Power-on and power-off control circuit of high-voltage lithium battery forklift

Abstract

The utility model discloses a power-on and power-off control circuit of a high-voltage lithium battery forklift. The power-on and power-off control circuit comprises a whole vehicle key switch (9), a whole vehicle emergency stop switch (10), a first relay (6), a second relay (7) and a third relay (8). A first relay coil is controlled by a whole vehicle key switch and a whole vehicle emergency stop switch, a common end of a second relay is connected with one end of a third relay coil, the other end of the third relay coil is connected with an F3 end point of a whole vehicle controller VCU (3), and a normally open end point of the second relay is connected with a positive electrode of a starting battery (2). A normally-closed end point of the second relay is connected with a positive electrode of a charging input end of the high-voltage lithium battery system (1), a common end of the third relay is connected with a positive electrode of a power supply output end of the high-voltage lithium battery system, and a normally-open end point of the third relay is connected with an instrument panel (11). According to the power-on and power-off control circuit, the forklift can unload high voltage to safe voltage after a key is closed.

Description

Technical Field

[0001] The utility model relates to a forklift electrical control technology, in particular to a high-voltage lithium battery forklift power-on and power-off control circuit. Background Art

[0002] At present, the power batteries used in electric forklifts mainly have two types: lead-acid batteries and lithium-ion batteries. Lithium-ion batteries are further divided into low-voltage lithium batteries (systems below 100V) and high-voltage lithium batteries. Among them, high-voltage lithium batteries have been used as the preferred power batteries for electric forklifts by forklift enterprises due to their high charging efficiency.

[0003] The current problem lies in:

[0004] If a high-voltage lithium battery is used as the power battery of an electric forklift, when the start key of the electric forklift is turned off, the high-voltage relay will be quickly cut off to prevent electric shock accidents. However, even if the high-voltage relay is disconnected, due to the existence of the bus wire capacitance of the motor controller, there is still a certain amount of electricity remaining on the motor controller bus. If not noticed, it will still cause harm to the vehicle, especially the driver. Therefore, reasonable high-voltage lithium battery power-off control is particularly important. Summary of the Invention

[0005] The purpose of the utility model is to provide a high-voltage lithium battery forklift power-on and power-off control circuit, which can unload the high voltage in the whole vehicle to a safe voltage after the key is turned off.

[0006] In order to achieve the above technical purpose, the utility model adopts the following technical solutions:

[0007] A high-voltage lithium battery forklift power-on and power-off control circuit. The forklift is an electric forklift, and a high-voltage lithium battery system, a starting battery, a vehicle controller VCU, a motor controller MCU, a drive motor, an instrument panel, and a DCDC converter are arranged in the forklift and connected together through electrical lines. The power-on and power-off control circuit includes a vehicle key switch, a vehicle emergency stop switch, a first relay, a second relay, and a third relay. The coil of the first relay is controlled by the vehicle key switch and the vehicle emergency stop switch. The common terminal of the first relay is connected to the positive pole of the starting battery. The normally open endpoint of the first relay is connected to the positive pole of the power input port of the motor controller MCU. One end of the coil of the second relay is connected to the normally open endpoint of the first relay, and the other end of the coil of the second relay is connected to the negative pole of the power input port of the motor controller MCU. The common terminal of the second relay is connected to one end of the coil of the third relay, and the other end of the coil of the third relay is connected to the F3 endpoint of the vehicle controller VCU. The normally open endpoint of the second relay is connected to the positive pole of the starting battery, and the normally closed endpoint of the second relay is connected to the positive pole of the charging input end of the high-voltage lithium battery system. The common terminal of the third relay is connected to the positive pole of the power supply output end of the high-voltage lithium battery system, and the normally open endpoint of the third relay is connected to the instrument panel.

[0008] Further, the first relay is a power-off delay type relay.

[0009] Further, the first relay is used to control the electrical system of the electric forklift to connect to the high-voltage lithium battery system; the second relay is used to connect the starting battery to the coil of the third relay to provide conditions for the activation of the third relay; the third relay is used to transfer power to the instrument panel to make the instrument panel work normally and display the working state of the electric forklift.

[0010] Further, the three-phase terminal of the motor controller MCU is connected to the drive motor, and the input end of the motor controller MCU is connected to the high-voltage lithium battery system.

[0011] The beneficial effects of the power-on and power-off control circuit of the present utility model compared with the prior art are as follows:

[0012] In the power-on and power-off control circuit of the present utility model, the first relay is a power-off delay type relay. When the forklift is powered off, the first relay is delayed to disconnect. During the delay period, the vehicle controller VCU still continues to work, the instrument panel is normally lit, and the residual voltage on the bus of the motor controller MCU is discharged to below the safe voltage through the DCDC converter. After the discharge is completed, the high-voltage lithium battery system is turned off, thus avoiding the harm caused by the residual power on the bus of the motor controller MCU to the vehicle and the driver and ensuring the safety of the equipment and personnel. Description of the Drawings

[0013] Figure 1This is the electrical schematic diagram of the power-on and power-off control circuit for the high-voltage lithium-ion forklift of the present utility model. Detailed implementation manners

[0014] The following uses specific embodiments to further illustrate the present utility model:

[0015] This implementation manner provides a power-on and power-off control circuit for a high-voltage lithium-ion forklift. This power-on and power-off control circuit can unload the high voltage in the whole vehicle to a safe voltage after the key is turned off.

[0016] Refer to Figure 1 , in the electric forklift involved in this implementation manner, there are currently a high-voltage lithium battery system 1, a starting battery 2, a vehicle controller VCU3, a motor controller MCU4, a drive motor 5, an instrument panel 11, and a DCDC converter 12.

[0017] The high-voltage lithium battery system 1 is used as the main power source of the electric forklift to provide the required high-voltage electrical energy for the whole vehicle to work.

[0018] The starting battery 2 is used to provide initial electrical energy for the whole vehicle at startup to wake up the vehicle controller VCU3 and the high-voltage lithium battery system 1.

[0019] The vehicle controller VCU3 is used as the core of the whole vehicle control of the electric forklift and is responsible for the comprehensive control of the running state of the whole vehicle.

[0020] The motor controller MCU4 is used to control the operation of the drive motor 5, adjust parameters such as the speed and torque of the drive motor 5 according to the instructions of the vehicle controller VCU3, and achieve precise control of the electric forklift.

[0021] The three-phase terminals of the motor controller MCU4 are connected to the drive motor 5, and the input terminal of the motor controller MCU4 is connected to the high-voltage lithium battery system 1.

[0022] The drive motor 5 is used to output driving force to drive the electric forklift to travel.

[0023] The instrument panel 11 is used to display the running state of the electric forklift.

[0024] The DCDC converter 12 is used to convert the high-voltage direct current output by the high-voltage lithium battery system 1 into low-voltage direct current for some on-vehicle electronic devices and auxiliary systems, such as the starting battery 2 and other low-voltage devices, which require low-voltage power supply to work properly.

[0025] The high-voltage lithium battery system 1 provides conventional driving power for the motor controller MCU4, the DCDC converter 12, and the vehicle controller VCU3. The output terminal of the DCDC converter 12 is connected to the starting battery 2, and the input terminal of the DCDC converter 12 is connected to the high-voltage lithium battery system 1.

[0026] The output voltage of the high-voltage lithium battery system 1 is divided into two paths. One path is input to the motor controller MCU4, and after being inverted by the motor controller MCU4, it becomes three-phase alternating current to control the operation of the drive motor 5. The other path is input to the DCDC converter 12, which converts the high-voltage electricity output from the high-voltage lithium battery system 1 into low voltage to charge the starting battery 2.

[0027] In summary, the above-mentioned high-voltage lithium battery system 1, starting battery 2, vehicle controller VCU3, motor controller MCU4, drive motor 5, instrument panel 11, and DCDC converter 12 are connected together through electrical circuits to achieve conventional electrical functions, which are common knowledge well-known to those skilled in the art.

[0028] See Figure 1 , the power-on and power-off control circuit of this embodiment includes two switches and three relays.

[0029] The two switches are respectively the vehicle key switch 9 and the vehicle emergency stop switch 10; the three relays are respectively the first relay 6, the second relay 7, and the third relay 8.

[0030] The vehicle key switch 9 is used to start or close the vehicle power supply and control the start and stop of the electric forklift.

[0031] The vehicle emergency stop switch 10 is used to provide an emergency stop function, which is used to quickly cut off the power supply in case of an emergency to ensure safety.

[0032] The first relay 6 is used to control the entire electrical system of the electric forklift to connect to the high-voltage lithium battery system 1; in this embodiment, the first relay 6 is a power-off delay type relay. In this way, when the coil of the first relay 6 loses power, the contacts of the first relay 6 will not jump immediately.

[0033] The second relay 7 is used to connect the power supply of the 12V starting battery 2 to the coil of the third relay 8, thereby providing conditions for the activation of the third relay 8.

[0034] The third relay 8 is used to be powered on and work after the vehicle controller VCU3 self-checks without faults, and transmit the power supply to the instrument panel 11 to make the instrument panel 11 work normally and display the working status of the electric forklift. At the same time, the activation of the third relay 8 also indicates that the vehicle controller VCU3 is ready to receive the start key signal and start the electric forklift.

[0035] Specifically,

[0036] The vehicle key switch 9 and the vehicle emergency stop switch 10 are connected in series and then connected between the coil of the first relay 6 and the high-voltage lithium battery system 1. In this way, the coil of the first relay 6 is controlled by the vehicle key switch 9 and the vehicle emergency stop switch 10. When the vehicle key switch 9 and the vehicle emergency stop switch 10 are both closed, the coil of the first relay 6 will be powered on, thereby connecting the entire electrical system to the high-voltage lithium battery system 1.

[0037] For the first relay 6, the common terminal of the first relay 6 is connected to the positive pole of the starting battery 2, the normally open endpoint of the first relay 6 is connected to the positive pole of the power input port of the motor controller MCU4, and the normally closed endpoint of the first relay 6 is left floating.

[0038] For the second relay 7, one end of the coil of the second relay 7 is connected to the normally open endpoint of the first relay 6, the other end of the coil of the second relay 7 is connected to the negative pole of the power input port of the motor controller MCU4, and is also connected to the negative pole of the starting battery 2. The common terminal of the second relay 7 is connected to one end of the coil of the third relay 8, the other end of the coil of the third relay 8 is connected to the F3 endpoint of the vehicle controller VCU3. The normally open endpoint of the second relay 7 is connected to the positive pole of the starting battery 2, and the normally closed endpoint of the second relay 7 is connected to the positive pole of the charging input end of the high-voltage lithium battery system 1.

[0039] For the third relay 8, the common terminal of the third relay 8 is connected to the positive pole of the power supply output end of the high-voltage lithium battery system 1, the normally open endpoint of the third relay 8 is connected to the instrument panel 11, and the normally closed endpoint of the third relay 8 is left floating.

[0040] The power-on and power-off control circuit of this embodiment works as follows:

[0041] When the vehicle emergency stop switch 10 and the vehicle key switch 9 are closed, the first relay 6 is powered on and works, and at the same time the second relay 7 is also powered on and works. After the first relay 6 is powered on, the starting battery 2 provides a 12V auxiliary power supply to the motor controller MCU4.

[0042] One end of the contact of the second relay 7 is connected to the starting battery 2, and the other end is connected to the positive pole of the coil of the third relay 8. The negative pole of the coil of the third relay 8 is connected to the F3 terminal of the vehicle controller VCU3. When the vehicle controller VCU3 self-checks without faults, the F3 terminal of the vehicle controller VCU3 will output a low-level signal to the negative pole of the coil of the third relay 8, creating a potential difference between the positive and negative poles of the coil of the third relay 8, and the third relay 8 is energized to work. After the coil of the third relay 8 is energized, the instrument panel 11 works. After the vehicle controller VCU3 receives the wake-up signal and the key signal, the vehicle controller VCU3 self-checks, wakes up the BMS by the vehicle controller VCU3, the BMS wakes up and conducts self-check, and closes the high-voltage discharge relay inside the high-voltage lithium battery system 1 after the self-check is fault-free. The positive and negative poles of the high-voltage lithium battery system 1 are respectively connected to the DCDC converter 12 and the motor controller MCU4. The high-voltage lithium battery system 1 charges the internal capacitor of the motor controller MCU4.

[0043] When the vehicle controller VCU3 self-checks without problems, it wakes up the DCDC converter 12. The DCDC converter 12 will convert the high voltage into low voltage to charge the starting battery 2.

[0044] After the vehicle key switch 9 or the vehicle emergency stop switch 10 is turned off, since the first relay 6 is a power-off delay type, the vehicle controller VCU3 is still in the wake-up mode. At this time, the vehicle controller VCU3 sends a high-voltage power-down command to the BMS through the E1 port, and the high-voltage discharge relay inside the high-voltage lithium battery system 1 disconnects. Since there is still high voltage on the bus of the motor controller MCU4, the vehicle controller VCU3 will send a charging command to the DCDC converter 12 to convert the high voltage into low voltage. The high voltage of the motor controller MCU4 and the high-voltage input terminal of the DCDC converter 12 form a discharge circuit to unload the high voltage to a safe voltage.

[0045] After the key is turned off, when the first relay 6 exceeds the set delay time, the contact of the first relay 6 disconnects, the vehicle controller VCU3 loses power, and at the same time the instrument panel 11 also goes out.

[0046] In the power-on and power-off control circuit of this embodiment, the first relay 6 is a power-off delay type relay, and the delay is 10 to 15 seconds. After the vehicle key switch 9 or the vehicle emergency stop switch 10 is turned off, the first relay 6 disconnects with a delay. During the delay period, the vehicle controller VCU3 still continues to work. At this time, the instrument panel 11 is normally lit, and the residual voltage on the bus of the motor controller MCU4 is discharged to below the safe voltage through the DCDC converter 12. After the discharge is completed, the high-voltage lithium battery system 1 goes out, thus avoiding the situation of "the residual power on the bus of the motor controller MCU4 causing harm to the vehicle and the driver", and ensuring the safety of equipment and personnel.

[0047] The above are only the preferred embodiments of the present utility model and are not intended to limit the protection scope of the present utility model. Therefore, any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A power-on and power-off control circuit for a high-voltage lithium battery forklift, wherein the forklift is an electric forklift, and the forklift is provided with a high-voltage lithium battery system (1), a starter battery (2), a vehicle controller VCU (3), a motor controller MCU (4), a drive motor (5), an instrument panel (11) and a DCDC converter (12) connected together through an electrical circuit; Features: The power on and off control circuit comprises a vehicle key switch (9), a vehicle emergency stop switch (10), a first relay (6), a second relay (7) and a third relay (8); the coil of the first relay (6) is controlled by the vehicle key switch (9) and the vehicle emergency stop switch (10), the common end of the first relay (6) is connected to the positive electrode of the starting battery (2), the normally open end of the first relay (6) is connected to the positive electrode of the power input port of the motor controller MCU (4), one end of the coil of the second relay (7) is connected to the normally open end of the first relay (6), and the other end of the coil of the second relay (7) is connected to the motor. The negative pole of the power input port of the controller MCU (4) is connected, the common end of the second relay (7) is connected to one end of the coil of the third relay (8), the other end of the coil of the third relay (8) is connected to the F3 terminal of the vehicle controller VCU (3), the normally open terminal of the second relay (7) is connected to the positive pole of the starter battery (2), the normally closed terminal of the second relay (7) is connected to the positive pole of the charging input terminal of the high-voltage lithium battery system (1), the common end of the third relay (8) is connected to the positive pole of the power supply output terminal of the high-voltage lithium battery system (1), and the normally open terminal of the third relay (8) is connected to the instrument panel (11).

2. According to the high-voltage lithium battery forklift power-on and power-off control circuit of claim 1, it is characterized by: The first relay (6) is a power-off delay type relay.

3. According to claim 1, the power-on and power-off control circuit of the high-voltage lithium battery forklift is characterized in that: The first relay (6) is used to control the electrical system of the electric forklift to connect to the high-voltage lithium battery system (1); the second relay (7) is used to connect the starting battery (2) to the coil of the third relay (8), thereby providing conditions for the activation of the third relay (8); the third relay (8) is used to transfer power to the instrument panel (11), so that the instrument panel (11) can work normally and display the working status of the electric forklift.

4. According to claim 1, the power-on and power-off control circuit of the high-voltage lithium battery forklift is characterized in that: The three-phase end of the motor controller MCU (4) is connected to the drive motor (5), and the input end of the motor controller MCU (4) is connected to the high-voltage lithium battery system (1).

Images