A novel overdischarge compensation method and test method

Abstract

The application discloses a novel battery over-discharge compensation method, which comprises two modes. In the first mode, a more serious fault occurs, but the all-in-one machine can still be powered normally: the all-in-one machine is powered through a DCDC and a KEY ON pin, then normal values are written into software by using an upper computer, and then contact current limiting is clicked; in the second mode, the battery cannot be powered due to a fault, and the DCDC cannot be started: the BMS is activated by using an external power supply through a CHG-A+ of a normal charging port and a BMS power supply negative interface, the BMS internal parameters are set by using a method of writing false values, then normal charging is carried out, until the battery is charged to a higher voltage value, and then the battery is restored to a normal value. The application has the following advantages: the problem that a vehicle cannot run due to a battery fault can be quickly solved; double setting is adopted, so that the error-proof property of setting is increased; and after the current limiting is removed, the application safety is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of lithium batteries, and particularly relates to a novel over-discharge compensation method and a conventional test method. BACKGROUND

[0002] Due to the fact that the voltage platform of lithium iron phosphate is flat in the middle, and steep at the end of charging and discharging, the SOC in the middle stage is relatively inaccurate if the voltage corresponding method is used, and therefore, the time integration method is used. However, the SOC deviation is large if the end calibration is used in the long-time slow charging state, and especially in winter, due to the inaccuracy of the calculation method, the battery cell is often discharged to a very low voltage, even to an extreme situation, but the SOC is still displayed as high, such as 30 or 40, or some serious faults are difficult to recover, at this time, the car cannot move due to the battery and is stopped on the road without management, causing the car to be stranded. The present application provides a temporary recovery method for the above-mentioned problems, which ensures the temporary recovery of the battery in such a fault, and the method can also be used for testing the battery software. SUMMARY

[0003] In the over-discharge compensation of lithium batteries, due to the inaccuracy of the SOC algorithm and other reasons, especially in low temperature conditions, the SOC is often high, such as 30 or 40, but the single cell has reached a low voltage, such as 2.5V or below, some even reach an extreme situation of 1.8V or below, and some have overcurrent faults in high or low temperature conditions. The present application adopts the following method to recover such faults.

[0004] A novel battery over-discharge compensation method, the method comprising two compensation modes:

[0005] Mode A: fault occurs, but can normally power on;

[0006] Mode B: fault occurs and the battery cannot power on, and the DCDC cannot start;

[0007] The mode A comprises the following steps:

[0008] A1: select the DCDC and KEY ON pin to power the all-in-one machine;

[0009] A2: write the numerical value into the labview software;

[0010] A3: after the numerical value recording is completed, the current limiting is removed;

[0011] The mode B comprises the following steps:

[0012] B1: through the CHG-A of the normal charging port and the BMS power supply negative interface, use external power to activate the all-in-one machine BMS;

[0013] B2: set the internal parameters of the all-in-one machine BMS;

[0014] B3: charge until the voltage of the battery reaches the preset value;

[0015] B4: restore the battery to the normal value.

[0016] Optionally, in step A2, the numerical value is written by the host computer.

[0017] Optionally, in step A3, after clicking to release the current limiting, the numerical parameter is set to the all-in-one machine BMS in the PACK through USB-CAN.

[0018] Optionally, in step B2, the parameters are set by using the labview software to write false numerical values.

[0019] Specifically, the over-discharge power compensation test method written by the background program using the labview software is as follows:

[0020] S1: write the total voltage too high, total current too high, temperature too high four levels, temperature too high five levels, single battery voltage too high four levels, and single battery voltage too high five levels into the setting data parameters in the front column;

[0021] S2: click to set the four-level parameters and the five-level parameters, convert the data in the front column into a part of the downlink message, and set each byte of the two frames of messages as 16 hexadecimal shaped data;

[0022] S3: when clicking to release the current limiting, the function in configuration 1 works, so that the secondary development package of peakcan calls the corresponding function library, and the data is downlinked to the BMS, and the data is downlinked to the DATA1.2.3.4 erasable data register, which is used to replace the existing real numerical value, and the data is reported to the host program, and is uploaded to the upper computer interface through peakcan-usb for wiring, and the host program is also accompanied by other instructions, and the program running rhythm is controlled by the time running function when the host program runs, and when the time running function runs to 30 min, a data reset operation is performed, and the above data is reset to the real numerical value.

[0023] Further, when the labview software is written, the downlink data can be decimal data, and an offset needs to be multiplied or added when the data is downlinked, so that the data is converted to hexadecimal.

[0024] Further, when the current limiting time is released, first, a program is set in the PACK integrated machine BMS, and after the program is changed to release the current limiting for 30 minutes, all values are automatically restored to the real values.

[0025] Compared with the prior art, the application has the following advantages: the problem of vehicle unable to run due to battery failure can be quickly solved; the over-discharged battery can be quickly charged, improving the after-sales convenience; the test time is greatly reduced, and the test efficiency is improved; the double setting increases the mistake-proofing of the setting; the application safety is improved by restoring after half an hour of releasing the current limiting. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is the electrical schematic diagram of the application;

[0027] Figure 2 is the host computer interface diagram of the application;

[0028] Figure 3 is the schematic diagram of the connection method of the host computer and the pack of the application;

[0029] Figure 4 is the host computer background running program diagram of the application;

[0030] Figure 5 is the pack running sequence diagram of the application. DETAILED DESCRIPTION

[0031] The novel over-discharged compensation method of the application will be further described below in combination with the drawings:

[0032] For example, Figures 1-3As shown, a new battery over-discharge compensation method includes two compensation modes. The first method is to use DCDC and KEY ON pin to supply power to the all-in-one machine when a more serious fault occurs, but it can still be powered on normally. Then use the dedicated host computer to write normal values into the labview software. If a single cell is actually 2.3V, which is less than the secondary threshold 2.5V, the actual value is displayed in the single cell voltage overvoltage column in the 1.2 level. This method specifically writes normal values in the 4.5 level. Note that 5 is written in the highest single cell, and 4 is written in the lowest single cell. At this time, the written value is an example of 3.3V for the highest and lowest. Click to set 4-level alarm and set 5-level alarm. Then click to release the current limit. Note that when changing to the above setting 4 and alarm and setting 5 level alarm, all other 4 and 5 level faults must be written with normal values, because all values are written at the same time. For example, the total voltage is written with a value of 3.3*N (N refers to the number of battery strings), the total voltage is too low, the SOC is too high, the SOC is too low, the charging current is too high, the temperature is too low, the single cell voltage is too low, the overall voltage is uneven, the single box temperature is uneven, and the overall temperature is uneven. Don't need to open, don't need to open, discharge current is 0, then the value at this time is the actual value; The 4th level in the temperature too high is the lowest temperature written, and the 5th level is the highest temperature written. At this time, the above operation is performed again to make the single cell, temperature, total pressure and current accurate normal values. The setting 4 level fault and setting 5 level fault in the above operation are written into the preparation register of the configurable parameters in the host computer background running program after the values are written. After clicking to release the current limit, the above parameter settings are set to the all-in-one machine BMS in the PACK through the USB-CAN.

[0033] The second method is to use CHG-A+ and BMS power supply negative interface of normal charging port to activate the all-in-one machine BMS with an external power supply when the battery cannot be powered on after a fault occurs, such as a single cell voltage below 1.8V, which makes the DCDC unable to start. Then use the over-discharge compensation test method written by the labview software to set the false value method to the all-in-one machine BMS internal parameter. Then perform normal charging until the voltage of the battery reaches the preset value (the specific preset value is about 3.0V), and then restore the battery to the normal value. It is worth noting that at this time, the setting 4 level alarm and setting 5 level alarm need to be recorded first, and the current limit is released within 10 seconds after plugging in the gun. Otherwise, the software will cause the mainboard to sleep due to too low voltage.

[0034] As Figures 2-5As shown, according to the over-discharge compensation method described above, the new over-discharge compensation test method is as follows: first, write the total voltage too high, total current too high, temperature too high four levels, temperature too high five levels, single cell voltage too high four levels, single cell voltage too high five levels into the corresponding column setting data parameters; then click on the setting four level parameters and setting five level parameters, and convert the data in the previous column into a part of the downlink message, i.e. 0x2F0, 0x2F1, set each byte of the two frames of messages as hexadecimal data, note that because the data that can be downlinked are all decimal data, an offset needs to be multiplied or added when downlinking the data to make the data easy to convert to hexadecimal; then click on the release flow limit, the function in configuration 1 works, so that the secondary development package of peakcan calls the corresponding function library, and the data is downlinked to the all-in-one machine BMS, or the data is downlinked to the DATA1.2.3.4 erasable data register, which is used to replace the existing real values, and the data is reported to the host program and uploaded to the host computer interface through peakcan-usb for wiring. In addition, the host program is also accompanied by other instructions, such as reporting other data and closing the relay, etc. The program running rhythm is controlled by the time running function when the host program runs, and when the time running function runs to 30 min, a data reset operation is performed to reset the above data to real values.

[0035] In addition, the over-discharge compensation test method written by labview software can also be used for simulation test, for example, writing the value as an abnormal value higher or lower than a certain threshold, this kind of fault can still occur, which can greatly reduce the time of simulating real faults, for example, the real value can be written as 2.49V (i.e. less than 2.5V) to simulate the single cell voltage too low fault.

[0036] The temperature can also be simulated in this way, for example, the maximum temperature and the minimum temperature are both 0 degrees, and the heating is turned on during discharging.

[0037] It is worth noting that if the simulation of real value time is too long, many unexpected faults will occur, for example, the real temperature will not be felt after the heating is turned on, so the battery will be heated all the time, and even the temperature will exceed the limit, for example, more than 100 degrees, so the time to release the flow limit needs to be set in the all-in-one machine BMS program in the PACK, i.e. all the values automatically restore to real values after 30 minutes of releasing the flow limit.

[0038] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit the present application; although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions recorded in the above embodiments can be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1.A novel battery over-discharge compensation method, characterized in that, The method includes two compensation modes: Mode A: malfunction occurs, but can be normally powered on; Mode B: malfunction occurs and the battery cannot be powered on, DCDC cannot be started; The mode A includes the following steps: A1: select DCDC and KEY ON pin all-in-one machine for power supply; A2: write the value into the labview software; A3: after the value record is completed, the current limiting is removed; The mode B includes the following steps: B1: use external power supply to activate the all-in-one machine BMS through the CHG-A+ and BMS power supply negative interface of the normal charging port; B2: set the internal parameters of the all-in-one machine BMS; B3: charge until the voltage of the battery reaches the preset value; B4: restore the battery to the normal value; The test method written by labview software includes the following steps: S1: write the total voltage too high, total current too high, temperature too high four levels, temperature too high five levels, single battery voltage too high four levels, single battery voltage too high five levels into the setting data parameters in the front column; S2: click to set four-level parameters and five-level parameters, convert the data in the front column into a part of the downlink message, and set each byte of the two frames of messages to 16 hexadecimal shaped data; S3: click to remove the current limiting, the function in the configuration works, the secondary development package of peakcan calls the corresponding function library, the data is downlinked to the BMS, the data is downlinked to the DATA1.2.3.4 erasable data register, which is used to replace the existing real value, and the data is reported to the host computer interface through peakcan-usb for display, the host program also has other instructions, the program running rhythm is controlled by the time running function when the host program runs, and the data is reset to the real value when the time running function runs to 30 min; When writing the labview software, the data that can be downlinked is decimal data, and the offset needs to be multiplied or added when downlinking the data to convert the data to hexadecimal; when removing the current limiting time, first set the program in the PACK all-in-one machine BMS, and change the program to automatically restore all values to real values after 30 minutes of current limiting removal. 2.The novel battery over-discharge compensation method of claim 1, characterized in that, In step A2, the value is written by the host computer. 3.The novel battery over-discharge compensation method of claim 1, characterized in that, In step A3, after clicking to remove the current limiting, the value parameter is set to the all-in-one machine BMS in the PACK through USB-CAN. 4.The novel battery over-discharge compensation method of claim 1, characterized in that, In step B2, the parameters are set by using the labview software to write false value method.

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