Method for managing electric quantity of low-voltage battery module of new energy vehicle

Abstract

The invention relates to a method for managing the electric quantity of a low-voltage battery module of a new energy vehicle, which belongs to the technical field of vehicle-mounted batteries and comprises the following steps of: 1, judging the mode of the new energy vehicle, and determining whether a main charging and discharging loop supplies power to an external load and / or charges the low-voltage battery module; 2, in the parking and locking mode, the SOC threshold value of the low-voltage battery module is judged, and whether power is supplied to an external load through a small-current discharging loop or not is determined; 3, trying to wake up, and deciding to enter the step 4 or the step 5; 4, the main charging and discharging loop charges the low-voltage battery module; 5, the low-voltage battery module enters a power locking state and is switched to a deep sleep mode; 6, after an external wake-up signal is input, the low-voltage battery module is charged, the current is monitored, and whether charging is maintained or the step 7 is executed is determined; and 7, continuing to try to wake up, if the electric quantity management module responds, returning to the step 6, otherwise, continuing to maintain the deep sleep mode. It can be guaranteed that the new energy vehicle runs more safely.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle-mounted batteries, and particularly relates to a method for managing the power of a low-voltage battery module in a new energy vehicle. Background Art

[0002] The low-voltage battery module has always played a very important role in automobiles. It not only supplies power to core electrical equipment such as starters and ignition systems when the engine starts, but also needs to supply power to various electrical equipment in the vehicle when the engine is stopped or running at a low speed. Currently, with the development of new energy vehicles, the low-voltage battery module in new energy vehicles has gradually evolved to mainly supply power to control modules such as the PKE / RKE system and anti-theft modules when the vehicle is parked and locked. Due to the large starting current output of new energy vehicles being different from that of traditional fuel vehicles, the power requirement for the low-voltage battery module is relatively small. Therefore, the low-voltage battery module in new energy vehicles generally has a small capacity. In addition, when the vehicle is parked and locked, the low-voltage battery still needs to supply power to other modules in the vehicle. Over time, it is very easy to occur over-discharge. Over-discharge may cause damage to the electrode active material and loss of reaction ability, causing irreversible damage to the battery module.

[0003] Therefore, in order to avoid deep discharge of the low-voltage battery module, it is necessary to manage its power to ensure the safer and more effective operation of new energy vehicles. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for managing the power of a low-voltage battery module in a new energy vehicle to avoid deep discharge of the low-voltage battery module and ensure the safer operation of new energy vehicles in view of the problems existing in the prior art.

[0005] The technical solution is as follows:

[0006] A method for managing the power of a low-voltage battery module in a new energy vehicle, in which a main charge and discharge circuit and a small current discharge circuit controlled by a power management module to be turned on or off are provided between the low-voltage battery module and the load, and the following steps are executed:

[0007] Step 1: Determine whether the new energy vehicle is in an operating mode or a parked and locked mode. If the new energy vehicle is in an operating mode, the power management module controls the main charge and discharge circuit to supply power to an external load and / or charge the low-voltage battery module, otherwise enter the next step;

[0008] Step 2: When the new energy vehicle is in a parked and locked mode, detect whether the SOC of the low-voltage battery module is lower than the charging threshold or the power locking threshold, where the charging threshold is greater than the power locking threshold. If the SOC of the low-voltage battery module is not lower than the charging threshold, supply power to the external load through the small current discharge circuit. If the SOC of the low-voltage battery module is lower than the charging threshold but higher than the power locking threshold, enter Step 3. If the SOC of the low-voltage battery module is lower than the power locking threshold, enter Step 5;

[0009] Step 3: The low-voltage battery module attempts to wake up the new energy vehicle. If the wake-up is successful, go to Step 4; if the wake-up fails, go to Step 5;

[0010] Step 4: The low-voltage battery module sends a request for charging instruction to the power management module, and the main charging and discharging circuit charges the low-voltage battery module;

[0011] Step 5: The low-voltage battery module enters the power-locking state and switches to the deep sleep mode. The power management module controls that neither the main charging and discharging circuit nor the small current discharging circuit outputs externally and enters Step 6;

[0012] Step 6: After an external wake-up signal is input, the power management module closes the main charging and discharging circuit to charge the low-voltage battery module, and monitors the current of the low-voltage battery module after a certain time to see if it is greater than the charging judgment threshold. If it is greater than the charging judgment threshold, the main charging and discharging circuit continues to charge the low-voltage battery module; if it is not greater than the charging judgment threshold, go to Step 7;

[0013] Step 7: Continue to attempt to wake up the new energy vehicle. If the power management module responds, return to Step 6; if there is no response, control the low-voltage battery module to continue to maintain the deep sleep mode.

[0014] Further, the power management module includes an MCU and an AFE chip (analog front-end chip). The AFE chip is responsible for detecting the voltage and current of each battery in the low-voltage battery module. The MCU controls the closing and opening of the main charging and discharging circuit and the small current discharging path, and calculates the real-time SOC value of the low-voltage battery module according to the data detected by the AFE chip.

[0015] Further, the main charging and discharging circuit includes MOS transistors, sampling resistors and relays. The MOS transistors are connected to the control signal and the driving power supply. The relays are respectively connected to the external load, the low-voltage battery module and the output of the MOS transistors. The output of the MOS transistors completes the feedback inspection of the control signal through the sampling resistor. After passing through the MOS transistors, the control signal controls the on-off of the relays, and further controls the external load to charge the low-voltage battery module through the main charging and discharging circuit.

[0016] Further, the small current discharging circuit includes a current sensor, an overcurrent protector, a sampling resistor, MOS transistors and a driving chip; among them, the current sensor and the MOS transistors are connected in series between the external load and the low-voltage battery module; there are two MOS transistors, whose drains are connected together, the gates are connected to the driving chip, and the sources are respectively connected to the current sensor and the low-voltage battery module; the current sensor controls whether the control signal is connected to the driving chip through the overcurrent protector; the control signal controls the on-off of the MOS transistors through the driving chip, and further controls the external load to charge the low-voltage battery module through the small current discharging circuit, and completes the feedback inspection through the sampling resistor.

[0017] Further, when the main charge and discharge circuit or the small current discharge circuit is working, it does not accept the input of external wake-up signals.

[0018] Further, in step 6, the external wake-up signal includes a power supply connection wake-up signal or a hardware switch signal.

[0019] Further, the certain time in step 6 is 1 - 5 minutes.

[0020] Beneficial effects:

[0021] 1) By using the MCU and the AFE chip to judge the condition of the new energy vehicle and combining with the SOC value to control the management of charging and discharging, the present invention can effectively avoid the irreversible damage to the low-voltage battery module caused by the deep discharge of the low-voltage battery module, and ensure the safer operation of the new energy vehicle.

[0022] 2) The circuit is simple and the management effect is good, which can significantly improve the service life of the low-voltage battery module. Description of the drawings

[0023] Figure 1 is the flowchart of the method of the present invention;

[0024] Figure 2 is the logic circuit diagram of the present invention;

[0025] Figure 3 is the logic circuit diagram of the main charge and discharge circuit of the present invention;

[0026] Figure 4 is the logic circuit diagram of the small current discharge circuit of the present invention. Detailed implementation manners

[0027] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. The orientation or positional relationships indicated by the terms "upper", "lower", "front", "rear", "left", "right", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0028] As Figure 1 shown, a method for managing the power of a low-voltage battery module of a new energy vehicle is provided. A main charge and discharge circuit and a small current discharge circuit controlled to be conducted or cut off by a power management module are arranged between the low-voltage battery module and the load, and the following steps are executed:

[0029] Step 1: Determine whether the new energy vehicle is in the operating mode or the parked and locked mode. If the new energy vehicle is in the operating mode, the power management module controls the main charge and discharge circuit to supply power to the external load and / or charge the low-voltage battery module. Otherwise, proceed to the next step;

[0030] Step 2: When the new energy vehicle is in the parked and locked mode, detect whether the SOC of the low-voltage battery module is lower than the replenishment threshold or the power locking threshold, where the replenishment threshold is greater than the power locking threshold. If the SOC of the low-voltage battery module is not lower than the replenishment threshold, supply power to the external load through the small current discharge circuit. If the SOC of the low-voltage battery module is lower than the replenishment threshold but higher than the power locking threshold, proceed to Step 3. If the SOC of the low-voltage battery module is lower than the power locking threshold, proceed to Step 5;

[0031] Step 3: The low-voltage battery module attempts to wake up the new energy vehicle. If the wake-up is successful, proceed to Step 4. If the wake-up fails, proceed to Step 5;

[0032] Step 4: The low-voltage battery module sends a request for replenishment instruction to the power management module, and the main charge and discharge circuit replenishes the low-voltage battery module;

[0033] Step 5: The low-voltage battery module enters the power locking state and switches to the deep sleep mode. The power management module controls both the main charge and discharge circuit and the small current discharge circuit not to output externally and proceeds to Step 6;

[0034] Step 6: After an external wake-up signal including a jump-start wake-up signal or a hardware switch signal is input, the power management module closes the main charge and discharge circuit to charge the low-voltage battery module, and monitors the current of the low-voltage battery module after 1 - 5 minutes to see if it is greater than the charging judgment threshold. If it is greater than the charging judgment threshold, maintain the main charge and discharge circuit to charge the low-voltage battery module; if it is not greater than the charging judgment threshold, proceed to Step 7;

[0035] Step 7: Continue to attempt to wake up the new energy vehicle. If the power management module responds, return to Step 6. If there is no response, control the low-voltage battery module to continue to maintain the deep sleep mode.

[0036] The power management module includes an MCU and an AFE chip. The AFE chip is responsible for detecting the voltage and current of each battery in the low-voltage battery module. The MCU controls the closing and opening of the main charge and discharge circuit and the small current discharge path, and calculates the real-time SOC value of the low-voltage battery module based on the data detected by the AFE chip.

[0037] The main charge and discharge circuit includes a MOS transistor, a sampling resistor, and a relay. The MOS transistor is connected to a control signal and a driving power supply. The relay is respectively connected to an external load, a low-voltage battery module, and the output of the MOS transistor. The output of the MOS transistor passes through the sampling resistor to complete the feedback inspection of the control signal. After passing through the MOS transistor, the control signal controls the on / off of the relay, thereby controlling the external load to charge the low-voltage battery module through the main charge and discharge circuit.

[0038] The small current discharge circuit includes a current sensor, an overcurrent protector, a sampling resistor, a MOS transistor, and a driving chip. Among them, the current sensor and the MOS transistor are connected in series between the external load and the low-voltage battery module. There are two MOS transistors, whose drains are connected together, the gates are connected to the driving chip, and the sources are respectively connected to the current sensor and the low-voltage battery module. The current sensor controls whether the control signal is connected to the driving chip through the overcurrent protector. The control signal controls the on / off of the MOS transistor through the driving chip, thereby controlling the external load to charge the low-voltage battery module through the small current discharge circuit, and completing the feedback inspection through the sampling resistor.

[0039] When the main charge and discharge circuit or the small current discharge circuit is working, it does not accept the input of an external wake-up signal.

[0040] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the principle and spirit of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for power management of a low-voltage battery module of a new energy vehicle, wherein a main charge and discharge circuit and a low-current discharge circuit controlled to be turned on or off by a power management module are arranged between the low-voltage battery module and the load, and the following steps are performed: Step 1: Determine whether the new energy vehicle is in the running mode or the parking and locking mode. If the new energy vehicle is in the running mode, the power management module controls the main charging and discharging circuit to supply power to the external load and / or charge the low-voltage battery module. Otherwise, proceed to the next step. Step 2: When the new energy vehicle is in the parking and locking mode, detect whether the SOC of the low-voltage battery module is lower than the charging threshold or the locking threshold, where the charging threshold is greater than the locking threshold. If the SOC of the low-voltage battery module is not lower than the charging threshold, power is supplied to the external load through a small current discharge circuit. If the SOC of the low-voltage battery module is lower than the charging threshold but higher than the locking threshold, proceed to step 3. If the SOC of the low-voltage battery module is lower than the locking threshold, proceed to step 5. Step 3: The low-voltage battery module attempts to wake up the new energy vehicle. If the wake-up succeeds, it proceeds to step 4. If the wake-up fails, it proceeds to step 5. Step 4: The low-voltage battery module sends a request for power replenishment to the power management module, and the main charge and discharge circuit replenishes power to the low-voltage battery module; Step 5: The low-voltage battery module enters the power-locking state and switches to the deep sleep mode. The power management module controls the main charge and discharge circuit and the low-current discharge circuit to not output externally and enters step 6; Step 6: After an external wake-up signal is input, the power management module closes the main charge and discharge loop to charge the low-voltage battery module, and monitors the current of the low-voltage battery module after a certain period of time to see if it is greater than the charging judgment threshold. If it is greater than the charging judgment threshold, the main charge and discharge loop is maintained to charge the low-voltage battery module; if it is not greater than the charging judgment threshold, go to step 7; Step 7: Continue to try to wake up the new energy vehicle. If the power management module responds, return to step 6. If there is no response, control the low-voltage battery module to continue to maintain deep sleep mode.

2. The method for managing the power of a low-voltage battery module for a new energy vehicle according to claim 1, characterized in that: The power management module includes an MCU and an AFE chip. The AFE chip is responsible for detecting the voltage and current of each battery in the low-voltage battery module. The MCU controls the closing and opening of the main charging and discharging circuit and the small current discharge path, and calculates the real-time SOC value of the low-voltage battery module based on the data detected by the AFE chip.

3. The method for managing the power of a low-voltage battery module for a new energy vehicle according to claim 1, characterized in that: The main charge and discharge circuit includes a MOS tube, a sampling resistor and a relay. The MOS tube is connected to the control signal and the driving power supply. The relay is respectively connected to the external load, the low-voltage battery module and the MOS tube output. The MOS tube output completes the return check of the control signal through the sampling resistor. The control signal controls the on and off of the relay after passing through the MOS tube, and then controls the external load to charge the low-voltage battery module through the main charge and discharge circuit.

4. The method for managing power of a low-voltage battery module for a new energy vehicle according to claim 1, characterized in that: The small current discharge loop comprises a current sensor, an overcurrent protector, a sampling resistor, a MOS tube and a driving chip; wherein the current sensor and the MOS tube are connected in series between an external load and a low-voltage battery module; there are two MOS tubes, whose drains are connected together, whose gates are connected to the driving chip, and whose sources are respectively connected to the current sensor and the low-voltage battery module; the current sensor controls whether the control signal is connected to the driving chip through the overcurrent protector; the control signal controls the on-off of the MOS tube through the driving chip, thereby controlling the external load to charge the low-voltage battery module through the small current discharge loop, and completing the back-check through the sampling resistor.

5. The method for managing power of a low-voltage battery module for a new energy vehicle according to claim 1, characterized in that: When the main charge-discharge circuit or the small current discharge circuit is working, no external wake-up signal input is accepted.

6. The method for managing power of a low-voltage battery module for a new energy vehicle according to claim 1, characterized in that: The external wake-up signal in step 6 includes a power-on wake-up signal or a hardware switch signal.

7. The method for managing power of a low-voltage battery module for a new energy vehicle according to claim 1, characterized in that: The certain time mentioned in step 6 is 1 to 5 minutes.

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