A signal acquisition method for new energy battery intelligent management system

Abstract

The present application relates to the field of battery thermal management technology, and specifically to a signal acquisition method for a new energy battery intelligent management system, the method comprising: obtaining the temperature signal of each conductive connecting piece in a standard battery pack and a battery pack to be tested at each moment; determining each heating period of each conductive connecting piece; determining the battery state judgment factor to determine whether the battery is in a normal charge and discharge state; determining the battery temperature difference index of the battery pack to be tested to determine whether there is a fault in the new energy battery pack; obtaining the fused temperature signal of the battery pack to be tested at each moment, and using a prediction model algorithm to predict the battery temperature at the next moment, and thermally managing the new energy battery. Thereby improving the accuracy of temperature management of new energy batteries, further improving the control accuracy of the temperature of new energy batteries, and helping to increase battery life.

Description

Technical Field

[0001] The present application relates to the technical field of battery thermal management, and in particular to a signal acquisition method for an intelligent management system of a new energy battery. Background Art

[0002] With the global focus on sustainable energy and reducing greenhouse gas emissions, the demand for electric vehicles using new energy sources has grown rapidly, thus driving the research of new energy batteries, especially lithium-ion batteries. The intelligent management system of new energy batteries is a key technology to ensure the safe operation of batteries and optimize battery performance. It is responsible for monitoring the status of batteries, including voltage, current, temperature, etc., and executing necessary control strategies. By collecting key parameter signals of batteries, it is possible to prevent overcharging or overdischarging of batteries, balance control and fault diagnosis.

[0003] In new energy batteries, a battery pack is composed of multiple battery cells, which are connected in series or in parallel by nickel conductive connecting plates to meet the required voltage and capacity. In the existing technology, the temperature of the battery connecting plate is usually collected instead of the temperature of the battery body. The battery management system uses this temperature to perform thermal management on the battery and perform operations such as heating, cooling or maintaining the current temperature of the battery. However, there are usually multiple battery cells in a battery pack, and the temperature of a conductive connecting plate is not enough to reflect the temperature changes of the entire battery pack. Directly using the temperature signal collected by a conductive connecting plate will make the battery's thermal management less accurate and affect the battery life. Summary of the invention

[0004] In order to solve the above technical problems, a signal acquisition method for a new energy battery intelligent management system is provided to solve the existing problems.

[0005] The solution to the technical problem of this application is to provide a signal acquisition method for a new energy battery intelligent management system, comprising the following steps:

[0006] Obtaining the temperature signal of each conductive connecting piece in the standard battery pack and the battery pack to be tested at each moment;

[0007] Determine each temperature rise period of each conductive connecting piece in the standard battery pack and the battery pack to be tested according to the change trend of the temperature signal of each conductive connecting piece at each moment;

[0008] Determine the battery state judgment factor of each conductive connecting piece of the battery pack to be tested in each heating period according to the difference in the heating time and temperature signal of each conductive connecting piece of the battery pack to be tested and the standard battery pack in each heating period, and judge whether the battery is in a normal charging and discharging state in each heating period;

[0009] If the battery pack to be tested is in a normal charging and discharging state during each temperature rise period, the battery temperature difference index of the battery pack to be tested is determined according to the temperature signal difference between each conductive connecting piece in the battery pack to be tested and the standard battery pack, and whether the new energy battery pack has a fault is judged;

[0010] If there is no fault in the battery pack to be tested, the temperature signals of each conductive connecting piece of the battery pack to be tested at each moment are fused to obtain the fused temperature signals of the battery pack to be tested at each moment, and the prediction model algorithm is used to predict the battery temperature at the next moment to perform thermal management on the new energy battery;

[0011] If the battery pack under test is not in a normal charging and discharging state during each temperature rise period or has a fault, the battery pack under test shall be repaired;

[0012] The step of determining the battery state judgment factor of each conductive connecting piece of the battery pack to be tested in each temperature rising period includes:

[0013] The shortest period among the temperature rising periods is recorded as the minimum charging period of each conductive connecting piece in the standard battery pack, and the longest period is recorded as the maximum discharging period of each conductive connecting piece in the standard battery pack;

[0014] Determine a time judgment threshold and a temperature judgment threshold of the standard battery pack according to the difference between the duration of the minimum charging period and the maximum discharging period of each conductive connecting piece of the standard battery pack and the temperature;

[0015] Determine the cumulative time difference and the cumulative temperature difference of each conductive connecting piece of the battery pack to be tested in each heating period according to the time length and the temperature signal difference of each conductive connecting piece of the battery pack to be tested in each heating period;

[0016] Based on the time accumulation difference and the time judgment threshold, determining the time judgment index of each conductive connecting piece of the battery pack to be tested in each heating period, wherein the time judgment index is negatively correlated with the time accumulation difference and the time judgment threshold respectively;

[0017] The temperature judgment index of each conductive connecting piece of the battery pack to be tested in each heating period is negatively correlated with the temperature cumulative difference and the temperature judgment threshold value;

[0018] The battery state judgment factor of each conductive connecting piece of the battery pack to be tested in each temperature rising period is positively correlated with the time judgment index and the temperature judgment index respectively;

[0019] The step of determining the battery temperature difference index of the battery pack to be tested and judging whether the new energy battery pack has a fault includes:

[0020] Determine the standard temperature difference of the standard battery pack at each moment in the heating period and the temperature difference to be measured of the battery pack to be tested at each moment in the heating period according to the difference of the temperature signals at each moment between each conductive connecting piece of the standard battery pack and the battery pack to be tested;

[0021] Determining the relative temperature difference of the battery pack to be tested at each moment in the heating period based on the standard temperature difference and the temperature difference to be tested;

[0022] The battery temperature difference index of the battery pack to be tested is positively correlated with the relative temperature difference at all times;

[0023] If the battery temperature difference index is less than or equal to the preset temperature threshold, the battery pack to be tested does not have a fault; otherwise, the battery pack to be tested does have a fault.

[0024] Preferably, the step of determining the temperature rise time periods of each conductive connecting piece in the standard battery pack and the battery pack to be tested comprises:

[0025] Constructing a temperature difference sequence of each conductive connecting piece in a standard battery pack at each time period;

[0026] The sum of all elements in the temperature difference sequence is recorded as the cumulative difference of the temperature change sequence in each period;

[0027] If the cumulative difference is less than 0, the time period corresponding to the temperature change sequence is recorded as the cooling time period of each conductive connecting piece of the standard battery pack; if the cumulative difference is equal to 0, it is recorded as the dormancy time period of each conductive connecting piece of the standard battery pack; if the cumulative difference is greater than 0, it is recorded as the heating time period of each conductive connecting piece of the standard battery pack;

[0028] The same acquisition method as that of each conductive connecting piece of a standard battery pack is adopted to obtain each cooling period, each dormant period and each heating period of each conductive connecting piece of the battery pack to be tested.

[0029] Preferably, the method for constructing the temperature difference sequence of each time period of each conductive connecting piece is:

[0030] The peaks and troughs of the temperature signal at all times for each conductive connecting piece in a standard battery pack;

[0031] According to the peaks and troughs, the temperature signal of each conductive connecting piece at all times is divided into a plurality of time periods;

[0032] All temperature signals in each time period are combined into a temperature change sequence of each time period;

[0033] The first-order difference result of the temperature change sequence is used to obtain the temperature difference sequence of each conductive connecting piece in each time period.

[0034] Preferably, the step of determining the time judgment threshold and the temperature judgment threshold of the standard battery pack includes:

[0035] The average of the minimum charging time periods of all the conductive connecting pieces of the standard battery pack is recorded as the charging time threshold;

[0036] The average of the maximum discharge time periods of all the conductive connecting pieces of the standard battery pack is recorded as the discharge time threshold;

[0037] Determining a time judgment threshold of a standard battery pack according to a difference between the charging time threshold and the discharging time threshold;

[0038] The temperature judgment threshold of the standard battery pack is obtained by adopting the same method as the time judgment threshold for the temperature signals of the minimum charging period and the maximum discharging period of all the conductive connecting pieces of the standard battery pack.

[0039] Preferably, the step of determining the cumulative time difference and the cumulative temperature difference of each conductive connecting piece of the battery pack to be tested in each heating period includes:

[0040] Calculate the time length of each conductive connecting piece of the battery pack to be tested in each heating period, and record it as the average time length of each conductive connecting piece to be tested in each heating period;

[0041] Taking the difference between the average duration to be measured and the charging duration threshold as the first time difference;

[0042] Taking the difference between the average time length to be measured and the discharge time length threshold as the second time difference;

[0043] The sum of the first time difference and the second time difference is used as the cumulative time difference of each conductive connecting piece of the battery pack to be tested in each heating period;

[0044] For the temperature signal of each conductive connecting piece of the battery pack to be tested in each heating period, the same method as the time cumulative difference is adopted to obtain the temperature cumulative difference of each conductive connecting piece of the battery pack to be tested in each heating period.

[0045] Preferably, the determining of the standard temperature difference of the standard battery pack at each time in the heating period and the temperature difference to be measured of the battery pack to be measured at each time in the heating period includes:

[0046] Determine the temperature signal difference of each conductive connecting piece at each moment in the heating period according to the difference of the temperature signals of any two conductive connecting pieces of the standard battery pack at the same moment in the heating period;

[0047] The standard temperature difference of the standard battery pack at each moment in the heating period is positively correlated with the temperature signal difference of all the conductive connecting sheets at each moment in the heating period;

[0048] For the temperature signal of each conductive connecting piece of the battery pack to be tested at each moment in the heating period, the same method as the standard temperature difference is adopted to obtain the temperature difference to be tested at each moment in the heating period of the battery pack to be tested.

[0049] Preferably, the step of determining the relative temperature difference of the battery pack to be tested at each time point in the temperature rising period includes:

[0050] The temperature difference thresholds are respectively positively correlated with the standard temperature differences at all moments in the heating period;

[0051] The difference between the temperature difference to be measured of the battery group to be tested at each moment in the heating period and the temperature difference threshold is determined as the relative temperature difference of the battery group to be tested at each moment in the heating period.

[0052] Preferably, the method for acquiring the fusion temperature signal of the battery pack to be tested at each moment is:

[0053] For each moment during the temperature rise period of the battery pack to be tested, the maximum temperature signal of all the conductive connecting pieces at the same moment is used as the fusion temperature signal at each moment;

[0054] For each moment during the cooling period of the battery pack to be tested, the minimum temperature signal of all the conductive connecting pieces at the same moment is used as the fusion temperature signal at each moment;

[0055] For each moment in the dormant period of the battery pack to be tested, the average temperature signal of all the conductive connecting sheets at the same moment is used as the fusion temperature signal at each moment.

[0056] This application has at least the following beneficial effects:

[0057] The present application determines the cooling periods, dormancy periods and heating periods of each conductive connecting piece in the standard battery pack and the battery pack to be tested by analyzing the changing trend of the temperature signal of each conductive connecting piece at each moment. The beneficial effect of the application is that the heating periods of the new energy battery pack during the charging and discharging process are distinguished, which is conducive to the subsequent analysis of abnormal conditions of battery temperature rise. The battery state judgment factor of each heating period is determined by comparing the heating time and temperature difference of each conductive connecting piece of the battery pack to be tested and the standard battery pack. The beneficial effect of the application is that the normal charging and discharging periods during the heating process of the new energy battery are distinguished, which is conducive to further step analysis; determine the battery temperature difference index according to the temperature difference between the conductive connecting pieces, which has the beneficial effect of analyzing whether there is abnormal temperature in the battery pack in the normal charging and discharging state, judging whether there is a fault in the new energy battery pack, and facilitating timely maintenance; fuse the temperature signal of each conductive connecting piece at each moment, adopt the prediction model algorithm to predict the battery temperature at the next moment, control and start the heat dissipation device or heating device in advance, and perform thermal management on the new energy battery, which has the beneficial effect of improving the accuracy of temperature management of new energy batteries, further improving the control accuracy of temperature of new energy batteries, and helping to increase battery life. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] The following is a further detailed description of a signal acquisition method for a new energy battery intelligent management system of the present application in conjunction with the accompanying drawings.

[0059] Figure 1 A flowchart of a signal acquisition method for a new energy battery intelligent management system provided in this application;

[0060] Figure 2 A flowchart of the steps of a method for obtaining a battery state judgment factor of each conductive connecting piece of a battery pack to be tested in each heating period provided by the present application;

[0061] Figure 3 A flowchart of the steps of a method for obtaining a battery temperature difference index of a battery pack to be tested provided in the present application. DETAILED DESCRIPTION

[0062] In order to make the purpose, technical solution and advantages of this application more clear, the following is a further detailed description of a signal acquisition method for a new energy battery intelligent management system proposed in this application in conjunction with the accompanying drawings and implementation examples. It should be understood that the specific embodiments described herein are only used to explain this application and are not used to limit this application.

[0063] Unless defined otherwise, 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.

[0064] See also Figure 1 , which shows a flowchart of a signal acquisition method for a new energy battery intelligent management system provided by an embodiment of the present application, the method comprising the following steps:

[0065] Step 1: Obtain the temperature signal of each conductive connecting piece in the standard battery pack and the battery pack to be tested at each moment.

[0066] The working process of the new energy battery thermal management system is to control the heat dissipation or heating equipment through the battery temperature signal. When the battery temperature is higher than the high temperature threshold, the heat dissipation device is started to lower the battery temperature; similarly, when the battery temperature is lower than the low temperature threshold, the heating device is started to increase the battery temperature; when the battery temperature is between the high temperature threshold and the low temperature threshold, no operation is performed to maintain the normal operation of the battery.

[0067] The temperatures of multiple conductive connecting pieces in a standard battery pack that has not undergone quality inspection and has no faults during each charging and discharging process are collected, wherein a temperature sensor is placed on the conductive connecting piece, and accordingly, the temperatures of the battery pack to be tested during the charging and discharging process are collected, and the collection time interval is t, wherein both charging and discharging are full charging and full discharging without stopping halfway, and the temperature signal output by the temperature sensor is obtained, and the temperature signal is preprocessed to obtain the temperature signal of each conductive connecting piece of the standard battery pack and the battery pack to be tested at each moment.

[0068] Preferably, as an embodiment of the present application, the temperatures of the three conductive connecting plates in the standard battery pack and the battery pack to be tested during 50 charging and discharging processes are collected respectively, and the collection time interval is 5 minutes. Among them, the temperatures of the three conductive connecting plates at the upper left corner, the center and the lower right corner of the new energy battery pack are collected at each moment, and the temperature signal is Gaussian filtered to remove noise, so as to obtain the temperature signal of each conductive connecting plate of the standard battery pack and the battery pack to be tested at each moment.

[0069] At this point, the temperature signals of each conductive connecting piece of the standard battery pack and the battery pack to be tested are obtained at each moment.

[0070] Step 2: determine the temperature rise time periods of each conductive connecting piece in the standard battery pack and the battery pack to be tested according to the change trend of the temperature signal of each conductive connecting piece at each moment.

[0071] New energy batteries will generate heat whether they are in the charging or discharging state, causing the battery temperature to rise. In the dormant state when the battery is not working, the battery temperature is usually consistent with the ambient temperature. This is because whether it is the conversion of electrical energy into chemical energy during charging or the conversion of chemical energy into electrical energy during discharging, there will be energy loss, which will be converted into heat energy and dissipated, causing the battery temperature to rise. Therefore, whether it is in the charging or discharging state, the battery temperature signal is significantly different from that in the dormant state.

[0072] For the temperature signal of each conductive connecting piece in the standard battery pack at all times, all peaks and valleys of each conductive connecting piece are obtained;

[0073] Preferably, as an embodiment of the present application, a local extremum method is used to obtain all the peaks and troughs of each conductive connecting piece, wherein the local extremum method is a well-known technology and will not be described in detail in this embodiment.

[0074] It is understandable that the peaks and troughs of a set of data are obtained by not only using the local extreme value method, but also other methods of the prior art, such as the derivative method, the quadratic difference method, etc., as other implementation methods, and this embodiment does not limit this.

[0075] According to the peaks and troughs, the temperature signal of each conductive connecting piece at all times is divided into a plurality of time periods;

[0076] All temperature signals in each time period are combined into a temperature change sequence of each time period;

[0077] The result of the first-order difference of the temperature change sequence is used to obtain a temperature difference sequence;

[0078] The sum of all elements in the temperature difference sequence is recorded as the cumulative difference of the temperature change sequence in each period;

[0079] If the cumulative difference is less than 0, the time period corresponding to the temperature change sequence is recorded as the cooling time period of each conductive connecting piece of the standard battery pack; if the cumulative difference is equal to 0, it is recorded as the dormancy time period of each conductive connecting piece of the standard battery pack; if the cumulative difference is greater than 0, it is recorded as the heating time period of each conductive connecting piece of the standard battery pack;

[0080] For the temperature signals of each conductive connecting piece of the battery pack to be tested at all times, the same acquisition method as that of each cooling period, each sleep period and each heating period of each conductive connecting piece of the standard battery pack is adopted to obtain each cooling period, each sleep period and each heating period of each conductive connecting piece of the battery pack to be tested.

[0081] It should be noted that if each element in the temperature difference sequence is greater than zero, the battery temperature is on an upward trend; if each element in the temperature difference sequence is less than zero, the battery temperature is on a downward trend. When the battery temperature is on a downward trend, it means that the battery is not in a charging or discharging state; if the downward trend is greater than the upward trend, that is, the cumulative difference is less than zero, it means that the period is not a charging or discharging or charging period.

[0082] So far, the temperature rise time periods of each conductive connecting piece of the standard battery pack and the battery pack to be tested are obtained.

[0083] Step 3, according to the difference in the heating time and temperature signal of each conductive connecting piece of the battery pack to be tested and the standard battery pack in each heating period, determine the battery state judgment factor of each conductive connecting piece of the battery pack to be tested in each heating period, and judge whether the battery is in a normal charging and discharging state in each heating period.

[0084] Furthermore, the change in the battery state is a basis for judging whether the conductive connecting piece contains abnormal data. First, the temperature change of the battery in the charging or discharging state is used to judge whether the battery is in the charging or discharging state. When the battery is not in the charging or discharging state, the temperature rise can be considered as abnormal data. When the battery is in the charging and discharging state, whether the temperature rise is abnormal data needs to be further calculated and judged in combination with the temperature change of other conductive connecting pieces. The specific method is:

[0085] The shortest period among the temperature rising periods is recorded as the minimum charging period of each conductive connecting piece in the standard battery pack, and the longest period is recorded as the maximum discharging period of each conductive connecting piece in the standard battery pack;

[0086] It should be noted that, because the charging time is usually shorter than the discharging time, if the length of a certain period is less than the minimum charging period or greater than the maximum discharging period, abnormal temperature may exist.

[0087] The average of the minimum charging time periods of all the conductive connecting pieces of the standard battery pack is recorded as the charging time threshold;

[0088] The average of the maximum discharge time periods of all the conductive connecting pieces of the standard battery pack is recorded as the discharge time threshold;

[0089] Determining a time judgment threshold according to a difference between the charging time threshold and the discharging time threshold;

[0090] Preferably, as an embodiment of the present application, the time judgment threshold is the difference between the charging duration threshold and the discharging duration threshold.

[0091] The average value of the temperature signals of the minimum charging period of all the conductive connecting pieces of the standard battery pack is recorded as the charging temperature threshold;

[0092] The average value of the temperature signals of all the conductive connecting pieces of the standard battery pack during the maximum discharge period is recorded as the discharge temperature threshold;

[0093] determining a temperature judgment threshold according to a difference between the charging temperature threshold and the discharging temperature threshold;

[0094] Preferably, as an embodiment of the present application, the temperature judgment threshold is the difference between the charging temperature threshold and the discharging temperature threshold.

[0095] Calculate the time length of each conductive connecting piece of the battery pack to be tested in each heating period, and record it as the average time length of each conductive connecting piece to be tested in each heating period;

[0096] Taking the difference between the average duration to be measured and the charging duration threshold as the first time difference;

[0097] Taking the difference between the average time length to be measured and the discharge time length threshold as the second time difference;

[0098] The sum of the first time difference and the second time difference is used as the cumulative time difference of each conductive connecting piece of the battery pack to be tested in each heating period;

[0099] Preferably, as an embodiment of the present application, the first time difference is the absolute value of the difference between the average time to be measured and the charging time threshold; secondly, the second time difference is the absolute value of the difference between the average time to be measured and the discharging time threshold.

[0100] Calculate the average value of the temperature signal of each conductive connecting piece of the battery pack to be tested in each heating period, and record it as the average temperature to be tested of each conductive connecting piece in each heating period;

[0101] taking the difference between the average temperature to be measured and the charging temperature threshold as a first temperature difference;

[0102] taking the difference between the average temperature to be measured and the discharge temperature threshold as a second temperature difference;

[0103] The sum of the first temperature difference and the second temperature difference is taken as the cumulative temperature difference of each conductive connecting piece of the battery pack to be tested in each heating period; preferably, as an embodiment of the present application, the first temperature difference is the absolute value of the difference between the average temperature to be measured and the charging temperature threshold; secondly, the second temperature difference is the absolute value of the difference between the average temperature to be measured and the discharge temperature threshold.

[0104] Based on the time accumulation difference and the time judgment threshold, determining the time judgment index of each conductive connecting piece of the battery pack to be tested in each heating period, wherein the time judgment index is negatively correlated with the time accumulation difference and the time judgment threshold respectively;

[0105] Based on the temperature cumulative difference and the temperature judgment threshold, determining a temperature judgment index of each conductive connecting piece of the battery pack to be tested in each heating period, wherein the temperature judgment index is negatively correlated with the temperature cumulative difference and the temperature judgment threshold respectively;

[0106] It can be understood that a negative relationship indicates that the dependent variable will decrease as the independent variable increases, and the dependent variable will increase as the independent variable decreases. The specific relationship can be a subtraction relationship, a division relationship, a negative exponential power, etc., which is determined by actual application and this application does not impose any special restrictions on this.

[0107] Preferably, as an embodiment of the present application, the difference between the time cumulative difference and the time judgment threshold is used as the time judgment index of each conductive connecting piece of the battery pack to be tested in each heating period; the difference between the temperature cumulative difference and the temperature judgment threshold is used as the temperature judgment index of each conductive connecting piece of the battery pack to be tested in each heating period.

[0108] It should be noted that when the duration of a certain temperature rise period of the battery pack to be tested is within the normal time range, that is, between the minimum charging period and the maximum charging period, it is between the charging time threshold and the discharging time threshold, and the obtained time judgment index is 0.

[0109] Based on the time judgment index and the temperature judgment index, determining a battery state judgment factor of each conductive connecting piece of the battery pack to be tested in each temperature rising period, wherein the battery state judgment factor is positively correlated with the time judgment index and the temperature judgment index respectively;

[0110] It can be understood that a positive relationship means that the dependent variable will increase as the independent variable increases, and the dependent variable will decrease as the independent variable decreases. The specific relationship can be a multiplication relationship, an addition relationship, or the idempotence of an exponential function, which is determined by actual application and this application does not impose any special restrictions on this.

[0111] Preferably, as an embodiment of the present application, the sum of the time judgment index and the temperature judgment index is used as a battery state judgment factor of each conductive connecting piece of the battery pack to be tested in each temperature rising period.

[0112] It should be noted that the battery status judgment factor considers whether the temperature rise interval belongs to the charging and discharging state from two aspects. First, if the duration of each temperature rise period is not between the minimum charging period and the maximum charging period, the temperature rise period is considered to be abnormal. Similarly, the more the average temperature of the period deviates from the temperature judgment threshold, the more likely it is an abnormal temperature period; secondly, the larger the battery status judgment factor of each temperature rise period, the greater the difference between the duration of the period and the normal charging and discharging time, or the greater the difference with the normal charging and discharging temperature, the more likely the battery temperature rise in the period is caused by abnormality, and the battery pack needs to be tested. On the contrary, the period is more likely to be a normal charging and discharging state.

[0113] Furthermore, the present application provides a flowchart of the steps of the method for obtaining the battery state judgment factor of each conductive connecting piece of the battery pack to be tested in each heating period as shown in FIG. Figure 2 shown.

[0114] At this point, the battery state judgment factor of each conductive connecting piece of the battery pack to be tested in each temperature rising period is obtained.

[0115] Step 4: If the battery pack to be tested is in a normal charging and discharging state during each temperature rise period, the battery temperature difference index of the battery pack to be tested is obtained according to the temperature signal difference between each conductive connecting piece in the battery pack to be tested and the standard battery pack to determine whether the new energy battery pack has a fault.

[0116] Furthermore, if it is in a normal charge and discharge state, and it is still not possible to determine whether the temperature rise is caused by an abnormality, it can be compared with the temperature signals of the conductive connecting pieces at other locations. Since the temperature signal is obtained by the temperature sensor, and an abnormal temperature signal will be generated when the temperature sensor fails, the temperature rise that occurs when the battery is not charging or discharging may be caused by this reason. It is unreasonable to adjust the battery temperature according to the abnormal temperature signal, so it is necessary to compare the signals of several temperature sensors to eliminate abnormal temperature data. In addition, the conductive connecting piece in the battery may occasionally cause abnormal solder joints on the connecting piece due to problems with the welding process. Abnormal solder joints will increase the internal resistance of the battery, and will generate more heat when current passes through, causing the battery cell where it is located to heat up higher. By obtaining the battery temperature difference index, it is determined whether the normal temperature rise interval in the time range is caused by abnormal temperature. The specific method is:

[0117] Determine the temperature signal difference of each conductive connecting piece at each moment in the heating period according to the difference of the temperature signals of any two conductive connecting pieces of the standard battery pack at the same moment in the heating period;

[0118] Preferably, as an embodiment of the present application, the difference between the temperature signals of any two conductive connecting pieces of the standard battery pack at the same time in the heating period is used as the temperature signal difference of each conductive connecting piece at each time in the heating period;

[0119] The standard temperature difference of the standard battery pack at each moment in the heating period is positively correlated with the temperature signal difference of all the conductive connecting sheets at each moment in the heating period;

[0120] Preferably, as an embodiment of the present application, the average value of the temperature signal difference of all the conductive connecting pieces at the same time in the heating period is calculated to obtain the standard temperature difference of the standard battery pack at each time in the heating period;

[0121] For the temperature signal of each conductive connecting piece of the battery pack to be tested at each moment in the heating period, the same method as the standard temperature difference is adopted to obtain the temperature difference to be tested at each moment in the heating period of the battery pack to be tested;

[0122] The temperature difference thresholds are respectively positively correlated with the standard temperature differences at all moments in the heating period;

[0123] Preferably, as an embodiment of the present application, the average value of the standard temperature difference at all moments in the heating period is used as the temperature difference threshold.

[0124] It should be noted that due to the different arrangements of battery cells in the same battery pack, the temperature signals of different conductive connecting pieces at the same time will also be different. Specifically, the temperature of the peripheral battery cells is slightly lower than that of the central battery cells. Therefore, the temperature difference of the conductive connecting pieces at different positions is measured. The farther the temperature difference of the conductive connecting pieces at different positions of the battery pack to be tested is from the temperature difference threshold of the standard battery pack, the more likely it is that a fault is caused.

[0125] Determine the difference between the temperature difference of the battery pack to be tested at each moment in the heating period and the temperature difference threshold as the relative temperature difference of the battery pack to be tested at each moment in the heating period;

[0126] The battery temperature difference index of the battery pack to be tested is positively correlated with the relative temperature difference at all times;

[0127] Preferably, as an embodiment of the present application, the difference between the temperature difference to be measured and the temperature difference threshold is determined as the relative temperature difference of the battery group to be measured at each moment in the heating period; secondly, the battery temperature difference index of the battery group to be measured is the sum of the relative temperature differences at all moments.

[0128] If the battery temperature difference index is less than or equal to the preset temperature threshold, the battery pack to be tested does not have a fault; if the battery temperature difference index is greater than the preset temperature threshold, the battery pack to be tested has a fault;

[0129] Preferably, as an embodiment of the present application, the preset temperature threshold value is 5.

[0130] It should be noted that if the battery temperature difference index is greater than the preset temperature threshold, it is considered that there is an abnormal solder joint in a conductive connecting piece of the battery pack to be tested or an abnormal temperature sensor therein, and timely maintenance should be carried out to avoid battery failure.

[0131] Furthermore, the present application provides a flowchart of the steps of the method for obtaining the battery temperature difference index of the battery pack to be tested. Figure 3 shown.

[0132] At this point, the battery temperature difference index of the battery pack to be tested is obtained to determine whether the new energy battery pack has a fault.

[0133] Step 5: If there is no fault in the battery pack to be tested, the temperature signals of each conductive connecting piece of the battery pack to be tested at each moment are fused to obtain the fused temperature signals of the battery pack to be tested at each moment, and a prediction model algorithm is used to predict the battery temperature at the next moment to perform thermal management on the new energy battery.

[0134] The above steps have eliminated the abnormal temperature signal caused by abnormal conditions in the battery pack to be tested. Since the temperatures of different battery cells in a battery pack may vary, the temperature signal of only one conductive connecting piece is not enough to reflect the temperature of the battery pack. Therefore, the temperature signals of different conductive connecting pieces are merged. The specific method is as follows:

[0135] For each moment during the temperature rise period of the battery pack to be tested, the maximum temperature signal of all the conductive connecting pieces at the same moment is used as the fusion temperature signal at each moment;

[0136] For each moment during the cooling period of the battery pack to be tested, the minimum temperature signal of all the conductive connecting pieces at the same moment is used as the fusion temperature signal at each moment;

[0137] For each moment during the dormant period of the battery pack to be tested, the average temperature signal of all the conductive connecting pieces at the same moment is used as the fusion temperature signal at each moment;

[0138] Based on the fused temperature signal of the battery pack to be tested at each moment, a prediction model algorithm is used to predict the battery temperature at the next moment;

[0139] Preferably, as an embodiment of the present application, an EWMA exponentially weighted moving average algorithm is used to predict the battery temperature at the next moment.

[0140] It can be understood that this embodiment only provides a prediction model, namely the WMA exponential weighted moving average algorithm. As other implementation methods, the implementer can use other prediction models of the prior art to predict the battery temperature, such as the exponential smoothing algorithm and ARIMA algorithm in the time series model, and the decision tree in the machine learning model. This embodiment does not impose any special restrictions on this.

[0141] Based on the predicted battery temperature at the next moment, the heat dissipation device or heating device can be controlled and started in advance to avoid overheating or overcooling of the battery.

[0142] It should be understood that although Figure 1 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, Figure 1At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0143] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0144] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the present application. It should be pointed out that, for those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present application. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application without departing from the content of the technical solution of the present application, shall fall within the protection scope of the technical solution of the present application.

Claims

1. A signal acquisition method for a new energy battery intelligent management system, characterized in that: The method comprises the following steps: Obtaining the temperature signal of each conductive connecting piece in the standard battery pack and the battery pack to be tested at each moment; Determine each temperature rise period of each conductive connecting piece in the standard battery pack and the battery pack to be tested according to the change trend of the temperature signal of each conductive connecting piece at each moment; Determine the battery state judgment factor of each conductive connecting piece of the battery pack to be tested in each heating period according to the difference in the heating time and temperature signal of each conductive connecting piece of the battery pack to be tested and the standard battery pack in each heating period, and judge whether the battery is in a normal charging and discharging state in each heating period; If the battery pack to be tested is in a normal charging and discharging state during each temperature rise period, the battery temperature difference index of the battery pack to be tested is determined according to the temperature signal difference between each conductive connecting piece in the battery pack to be tested and the standard battery pack, and whether the new energy battery pack has a fault is judged; If there is no fault in the battery pack to be tested, the temperature signals of each conductive connecting piece of the battery pack to be tested at each moment are fused to obtain the fused temperature signals of the battery pack to be tested at each moment, and the prediction model algorithm is used to predict the battery temperature at the next moment to perform thermal management on the new energy battery; If the battery pack under test is not in a normal charging and discharging state during each temperature rise period or has a fault, the battery pack under test shall be repaired; The step of determining the battery state judgment factor of each conductive connecting piece of the battery pack to be tested in each temperature rising period includes: The shortest period among the temperature rising periods is recorded as the minimum charging period of each conductive connecting piece in the standard battery pack, and the longest period is recorded as the maximum discharging period of each conductive connecting piece in the standard battery pack; Determine a time judgment threshold and a temperature judgment threshold of the standard battery pack according to the difference between the duration and temperature of the minimum charging period and the maximum discharging period of each conductive connecting piece of the standard battery pack; Determine the cumulative time difference and the cumulative temperature difference of each conductive connecting piece of the battery pack to be tested in each heating period according to the time length and the temperature signal difference of each conductive connecting piece of the battery pack to be tested in each heating period; Based on the time accumulation difference and the time judgment threshold, determining the time judgment index of each conductive connecting piece of the battery pack to be tested in each heating period, wherein the time judgment index is negatively correlated with the time accumulation difference and the time judgment threshold respectively; The temperature judgment index of each conductive connecting piece of the battery pack to be tested in each heating period is negatively correlated with the temperature cumulative difference and the temperature judgment threshold value; The battery state judgment factor of each conductive connecting piece of the battery pack to be tested in each temperature rising period is positively correlated with the time judgment index and the temperature judgment index respectively; The step of determining the battery temperature difference index of the battery pack to be tested and judging whether the new energy battery pack has a fault includes: Determine the standard temperature difference of the standard battery pack at each moment in the heating period and the temperature difference to be measured of the battery pack to be tested at each moment in the heating period according to the difference of the temperature signals at each moment between each conductive connecting piece of the standard battery pack and the battery pack to be tested; Determining the relative temperature difference of the battery pack to be tested at each moment in the heating period based on the standard temperature difference and the temperature difference to be tested; The battery temperature difference index of the battery pack to be tested is positively correlated with the relative temperature difference at all times; If the battery temperature difference index is less than or equal to the preset temperature threshold, the battery pack to be tested does not have a fault; otherwise, the battery pack to be tested does have a fault.

2. A signal acquisition method for a new energy battery intelligent management system as claimed in claim 1, characterized in that: The step of determining each temperature rise period of each conductive connecting piece in the standard battery pack and the battery pack to be tested comprises: Constructing a temperature difference sequence of each conductive connecting piece in a standard battery pack at each time period; The sum of all elements in the temperature difference sequence is recorded as the cumulative difference of the temperature change sequence in each period; If the cumulative difference is less than 0, the time period corresponding to the temperature change sequence is recorded as the cooling time period of each conductive connecting piece of the standard battery pack; if the cumulative difference is equal to 0, it is recorded as the dormancy time period of each conductive connecting piece of the standard battery pack; if the cumulative difference is greater than 0, it is recorded as the heating time period of each conductive connecting piece of the standard battery pack; The same acquisition method as that of each conductive connecting piece of a standard battery pack is adopted to obtain each cooling period, each dormant period and each heating period of each conductive connecting piece of the battery pack to be tested.

3. A signal acquisition method for a new energy battery intelligent management system as claimed in claim 2, characterized in that: The method for constructing the temperature difference sequence of each time period of each conductive connecting piece is: The peaks and troughs of the temperature signal at all times for each conductive connecting piece in a standard battery pack; According to the peaks and troughs, the temperature signal of each conductive connecting piece at all times is divided into a plurality of time periods; All temperature signals in each time period are combined into a temperature change sequence of each time period; The first-order difference result of the temperature change sequence is used to obtain the temperature difference sequence of each conductive connecting piece in each time period.

4. A signal acquisition method for a new energy battery intelligent management system as claimed in claim 1, characterized in that: The step of determining a time judgment threshold and a temperature judgment threshold of a standard battery pack includes: The average of the minimum charging time periods of all the conductive connecting pieces of the standard battery pack is recorded as the charging time threshold; The average of the maximum discharge time periods of all the conductive connecting pieces of the standard battery pack is recorded as the discharge time threshold; Determining a time judgment threshold of a standard battery pack according to a difference between the charging time threshold and the discharging time threshold; The temperature judgment threshold of the standard battery pack is obtained by adopting the same method as the time judgment threshold for the temperature signals of the minimum charging period and the maximum discharging period of all the conductive connecting pieces of the standard battery pack.

5. A signal acquisition method for a new energy battery intelligent management system as claimed in claim 4, characterized in that: The step of determining the cumulative time difference and the cumulative temperature difference of each conductive connecting piece of the battery pack to be tested in each heating period includes: Calculate the time length of each conductive connecting piece of the battery pack to be tested in each heating period, and record it as the average time length of each conductive connecting piece to be tested in each heating period; Taking the difference between the average duration to be measured and the charging duration threshold as the first time difference; Taking the difference between the average time length to be measured and the discharge time length threshold as the second time difference; The sum of the first time difference and the second time difference is used as the cumulative time difference of each conductive connecting piece of the battery pack to be tested in each heating period; For the temperature signal of each conductive connecting piece of the battery pack to be tested in each heating period, the same method as the time cumulative difference is adopted to obtain the temperature cumulative difference of each conductive connecting piece of the battery pack to be tested in each heating period.

6. A signal acquisition method for a new energy battery intelligent management system as claimed in claim 1, characterized in that: The step of determining the standard temperature difference of the standard battery pack at each time in the heating period and the temperature difference to be measured of the battery pack to be tested at each time in the heating period includes: Determine the temperature signal difference of each conductive connecting piece at each moment in the heating period according to the difference of the temperature signals of any two conductive connecting pieces of the standard battery pack at the same moment in the heating period; The standard temperature difference of the standard battery pack at each moment in the heating period is positively correlated with the temperature signal difference of all the conductive connecting sheets at each moment in the heating period; For the temperature signal of each conductive connecting piece of the battery pack to be tested at each moment in the heating period, the same method as the standard temperature difference is adopted to obtain the temperature difference to be tested at each moment in the heating period of the battery pack to be tested.

7. A signal acquisition method for a new energy battery intelligent management system as claimed in claim 1, characterized in that: The step of determining the relative temperature difference of the battery pack to be tested at each time point in the temperature rising period includes: The temperature difference thresholds are respectively positively correlated with the standard temperature differences at all moments in the heating period; The difference between the temperature difference to be measured of the battery group to be tested at each moment in the heating period and the temperature difference threshold is determined as the relative temperature difference of the battery group to be tested at each moment in the heating period.

8. A signal acquisition method for a new energy battery intelligent management system as claimed in claim 2, characterized in that: The method for acquiring the fusion temperature signal of the battery pack to be tested at each moment is as follows: For each moment during the temperature rise period of the battery pack to be tested, the maximum temperature signal of all the conductive connecting pieces at the same moment is used as the fusion temperature signal at each moment; For each moment during the cooling period of the battery pack to be tested, the minimum temperature signal of all the conductive connecting pieces at the same moment is used as the fusion temperature signal at each moment; For each moment in the dormant period of the battery pack to be tested, the average temperature signal of all the conductive connecting sheets at the same moment is used as the fusion temperature signal at each moment.

Images