A safe power-off system and method for new energy heavy-duty trucks

Abstract

This invention provides a safe power-off system and method for new energy heavy-duty trucks. By connecting a power-off delay relay in parallel with the manual switch, the manual switch can be directly disconnected without interrupting the key power supply when the vehicle is under high voltage. The wake-up power supply of the vehicle controller can still be maintained until the vehicle controller determines that the wake-up power supply can be disconnected, and then the vehicle controller goes into sleep mode. At the same time, the status of the manual switch is derived, and the relay controls the on / off of the wake-up power circuit of the vehicle controller when the key switch is in the ON position. When the key switch is in the ON position, the manual switch is disconnected, and the ON position signal of the vehicle controller also disappears. The vehicle controller then begins to execute the high-voltage power-off process. The high-voltage power-off process proposed in this invention is specifically divided into disconnecting the manual switch under normal high voltage conditions, disconnecting the manual switch when intelligent charging is activated, and disconnecting the manual switch when plugging in the charging gun.

Description

Technical Field

[0001] This invention relates to a safe power-off system and method for new energy heavy-duty trucks, belonging to the field of power management technology for new energy heavy-duty trucks. Background Technology

[0002] With the increasing popularity and market share of new energy commercial vehicles, it is inevitable that manual switches will be disconnected when the vehicle's high voltage is off, leading to damage to downstream loads. Current mainstream power-off methods lack protection against disconnecting manual switches for safe power-off. Furthermore, in actual use, the end market inevitably involves directly disconnecting manual switches to dump loads, further causing a surge in current to reverse-current and break down the front-end relays or fuses the moment the high-voltage load loses input, resulting in damage to the vehicle's high-voltage components. Summary of the Invention

[0003] The purpose of this invention is to provide a safe power-off system and method for new energy heavy trucks. By connecting a power-off delay relay in parallel at the manual switch, the manual switch can be directly disconnected without interrupting the key switch when the vehicle is under high voltage. The wake-up power of the VCU controller can still be maintained, allowing the vehicle to safely complete the unloading operation and execute the high-voltage process according to the set program. The high-voltage operation can be completed within the set time.

[0004] To achieve the above objectives / to solve the above technical problems, the present invention is implemented using the following technical solution.

[0005] In a first aspect, the present invention provides a safe power-off system for new energy heavy trucks, comprising: a battery, a first power-off delay relay, a VCU fuse, a key switch, a double-pole single-throw manual switch, a first diode, a delayed power-off fuse, a second power-off delay relay, and a VCU controller;

[0006] The positive terminal of the battery is connected to the first stationary contact of the double-pole single-throw manual switch and the moving contact of the first power-down delay relay. The stationary contact of the first power-down delay relay is connected to the first moving contact of the double-pole single-throw manual switch. The first moving contact of the double-pole single-throw manual switch is also connected to the stationary contact of the key switch and the stationary contact of the second power-down delay relay. The moving contact of the key switch is connected to the second moving contact of the double-pole single-throw manual switch. The second stationary contact of the double-pole single-throw manual switch is connected to the ON power-on terminal of the VCU controller through a first diode.

[0007] The moving contact of the second power-down delay relay is used to connect various high-voltage accessory relays. The high-voltage accessory relays include: a first power-down delay relay; the negative terminal of the coil of the second power-down delay relay is connected to the power-down delay control terminal controlled by the VCU; when the VCU controller is awakened, it outputs a low active signal to energize the coil and engage the second power-down delay relay; the positive terminal of the coil of the second power-down delay relay is connected to the first moving contact of a double-pole single-throw manual switch; the negative terminal of the coil of the first power-down delay relay is grounded; the positive terminal of the coil of the first power-down delay relay is connected to the moving contact of the second power-down delay relay; when the second power-down delay relay is closed, the coil of the first power-down delay relay is energized and engages the first power-down delay relay; and the negative terminal of the battery is grounded.

[0008] Furthermore, it also includes a second diode and a third diode; the A+ auxiliary power input system is connected to the ON power wake-up terminal of the VCU controller through the second diode, which is used to wake up the VCU controller when the charging gun is plugged in, and the VCU controller executes the charging high voltage logic;

[0009] The intelligent power replenishment system is connected to the ON power wake-up terminal of the VCU controller via a third diode, and is also connected to the intelligent power replenishment request signal terminal of the VCU controller. When the intelligent power replenishment system determines that the intelligent power replenishment function needs to be activated, it wakes up the VCU controller. At the same time, the intelligent power replenishment request signal terminal of the VCU controller is valid, and then the VCU controller executes the intelligent power replenishment logic.

[0010] Furthermore, it also includes a multi-in-one DC-DC input module, which is connected to the positive terminal of the battery and ground at its two ends, respectively, to convert the 600V high-voltage electricity of the vehicle's power battery into 27V low-voltage electricity to charge the battery.

[0011] Furthermore, a VCU fuse is provided between the first moving contact of the double-pole single-throw manual switch and the stationary contact of the key switch; a delayed power-off fuse is provided between the first moving contact of the double-pole single-throw manual switch and the stationary contact of the second power-off delay relay.

[0012] Secondly, the present invention provides a method for safely powering down a new energy heavy-duty truck based on the aforementioned new energy heavy-duty truck safe power-down system, comprising the following steps:

[0013] Turn the key switch to the ON position. When the key switch is closed, the manual switch is disconnected. When the conditions for the high-pressure process are met, the high-pressure process is executed.

[0014] When the high-voltage process is completed, the VCU controller controls the power-down delay control terminal to continue outputting a low level until a certain set delay time is reached;

[0015] When the VCU controller stops outputting a low level (low level), the power-down delay relay disconnects, and the vehicle stops drawing power from the battery.

[0016] Furthermore, the aforementioned high-pressure process conditions specifically include:

[0017] The VCU controller's ON position wake-up signal disappears for more than 1 second, and the current vehicle speed is determined to be less than 5 km / h.

[0018] When the ON signal of the VCU controller disappears, the VCU controller disables the motor controller and stops the motor from outputting torque. When the VCU controller receives feedback from the drive motor indicating a closed state, it stops enabling high-voltage auxiliary components (disabling high-voltage electrical appliances such as air pumps, oil pumps, DC-DC converters, air conditioners, PTC systems, and multi-function auxiliary drives). Afterward, the VCU controller monitors the hydrogen fuel cell controller's operating status, vehicle speed, and battery current. If the vehicle speed is less than 5 km / h, the absolute value of the battery current is less than 10A, and the hydrogen fuel cell controller's operating status is indicated as standby or fault (including communication loss with the hydrogen fuel cell controller), then... First, the main positive relay is disconnected, followed by the auxiliary drive relay, air conditioning relay, and PTC relay. After the VCU controller detects that the main positive relay is disconnected, it sends a rapid power-down command to the motor controller, causing the motor controller voltage to drop rapidly to a safe voltage range (below 36V). When the VCU controller receives the disconnected status of the main positive relay and auxiliary drive relay, it sends a high-voltage command. After receiving the command, the battery controller judges the main circuit current. When the main circuit current is <15A, it disconnects the main negative relay and no longer feeds back the high-voltage power-up status. When the VCU controller receives the disconnected status of the main negative relay from the battery controller, the high-voltage power-down is completed.

[0019] Furthermore, when the conditions for a high-pressure process are not met:

[0020] If the A+ charging wake-up signal or intelligent power replenishment signal of the VCU controller is valid, the VCU controller will not execute the high voltage process.

[0021] If the charging gun is plugged in, the A+ charging wake-up signal is continuously output to wake up the VCU controller. The VCU controller determines the current key switch position. If the key switch is not in the ON position and the smart charging signal is invalid, the VCU controller executes the charging high voltage logic.

[0022] If the battery voltage is below 24.5V, the intelligent power replenishment system will output an intelligent power replenishment signal to wake up the VCU controller. The VCU controller will determine the current key switch position. If the key switch is not in the ON position and the intelligent power replenishment signal is valid, the VCU controller will execute the intelligent power replenishment logic to increase or decrease the high voltage.

[0023] Furthermore, the calculation of the current vehicle speed specifically includes:

[0024] ;

[0025] In the formula, V Current vehicle speed n The output shaft speed of the gearbox. r For the tire radius, i g For the rear axle speed ratio, i 0 The main reducer transmission ratio.

[0026] Furthermore, the VCU controller controls the power-down delay control terminal to continue outputting a low level until a certain set delay time is reached, specifically including:

[0027] After the VCU controller is woken up, its power-down delay control terminal continuously outputs a low level;

[0028] Eight seconds after the VCU controller wake-up signal disappears, its power-down delay control terminal stops outputting a low level.

[0029] Furthermore, the VCU controller stops outputting a low level, the power-down delay relay disconnects, and the vehicle stops drawing power from the battery. Specifically, this includes:

[0030] The second power-down delay relay coil is de-energized, and then the moving contact of the second power-down delay relay opens, de-energizing all high-voltage accessory relays and the first power-down delay relay coil.

[0031] The coil of the first power-down delay relay is de-energized, and then the moving contact of the first power-down delay relay opens, stopping the vehicle from drawing power from the battery.

[0032] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: By connecting a power-down delay relay in parallel at the manual switch, the present invention enables the manual switch to be directly disconnected without interrupting the key power when the vehicle is under high voltage, while the wake-up power of the vehicle controller can still be maintained until the vehicle controller determines that the wake-up power can be disconnected at this time, and then the vehicle controller goes into sleep mode. This allows the unloading operation to be completed safely, and the high-voltage process to be executed according to the set procedure. The high-voltage operation can be completed within the set time, which is safe and efficient.

[0033] When the vehicle is in different states (normal high-voltage mode, charging high-voltage mode, and intelligent charging mode), disconnecting the manual switch ensures normal high-voltage operation of the downstream load, preventing relay sticking or IGBT breakdown, as well as motor or battery damage, thus ensuring the safety of the vehicle's high-voltage system. Attached Figure Description

[0034] Figure 1 The diagram shown is a schematic diagram of a safe power-off system for new energy heavy trucks. Detailed Implementation

[0035] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations thereof. In the absence of conflict, the embodiments of the present invention and the technical features in the embodiments can be combined with each other.

[0036] The term "and / or" simply describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. Additionally, the character " / " generally indicates that the preceding and following related objects have an "or" relationship. Example

[0037] like Figure 1 As shown in one embodiment, this embodiment 1 provides a safe power-off system for new energy heavy trucks, including: a battery 2, a first power-off delay relay 6, a VCU fuse 10, a key switch 8, a double-pole single-throw manual switch 7, a first diode 4, a delayed power-off fuse 9, a second power-off delay relay 5, and a VCU controller 1;

[0038] The positive terminal of the battery 2 is connected to the first stationary contact of the double-pole single-throw manual switch 7 and the moving contact of the first power-down delay relay 6. The stationary contact of the first power-down delay relay 6 is connected to the first moving contact of the double-pole single-throw manual switch 7. The first moving contact of the double-pole single-throw manual switch 7 is also connected to the stationary contact of the key switch 8 and the stationary contact of the second power-down delay relay 5. The moving contact of the key switch 8 is connected to the second moving contact of the double-pole single-throw manual switch 7. The second stationary contact of the double-pole single-throw manual switch 7 is connected to the ON power-on terminal 15 of the VCU controller 1 through the first diode 4. The moving contact of the second power-down delay relay 5 is used to connect to each high-voltage accessory relay 14. The relay 14 includes: a first power-off delay relay 6; the negative terminal of the coil of the second power-off delay relay 5 is connected to the power-off delay control terminal 17 of the VCU control, and when the VCU controller 1 is woken up, it outputs a low active signal to energize the coil and close the second power-off delay relay 5; the positive terminal of the coil of the second power-off delay relay 5 is connected to the first moving contact of the double-pole single-throw manual switch 7; the negative terminal of the coil of the first power-off delay relay 6 is grounded; the positive terminal 11 of the coil of the first power-off delay relay 6 is connected to the moving contact of the second power-off delay relay 5; when the second power-off delay relay 5 is closed, the coil of the first power-off delay relay 6 is energized and closes the first power-off delay relay 6; and the negative terminal of the battery 2 is grounded.

[0039] It also includes a second diode and a third diode; the A+ auxiliary power input system 12 is connected to the ON power wake-up terminal 15 of the VCU controller 1 through the second diode, which is used to wake up the VCU controller 1 when the charging gun is plugged in, and the VCU controller 1 executes the charging high voltage logic.

[0040] The intelligent power replenishment system 13 is connected to the ON power wake-up terminal 15 of the VCU controller 1 via a third diode, and the intelligent power replenishment system 13 is also connected to the intelligent power replenishment request signal terminal 16 of the VCU controller 1. When the intelligent power replenishment system 13 determines that the intelligent power replenishment function needs to be activated, it wakes up the VCU controller 1, and at the same time, the intelligent power replenishment request signal terminal 16 of the VCU controller 1 is valid, so the VCU controller 1 executes the intelligent power replenishment logic.

[0041] It also includes a multi-in-one DC-DC input module 3, which is connected to the positive terminal of the battery 2 and ground at both ends, and is used to convert the 600V high voltage of the vehicle's power battery into 27V low voltage to charge the battery 2.

[0042] A VCU fuse 10 is provided between the first moving contact of the double-pole single-throw manual switch 7 and the stationary contact of the key switch 8; a delayed power-off fuse 9 is provided between the first moving contact of the double-pole single-throw manual switch 7 and the stationary contact of the second power-off delay relay 5. Example

[0043] This embodiment provides a safe power-off method for a new energy heavy truck, including the following steps: turn the key switch to the ON position, close the key ON position switch, disconnect the manual switch, and execute the high-voltage process when the conditions for the high-voltage process are met;

[0044] When the VCU controller's ON wake-up signal disappears for more than 1 second, the VCU controller disables the motor controller and stops the motor's torque output. When the VCU controller receives feedback from the drive motor indicating a closed state, it stops enabling high-voltage auxiliary components (disabling high-voltage electrical appliances such as air pumps, oil pumps, DC-DC converters, air conditioners, PTC converters, and multi-function auxiliary drives). Afterward, the VCU controller monitors the hydrogen fuel cell controller's operating status, vehicle speed, and battery current. When the vehicle speed is less than 5 km / h, the absolute value of the battery current is less than 10A, and the hydrogen fuel cell controller's operating status is indicated as standby or fault (including hydrogen fuel cell controller communication), the VCU controller will detect these issues. After the main positive relay is lost, the auxiliary drive relay, air conditioner relay, and PTC relay are disconnected first. After the VCU controller detects that the main positive relay is disconnected, it sends a rapid power-down command to the motor controller, causing the motor controller voltage to drop rapidly to a safe voltage range (below 36V). When the VCU controller receives the disconnected status of the main positive relay and the auxiliary drive relay, it sends a high-voltage command. After receiving the command, the battery controller judges the main circuit current. When the main circuit current is <15A, it disconnects the main negative relay and no longer feeds back the high-voltage power-up status. When the VCU controller receives the disconnected status of the main negative relay from the battery controller, the high-voltage power-down is completed.

[0045] The calculation of the current vehicle speed specifically includes:

[0046] ;

[0047] In the formula, V Current vehicle speed n The output shaft speed of the gearbox. r For the tire radius, i g For the rear axle speed ratio, i 0 The main reducer transmission ratio.

[0048] When the conditions for a high-pressure process are not met:

[0049] If the A+ charging wake-up signal or intelligent power replenishment signal of the VCU controller is valid, the VCU controller will not execute the high voltage process.

[0050] If the charging gun is plugged in, the A+ charging wake-up signal is continuously output to wake up the VCU controller. The VCU controller determines the current key switch position. If the key switch is not in the ON position and the smart charging signal is invalid, the VCU controller executes the charging high voltage logic.

[0051] If the battery voltage is below 24.5V, the intelligent power replenishment system will output an intelligent power replenishment signal to wake up the VCU controller. The VCU controller will determine the current key switch position. If the key switch is not in the ON position and the intelligent power replenishment signal is valid, the VCU controller will execute the intelligent power replenishment logic to increase or decrease the high voltage.

[0052] When the high-voltage process is completed, the VCU controller controls the power-down delay control terminal to continue outputting a low level until a certain set delay time is reached, specifically including:

[0053] After the VCU controller is woken up, its power-down delay control terminal continuously outputs a low level;

[0054] Eight seconds after the VCU controller wake-up signal disappears, its power-down delay control terminal stops outputting a low level.

[0055] The VCU controller stops outputting a low level, the power-down delay relay disconnects, and the vehicle stops drawing power from the battery. Specifically, this includes:

[0056] The second power-down delay relay coil is de-energized, and then the moving contact of the second power-down delay relay opens, de-energizing all high-voltage accessory relays and the first power-down delay relay coil.

[0057] The coil of the first power-down delay relay is de-energized, and then the moving contact of the first power-down delay relay opens, stopping the vehicle from drawing power from the battery.

[0058] When the vehicle is under high pressure, if the manual switch is directly disconnected, the vehicle can safely complete the unloading operation and execute the high-pressure process according to the set procedure. The high-pressure operation can be completed within the set time, which is safe and efficient.

[0059] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0060] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0061] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0062] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0063] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A safe power-off system for new energy heavy-duty trucks, characterized in that, include: Storage battery, first power-down delay relay, key switch, double-pole single-throw manual switch, first diode, second power-down delay relay and VCU controller; The positive terminal of the battery is connected to the first stationary contact of the double-pole single-throw manual switch and the moving contact of the first power-down delay relay. The stationary contact of the first power-down delay relay is connected to the first moving contact of the double-pole single-throw manual switch. The first moving contact of the double-pole single-throw manual switch is also connected to the stationary contact of the key switch and the stationary contact of the second power-down delay relay. The moving contact of the key switch is connected to the second moving contact of the double-pole single-throw manual switch. The second stationary contact of the double-pole single-throw manual switch is connected to the ON power-on terminal of the VCU controller through the first diode. The moving contact of the second power-down delay relay is used to connect to each high-voltage accessory relay. The negative terminal of the coil of the second power-down delay relay is connected to the power-down delay control terminal of the VCU controller. When the VCU controller is woken up, it outputs a low active signal to energize the coil and engage the second power-down delay relay. The positive terminal of the coil of the second power-down delay relay is connected to the first moving contact of the double-pole single-throw manual switch. The negative terminal of the coil of the first power-down delay relay is grounded, and the positive terminal of the coil of the first power-down delay relay is connected to the moving contact of the second power-down delay relay. When the second power-down delay relay is closed, the coil of the first power-down delay relay is energized and the first power-down delay relay is attracted. The negative terminal of the battery is grounded. The high-voltage accessory relay includes: the first power-down delay relay.

2. The new energy heavy truck safety power-off system according to claim 1, characterized in that, It also includes a second diode and a third diode; the A+ auxiliary power input system is connected to the ON power wake-up terminal of the VCU controller through the second diode, which is used to wake up the VCU controller when the charging gun is plugged in, and the VCU controller executes the charging high voltage logic; The intelligent power replenishment system is connected to the ON power wake-up terminal of the VCU controller via a third diode, and is also connected to the intelligent power replenishment request signal terminal of the VCU controller. When the intelligent power replenishment system determines that the intelligent power replenishment function needs to be activated, it wakes up the VCU controller. At the same time, the intelligent power replenishment request signal terminal of the VCU controller is valid, and then the VCU controller executes the intelligent power replenishment logic.

3. The new energy heavy truck safety power-off system according to claim 1, characterized in that, It also includes a multi-in-one DC-DC input module, which is connected to the positive terminal of the battery and ground at its two ends, respectively, to convert the 600V high-voltage electricity of the vehicle's power battery into 27V low-voltage electricity to charge the battery.

4. The new energy heavy truck safe power-off system according to claim 1, characterized in that, A VCU fuse is provided between the first moving contact of the double-pole single-throw manual switch and the stationary contact of the key switch; A delayed power-off fuse is provided between the first moving contact of the double-pole single-throw manual switch and the stationary contact of the second power-off delay relay.

5. A method for safely powering down a new energy heavy-duty truck based on the new energy heavy-duty truck safe power-down system according to any one of claims 1 to 4, characterized in that, Includes the following steps: Turn the key switch to the ON position. When the key switch is closed, the manual switch is disconnected. When the conditions for the high-pressure process are met, the high-pressure process is executed. When the high-voltage process is completed, the VCU controller controls the power-down delay control terminal to continue outputting a low level until a certain set delay time is reached; The VCU controller stops outputting a low level, the power-down delay relay disconnects, and the vehicle stops drawing power from the battery.

6. The method for safely powering down a new energy heavy-duty truck according to claim 5, characterized in that, The specific conditions for the high-pressure process include: The VCU controller's ON position wake-up signal disappears for more than 1 second, and the current vehicle speed is determined to be less than 5 km / h.

7. The method for safely powering down a new energy heavy-duty truck according to claim 5, characterized in that, When the conditions for a high-pressure process are not met: If the A+ charging wake-up signal or intelligent power replenishment signal of the VCU controller is valid, the VCU controller will not execute the high voltage process. If the charging gun is plugged in, the A+ charging wake-up signal is continuously output to wake up the VCU controller. The VCU controller determines the current key switch position. If the key switch is not in the ON position and the smart charging signal is invalid, the VCU controller executes the charging high voltage logic. If the battery voltage is below 24.5V, the intelligent power replenishment system will output an intelligent power replenishment signal to wake up the VCU controller. The VCU controller will determine the current key switch position. If the key switch is not in the ON position and the intelligent power replenishment signal is valid, the VCU controller will execute the intelligent power replenishment logic to increase or decrease the high voltage.

8. The method for safely powering down a new energy heavy-duty truck according to claim 6, characterized in that, The calculation of the current vehicle speed specifically includes: ； In the formula, V Current vehicle speed n The output shaft speed of the gearbox. r For the tire radius, i g The rear axle speed ratio, i 0 The main reducer transmission ratio.

9. The method for safely powering down a new energy heavy-duty truck according to claim 5, characterized in that, The VCU controller controls the power-down delay control terminal to continue outputting a low level until a certain set delay time is reached, specifically including: After the VCU controller is woken up, its power-down delay control terminal continuously outputs a low level; Eight seconds after the VCU controller wake-up signal disappears, its power-down delay control terminal stops outputting a low level.

10. The method for safely powering down a new energy heavy-duty truck according to claim 5, characterized in that, When the VCU controller stops outputting a low level, the power-down delay relay disconnects, and the vehicle stops drawing power from the battery. Specifically, this includes: The second power-down delay relay coil is de-energized, and then the moving contact of the second power-down delay relay opens, de-energizing all high-voltage accessory relays and the first power-down delay relay coil. The coil of the first power-down delay relay is de-energized, and then the moving contact of the first power-down delay relay opens, stopping the vehicle from drawing power from the battery.

Images