SOC correction method and device for commercial electric vehicle, storage medium and vehicle
By configuring a standstill time threshold and judging the charge and discharge state in a commercial electric vehicle, the SOC is dynamically corrected, and the problem of large SOC calculation error and low OCV correction probability in the prior art are solved, thereby improving the accuracy of SOC.
Patent Information
- Application Number
- CN202411653894.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-19
- Publication Date
- 2025-02-14
AI Technical Summary
In the prior art, when calculating SOC by the A-time integral algorithm, the cumulative error is large; when calculating SOC by the OCV correction algorithm, the standstill time of commercial electric vehicles is shorter, and the probability of triggering OCV correction is low.
Provide a SOC correction method for commercial electric vehicles. By obtaining vehicle condition information, the SOC is corrected if the SOC is reached; if the SOC is not reached; if the SOC is determined whether the vehicle is in a charging or discharge state, according to The relationship between single voltage and correction voltage dynamically corrects SOC.
The accuracy of SOC is improved, and the trigger probability of OCV correction is increased by shortening the standstill time threshold, thereby avoiding the problem of excessive SOC accumulation error.
Smart Images
Figure CN119428343A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of electric vehicles, and in particular to a SOC correction method, device, storage medium and vehicle for a commercial electric vehicle. Background Art
[0002] As one of the core components of electric vehicles, the Battery Management System (BMS) has always been the focus of electric vehicle research and development. The State of Charge (SOC) is the most critical parameter of BMS. During the operation of the vehicle, the lithium battery undergoes complex chemical reactions, and SOC and other related parameters cannot be directly obtained. They can only be indirectly estimated through the BMS to collect battery voltage and temperature through estimation algorithms. The current mainstream calculation methods are the ampere-hour integration algorithm and the open circuit voltage (OCV) correction algorithm.
[0003] The ampere-hour integration algorithm obtains the SOC by integrating the product of current and time and dividing it by the battery capacity. However, when there is a sampling error in the current, the error of the calculated SOC will continue to accumulate, eventually causing the system error to become larger and larger. The OCV correction algorithm collects the battery voltage when the battery is at rest for a long time without current, and the OCV of the battery can be obtained. Because the OCV of the battery after resting corresponds to the SOC of the battery, the SOC of the battery can be calculated through the corresponding relationship between OCV and SOC. However, the dynamic voltage of the battery after charging and discharging is quite different from the OCV at the static voltage. If you want to obtain the accurate OCV, you must let the battery rest until the voltage is stable, which generally takes 1 to 4 hours. However, commercial electric vehicles are relatively rare in the condition of being at rest for a long time, resulting in a low probability of triggering OCV correction. Summary of the invention
[0004] The present application provides a method, device, storage medium and vehicle for correcting the SOC of a commercial electric vehicle, which is used to solve the problem that when calculating the SOC by the ampere-hour integration algorithm, the accumulated error is large; when calculating the SOC by the OCV correction algorithm, the commercial electric vehicle has a short static time and the probability of triggering the OCV correction algorithm is low. The technical solution is as follows:
[0005] According to a first aspect of the present application, a method for correcting the SOC of a commercial electric vehicle is provided, the method comprising:
[0006] Acquire vehicle condition information of the commercial electric vehicle, and configure a static time threshold according to the vehicle condition information, wherein the static time threshold is less than a default static time;
[0007] After the commercial electric vehicle is powered off and powered on again, obtaining a current rest time of a battery in the commercial electric vehicle;
[0008] If the current rest time reaches the rest time threshold, correcting the SOC;
[0009] If the current rest time does not reach the rest time threshold, determining whether the commercial electric vehicle is in a charging state or a discharging state;
[0010] If the commercial electric vehicle is in a charging state or a discharging state, the cell voltage of the battery when working under predetermined conditions and the correction voltage of a preset SOC correction point are obtained, and the SOC is corrected according to the relationship between the cell voltage and the correction voltage.
[0011] In a possible implementation, configuring the static time threshold according to the vehicle condition information includes:
[0012] If the vehicle condition information is the charge and discharge rate of the battery before it is stationary, detecting whether the charge and discharge rate is continuously within a range for a period of time;
[0013] If the charge / discharge rate is continuously within an interval for a period of time, then searching for a rest time threshold value corresponding to the interval, wherein the value of the interval is positively correlated with the value of the rest time threshold value;
[0014] Configure the idle time threshold.
[0015] In a possible implementation, configuring the static time threshold according to the vehicle condition information includes:
[0016] If the vehicle condition information includes the current battery cycle number and the battery cycle number at the last correction, detecting whether the difference between the current cycle number and the battery cycle number at the last correction is greater than a number threshold;
[0017] If the difference is greater than the number threshold, the static time threshold is configured.
[0018] In a possible implementation, the correcting the SOC includes:
[0019] Correct the current SOC according to the predetermined strategy;
[0020] Obtaining the SOC correction point before correction and the SOC correction point after correction;
[0021] If the difference between the corrected SOC correction point and the pre-corrected SOC correction point is greater than a first threshold, a weighted sum of the pre-corrected SOC correction point and the corrected SOC correction point is calculated, and the corrected SOC correction point is corrected to the weighted sum;
[0022] If the difference between the corrected SOC correction point and the pre-corrected SOC correction point is less than or equal to a first threshold, the corrected SOC correction point is maintained unchanged.
[0023] In a possible implementation, if the commercial electric vehicle is in a discharging state,
[0024] The obtaining of the cell voltage of the battery when it is working under predetermined conditions and the correction voltage of the preset SOC correction point includes: obtaining the lowest cell voltage when the battery is working continuously for a predetermined time at a state lower than the target discharge current, and obtaining a first correction voltage of the first SOC correction point and a second correction voltage of the second SOC correction point;
[0025] The correcting the SOC according to the relationship between the single cell voltage and the correction voltage includes: if the lowest single cell voltage is less than or equal to the first correction voltage, and the lowest single cell voltage is greater than or equal to the second correction voltage, then correcting the current SOC to the first SOC correction point; if the lowest single cell voltage is less than or equal to the second correction voltage, and the current SOC is greater than or equal to the second SOC correction point, then correcting the current SOC to the second SOC correction point.
[0026] In a possible implementation, if the commercial electric vehicle is in a charging state,
[0027] The obtaining of the single cell voltage when the battery is working under predetermined conditions and the correction voltage at a preset SOC correction point includes: obtaining the highest single cell voltage when the battery is working continuously for a predetermined time at a state lower than the target charging current, and obtaining a third correction voltage at a third SOC correction point and a fourth correction voltage at a fourth SOC correction point;
[0028] The SOC is corrected according to the relationship between the single cell voltage and the correction voltage, including: if the highest single cell voltage is less than or equal to the third correction voltage, and the highest single cell voltage is greater than or equal to the fourth correction voltage, then the current SOC is corrected to the fourth SOC correction point; if the highest single cell voltage is greater than or equal to the third correction voltage, then the current SOC is corrected to the third SOC correction point.
[0029] In a possible implementation, the method further includes:
[0030] If the battery continues to operate for a predetermined time at a state where the discharge current is lower than the target discharge current and the lowest cell voltage is lower than a preset termination voltage, the SOC is corrected to a full discharge correction point;
[0031] If the highest single cell voltage of the battery reaches the full-charge voltage corresponding to the current temperature and the charging current drops to the minimum charging allowable current, the SOC is corrected to the full-charge correction point.
[0032] According to a second aspect of the present application, a SOC correction device for a commercial electric vehicle is provided, the device comprising:
[0033] A configuration module, used to obtain vehicle condition information of the commercial electric vehicle, and configure a static time threshold according to the vehicle condition information, wherein the static time threshold is less than a default static time;
[0034] An acquisition module, used for acquiring a current rest time of a battery in the commercial electric vehicle after the commercial electric vehicle is powered off and powered on again;
[0035] A first correction module, configured to correct the SOC if the current rest time reaches the rest time threshold;
[0036] a charge and discharge judgment module, configured to judge whether the commercial electric vehicle is in a charging state or a discharging state if the current resting time does not reach the resting time threshold;
[0037] The second correction module is used to obtain the single cell voltage and the correction voltage of the preset SOC correction point when the commercial electric vehicle is in a charging state or a discharging state, and correct the SOC according to the relationship between the single cell voltage and the correction voltage when the battery is working under predetermined conditions.
[0038] According to a third aspect of the present application, a computer-readable storage medium is provided, wherein at least one instruction is stored in the storage medium, and the at least one instruction is loaded and executed by a processor to implement the SOC correction method for a commercial electric vehicle as described above.
[0039] According to a fourth aspect of the present application, a commercial electric vehicle is provided, and the commercial electric vehicle includes the SOC correction device of the commercial electric vehicle described above.
[0040] The beneficial effects of the technical solution provided by this application include at least:
[0041] Since commercial electric vehicles rarely remain stationary for long periods of time, we can shorten the stationary time threshold based on the vehicle condition information of commercial electric vehicles, thereby increasing the triggering probability of OCV correction, and correcting SOC by correcting OCV, thereby improving the accuracy of SOC.
[0042] When a commercial electric vehicle is in a charging or discharging state, the single cell voltage of the battery when working under predetermined conditions and the correction voltage of the preset SOC correction point can be obtained. The SOC can be dynamically corrected based on the relationship between the single cell voltage and the correction voltage, thereby avoiding the problem of too large cumulative error of the SOC when the commercial electric vehicle is not stationary for a long time, thereby improving the accuracy of the SOC. BRIEF DESCRIPTION OF THE DRAWINGS
[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.
[0044] Figure 1 is a flow chart of a SOC correction method for a commercial electric vehicle provided by an embodiment of the present application;
[0045] Figure 2 is a flow chart of a SOC correction method for a commercial electric vehicle provided by an embodiment of the present application;
[0046] Figure 3 is a schematic diagram of performing SOC correction according to the rest time provided by an embodiment of the present application;
[0047] Figure 4 is a schematic diagram of performing SOC correction according to the charge and discharge state provided by an embodiment of the present application;
[0048] Figure 5 It is a structural block diagram of a SOC correction device for a commercial electric vehicle provided by an embodiment of the present application. DETAILED DESCRIPTION
[0049] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the implementation methods of the present application will be further described in detail below in conjunction with the accompanying drawings.
[0050] There are many kinds of batteries in commercial electric vehicles, and different batteries have different characteristics, resulting in different correction ranges of SOC for different batteries. Taking the battery as a lithium iron phosphate battery, due to the inherent characteristics of lithium iron phosphate, the SOC is in a plateau period of 15% to 95%. At this stage, the open circuit voltage of the lithium iron phosphate battery changes relatively little, and the sensitivity to SOC is low. Therefore, in this embodiment, the correction range of SOC is 0 to 15% and 95% to 100%. That is, when the SOC range is 0 to 15% and 95% to 100%, the following SOC correction method is executed to correct the SOC.
[0051] like Figure 1As shown, it shows a method flow chart of a SOC correction method for a commercial electric vehicle provided by an embodiment of the present application, and the SOC correction method for a commercial electric vehicle can be applied to a commercial electric vehicle. The SOC correction method for a commercial electric vehicle may include:
[0052] Step 101, obtaining vehicle condition information of a commercial electric vehicle, configuring a static time threshold according to the vehicle condition information, and the static time threshold is less than a default static time.
[0053] Since commercial electric vehicles rarely sit still for a long time, if the default rest time (usually 4 hours) is used to trigger the OCV correction, the probability of triggering the OCV correction will be low, which will cause the cumulative error of SOC to become larger and larger, and ultimately reduce the accuracy of SOC. To solve this problem, we can obtain the vehicle condition information of commercial electric vehicles and determine whether to reduce the rest time for triggering the OCV correction based on the vehicle condition information.
[0054] The vehicle condition information may be information reflecting the intensity of the battery operation. For example, when the intensity of the battery operation is determined to be light according to the vehicle condition information, the rest time may be shortened; when the intensity of the battery operation is determined to be heavy according to the vehicle condition information, the rest time may not be shortened. Alternatively, the vehicle condition information may be information reflecting the number of cycles of the battery operation. For example, when the number of cycles of the battery operation is determined to be large according to the vehicle condition information, the rest time may be shortened; when the number of cycles of the battery operation is determined to be small according to the vehicle condition information, the rest time may not be shortened. Of course, the vehicle condition information may also be other information, which is not limited in this embodiment.
[0055] If it is determined that the idle time needs to be shortened, a idle time threshold may be configured, which is smaller than the default idle time. For example, the idle time threshold may be configured to 3 hours, 2 hours, 1 hour, etc. The specific value is not limited in this embodiment.
[0056] Step 102 , after the commercial electric vehicle is powered off and powered on again, the current rest time of the battery in the commercial electric vehicle is obtained.
[0057] The current rest time is the time during which a commercial electric vehicle is powered off and powered on again.
[0058] Step 103: If the current rest time reaches the rest time threshold, the SOC is corrected.
[0059] The commercial electric vehicle can compare the current rest time with the rest time threshold. If the current rest time is greater than or equal to the rest time threshold, it is determined that the current rest time reaches the rest time threshold, triggering SOC correction. The specific correction method is not limited in this embodiment; if the current rest time is less than the rest time threshold, it is determined that the current rest time does not reach the rest time threshold, and step 104 is executed.
[0060] Step 104 : If the current rest time does not reach the rest time threshold, it is determined whether the commercial electric vehicle is in a charging state or a discharging state.
[0061] After being powered on again, commercial electric vehicles may be in a charging state or a discharging state, and SOC correction needs to be performed according to different states.
[0062] Step 105 , if the commercial electric vehicle is in a charging state or a discharging state, the cell voltage of the battery when working under a predetermined condition and the correction voltage of a preset SOC correction point are obtained, and the SOC is corrected according to the relationship between the cell voltage and the correction voltage.
[0063] Specifically, an SOC correction point can be set during the non-plateau period of the battery. When working at a low rate, the current single cell voltage is compared with the correction voltage corresponding to the SOC correction point to determine whether to correct the current SOC. By adding a dynamic correction strategy, the correction probability is increased.
[0064] To summarize, the SOC correction method for a commercial electric vehicle provided in the embodiment of the present application is relatively rare in the operating conditions where commercial electric vehicles are stationary for a long time. Therefore, we can shorten the stationary time threshold according to the vehicle condition information of the commercial electric vehicle, thereby increasing the triggering probability of OCV correction, and correcting the SOC by correcting the OCV, thereby improving the accuracy of the SOC.
[0065] When a commercial electric vehicle is in a charging or discharging state, the single cell voltage of the battery when working under predetermined conditions and the correction voltage of the preset SOC correction point can be obtained. The SOC can be dynamically corrected based on the relationship between the single cell voltage and the correction voltage, thereby avoiding the problem of too large cumulative error of the SOC when the commercial electric vehicle is not stationary for a long time, thereby improving the accuracy of the SOC.
[0066] like Figure 2 As shown, it shows a flow chart of a SOC correction method for a commercial electric vehicle provided by an embodiment of the present application, and the SOC correction method for a commercial electric vehicle can be applied to a commercial electric vehicle. The SOC correction method for a commercial electric vehicle may include:
[0067] Step 201, obtaining vehicle condition information of a commercial electric vehicle, configuring a static time threshold according to the vehicle condition information, and the static time threshold is less than a default static time.
[0068] The vehicle condition information may be information reflecting the intensity of the battery operation. For example, when the intensity of the battery operation is determined to be light according to the vehicle condition information, the rest time may be shortened; when the intensity of the battery operation is determined to be heavy according to the vehicle condition information, the rest time may not be shortened. Alternatively, the vehicle condition information may be information reflecting the number of cycles of the battery operation. For example, when the number of cycles of the battery operation is determined to be large according to the vehicle condition information, the rest time may be shortened; when the number of cycles of the battery operation is determined to be small according to the vehicle condition information, the rest time may not be shortened. Of course, the vehicle condition information may also be other information, which is not limited in this embodiment.
[0069] In this embodiment, the charge and discharge rate of the battery before it is at rest can be used to indicate the intensity of the battery's operation. Then, configuring the rest time threshold according to the vehicle condition information may include: if the vehicle condition information is the charge and discharge rate of the battery before it is at rest, detecting whether the charge and discharge rate is continuously in an interval for a period of time; if the charge and discharge rate is continuously in an interval for a period of time, searching for the rest time threshold corresponding to the interval, wherein the numerical value of the interval is positively correlated with the value of the rest time threshold; configuring the rest time threshold. The relationship between the numerical value of the interval and the rest time threshold can be calculated according to a formula, or configured according to an empirical value, which is not limited in this embodiment.
[0070] Specifically, multiple charge and discharge rate intervals can be pre-set, and each interval corresponds to a rest time threshold. For example, one interval is less than (0, 1 / 3C), and its corresponding rest time threshold is 1 hour; another interval is (1 / 3C, 1 / 2C), and its corresponding rest time threshold is 2 hours. The value of the time period can be set according to demand, for example, set to more than 30 minutes.
[0071] Assuming that the charge and discharge rate of the battery before standing still is less than 0.5C and greater than 1 / 3C and is maintained for more than 30 minutes, the standing time threshold is set to 2 hours; assuming that the charge and discharge rate of the battery before standing still is less than 1 / 3C and is maintained for more than 30 minutes, the standing time threshold is set to 1 hour.
[0072] In this embodiment, the difference between the current cycle number and the battery cycle number at the last correction can be used to represent the number of cycles of the battery operation. Then, configuring the standstill time threshold according to the vehicle condition information may include: if the vehicle condition information includes the current battery cycle number and the battery cycle number at the last correction, detecting whether the difference between the current cycle number and the battery cycle number at the last correction is greater than the number threshold; if the difference is greater than the number threshold, configuring the standstill time threshold.
[0073] Specifically, a number threshold can be set in advance, and the current cycle number N and the battery cycle number Nc for each OCV correction are recorded; the difference between the current cycle number N and the battery cycle number Nc for OCV correction is calculated; the difference N-Nc is compared with the number threshold No; if N-Nc>No, it is considered that OCV correction has not been performed for a long time. In order to prevent the SOC cumulative error from being too large, it is necessary to shorten the OCV correction rest period to perform a round of rapid OCV correction; if N-Nc<No, there is no need to perform a round of rapid OCV correction.
[0074] Step 202 , after the commercial electric vehicle is powered off and powered on again, the current rest time of the battery in the commercial electric vehicle is obtained.
[0075] The current rest time is the time during which a commercial electric vehicle is powered off and powered on again.
[0076] Step 203: If the current rest time reaches the rest time threshold, the SOC is corrected.
[0077] The commercial electric vehicle can compare the current rest time with the rest time threshold. If the current rest time is greater than or equal to the rest time threshold, it is determined that the current rest time reaches the rest time threshold, triggering SOC correction. The specific correction method is not limited in this embodiment; if the current rest time is less than the rest time threshold, it is determined that the current rest time does not reach the rest time threshold, and step 204 is executed.
[0078] In order to prevent miscorrection, the current SOC can be corrected according to a predetermined strategy; the SOC correction point before correction and the SOC correction point after correction are obtained; if the difference between the SOC correction point after correction and the SOC correction point before correction is greater than the first threshold, the weighted sum of the SOC correction point before correction and the SOC correction point after correction is calculated, and the SOC correction point after correction is corrected to the weighted sum; if the difference between the SOC correction point after correction and the SOC correction point before correction is less than or equal to the first threshold, the SOC correction point after correction is kept unchanged. Among them, the weights of the SOC correction point before correction and the SOC correction point after correction, and the first threshold can be set according to needs, and are not limited in this embodiment.
[0079] In one example, assuming that the first threshold is 10%, the weight of the SOC correction point before correction is 0.7, and the weight of the SOC correction point after correction is 0.3, then when the difference between the corrected SOC and the SOC before correction is greater than 10%, SOC = SOC before correction × 0.7 + SOC after correction × 0.3; when the difference between the corrected SOC and the SOC before correction is ≤ 10%, SOC = SOC after correction.
[0080] Step 204: If the current rest time does not reach the rest time threshold, it is determined whether the commercial electric vehicle is in a charging state or a discharging state.
[0081] After being powered on again, commercial electric vehicles may be in a charging state or a discharging state, and SOC correction needs to be performed according to different states. Specifically, the SOC correction point can be set during the non-plateau period of the battery. When working at a low rate, the current single cell voltage is compared with the correction voltage corresponding to the SOC correction point to determine whether to correct the current SOC. By adding a dynamic correction strategy, the correction probability is increased.
[0082] When the commercial electric vehicle is in a discharging state, steps 205-206 are executed to dynamically correct the SOC; when the commercial electric vehicle is in a charging state, steps 207-208 are executed to dynamically correct the SOC.
[0083] Step 205 , if the commercial electric vehicle is in a discharging state, obtain the lowest cell voltage when the battery continuously operates at a state lower than the target discharge current for a predetermined time, and obtain a first correction voltage at a first SOC correction point and a second correction voltage at a second SOC correction point.
[0084] When a commercial electric vehicle is in a discharging state, a dynamic correction is performed within the range of 0 to 15%. Specifically, a first SOC correction point and a second SOC correction point can be set within the range of 0 to 15%, and the values of the two SOC correction points can be set according to demand. Then, the lowest cell voltage when the battery operates at a discharge current lower than the target discharge current (such as 0.5C) for a predetermined time (such as 30s) is obtained through experiments at two correction points in different temperature ranges, and the maximum lowest cell voltage value is obtained after a large number of experiments. For the sake of distinction, in this embodiment, the lowest cell voltage value of the first SOC correction point is referred to as the first correction voltage, and the lowest cell voltage value of the second SOC correction point is referred to as the second correction voltage.
[0085] Step 206, if the lowest cell voltage is less than or equal to the first correction voltage, and the lowest cell voltage is greater than or equal to the second correction voltage, the current SOC is corrected to the first SOC correction point; if the lowest cell voltage is less than or equal to the second correction voltage, and the current SOC is greater than or equal to the second SOC correction point, the current SOC is corrected to the second SOC correction point.
[0086] Assuming the first SOC correction point is 8% and the second SOC correction point is 13%, then:
[0087] (1) 13% correction point voltage ≥ minimum cell voltage ≥ 8% correction point voltage, correct the SOC to 13%;
[0088] (2) The lowest cell voltage is ≤8% correction point voltage, and the current SOC is greater than 8%, and the SOC is corrected to 8%.
[0089] In order to prevent erroneous correction, each time a dynamic correction is performed, if the difference between the SOC after correction and the SOC before correction is greater than 10%, a maximum correction of 10% is made.
[0090] In order to avoid frequent corrections, a certain period of time must pass after each dynamic correction before the next dynamic correction can be triggered.
[0091] If the battery continues to work for a predetermined time at a state lower than the target discharge current and the lowest cell voltage is lower than the preset termination voltage, the SOC is corrected to the full discharge correction point. Considering that the discharge capacity of the battery at different temperatures is different, its preset discharge termination voltage is also different, so it is necessary to find the experimental data according to the current temperature to obtain the current preset termination voltage. If the discharge current is less than 0.5C and the lowest cell voltage is lower than the preset termination voltage for 3 seconds, the SOC is corrected to 0. This step is called full discharge correction.
[0092] Step 207 , if the commercial electric vehicle is in a charging state, obtain the highest cell voltage when the battery continuously operates at a state lower than the target charging current for a predetermined time, and obtain a third corrected voltage at a third SOC correction point and a fourth corrected voltage at a fourth SOC correction point.
[0093] When commercial electric vehicles are in a charging state, in order to prevent commercial electric vehicles from being undercharged for a long time, dynamic correction is performed within the range of 95% to 100%. Specifically, the third SOC correction point and the fourth SOC correction point can be set within the range of 95% to 100%, and the values of these two SOC correction points can be set according to demand. Then, the highest single cell voltage when the battery works at a lower than target charging current (such as 0.2C) for a predetermined time (such as 5s) when the SOC is at two correction points in different temperature ranges is obtained through experiments, and the highest single cell voltage value is obtained after a large number of experiments. For the sake of distinction, in this embodiment, the lowest single cell voltage value of the third SOC correction point is referred to as the third correction voltage, and the lowest single cell voltage value of the fourth SOC correction point is referred to as the fourth correction voltage.
[0094] Step 208, if the highest cell voltage is less than or equal to the third correction voltage and the highest cell voltage is greater than or equal to the fourth correction voltage, the current SOC is corrected to the fourth SOC correction point; if the highest cell voltage is greater than or equal to the third correction voltage, the current SOC is corrected to the third SOC correction point.
[0095] Assuming that the third SOC correction point is 99% and the fourth SOC correction point is 97%, then:
[0096] (1) 99% correction point voltage ≥ maximum cell voltage ≥ 97% correction point voltage, correct the SOC to 97%.
[0097] (2) The highest cell voltage is ≥ 99% of the correction point voltage, and the SOC is corrected to 99%.
[0098] In order to prevent erroneous correction, each time a dynamic correction is performed, if the difference between the SOC after correction and the SOC before correction is greater than 10%, a maximum correction of 10% is made.
[0099] In order to avoid frequent corrections, a certain period of time must pass after each dynamic correction before the next dynamic correction can be triggered.
[0100] If the highest cell voltage of the battery reaches the full-charge voltage corresponding to the current temperature, and the charging current drops to the minimum allowed charging current, the SOC is corrected to the full-charge correction point. Among them, when the battery is charged to a specific condition (the highest cell voltage reaches the full-charge voltage at the current temperature, and the charging current drops to the minimum allowed charging current), the battery is considered to be fully charged. At this time, the battery's SOC is corrected to 100%. This step is called full-charge correction.
[0101] To summarize, the SOC correction method for a commercial electric vehicle provided in the embodiment of the present application is relatively rare in the operating conditions where commercial electric vehicles are stationary for a long time. Therefore, we can shorten the stationary time threshold according to the vehicle condition information of the commercial electric vehicle, thereby increasing the triggering probability of OCV correction, and correcting the SOC by correcting the OCV, thereby improving the accuracy of the SOC.
[0102] When a commercial electric vehicle is in a charging or discharging state, the single cell voltage of the battery when working under predetermined conditions and the correction voltage of the preset SOC correction point can be obtained. The SOC can be dynamically corrected based on the relationship between the single cell voltage and the correction voltage, thereby avoiding the problem of too large cumulative error of the SOC when the commercial electric vehicle is not stationary for a long time, thereby improving the accuracy of the SOC.
[0103] like Figure 3 As shown, the following describes the determination process of whether to perform OCV correction based on the vehicle stationary time.
[0104] (1) Obtain the vehicle idle time after the commercial electric vehicle is powered off and then powered on again;
[0105] (2) determining whether the vehicle's stationary time is greater than a default stationary time H1; if the vehicle's stationary time is greater than the default stationary time H1, triggering OCV correction; if the vehicle's stationary time is less than the default stationary time H1, executing step (3);
[0106] (3) When the charge / discharge rate of the battery before standing still is less than 0.5C and is maintained for more than 30 minutes, determine whether the vehicle standing still time is greater than its corresponding standing time threshold H2. If the vehicle standing still time is greater than the standing still time threshold H2, trigger OCV correction; if the vehicle standing still time is less than the standing still time threshold H2, execute step (4);
[0107] (4) When the charge / discharge rate of the battery before standing still is less than 1 / 3C and is maintained for more than 30 minutes, determine whether the vehicle standing still time is greater than its corresponding standing time threshold H3. If the vehicle standing still time is greater than the standing still time threshold H3, trigger OCV correction; if the vehicle standing still time is less than the standing still time threshold H3, execute step (5);
[0108] (5) When the difference between the current cycle number and the battery cycle number at the last correction is greater than the number threshold, determine whether the vehicle's static time is greater than its corresponding static time threshold H4. If the vehicle's static time is greater than the static time threshold H4, OCV correction is triggered; if the vehicle's static time is less than the static time threshold H4, OCV correction is not triggered.
[0109] like Figure 4 As shown, the following describes the judgment process of whether to perform OCV correction according to the charge and discharge state.
[0110] (1) If based on Figure 3 The process shown determines that the OCV correction condition is not met, and then determines whether the commercial electric vehicle is in a charging state;
[0111] (2) If the commercial electric vehicle is in a charging state, determine whether the full charge correction condition is met. If the full charge correction condition is met, trigger the full charge correction; if the full charge correction condition is not met, execute step (3);
[0112] (3) determining whether the charging dynamic correction condition is met, and if so, triggering the charging dynamic correction strategy (i.e., executing steps 207-208); if not, not correcting the SOC;
[0113] (4) If the commercial electric vehicle is in a discharging state, determine whether the full discharge correction condition is met. If the full discharge correction condition is met, trigger the full discharge correction; if the full discharge correction condition is not met, execute step (5);
[0114] (5) Determine whether the discharge dynamic correction condition is met. If the discharge dynamic correction condition is met, trigger the discharge dynamic correction strategy (i.e., execute steps 205-206); if the discharge dynamic correction condition is not met, do not correct the SOC.
[0115] like Figure 5As shown, it shows a structural block diagram of a SOC correction device for a commercial electric vehicle provided by an embodiment of the present application, and the SOC correction device for a commercial electric vehicle can be applied to a commercial electric vehicle. The SOC correction device for a commercial electric vehicle may include:
[0116] A configuration module 510 is used to obtain vehicle condition information of the commercial electric vehicle, and configure a static time threshold according to the vehicle condition information, wherein the static time threshold is less than a default static time;
[0117] An acquisition module 520, for acquiring a current rest time of a battery in the commercial electric vehicle after the commercial electric vehicle is powered off and powered on again;
[0118] A first correction module 530, configured to correct the SOC if the current rest time reaches a rest time threshold;
[0119] The charging and discharging judgment module 540 is used to judge whether the commercial electric vehicle is in a charging state or a discharging state if the current resting time does not reach the resting time threshold;
[0120] The second correction module 550 is used to obtain the cell voltage and the correction voltage of the preset SOC correction point when the commercial electric vehicle is in a charging state or a discharging state, and correct the SOC according to the relationship between the cell voltage and the correction voltage when the battery is working under predetermined conditions.
[0121] In an optional embodiment, the configuration module 510 is further configured to:
[0122] If the vehicle condition information is the charge and discharge rate of the battery before it is stationary, then check whether the charge and discharge rate is continuously within a certain range for a period of time;
[0123] If the charge / discharge rate is continuously within a certain interval for a period of time, the corresponding rest time threshold of the interval is searched, wherein the value of the interval is positively correlated with the value of the rest time threshold;
[0124] Configure the idle time threshold.
[0125] In an optional embodiment, the configuration module 510 is further configured to:
[0126] If the vehicle condition information includes the current battery cycle number and the battery cycle number at the last correction, then detecting whether the difference between the current cycle number and the battery cycle number at the last correction is greater than a number threshold;
[0127] If the difference is greater than the number threshold, configure the idle time threshold.
[0128] In an optional embodiment, the first correction module 530 is further configured to:
[0129] Correct the current SOC according to the predetermined strategy;
[0130] Obtaining the SOC correction point before correction and the SOC correction point after correction;
[0131] If the difference between the corrected SOC correction point and the SOC correction point before correction is greater than a first threshold, a weighted sum of the SOC correction point before correction and the SOC correction point after correction is calculated, and the corrected SOC correction point is corrected to the weighted sum;
[0132] If the difference between the corrected SOC correction point and the SOC correction point before correction is less than or equal to the first threshold, the corrected SOC correction point is kept unchanged.
[0133] In an optional embodiment, if the commercial electric vehicle is in a discharging state,
[0134] The second correction module 550 is further used to: obtain the lowest cell voltage when the battery continuously operates at a state lower than the target discharge current for a predetermined time, and obtain the first correction voltage at the first SOC correction point and the second correction voltage at the second SOC correction point;
[0135] The second correction module 550 is further used to: if the lowest cell voltage is less than or equal to the first correction voltage, and the lowest cell voltage is greater than or equal to the second correction voltage, then correct the current SOC to the first SOC correction point; if the lowest cell voltage is less than or equal to the second correction voltage, and the current SOC is greater than or equal to the second SOC correction point, then correct the current SOC to the second SOC correction point.
[0136] In an optional embodiment, if the commercial electric vehicle is in a charging state,
[0137] The second correction module 550 is further used to: obtain the highest cell voltage when the battery continuously operates at a state lower than the target charging current for a predetermined time, and obtain a third correction voltage at a third SOC correction point and a fourth correction voltage at a fourth SOC correction point;
[0138] The second correction module 550 is further used to: if the highest cell voltage is less than or equal to the third correction voltage and the highest cell voltage is greater than or equal to the fourth correction voltage, then correct the current SOC to the fourth SOC correction point; if the highest cell voltage is greater than or equal to the third correction voltage, then correct the current SOC to the third SOC correction point.
[0139] In an optional embodiment, the second correction module 550 is further configured to:
[0140] If the battery continues to operate for a predetermined time at a discharge current lower than the target discharge current and the lowest cell voltage is lower than the preset termination voltage, the SOC is corrected to the full discharge correction point;
[0141] If the highest single cell voltage of the battery reaches the full-charge voltage corresponding to the current temperature and the charging current drops to the minimum allowable charging current, the SOC is corrected to the full-charge correction point.
[0142] To summarize, the SOC correction device for a commercial electric vehicle provided in the embodiment of the present application is relatively seldom used in commercial electric vehicles where the vehicle is stationary for a long time. Therefore, we can shorten the stationary time threshold according to the vehicle condition information of the commercial electric vehicle, thereby increasing the triggering probability of the OCV correction, and correcting the SOC by correcting the OCV, thereby improving the accuracy of the SOC.
[0143] When a commercial electric vehicle is in a charging or discharging state, the single cell voltage of the battery when working under predetermined conditions and the correction voltage of the preset SOC correction point can be obtained. The SOC can be dynamically corrected based on the relationship between the single cell voltage and the correction voltage, thereby avoiding the problem of too large cumulative error of the SOC when the commercial electric vehicle is not stationary for a long time, thereby improving the accuracy of the SOC.
[0144] An embodiment of the present application provides a computer-readable storage medium, wherein the storage medium stores at least one instruction, and the at least one instruction is loaded and executed by a processor to implement the SOC correction method for a commercial electric vehicle as described above.
[0145] An embodiment of the present application provides a commercial electric vehicle, which includes the SOC correction device of any of the above commercial electric vehicles.
[0146] It should be noted that: the SOC correction device for commercial electric vehicles provided in the above embodiments only uses the division of the above functional modules as an example to illustrate when performing SOC correction of commercial electric vehicles. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the SOC correction device for commercial electric vehicles is divided into different functional modules to complete all or part of the functions described above. In addition, the SOC correction device for commercial electric vehicles provided in the above embodiments and the SOC correction method embodiment for commercial electric vehicles belong to the same concept, and the specific implementation process is detailed in the method embodiment, which will not be repeated here.
[0147] A person skilled in the art will understand that all or part of the steps to implement the above embodiments may be accomplished by hardware or by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a disk or an optical disk, etc.
[0148] The above description is not intended to limit the embodiments of the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application should be included in the protection scope of the embodiments of the present application.
Claims
1. A method for correcting the SOC of a commercial electric vehicle, characterized in that: The method comprises: Acquire vehicle condition information of the commercial electric vehicle, and configure a static time threshold according to the vehicle condition information, wherein the static time threshold is less than a default static time; After the commercial electric vehicle is powered off and powered on again, obtaining a current rest time of a battery in the commercial electric vehicle; If the current rest time reaches the rest time threshold, correcting the SOC; If the current rest time does not reach the rest time threshold, determining whether the commercial electric vehicle is in a charging state or a discharging state; If the commercial electric vehicle is in a charging state or a discharging state, the cell voltage of the battery when working under predetermined conditions and the correction voltage of a preset SOC correction point are obtained, and the SOC is corrected according to the relationship between the cell voltage and the correction voltage.
2. The SOC correction method for a commercial electric vehicle according to claim 1, characterized in that: The configuring the static time threshold according to the vehicle condition information includes: If the vehicle condition information is the charge and discharge rate of the battery before it is stationary, detecting whether the charge and discharge rate is continuously within a range for a period of time; If the charge / discharge rate is continuously within an interval for a period of time, then searching for a rest time threshold value corresponding to the interval, wherein the value of the interval is positively correlated with the value of the rest time threshold value; Configure the idle time threshold.
3. The SOC correction method for a commercial electric vehicle according to claim 1, characterized in that: The configuring the static time threshold according to the vehicle condition information includes: If the vehicle condition information includes the current battery cycle number and the battery cycle number at the last correction, detecting whether the difference between the current cycle number and the battery cycle number at the last correction is greater than a number threshold; If the difference is greater than the number threshold, the static time threshold is configured.
4. The SOC correction method for a commercial electric vehicle according to claim 3, characterized in that: The modified SOC comprises: Correct the current SOC according to the predetermined strategy; Obtaining the SOC correction point before correction and the SOC correction point after correction; If the difference between the corrected SOC correction point and the pre-corrected SOC correction point is greater than a first threshold, a weighted sum of the pre-corrected SOC correction point and the corrected SOC correction point is calculated, and the corrected SOC correction point is corrected to the weighted sum; If the difference between the corrected SOC correction point and the pre-corrected SOC correction point is less than or equal to a first threshold, the corrected SOC correction point is maintained unchanged.
5. The SOC correction method for a commercial electric vehicle according to claim 1, characterized in that: If the commercial electric vehicle is in a discharging state, The obtaining of the cell voltage of the battery when it is working under predetermined conditions and the correction voltage of the preset SOC correction point includes: obtaining the lowest cell voltage when the battery is working continuously for a predetermined time at a state lower than the target discharge current, and obtaining a first correction voltage of the first SOC correction point and a second correction voltage of the second SOC correction point; The correcting the SOC according to the relationship between the single cell voltage and the correction voltage includes: if the lowest single cell voltage is less than or equal to the first correction voltage, and the lowest single cell voltage is greater than or equal to the second correction voltage, then correcting the current SOC to the first SOC correction point; if the lowest single cell voltage is less than or equal to the second correction voltage, and the current SOC is greater than or equal to the second SOC correction point, then correcting the current SOC to the second SOC correction point.
6. The SOC correction method for a commercial electric vehicle according to claim 1, characterized in that: If the commercial electric vehicle is in a charging state, The obtaining of the single cell voltage when the battery is working under predetermined conditions and the correction voltage at a preset SOC correction point includes: obtaining the highest single cell voltage when the battery is working continuously for a predetermined time at a state lower than the target charging current, and obtaining a third correction voltage at a third SOC correction point and a fourth correction voltage at a fourth SOC correction point; The SOC is corrected according to the relationship between the single cell voltage and the correction voltage, including: if the highest single cell voltage is less than or equal to the third correction voltage, and the highest single cell voltage is greater than or equal to the fourth correction voltage, then the current SOC is corrected to the fourth SOC correction point; if the highest single cell voltage is greater than or equal to the third correction voltage, then the current SOC is corrected to the third SOC correction point.
7. The SOC correction method for a commercial electric vehicle according to claim 5 or 6, characterized in that: The method further comprises: If the battery continues to operate for a predetermined time at a state where the discharge current is lower than the target discharge current and the lowest cell voltage is lower than a preset termination voltage, the SOC is corrected to a full discharge correction point; If the highest single cell voltage of the battery reaches the full-charge voltage corresponding to the current temperature and the charging current drops to the minimum charging allowable current, the SOC is corrected to the full-charge correction point.
8. A SOC correction device for a commercial electric vehicle, characterized in that: The device comprises: A configuration module, used to obtain vehicle condition information of the commercial electric vehicle, and configure a static time threshold according to the vehicle condition information, wherein the static time threshold is less than a default static time; An acquisition module, used for acquiring a current rest time of a battery in the commercial electric vehicle after the commercial electric vehicle is powered off and powered on again; A first correction module, configured to correct the SOC if the current rest time reaches the rest time threshold; a charge and discharge judgment module, configured to judge whether the commercial electric vehicle is in a charging state or a discharging state if the current resting time does not reach the resting time threshold; The second correction module is used to obtain the single cell voltage and the correction voltage of the preset SOC correction point when the commercial electric vehicle is in a charging state or a discharging state, and correct the SOC according to the relationship between the single cell voltage and the correction voltage when the battery is working under predetermined conditions.
9. A computer-readable storage medium, characterized in that: The storage medium stores at least one instruction, and the at least one instruction is loaded and executed by the processor to implement the SOC correction method for a commercial electric vehicle as described in any one of claims 1 to 7.
10. A commercial electric vehicle, characterized in that: The commercial electric vehicle comprises: the SOC correction device for the commercial electric vehicle as claimed in claim 8.