High-voltage battery system for a vehicle, control method thereof, and vehicle

Abstract

This disclosure relates to a high-voltage battery system for a vehicle, comprising: at least two high-voltage batteries (110, 120) having the same rated voltage, the at least two high-voltage batteries being installed in the vehicle and configured to supply power to the vehicle's drive unit; a switching unit (200) capable of connecting the at least two high-voltage batteries (110, 120) in parallel or in series; and a controller (300) configured to connect the at least two high-voltage batteries (110, 120) in series when the vehicle is connected to an external charging device to charge the at least two high-voltage batteries (110, 120). Additionally, this disclosure relates to a corresponding method for controlling the high-voltage battery system for a vehicle and a corresponding vehicle.

Description

Technical Field

[0001] This disclosure relates to a high-voltage battery system for a vehicle, a control method thereof, and a vehicle. Background Technology

[0002] Significantly reducing the fast charging time for electric vehicles remains a challenge, especially given the existence of different vehicle voltage levels (e.g., 400V, 800V) and different charging infrastructures (e.g., 500V, 750V, 950V / 1000V).

[0003] Currently, the mainstream voltage level for electric vehicles is 400V, while some high-end brands are beginning to reach 800V. On the other hand, most charging infrastructure before 2017 was 500V, while newer charging infrastructure is primarily 750V, with a smaller proportion of new fast-charging infrastructure at 950V / 1000V. When charging a 400V electric vehicle through a 750V (or 950V / 1000V) charging infrastructure, the infrastructure will not be fully utilized. When charging an 800V electric vehicle through a 500V or 750V charging infrastructure, the vehicle will not be fully charged.

[0004] Therefore, with existing technologies, vehicles and charging infrastructure cannot be effectively matched, which leads to limited use of charging sources and long charging times. Summary of the Invention

[0005] In view of this, the present disclosure provides a high-voltage battery system for vehicles and a control method thereof, which can significantly shorten charging time. Furthermore, the high-voltage battery system and control method according to the present disclosure can effectively utilize the charging source.

[0006] According to a first aspect of this disclosure, a high-voltage battery system for a vehicle is provided, the high-voltage battery system comprising: at least two high-voltage batteries having the same rated voltage, the at least two high-voltage batteries being installable in the vehicle and configured to supply power to a drive unit of the vehicle; a switching unit capable of connecting the at least two high-voltage batteries in parallel or in series; and a controller configured to connect the at least two high-voltage batteries in series when the vehicle is connected to an external charging device to charge the at least two high-voltage batteries.

[0007] Therefore, the high-voltage battery system according to this disclosure can be matched with charging devices having different output voltages. Furthermore, regardless of whether the output voltage of the external charging device is higher or lower than the rated voltage of the high-voltage battery, the individual high-voltage batteries are first connected in series to charge the high-voltage battery system. This allows for rapid charging of the high-voltage battery system, significantly reducing charging time. This is because, for a single cell, the charging current in series connection is greater than that in parallel connection, resulting in a faster charging speed; consequently, the charging speed of the entire high-voltage battery system is also greater. Especially when the output voltage of the external charging device is approximately twice or higher than the vehicle's rated drive voltage, connecting at least two high-voltage batteries in series significantly increases the charging speed, thereby shortening the charging time.

[0008] Preferably, the controller may also be configured to: when the vehicle is connected to an external charging device to charge the at least two high-voltage batteries, after the at least two high-voltage batteries are connected in series, if the output voltage of the external charging device is greater than the series voltage of the at least two high-voltage batteries, then maintain the series connection of the at least two high-voltage batteries until the state of charge of the at least two high-voltage batteries reaches 100%; if the output voltage of the external charging device is less than or equal to the series voltage of the at least two high-voltage batteries, then connect the at least two high-voltage batteries in parallel after a preset condition is met, until the state of charge of the at least two high-voltage batteries reaches 100%.

[0009] In this regard, preferably, the preset conditions may be: the state of charge of the at least two high-voltage batteries remains unchanged for a period of time; and / or if the output voltage of the external charging device is close to p times the rated voltage of the high-voltage battery, p≥1, then the state of charge of the at least two high-voltage batteries reaches 40p%; and / or the charged voltage of the at least two high-voltage batteries is more than 90% of the output voltage of the external charging device.

[0010] Therefore, not only can the charging speed be increased, but the output voltage of the external charging device can also be fully utilized. In particular, when the output voltage of the external charging device is only about half or higher than the vehicle's rated drive voltage, the high-voltage battery can be fully charged by connecting at least two high-voltage batteries in parallel.

[0011] Preferably, the controller can also be configured to disconnect all switches of the switching unit when the vehicle is neither charging nor being driven. This can improve the safety of the high-voltage battery system.

[0012] Preferably, the switching unit may include 2×(n-1) parallel switches and n-1 series switches, where n equals the number of high-voltage batteries. One parallel switch is connected to the positive output terminal of one high-voltage battery on one side and to the positive output terminal of the next high-voltage battery on the other side. Another parallel switch is connected to the negative output terminal of the first high-voltage battery on one side and to the negative output terminal of the next high-voltage battery on the other side. A series switch is connected to the negative output terminal of the first high-voltage battery on one side and to the positive output terminal of the next high-voltage battery on the other side. This provides a simple way to achieve the series and parallel electrical connections of the high-voltage batteries in the high-voltage battery system.

[0013] Preferably, the controller can also be configured to prevent the parallel switch from closing when the series switch is closed, and to prevent the series switch from closing when the parallel switch is closed. This achieves an interlock function between series and parallel connections, thereby improving the safety of the high-voltage battery system.

[0014] Preferably, the high-voltage battery system further includes a pre-charge unit. This prevents excessive surge current from the higher-voltage battery to the lower-voltage battery when there are voltage differences between the individual high-voltage batteries. Therefore, so-called soft-start can be achieved, thereby improving the safety of the high-voltage battery system.

[0015] According to a second aspect of this disclosure, a method for controlling a high-voltage battery system for a vehicle is provided. The method includes the steps of: determining whether charging of at least two high-voltage batteries in the high-voltage battery system is required; when charging of the at least two high-voltage batteries is required, connecting the at least two high-voltage batteries in series; if the output voltage of the external charging device is greater than the series voltage of the at least two high-voltage batteries, maintaining the series connection of the at least two high-voltage batteries until the state of charge of the at least two high-voltage batteries reaches 100%; if the output voltage of the external charging device is less than or equal to the series voltage of the at least two high-voltage batteries, connecting the at least two high-voltage batteries in parallel after satisfying a preset condition, until the state of charge of the at least two high-voltage batteries reaches 100%.

[0016] Preferably, the preset conditions are: the state of charge of the at least two high-voltage batteries remains unchanged for a period of time; and / or if the output voltage of the external charging device is close to p times the rated voltage of the high-voltage battery, p≥1, then the state of charge of the at least two high-voltage batteries reaches 40p%; and / or the charged voltage of the at least two high-voltage batteries is more than 90% of the output voltage of the external charging device.

[0017] According to a third aspect of this disclosure, a vehicle is provided having a high-voltage battery system according to this disclosure and / or being configured to implement the methods according to this disclosure. Preferably, the vehicle is a purely electric vehicle.

[0018] The methods and vehicles for controlling high-voltage battery systems according to the second and third aspects of this disclosure also bring the same advantages as the high-voltage battery systems for vehicles according to the first aspect of this disclosure, which will not be repeated here. Attached Figure Description

[0019] To make the above-mentioned objectives, features and advantages of this disclosure more apparent and understandable, the specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings.

[0020] Figure 1 A configuration diagram of a high-voltage battery system for a vehicle according to an exemplary embodiment of the present disclosure is shown.

[0021] Figure 2 A configuration diagram of a high-voltage battery system for a vehicle in series configuration according to an exemplary embodiment of the present disclosure is shown.

[0022] Figure 3 A configuration diagram of a high-voltage battery system for a vehicle in parallel configuration according to an exemplary embodiment of the present disclosure is shown.

[0023] Figure 4 A flowchart illustrating a control method for a high-voltage battery system for a vehicle according to an exemplary embodiment of the present disclosure is shown. Detailed Implementation

[0024] Specific details are set forth in the following description to provide a full understanding of the invention. However, the invention can be practiced in many ways other than those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0025] The following will describe in detail, with reference to the accompanying drawings, an exemplary embodiment of a high-voltage battery system for a vehicle and a control method thereof according to the present disclosure.

[0026] like Figure 1 As shown, a high-voltage battery system for a vehicle according to this disclosure may include at least two high-voltage batteries having the same rated voltage, which can be installed in a vehicle and configured to supply power to the vehicle's drive unit, such as a drive motor. In this embodiment, the high-voltage battery system includes two high-voltage batteries, namely a first high-voltage battery 110 and a second high-voltage battery 120.

[0027] Each high-voltage battery is a rechargeable battery installed in the vehicle and capable of storing electrical energy. Each high-voltage battery may have multiple battery cells. Each battery cell is composed of a rechargeable battery capable of charging and discharging, such as a lithium-ion battery. The battery cells may be arranged side by side and connected in series with each other.

[0028] The rated voltage of each high-voltage battery can be equal to the vehicle's rated drive voltage or 1 / m of the vehicle's rated drive voltage, where m ≥ 2. As mentioned earlier, in China, the current mainstream electric vehicle voltage level is 400V, while some high-end brand vehicles have begun to reach 800V. On the other hand, most charging infrastructure before 2017 was 500V, and newer charging infrastructure afterward is mainly 750V, with a smaller proportion of new fast-charging infrastructure at 950V / 1000V. Therefore, the rated voltage of each high-voltage battery can be 400V, which is equal to the minimum voltage level of the electric vehicle. In this embodiment, the rated voltage of both the first high-voltage battery 110 and the second high-voltage battery 120 is 400V.

[0029] The high-voltage battery system for a vehicle according to this disclosure may further include a switching unit 200, which is capable of connecting the at least two high-voltage batteries in parallel or in series.

[0030] The switching battery 200 may include 2×(n-1) parallel switches and n-1 series switches, where n equals the number of high-voltage batteries. In this configuration, one parallel switch is connected to the positive output terminal of one high-voltage battery on one side and to the positive output terminal of the next high-voltage battery on the other side; another parallel switch is connected to the negative output terminal of one high-voltage battery on one side and to the negative output terminal of the next high-voltage battery on the other side; and a series switch is connected to the negative output terminal of one high-voltage battery on one side and to the positive output terminal of the next high-voltage battery on the other side. When the parallel switches are closed and the series switches are open, the high-voltage batteries are connected in parallel; when the parallel switches are open and the series switches are closed, the high-voltage batteries are connected in series.

[0031] In this embodiment, switch 210 is connected to the positive output terminal of the first high-voltage battery 110 on the first side and to the positive output terminal of the second high-voltage battery 120 on the second side. Switch 220 is connected to the negative output terminal of the first high-voltage battery 110 on the first side and to the negative output terminal of the second high-voltage battery 120 on the second side. Switch 230 is connected to the negative output terminal of the first high-voltage battery 110 on the first side and to the positive output terminal of the second high-voltage battery 120 on the second side. When switches 210 and 220 are closed and switch 230 is open, the first and second high-voltage batteries 110 and 120 are connected in parallel. When switches 210 and 220 are open and switch 230 is closed, the first and second high-voltage batteries 110 and 120 are connected in series.

[0032] The switch can be a relay, a power semiconductor switch, etc. Furthermore, the series switch and the parallel switch can have an interlocking function. That is, when the series switch is closed, the parallel switch is prohibited from closing, and vice versa. In other words, the series switch and the parallel switch cannot be closed simultaneously. In this embodiment, switches 210 and 220 cannot be closed simultaneously with switch 230.

[0033] The high-voltage battery system for a vehicle according to this disclosure may also include a controller 300. The controller 300 may be part of a battery management system (BMS), part of a vehicle control center, or a separate control device.

[0034] When the vehicle is neither charging nor being driven, the controller 300 can be configured to disconnect all switches of the switching unit 200. In this embodiment, as... Figure 1 As shown, controller 300 disconnects all switches 210, 220, and 230.

[0035] When the high-voltage battery system is used to supply voltage to the vehicle's drive unit, the controller 300 can be configured to connect the at least two high-voltage batteries in parallel or in series based on the vehicle's rated drive voltage. In this embodiment, if the vehicle's rated drive voltage is 400V, the controller 300 connects the first and second high-voltage batteries 110 and 120 in parallel. If the vehicle's rated drive voltage is 800V, the controller 300 connects the first and second high-voltage batteries 110 and 120 in series.

[0036] When the vehicle is connected to an external charging device to charge the at least two high-voltage batteries, the controller 300 can be configured to: first connect the at least two high-voltage batteries 110, 120 in series, and then set the electrical connection state of the at least two high-voltage batteries 110, 120 according to the relationship between the output voltage of the external charging device and the series voltage of the at least two high-voltage batteries 110, 120, until the state of charge (Soc) of the at least two high-voltage batteries 110, 120 reaches 100%.

[0037] Specifically, if the output voltage of the external charging device is greater than the series voltage of the at least two high-voltage batteries 110 and 120, then the series electrical connection of the at least two high-voltage batteries 110 and 120 is maintained (e.g., Figure 2 (As shown), until the state of charge (Soc) of the at least two high-voltage batteries reaches 100%. If the output voltage of the external charging device is less than or equal to the series voltage of the at least two high-voltage batteries 110 and 120, then after a preset condition is met, the at least two high-voltage batteries are connected in parallel (e.g., Figure 3 (As shown), until the state of charge (Soc) of the at least two high-voltage batteries 110 and 120 reaches 100%. The preset condition may be that the state of charge of the at least two high-voltage batteries 110 and 120 remains constant for a period of time. Alternatively or additionally, the preset condition may be: if the output voltage of the external charging device is close to p times the rated voltage of the high-voltage battery, where p ≥ 1, then the state of charge of the at least two high-voltage batteries reaches 40p%. Alternatively or additionally, the preset condition may be: the charged voltage of the at least two high-voltage batteries 110 and 120 is more than 90% of the output voltage of the external charging device.

[0038] Within the scope of this disclosure, the external charging device can be a fast, high-voltage charging station, charging pile, or charging pole. The output voltage of the external charging device is set, in particular, according to national or local regulations.

[0039] Furthermore, as can be seen from the attached diagram, each high-voltage battery 110, 120 can also be equipped with a protection device, such as fuses 410, 420. This can improve the safety of the high-voltage battery system.

[0040] Furthermore, the high-voltage battery system may also include a pre-charge unit. This prevents excessive surge current from the higher-voltage battery causing a voltage difference between the individual high-voltage batteries 110 and 120. Therefore, the safety of the high-voltage battery system can also be improved.

[0041] Figure 4A flowchart illustrating a control method for a high-voltage battery system for a vehicle according to an exemplary embodiment of the present disclosure is shown.

[0042] like Figure 4 As shown, the method begins in step S10.

[0043] In step S20, the vehicle is connected to an external charging device.

[0044] In step S30, it is determined whether the high-voltage battery system for the vehicle needs to be charged. If charging is not required, the process ends at step S90. If charging is required, the process ends at step S40.

[0045] In step S40, at least two high-voltage batteries 110 and 120 are connected in series.

[0046] In step S50, it is determined whether the output voltage of the external charging device is greater than the series voltage of at least two high-voltage batteries 110 and 120.

[0047] If the output voltage of the external charging device is greater than the series voltage of at least two high-voltage batteries 110 and 120, then step S60 is reached. In step S60, the at least two high-voltage batteries 110 and 120 are kept in series until the state of charge (Soc) of the at least two high-voltage batteries 110 and 120 reaches 100%. Then, step S90 is reached to end the process.

[0048] If the output voltage of the external charging device is less than or equal to the series voltage of at least two high-voltage batteries 110 and 120, then step S70 is reached.

[0049] In step S70, it is determined whether a preset condition is met. In an advantageous embodiment, it is determined whether the state of charge (Soc) of the at least two high-voltage batteries 110 and 120 remains constant for a period of time, for example, about 60 seconds. Alternatively or additionally, in an advantageous embodiment, if the output voltage of the external charging device is close to p times the rated voltage of the high-voltage batteries 110 and 120, where p ≥ 1, it is determined whether the state of charge of the at least two high-voltage batteries 110 and 120 reaches 40p%. For example, if the output voltage of the external charging device is 500V, which is close to 1 times the rated voltage of the high-voltage batteries, it is determined whether the state of charge of the at least two high-voltage batteries 110 and 120 reaches 40%. If the output voltage of the external charging device is 750V, which is close to 2 times the rated voltage of the high-voltage batteries, it is determined whether the state of charge of the at least two high-voltage batteries 110 and 120 reaches 80%. Alternatively or additionally, in an advantageous embodiment, it is determined whether the charged voltage of the at least two high-voltage batteries 110, 120 is more than 90% of the output voltage of the external charging device. For example, if the output voltage of the external charging device is 500V, it is determined whether the charged voltage of the at least two high-voltage batteries 110, 120 is more than 450V. If the output voltage of the external charging device is 750V, it is determined whether the charged voltage of the at least two high-voltage batteries 110, 120 is more than 675V.

[0050] After at least one of the above-mentioned preset conditions is met, step S80 is reached. In step S80, the at least two high-voltage batteries 110 and 120 are connected in parallel until the state of charge of the at least two high-voltage batteries 110 and 120 reaches 100%. Then, step S90 is reached to end the process.

[0051] Therefore, when using an external charging device with an output voltage of 750V to charge a vehicle with a rated drive voltage of 400V, the high-voltage batteries of the vehicle's high-voltage battery system can first be connected in series and charged until the state of charge (SOC) of the high-voltage battery system reaches 80%. Then, the high-voltage batteries of the vehicle's high-voltage battery system can be connected in parallel and charged until the state of charge (SOC) of the high-voltage battery system reaches 100%, that is, fully charged.

[0052] When using an external charging device with an output voltage of 500V to charge a vehicle with a rated drive voltage of 800V, first connect the high-voltage batteries of the vehicle's high-voltage battery system in series and charge each series-connected high-voltage battery until the state of charge (SOC) of the high-voltage battery system reaches 40%. Then, connect the high-voltage batteries of the vehicle's high-voltage battery system in parallel and charge each parallel-connected high-voltage battery until the state of charge (SOC) of the high-voltage battery system reaches 100%, that is, it is fully charged.

[0053] The high-voltage battery system and its control method disclosed herein allow for flexible switching between parallel and series connections depending on the voltage level of the charging infrastructure. Therefore, through this flexible high-voltage battery system design, the vehicle battery voltage level can be flexibly adapted to fast-charging infrastructure, thereby enabling efficient use of the charging source and significantly reducing charging time.

[0054] Within the scope of this disclosure, the expression "and / or" as used herein means to include at least one of the components listed before and after the expression. Furthermore, the expression "connected / linked" as used herein means to include a direct connection to another component or an indirect connection via another component. The singular form herein also includes the plural form, unless specifically stated in the wording. Moreover, the use of "comprises" or "includes" in this document means that at least one other component, step, operation, or element is present or added.

[0055] It should be understood that the term “vehicle” or “of a vehicle” or other similar terms used in this document generally include motor vehicles, such as passenger vehicles including sport utility vehicles (SUVs), buses, trucks, various commercial vehicles, vessels including various boats and ships, aircraft, etc.

[0056] Any method, program, algorithm, or code described herein can be converted into or expressed as a programming language or computer program. "Programming language" and "computer program" are any language used to assign instructions to a computer, and include (but are not limited to) these languages ​​and their derivatives: assembly language, Basic, batch files, BCPL, C, C+, C++, Delphi, Fortran, Java, JavaScript, machine code, operating system command languages, Pascal, Perl, PL1, scripting languages, Visual Basic, their own programmable meta-languages, and first-, second-, third-, fourth-, and fifth-generation computer languages. Databases and other data schemas, and any other meta-languages, are also included. For the purposes of this definition, no distinction is made between languages ​​that are interpreted or compiled, or between languages ​​that use both compilation and interpretation methods. For the purposes of this definition, no distinction is made between compiled and source versions of a program. Therefore, referring to a program in a programming language that can exist in more than one state (such as source state, compiled state, object state, or link state) refers to any and all such states. This definition also includes valid instructions and the intent of these instructions.

[0057] Any method, program, algorithm, or code described herein may be contained on one or more machine-readable media or memories. The term "memory" may include an apparatus that provides (e.g., stores and / or transmits) information in a machine-readable format such as a processor, computer, or digital processing device. For example, memory may include read-only memory (ROM), random access memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, or any other volatile or non-volatile storage devices. Code or instructions contained thereon may be represented by carrier signals, infrared signals, digital signals, and other similar signals.

[0058] The features disclosed in this application are important and can be implemented not only individually but also in any combination for the implementation of embodiments in different design aspects. The invention is not limited to the illustrated embodiments, but includes or extends to all technical equivalents falling within the scope of the appended claims.

Claims

1. A high-voltage battery system for a vehicle, the high-voltage battery system comprising: At least two high-voltage batteries (110, 120) having the same rated voltage, said at least two high-voltage batteries being able to be installed in the vehicle and configured to power the vehicle's drive unit; A switching unit (200) is capable of connecting the at least two high-voltage batteries (110, 120) in parallel or in series. and A controller (300) is configured to, when the vehicle is connected to an external charging device to charge the at least two high-voltage batteries (110, 120), first connect the at least two high-voltage batteries (110, 120) in series, regardless of whether the output voltage of the external charging device is higher or lower than the rated voltage of the high-voltage batteries; and The controller (300) is further configured to: when the vehicle is connected to an external charging device to charge the at least two high-voltage batteries (110, 120), after connecting the at least two high-voltage batteries (110, 120) in series, If the output voltage of the external charging device is greater than the series voltage of the at least two high-voltage batteries (110, 120), the at least two high-voltage batteries (110, 120) remain connected in series until the state of charge of the at least two high-voltage batteries (110, 120) reaches 100%. If the output voltage of the external charging device is less than or equal to the series voltage of the at least two high-voltage batteries (110, 120), then after a preset condition is met, the at least two high-voltage batteries (110, 120) are connected in parallel until the state of charge of the at least two high-voltage batteries (110, 120) reaches 100%. The preset condition includes: if the output voltage of the external charging device is close to p times the rated voltage of the high-voltage batteries (110, 120), where p ≥ 1, then the state of charge of the at least two high-voltage batteries (110, 120) reaches 40p%, and the state of charge of the at least two high-voltage batteries (110, 120) remains unchanged for a period of time.

2. The high-voltage battery system according to claim 1, characterized in that, The preset conditions also include: The charged voltage of the at least two high-voltage batteries (110, 120) is more than 90% of the output voltage of the external charging device.

3. The high-voltage battery system according to claim 1 or 2, characterized in that, The controller (300) is also configured to disconnect all switches of the switching unit when the vehicle is neither charging nor being driven.

4. The high-voltage battery system according to claim 1 or 2, characterized in that, The switching unit (200) includes 2 × (n-1) parallel switches and n-1 series switches, where n is equal to the number of high-voltage batteries. One parallel switch is connected to the positive output terminal of one high-voltage battery on the first side and to the positive output terminal of the next high-voltage battery on the second side. Another parallel switch is connected to the negative output terminal of one high-voltage battery on the first side and to the negative output terminal of the next high-voltage battery on the second side. A series switch is connected to the negative output terminal of one high-voltage battery on the first side and to the positive output terminal of the next high-voltage battery on the second side.

5. The high-voltage battery system according to claim 4, characterized in that, The controller (300) is also configured to: prohibit the closing of the parallel switch when the series switch is closed, and prohibit the closing of the series switch when the parallel switch is closed.

6. The high-voltage battery system according to claim 1 or 2, characterized in that, The high-voltage battery system also includes a pre-charge unit.

7. A method for controlling a high-voltage battery system for a vehicle, comprising the following steps: Determine whether at least two high-voltage batteries (110, 120) of the high-voltage battery system need to be charged; When it is necessary to charge the at least two high-voltage batteries, regardless of whether the output voltage of the external charging device is higher or lower than the rated voltage of the high-voltage batteries, the at least two high-voltage batteries (110, 120) are first connected in series. If the output voltage of the external charging device is greater than the series voltage of the at least two high-voltage batteries (110, 120), the at least two high-voltage batteries (110, 120) are kept in series until the state of charge of the at least two high-voltage batteries (110, 120) reaches 100%. If the output voltage of the external charging device is less than or equal to the series voltage of the at least two high-voltage batteries (110, 120), then after a preset condition is met, the at least two high-voltage batteries (110, 120) are connected in parallel until the state of charge of the at least two high-voltage batteries (110, 120) reaches 100%. The preset condition includes: if the output voltage of the external charging device is close to p times the rated voltage of the high-voltage batteries (110, 120), where p ≥ 1, then the state of charge of the at least two high-voltage batteries (110, 120) reaches 40p%, and the state of charge of the at least two high-voltage batteries (110, 120) remains unchanged for a period of time.

8. The method according to claim 7, characterized in that, The preset conditions also include: The charged voltage of the at least two high-voltage batteries (110, 120) is more than 90% of the output voltage of the external charging device.

9. A vehicle having a high-voltage battery system according to any one of claims 1 to 6 and / or configured to perform the method according to any one of claims 7 to 8.

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