Control method for lithium battery pack of electric forklift

Abstract

The invention discloses a control method for a lithium battery pack of an electric forklift, which comprises the following steps: (1) when an REMA plug-in is connected with a charger, a state recognition end of a BMS recognizes 12V through a coil of a contactor J1 and a diode D2, and the state is in a charging state at the moment; (2) when the REMA plug-in is connected with the whole vehicle, the state S is connected with 12V-, the BMS detects a low level, and at the moment, the REMA plug-in is in a discharging state; (3) a switch S1 is closed, a self-reset switch K1 is pressed, a triode Q1 is subjected to voltage division through a resistor R1 and a resistor R2, appropriate voltage is taken from the resistor R1, the S pole and the D pole of the triode Q1 are conducted, the EN end of DCDC obtains high level, DCDC works, the S pole and the D pole of the triode Q1 are in short circuit, at the moment, the self-reset switch K1 is loosened, the EN end of DCDC continues high level, and power-on of the battery pack BMS is completed; and (4) the REMA plug-in is connected with the charger, the state S is suspended, the BMS detects that the REMA plug-in is in a charging state, after a message of the charger is received, the charging driving end of the BMS drives the J2 to be closed, then the coil of the contactor J1 is electrified, the J1 of the DCDC is closed, the positive electrode of the battery pack outputs voltage to the charger, and the battery pack enters a normal charging state.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium battery charging, and particularly to a control method for a lithium battery pack of an electric forklift. Background Art

[0002] During the charging and discharging processes of existing lithium battery packs of electric forklifts, there are problems such as complex control, low efficiency, and insufficient safety. Especially in the power-on and power-off control process, existing methods often cannot achieve fast and stable switching, and lack an effective delayed power-off mechanism, resulting in a shortened service life of the battery pack and even potential safety hazards.

[0003] Therefore, a control method for a lithium battery pack of an electric forklift is provided. Summary of the Invention

[0004] The purpose of the present invention is to provide a control method for a lithium battery pack of an electric forklift to solve the problems raised in the above background art.

[0005] To achieve the above purpose, the present invention provides the following technical solutions:

[0006] A control method for a lithium battery pack of an electric forklift includes the following steps:

[0007] (1) When the REMA plug is connected to the charger, the status recognition terminal of the BMS recognizes 12V through the contactor J1 coil and the diode D2, and this is the charging state at this time;

[0008] (2) When the REMA plug is connected to the vehicle, the status S is connected to 12V-, and the BMS detects a low level, and this is the discharging state at this time;

[0009] (3) Close the switch S1, press the self-resetting switch K1 once. The triode Q1 is voltage-divided by the resistors R1 and R2, and an appropriate voltage is obtained across the resistor R1, causing the S pole and D pole of the triode Q1 to conduct. The EN terminal of the DCDC obtains a high level, and the DCDC works, short-circuiting the S pole and D pole of the triode Q1. At this time, release the self-resetting switch K1, and the EN terminal of the DCDC will continue to be at a high level, and the power-on of the battery pack BMS is completed;

[0010] (4) When the REMA plug is connected to the charger and the status S is suspended, and the BMS detects the charging state, after receiving the message from the charger, the charging drive terminal of the BMS drives J2 to close, and then the contactor J1 coil is energized, and J1 of the DCDC is closed, and the positive output voltage of the battery pack reaches the charger, entering the normal charging state;

[0011] (5) When the charging reaches the set voltage, the BMS controls the contactor J3 to disconnect, the DCDC stops output, the contactor J1 disconnects the output, and the BMS powers off to complete the charging;

[0012] (6) After the REMA plug-in is connected to the vehicle, close the switch S1, turn on the key switch K2 on the vehicle, the triode Q1 conducts, the DCDC outputs 12V, the contactor J1 is energized and attracted, the battery pack outputs voltage to the vehicle, and enters the normal discharge state;

[0013] (7) Turn off the key, the vehicle powers down at low voltage. When the BMS detects that the current is continuously less than the set value, through the internal timer, at this time the contactor J3 loses power, the EN terminal of the DCDC loses power, and the DCDC stops outputting, completing the delayed power-down.

[0014] Furthermore, in the step (1), when the REMA plug-in is connected to the charger, the state S is floating.

[0015] Furthermore, in the step (2), when closing the switch S1, the time for pressing the self-resetting switch K1 once is 1S.

[0016] Furthermore, in the step (3), the DCDC works, outputs 12V+ to supply power to the BMS. After the BMS works, the power supply drive end controls J3 to close, short-circuits the S pole and the D pole of the triode Q1. At this time, release the self-resetting switch K1, and the EN terminal of the DCDC will maintain a high level, and the battery pack BMS powers on successfully.

[0017] Furthermore, in the step (4), the positive pole of the battery pack outputs voltage to the charger. After the charger detects the battery pack voltage, it exchanges charging messages with the BMS, and the charger outputs the requested charging voltage and current, and enters the normal charging state.

[0018] Furthermore, in the step (6), the contactor J1 is energized and attracted, the battery pack outputs voltage to the vehicle, the BMS drives the contactor J3 to close, and the BMS sends a message to interact with the vehicle, and enters the normal discharge state.

[0019] Furthermore, in the step (7), through the internal timer, the power supply drive end is set to a low level every 5 minutes.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] 1. Automatically identify the charging and discharging states: Through the connection state of the REMA plug-in to the charger or the vehicle, the BMS can automatically identify whether the battery pack is currently in the charging state or the discharging state, without manual intervention, greatly simplifying the operation process, reducing the possibility of human misoperation, and improving the intelligent level of the system;

[0022] 2. Fast and stable power-on and power-off switching: Through reasonable circuit design and control logic, the present invention realizes fast and smooth switching of the battery pack between the charging and discharging states. Especially during the power-on and power-off processes, through the coordinated operation of the DCDC converter and the contactor, stable output of voltage and current is ensured, avoiding equipment damage or safety hazards caused by voltage fluctuations or current surges;

[0023] 3. Delayed power-off mechanism: During the discharging process, the present invention introduces a delayed power-off mechanism. When it is detected that the current continuously is less than the set value, the BMS will perform a detection every 5 minutes through an internal timer to ensure that after the vehicle's low-voltage power-off, the battery pack can complete the power-off process safely and smoothly. This mechanism not only extends the service life of the battery pack but also avoids equipment damage or data loss caused by sudden power-off;

[0024] 4. Improving the safety of the battery pack: Through the precise control and multiple protection mechanisms of the BMS, the present invention can effectively prevent safety hazards such as overcharging, over-discharging, and short-circuiting of the battery pack during the charging and discharging processes. Especially during the charging process, the BMS can real-time monitor parameters such as the voltage, current, and temperature of the battery pack to ensure that the charging process is carried out within a safe range;

[0025] 5. Extending the service life of the battery pack: Through reasonable power-on and power-off control processes and the delayed power-off mechanism, the present invention reduces the loss of the battery pack during frequent charging and discharging processes, extending the service life of the battery pack. At the same time, the precise control of the BMS also avoids the performance degradation of the battery pack caused by overcharging or over-discharging;

[0026] 6. Improving the reliability and stability of the system: Through the coordinated operation of multiple hardware such as the DCDC converter, contactor, and electronic components and the BMS software, the present invention ensures the reliability and stability of the battery pack under various working conditions. Whether during the charging or discharging process, the system can maintain stable voltage and current output to ensure the normal operation of the electric forklift;

[0027] 7. Simplifying the operation process: By automatically identifying the charging and discharging states, the present invention simplifies the operation process. Users only need to perform simple switch operations to complete the power-on and power-off control of the battery pack, without complex settings and adjustments, greatly reducing the usage threshold and enhancing the user experience. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic diagram of the circuit structure of the present invention;

[0029] Figure 2 is a schematic diagram of the plug-in interface structure of the present invention;

[0030] Figure 3 is a schematic diagram of the key switch structure of the present invention;

[0031] Figure 4 Schematic diagram of the charger end structure of the present invention. Detailed implementation manners

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0033] Embodiment 1:

[0034] Please refer to Figures 1-4 , the present invention provides a technical solution:

[0035] A control method for a lithium battery pack of an electric forklift, comprising the following steps:

[0036] (1) When the REMA plug is connected to the charger, the status recognition terminal of the BMS recognizes 12V through the contactor J1 coil and the diode D2, and this is the charging state at this time;

[0037] (2) When the REMA plug is connected to the whole vehicle, the status S is connected to 12V-, and the BMS detects a low level, and this is the discharging state at this time;

[0038] (3) Close the switch S1, press the self-resetting switch K1 once, the triode Q1 is divided by the resistors R1 and R2, and a suitable voltage is obtained on the resistor R1, so that the S pole and the D pole of the triode Q1 are conducted, the EN terminal of the DCDC gets a high level, the DCDC works, and the S pole and the D pole of the triode Q1 are short-circuited. At this time, release the self-resetting switch K1, and the EN terminal of the DCDC will continue to be at a high level, and the power-on of the battery pack BMS is completed;

[0039] (4) When the REMA plug is connected to the charger and the status S is suspended, the BMS detects the charging state. After receiving the message from the charger, the charging drive terminal of the BMS drives J2 to close, and then the contactor J1 coil is energized, J1 of the DCDC is closed, and the positive output voltage of the battery pack reaches the charger, entering the normal charging state;

[0040] (5) When the charging reaches the set voltage, the BMS controls the contactor J3 to disconnect, the DCDC stops output, the contactor J1 disconnects the output, and the BMS powers off to complete the charging;

[0041] (6) After the REMA plug is connected to the whole vehicle, close the switch S1, turn on the key switch K2 on the vehicle, the triode Q1 is conducted, the DCDC outputs 12V, the contactor J1 is energized and attracted, and the battery pack outputs voltage to the whole vehicle, entering the normal discharging state;

[0042] (7) Close the key, power off the vehicle's low-voltage system. When the BMS detects that the current remains less than the set value, through the internal timer, the contactor J3 loses power at this time, the EN terminal of the DCDC loses power, and the DCDC stops outputting, completing the delayed power-off.

[0043] In step (1), when the REMA plug is connected to the charger, the state S is floating.

[0044] In step (2), close the switch S1, and the time to press the self-resetting switch K1 once is 1S.

[0045] In step (3), the DCDC works and outputs 12V+ to supply power to the BMS. After the BMS works, the power supply drive terminal controls J3 to close, short-circuiting the S pole and D pole of the triode Q1. At this time, release the self-resetting switch K1, and the EN terminal of the DCDC will remain at a high level, and the battery pack BMS power-on is completed.

[0046] In step (4), the positive pole of the battery pack outputs voltage to the charger. After the charger detects the battery pack voltage, it exchanges charging messages with the BMS, and the charger outputs the requested charging voltage and current, entering the normal charging state.

[0047] In step (6), the contactor J1 is energized and closed, the battery pack outputs voltage to the vehicle, the BMS drives the contactor J3 to close, and the BMS sends messages to interact with the vehicle, entering the normal discharge state.

[0048] In step (7), through the internal timer, the power supply drive terminal is set to a low level every 5 minutes.

[0049] Working principle:

[0050] When the REMA plug is connected to the charger (state S is floating), the status recognition terminal of the BMS recognizes 12V through the J1 coil and D2, and this is the charging state at this time;

[0051] When the REMA plug is connected to the vehicle, the state S is connected to 12V-, and the BMS detects a low level, and this is the discharge state at this time;

[0052] Close switch S1, press the self-resetting switch K1 once (hold for 1S). Q1 is voltage-divided by R1 and R2, and an appropriate voltage is obtained across R1, causing the S and D poles of Q1 to conduct. The EN terminal of the DCDC gets a high level, and the DCDC starts working, outputting 12V+ to power the BMS. After the BMS starts working, the power supply drive terminal controls J3 to close, short-circuiting the S and D poles of Q1. At this time, release K1, and the EN terminal will remain at a high level, completing the power-on of the battery pack BMS. The REMA plug is connected to the charger, and the status S is left floating. The BMS detects it as the charging state. After receiving the message from the charger, the charging drive terminal of the BMS drives J2 to close, and then the J1 coil gets energized and J1 closes. The positive output voltage of the battery pack is sent to the charger. After the charger detects the battery pack voltage, it exchanges charging messages with the BMS, and the charger outputs the requested charging voltage and current, entering the normal charging state.

[0053] When the charging reaches the set voltage, the BMS controls J3 to disconnect, the DCDC stops outputting, J1 disconnects the output, and the BMS powers off, completing the charging.

[0054] After the REMA plug is connected to the vehicle, close switch S1, turn on the key switch K2 in the vehicle. Q1 conducts, the DCDC outputs 12V, J1 gets energized and closes. The battery pack outputs voltage to the vehicle, and the BMS drives J3 to close. The BMS sends messages to interact with the vehicle and enters the normal discharging state.

[0055] Turn off the key, and the vehicle powers off at low voltage. (Delay strategy) The BMS detects that the current continuously becomes less than the set value. Through the internal timer, it sets the power supply drive terminal to a low level every 5 minutes. At this time, J3 loses power, the EN terminal of the DCDC loses power, and the DCDC stops outputting, completing the delayed power-off.

[0056] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A control method for an electric forklift lithium battery pack, characterized in that: The following steps are involved: (1) When the REMA plug-in is connected to the charger, the state recognition terminal of the BMS recognizes 12V through the contactor J1 coil and the diode D2, and it is in the charging state at this time; (2) When the REMA plug-in is connected to the vehicle, state S is connected to 12V-, and the BMS detects a low level, which is the discharge state; (3) Close switch S1 and press the self-reset switch K1. The transistor Q1 is divided by resistors R1 and R2, and a suitable voltage is obtained on resistor R1, so that the S and D poles of the transistor Q1 are turned on, and the EN terminal of DCDC is high. DCDC works, short-circuiting the S and D poles of the transistor Q1. At this time, release the self-reset switch K1, and the EN terminal of DCDC will continue to be high. The battery pack BMS is powered on; (4) The REMA plug-in is connected to the charger, the state S is suspended, and the BMS detects that it is in the charging state. After receiving the message from the charger, the charging drive end of the BMS drives J2 to close, and then the contactor J1 coil is energized, the DCDC J1 is closed, and the positive electrode of the battery pack outputs voltage to the charger, entering the normal charging state; (5) When the charging reaches the set voltage, the BMS controls the contactor J3 to disconnect, the DCDC stops outputting, the contactor J1 disconnects the output, the BMS powers off, and the charging is completed; (6) After the REMA plug-in is connected to the vehicle, the switch S1 is closed, the key switch K2 on the vehicle is turned on, the transistor Q1 is turned on, the DCDC outputs 12V, the contactor J1 is energized and closed, the battery pack outputs voltage to the vehicle, and enters the normal discharge state; (7) Turn off the key, the vehicle is powered off at low voltage, and the BMS detects that the current is continuously less than the set value. Through the internal timer, the contactor J3 loses power, the EN terminal of the DCDC loses power, the DCDC stops outputting, and the delayed power-off is completed.

2. The control method of an electric forklift lithium battery pack according to claim 1, characterized in that: In the step (1), when the REMA plug-in is connected to the charger, the state S is suspended.

3. The control method of an electric forklift lithium battery pack according to claim 1, characterized in that: In step (2), the switch S1 is closed and the time for pressing the self-resetting switch K1 is 1 second.

4. The control method of a lithium battery pack for an electric forklift according to claim 1, characterized in that: In step (3), DCDC works and outputs 12V+ to power the BMS. After the BMS works, the power supply drive end controls J3 to close, so that the S pole and the D pole of the transistor Q1 are short-circuited. At this time, the self-reset switch K1 is released, the EN terminal of the DCDC will continue to be at a high level, and the battery pack BMS is powered on.

5. The control method of an electric forklift lithium battery pack according to claim 1, characterized in that: In step (4), the positive electrode of the battery pack outputs voltage to the charger. After the charger detects the battery pack voltage, it interacts with the BMS via charging messages. The charger outputs the requested charging voltage and current and enters a normal charging state.

6. The control method of an electric forklift lithium battery pack according to claim 1, characterized in that: In step (6), the contactor J1 is energized and closed, the battery pack outputs voltage to the vehicle, the BMS drives the contactor J3 to close, and the BMS sends a message to interact with the vehicle, entering a normal discharge state.

7. The control method of an electric forklift lithium battery pack according to claim 1, characterized in that: In the step (7), the power supply driving end is set to a low level every 5 minutes through an internal timer.

Images