Charging request current testing method for battery management system

Abstract

The invention discloses a charging request current test method for a battery management system, and the method is characterized in that the method comprises the steps: obtaining a maximum value Vcellmax or a real SOC value of a single voltage, a highest cell temperature Tmax, and a lowest cell temperature Tmin sent by the battery management system; on the basis of the Vcellmax or the SOC value, the Tmax and the Tmin, table look-up is carried out in a charging current MAP table of the battery charging characteristics, the maximum temperature current IMAPTmax and the minimum temperature current IMAPTmin are obtained, and the smaller value of the maximum temperature current IMAPTmax and the minimum temperature current IMAPTmin is taken as a target table look-up current IMAP; the method comprises the following steps: acquiring a charging pile limiting current ICharStaLimit and a whole vehicle limiting current IVehileLimit; the current charging request current value CharCurReq is read; comparing the relationship among the IMAP, the ICharStaLimit, the IVehileLimit and the CharCurReq, and sequentially judging whether the current charging request is in the following states: a, limiting the charging pile; b, limiting the whole vehicle; c, requesting according to an MAP table; d, limiting the request according to the proportion; e, an abnormal request; and outputting a group of test judgment signals according to the judgment result, including a request state result value IRsult and a proportion coefficient IRatio, and quickly judging the source and the limit level of the charging request current.

Description

Technical Field

[0001] The present invention relates to the technical field of battery management systems, and particularly to a method for testing the charging request current for a battery management system. Background Art

[0002] In the battery management system (Battery Management System, abbreviated as BMS) of new energy vehicles, the charging current strategy is crucial for battery safety and charging efficiency. In the prior art, the BMS mainly obtains the corresponding charging current value by referring to a two-dimensional MAP table based on the state parameters of the battery, such as the cell voltage, battery temperature, SOC, etc. At the same time, to meet the safety strategies of the vehicle control system and the charging pile, the system also needs to perform multi-level proportional restrictions on the charging request current, such as 20%, 40%, 60%, etc.

[0003] However, during the testing and verification process, since the charging current of the BMS is obtained by looking up a table depending on multi-dimensional state variables, especially in the case of faults or restricted operating conditions, it is necessary to look up the table first and then make a judgment in combination with the ratio. This process is cumbersome, and test engineers need to frequently refer to the original MAP table and manually calculate, resulting in low efficiency and being not conducive to automated testing and rapid analysis. Therefore, there is an urgent need for an optimized test logic to improve the test efficiency and the intuitiveness of result determination. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for testing the charging request current for a battery management system. Through a systematic judgment logic and result signal output, it is no longer necessary to repeatedly refer to the two-dimensional MAP table and manually calculate, greatly improving the test efficiency, and it is especially suitable for automated testing scenarios.

[0005] The technical solution adopted by the present invention to solve the above technical problems is as follows:

[0006] A method for testing the charging request current for a battery management system includes the following steps:

[0007] S1. Obtain the cell parameters sent by the battery management system, including: the maximum cell voltage Vcell_max or the true SOC value, the highest cell temperature Tmax, and the lowest cell temperature Tmin;

[0008] S2. Look up tables in the charging current MAP table of the battery charging characteristics based on Vcell_max or the SOC value and Tmax, Tmin respectively to obtain the maximum temperature current I_MAP_Tmax and the minimum temperature current I_MAP_Tmin, and take the smaller value of the two as the target look-up table current I_MAP;

[0009] S3. Obtain the external system limit parameters, including the charging pile limit current I_CharStaLimit and the vehicle limit current I_VehicleLimit;

[0010] S4. Read the current charging request current value CharCurReq sent by the battery management system;

[0011] S5. Compare the relationships between I_MAP, I_CharStaLimit, I_VehicleLimit and CharCurReq respectively, and sequentially determine whether the current charging request is in:

[0012] a. Charging pile limit;

[0013] b. Vehicle limit;

[0014] c. Request according to the MAP table: I_MAP≈CharCurReq,

[0015] d. Request according to the proportional limit: I_MAP≈CharCurReq×ratio,

[0016] e. Abnormal request;

[0017] S6. Output a set of test judgment signals according to the determination result, including the request status result value I_Result and the ratio coefficient I_Ratio, to quickly judge the source and limit level of the charging request current.

[0018] Preferably, in step S5, when CharCurReq≈I_CharStaLimit (error ±1A) and I_MAP is greater than I_CharStaLimit, it indicates a charging pile limit, and at this time, assign I_Result = 6.

[0019] Preferably, in step S5, when CharCurReq≈I_VehicleLimit (error ±1A) and I_MAP is greater than I_VehicleLimit, it indicates a vehicle limit, and at this time, assign I_Result = 7.

[0020] Preferably, in step S5, after determining the charging pile limit and the vehicle limit, judge according to the MAP table request. When I_MAP and CharCurReq are equal within the error range of ±2A, it is judged as not restricted, and charge according to the MAP. At this time, assign I_Result = 1 and I_Ratio = 1.

[0021] Preferably, according to the MAP table request determination, when I_MAP is equal to CharCurReq × 0.8 within the error range of ±2A, it is determined as level 1 charging limit. At this time, assign I_Result = 1 and I_Ratio = 0.8.

[0022] Preferably, according to the MAP table request determination, when I_MAP is equal to CharCurReq × 0.6 within the error range of ±2A, it is determined as level 2 charging limit. At this time, assign I_Result = 2 and I_Ratio = 0.6.

[0023] Preferably, according to the MAP table request determination, when I_MAP is equal to CharCurReq × 0.3 within the error range of ±2A, it is determined as level 3 charging limit. At this time, assign I_Result = 3 and I_Ratio = 0.3.

[0024] Preferably, when CharCurReq = 0A, it indicates that the charging current limit is 0A. At this time, assign I_Result = 4 and I_Ratio = 0.

[0025] Preferably, it is characterized in that when the proportional relationship between I_MAP and CharCurReq is not satisfied, it indicates an abnormal request. Calculate their ratio and set I_Result = 5, and I_Ratio is the calculated ratio.

[0026] Compared with the prior art, the advantages of the present invention are as follows:

[0027] 1. Through systematic judgment logic and result signal output, there is no need to repeatedly consult the two-dimensional MAP table and manually convert, which greatly improves the test efficiency, especially suitable for automated test scenarios.

[0028] 2. Adopt standardized result signal I_Result and proportional signal I_Ratio. After improvement, by reading the value of the result signal I_Result, it can be clear that the charging request current value sent by the current battery management system is charging according to the MAP, vehicle limit value, charging pile limit value or other restrictions according to the limit level ratio. According to the duty cycle limit, through I_Ratio, it can be known what the ratio is, making the test analysis process clearer and more transparent.

[0029] 3. Considering various actual charging states such as faults, restrictions, and abnormalities, it has strong working condition adaptability and improves the robustness of the method.

[0030] 4. Facilitate integrated development: The logic of this test method is clear and the judgment process is systematic, which is convenient to be integrated into the vehicle diagnostic system or automated test platform to realize online monitoring and real-time analysis. Description of the Drawings

[0031] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0032] Figure 1 It is a flowchart for calculating the requested current in the present invention;

[0033] Figure 2 It is a flowchart for automatically checking the charging current in the present invention. Specific Embodiments

[0034] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the drawings. Obviously, the described embodiments are some embodiments of the present invention, rather than all embodiments.

[0035] Embodiment:

[0036] A method for testing the charging request current of a battery management system, and the test logic is as follows:

[0037] S1. Read the maximum physical value Vcell_max of the single-cell voltage or the physical value of the true SOC sent by the battery management system, the physical value of the maximum cell temperature Tmax, and the physical value of the minimum cell temperature Tmin;

[0038] S2. Import the charging current MAP table of the battery characteristics;

[0039] S3. Respectively use the maximum physical value Vcell_max of the single-cell voltage or the physical value of the true SOC and the maximum cell temperature Tmax and the minimum cell temperature Tmin to look up the discharge power table to calculate the maximum temperature current I_MAP_Tmax and the minimum temperature current I_MAP_Tmin, and finally take the smaller value to obtain the I_MAP look-up current;

[0040] S4. Obtain the I_CharStaLimit charging pile limit current through the maximum and minimum currents of the charging pile; obtain the I_VehicleLimit vehicle limit current through the maximum and minimum currents of the whole vehicle;

[0041] S5. In the charging process, read the physical value of the charging request current CharCurReq sent by the battery management system;

[0042] S6. Compare whether CharCurReq is equal to I_CharStaLimit (with an error of ±1A), and determine that I_MAP is greater than I_CharStaLimit. If both conditions are met, assign I_Result = 6 to indicate charger limit;

[0043] S7. Compare whether CharCurReq is equal to I_VehicleLimit (with an error of ±1A), and determine that I_MAP is greater than I_VehicleLimit. If both conditions are met, assign I_Result = 7 to indicate vehicle limit;

[0044] S8. Compare whether I_MAP is equal to CharCurReq (with an error of ±2A). If they are equal, assign I_Result = 1 to indicate unrestricted charging according to MAP, and the ratio is I_Ratio = 1;

[0045] S9. Compare whether I_MAP is equal to CharCurReq * 0.8 (with an error of ±2A). If they are equal, assign I_Result = 1 to indicate charging restricted by MAP level 1, and the ratio is I_Ratio = 0.8;

[0046] S10. Compare whether I_MAP is equal to CharCurReq * 0.6 (with an error of ±2A). If they are equal, assign I_Result = 2 to indicate charging restricted by MAP level 2, and the ratio is I_Ratio = 0.6;

[0047] S11. Compare whether I_MAP is equal to CharCurReq * 0.6 (with an error of ±2A). If they are equal, assign I_Result = 3 to indicate charging restricted by MAP level 3, and the ratio is I_Ratio = 0.3;

[0048] S12. If CharCurReq is equal to 0A, assign I_Result = 4 to indicate that the charging current limit is 0A, and the ratio is I_Ratio = 0;

[0049] S13. Calculate the ratio of CharCurReq to I_MAP, and assign I_Result = 5 to indicate an abnormal situation, and the ratio is I_Ratio = calculated value;

[0050] Judge the charging request current look-up table result of the current battery management system through the result I_Result and I_Ratio. By reading the result signal value I_Result, it can be clear that the charging request current value sent by the current battery management system is for MAP charging, vehicle limit value charging, charger limit value charging, or other charging restricted by the limit level ratio. Through I_Ratio, the ratio can be known according to the duty cycle limit, and the result is clear at a glance.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A charging request current testing method for a battery management system, characterized in that: The steps include: S1. Obtaining the single cell parameters sent by the battery management system, including: the maximum cell voltage Vcell_max or the actual SOC value, the maximum cell temperature Tmax, and the minimum cell temperature Tmin; S2, based on Vcell_max or SOC value and Tmax, Tmin in the charging current MAP table of the battery charging characteristics, respectively look up the maximum temperature current I_MAP_Tmax and the minimum temperature current I_MAP_Tmin, and take the smaller value of the two as the target table lookup current I_MAP; S3. Obtain the external system limit parameters, including the charging pile limit current I_CharStaLimit and the vehicle limit current I_VehicleLimit; S4, reading the current charging request current value CharCurReq sent by the battery management system; S5. Compare the relationships among I_MAP, I_CharStaLimit, I_VehicleLimit and CharCurReq respectively, and determine whether the current charging request is: a. Restrictions on charging stations; b. Vehicle restrictions; c. According to the MAP table request: I_MAP≈CharCurReq, d. Limit requests according to the ratio: I_MAP≈CharCurReq×ratio, e. Abnormal request; S6. Output a set of test judgment signals according to the judgment result, including the request status result value I_Result and the proportion coefficient I_Ratio, to quickly judge the source and limit level of the charging request current.

2. A charging request current testing method for a battery management system according to claim 1, characterized in that: In step S5, when CharCurReq≈I_CharStaLimit (error ±1A) and I_MAP is greater than I_CharStaLimit, it indicates that the charging pile is limited, and the value I_Result=6 is assigned at this time.

3. A charging request current testing method for a battery management system according to claim 1, characterized in that: In step S5, when CharCurReq≈I_VehicleLimit (error ±1A), and I_MAP is greater than I_VehicleLimit, it indicates that the entire vehicle is limited, and I_Result=7 is assigned.

4. A charging request current testing method for a battery management system according to claim 1, characterized in that: In step S5, after determining the charging pile restriction and the vehicle restriction, the MAP table request is determined. When I_MAP and CharCurReq are equal within the ±2A error range, it is determined that there is no restriction and charging is performed according to MAP. At this time, I_Result=1 and I_Ratio=1 are assigned.

5. A charging request current testing method for a battery management system according to claim 4, characterized in that: According to the MAP table request, when I_MAP is equal to CharCurReq×0.8 within the ±2A error range, it is determined to limit level 1 charging. At this time, the values ​​I_Result=1 and I_Ratio=0.8 are assigned.

6. A charging request current testing method for a battery management system according to claim 4, characterized in that: According to the MAP table request, when I_MAP is equal to CharCurReq×0.6 within the ±2A error range, it is determined to limit level 2 charging. At this time, the values ​​of I_Result=2 and I_Ratio=0.6 are assigned.

7. A charging request current testing method for a battery management system according to claim 4, characterized in that: According to the MAP table request, when I_MAP is equal to CharCurReq×0.3 within the ±2A error range, it is determined to limit level 3 charging. At this time, the values ​​I_Result=3 and I_Ratio=0.3 are assigned.

8. A charging request current testing method for a battery management system according to claim 4, characterized in that: When CharCurReq=0A, it means that the charging current is limited to 0A. At this time, the values ​​of I_Result=4 and I_Ratio=0 are assigned.

9. A charging request current testing method for a battery management system according to any one of claims 4 to 8, characterized in that: When the proportional relationship between I_MAP and CharCurReq is not satisfied, it indicates an abnormal request, and the ratio is calculated to set I_Result=5, where I_Ratio is the calculated ratio.

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