A method for judging and automatically correcting temperature acquisition failure

Abstract

The application relates to a method for judging and automatically correcting temperature collection faults, which comprises the following steps: S1, a battery management system calls a temperature collection module, records a highest or lowest temperature value T1 and a position thereof according to battery temperature information collected by the temperature collection module, and records another normal battery temperature information in the same module as T2; whether a difference between the highest or lowest temperature value T1 and T2 is greater than a second temperature threshold B is judged, if yes, a temperature sampling abnormality is reported, and calculation is entered, real capacitor impedance Rc of a detection circuit in the temperature collection module and a real resistance value T1_R of T1 are obtained by conversion according to a resistance sampling voltage division formula; a real temperature value T3 is obtained by table lookup according to an RT table, and T3 is used to replace T1. The real reaction of the battery internal thermal runaway condition is ensured to guarantee the personal safety, the automatic correction is performed again after the untrustworthiness, and the temperature can be correctly collected.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery management, in particular to a method for judging and automatically correcting temperature collection failure. BACKGROUND

[0002] The most important component in new energy vehicles is the power battery. Monitoring the actual temperature inside the power battery not only ensures the accuracy of SOC, SOF, SOE and charge / discharge current, but also ensures the real situation of the power battery and accurately feeds back thermal runaway, thereby protecting personal safety.

[0003] Currently, in new energy vehicles, the method for collecting the temperature of the power battery inside the power battery system is to arrange a certain specification of thermistor on the positive and negative aluminum bars of the battery. According to the different temperature coefficients, it is divided into positive temperature coefficient thermistor (PTC) and negative temperature coefficient thermistor (NTC). The resistance value of the thermistor is sent to the battery management system in real time through the low-voltage loop. The battery management system obtains the battery temperature by looking up the RT table. However, this collection method only has real-time collection function and cannot confirm the authenticity and reliability of the temperature at this time, and has no correction function.

[0004] For example, Figure 1 For the existing NTC detection circuit, the impedance of the front-end ESD capacitor C6049 part (capacitor body or peripheral substance) occasionally decreases or when the ESD capacitor voltage is insufficient, the ESD capacitor is broken down, the capacitor loses its capacitance characteristics and becomes a resistor, causing the resistance value of the NTC detection loop to change. In the case where the normal NTC is not failed, the overall resistance value of the measurement resistance circuit changes, causing temperature drift. The system cannot determine whether the temperature T at this time is correct or incorrect. The temperature rise or drop is directly reported to the battery management system, and the battery management system misreports, causing misjudgment of the product. SUMMARY

[0005] Therefore, it is necessary to provide a method for judging and automatically correcting temperature collection failure in view of the above problems.

[0006] A method for judging and automatically correcting temperature collection failure, comprising the following steps,

[0007] S1, the battery management system calls the temperature collection module, and records the highest or lowest temperature value T1 and its position according to the battery temperature information collected by the temperature collection module;

[0008] S2, according to the position of the highest or lowest temperature value T1, find another normal battery temperature information in the same module, and record it as T2;

[0009] S3, determine whether the difference between the highest or lowest temperature value T1 and T2 is greater than the second temperature threshold B. If not, return to S1; if yes, proceed to S4.

[0010] S4, report temperature sampling anomaly, record T1 as the abnormal temperature, and record its location;

[0011] S5, enter the calculation, and calculate the capacitance impedance Rc and the actual resistance value T1_R of the detection circuit in the temperature acquisition module according to the resistance sampling voltage division formula;

[0012] S6 retrieves the actual temperature value T3 from the RT table, replaces T1 with T3, and participates in the operation of various functions in the battery management system.

[0013] Preferably, in step S1, the battery management system determines whether the highest or lowest temperature value T1 collected occurs within X ms, and whether the temperature change difference Tx within X ms is greater than the first temperature threshold A. If yes, proceed to step S2; otherwise, re-call the temperature acquisition module to collect the temperature.

[0014] Preferably, Xms is 10 to 500 ms.

[0015] Preferably, the first temperature threshold A is 15 degrees Celsius, and the second temperature threshold B is 10 degrees Celsius.

[0016] Preferably, the operation flow of S5 is as follows:

[0017] S5.1, according to the resistor sampling voltage divider formula T2_VAd=VREF2_Out*R , and / (R , +R , and);

[0018] S5.2, reverse-engineer the resistance value R of the filter capacitor impedance and the thermistor connected in parallel at temperature T2. , AND = T2_VAd*R , / (VREF2_Out-T2_VAd);

[0019] S5.3, based on the changed T1_VAd=VREF2_Out*Rparallel / (R+Rparallel), obtain the resistance value Rparallel=T1_VAd*R / (VREF2_Out-T1_VAd) corresponding to temperature point T1.

[0020] S5.4, Obtain the capacitor impedance, R , c = R , and *T2_R / (T2_R–R) , and);

[0021] S5.5, according to the calculated fixed value Rc=R , c=T2_VAd*R , *T2_R / [(VREF2_Out-T2_VAd)*(T2_R–R , c], since the T2 temperature value is reliable, T2_VAd and T2_R are trusted values;

[0022] S5.6, R and is the formula R , c=R and*T1_R / (T1_R–R and) and the calculated fixed value Rc, the real T1_R=R and*Rc / | (Rc–R and) | is obtained, then the real temperature T3 is calculated according to the T1_R resistance value and the temperature RT table, the diagnosed abnormal temperature T1 is replaced by T3, and participates in the operation of each function of the battery management system;

[0023] T1_VAd is the voltage value through the temperature point T1 thermistor, and T2_VAd is the voltage value through the temperature point T2 thermistor;

[0024] VREF2_Out is the voltage of the power supply;

[0025] R, R , is a pull-up resistor, Rc, R , c is a filter capacitor impedance, a fixed value R=R , , a fixed value Rc=R , c;

[0026] T1_R and T2_R are composed of NTC thermistors;

[0027] R and is a resistance value composed of a temperature point T1 filter capacitor impedance and a thermistor in parallel, R , and is a resistance value composed of a temperature point T2 filter capacitor impedance and a thermistor in parallel.

[0028] The present application has the advantages that when the temperature of the battery abnormally changes, it can first determine whether the temperature at this time is reliable, ensure that the real reaction of the battery internal thermal runaway situation protects the personal safety of personnel, and then automatically corrects when it is not reliable, ensures that the temperature can be correctly collected, and the battery management system functions such as SOC, SOF, SOE and charge and discharge current can normally and reliably operate. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is an existing NTC detection circuit;

[0030] Figure 2 is a method flow chart for judging and automatically correcting temperature collection failure;

[0031] Figure 3 The equivalent circuit for NTC detection. DETAILED DESCRIPTION

[0032] In order to make the above objectives, features and advantages of the present application more clear and comprehensible, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the following description, a lot of specific details are set forth in order to provide a thorough understanding of the present application. However, the present application can be implemented in many different ways other than the ways described herein, and one of ordinary skill in the art can make similar improvements without departing from the spirit and scope of the present application, and therefore the present application is not limited to the specific embodiments disclosed below.

[0033] It should be noted that when an element is referred to as being "on" or "connected to" another element, it can be directly on the other element or intervening elements can also be present. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or intervening elements can also be present. The terms "vertical", "horizontal", "left", "right" and similar expressions as used herein are for the purpose of illustration only and are not intended to limit the present application.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0035] As shown in Figures 1 to 3 A method for judging and automatically correcting temperature acquisition failure, comprising the following steps,

[0036] S1, the battery management system calls the temperature acquisition module, judges whether the temperature change difference Tx appearing within X ms is greater than the first temperature threshold A according to the battery temperature information collected by the temperature acquisition module, records the highest or lowest temperature value T1 and its position, if yes, enters S2 and records the highest or lowest temperature value T1 and its position, if not, re-calls the temperature acquisition module to collect the temperature;

[0037] S2, according to the position of the highest or lowest temperature value T1, find another normal battery temperature information in the same module, record as T2.

[0038] Specifically, when the battery management system obtains the temperature change of the battery temperature collected by the temperature collection module within a short time X ms, which exceeds the first temperature threshold A, in the embodiment, the first temperature threshold A is 15 degrees Celsius, and in other embodiments, other temperature values of the first temperature threshold A can also be set according to the battery type, temperature control platform, cooling method and other reference factors, as long as A is greater than 15 degrees Celsius. The highest or lowest temperature value T1, at this time, the battery management system records the highest or lowest temperature T1 and its position, and X ms is 10-500 ms. For example Figure 1 The existing NTC detection circuit is used, that is, the negative temperature thermistor is used for temperature collection of the battery. In other embodiments, a positive temperature coefficient thermistor can also be used for temperature collection, and the collection method is the same. In this embodiment, NTC is used as an example for method description, and PTC is the same. Therefore, no further description is given here.

[0039] S3, determine whether the difference between the highest or lowest temperature value T1 and T2 is greater than the second temperature threshold B, specifically in this embodiment, the second temperature threshold B is 10 degrees Celsius, and in other embodiments, other temperature values of the second temperature threshold B can also be set according to the battery type, temperature control platform, cooling method and other reference factors, as long as B is greater than 10 degrees Celsius. If not, return to S1, if yes, enter S4. It should be noted that the battery pack is composed of a plurality of module series and parallel connection, each module has a plurality of single batteries in series and parallel connection, and the temperature information T2 in the same module is determined to compare and determine whether the temperature change difference of the module is normal, thereby improving the accuracy.

[0040] S4, report temperature sampling exception, record in the memory of the battery management system, record T1 as the abnormal temperature, and record the occurrence position of the abnormal temperature, and mark the module information of the battery in the battery pack.

[0041] S5, enter operation, and calculate the real resistance value T1_R of the capacitor impedance Rc of the detection circuit in the temperature collection module according to the resistance sampling voltage division formula. Specifically, as shown in Figure 1 As shown in the figure, the impedance of the current front-end ESD capacitor C6049 part (capacitor body or peripheral substance) is incidentally reduced or when the ESD capacitor voltage is insufficient, the ESD capacitor is broken down, the capacitor loses the capacitor characteristics and becomes a resistor, causing the resistance value of the NTC detection circuit to change. At this time, it is necessary to recalculate the circuit resistance value in the detection circuit, and the calculation method is to use the resistance sampling voltage division formula, which is the existing calculation method, and no further description is given here. At the same time, because the capacitor is broken down, the capacitor impedance Rc in the detection circuit needs to be recalculated, and Rc can obtain T1_R.

[0042] S6, according to the RT table lookup, the real temperature value T3 is obtained, T3 is used to replace T1, and participates in the operation of each function of the battery management system. Specifically, according to the RT table, T1_R is used for table lookup, the real temperature value T3 of the time period is obtained, T3 is used to replace T1, participates in the operation, prevents the battery management system from misjudging, has no influence on SOC, SOF, SOE and charging and discharging current and no trigger high temperature alarm and thermal runaway, and the vehicle power is still the whole vehicle.

[0043] In this embodiment, the operation process of S5 is as follows,

[0044] S5.1, according to the resistance sampling voltage division formula T2_VAd=VREF2_Out*R , and / (R , +R , and);

[0045] S5.2, the resistance value of the parallel connection of the filter capacitor impedance and the thermistor corresponding to the T2 temperature point is obtained by back calculation, R , and=T2_VAd*R , / (VREF2_Out-T2_VAd);

[0046] S5.3, according to the changed T1_VAd=VREF2_Out*R and / (R+R and), the resistance value R and of the parallel connection of the filter capacitor impedance and the thermistor corresponding to the T1 temperature point is obtained, R and=T1_VAd*R / (VREF2_Out-T1_VAd);

[0047] S5.4, the capacitor impedance R , c=R , and*T2_R / (T2_R–R , and) is obtained;

[0048] S5.5, according to the fixed value Rc=R , c=T2_VAd*R , *T2_R / [(VREF2_Out-T2_VAd)*(T2_R–R , and)], since the T2 temperature value is reliable, T2_VAd and T2_R are trusted values;

[0049] S5.6, R and is obtained by the formula R , c=R and*T1_R / (T1_R–R and) of the parallel connection of the capacitor impedance Rc and the temperature T1 impedance, and the fixed value Rc obtained by calculation, the real T1_R=R and*Rc / | (Rc–R and) | is obtained, then the real temperature T3 is calculated according to the T1_R resistance value and the temperature RT table, the diagnosed abnormal temperature T1 is replaced by T3, and participates in the operation of each function of the battery management system.

[0050] T1_VAd is the voltage value of the temperature point T1 thermistor, and T2_VAd is the voltage value of the temperature point T2 thermistor;

[0051] VREF2_Out is the voltage of the power supply;

[0052] R, R , is a pull-up resistor, Rc, R , c is a filter capacitor impedance, a fixed value R=R , , a fixed value Rc=R , c;

[0053] T1_R, T2_R are composed of NTC thermistors;

[0054] R is a resistance value composed of a temperature point T1 filter capacitor impedance and a thermistor in parallel, and R , is a resistance value composed of a temperature point T2 filter capacitor impedance and a thermistor in parallel.

[0055] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it cannot be understood as a limitation on the scope of the patent. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of protection of the present application. Therefore, the scope of protection of the present application patent should be subject to the appended claims.

Claims

1. A method of determining and automatically correcting temperature acquisition faults, characterized by: The method comprises the following steps: S1, the battery management system calls the temperature collection module, according to the battery temperature information collected by the temperature collection module, and records the highest or lowest temperature value T1 and its position; S2, according to the position of the highest or lowest temperature value T1, find another normal battery temperature information in the same module, record as T2; S3, judge whether the difference between the highest or lowest temperature value T1 and T2 is greater than the second temperature threshold B, if not, return to S1, if yes, enter S4; S4, report temperature sampling exception, record T1 as abnormal temperature and record its position; S5, enter operation, according to the resistance sampling voltage division formula, convert to obtain the capacitance impedance Rc of the detection circuit in the temperature collection module and the real resistance value T1_R of T1; S6, according to the RT table, obtain the real temperature value T3, use T3 to replace T1, participate in the operation of each function in the battery management system, The operation process of S5 is as follows, S5.1, according to the resistance sampling voltage divider formula T2_VAd = VREF2_Out * R , and (R , + R , ) ; S5.2, the T2 temperature point corresponds to the resistance of the parallel connection of the filter capacitor impedance and the thermistor, R , and = T2_VAd * R , (VREF2_Out - T2_VAd); S5.3, according to the changed T1_VAd=VREF2_Out*R and / (R+R and), obtain the resistance value R and of the filter capacitor impedance and thermistor parallel connection corresponding to the T1 temperature point= T1_VAd*R / (VREF2_Out-T1_VAd); S5.4, obtain the capacitive impedance, R , c = R , and T2_R / (T2_R - R , and); S5.5, according to the calculated fixed value Rc = R , c = T2_VAd * R , T2_R / [(VREF2_Out - T2_VAd) * (T2_R - R , and)], since the T2 temperature value is reliable, T2_VAd, T2_R are trusted values; S5.6, R and is the formula R obtained by parallel capacitor impedance Rc and temperature T1 impedance in parallel , c = R and * T1_R / (T1_R - R and ) and the calculated fixed value Rc, the real T1_R = R and * Rc / | (Rc - R and ) |, and then according to T1_R resistance and temperature RT table to calculate the real temperature T3, replace the diagnosed abnormal temperature T1 with T3, and let it participate in the battery management system function operation; T1_VAd is the voltage value through the temperature point T1 thermistor, T2_VAd is the voltage value through the temperature point T2 thermistor; VREF2_Out is the supply voltage; R, R , Rc, R , c is the filter capacitance impedance, a fixed value R = R , Rc = R , c; T1_R, T2_R are composed of NTC thermistor; R is the resistance value consisting of the parallel connection of the temperature point T1 filter capacitor impedance and the thermistor , R is the resistance value consisting of the parallel connection of the temperature point T2 filter capacitor impedance and the thermistor 2. The method for judging and automatically correcting temperature acquisition faults as described in claim 1, characterized in that: The S1, the battery management system judges whether the highest or lowest temperature value T1 collected is in Xms, and whether the temperature change difference Tx in Xms is greater than the first temperature threshold A, if yes, enter S2, if not, call the temperature collection module to collect temperature again.

3. The method of claim 2, wherein: the temperature collection failure is determined and automatically corrected by: determining if the temperature collection failure is due to a sensor failure; and if the temperature collection failure is due to a sensor failure, replacing the sensor. 5 The Xms is 10-500ms.

4. The method of claim 2, wherein: the temperature collection failure is determined and automatically corrected by: determining if the temperature collection failure is due to a sensor failure; and if the temperature collection failure is due to a sensor failure, replacing the sensor. 5 The first temperature threshold A is 15 degrees Celsius, and the second temperature threshold B is 10 degrees Celsius.

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