Method for charging an electric vehicle and electric system of an electric vehicle

Abstract

An electric vehicle includes an electrical system and performs a method of charging the electric vehicle. The electrical system includes a first battery sub-pack, a second battery sub-pack, and a processor, wherein the first battery sub-pack, the second battery sub-pack, and an electrical load of the electric vehicle are connected in parallel. The processor is configured to control a first connection between the first battery sub-pack and a first charging port and a second connection between the second battery sub-pack and a second charging port to charge each of the first battery sub-pack and the second battery sub-pack while providing power to the electrical load.

Description

Technical Field

[0001] This subject matter relates to electric vehicles, and more particularly to systems for charging multiple battery sub-packs of electric vehicles. Background Technology

[0002] Medium and heavy-duty electric vehicles operate using high-voltage battery power sources. Charging these battery power sources can be a time-consuming operation due to the required charge amount and limitations on the charging rate to prevent overheating. Therefore, there is a need for a battery system capable of charging with reduced charging time. Summary of the Invention

[0003] In one exemplary embodiment, a method for charging an electric vehicle is disclosed. The method includes controlling a first connection between a first battery sub-pack and a first charging port and a second connection between a second battery sub-pack and a second charging port via a processor to charge each of the first and second battery sub-packs while providing power to an electrical load, wherein the first battery sub-pack, the second battery sub-pack, and the electrical load of the electric vehicle are connected in parallel.

[0004] In addition to one or more features described herein, the method further includes supplying power from a first battery subgroup and a second battery subgroup to an electrical load while charging using only one of the first and second charging ports. The method also includes charging the first battery subgroup via the first charging port and charging the second battery subgroup via the second charging port while supplying power to the electrical load using only one of the first and second battery subgroups. The method further includes performing a pre-charge operation at a corresponding location in one of the first and second battery subgroups before charging the first and second battery subgroups. Performing the pre-charge operation further includes one of: pre-charging one of a first pre-charge resistor associated with the first battery subgroup and a second pre-charge resistor associated with the second battery subgroup; controlling one of a first solid-state relay associated with the first battery subgroup and a second solid-state relay associated with the second battery subgroup; and pre-charging using a resistor shared by the first and second battery subgroups. The method further includes one of the following: in the event of an overcurrent at the first charging port, blowing a first charging port fuse at the first charging port; during separate charging of the first battery sub-pack, detecting an overcurrent at the first charging port via a first charging port current sensor associated with the first charging port, and blowing a first high-temperature fuse associated with the first battery sub-pack in response to a signal from the first charging port current sensor; and during charging of the first battery sub-pack and the second battery sub-pack, detecting an overcurrent at the first charging port via a first charging port current sensor associated with the first charging port, and blowing a first high-temperature fuse associated with the first battery sub-pack and a second high-temperature fuse associated with the second battery sub-pack in response to a signal from the first charging port current sensor. In various embodiments, either the first connection and the second connection are electrically isolated, and the first charging port and the second charging port are electrically connected to each other, or both are present.

[0005] In another exemplary embodiment, an electrical system for an electric vehicle is disclosed. The electrical system includes a first battery sub-pack, a second battery sub-pack, and a processor, wherein the first battery sub-pack, the second battery sub-pack, and an electrical load of the electric vehicle are connected in parallel. The processor is configured to control a first connection between the first battery sub-pack and a first charging port and a second connection between the second battery sub-pack and a second charging port to charge each of the first and second battery sub-packs while providing power to the electrical load.

[0006] In addition to one or more features described herein, the processor is configured to control the first and second connections to supply power from the first and second battery sub-groups to an electrical load while charging only one of the first and second battery sub-groups. The processor is also configured to control the first and second connections to charge the first battery sub-group via a first charging port and the second battery sub-group via a second charging port while supplying power to the electrical load only through one of the first and second battery sub-groups. The processor is further configured to perform a pre-charge operation at a corresponding location in one of the first and second battery sub-groups before charging the first and second battery sub-groups. Performing the pre-charge operation further includes one of: pre-charging one of a first pre-charge resistor associated with the first battery sub-group and a second pre-charge resistor associated with the second battery sub-group; controlling one of a first solid-state relay associated with the first battery sub-group and a second solid-state relay associated with the second battery sub-group; and using a resistor shared by the first and second battery sub-groups for pre-charging. The electrical system further includes one of the following: a first charging port fuse configured to blow in the event of an overcurrent at the first charging port; a first charging port current sensor configured to send a signal when an overcurrent is detected at the first charging port; and a first high-temperature fuse associated with a first battery sub-group and a second high-temperature fuse associated with a second battery sub-group, wherein the first high-temperature fuse is configured to blow in response to a signal during the individual charging of the first battery sub-group, and the first and second high-temperature fuses are configured to blow in response to a signal during the charging of both the first and second battery sub-groups. In various embodiments, either the first connection and the second connection are electrically isolated, and the first and second charging ports are electrically connected to each other, or both.

[0007] In another exemplary embodiment, an electric vehicle is disclosed. The electric vehicle includes a first battery sub-pack, a second battery sub-pack, and a processor, wherein the first battery sub-pack, the second battery sub-pack, and an electrical load of the electric vehicle are connected in parallel. The processor is configured to control a first connection between the first battery sub-pack and a first charging port, and a second connection between the second battery sub-pack and a second charging port, to charge each of the first and second battery sub-packs while providing power to the electrical load.

[0008] In addition to one or more features described herein, the processor is configured to control a first connection and a second connection to supply power from the first battery subgroup and the second battery subgroup to an electrical load while charging only one of the first battery subgroup and the second battery subgroup. The processor is also configured to control the first connection and the second connection to charge the first battery subgroup via a first charging port and the second battery subgroup via a second charging port while supplying power to the electrical load only through one of the first battery subgroup and the second battery subgroup. The processor is also configured to perform a pre-charge operation at a corresponding location in one of the first battery subgroup and the second battery subgroup before charging one of them. The pre-charge operation is performed at one of the following locations: a first pre-charge resistor associated with the first battery subgroup and a second pre-charge resistor associated with the second battery subgroup; a first solid-state relay associated with the first battery subgroup and a second solid-state relay associated with the second battery subgroup; and a resistor shared by the first battery subgroup and the second battery subgroup. The electric vehicle further includes one of the following: a first charging port fuse configured to blow in the event of an overcurrent at the first charging port; a first charging port current sensor configured to send a signal when an overcurrent is detected at the first charging port; and a first high-temperature fuse associated with a first battery sub-pack and a second high-temperature fuse associated with a second battery sub-pack, wherein the first high-temperature fuse is configured to blow in response to a signal during separate charging of the first battery sub-pack, and the first and second high-temperature fuses are configured to blow in response to a signal during charging of both the first and second battery sub-packs. In various embodiments, either the first connection and the second connection are electrically isolated, and the first and second charging ports are electrically connected to each other, or both are present.

[0009] The above-described features and advantages, as well as other features and advantages, of this disclosure will become apparent from the following detailed description when taken in conjunction with the accompanying drawings. Attached Figure Description

[0010] Other features, advantages, and details appear only by way of example in the following detailed description, which refers to the accompanying drawings, wherein:

[0011] Figure 1 An electric vehicle according to an exemplary embodiment is shown;

[0012] Figure 2 A circuit diagram of the electrical system of the electric vehicle in the first embodiment is shown;

[0013] Figure 3 A circuit diagram of the electrical system in the second embodiment is shown;

[0014] Figure 4 A circuit diagram of the electrical system in the third embodiment is shown;

[0015] Figure 5 A circuit diagram of the electrical system in the fourth embodiment is shown; and

[0016] Figure 6 A circuit diagram of the electrical system in the fifth embodiment is shown. Detailed Implementation

[0017] The following description is exemplary in nature only and is not intended to limit this disclosure, its application, or use. It should be understood that in all the drawings, corresponding reference numerals denote the same or corresponding parts and features.

[0018] According to an exemplary embodiment, Figure 1 An electric vehicle 100 is shown. The electric vehicle 100 includes an electrical system 102, which includes a battery system 104 and an electrical load 106 that operates using power provided by the battery system. The electrical load 106 may include accessory loads such as a radio, air conditioner, power windows, etc. Figure 1 As shown, the vehicle is plugged into charging station 110, which charges battery system 104.

[0019] The electric vehicle 100 also includes a controller 112. The controller 112 may include processing circuitry, which may include application-specific integrated circuits (ASICs), electronic circuitry, a processor (shared, dedicated, or grouped) executing one or more software or firmware programs, memory, combinational logic circuitry, and / or other suitable components providing the aforementioned functionality. The controller 112 may include a non-transitory computer-readable medium storing instructions that, when processed by one or more processors of the controller 112, implement a method for controlling the charging operation of the battery system 104.

[0020] Figure 2 A circuit diagram 200 of the electrical system 102 of the electric vehicle 100 in a first embodiment is shown. The electrical system 102 includes a first battery sub-pack 202 and a second battery sub-pack 204. The first battery sub-pack 202 and the second battery sub-pack 204 are high-voltage battery sub-packs. In one embodiment, at least one of the first battery sub-pack 202 and the second battery sub-pack 204 can maintain a voltage of 800 volts (V) when fully charged. The first battery sub-pack 202 includes a first positive terminal 206 and a first negative terminal 208. The second battery sub-pack 204 includes a second positive terminal 210 and a second negative terminal 212. The first battery sub-pack 202 and the second battery sub-pack 204 can be connected in parallel to each other and are connected in parallel to the vehicle propulsion and accessory load 270 of the electrical load 106 via a high-voltage (HV) positive bus 272 at the positive terminal and an HV negative bus 274 at the negative terminal.

[0021] A first pre-charge device 214 and a first main switch 216 (SA1) are located between the first positive terminal 206 of the first battery sub-pack 202 and the HV positive bus 272. The first pre-charge device 214 runs parallel to the first main switch 216 (SA1) and includes a first pre-charge switch 218 (PCA) and a first pre-charge resistor 220. In normal operation, the first main switch 216 (SA1) is closed and the first pre-charge switch 218 (PCA) is open, allowing current to bypass the first pre-charge resistor 220. During pre-charge operation, the first main switch 216 (SA1) is open and the first pre-charge switch 218 (PCA) is closed, allowing current to flow through the first pre-charge resistor 220, thereby limiting inrush current along the HV positive bus 272 and at the vehicle propulsion and accessory load 270.

[0022] The first return switch 230 (SA2), the first high-temperature fuse 232 (Pyro 1), and the first subgroup / charging port current sensor 234 are located between the first negative terminal 208 and the HV negative bus 274.

[0023] During the key-on event, both the first return switch 230 (SA2) and the precharge switch 218 are closed, allowing the first sub-group 202 to power the HV positive bus 272. The precharge resistor 220 prevents high inrush current along the HV positive bus 272. Once the HV positive bus 272 reaches a voltage level close to the battery sub-group voltage, the precharge process is complete. Then, the first precharge switch 218 opens, and the first main switch 216 closes.

[0024] Similarly, the second pre-charge device 222 and the second main switch 224 (SB1) are located between the second positive terminal 210 and the HV positive bus 272 of the second battery sub-pack 204. The second pre-charge device 222 runs parallel to the second main switch 224 (SB1) and includes a second pre-charge switch 226 (PCB) and a second pre-charge resistor 228. In normal operation, the second main switch 224 (SB1) is closed and the second pre-charge switch 226 (PCB) is open, allowing current to bypass the second pre-charge resistor 228. During pre-charge operation, the second main switch 224 (SB1) is open and the second pre-charge switch 226 (PCB) is closed, allowing current to flow through the second pre-charge resistor 228, thereby limiting the inrush current along the HV positive bus 272 and at the push and accessory load 270.

[0025] The second return switch 236 (SB2), the second high-temperature fuse 238 (Pyro 2), and the second subgroup / charging port current sensor 239 are located between the second negative terminal 212 and the HV negative bus 274.

[0026] During a key-on event, the second return switch 236 and the second precharge switch 226 can be closed, allowing the second battery sub-pack 204 to power the HV bus 272. The precharge resistor 228 prevents high inrush current along the HV positive bus 272. Once the HV positive bus 272 reaches a voltage close to that of the second battery sub-pack 204, the precharge process is complete. The second precharge switch 226 then opens, and the second main switch 224 closes.

[0027] If the first battery sub-group 202 is connected to the HV positive bus 272 for pre-charging, then by closing the second main switch 224 and the second return switch 236, the second battery sub-group 204 can be connected in parallel to pre-charge the first battery sub-group 202 simultaneously, without the need for a second pre-charging device 222. Similarly, if the second battery sub-group 204 is connected to the HV positive bus for pre-charging, then by closing the first main switch 216 and the first return switch 230, the first battery sub-group 202 can be connected in parallel with the second battery sub-group 204 without the need for a first pre-charging device 214.

[0028] During charging operation, the first battery sub-pack 202 can be coupled to a first charging port 240, through which it is connected to the charging station 110. In various embodiments, the first charging port 240 is a DC fast charging (DCFC) port. The first charging port 240 includes a first positive charging terminal 242 and a first negative charging terminal 244. The first positive charging terminal 242 is connected to a first positive terminal 206 of the first battery sub-pack 202. The first negative charging terminal 244 is connected between a first return switch 230 (SA2) and a first fuse 232 (Pyro 1). A switch 246 (SA3) at the first positive charging terminal 242 controls the connection between the first positive charging terminal and the first positive terminal 206. A switch 248 (SA4) at the first negative charging terminal 244 controls the connection between the first negative charging terminal and the first negative terminal 208. A first charging port fuse 260 is located at the first positive charging terminal 242 and can be activated or blown in the event of an overcurrent.

[0029] Similarly, during charging operation, the second battery sub-pack 204 can be coupled to a second charging port 250, through which it is connected to the charging station 110. In various embodiments, the second charging port 250 is a DC fast charging (DCFC) port. The second charging port 250 includes a second positive charging terminal 252 and a second negative charging terminal 254. The second positive charging terminal 252 is connected to the second positive terminal 210 of the second battery sub-pack 204. The second negative charging terminal 254 is connected between a second return switch 236 (SB2) and a second fuse 238 (Pyro 2). A switch 256 (SB3) at the second positive charging terminal 252 controls the connection between the second positive charging terminal 252 and the second positive terminal 210. Similarly, a switch 258 (SB4) at the second negative charging terminal 254 controls the connection between the second negative charging terminal 254 and the second negative terminal 212. A second charging port fuse 262 is located at the second positive charging terminal 252 and can be activated or blown in the event of an overcurrent.

[0030] Controller 112 can be coupled to each switch (i.e., SA1, SA2, SA3, SA4, PCA, Pyro 1, SB1, SB2, SB3, SB4, PCB, Pyro 2) and can control the operation of the switches. Controller 112 can switch the configuration of these switches to suit a given operating mode of the battery sub-pack. Note that the first charging port 240 is used to charge the first battery sub-pack 202, and the second charging port 250 is used to charge the second battery sub-pack 204. Table 1 shows various exemplary operating modes and their associated switching configurations.

[0031] Table 1

[0032]

[0033] Table 1 or a similar table may be stored in a storage device. In various embodiments, the controller 112 can access this table when the vehicle is placed in one of the illustrated modes. The controller 112 can then change the configuration of the switches as shown in the entries in the table.

[0034] The controller 112 can control the connection between the first battery sub-pack 202 and the first charging port 240, and the connection between the second battery sub-pack 204 and the second charging port 250. These connections can be made to charge the first battery sub-pack 202 and the second battery sub-pack 204 individually or together. The battery sub-packs can be connected to charge and power accessory loads simultaneously. The two sub-packs can be connected in parallel and charged from either charging port or simultaneously from both charging ports.

[0035] During parallel charging operation using a single charging port, only one battery sub-pack is connected to its charging port for charging, while both battery sub-packs are connected in parallel to the accessory load 270. In individual charging operation, both battery sub-packs are connected to their respective charging ports, while only one sub-pack is connected to the accessory load.

[0036] The controller can also send a switch to a configuration for performing a pre-charge operation at one of the first and second battery sub-groups. This configuration can be performed before charging operations at either the first or second battery sub-group.

[0037] Figure 2 The electrical system allows for the support of accessory loads during charging operations. A pre-charging device protects the accessory loads from current inrush. Sub-packs can be charged simultaneously in parallel or individually through each charging port. Therefore, a single charging port can be used without the other. Sensors obtain measurements of various parameters of the electrical system, such as voltage, current, temperature, etc. These measurements can be used to control the charging current drawn from the charging ports. In one embodiment, one charging port may be on one side of the vehicle, while the other may be on the other side. Although two battery sub-packs are shown here, it should be understood that any number of battery sub-packs can be used in other embodiments of the electrical system.

[0038] Figure 3 A circuit diagram 300 of the electrical system 102 in the second embodiment is shown. Instead of the first charging port fuse 260 shown in the first embodiment, a first charging port current sensor 302 is located at the first positive charging terminal 242. The first charging port current sensor 302 communicates with the controller 112 and sends a signal to the controller when an overcurrent is detected. When the first charging port is being used to charge only the first sub-group 202, and the current sensor 302 detects an overcurrent through the first charging port 240, the controller 112 sends a signal to the first fuse 232 (Pyro 1) to activate or deactivate (i.e., disconnect the circuit between the HV negative bus 274 and the first battery sub-group 202). When the first charging port 240 is being used to charge the first sub-group 202 and the second sub-group 204 in parallel, and the current sensor 302 detects an overcurrent through the first charging port 240, the controller 112 sends signals to the first fuse 232 (Pyro 1) and the second fuse 238 (Pyro 2) to activate or deactivate (i.e. disconnect the circuit between the HV negative bus 274 and the first battery sub-group 202 and the second battery sub-group 204).

[0039] Similarly, a second charging port current sensor 304 is located at the second positive charge terminal 252. The second charging port current sensor 304 communicates with the controller 112 and sends a signal to the controller when an overcurrent is detected. When the second charging port is being used to charge only the second sub-group 204, and the current sensor 304 detects an overcurrent through the second charging port 250, the controller 112 sends a signal to the second fuse 238 (Pyro 2) to activate or deactivate (i.e., disconnect the circuit between the HV negative bus 274 and the second battery sub-group 204). When the second charging port is being used to charge the first sub-group 202 and the second sub-group 204 in parallel, and the current sensor 304 detects an overcurrent through the second charging port 250, the controller 112 sends signals to the first fuse 232 (Pyro 1) and the second fuse 238 (Pyro 2) to activate or deactivate (i.e., disconnect the circuit between the HV negative bus 274 and the first battery sub-group 202 and the second battery sub-group 204).

[0040] Figure 4 A circuit diagram 400 of the electrical system 102 in the third embodiment is shown. Compared to the first embodiment, a first solid-state relay 402 (SSRA1) replaces the first pre-charge device 214 and the first main switch 216. Furthermore, switch 246 (SA3) has been replaced by a second solid-state relay 404 (SSRA3) at the first positive charging terminal 242. Controller 112 can turn the first solid-state relay 402 on or off, or make it act as a variable resistor. Additionally, controller 112 can turn the second solid-state relay 404 on or off. The first fuse 232 (Pyro 1) has been removed together. The positions of solid-state relay 402 and switch 230 (SA2) can be interchanged. Similarly, the positions of solid-state relay 404 and switch 248 (SA4) can be interchanged. In another embodiment, all switches can be solid-state type.

[0041] A third solid-state relay 406 (SSRB1) replaces the second pre-charging device 222 and the main switch 224 of the first embodiment. Furthermore, switch 256 has been replaced by a fourth solid-state relay 408 (SSRB3) at the second positive charging terminal 252. Controller 112 can turn the third solid-state relay 406 on or off, or make it function as a variable resistor. Additionally, controller 112 can turn the fourth solid-state relay 408 on or off. The second fuse 238 (Pyro 2) has been removed together. The positions of solid-state relay 406 and switch 236 can be interchanged. Similarly, the positions of solid-state relay 408 and switch 258 can be interchanged. In another embodiment, all switches can be solid-state type.

[0042] Figure 5A circuit diagram 500 of the electrical system 102 in the fourth embodiment is shown. The first pre-charge device 214 and the second pre-charge device 222 of the first embodiment have been replaced by a single pre-charge device 502, which includes a single resistor 504 shared between the first battery sub-group 202 and the second battery sub-group 204. The single pre-charge device 502 includes a first pre-charge switch 218 (PCA), a second pre-charge switch 226 (PCB), and a single pre-charge resistor 504. The first pre-charge switch 218 (PCA) and the second pre-charge switch 226 (PCB) are connected from the first battery sub-group 202 and the second battery sub-group 204 to a first terminal 506 of the single resistor 504, respectively. A first main switch 216 (SA1) and a second main switch 224 (SB1) are connected from their respective battery sub-groups to a second terminal 508 of the single resistor 504. The second terminal 508 is connected to the HV positive bus 272 of the propulsion and accessory load 270.

[0043] Figure 6 A circuit diagram 600 of the electrical system 102 in the fifth embodiment is shown. In the fifth embodiment, the first positive charging terminal 242 of the first charging port 240 is electrically connected to the second positive charging terminal 252 of the second charging port 250. These charging ports can be coupled to the first positive terminal 206 of the first battery sub-pack 202 and the second positive terminal 210 of the second battery sub-pack 204 via the first charging switch 602 (SC1).

[0044] Furthermore, the first negative charging terminal 244 of the first charging port 240 is electrically connected to the second negative charging terminal 254 of the second charging port 250. These charging ports can be connected via the second charging switch 604 (SC2) to the first negative terminal 208 of the first battery sub-pack 202 and the second negative terminal 212 of the second battery sub-pack 204.

[0045] Therefore, the first charging port and the second charging port are electrically connected to each other. This differs from the first embodiment, in which the first connection and the second connection are electrically isolated.

[0046] The terms “a” and “an” do not indicate a quantity limitation, but rather that at least one of the referenced items is present. The term “or” means “and / or”, unless the context clearly indicates otherwise. A reference to “an aspect” throughout the specification means that a particular element described in connection with that aspect (e.g., a feature, structure, step, or characteristic) is included in at least one aspect described herein and may or may not be present in other aspects. Furthermore, it should be understood that the described elements may be combined in any suitable manner across the aspects.

[0047] When an element, such as a layer, film, region, or substrate, is referred to as being "on" another element, it can be directly on the other element, or there may be intermediate elements present. Conversely, when an element is referred to as being "directly on" another element, there are no intermediate elements present.

[0048] Unless otherwise stated herein, all test standards are the most recent valid standards up to the date of filing of this application, or, if priority is claimed, the filing date of the earliest priority application in which the test standards appeared.

[0049] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0050] While the foregoing disclosure has been described with reference to exemplary embodiments, those skilled in the art will understand that various changes can be made and equivalents can replace its elements without departing from its scope. Furthermore, many modifications can be made to adapt particular situations or materials to the teachings of this disclosure without departing from its essential scope. Therefore, it is intended that this disclosure be limited to the specific embodiments disclosed, but will include all embodiments falling within its scope.

Claims

1. A method for charging an electric vehicle, comprising: The processor controls a first connection between the first battery sub-pack and the first charging port, and a second connection between the second battery sub-pack and the second charging port, to charge each of the first and second battery sub-packs while supplying power to the electrical load, wherein the first battery sub-pack, the second battery sub-pack, and the electrical load of the electric vehicle are connected in parallel. The method further includes one of the following: (i) in the event of an overcurrent at the first charging port, blowing a first charging port fuse at the first charging port; (ii) during separate charging of the first battery sub-pack, detecting an overcurrent at the first charging port via a first charging port current sensor associated with the first charging port, and blowing a first high-temperature fuse associated with the first battery sub-pack in response to a signal from the first charging port current sensor; and (iii) during charging of the first battery sub-pack and the second battery sub-pack, detecting an overcurrent at the first charging port via a first charging port current sensor associated with the first charging port, and blowing a first high-temperature fuse associated with the first battery sub-pack and a second high-temperature fuse associated with the second battery sub-pack in response to a signal from the first charging port current sensor. The method further includes performing a pre-charge operation at a corresponding location in the first battery sub-group and the second battery sub-group before charging one of them. Wherein, if the first battery subgroup is used for pre-charging, then the first battery subgroup is pre-charged simultaneously via a parallel connection of the second battery subgroup, without the need for a second pre-charging device. If the second battery subgroup is the first subgroup used for pre-charging, then the first battery subgroup and the second battery subgroup are connected in parallel, and a first pre-charging device is not required.

2. The method of claim 1, further comprising providing power from the first battery sub-group and the second battery sub-group to the electrical load when charging is performed using only one of the first charging port and the second charging port.

3. The method of claim 1, further comprising charging the first battery sub-group through the first charging port and charging the second battery sub-group through the second charging port when power is supplied to the electrical load only through one of the first battery sub-group and the second battery sub-group.

4. The method according to claim 1, wherein, Performing the pre-charge operation further includes one of the following: (i) pre-charging one of a first pre-charge resistor associated with the first battery sub-group and a second pre-charge resistor associated with the second battery sub-group; (ii) controlling one of a first solid-state relay associated with the first battery sub-group and a second solid-state relay associated with the second battery sub-group; (iii) Pre-charging is performed using a resistor shared by the first and second battery sub-groups.

5. An electrical system for an electric vehicle, comprising: First battery subgroup; The second battery sub-pack, wherein the first battery sub-pack, the second battery sub-pack, and the electric load of the electric vehicle are connected in parallel; as well as A processor configured to control a first connection between a first battery sub-pack and a first charging port, and a second connection between a second battery sub-pack and a second charging port, to charge each of the first and second battery sub-packs while supplying power to an electrical load. The electrical system further includes one of the following: (i) a first charging port fuse configured to blow in the event of an overcurrent at the first charging port; (ii) a first charging port current sensor configured to send a signal when an overcurrent is detected at the first charging port; and (iii) a first high-temperature fuse associated with a first battery sub-group and a second high-temperature fuse associated with a second battery sub-group, wherein the first high-temperature fuse is configured to blow in response to a signal during individual charging of the first battery sub-group, and the first and second high-temperature fuses are configured to blow in response to a signal during charging of both the first and second battery sub-groups. The processor is further configured to perform a pre-charge operation at a corresponding location in the first battery sub-group and the second battery sub-group before charging one of them. Wherein, if the first battery subgroup is used for pre-charging, then the first battery subgroup is pre-charged simultaneously via a parallel connection of the second battery subgroup, without the need for a second pre-charging device. If the second battery subgroup is the first subgroup used for pre-charging, then the first battery subgroup and the second battery subgroup are connected in parallel, and a first pre-charging device is not required.

6. The electrical system according to claim 5, wherein, The processor is also configured to control the first and second connections to provide power from the first and second battery sub-groups to the electrical load when only one of the first and second battery sub-groups is being charged.

7. The electrical system according to claim 5, wherein, The processor is also configured to control the first and second connections to charge the first battery sub-group via the first charging port and the second battery sub-group via the second charging port when power is supplied to the electrical load only through one of the first and second battery sub-groups.

8. The electrical system according to claim 5, wherein, Performing the pre-charge operation further includes one of the following: (i) pre-charging one of a first pre-charge resistor associated with the first battery sub-group and a second pre-charge resistor associated with the second battery sub-group; (ii) controlling one of a first solid-state relay associated with the first battery sub-group and a second solid-state relay associated with the second battery sub-group; (iii) Pre-charging is performed using a resistor shared by the first and second battery sub-groups.

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