A method, system and device for detecting safety performance of lithium batteries

Abstract

The present invention relates to the technical field of measuring electrical variables, and specifically to a method, system and device for detecting the safety performance of lithium batteries. The method includes: dividing a plurality of time intervals according to the power data of the lithium battery during the charging process; determining the degree of discharge influence of each time interval according to the duration and power fluctuation of each time interval; the discharge influence degree is used to characterize the degree to which the power in the time interval is affected by discharge during the charging process of the lithium battery; determining a target time interval according to the discharge influence degree of each time interval, and merging adjacent target time intervals to obtain a target time period; the discharge influence degree of the target time interval is greater than the discharge influence degree of the non-target time interval; determining the safety performance detection result of the lithium battery according to the safety performance related data in each target time period. This method can improve the accuracy of safety performance detection of lithium batteries.

Description

Technical Field

[0001] The present invention relates to the technical field of measuring electrical variables, and in particular to a method, system and device for detecting the safety performance of lithium batteries. Background Art

[0002] Industrial energy storage equipment is usually used for industrial production needs, and lithium batteries are an important power solution for industrial energy storage equipment. Lithium-ion batteries (lithium batteries) have the advantages of high voltage, high energy density, and low environmental pollution, and are widely used in the field of industrial energy storage. With the rapid development of Internet technology and the sharing economy, as well as the increase in demand for industrial energy storage, users are increasingly relying on industrial energy storage lithium batteries and using them in all-weather scenarios. In order to ensure the safety of lithium batteries and prevent lithium batteries from damaging energy storage equipment during charging, it is very important to test the safety performance of lithium batteries.

[0003] In traditional methods, the safety performance of lithium batteries is generally determined directly based on the temperature data and power data during the charging process. However, in real life, various interferences may occur to the energy storage device during the charging process, which will interfere with the temperature data and power data of the lithium battery, resulting in inaccurate safety performance determined directly based on the temperature data and power data during the charging process. Summary of the invention

[0004] In order to solve the technical problem of inaccurate safety performance detection of lithium batteries, the purpose of the present invention is to provide a method, system and device for safety performance detection of lithium batteries. The technical solution adopted is as follows:

[0005] In a first aspect, the present invention provides a method for detecting safety performance of a lithium battery, comprising:

[0006] According to the power data of the lithium battery during the charging process, multiple time intervals are divided;

[0007] Determine the degree of discharge influence of each time interval according to the duration of each time interval and the fluctuation of power; the degree of discharge influence is used to characterize the degree to which the power is affected by discharge in the time interval during the charging process of the lithium battery;

[0008] Determine a target time interval according to the discharge influence degree of each time interval, and merge adjacent target time intervals to obtain a target time period; the discharge influence degree of the target time interval is greater than the discharge influence degree of the non-target time interval;

[0009] The safety performance test result of the lithium battery is determined based on the safety performance related data within each target time period.

[0010] In a second aspect, the present invention further provides a safety performance detection system for a lithium battery, comprising:

[0011] The interval division module is used to divide the time intervals into multiple time intervals according to the power data of the lithium battery during the charging process;

[0012] A first impact analysis module is used to determine the discharge impact degree of each time interval according to the duration of each time interval and the power fluctuation; the discharge impact degree is used to characterize the degree to which the power is affected by the discharge in the time interval during the lithium battery charging process;

[0013] A second impact analysis module is used to determine a target time interval according to the discharge impact degree of each time interval, and merge adjacent target time intervals to obtain a target time period; the discharge impact degree of the target time interval is greater than the discharge impact degree of the non-target time interval;

[0014] The detection module is used to determine the safety performance detection result of the lithium battery according to the safety performance related data within each target time period.

[0015] In a third aspect, the present invention further provides a safety performance testing device for a lithium battery, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the following steps when executing the computer program:

[0016] According to the power data of the lithium battery during the charging process, multiple time intervals are divided;

[0017] Determine the degree of discharge influence of each time interval according to the duration of each time interval and the fluctuation of power; the degree of discharge influence is used to characterize the degree to which the power is affected by discharge in the time interval during the charging process of the lithium battery;

[0018] Determine a target time interval according to the discharge influence degree of each time interval, and merge adjacent target time intervals to obtain a target time period; the discharge influence degree of the target time interval is greater than the discharge influence degree of the non-target time interval;

[0019] The safety performance test result of the lithium battery is determined based on the safety performance related data within each target time period.

[0020] The present invention has the following beneficial effects:

[0021] According to the power data of the lithium battery during the charging process, multiple time intervals are divided. According to the duration of each time interval and the power fluctuation, the discharge impact of each time interval is determined. According to the discharge impact of each time interval, the target time interval is determined, and the adjacent target time intervals are merged to obtain the target time period, so as to accurately determine the target time period with a relatively large discharge impact. Then, according to the safety performance related data in each target time period, the safety performance test result of the lithium battery is determined, thereby improving the accuracy of the lithium battery safety performance test. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 A schematic diagram of a flow chart of a method for detecting safety performance of a lithium battery provided by an embodiment of the present invention;

[0024] Figure 2 A schematic diagram of a process for determining a safety performance test result of a lithium battery provided by an embodiment of the present invention;

[0025] Figure 3 A schematic diagram of the overall process of a safety performance testing method for a lithium battery provided by an embodiment of the present invention;

[0026] Figure 4 A schematic structural diagram of a safety performance testing device for lithium batteries provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0027] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of a safety performance detection method, system and device for lithium batteries proposed in accordance with the present invention, its specific implementation, structure, features and effects, in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0028] 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 invention belongs.

[0029] The following is a detailed description of a method, system and device for detecting safety performance of lithium batteries provided by the present invention in conjunction with the accompanying drawings.

[0030] See also Figure 1 , which shows a flow chart of a safety performance detection method for a lithium battery provided by an embodiment of the present invention, including the following steps 102 to 108:

[0031] Step 102, dividing a plurality of time intervals according to the power data of the lithium battery during the charging process.

[0032] Among them, power data refers to the real-time power value at each moment.

[0033] In one embodiment, the lithium battery is a battery used in the energy storage device. The energy storage device is a device for storing backup electric energy in industrial scenarios, such as a storage battery in accordance with the IEC62619 standard, or a household energy storage device for household needs.

[0034] In one embodiment, the energy storage device can obtain power data during the charging process of the lithium battery, and then divide the time intervals into multiple time intervals according to the power data.

[0035] In one embodiment, there are multiple common ways to display the power of the energy storage device, including digital percentage, traditional battery icon and personalized battery icon. The present invention can obtain power data in digital percentage form.

[0036] It can be understood that under ideal charging conditions, the charger charges the lithium battery with a stable current and voltage, and the power will increase evenly with the increase of charging time, showing a stable linear growth trend. However, during the charging process of the energy storage device, even if the energy storage device is in a dormant state, the system still runs many monitoring, alarm and protection functions, etc. These processes will occupy system resources from time to time during operation, resulting in power consumption. During the charging process of the energy storage device, when the system starts to perform operations such as automatic data backup and synchronization, the growth rate of power may slow down for a period of time. When the performance of the lithium battery is poor, there may even be a short period of power decrease instead of increase. When the energy storage device is used while charging, especially when performing high-energy-consuming operations, the charging speed will be significantly slower, which is reflected in the longer time it takes for the power to increase. Therefore, the power value of the lithium battery of the energy storage device does not increase continuously during the charging process, but fluctuates up and down.

[0037] In one embodiment, in each divided time interval, the power of the lithium battery increases from the starting power value of the time interval (i.e., the power value at the start of the time interval) to the next power value and does not decrease in the subsequent time interval. That is, the moment when the next power value appears for the last time is taken as the end time of the time interval. The next power value refers to a power value that increases by 1%.

[0038] For example: if the starting power value of a time interval is a, then the last time a+1% of the power value appears is the end time of the time interval. Specifically, starting from the power value 1%, the last time the power value 2% appears in chronological order is the end time of the first time interval, and then the second time interval starts from this moment, and the last time the power value 3% appears is the end time of the second time interval, and so on. For example: assuming that the power data includes {10%, 11%, 10%, 11%, 12%, 11%, 12%, 13%}, then the time period corresponding to {10%, 11%, 10%, 11%, 12%, 11%} can be used as a time interval.

[0039] It is understandable that during the charging process of the lithium battery, if the energy storage device is in use, the power value will not increase linearly, but will fluctuate within a certain range, so the method in the above embodiment is used to divide the time interval according to the power data.

[0040] Step 104, determining the discharge influence degree of each time interval according to the duration of each time interval and the power fluctuation; the discharge influence degree is used to characterize the degree to which the power is affected by discharge in the time interval during the lithium battery charging process.

[0041] In one embodiment, the energy storage device can determine the charging speed stability of each time interval according to the length of each time interval, and then determine the discharge impact degree of each time interval according to the charging speed stability and power fluctuation of each time interval.

[0042] In one embodiment, the power fluctuation condition includes the number of power fluctuations. The number of power fluctuations in a time interval can be determined according to the number of peak values ​​in the power data in the time interval. The peak value refers to the maximum value in the data.

[0043] In one embodiment, the degree of discharge influence is positively correlated with the number of power fluctuations. It can be understood that the more power fluctuations there are, the more it means that the current provided by the charger is insufficient to meet the high energy consumption requirements, and the power of the lithium battery will be consumed to maintain operation, resulting in more frequent power fluctuations and a greater degree of power influence by discharge.

[0044] In one embodiment, the degree of discharge influence is negatively correlated with the stability of charging speed. It can be understood that the worse the charging speed stability is, the more the power of the lithium battery is disturbed by the energy storage device's energy consumption operation, and the more the power of the lithium battery is affected by discharge during charging.

[0045] Step 106, determine the target time interval according to the discharge influence degree of each time interval, and merge adjacent target time intervals to obtain a target time period; the discharge influence degree of the target time interval is greater than the discharge influence degree of the non-target time interval.

[0046] The non-target time interval refers to the time interval other than the target time interval in each time interval.

[0047] In one embodiment, the energy storage device can compare the discharge impact degree of each time interval with a preset impact degree threshold, and if the discharge impact degree is greater than or equal to the preset impact degree threshold, the corresponding time interval is determined as the target time interval. The preset impact degree threshold can be set according to actual conditions, for example, it can be set to 0.7.

[0048] Step 108, determining the safety performance test result of the lithium battery according to the safety performance related data in each target time period.

[0049] Among them, safety performance related data refers to the data required to determine the safety performance test results.

[0050] In one embodiment, the safety performance-related data may include power data, temperature data, and power consumption data of the lithium battery in a target time period during the charging process, as well as the length of the target time period, and at least one of the charging speed stability and discharge impact degree of the lithium battery in each target time interval within the target time period during the charging process.

[0051] In one embodiment, the energy storage device can determine the temperature control capability and power control capability of the lithium battery in each target time period based on the safety performance related data in each target time period, and determine the safety performance test results of the lithium battery based on the temperature control capability and power control capability of the lithium battery in each target time period.

[0052] In one embodiment, the energy storage device can determine the safety performance evaluation coefficient of the lithium battery according to the temperature control capability and power control capability of the lithium battery in each target time period, and determine the safety performance test result of the lithium battery according to the safety performance evaluation coefficient.

[0053] It is understandable that during the charging process of the energy storage device, a series of chemical reactions will occur inside the lithium battery. This process will be accompanied by the generation of heat. If the energy storage device is used for high-energy-consuming operations at the same time, the lithium battery will be in a state of charging and discharging, and the temperature will rise faster. At this time, if during the period when the power is greatly affected by the discharge during the charging process of the lithium battery (i.e. the target time period), the temperature rise rate remains stable and is controlled within a safe range, and the power rises steadily, it means that the lithium battery has good performance, good temperature control ability, and good power control ability.

[0054] In the above-mentioned safety performance testing method for lithium batteries, multiple time intervals are divided according to the power data of the lithium battery during the charging process, and the discharge impact degree of each time interval is determined according to the duration and power fluctuation of each time interval. According to the discharge impact degree of each time interval, the target time interval is determined, and adjacent target time intervals are merged to obtain a target time period, so that the target time period with a relatively large discharge impact can be accurately determined, and then the safety performance test result of the lithium battery is determined according to the safety performance-related data in each target time period, thereby improving the accuracy of the lithium battery safety performance test.

[0055] In one embodiment, the degree of discharge impact of each time interval is determined according to the duration of each time interval and the power fluctuation, including: determining the charging rate of each time interval according to the duration of each time interval; determining the charging speed stability of each time interval according to the duration of each time interval and the charging rate; determining the degree of discharge impact of each time interval according to the charging speed stability, charging rate and power fluctuation of each time interval.

[0056] In one embodiment, the energy storage device may determine the charging rate of the time interval according to the inverse of the duration of the time interval.

[0057] In one embodiment, the energy storage device may determine the discharge impact degree of each time interval according to the charging speed stability, charging rate and number of power fluctuations in the time interval.

[0058] In one embodiment, the degree of discharge influence is negatively correlated with the charging speed stability and the charging rate. It can be understood that the worse the charging speed stability and the slower the charging rate, the more the power of the lithium battery is disturbed by the energy storage device's energy consumption operation, which means that the power of the lithium battery is more affected by discharge during charging.

[0059] In one embodiment, the degree of discharge influence is positively correlated with the number of power fluctuations. It can be understood that the more power fluctuations there are, the more it means that the current provided by the charger is insufficient to meet the high energy consumption requirements, and the power of the lithium battery will be consumed to maintain operation, resulting in more frequent power fluctuations and a greater degree of power influence by discharge.

[0060] It is understandable that under normal circumstances, when the lithium battery is being charged, the current provided by the charger will give priority to powering the pure device system to maintain the operation of the background process, and will also charge the lithium battery. Even if the background process consumes some power, the power output by the charger is sufficient to meet these needs, and the power is less affected by discharge. However, if the lithium battery performs very resource-consuming operations during the charging process, the power consumption and replenishment will be carried out at the same time. When the power consumption is greater than the charging power, the power will decrease instead of increase; if the power of the two is equal, the power may fluctuate within a certain range; only when the charging power is greater than the power used by the lithium battery will the power continue to rise. Therefore, during the charging process of the lithium battery, the lower the charging rate in each time interval and the worse the charging speed stability, the greater the possibility that the lithium battery will perform high-energy-consuming operations in this interval, and the greater the degree of influence of discharge on the power during the charging process of the lithium battery.

[0061] In one embodiment, the energy storage device can determine the natural exponential function value of the inverse of the product of the charging speed stability and the charging rate within the time interval, and then determine the discharge impact degree of the time interval based on the product of the natural exponential function value and the number of power fluctuations.

[0062] In one embodiment, the product of the natural exponential function value and the number of power fluctuations may be normalized to obtain the discharge impact degree of the time interval.

[0063] In one embodiment, the discharge influence degree of the time interval can be determined according to the following formula: {P}_{x}=norm\left [ {\left ( {exp\left ( {-{v}_{x}\times {W}_{x}} \right )} \right )\times {N}_{x}} \right ]

[0064] in, Indicates the degree of discharge influence in the xth time interval. norm() represents a linear normalization function, which is used to normalize data values ​​to between 0 and 1, thereby eliminating the dimension. exp represents an exponential function with a natural constant as the base. Indicates the charging rate in the xth time interval. Indicates the charging level stability in the xth time interval. Indicates the number of power fluctuations in the xth time interval.

[0065] In the above embodiment, the charging rate of each time interval is determined according to the duration of each time interval, and the charging speed stability of each time interval is determined according to the duration and charging rate of each time interval. According to the charging speed stability, charging rate and power fluctuation of each time interval, the discharge impact degree of each time interval can be accurately determined, so that the target time period can be accurately determined according to the discharge impact degree, thereby improving the accuracy of safety performance detection.

[0066] In one embodiment, the charging speed stability of each time interval is determined based on the duration and charging rate of each time interval, including: for each time interval, the charging speed stability of the time interval is determined based on the difference between the charging rate of the time interval and the average of the charging rates of each time interval, and the difference between the duration of the time interval and the average of the duration of each time interval.

[0067] In one embodiment, the charging speed stability of a time interval is positively correlated with a first difference between the charging rate of the time interval and the average of the charging rates of each time interval. The charging speed stability of a time interval is positively correlated with a second difference between the duration of the time interval and the average of the durations of each time interval.

[0068] In one embodiment, the energy storage device can determine, for each time interval, a first difference between the charging rate of the time interval and the average of the charging rates of the time intervals, and a second difference between the duration of the time interval and the average of the duration of the time intervals, and determine the charging speed stability of the time interval based on the product of the first difference and the second difference.

[0069] In one embodiment, the charging speed stability of a time interval may be determined according to the following formula: in, Indicates the charging speed stability in the xth time interval. Indicates the charging rate in the xth time interval. Indicates the average charging rate in each time interval. Indicates the duration of the xth time interval. Represents the mean value of the duration of each time interval.

[0070] In the above embodiment, the greater the difference between the charging rate of each time interval and the average charging rate of each time interval, and the greater the difference between the duration of the time interval and the average duration of each time interval, it means that the power of the lithium battery in the interval is not steadily increasing and will be affected by the use of the lithium battery. Therefore, the charging speed stability of the time interval can be accurately determined based on the difference between the charging rate of the time interval and the average charging rate of each time interval, and the difference between the duration of the time interval and the average duration of each time interval.

[0071] In one embodiment, Figure 2 As shown, step 108 determines the safety performance test result of the lithium battery according to the safety performance related data in each target time period, including the following steps 202 to 208:

[0072] Step 202, determining the temperature control capability of the lithium battery in each target time period according to the safety performance related data in each target time period.

[0073] In one embodiment, the energy storage device can determine the temperature control capability of the lithium battery within each target time period according to the charging speed stability and discharge impact degree of each target time interval within the target time period during the charging process of the lithium battery, as well as the temperature data and power consumption data within the target time period.

[0074] Step 204, determining the power control capability of the lithium battery in each target time period according to the safety performance related data in each target time period.

[0075] In one embodiment, the energy storage device can determine the power control capability of the lithium battery in each target time period according to the power data and power consumption data of the lithium battery in the target time period during the charging process and the length of the target time period.

[0076] Step 206 , determining a safety performance evaluation coefficient of the lithium battery according to the temperature control capability and power control capability of the lithium battery in each target time period.

[0077] In one embodiment, the energy storage device can determine the average temperature control capability of the lithium battery in each target time period and the average power control capability in each target time period, and determine the safety performance evaluation coefficient of the lithium battery based on the average temperature control capability and the average power control capability.

[0078] In one embodiment, the energy storage device can determine the safety performance evaluation coefficient of the lithium battery according to the product of the mean value of the temperature control capability and the mean value of the power control capability. In one embodiment, the product of the mean value of the temperature control capability and the mean value of the power control capability can be normalized to obtain the safety performance evaluation coefficient of the lithium battery.

[0079] Step 208, determining the safety performance test result of the lithium battery according to the safety performance evaluation coefficient.

[0080] In one embodiment, the energy storage device can compare the safety performance evaluation coefficient with the first preset threshold and the second preset threshold. If the safety performance evaluation coefficient is greater than or equal to the first preset threshold, the safety performance test result of the lithium battery is determined to be the first test result; if the safety performance evaluation coefficient is greater than or equal to the second preset threshold and less than the first preset threshold, the safety performance test result of the lithium battery is determined to be the second test result; if the safety performance evaluation coefficient is less than the second preset threshold, the safety performance test result of the lithium battery is determined to be the third test result.

[0081] Among them, the first preset threshold is greater than the second preset threshold. The first preset threshold and the second preset threshold can be set according to actual conditions, for example: the first preset threshold can be set to 0.8, and the second preset threshold can be set to 0.5. The first test result indicates that the performance of the lithium battery is stable, that is, the lithium battery still has good control over temperature and power when it is greatly affected by discharge during the charging process. The second test result indicates that the performance of the lithium battery is average, that is, the lithium battery has poor control over temperature and power when it is greatly affected by discharge during the charging process. Therefore, it should be avoided when charging to avoid further degradation of the performance of the lithium battery. The third test result indicates that the performance of the lithium battery is poor, and the maintenance personnel should be contacted for processing.

[0082] In the above embodiment, the temperature control capability and power control capability of the lithium battery in each target time period are determined based on the safety performance related data in each target time period, and then the safety performance evaluation coefficient of the lithium battery is determined based on the temperature control capability and power control capability of the lithium battery in each target time period. The safety performance test result of the lithium battery is determined based on the safety performance evaluation coefficient, which can accurately determine the safety performance test result of the lithium battery.

[0083] In one embodiment, the safety performance-related data include the charging speed stability and discharge influence degree of the lithium battery in each target time interval within the target time period during the charging process, as well as the temperature data and power consumption data within the target time period; based on the safety performance-related data within each target time period, the temperature control capability of the lithium battery within each target time period is determined, including: for each target time period, based on the charging speed stability of each target time interval within the target time period, and the temperature data within the target time period, determining the temperature rising trend stability within the target time period; based on the discharge influence degree of each target time interval within the target time period, as well as the temperature rising trend stability within the target time period and the fluctuation degree of the power consumption data, determining the temperature control capability of the lithium battery within the target time period.

[0084] In one embodiment, the energy storage device may collect temperature data during the charging process at a preset frequency, which may be once per second or other frequency.

[0085] In one embodiment, the energy storage device can perform curve fitting on the power consumption data within the target time period to obtain a corresponding power consumption fitting curve, and then determine the degree of fluctuation of the power consumption data within the target time period according to the degree of disorder of the tangent slope at each data point on the power consumption fitting curve. In one embodiment, the power consumption data within the target time period can be curve fitted using the least squares method. In one embodiment, the degree of disorder of the tangent slope at each data point can be measured by the entropy of the tangent slope at each data point.

[0086] In one embodiment, the temperature control capability of the lithium battery in the target time period is positively correlated with the stability of the temperature rise trend in the target time period. The temperature control capability of the lithium battery in the target time period is negatively correlated with the fluctuation degree of the power consumption data in the target time period. The temperature control capability of the lithium battery in the target time period is negatively correlated with the mean value of the discharge influence degree of each target time interval in the target time period.

[0087] In one embodiment, the energy storage device can determine the natural exponential function value of the inverse of the product of the fluctuation degree of power consumption data within the target time period and the average value of the discharge impact degree of each target time interval within the target time period, and then determine the temperature control capability of the lithium battery within the target time period based on the product of the natural exponential function value and the stability of the temperature rise trend within the target time period.

[0088] In one embodiment, the temperature control capability of the lithium battery within the target time period can be determined according to the following formula: {C}_{z}={T}_{z}\times exp\left [ {-\left ( {{B}_{z}\times {P}_{z}} \right )} \right ] in, Indicates the temperature control capability of the lithium battery during the zth target time period. Indicates the stability of the temperature rising trend in the zth target time period. exp() represents the natural exponential function. Indicates the fluctuation degree of power consumption data in the zth target time period. It represents the mean value of the discharge influence degree of each target time interval in the zth target time period.

[0089] In the above embodiment, the stability of the temperature rising trend within the target time period is first determined based on the charging speed stability of each target time interval within the target time period and the temperature data within the target time period. Then, the temperature control capability of the lithium battery within the target time period is determined based on the discharge influence degree of each target time interval within the target time period, the temperature rising trend stability within the target time period and the fluctuation degree of the power consumption data. This can accurately determine the temperature control capability of the lithium battery within each target time period.

[0090] In one embodiment, the stability of the temperature rising trend within the target time period is determined based on the charging speed stability of each target time interval within the target time period and the temperature data within the target time period, including: determining the overall charging speed stability within the target time period based on the charging speed stability of each target time interval within the target time period; determining the instability of the temperature rising trend within the target time period based on the discreteness of the temperature data within the target time period and the temperature value span; determining the stability of the temperature rising trend within the target time period based on the overall charging speed stability and the instability of the temperature rising trend within the target time period.

[0091] The temperature value span of the temperature data within the target time period represents the difference between the maximum value and the minimum value of the temperature data within the target time period.

[0092] In one embodiment, the energy storage device may determine the overall charging speed stability within the target time period according to the proportion of the number of charging speed stabilities that do not decrease in chronological order among the charging speed stabilities of each target time interval within the target time period to the total number.

[0093] In one embodiment, the degree of dispersion of the temperature data may be measured by using the variance or standard deviation of the temperature data.

[0094] In one embodiment, the energy storage device may determine the instability of the temperature rising trend within the target time period according to the product of the discreteness of the temperature data within the target time period and the temperature value span.

[0095] In one embodiment, the temperature rising trend stability within the target time period is negatively correlated with the instability of the temperature rising trend within the target time period, and the temperature rising trend stability within the target time period is positively correlated with the overall charging speed stability within the target time period.

[0096] In one embodiment, the energy storage device may determine the stability of the temperature rising trend within the target time period according to the product of the inverse of the instability degree of the temperature rising trend within the target time period and the overall charging speed stability within the target time period.

[0097] In the above embodiment, since the greater the instability of the temperature rising trend, the more irregular the temperature, and the larger the temperature change range, the lower the stability of the temperature rising trend, and the higher the overall charging speed stability, it means that the current and voltage flowing into the lithium battery are relatively stable, and the chemical reaction rate inside the lithium battery is also relatively stable. A stable reaction rate will make the heat increase more stable, and the temperature rising trend stability is higher. Therefore, according to the charging speed stability of each target time interval in the target time period, the overall charging speed stability in the target time period is determined, and according to the discrete degree of temperature data in the target time period and the temperature value span, the instability of the temperature rising trend in the target time period is determined. According to the overall charging speed stability and the instability of the temperature rising trend in the target time period, the temperature rising trend stability in the target time period can be accurately determined.

[0098] In one embodiment, the overall charging speed stability within the target time period is determined according to the charging speed stability of each target time interval within the target time period, including: determining a first-order difference sequence of the charging speed stability of each target time interval within the target time period; determining the overall charging speed stability within the target time period according to the proportion of the number of non-negative numbers in the first-order difference sequence to the total number of data in the first-order difference sequence.

[0099] It can be understood that the number of non-negative numbers in the first-order difference sequence of the charging speed stabilities of each target time interval within the target time period is the number of charging speed stabilities that do not decrease in chronological order among the charging speed stabilities of each target time interval within the target time period.

[0100] In one embodiment, the stability of the temperature rising trend within the target time period can be determined according to the following formula: {T}_{z}=\frac {{W'}_{z}} {{W}_{z}}\times exp\left [ {-{\sigma}_{z}\times \left ( {{T'}_{z,max}-{T'}_{z,min}} \right )} \right ] in, Indicates the stability of the temperature rising trend during the zth target time period. The number of non-negative numbers in the first-order difference sequence representing the stability of the charging speed for each target time interval within the zth target time period. The total number of data in the first-order difference sequence representing the stability of the charging speed in each target time interval within the zth target time period. Indicates the overall charging speed stability during the zth target time period. Represents the variance of the temperature data in the zth target time period. Indicates the maximum value in the temperature data during the zth target time period. Indicates the minimum value in the temperature data during the zth target time period. It indicates the instability of the temperature rising trend in the zth target time period, and exp indicates an exponential function with a natural constant as the base.

[0101] In the above embodiment, the first-order difference sequence of the charging speed stability of each target time interval within the target time period is determined. According to the proportion of the number of non-negative numbers in the first-order difference sequence to the total number of data in the first-order difference sequence, the overall charging speed stability within the target time period can be conveniently and accurately determined.

[0102] In one embodiment, the safety performance-related data include the power data and power consumption data of the lithium battery in the target time period during the charging process and the duration of the target time period; based on the safety performance-related data in each target time period, the power control capability of the lithium battery in each target time period is determined, including: for each target time period, based on the power data in the target time period, determining the power growth rate of the target time period; based on the power consumption data in the target time period, determining the average power consumption at each moment in the target time period; based on the power growth rate in the target time period, the average power consumption and the duration of the target time period, determining the power control capability of the lithium battery in the target time period.

[0103] In one embodiment, the power increase range of the target time period can be determined according to the difference between the power value at the end time and the power value at the start time of the target time period.

[0104] In one embodiment, the power control capability of the lithium battery in the target time period is positively correlated with the power growth rate in the target time period. The power control capability of the lithium battery in the target time period is positively correlated with the average power consumption at each moment in the target time period. The power control capability of the lithium battery in the target time period is negatively correlated with the duration of the target time period.

[0105] It can be understood that the energy storage device will dynamically adjust the charging power according to the usage during the charging process. When the energy storage device is used while charging, the power consumption in different usage scenarios will also be different. For example: special periods of large-scale discharge demand, or different time periods for different discharge demands. If the lithium battery can maintain the increase in power in each charging and discharging stage, it means that the lithium battery can quickly and accurately adjust the charging power according to different usage scenarios, that is, the better the ability to control power. Therefore, the power control ability of the lithium battery in the target time period is positively correlated with the power growth rate and the average power consumption in the target time period. In addition, the less time required for power growth (that is, the shorter the duration of the target time period), the better the lithium battery's power retention ability, that is, the better the lithium battery's power control ability. Therefore, the power control ability of the lithium battery in the target time period is negatively correlated with the duration of the target time period.

[0106] In one embodiment, the energy storage device can determine the power control capability of the lithium battery within the target time period based on the product of the inverse of the target time period, the power growth rate within the target time period, and the average power consumption at each moment within the target time period.

[0107] In one embodiment, the power control capability of the lithium battery within the target time period can be determined according to the following formula: in, Indicates the power control capability of the lithium battery during the zth target time period. Indicates the duration of the target time period. Indicates the power value at the end of the zth target time period. Indicates the power value at the start time of the zth target time period. Indicates the increase in power consumption during the zth target time period. Represents the average power consumption at each moment in the zth target time period.

[0108] In the above embodiments, for each target time period, the power growth rate of the target time period is determined based on the power data within the target time period, and the average power consumption at each moment within the target time period is determined based on the power consumption data within the target time period. Based on the power growth rate within the target time period, the average power consumption and the duration of the target time period, the power control capability of the lithium battery within the target time period can be accurately determined.

[0109] like Figure 3As shown, it is a schematic diagram of the overall process of the safety performance detection method for lithium batteries provided by the present invention. First, the energy storage device obtains the power data, temperature data and power consumption data at each moment in the charging process, and then divides the time interval according to the power data to determine the charging rate of the time interval, and determines the charging speed stability of each time interval according to the duration and charging rate of each time interval. Then, the degree of discharge influence is determined according to the charging speed stability, and several time periods with large discharge influence are screened out (i.e., target time periods). According to the temperature data of each time period with large discharge influence, the temperature control ability of the lithium battery in each time period with large discharge influence is determined, and then according to the amplitude of power growth and power consumption in each time period with large discharge influence, the power control ability of the lithium battery in each time period with large discharge influence is determined. Finally, according to the temperature control ability and power control ability of the lithium battery, the safety performance detection result of the lithium battery is determined.

[0110] It should be understood that, although the steps in the flowcharts involved in the above embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps is not strictly limited in order, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above embodiments may include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0111] Based on the same inventive concept, the embodiment of the present application also provides a safety performance detection system for lithium batteries for implementing the above-mentioned safety performance detection method for lithium batteries. The system includes:

[0112] The interval division module is used to divide the time intervals into multiple time intervals according to the power data of the lithium battery during the charging process;

[0113] A first impact analysis module is used to determine the discharge impact degree of each time interval according to the duration of each time interval and the power fluctuation; the discharge impact degree is used to characterize the degree to which the power is affected by the discharge in the time interval during the lithium battery charging process;

[0114] A second impact analysis module is used to determine a target time interval according to the discharge impact degree of each time interval, and merge adjacent target time intervals to obtain a target time period; the discharge impact degree of the target time interval is greater than the discharge impact degree of the non-target time interval;

[0115] The detection module is used to determine the safety performance detection result of the lithium battery according to the safety performance related data within each target time period.

[0116] The implementation solution provided by the system to solve the problem is similar to the implementation solution recorded in the above method. Therefore, the specific limitations in the embodiment of the safety performance testing system for lithium batteries provided below can be found in the above limitations on the safety performance testing method for lithium batteries, and will not be repeated here.

[0117] In one embodiment, an embodiment of the present invention provides a safety performance testing device for lithium batteries. The device includes a memory and a processor. The memory stores a computer program. When the processor executes the computer program, a safety performance testing method for lithium batteries is implemented.

[0118] In one embodiment, the internal structure diagram of the safety performance testing device for lithium batteries can be as follows: Figure 4 As shown. The device includes a processor, a memory, an input / output interface, a communication interface, a display unit and an input device. The processor, the memory and the input / output interface are connected through a system bus, and the communication interface, the display unit and the input device are connected to the system bus through the input / output interface. The processor of the device is used to provide computing and control capabilities. The memory of the device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the device is used to exchange information between the processor and an external device. The communication interface of the device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be realized through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a method for detecting the safety performance of a lithium battery is realized. The display unit of the device is used to form a visually visible picture, which can be a display screen, a projection device or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device of the device can be a touch layer covering the display screen, or a button, trackball or touchpad set on the device casing, or an external keyboard, touchpad or mouse.

[0119] Those skilled in the art will understand that Figure 4 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific device may include more or fewer components than shown in the figure, or combine certain components, or have a different arrangement of components.

[0120] It should be noted that the sequence of the above embodiments of the present invention is for description only and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0121] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0122] It should be noted that the data involved in this application (including but not limited to data used for analysis, stored data, displayed data, etc.) are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of relevant data must comply with relevant regulations.

[0123] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The processor involved in each embodiment provided in this application can be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic unit, a data processing logic unit based on quantum computing, etc., but is not limited thereto.

[0124] 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.

[0125] The above 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 scope of the present application. It should be pointed out that, for those of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application.

Claims

1. A method for detecting the safety performance of a lithium battery, characterized in that: The method comprises: According to the power data of the lithium battery during the charging process, multiple time intervals are divided, wherein in each divided time interval, the power of the lithium battery increases from the starting power value of the time interval to the next power value and does not decrease in the subsequent time intervals, and the next power value refers to the power value increasing by 1%; Determine the degree of discharge influence of each time interval according to the duration of each time interval and the fluctuation of power; the degree of discharge influence is used to characterize the degree to which the power is affected by discharge in the time interval during the charging process of the lithium battery; Determine a target time interval according to the discharge influence degree of each time interval, and merge adjacent target time intervals to obtain a target time period; the discharge influence degree of the target time interval is greater than the discharge influence degree of the non-target time interval; The safety performance test result of the lithium battery is determined based on the safety performance related data within each target time period.

2. A safety performance testing method for lithium batteries according to claim 1, characterized in that: Determining the discharge impact degree of each time interval according to the duration of each time interval and the power fluctuation includes: Determining a charging rate for each of the time intervals according to the length of each of the time intervals; Determining the charging speed stability of each of the time intervals according to the duration of each of the time intervals and the charging rate; The degree of discharge influence in each of the time intervals is determined according to the charging speed stability, the charging rate and the power fluctuation in each of the time intervals.

3. A safety performance testing method for lithium batteries according to claim 2, characterized in that: Determining the charging speed stability of each time interval according to the duration of each time interval and the charging rate includes: For each of the time intervals, the charging speed stability of the time interval is determined based on the difference between the charging rate of the time interval and the average of the charging rates of the time intervals, and the difference between the duration of the time interval and the average of the duration of the time intervals.

4. A safety performance testing method for lithium batteries according to claim 1, characterized in that: Determining the safety performance test result of the lithium battery according to the safety performance related data within each target time period includes: Determining the temperature control capability of the lithium battery within each of the target time periods according to the safety performance related data within each of the target time periods; Determining the power control capability of the lithium battery within each of the target time periods according to the safety performance related data within each of the target time periods; Determining a safety performance evaluation coefficient of the lithium battery according to the temperature control capability and power control capability of the lithium battery in each of the target time periods; The safety performance test result of the lithium battery is determined according to the safety performance evaluation coefficient.

5. A safety performance testing method for lithium batteries according to claim 4, characterized in that: The safety performance related data includes the charging speed stability and discharge impact degree of the lithium battery in each target time interval within the target time period during the charging process, as well as the temperature data and power consumption data within the target time period; Determining the temperature control capability of the lithium battery within each target time period according to the safety performance related data within each target time period includes: For each of the target time periods, respectively, according to the charging speed stability of each target time interval in the target time period and the temperature data in the target time period, determine the temperature rising trend stability in the target time period; The temperature control capability of the lithium battery within the target time period is determined according to the discharge influence degree of each target time interval within the target time period, the temperature rising trend stability within the target time period, and the fluctuation degree of the power consumption data.

6. A safety performance testing method for lithium batteries according to claim 5, characterized in that: The determining the stability of the temperature rising trend within the target time period according to the charging speed stability of each target time interval within the target time period and the temperature data within the target time period includes: Determining the overall charging speed stability within the target time period according to the charging speed stability of each target time interval within the target time period; Determining the instability of the temperature rising trend within the target time period according to the discreteness of the temperature data within the target time period and the temperature value span; The temperature rising trend stability within the target time period is determined according to the overall charging speed stability within the target time period and the instability of the temperature rising trend.

7. A safety performance testing method for lithium batteries according to claim 6, characterized in that: The determining the overall charging speed stability within the target time period according to the charging speed stability of each target time interval within the target time period includes: Determine a first-order difference sequence of charging speed stability for each target time interval within the target time period; The overall charging speed stability within the target time period is determined according to the proportion of the number of non-negative numbers in the first-order difference sequence to the total number of data in the first-order difference sequence.

8. A safety performance testing method for lithium batteries according to claim 4, characterized in that: The safety performance related data includes power data and power consumption data of the lithium battery in a target time period during charging and the duration of the target time period; Determining the power control capability of the lithium battery within each target time period according to the safety performance related data within each target time period includes: For each target time period, determine the increase range of the power in the target time period according to the power data in the target time period; Determine the average power consumption at each moment in the target time period according to the power consumption data in the target time period; The power control capability of the lithium battery within the target time period is determined according to the power growth rate within the target time period, the average power consumption and the duration of the target time period.

9. A safety performance testing system for lithium batteries, characterized in that: The system comprises: The interval division module is used to divide the power data of the lithium battery during the charging process into multiple time intervals, wherein, in each divided time interval, the power of the lithium battery increases from the starting power value of the time interval to the next power value and does not decrease in the subsequent time intervals, and the next power value refers to the power value increasing by 1%; A first impact analysis module is used to determine the discharge impact degree of each time interval according to the duration of each time interval and the power fluctuation; the discharge impact degree is used to characterize the degree to which the power is affected by the discharge in the time interval during the lithium battery charging process; A second impact analysis module is used to determine a target time interval according to the discharge impact degree of each time interval, and merge adjacent target time intervals to obtain a target time period; the discharge impact degree of the target time interval is greater than the discharge impact degree of the non-target time interval; The detection module is used to determine the safety performance detection result of the lithium battery according to the safety performance related data within each target time period.

10. A safety performance testing device for lithium batteries, characterized in that: The device comprises a memory and a processor, wherein the memory stores a computer program, and the processor implements the safety performance detection method for a lithium battery according to any one of claims 1 to 8 when executing the computer program.

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