Charging method and charging system for power battery of electric vehicle and electric vehicle

Abstract

The invention provides a charging method and a charging system for a power battery of an electric vehicle and the electric vehicle, and belongs to the field of electric vehicles. The charging method for the power battery of the electric vehicle comprises the steps that when the voltage of a first charging port of the electric vehicle is lower than that of the power battery, a first battery pack of the power battery and the first charging port are controlled to form a first charging loop, and a second battery pack of the power battery and the first charging port are controlled to form a second charging loop, the power battery at least comprises a first battery pack and a second battery pack. According to the invention, the first battery pack and the second battery pack are respectively connected with the first charging port to form the first charging loop and the second charging loop which are charged in parallel, so that the charging voltage input by the power battery is increased.

Description

Technical Field

[0001] The present invention relates to the field of electric vehicles, and in particular to a charging method for an electric vehicle power battery, an electric vehicle charging system and an electric vehicle. Background Art

[0002] With the rapid development of electric vehicles in the automotive industry, users are paying more and more attention to the charging speed and driving range of electric vehicles. The charging system that uses a high-voltage battery of more than 500V and a dual-gun charging system is an effective solution to improve the charging speed and driving range of electric vehicles. At present, the DC charging piles in the domestic market are mainly divided into low-voltage charging piles of 500V and below and high-voltage charging piles of more than 500V. Therefore, the charging system of electric vehicles using high-voltage batteries needs to be compatible with DC charging piles with different output voltage ranges to meet market and user needs.

[0003] In order to be compatible with low-voltage DC charging piles below 500V, the existing electric vehicle dual-gun charging system usually adopts a charging solution in which the first charging port is used to boost the voltage to charge the high-voltage power battery, and the second charging port is separately connected to the high-voltage power battery for charging.

[0004] However, in the prior art, when the second charging port is connected to a low-voltage DC charging column alone, the high-voltage power battery pack cannot be charged; when the first charging port and the second charging port are charged at the same time, because the second charging port is connected to a low-voltage DC charging column, it is impossible to charge the high-voltage power battery pack with two guns. Summary of the invention

[0005] In order to solve the above-mentioned technical defects, the present invention provides a charging method and a charging system for an electric vehicle power battery, and an electric vehicle. The charging method for an electric vehicle power battery provided by the present invention is used to control the first charging port to charge the first battery pack and the second battery pack respectively when the voltage of the first charging port of the electric vehicle is lower than the voltage of the power battery, so as to form a first charging circuit and a second charging circuit for parallel charging, so as to increase the charging voltage input to the power battery.

[0006] A first aspect of the present invention provides a method for charging a power battery of an electric vehicle, the method comprising:

[0007] When the voltage of the first charging port of the electric vehicle is lower than the voltage of the power battery, the first battery pack of the power battery is controlled to form a first charging circuit with the first charging port, and the second battery pack of the power battery is controlled to form a second charging circuit with the first charging port, and the power battery includes at least a first battery pack and a second battery pack.

[0008] In an embodiment of the present invention, the method further includes:

[0009] When the voltage of the first charging port is higher than the voltage of the power battery, the power battery and the first charging port are controlled to form a charging loop.

[0010] In an embodiment of the present invention, the method further includes:

[0011] When the capacity of the first battery pack is less than the capacity of the second battery pack, controlling the first battery pack and the first charging port to form a balanced charging loop;

[0012] When the capacity of the second battery pack is smaller than the capacity of the first battery pack, the second battery pack and the first charging port are controlled to form a balanced charging loop.

[0013] A second aspect of the present invention provides a method for charging a power battery of an electric vehicle, the method comprising:

[0014] When the voltage of the first charging port of the electric vehicle is lower than the voltage of the power battery, the first battery pack of the power battery and the first charging port are controlled to form a first charging circuit, and the second battery pack of the power battery and the first charging port are controlled to form a second charging circuit.

[0015] When the voltage of the second charging port of the electric vehicle is lower than the voltage of the power battery, the first battery pack and the second charging port are controlled to form a third charging circuit, and the second battery pack and the second charging port are controlled to form a fourth charging circuit, and the power battery includes at least the first battery pack and the second battery pack.

[0016] In an embodiment of the present invention, the method further includes:

[0017] When the voltage of the first charging port is higher than the voltage of the power battery, the power battery and the first charging port are controlled to form a charging circuit.

[0018] When the voltage of the second charging port is higher than the voltage of the power battery, the power battery and the second charging port are controlled to form a charging loop.

[0019] In an embodiment of the present invention, the method further includes:

[0020] When the capacity of the first battery pack is less than the capacity of the second battery pack, controlling the first battery pack and the first charging port to form a balanced charging loop, and the first battery pack and the second charging port to form a balanced charging loop;

[0021] When the capacity of the second battery pack is smaller than that of the first battery pack, the second battery pack and the first charging port are controlled to form a balanced charging loop, and the second battery pack and the second charging port are controlled to form a balanced charging loop.

[0022] A third aspect of the present invention provides an electric vehicle charging system, comprising:

[0023] a first charging port; and

[0024] A control unit, wherein the control unit is used to control a first battery pack of the power battery and the first charging port to form a first charging circuit, and to control a second battery pack of the power battery and the first charging port to form a second charging circuit when the voltage of the first charging port is lower than the voltage of the power battery of the electric vehicle, wherein the power battery comprises at least a first battery pack and a second battery pack.

[0025] In an embodiment of the present invention, the control unit is further configured to control the power battery and the first charging port to form a charging loop when the voltage of the first charging port is higher than the voltage of the power battery.

[0026] A fourth aspect of the present invention provides an electric vehicle charging system, comprising:

[0027] First charging port;

[0028] A second charging port; and

[0029] A control unit, the control unit is used to control the first battery pack of the power battery and the first charging port to form a first charging circuit, control the second battery pack of the power battery and the first charging port to form a second charging circuit, control the first battery pack of the power battery and the second charging port to form a third charging circuit, and control the second battery pack of the power battery and the second charging port to form a fourth charging circuit when the voltage of the first charging port or the voltage of the second charging port is lower than the voltage of the power battery of the electric vehicle, the power battery comprising at least the first battery pack and the second battery pack.

[0030] In an embodiment of the present invention, the control unit is further configured to control the power battery to form a charging circuit with the first charging port and the power battery to form a charging circuit with the second charging port when the voltage of the first charging port and the voltage of the second charging port are both higher than the voltage of the power battery.

[0031] In an embodiment of the present invention, the first charging circuit includes a first charging circuit switch, and the control unit is used to control the conduction state of the first charging circuit by controlling the opening and closing of the first charging circuit switch;

[0032] The second charging circuit includes a second charging circuit switch, and the control unit is used to control the conduction state of the second charging circuit by controlling the opening and closing of the second charging circuit switch;

[0033] The third charging circuit includes a third charging circuit switch, and the control unit is used to control the conduction state of the third charging circuit by controlling the opening and closing of the third charging circuit switch;

[0034] The fourth charging circuit includes a fourth charging circuit switch, and the control unit is used to control the conduction state of the fourth charging circuit by controlling the opening and closing of the fourth charging circuit switch.

[0035] In an embodiment of the present invention, the first charging circuit switch is a three-phase inverter bridge.

[0036] In the embodiment of the present invention, the third charging circuit switch and the first charging circuit switch are the same switch, and the fourth charging circuit switch and the second charging circuit switch are the same switch.

[0037] A fifth aspect of the present invention further provides an electric vehicle charging system, comprising:

[0038] First charging port;

[0039] A second charging port; and

[0040] A control unit, the control unit is used to control the first battery pack of the power battery and the first charging port to form a first charging circuit, control the second battery pack of the power battery and the first charging port to form a second charging circuit, control the first battery pack of the power battery and the second charging port to form a third charging circuit, and control the second battery pack of the power battery and the second charging port to form a fourth charging circuit when the voltage of the first charging port is lower than the voltage of the power battery of the electric vehicle and the voltage of the second charging port is higher than the voltage of the power battery of the electric vehicle, the power battery comprises at least a first battery pack and a second battery pack.

[0041] A sixth aspect of the present invention provides an electric vehicle, comprising the electric vehicle charging system as described above.

[0042] In an embodiment of the present invention, the electric vehicle further includes a power battery, and the power battery includes at least a first battery pack and a second battery pack, and the first battery pack and the second battery pack are connected in series via a first switch.

[0043] The power battery of the present invention comprises at least a first battery pack and a second battery pack. When the voltage of the first charging port of the electric vehicle is lower than the voltage of the power battery, the first battery pack of the power battery is controlled to form a first charging circuit with the first charging port, and the second battery pack of the power battery is controlled to form a second charging circuit with the first charging port, thereby overcoming the problem that the high-voltage power battery pack cannot be charged when the charging port is connected alone to a low-voltage DC charging column.

[0044] Other features and advantages of the technical solution of the present invention will be described in detail in the specific implementation section below. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0046] Figure 1is a flow chart of a charging method for an electric vehicle power battery provided in Example 1 of the present invention;

[0047] Figure 2 is a structural block diagram of an electric vehicle charging system provided by Embodiment 1 of the present invention;

[0048] Figure 3 This is a charging principle diagram in which the voltage of the electric vehicle charging port provided by Embodiment 1 of the present invention is lower than the voltage of the power battery charging port;

[0049] Figure 4 This is a charging principle diagram in which the voltage of the electric vehicle charging port provided by Embodiment 1 of the present invention is higher than the voltage of the power battery charging port;

[0050] Figure 5 is a charging principle diagram when the capacity of the first battery pack is uneven provided in Example 1 of the present invention;

[0051] Figure 6 is a charging principle diagram when the capacity of the second battery pack provided by Embodiment 1 of the present invention is unbalanced;

[0052] Figure 7 is a flow chart of a charging method for an electric vehicle power battery provided in Embodiment 2 of the present invention;

[0053] Figure 8 is a structural block diagram of an electric vehicle charging system provided by Embodiment 2 of the present invention;

[0054] Fig. 9 This is a charging principle diagram in which the voltage of the electric vehicle charging port provided by Embodiment 2 of the present invention is lower than the voltage of the power battery charging port;

[0055] Fig.10 This is a charging principle diagram in which the voltage of the electric vehicle charging port provided by Embodiment 2 of the present invention is higher than the voltage of the power battery charging port;

[0056] Fig.11 is a charging principle diagram when the capacity of the first battery pack is uneven provided in Embodiment 2 of the present invention;

[0057] Fig.12 is a charging principle diagram when the capacity of the second battery pack is uneven provided by Embodiment 2 of the present invention;

[0058] Fig.13 is a structural block diagram of an electric vehicle charging system provided by Embodiment 3 of the present invention;

[0059] Fig.14 This is a charging principle diagram in which the voltage of the electric vehicle charging port provided by Embodiment 3 of the present invention is lower than the voltage of the power battery charging port;

[0060] Fig.15This is a charging principle diagram in which the voltage of the electric vehicle charging port provided by Embodiment 3 of the present invention is higher than the voltage of the power battery charging port;

[0061] Fig.16 is a charging principle diagram when the capacity of the first battery pack is uneven provided in Example 3 of the present invention;

[0062] Fig.17 is a charging principle diagram when the capacity of the second battery pack is uneven provided by Embodiment 3 of the present invention;

[0063] Fig.18 This is a structural block diagram of an electric vehicle provided by Example 3 of the present invention.

[0064] Description of Reference Numerals

[0065] 01-first charging port, 02-first battery pack, 03-second battery pack, 04-second charging port, 05-three-phase inverter bridge, K1-first switch, K2-first positive switch, K3-first negative switch, K4-first charging circuit switch, K5 second charging circuit switch, K6-second positive switch, K7-second negative switch. DETAILED DESCRIPTION

[0066] In order to make the technical solutions and advantages of the embodiments of the present invention more clearly understood, the exemplary embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than an exhaustive list of all the embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0067] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0068] In the present invention, unless otherwise clearly specified and limited, the terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or can communicate with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0069] In the process of realizing the present invention, the inventors found that in the prior art, the second charging port of the dual-gun charging system directly connected to the high-voltage power battery cannot charge the high-voltage power battery pack of the dual-gun charging system when connected to a low-voltage DC charging pile.

[0070] In view of the above problems, an embodiment of the present invention provides a charging method for a power battery of an electric vehicle, wherein the power battery comprises at least a first battery pack and a second battery pack, and the method comprises:

[0071] When the voltage of the first charging port of the electric vehicle is lower than the voltage of the power battery, the first battery pack of the power battery and the first charging port are controlled to form a first charging circuit, and the second battery pack of the power battery and the first charging port are controlled to form a second charging circuit.

[0072] The power battery of the present invention comprises at least a first battery pack and a second battery pack. When the voltage of the first charging port of the electric vehicle is lower than the voltage of the power battery, the first battery pack of the power battery is controlled to form a first charging circuit with the first charging port, and the second battery pack of the power battery is controlled to form a second charging circuit with the first charging port. When the voltage of the entire power battery pack is higher than the voltage of the charging port, it is charged through the first charging circuit and the second charging circuit respectively, thereby overcoming the problem that the high-voltage power battery pack cannot be charged when the charging port is connected to a low-voltage DC charging column alone.

[0073] Example 1

[0074] The electric vehicle charging system provided in this embodiment has one charging port, which is the first charging port 01. In this embodiment, the power battery includes a first battery pack 02, a second battery pack 03 and a first switch K1, and the first battery pack 02 and the second battery pack 03 are connected in series through the first switch K1.

[0075] In other embodiments of the present invention, the power battery includes three battery packs, namely, a first battery pack, a second battery pack, and a third battery pack. The first battery pack, the second battery pack, and the third battery pack are all connected in series. The first battery pack and the second battery pack are connected in series through a first switch, and the second battery pack and the third battery pack are connected in series through a second switch. The sum of the voltages of the multiple battery packs of the power battery pack is greater than the voltage of the charging port (i.e., the voltage of the charging pile), and the voltage of a single battery pack in the power battery pack is less than the voltage of the charging port.

[0076] Figure 1 1 is a flow chart of a method for charging a power battery of an electric vehicle provided in Example 1 of the present invention. Figure 1 As shown, this embodiment provides a charging method for an electric vehicle power battery, comprising the following steps:

[0077] Detect the voltage of the first charging port 01;

[0078] Determine whether the voltage of the first charging port 01 is less than the voltage of the power battery;

[0079] If the voltage of the first charging port 01 is lower than the voltage of the power battery, the first switch K1 is controlled to be disconnected to disconnect the first battery pack 02 from the second battery pack 03, so that the first battery pack 02 and the first charging port 01 form a first charging circuit, and the second battery pack 03 and the first charging port 01 form a second charging circuit, and the first charging circuit and the second charging circuit are connected in parallel;

[0080] If the voltage of the first charging port 01 is higher than the voltage of the power battery, the first switch K1 is controlled to close to connect the first battery pack 02 with the second battery pack 03 , so that the first battery pack 02 , the second battery pack 03 and the first charging port 01 form a series charging circuit.

[0081] In this embodiment, the method further includes: detecting the capacity state of the first battery pack 02 and the capacity state of the second battery pack 03; determining whether the capacity of the first battery pack 02 and the capacity of the second battery pack 03 are balanced; when the capacity of the first battery pack 02 is unbalanced, that is, the capacity of the first battery pack 02 is less than the capacity of the second battery pack 03, the first battery pack 02 is disconnected from the second battery pack 03 by controlling the first switch K1 to be disconnected, so that the first battery pack 02 and the first charging port 01 form a balanced charging loop; when the capacity of the second battery pack 03 is unbalanced, that is, the capacity of the second battery pack 03 is less than the capacity of the first battery pack 02, the first battery pack 02 is disconnected from the second battery pack 03 by controlling the first switch K1 to be disconnected, so that the second battery pack 03 and the first charging port 01 form a balanced charging loop. Specifically, the unbalanced capacity of the first battery pack 02 indicates that the first battery pack 02 is not fully charged but the second battery pack 03 is fully charged; the unbalanced capacity of the second battery pack 03 indicates that the second battery pack 03 is not fully charged but the first battery pack 02 is fully charged.

[0082] Figure 2 : is a structural block diagram of an electric vehicle charging system provided by Embodiment 1 of the present invention. Figure 2 As shown, this embodiment provides an electric vehicle charging system, and the electric vehicle charging system includes a control unit and a first charging port 01;

[0083] The control unit is used to control the first battery pack 02 of the electric vehicle to disconnect from the second battery pack 03 when the voltage of the first charging port 01 is lower than the sum of the voltages of the first battery pack 02 and the second battery pack 03 of the electric vehicle, so that the first battery pack 02 and the first charging port 01 form a first charging circuit, the second battery pack 03 and the first charging port 01 form a second charging circuit, and the first charging circuit and the second charging circuit are connected in parallel.

[0084] The control unit is used to control the first battery pack 02 and the second battery pack 03 of the electric vehicle to be connected when the voltage of the first charging port 01 is higher than the sum of the voltages of the first battery pack 02 and the second battery pack 03 of the electric vehicle, so that the first battery pack 02 and the second battery pack 03 form a charging circuit with the first charging port 01.

[0085] Specifically, the power battery includes a first battery pack 02, a second battery pack 03 and a first switch K1. The first battery pack 02 and the second battery pack 03 are connected in series through the first switch K1, and the sum of the voltages of the first battery pack 02 and the second battery pack 03 is the voltage of the power battery; the control unit is used to: when the voltage of the first charging port 01 is higher than the voltage of the power battery, control the first switch K1 to close so that the first battery pack 02 is connected to the second battery pack 03, so that the first battery pack 02, the second battery pack 03 and the first charging port 01 form a series charging circuit; the control unit is used to: when the voltage of the first charging port 01 is lower than the voltage of the power battery, control the first switch K1 to open so that the first battery pack 02 is disconnected from the second battery pack 03, so that the first battery pack 02 and the first charging port 01 form a first charging circuit, the second battery pack 03 and the first charging port 01 form a second charging circuit, and the first charging circuit and the second charging circuit are connected in parallel.

[0086] Specifically, the positive pole of the first charging port 01 is provided with a first positive pole switch K2, the negative pole of the first charging port 01 is provided with a first negative pole switch K3, the first charging circuit is provided with a first charging circuit switch K4, and the second charging circuit is provided with a second charging circuit switch K5.

[0087] Figure 3 The charging principle diagram of the electric vehicle charging port provided by the embodiment 1 of the present invention is lower than the voltage of the power battery charging port; Figure 3 As shown, when the control unit detects that the voltage of the first charging port 01 is lower than the voltage of the power battery, the control unit controls the first switch K1 to be disconnected, and the first positive switch K2, the first negative switch K3, the first charging circuit switch K4, and the second charging circuit switch K5 to be closed, so that the first charging port 01 and the first battery pack 02 form a first charging circuit, the first charging port 01 and the second battery pack 03 form a second charging circuit, and the first charging circuit and the second charging circuit are charged in parallel, so that the DC charging pile with a voltage lower than the power battery can charge the power battery.

[0088] Figure 4 The charging principle diagram of the electric vehicle charging port provided by Embodiment 1 of the present invention is higher than the voltage of the power battery charging port, such as Figure 4As shown, when the control unit detects that the voltage of the first charging port 01 is higher than the voltage of the power battery, the control unit controls the first switch K1, the first positive switch K2 and the first negative switch K3 to close, and the control unit controls the first charging circuit switch K4 and the second charging circuit switch K5 to open, so that the first charging port 01 forms a series charging circuit with the first battery pack 02 and the second battery pack 03, and the first charging port 01 charges the entire electric battery pack.

[0089] In this embodiment, the control unit of the electric vehicle charging system provided by the present invention is also used to detect the capacity status of the first battery pack 02 and the capacity status of the second battery pack 03; the control unit determines whether the capacity of the first battery pack 02 and the capacity of the second battery pack 03 are balanced; when the capacity of the first battery pack 02 is unbalanced, the first switch K1 is controlled to be disconnected, so that the first battery pack 02 and the second battery pack 03 are disconnected, so that the first battery pack 02 and the first charging port 01 form a balanced charging circuit; when the capacity of the second battery pack 03 is unbalanced, the first switch K1 is controlled to be disconnected, so that the first battery pack 02 and the second battery pack 03 are disconnected, so that the second battery pack 03 and the first charging port 01 form a balanced charging circuit.

[0090] Specifically, Figure 5 is a charging principle diagram when the capacity of the first battery pack is uneven provided in Example 1 of the present invention; Figure 5 As shown, when the capacity of the first battery pack 02 is unbalanced, that is, the capacity of the first battery pack 02 is smaller than the capacity of the second battery pack 03, the first charging port 01 charges the first battery pack 02 alone, and the control unit controls the first switch K1 to be disconnected and the second charging circuit switch K5 to be disconnected, and the first positive switch K2, the first negative switch K3 and the first charging circuit switch K4 to be closed, so that the first charging port 01 charges the first battery pack 02 alone.

[0091] Similarly, Figure 6 is a charging principle diagram when the capacity of the second battery pack is uneven provided in Example 1 of the present invention; Figure 6 As shown, when the capacity of the second battery pack 03 is unbalanced, that is, the capacity of the second battery pack 03 is smaller than that of the first battery pack 02, the first charging port 01 charges the second battery pack 03 alone, and the control unit controls the first switch K1 to be disconnected and the first charging circuit switch K4 to be disconnected, and the first positive switch K2, the first negative switch K3 and the second charging circuit switch K5 to be closed, so that the first charging port 01 charges the second battery pack 03 alone to achieve capacity balance between the first battery pack 02 and the second battery pack 03.

[0092] Embodiment 1 of the present invention further provides a charging device, comprising a DC charging pile and the electric vehicle charging system as described above, wherein the DC charging pile is connected to the electric vehicle charging port and is used to charge the power battery through the electric vehicle charging port. The DC charging pile charges the power battery by adopting the charging method for the electric vehicle power battery as described above.

[0093] Embodiment 1 of the present invention further provides an electric vehicle, comprising the electric vehicle charging system as described above.

[0094] Example 2

[0095] The electric vehicle charging system provided in this embodiment has two charging ports, namely a first charging port 01 and a second charging port 04. The power battery includes a first battery pack 02, a second battery pack 03 and a first switch K1. The first battery pack 02 and the second battery pack 03 are connected in series through the first switch K1.

[0096] Figure 7 1 is a flow chart of a method for charging a power battery of an electric vehicle provided in Example 2 of the present invention. Figure 7 As shown, the charging method of the electric vehicle power battery provided in this embodiment includes the following steps:

[0097] Detect the voltage of the first charging port 01 and the second charging port 04 of the electric vehicle;

[0098] Determine whether the voltage of the first charging port 01 or the voltage of the second charging port 04 of the electric vehicle is less than the voltage of the power battery;

[0099] If the voltage of the first charging port 01 or the voltage of the second charging port 04 of the electric vehicle is lower than the voltage of the power battery, the first switch K1 is controlled to be disconnected to disconnect the first battery pack 02 from the second battery pack 03, so that the first battery pack 02 and the first charging port 01 form a first charging circuit, the second battery pack 03 and the first charging port 01 form a second charging circuit, the first battery pack 02 and the second charging port 04 form a third charging circuit, the second battery pack 03 and the second charging port 04 form a fourth charging circuit, the first charging circuit is connected in parallel with the second charging circuit, and the third charging circuit is connected in parallel with the fourth charging circuit;

[0100] If the voltage of the first charging port 01 and the voltage of the second charging port 04 of the electric vehicle are higher than the voltage of the power battery, the first switch K1 is controlled to close to connect the first battery pack 02 and the second battery pack 03, so that the first battery pack 02 and the second battery pack 03 form a series charging circuit with the first charging port 01, and the first battery pack 02 and the second battery pack 03 form a series charging circuit with the second charging port 04.

[0101] In the present embodiment, the method further includes: detecting the capacity status of the first battery pack 02 and the capacity status of the second battery pack 03; judging whether the capacity of the first battery pack 02 and the capacity of the second battery pack 03 are balanced; when the capacity of the first battery pack 02 is unbalanced, that is, the capacity of the first battery pack 02 is less than the capacity of the second battery pack 03, the first battery pack 02 is disconnected from the second battery pack 03 by controlling the first switch K1 to be disconnected, so that the first battery pack 02 and the first charging port 01 form a balanced charging circuit, and the first battery pack 02 and the second charging port 04 form a balanced charging circuit; when the capacity of the second battery pack 03 is unbalanced, that is, the capacity of the second battery pack 03 is less than the capacity of the first battery pack 02, the first battery pack 02 is disconnected from the second battery pack 03 by controlling the first switch K1 to be disconnected, so that the second battery pack 03 and the first charging port 01 form a balanced charging circuit, and the second battery pack 03 and the second charging port 04 form a balanced charging circuit. Specifically, the unbalanced capacity of the first battery pack 02 indicates that the first battery pack 02 is not fully charged but the second battery pack 03 is fully charged; the unbalanced capacity of the second battery pack 03 indicates that the second battery pack 03 is not fully charged but the first battery pack 02 is fully charged.

[0102] Figure 8 : is a structural block diagram of an electric vehicle charging system provided by Embodiment 2 of the present invention. Figure 8 As shown, the electric vehicle charging system provided in this embodiment includes a control unit, a first charging port 01 and a second charging port 04;

[0103] The control unit is used to control the first battery pack 02 of the electric vehicle to disconnect from the second battery pack 03 when the voltage at the first charging port 01 or the voltage at the second charging port 04 is lower than the sum of the voltages of the first battery pack 02 and the second battery pack 03 of the electric vehicle, so that the first battery pack 02 and the first charging port 01 form a first charging circuit, the second battery pack 03 and the first charging port 01 form a second charging circuit, the first battery pack 02 and the second charging port 04 form a third charging circuit, the second battery pack 02 and the second charging port 04 form a fourth charging circuit, the first charging circuit is connected in parallel with the second charging circuit, and the third charging circuit is connected in parallel with the fourth charging circuit.

[0104] When the voltage of the first charging port 01 and the voltage of the second charging port 04 are both higher than the sum of the voltages of the first battery pack 02 and the second battery pack 03 of the electric vehicle, the first battery pack 02 and the second battery pack 03 of the electric vehicle are controlled to be connected so that the first battery pack 02 and the second battery pack 03 form a charging circuit with the first charging port 01, and the first battery pack 02 and the second battery pack 03 form a charging circuit with the second charging port 04.

[0105] Specifically, the power battery includes a first battery pack 02, a second battery pack 03 and a first switch K1. The first battery pack 02 and the second battery pack 03 are connected in series through the first switch K1. The sum of the voltages of the first battery pack 02 and the second battery pack 03 is the voltage of the power battery. The electric vehicle charging port includes a first charging port 01 and a second charging port 04. The control unit is used to: when the voltage of the first charging port 01 and the voltage of the second charging port 04 are both higher than the voltage of the power battery, the first battery pack 02 is connected to the second battery pack 03 by controlling the first switch K1 to close, so that the first battery pack 02 and the second battery pack 03 form a series charging circuit with the first charging port 01, and The first battery pack 02 and the second battery pack 03 form a series charging circuit with the second charging port 04; when the voltage at the first charging port 01 or the voltage at the second charging port 04 is lower than the voltage of the power battery, the first battery pack 02 is disconnected from the second battery pack 03 by controlling the first switch K1 to disconnect, so that the first battery pack 02 and the first charging port 01 form a first charging circuit, the second battery pack 03 and the first charging port 01 form a second charging circuit, the first battery pack 02 and the second charging port 04 form a third charging circuit, the second battery pack 03 and the second charging port 04 form a fourth charging circuit, the first charging circuit is connected in parallel with the second charging circuit, and the third charging circuit is connected in parallel with the fourth charging circuit.

[0106] Specifically, the positive pole of the first charging port 01 is provided with a first positive pole switch K2, the negative pole of the first charging port 01 is provided with a first negative pole switch K3, the positive pole of the second charging port 04 is provided with a second positive pole switch K6, the negative pole of the second charging port 04 is provided with a second negative pole switch K7, the first charging circuit is provided with a first charging circuit switch K4, the second charging circuit is provided with a second charging circuit switch K5, the third charging circuit is provided with a third charging circuit switch, and the fourth charging circuit is provided with a fourth charging circuit switch.

[0107] Fig. 9 The charging principle diagram of the electric vehicle charging port provided by the second embodiment of the present invention is lower than the voltage of the power battery charging port, such as Fig. 9As shown, when the control unit detects that the voltage of the first charging port 01 or the voltage of the second charging port 04 is lower than the voltage of the power battery, the control unit controls the first switch K1 to be disconnected, and the first positive switch K2, the first negative switch K3, the second positive switch K6, the second negative switch K7, the first charging circuit switch K4, the second charging circuit switch K5, the third charging circuit switch and the fourth charging circuit switch to be closed, so that the first charging port 01 and the first battery pack 02 form a first charging circuit, the first charging port 01 and the second battery pack 03 form a second charging circuit, and the first charging circuit and the second charging circuit are charged in parallel, the second charging port 04 and the first battery pack 02 form a third charging circuit, the second charging port 04 and the second battery pack 03 form a fourth charging circuit, and the second charging circuit and the fourth charging circuit are connected in parallel, so that the DC charging pile with a voltage lower than the power battery charges the power battery.

[0108] Fig.10 The charging principle diagram of the electric vehicle charging port provided by the second embodiment of the present invention is higher than the voltage of the power battery charging port, such as Fig.10 As shown, when the control unit detects that the voltage of the first charging port 01 and the voltage of the second charging port 04 are both higher than the voltage of the power battery, the control unit controls the first switch K1, the first positive switch K2, the first negative switch K3, the second positive switch K6 and the second negative switch K7 to close, and the control unit controls the first charging circuit switch K4, the second charging circuit switch K5, the third charging circuit switch and the fourth charging circuit switch to open, so that the first charging port 01 forms a series charging circuit with the first battery pack 02 and the second battery pack 03, and the second charging port 04 forms a series charging circuit with the first battery pack 02 and the second battery pack 03, and the first charging port 01 and the second charging port 04 charge the entire electric battery pack.

[0109] In this embodiment, the control unit of the electric vehicle charging system provided by the present invention is also used to detect the capacity status of the first battery pack 02 and the capacity status of the second battery pack 03; the control unit determines whether the capacity of the first battery pack 02 and the capacity of the second battery pack 03 are balanced; when the capacity of the first battery pack 02 is unbalanced, the first switch K1 is controlled to be disconnected to disconnect the first battery pack 02 and the second battery pack 03, so that the first battery pack 02 and the first charging port 01 form a balanced charging circuit and the first battery pack 02 and the second charging port 04 form a balanced charging circuit; when the capacity of the second battery pack 03 is unbalanced, the first switch K1 is controlled to be disconnected to disconnect the first battery pack 02 and the second battery pack 03, so that the second battery pack 03 and the first charging port 01 form a balanced charging circuit and the second battery pack 03 and the second charging port 04 form a balanced charging circuit.

[0110] Specifically, Fig.11is a charging principle diagram when the capacity of the first battery pack is unbalanced provided in Example 2 of the present invention, such as Fig.11 As shown, when the capacity of the first battery pack 02 is unbalanced, that is, the capacity of the first battery pack 02 is smaller than the capacity of the second battery pack 03, the first charging port 01 and the second charging port 04 charge the first battery pack 02 separately, and the control unit controls the first switch K1 to be disconnected, the second charging circuit switch K5 to be disconnected, and the fourth charging circuit switch to be disconnected, and the first positive switch K2, the first negative switch K3, the second positive switch K6, the second negative switch K7, the third charging circuit switch and the first charging circuit switch K4 are closed, so that the first charging port 01 and the second charging port 04 charge the first battery pack 02 separately.

[0111] Similarly, Fig.12 is a charging principle diagram when the capacity of the second battery pack is unbalanced provided by Embodiment 2 of the present invention, such as Fig.12 As shown, when the capacity of the second battery pack 03 is unbalanced, that is, the capacity of the second battery pack 03 is smaller than that of the first battery pack 02, the first charging port 01 and the second charging port 04 charge the second battery pack 03 separately, and the control unit controls the first switch K1 to be disconnected, the first charging circuit switch K4 to be disconnected, and the third charging circuit switch to be disconnected, and the first positive switch K2, the first negative switch K3, the second positive switch K6, the second negative switch K7, the fourth charging circuit switch and the second charging circuit switch K5 to be closed, so that the first charging port 01 and the second charging port 04 charge the second battery pack 03 separately, so as to achieve capacity balance between the first battery pack 02 and the second battery pack 03.

[0112] Furthermore, in this embodiment, the first charging circuit switch K4 and the third charging circuit switch are the same switch, and the second charging circuit switch K5 and the fourth charging circuit switch are the same switch. Reducing the number of switches connected can save costs and reduce losses.

[0113] Embodiment 2 of the present invention further provides a charging device, comprising a DC charging pile and the electric vehicle charging system as described above, wherein the DC charging pile is connected to the electric vehicle charging port and is used to charge the power battery through the electric vehicle charging port. The DC charging pile charges the power battery by adopting the charging method for the electric vehicle power battery as described above.

[0114] Embodiment 2 of the present invention further provides an electric vehicle, comprising the electric vehicle charging system as described above.

[0115] Example 3

[0116] Fig.13 A structural block diagram of an electric vehicle charging system provided in Embodiment 3 of the present invention is shown in FIG. Fig.13As shown, an embodiment of the present invention provides an electric vehicle charging system, the electric vehicle charging system has two charging ports, namely a first charging port 01 and a second charging port 04, and the electric vehicle charging system also includes a control unit;

[0117] The control unit is used to control the first battery pack 02 of the electric vehicle to disconnect from the second battery pack 03 when the voltage at the first charging port 01 or the voltage at the second charging port 04 is lower than the sum of the voltages of the first battery pack 02 and the second battery pack 03 of the electric vehicle, so that the first battery pack 02 and the first charging port 01 form a first charging circuit, the second battery pack 03 and the first charging port 01 form a second charging circuit, the first battery pack 02 and the second charging port 04 form a third charging circuit, the second battery pack 02 and the second charging port 04 form a fourth charging circuit, the first charging circuit is connected in parallel with the second charging circuit, and the third charging circuit is connected in parallel with the fourth charging circuit.

[0118] When the voltage of the first charging port 01 and the voltage of the second charging port 04 are both higher than the sum of the voltages of the first battery pack 02 and the second battery pack 03 of the electric vehicle, the first battery pack 02 and the second battery pack 03 of the electric vehicle are controlled to be connected so that the first battery pack 02 and the second battery pack 03 form a charging circuit with the first charging port 01, and the first battery pack 02 and the second battery pack 03 form a charging circuit with the second charging port 04.

[0119] Specifically, the power battery includes a first battery pack 02, a second battery pack 03 and a first switch K1. The first battery pack 02 and the second battery pack 03 are connected in series through the first switch K1. The sum of the voltages of the first battery pack 02 and the second battery pack 03 is the voltage of the power battery. The control unit is used to: when the voltage of the first charging port 01 and the voltage of the second charging port 04 are both higher than the voltage of the power battery, the first battery pack 02 and the second battery pack 03 are connected by controlling the first switch K1 to close, so that the first battery pack 02 and the second battery pack 03 form a series charging circuit with the first charging port 01, and the first battery pack 02 and the second battery pack 03 are connected. A series charging circuit is formed with the second charging port 04; when the voltage at the first charging port 01 or the voltage at the second charging port 04 is lower than the voltage of the power battery, the first battery pack 02 is disconnected from the second battery pack 03 by controlling the first switch K1 to disconnect, so that the first battery pack 02 and the first charging port 01 form a first charging circuit, the second battery pack 03 and the first charging port 01 form a second charging circuit, the first battery pack 02 and the second charging port 04 form a third charging circuit, the second battery pack 03 and the second charging port 04 form a fourth charging circuit, the first charging circuit is connected in parallel with the second charging circuit, and the third charging circuit is connected in parallel with the fourth charging circuit.

[0120] Specifically, the positive pole of the first charging port 01 is provided with a first positive pole switch K2, the negative pole of the first charging port 01 is provided with a first negative pole switch K3, the positive pole of the second charging port 04 is provided with a second positive pole switch K6, the negative pole of the second charging port 04 is provided with a second negative pole switch K7, the first charging circuit is provided with a first charging circuit switch K4, the second charging circuit is provided with a second charging circuit switch K5, the third charging circuit is provided with a third charging circuit switch, and the fourth charging circuit is provided with a fourth charging circuit switch.

[0121] Fig.14 The charging principle diagram of the electric vehicle charging port provided by the third embodiment of the present invention is lower than the voltage of the power battery charging port. Fig.14 As shown, the first charging circuit switch K4 and the third charging circuit switch are the same switch, which is a three-phase inverter bridge. When the first charging circuit switch K4 is closed, the switch tubes VT2 / VT4 / VT6 of the three-phase inverter bridge are turned on. When the first charging circuit switch K4 is opened, the three-phase inverter bridge is in other conduction states except the conduction state of the switch tubes VT2 / VT4 / VT6.

[0122] In this embodiment, when the control unit detects that the voltage of the first charging port 01 or the voltage of the second charging port 04 is lower than the voltage of the power battery, the control unit controls the first switch K1 to be disconnected, the first positive switch K2, the first negative switch K3, the second positive switch K6, the second negative switch K7, the second charging circuit switch K5 and the fourth charging circuit switch to be closed, and the control unit controls the switch tubes VT2 / VT4 / VT6 of the three-phase inverter bridge to be turned on, so that the first charging port 01 and the first battery pack 02 form a first charging circuit, the first charging port 01 and the second battery pack 03 form a second charging circuit, and the first charging circuit and the second charging circuit are charged in parallel, the second charging port 04 and the first battery pack 02 form a third charging circuit, the second charging port 04 and the second battery pack 03 form a fourth charging circuit, and the second charging circuit and the fourth charging circuit are connected in parallel, so that the DC charging pile with a voltage lower than the power battery charges the power battery.

[0123] Fig.15 The charging principle diagram of the electric vehicle charging port provided by the third embodiment of the present invention is higher than the voltage of the power battery charging port. Fig.15As shown, when the control unit detects that the voltage of the first charging port 01 and the voltage of the second charging port 04 are both higher than the voltage of the power battery, the control unit controls the first switch K1, the first positive switch K2, the first negative switch K3, the second positive switch K6 and the second negative switch K7 to be closed, and the control unit controls the three-phase inverter bridge to be in other conduction states except the conduction state of the switch tubes VT2 / VT4 / VT6. The control unit is also used to control the second charging circuit switch K5 and the fourth charging circuit switch to be disconnected, so that the first charging port 01 forms a series charging circuit with the first battery pack 02 and the second battery pack 03, and the second charging port 04 forms a series charging circuit with the first battery pack 02 and the second battery pack 03. The first charging port 01 and the second charging port 04 charge the entire electric battery pack.

[0124] Fig.16 is a charging principle diagram when the capacity of the first battery pack is uneven provided in Example 3 of the present invention, such as Fig.16 As shown, when the capacity of the first battery pack 02 is unbalanced, that is, the capacity of the first battery pack 02 is smaller than the capacity of the second battery pack 03, the first charging port 01 and the second charging port 04 charge the first battery pack 02 separately, the control unit controls the first switch K1 to be disconnected, the second charging circuit switch K5 to be disconnected, and the fourth charging circuit switch to be disconnected, and the first positive switch K2, the first negative switch K3, the second positive switch K6, the second negative switch K7 and the conduction state of the three-phase inverter bridge are controlled to be that the switch tubes VT2 / VT4 / VT6 are turned on, so that the first charging port 01 and the second charging port 04 charge the first battery pack 02 separately.

[0125] Similarly, Fig.17 is a charging principle diagram when the capacity of the second battery pack is unbalanced provided in Example 3 of the present invention, such as Fig.17 As shown, when the capacity of the second battery pack 03 is unbalanced, that is, the capacity of the second battery pack 03 is smaller than that of the first battery pack 02, the first charging port 01 and the second charging port 04 charge the second battery pack 03 separately, the control unit controls the first switch K1 to be disconnected and controls the conduction state of the three-phase inverter bridge to be other conduction states except that the switch tubes VT2 / VT4 / VT6 are turned on, and the control unit controls the first positive switch K2, the first negative switch K3, the second positive switch K6, the second negative switch K7, the fourth charging circuit switch and the second charging circuit switch K5 to be closed, so that the first charging port 01 and the second charging port 04 charge the second battery pack 03 separately to achieve capacity balance between the first battery pack 02 and the second battery pack 03.

[0126] Furthermore, in this embodiment, the three-phase inverter bridge adopts the three-phase inverter bridge in the original power motor of the electric vehicle, and the electric vehicle charging system is improved on the basis of the original electric vehicle, so as to further save costs and ensure the charging reliability of the electric vehicle charging system.

[0127] Fig.18 is a structural block diagram of an electric vehicle provided by Embodiment 3 of the present invention, such as Fig.18 As shown, this embodiment also provides an electric vehicle, including a power battery and the electric vehicle charging system as described above;

[0128] The power battery includes a first battery pack, a second battery pack and a first switch, and the first battery pack and the second battery pack are connected in series through the first switch.

[0129] Example 4

[0130] An embodiment of the present invention provides an electric vehicle charging system, comprising:

[0131] A first charging port, connected to the low-voltage DC charging pile;

[0132] A second charging port connected to the high-voltage DC charging pile; and

[0133] A control unit, wherein the control unit is used to control the first battery pack of the power battery and the first charging port to form a first charging circuit, control the second battery pack of the power battery and the first charging port to form a second charging circuit, control the first battery pack of the power battery and the second charging port to form a third charging circuit, and control the second battery pack of the power battery and the second charging port to form a fourth charging circuit when the first charging port is connected to a low-voltage DC charging pile. The power battery includes at least a first battery pack and a second battery pack.

[0134] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes. The schemes in the embodiments of the present invention may be implemented in various computer languages, for example, object-oriented programming language Java and literal scripting language JavaScript, etc.

[0135] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0136] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0137] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0138] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0139] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

[0140] The optional implementation modes of the present invention are described in detail above in conjunction with the accompanying drawings. However, the implementation modes of the present invention are not limited to the specific details in the above implementation modes. Within the technical concept of the implementation modes of the present invention, a variety of simple modifications can be made to the technical solutions of the implementation modes of the present invention, and these simple modifications all belong to the protection scope of the implementation modes of the present invention. It should also be noted that the various specific technical features described in the above specific implementation modes can be combined in any suitable manner without contradiction, and as long as the combination does not violate the concept of the implementation modes of the present invention, it should also be regarded as the content disclosed in the implementation modes of the present invention.

Claims

1. A method for charging a power battery of an electric vehicle, characterized in that: The method comprises: When the voltage of the first charging port of the electric vehicle is lower than the voltage of the power battery, the first battery pack of the power battery is controlled to form a first charging circuit with the first charging port, and the second battery pack of the power battery is controlled to form a second charging circuit with the first charging port, and the power battery includes at least a first battery pack and a second battery pack.

2. The method for charging a power battery of an electric vehicle according to claim 1, characterized in that: The method further comprises: When the voltage of the first charging port is higher than the voltage of the power battery, the power battery and the first charging port are controlled to form a charging loop.

3. The method for charging a power battery of an electric vehicle according to claim 1, characterized in that: The method further comprises: When the capacity of the first battery pack is less than the capacity of the second battery pack, controlling the first battery pack and the first charging port to form a balanced charging loop; When the capacity of the second battery pack is smaller than the capacity of the first battery pack, the second battery pack and the first charging port are controlled to form a balanced charging loop.

4. A method for charging a power battery of an electric vehicle, characterized in that: The method comprises: When the voltage of the first charging port of the electric vehicle is lower than the voltage of the power battery, the first battery pack of the power battery and the first charging port are controlled to form a first charging circuit, and the second battery pack of the power battery and the first charging port are controlled to form a second charging circuit. When the voltage of the second charging port of the electric vehicle is lower than the voltage of the power battery, the first battery pack and the second charging port are controlled to form a third charging circuit, and the second battery pack and the second charging port are controlled to form a fourth charging circuit, and the power battery includes at least the first battery pack and the second battery pack.

5. The method for charging a power battery of an electric vehicle according to claim 4, characterized in that: The method further comprises: When the voltage of the first charging port is higher than the voltage of the power battery, the power battery and the first charging port are controlled to form a charging circuit. When the voltage of the second charging port is higher than the voltage of the power battery, the power battery and the second charging port are controlled to form a charging loop.

6. The method for charging a power battery of an electric vehicle according to claim 4, characterized in that: The method further comprises: When the capacity of the first battery pack is less than the capacity of the second battery pack, controlling the first battery pack and the first charging port to form a balanced charging loop, and the first battery pack and the second charging port to form a balanced charging loop; When the capacity of the second battery pack is smaller than that of the first battery pack, the second battery pack and the first charging port are controlled to form a balanced charging loop, and the second battery pack and the second charging port are controlled to form a balanced charging loop.

7. An electric vehicle charging system, characterized in that: include: First charging port; as well as A control unit, wherein the control unit is used to control a first battery pack of the power battery and the first charging port to form a first charging circuit, and to control a second battery pack of the power battery and the first charging port to form a second charging circuit when the voltage of the first charging port is lower than the voltage of the power battery of the electric vehicle, wherein the power battery comprises at least a first battery pack and a second battery pack.

8. The electric vehicle charging system according to claim 7, characterized in that: The control unit is further configured to control the power battery and the first charging port to form a charging circuit when the voltage of the first charging port is higher than the voltage of the power battery.

9. An electric vehicle charging system, characterized in that: include: First charging port; Second charging port; as well as A control unit, the control unit is used to control the first battery pack of the power battery and the first charging port to form a first charging circuit, control the second battery pack of the power battery and the first charging port to form a second charging circuit, control the first battery pack of the power battery and the second charging port to form a third charging circuit, and control the second battery pack of the power battery and the second charging port to form a fourth charging circuit when the voltage of the first charging port or the voltage of the second charging port is lower than the voltage of the power battery of the electric vehicle, the power battery comprising at least the first battery pack and the second battery pack.

10. The electric vehicle charging system according to claim 9, characterized in that: The control unit is further configured to control the power battery to form a charging circuit with the first charging port and the power battery to form a charging circuit with the second charging port when the voltage of the first charging port and the voltage of the second charging port are both higher than the voltage of the power battery.

11. The electric vehicle charging system according to claim 9, characterized in that: The first charging circuit includes a first charging circuit switch, and the control unit is used to control the conduction state of the first charging circuit by controlling the opening and closing of the first charging circuit switch; The second charging circuit includes a second charging circuit switch, and the control unit is used to control the conduction state of the second charging circuit by controlling the opening and closing of the second charging circuit switch; The third charging circuit includes a third charging circuit switch, and the control unit is used to control the conduction state of the third charging circuit by controlling the opening and closing of the third charging circuit switch; The fourth charging circuit includes a fourth charging circuit switch, and the control unit is used to control the conduction state of the fourth charging circuit by controlling the opening and closing of the fourth charging circuit switch.

12. The electric vehicle charging system according to claim 11, characterized in that: The first charging circuit switch is a three-phase inverter bridge.

13. The electric vehicle charging system according to claim 11 or 12, characterized in that: The third charging circuit switch is the same switch as the first charging circuit switch, and the fourth charging circuit switch is the same switch as the second charging circuit switch.

14. An electric vehicle charging system, characterized in that: include: First charging port; Second charging port; as well as A control unit, the control unit is used to control the first battery pack of the power battery and the first charging port to form a first charging circuit, control the second battery pack of the power battery and the first charging port to form a second charging circuit, control the first battery pack of the power battery and the second charging port to form a third charging circuit, and control the second battery pack of the power battery and the second charging port to form a fourth charging circuit when the voltage of the first charging port is lower than the voltage of the power battery of the electric vehicle and the voltage of the second charging port is higher than the voltage of the power battery of the electric vehicle, the power battery comprises at least a first battery pack and a second battery pack.

15. An electric vehicle, characterized in that: The invention comprises an electric vehicle charging system as claimed in any one of claims 7 to 14.

16. The electric vehicle according to claim 15, characterized in that: The electric vehicle further includes a power battery, which includes at least a first battery pack and a second battery pack, wherein the first battery pack and the second battery pack are connected in series via a first switch.

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