridge arm is opened, and the upper and lower bridge arms of the second and third bridge arms are intermittently turned on. The first switch, the converter, and the windings of the three-phase motor form a Buck circuit, so that the power battery is in the boost charging mode.

[0011] In one alternative technical solution, controlling the converter and the first switch to switch the operating mode of the power battery based on the maximum output voltage of the charging pile, the minimum charging voltage of the battery, and / or the ambient temperature includes: If the maximum output voltage of the charging pile is greater than the minimum charging voltage of the battery, and the output current of the charging pile is not limited, the first switch is closed, and the first bridge arm, the second bridge arm, and the third bridge arm are disconnected, so that the power battery is in the direct charging mode.

[0012] In one alternative technical solution, controlling the converter and the first switch to switch the operating mode of the power battery based on the maximum output voltage of the charging pile, the minimum charging voltage of the battery, and / or the ambient temperature includes: If the maximum output voltage of the charging pile is less than or equal to the minimum charging voltage of the battery, and the output current of the charging pile is limited, the first switch is opened, the upper and lower bridge arms of the first bridge arm are intermittently connected, the upper bridge arms of the second and third bridge arms are connected, and the lower bridge arms of the second and third bridge arms are disconnected. The first switch, the converter, and the windings of the three-phase motor form a Boost circuit, so that the power battery is in the boost charging mode.

[0013] In one alternative technical solution, controlling the converter and the first switch to switch the operating mode of the power battery based on the maximum output voltage of the charging pile, the minimum charging voltage of the battery, and / or the ambient temperature includes: If the ambient temperature is lower than a preset temperature threshold, the first switch is closed, the second bridge arm is disconnected, and the upper and lower bridge arms of the first and third bridge arms are intermittently connected, so that the power battery is in the pulse heating mode.

[0014] The present invention also provides a vehicle, including a power battery, a fast charging interface connected to a charging pile, and a vehicle battery charging device as described in any of the foregoing descriptions, wherein the converter of the vehicle battery charging device is disposed between the power battery and the fast charging interface.

[0015] The above technical solution has the following advantages: By controlling the controller, the first switch and the converter, the working mode of the power battery can be switched according to the maximum output voltage of the charging pile, the minimum charging voltage of the battery and / or the ambient temperature. It can realize the functions of boost charging, direct charging and boost charging, and can also be compatible with the pulse heating function of low temperature power batteries, so as to meet the rapid energy replenishment needs of different scenarios. At the same time, it reuses the original EPT system of the vehicle to the maximum extent. Different functions can be switched and controlled by adding only one switch, which is low cost. Attached Figure Description

[0016] The disclosure of this invention will become more readily understood by referring to the accompanying drawings. It should be understood that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings: Figure 1 This is a schematic diagram of the structure of a vehicle battery charging device according to an embodiment of the present invention; Figure 2 for Figure 1 A circuit diagram of a vehicle battery charging device; Figure 3 for Figure 1 A schematic diagram of the vehicle battery charging device in boost charging mode; Figure 4a for Figure 3 Status indication of the vehicle battery charging device Figure 1 ; Figure 4b for Figure 3 Status indication of the vehicle battery charging device Figure 2 ; Figure 5 for Figure 1 A schematic diagram of the vehicle battery charging device in direct charging mode; Figure 6 for Figure 1 A schematic diagram of the vehicle battery charging device in boost charging mode; Figure 6a for Figure 6 Status indication of the vehicle battery charging device Figure 1 ; Figure 6b for Figure 6 Status indication of the vehicle battery charging device Figure 2 ; Figure 7 for Figure 1 A schematic diagram of the vehicle battery charging device in pulse heating mode; Figure 7a for Figure 7 Status indication of the vehicle battery charging device Figure 1 ; Figure 7b for Figure 7 Status indication of the vehicle battery charging device Figure 2 ; Figure 8 This is a flowchart illustrating a vehicle battery charging method according to an embodiment of the present invention. Figure 9 This is a flowchart illustrating a vehicle battery charging method according to a preferred embodiment of the present invention. Detailed Implementation

[0017] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0018] It is readily understood that, based on the technical solution of this invention, various structural and implementation methods can be interchanged by those skilled in the art without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of the invention.

[0019] The directional terms such as up, down, left, right, front, back, front, back, top, and bottom mentioned or possibly used in this specification are defined relative to the structures shown in the accompanying drawings. They are relative concepts and may therefore vary depending on their location and usage. Therefore, these or other directional terms should not be interpreted as restrictive.

[0020] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a vehicle battery charging device 10, including a controller 11, a first switch K3, and a converter 12 disposed between a power battery 20 and a fast charging interface 30 of the vehicle. The converter 12 includes a first bridge arm, a second bridge arm, and a third bridge arm. The two ends of the first bridge arm, the second bridge arm, and the third bridge arm are respectively connected to the power battery 20 and the fast charging interface 30. The midpoints of the first bridge arm, the second bridge arm, and the third bridge arm are respectively connected to the windings of the vehicle's three-phase motor 40. One end of the first bridge arm and the second bridge arm are connected through the first switch K3. The controller 11 is connected to the converter 12 and the first switch K3 respectively. When the fast charging interface 30 is connected to the charging pile, the controller 11 is used to obtain the maximum output voltage of the charging pile, the minimum charging voltage of the power battery 20 and / or the ambient temperature, and control the converter 12 and the first switch K3 according to the maximum output voltage of the charging pile, the minimum charging voltage of the battery and / or the ambient temperature to switch the working mode of the power battery 20. The working mode includes boost charging mode, direct charging mode, boost charging mode and pulse heating mode.

[0021] This invention is mainly applied to charging systems for electric vehicles, such as... Figure 2 As shown, the prior art charging system includes a power battery 20, a fast charging interface 30, and a three-phase motor 40, wherein the windings of the three-phase motor 40 are represented by L1, L2, and L3, respectively.

[0022] The vehicle battery charging device 10 provided in this embodiment of the invention mainly includes a controller 11, a first switch K3, and a converter 12. The converter 12 in this embodiment can be an existing charging system converter. Only the first switch K3 needs to be installed between the upper arms of the first and second bridge arms of the existing converter 12. The first switch K3 enables the switching and control of different functions (including boost charging, direct charging, boost charging, and pulse heating), maximizing the reuse of the vehicle's original electric power train (EPT) system at a low cost.

[0023] The converter 12 is connected between the power battery 20 and the vehicle's fast charging interface 30. The converter 12 includes a first bridge arm, a second bridge arm and a third bridge arm. The first bridge arm includes a first power switch Q1 and a second power switch Q2. The second bridge arm includes a third power switch Q3 and a fourth power switch Q4. The third bridge arm includes a fifth power switch Q5 and a sixth power switch Q6.

[0024] One end of the first power switch Q1, the third power switch Q3, and the fifth power switch Q5 are respectively connected to the main positive relay K5 of the power battery 20 and the fast charging positive relay K1 of the fast charging port 30. One end of the second power switch Q1, the fourth power switch Q4, and the sixth power switch Q6 are respectively connected to the main negative relay K6 of the power battery 20 and the fast charging negative relay K2 of the fast charging port 30. The midpoint of the first power switch Q1 and the second power switch Q2 is connected to the winding L3. The midpoint of the third power switch Q3 and the fourth power switch Q4 is connected to the winding L1. The midpoint of the fifth power switch Q5 and the sixth power switch Q6 is connected to the winding L2. One end of the first power switch Q1 and the third power switch Q3 are connected through the first switch K3. When the power battery 20 is charging, the main positive relay K5, the main negative relay K6, the fast charging positive relay K1, and the fast charging negative relay K2 are closed; when the power battery 20 is fully charged, the main positive relay K5, the main negative relay K6, the fast charging positive relay K1, and the fast charging negative relay K2 are open.

[0025] The controller 11 is connected to the converter 12 and the first switch K3 respectively. When the fast charging interface 30 is connected to the charging pile, the controller 11 is used to obtain the maximum output voltage of the charging pile, the preset minimum charging voltage of the power battery 20 and / or the ambient temperature by reading the maximum output capability message (CML message) sent by the charging pile. The controller 11 controls the converter 12 and the first switch K3 according to the maximum output voltage of the charging pile, the minimum charging voltage of the battery and / or the ambient temperature to switch the working mode of the power battery 20. The working modes include boost charging mode, direct charging mode, boost charging mode and pulse heating mode.

[0026] When the power battery 20 is in the boost charging mode, the main positive relay K5, the main negative relay K6, the fast charging positive relay K1, and the fast charging negative relay K2 are closed. The controller 11 controls the converter 12 to enter the buck-boost mode. The power battery is charged while the windings L1, L2, and L3 are being charged. After the windings L1, L2, and L3 are fully charged, the windings L1, L2, and L3, along with the charging pile, simultaneously charge the power battery 20, achieving boost charging, reducing charging time, and improving charging efficiency.

[0027] When the power battery 20 is in direct charging mode, the main positive relay K5, the main negative relay K6, the fast charging positive relay K1 and the fast charging negative relay K2 are closed, the controller 11 controls the converter 12 to not work, and the charging pile directly charges the power battery 20 through the fast charging interface 30 to avoid the converter 12 from working damage.

[0028] When the power battery 20 is in boost charging mode, the main positive relay K5, main negative relay K6, fast charging positive relay K1, and fast charging negative relay K2 are closed. The controller 11 controls the converter 12 to enter boost mode. The charging pile first charges the windings L1, L2, and L3 through the fast charging port 30. After the windings L1, L2, and L3 have completed charging, the windings L1, L2, and L3 and the charging pile charge the power battery 20 simultaneously, achieving boost charging and enabling compatibility with low-voltage charging piles.

[0029] When the power battery 20 is in pulse heating mode, the main positive relay K5 and the main negative relay K6 are closed, and the fast charging positive relay K1 and the fast charging negative relay K2 are open. The controller 11 controls the converter 12 to make the power battery 20 first discharge the windings L1, L2 and L3. After the windings L1, L2 and L3 are fully charged, the power battery 20 is charged. The power battery 20 completes one discharge → charge cycle. This cycle is repeated to make the power battery 20 perform intermittent charging and discharging, thereby realizing the pulse heating function of the power battery 20 and preventing the power battery 20 from being in a low-temperature environment, which would affect the battery life.

[0030] The vehicle battery charging device provided in this embodiment controls the converter and the first switch according to the maximum output voltage of the charging pile, the minimum charging voltage of the battery and / or the ambient temperature to switch the working mode of the power battery. It can realize the functions of boost charging, direct charging and boost charging, and is also compatible with the pulse heating function of low temperature power batteries to meet the rapid energy replenishment needs of different scenarios. At the same time, it reuses the original EPT system of the vehicle to the maximum extent. Different functions can be switched and controlled by adding only one switch, which is low cost.

[0031] In one embodiment, the controller 11 is further configured to: If the maximum output voltage of the charging pile is greater than the minimum charging voltage of the battery, and the output current of the charging pile is limited, the first switch K3 is opened, the upper bridge arm Q1 of the first bridge arm is turned on, the lower bridge arm Q2 of the first bridge arm is opened, and the upper bridge arms Q3 and Q5 and the lower bridge arms Q4 and Q6 of the second and third bridge arms are intermittently turned on. The first switch K3, the converter 12, and the windings L1, L2, and L3 of the three-phase motor form a Buck circuit, so that the power battery 20 is in the boost charging mode.

[0032] When controller 11 obtains the maximum output voltage of the charging pile and the minimum charging voltage of the battery, it determines whether the maximum output voltage of the charging pile is greater than the minimum charging voltage of the battery, and whether the output current of the charging pile is limited. If so, it controls the main positive relay K5, the main negative relay K6, the fast charging positive relay K1, and the fast charging negative relay K2 to close, and the first switch K3 to open, forming a Buck circuit. Figure 3As shown, controller 11 then controls the first power switch Q1 to turn on, and the second power switch Q2, the fourth power switch Q4, and the sixth power switch Q6 to turn off. Based on the calculated duty cycle (D5), controller 11 controls the third power switch Q3 and the fifth power switch Q5 to turn on. At this time, the state of the vehicle battery charging device is as follows: Figure 4a As shown, the current flows through two closed loops sequentially: 1) Fast charging port 30 → K1 → Q3 → L1 → L3 → Q1 → K5 → Power battery 20 → K6 → Fast charging port 30; 2) Fast charging port 30 → K1 → Q5 → L2 → L3 → Q1 → K5 → Power battery 20 → K6 → Fast charging port 30, enabling the charging pile to charge windings L1, L2, L3 and power battery 20; then, controller 11 controls the third power switch Q3 and the fifth power switch Q5 to disconnect, and controls the fourth power switch Q4 and the sixth power switch Q6 to conduct according to the duty cycle (1-D5). At this time, the state of the vehicle battery charging device is as follows. Figure 4b As shown, the current also flows through two closed loops in sequence: 3) L1→L3→Q1→K5→Power Battery 20→K6→Q6→L2; 4) L2→L3→Q1→K5→Power Battery 20→K6→Q4→L1, so that the charging pile charges the power battery 20 while charging the windings L1, L2 and L3 of the three-phase motor 30. After the windings L1, L2 and L3 of the three-phase motor 30 are charged, the electric battery 20 is charged again, realizing the power battery boost charging function, reducing charging time and improving charging efficiency.

[0033] The duty cycle D5 can be calculated using existing technology and is not an improvement of this application, so it will not be elaborated here.

[0034] In one embodiment, the controller 11 is further configured to: If the maximum output voltage of the charging pile is greater than the minimum charging voltage of the battery, and the output current of the charging pile is not limited, the first switch K3 is closed, and the first bridge arm, the second bridge arm and the third bridge arm are disconnected, so that the power battery 20 is in the direct charging mode.

[0035] When controller 11 obtains the maximum output voltage of the charging pile and the minimum charging voltage of the battery, it determines whether the maximum output voltage of the charging pile is greater than the minimum charging voltage of the battery, and whether the output current of the charging pile is unrestricted. If so, it controls the main positive relay K5, main negative relay K6, fast charging positive relay K1, and fast charging negative relay K2 to close, and the first switch K3 to close, and the circuit is as follows. Figure 5 As shown, at this time, the converter 12 is not working, and the current charging pile directly charges the electric battery 20 through the fast charging port 30 to realize the direct charging function and avoid converter working losses.

[0036] In one embodiment, the controller 11 is further configured to: If the maximum output voltage of the charging pile is less than or equal to the minimum charging voltage of the battery, and the output current of the charging pile is limited, the first switch K3 is opened, the upper bridge arm Q1 and the lower bridge arm Q2 of the first bridge arm are intermittently connected, the upper bridge arms Q3 and Q5 of the second bridge arm and the third bridge arm are connected, and the lower bridge arms Q4 and Q6 of the second bridge arm and the third bridge arm are opened. The first switch K3, the converter 12, and the windings L1, L2, and L3 of the three-phase motor form a Boost circuit, so that the power battery 20 is in the boost charging mode.

[0037] When controller 11 obtains the maximum output voltage of the charging pile and the minimum charging voltage of the battery, it determines whether the maximum output voltage of the charging pile is less than or equal to the minimum charging voltage of the battery, and whether the output current of the charging pile is limited. If so, it controls the main positive relay K5, main negative relay K6, fast charging positive relay K1, and fast charging negative relay K2 to close, and the first switch K3 to open, forming a Boost circuit. Figure 6 As shown, controller 11 then controls the third power switch Q3 and the fifth power switch Q5 to turn on, while the first power switch Q1, the fourth power switch Q4, and the sixth power switch Q6 are turned off. Based on the calculated duty cycle (D1), controller 11 controls the second power switch Q2 to turn on. At this time, the state of the vehicle battery charging device is as follows: Figure 6a As shown, the current flows through two closed loops in sequence: 1) Fast charging port 30 → K1 → Q3 → L1 → L3 → Q2 → K2 → Fast charging port 30; 2) Fast charging port 30 → K1 → Q5 → L2 → L3 → Q2 → K2 → Fast charging port 30, causing the charging pile to charge windings L1, L2, and L3 first; then the controller 11 controls the second power switch Q2 to turn off, and controls the first power switch Q1 to turn on according to the duty cycle (1-D1). At this time, the state of the vehicle battery charging device is as follows. Figure 6b As shown, the current also passes through four closed loops in sequence: 3) Fast charging port 30 → K1 → Q3 → L1 → L3 → Q1 → K5 → Power battery 20 → K6 → K2 → Fast charging port 30; 4) Fast charging port 30 → K1 → Q5 → L2 → L3 → Q1 → K5 → Power battery 20 → K6 → K2 → Fast charging port 30; 5) L1 → L3 → Q1 → K5 → Power battery 30 → K6 → K2 → Fast charging port 30; 6) L2 → L3 → Q1 → K5 → Power battery 20 → K6 → K2 → Fast charging port 30, so that the windings L1, L2 and L3 of the charging pile and the three-phase motor 30 charge the power battery 20 simultaneously, realizing the power battery boost charging function and being compatible with low-voltage charging piles.

[0038] The duty cycle D1 can be calculated using existing technology and is not an improvement of this application, so it will not be elaborated here.

[0039] In one embodiment, the controller 11 is further configured to: If the ambient temperature is less than a preset temperature threshold, the first switch K3 is closed, the second bridge arms Q3 and Q4 are opened, and the upper bridge arms Q1 and Q5 and the lower bridge arms Q2 and Q6 of the first and third bridge arms are intermittently connected, so that the power battery 20 is in the pulse heating mode.

[0040] When controller 11 receives the ambient temperature detected by the temperature sensor, it determines whether the ambient temperature is lower than a preset temperature threshold. If so, it indicates that the vehicle is in a low-temperature environment. It then closes the main positive relay K5 and the main negative relay K6, opens the fast-charging positive relay K1 and the fast-charging negative relay K2, and closes the first switch K3. At this time, the vehicle battery charging device is in pulse heating mode. Figure 7 As shown, the second power switch Q2, the third power switch Q3, the fourth power switch Q4, and the fifth power switch Q5 are then disconnected, while the first power switch Q1 and the sixth power switch Q6 are closed. At this time, the state of the vehicle battery charging device is as follows. Figure 7a As shown, the current flows through the closed loop: power battery 20 → K5 → Q1 → L3 → L2 → Q6 → K6 → power battery 20, causing power battery 20 to charge windings L3 and L2; then the controller controls the first power switch Q1 and the sixth power switch Q6 to disconnect, and the second power switch Q2 and the fifth power switch Q5 to conduct. At this time, the state of the vehicle battery charging device is as follows. Figure 7b As shown, the current direction in windings L3 and L2 remains unchanged, and the current in windings L3 and L2 continues to flow through the high-voltage circuit: Q5→K3→K5→power battery 20→K6→Q2→L3→L2→Q5. Windings L3 and L2 charge the power battery 20. This cycle repeats, and the power battery 20 undergoes intermittent charging and discharging, generating heat to achieve the power battery pulse heating function, thus avoiding the impact of low-temperature environments on the service life of the power battery.

[0041] The closing time of the first power switch Q1 and the sixth power switch Q6 can be calculated using existing technology based on the working voltage of the power battery 20, the maximum allowable charging current, and the inductive energy storage of the windings L1-L3. This is not an improvement point of this application and will not be elaborated here.

[0042] like Figure 8 As shown, the present invention also provides a charging method for a vehicle battery charging device as described in any of the foregoing descriptions, comprising: Step S801: Obtain the maximum output voltage of the charging pile, the minimum charging voltage of the power battery, and / or the ambient temperature; Step S802: Control the converter and the first switch according to the maximum output voltage of the charging pile, the minimum charging voltage of the battery and / or the ambient temperature to switch the working mode of the power battery. The working mode includes boost charging mode, direct charging mode, boost charging mode and pulse heating mode.

[0043] Specifically, when the charging pile is successfully connected to the fast charging port, the controller executes step S801 to obtain the maximum output voltage of the charging pile, the preset minimum charging voltage of the power battery, and / or the ambient temperature by reading the maximum output capability message (CML message) sent by the charging pile, and then executes step S802 to control the converter and the first switch according to the maximum output voltage of the charging pile, the minimum charging voltage of the battery, and / or the ambient temperature to switch the working mode of the power battery. The working modes include boost charging mode, direct charging mode, boost charging mode, and pulse heating mode.

[0044] The vehicle battery charging method provided in this embodiment obtains the maximum output voltage of the charging pile, the minimum charging voltage of the power battery, and / or the ambient temperature. Based on the maximum output voltage of the charging pile, the minimum charging voltage of the battery, and / or the ambient temperature, it controls the converter and the first switch to switch the working mode of the power battery. This method can realize the functions of boost charging, direct charging, and boost charging, and is also compatible with the pulse heating function of low-temperature power batteries, meeting the rapid energy replenishment needs of different scenarios. At the same time, it reuses the original EPT system of the vehicle to the greatest extent. Different functions can be switched and controlled by adding only one switch, which is low cost.

[0045] In one embodiment, step S802 includes: If the maximum output voltage of the charging pile is greater than the minimum charging voltage of the battery, and the output current of the charging pile is limited, the first switch is opened, the upper bridge arm of the first bridge arm is turned on, the lower bridge arm of the first bridge arm is opened, and the upper and lower bridge arms of the second and third bridge arms are intermittently turned on. The first switch, the converter, and the windings of the three-phase motor form a Buck circuit, so that the power battery is in the boost charging mode.

[0046] Specifically, when the controller obtains the maximum output voltage of the charging pile and the minimum charging voltage of the battery, it determines whether the maximum output voltage of the charging pile is greater than the minimum charging voltage of the battery, and whether the output current of the charging pile is limited. If so, it controls the main positive relay K5, the main negative relay K6, the fast charging positive relay K1, and the fast charging negative relay K2 to close, and the first switch K3 to open, forming a Buck circuit. Figure 3As shown, controller 11 then controls the first power switch Q1 to turn on, and the second power switch Q2, the fourth power switch Q4, and the sixth power switch Q6 to turn off. Based on the calculated duty cycle (D5), controller 11 controls the third power switch Q3 and the fifth power switch Q5 to turn on. At this time, the state of the vehicle battery charging device is as follows: Figure 4a As shown, the current flows through two closed loops sequentially: 1) Fast charging port 30 → K1 → Q3 → L1 → L3 → Q1 → K5 → Power battery 20 → K6 → Fast charging port 30; 2) Fast charging port 30 → K1 → Q5 → L2 → L3 → Q1 → K5 → Power battery 20 → K6 → Fast charging port 30, enabling the charging pile to charge windings L1, L2, L3 and power battery 20; then, controller 11 controls the third power switch Q3 and the fifth power switch Q5 to disconnect, and controls the fourth power switch Q4 and the sixth power switch Q6 to conduct according to the duty cycle (1-D5). At this time, the state of the vehicle battery charging device is as follows. Figure 4b As shown, the current also flows through two closed loops in sequence: 3) L1→L3→Q1→K5→Power Battery 20→K6→Q6→L2; 4) L2→L3→Q1→K5→Power Battery 20→K6→Q4→L1, so that the charging pile charges the power battery 20 while charging the windings L1, L2 and L3 of the three-phase motor 30. After the windings L1, L2 and L3 of the three-phase motor 30 are charged, the electric battery 20 is charged again, realizing the power battery boost charging function, reducing charging time and improving charging efficiency.

[0047] The duty cycle D5 can be calculated using existing technology and is not an improvement of this application, so it will not be elaborated here.

[0048] In one embodiment, step S802 includes: If the maximum output voltage of the charging pile is greater than the minimum charging voltage of the battery, and the output current of the charging pile is not limited, the first switch is closed, and the first bridge arm, the second bridge arm, and the third bridge arm are disconnected, so that the power battery is in the direct charging mode.

[0049] Specifically, when the controller obtains the maximum output voltage of the charging pile and the minimum charging voltage of the battery, it determines whether the maximum output voltage of the charging pile is greater than the minimum charging voltage of the battery, and whether the output current of the charging pile is unrestricted. If so, it controls the main positive relay K5, main negative relay K6, fast charging positive relay K1, and fast charging negative relay K2 to close, and the first switch K3 to close, and the circuit is as follows. Figure 5 As shown, at this time, the converter 12 is not working, and the current charging pile directly charges the electric battery 20 through the fast charging port 30 to realize the direct charging function and avoid converter working losses.

[0050] In one embodiment, step S802 includes: If the maximum output voltage of the charging pile is less than or equal to the minimum charging voltage of the battery, and the output current of the charging pile is limited, the first switch is opened, the upper and lower bridge arms of the first bridge arm are intermittently connected, the upper bridge arms of the second and third bridge arms are connected, and the lower bridge arms of the second and third bridge arms are disconnected. The first switch, the converter, and the windings of the three-phase motor form a Boost circuit, so that the power battery is in the boost charging mode.

[0051] Specifically, when the controller obtains the maximum output voltage of the charging pile and the minimum charging voltage of the battery, it determines whether the maximum output voltage of the charging pile is less than or equal to the minimum charging voltage of the battery, and whether the output current of the charging pile is limited. If so, it controls the main positive relay K5, main negative relay K6, fast charging positive relay K1, and fast charging negative relay K2 to close, and the first switch K3 to open, forming a Boost circuit. Figure 6 As shown, controller 11 then controls the third power switch Q3 and the fifth power switch Q5 to turn on, while the first power switch Q1, the fourth power switch Q4, and the sixth power switch Q6 are turned off. Based on the calculated duty cycle (D1), controller 11 controls the second power switch Q2 to turn on. At this time, the state of the vehicle battery charging device is as follows: Figure 6a As shown, the current flows through two closed loops in sequence: 1) Fast charging port 30 → K1 → Q3 → L1 → L3 → Q2 → K2 → Fast charging port 30; 2) Fast charging port 30 → K1 → Q5 → L2 → L3 → Q2 → K2 → Fast charging port 30, causing the charging pile to charge windings L1, L2, and L3 first; then the controller 11 controls the second power switch Q2 to turn off, and controls the first power switch Q1 to turn on according to the duty cycle (1-D1). At this time, the state of the vehicle battery charging device is as follows. Figure 6b As shown, the current also passes through four closed loops in sequence: 3) Fast charging port 30 → K1 → Q3 → L1 → L3 → Q1 → K5 → Power battery 20 → K6 → K2 → Fast charging port 30; 4) Fast charging port 30 → K1 → Q5 → L2 → L3 → Q1 → K5 → Power battery 20 → K6 → K2 → Fast charging port 30; 5) L1 → L3 → Q1 → K5 → Power battery 30 → K6 → K2 → Fast charging port 30; 6) L2 → L3 → Q1 → K5 → Power battery 20 → K6 → K2 → Fast charging port 30, so that the windings L1, L2 and L3 of the charging pile and the three-phase motor 30 charge the power battery 20 simultaneously, realizing the power battery boost charging function and being compatible with low-voltage charging piles.

[0052] The duty cycle D1 can be calculated using existing technology and is not an improvement of this application, so it will not be elaborated here.

[0053] In one embodiment, step S802 includes: If the ambient temperature is lower than a preset temperature threshold, the first switch is closed, the second bridge arm is disconnected, and the upper and lower bridge arms of the first and third bridge arms are intermittently connected, so that the power battery is in the pulse heating mode.

[0054] Specifically, when the controller receives the ambient temperature detected by the temperature sensor, it determines whether the ambient temperature is lower than a preset temperature threshold. If so, it indicates that the vehicle is in a low-temperature environment. The controller then closes the main positive relay K5 and the main negative relay K6, opens the fast-charging positive relay K1 and the fast-charging negative relay K2, and closes the first switch K3. At this time, the vehicle's battery charging device is in pulse heating mode. Figure 7 As shown, the second power switch Q2, the third power switch Q3, the fourth power switch Q4, and the fifth power switch Q5 are then disconnected, while the first power switch Q1 and the sixth power switch Q6 are closed. At this time, the state of the vehicle battery charging device is as follows. Figure 7a As shown, the current flows through the closed loop: power battery 20 → K5 → Q1 → L3 → L2 → Q6 → K6 → power battery 20, causing power battery 20 to charge windings L3 and L2; then the controller controls the first power switch Q1 and the sixth power switch Q6 to disconnect, and the second power switch Q2 and the fifth power switch Q5 to conduct. At this time, the state of the vehicle battery charging device is as follows. Figure 7b As shown, the current direction in windings L3 and L2 remains unchanged, and the current in windings L3 and L2 continues to flow through the high-voltage circuit: Q5→K3→K5→power battery 20→K6→Q2→L3→L2→Q5. Windings L3 and L2 charge the power battery 20. This cycle repeats, and the power battery 20 undergoes intermittent charging and discharging, generating heat to achieve the power battery pulse heating function, thus avoiding the impact of low-temperature environments on the service life of the power battery.

[0055] The closing time of the first power switch Q1 and the sixth power switch Q6 can be calculated using existing technology based on the working voltage of the power battery 20, the maximum allowable charging current, and the inductive energy storage of the windings L1-L3. This is not an improvement point of this application and will not be elaborated here.

[0056] like Figure 9 As shown, a preferred embodiment of the present invention provides a vehicle battery charging method, comprising: Step S901: Insert the gun; Step S902: Determine whether the charging handshake was successful. If yes, proceed to step S903; otherwise, end. Step S903: Read the CML message indicating the maximum output capacity of the charging pile; Step S904: Determine whether the maximum output voltage of the charging pile is less than or equal to the minimum charging voltage of the battery. If yes, proceed to step S905; otherwise, proceed to step S906. Step S905: Control K3 to disconnect, K1 and K2 to close, control the vehicle to enter boost charging mode, and the converter and three-phase motor are in Boost mode; Step S906: Determine whether the maximum output voltage of the charging pile is greater than the minimum charging voltage of the battery and less than the maximum charging voltage of the battery. If so, proceed to step S907; otherwise, proceed to step S910. Step S907: Determine whether the real-time charging voltage of the charging pile is less than or equal to the maximum output voltage of the charging pile. If yes, proceed to step S908; otherwise, proceed to step S905. Step S908: Determine whether the supercharging mode is enabled. If yes, proceed to step S910; otherwise, proceed to step S909. Step S909: Control K1, K2, and K3 to close, and enter the direct charging mode; Step S910: Control K3 to disconnect, K1 and K2 to close, control the vehicle to enter the boost charging mode, and the converter and three-phase motor are in Buck mode; Step S911: Determine if the power battery is fully charged. If yes, end; otherwise, continue to step S904.

[0057] The present invention also provides a vehicle, including a power battery, a fast charging interface connected to a charging pile, and a vehicle battery charging device as described in any of the foregoing descriptions, wherein the converter of the vehicle battery charging device is disposed between the power battery and the fast charging interface.

[0058] The above embodiments are only used to illustrate the technical solutions of the embodiments of the present invention, and are not intended to limit them. Although the embodiments of the present invention have been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A vehicle battery charging device, characterized in that, This includes a controller, a first switch, and a converter positioned between the power battery and the vehicle's fast-charging interface. The converter includes a first bridge arm, a second bridge arm, and a third bridge arm. The two ends of the first bridge arm, the second bridge arm, and the third bridge arm are respectively connected to the power battery and the fast charging interface. The midpoints of the first bridge arm, the second bridge arm, and the third bridge arm are respectively connected to the windings of the vehicle's three-phase motor. One end of the first bridge arm and one end of the second bridge arm are connected through the first switch. The controller is connected to the converter and the first switch respectively. When the fast charging interface is connected to the charging pile, the controller is used to obtain the maximum output voltage of the charging pile, the minimum charging voltage of the power battery and / or the ambient temperature, and control the converter and the first switch according to the maximum output voltage of the charging pile, the minimum charging voltage of the battery and / or the ambient temperature to switch the working mode of the power battery. The working mode includes boost charging mode, direct charging mode, boost charging mode and pulse heating mode.

2. The vehicle battery charging device as described in claim 1, characterized in that, The controller is also used for: If the maximum output voltage of the charging pile is greater than the minimum charging voltage of the battery, and the output current of the charging pile is limited, the first switch is opened, the upper bridge arm of the first bridge arm is turned on, the lower bridge arm of the first bridge arm is opened, and the upper and lower bridge arms of the second and third bridge arms are intermittently turned on. The first switch, the converter, and the windings of the three-phase motor form a Buck circuit, so that the power battery is in the boost charging mode.

3. The vehicle battery charging device as described in claim 1, characterized in that, The controller is also used for: If the maximum output voltage of the charging pile is greater than the minimum charging voltage of the battery, and the output current of the charging pile is not limited, the first switch is closed, and the first bridge arm, the second bridge arm, and the third bridge arm are disconnected, so that the power battery is in the direct charging mode.

4. The vehicle battery charging device as described in claim 1, characterized in that, The controller is also used for: If the maximum output voltage of the charging pile is less than or equal to the minimum charging voltage of the battery, and the output current of the charging pile is limited, the first switch is opened, the upper and lower bridge arms of the first bridge arm are intermittently connected, the upper bridge arms of the second and third bridge arms are connected, and the lower bridge arms of the second and third bridge arms are disconnected. The first switch, the converter, and the windings of the three-phase motor form a Boost circuit, so that the power battery is in the boost charging mode.

5. The vehicle battery charging device according to any one of claims 1-4, characterized in that, The controller is also used for: If the ambient temperature is lower than a preset temperature threshold, the first switch is closed, the second bridge arm is disconnected, and the upper and lower bridge arms of the first and third bridge arms are intermittently connected, so that the power battery is in the pulse heating mode.

6. A charging method for a vehicle battery charging device as described in any one of claims 1-5, characterized in that, include: Obtain the maximum output voltage of the charging pile, the minimum charging voltage of the power battery, and / or the ambient temperature; The converter and the first switch are controlled according to the maximum output voltage of the charging pile, the minimum charging voltage of the battery and / or the ambient temperature to switch the working mode of the power battery. The working modes include boost charging mode, direct charging mode, boost charging mode and pulse heating mode.

7. The charging method as described in claim 6, characterized in that, The step of controlling the converter and the first switch according to the maximum output voltage of the charging pile, the minimum charging voltage of the battery, and / or the ambient temperature to switch the operating mode of the power battery includes: If the maximum output voltage of the charging pile is greater than the minimum charging voltage of the battery, and the output current of the charging pile is limited, the first switch is opened, the upper bridge arm of the first bridge arm is turned on, the lower bridge arm of the first bridge arm is opened, and the upper and lower bridge arms of the second and third bridge arms are intermittently turned on. The first switch, the converter, and the windings of the three-phase motor form a Buck circuit, so that the power battery is in the boost charging mode.

8. The charging method as described in claim 6, characterized in that, The step of controlling the converter and the first switch according to the maximum output voltage of the charging pile, the minimum charging voltage of the battery, and / or the ambient temperature to switch the operating mode of the power battery includes: If the maximum output voltage of the charging pile is greater than the minimum charging voltage of the battery, and the output current of the charging pile is not limited, the first switch is closed, and the first bridge arm, the second bridge arm, and the third bridge arm are disconnected, so that the power battery is in the direct charging mode.

9. The charging method as described in claim 6, characterized in that, The step of controlling the converter and the first switch according to the maximum output voltage of the charging pile, the minimum charging voltage of the battery, and / or the ambient temperature to switch the operating mode of the power battery includes: If the maximum output voltage of the charging pile is less than or equal to the minimum charging voltage of the battery, and the output current of the charging pile is limited, the first switch is opened, the upper and lower bridge arms of the first bridge arm are intermittently connected, the upper bridge arms of the second and third bridge arms are connected, and the lower bridge arms of the second and third bridge arms are disconnected. The first switch, the converter, and the windings of the three-phase motor form a Boost circuit, so that the power battery is in the boost charging mode.

10. The charging method according to any one of claims 6-9, characterized in that, The step of controlling the converter and the first switch according to the maximum output voltage of the charging pile, the minimum charging voltage of the battery, and / or the ambient temperature to switch the operating mode of the power battery includes: If the ambient temperature is lower than a preset temperature threshold, the first switch is closed, the second bridge arm is disconnected, and the upper and lower bridge arms of the first and third bridge arms are intermittently connected, so that the power battery is in the pulse heating mode.

11. A vehicle, characterized in that, It includes a power battery, a fast charging interface connected to a charging pile, and a vehicle battery charging device as described in any one of claims 1-5, wherein the converter of the vehicle battery charging device is disposed between the power battery and the fast charging interface.

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