Cylindrical battery comprehensive performance rapid detection system and detection method

Abstract

This invention discloses a rapid testing system and method for the comprehensive performance of cylindrical batteries, belonging to the field of battery comprehensive performance testing technology. The system includes: a micro-current pulse excitation module for pulse-exciting the battery and constructing a transient temperature field on the battery surface; an infrared imaging module for acquiring thermal data of the battery based on the transient temperature field; an electrical signal acquisition module for acquiring electrical data of the battery; a thermoelectric coupling module for acquiring thermoelectric coupling parameters based on the electrical data and the battery's thermal data; these thermoelectric coupling parameters include DC internal resistance, AC impedance, thermal conductivity, and the temperature coefficient of DC internal resistance; and a risk labeling module for determining the risk type based on the comparison results of the thermoelectric coupling parameters and preset thresholds. This invention enables rapid and accurate testing of the comprehensive performance of batteries through the simultaneous detection of electrical and thermal data.

Description

Technical Field

[0001] This application relates to the field of battery comprehensive performance testing technology, specifically a rapid testing system and method for the comprehensive performance of cylindrical batteries. Background Technology

[0002] In actual charge and discharge conditions, the thermal and electrical performance of a battery are highly coupled. Temperature changes directly alter the battery's internal resistance and capacity output efficiency, while internal resistance losses also generate heat, affecting its thermal stability. Traditional battery performance testing methods typically test electrical indicators such as internal resistance and impedance separately from thermal indicators such as thermal conductivity and thermal stability. This approach has the following drawbacks:

[0003] The performance test results deviate significantly from the actual performance of the battery; moreover, the traditional thermal performance testing process requires a long heating and cooling pretreatment step, making the overall testing time-consuming. Summary of the Invention

[0004] In view of the deficiencies in the existing technology, the technical problem to be solved by this application is: how to achieve rapid and accurate detection of the overall performance of batteries.

[0005] To achieve the above objectives, in a first aspect, embodiments of this application provide a rapid testing system for the comprehensive performance of cylindrical batteries, the system comprising:

[0006] Microcurrent pulse excitation module: It is used to pulse excite the battery and build a transient temperature field on the battery surface;

[0007] Infrared imaging module: It is used to acquire battery thermal data based on transient temperature fields;

[0008] Electrical signal acquisition module: It is used to acquire the electrical data of the battery;

[0009] Thermoelectric coupling module: It is used to obtain thermoelectric coupling parameters based on electrical data and battery thermal data; these thermoelectric coupling parameters include DC internal resistance, AC impedance, thermal conductivity and DC internal resistance temperature coefficient;

[0010] Risk labeling module: It is used to determine the risk type based on the comparison results of thermoelectric coupling parameters and preset thresholds.

[0011] In conjunction with the first aspect, in one embodiment, the microcurrent pulse excitation module includes a DC pulse unit and a disturbance pulse unit;

[0012] The DC pulse unit excites the battery using a single-pulse, single-excitation mode, with a pulse current amplitude of 40mA-60mA, a frequency of 0.1kHz-1kHz, a bandwidth of 0.01kHz-1kHz, and a pulse width of 8ms-12ms.

[0013] The disturbance pulse unit excites the battery using a single-pulse, single-excitation mode, works synchronously with the DC pulse unit, and has a pulse current amplitude of 1mA-2mA, a frequency of 100kHz-1MHz, a bandwidth of 10kHz-50kHz, and a pulse width of 1us-2us.

[0014] In conjunction with the first aspect, in one embodiment, the infrared imaging module includes an infrared scanning unit and a feature extraction unit. The infrared scanning unit is used to scan and capture the transient temperature of the battery surface.

[0015] The feature extraction unit is used to determine the average temperature, maximum temperature, and temperature gradient of the battery surface based on the transient temperature of all points within the same sampling period, as battery thermal data.

[0016] In conjunction with the first aspect, in one embodiment, the electrical data includes the current and voltage at both ends of the battery;

[0017] The electrical data collected during the operation of the DC pulse unit is defined as DC electrical data;

[0018] The electrical data collected by the disturbance pulse unit during operation is defined as AC electrical data.

[0019] In conjunction with the first aspect, in one embodiment, the thermoelectric coupling module includes a data diagnostic unit, a DC internal resistance calculation unit, an AC impedance calculation unit, and an inversion and deduction unit;

[0020] The data diagnostic unit is used to determine whether the battery thermal data is normal.

[0021] The DC internal resistance calculation unit is used to obtain the DC internal resistance of the battery based on the DC electrical data when the battery thermal data is normal.

[0022] The AC impedance calculation unit is used to analyze AC electrical data through fast Fourier transform to obtain the AC impedance of the battery.

[0023] The inversion calculation unit is used to determine the thermal conductivity and DC internal resistance temperature coefficient of the battery based on the battery size, DC internal resistance, AC impedance and battery thermal data.

[0024] In conjunction with the first aspect, in one embodiment, the process for determining whether the battery thermal data is normal includes:

[0025] The pulse excitation is determined based on the actual output current value and pulse width of the DC pulse unit. If the pulse excitation exceeds the preset pulse threshold, it is determined that the current pulse excitation is inaccurate and the pulse excitation is repeated; otherwise, the pulse excitation is determined to be normal.

[0026] After confirming that the pulse excitation is normal, it is determined whether the battery thermal data exceeds the preset temperature field threshold. If so, the battery thermal data is determined to be abnormal, that is, there is a transient temperature field unevenness; otherwise, the battery thermal data is determined to be normal.

[0027] When the battery thermal data is determined to be abnormal, the battery is repeatedly pulse-excited using a DC pulse unit, and it is determined in turn whether the corresponding pulse excitation exceeds the preset threshold and whether the battery thermal data is normal. If the determination result of the battery thermal data is still abnormal, the battery is marked as a suspected damaged battery.

[0028] In conjunction with the first aspect, in one embodiment, the process of obtaining the DC internal resistance of the battery based on DC electrical data includes:

[0029] The voltage and current at both ends of the battery are selected during the pulse stabilization period. The ratio of the absolute voltage fluctuation difference to the absolute current fluctuation difference at both ends of the battery is used as the ideal DC internal resistance of the battery.

[0030] The corrected DC internal resistance is obtained based on the battery's ideal DC internal resistance and the average temperature during the pulse stabilization period. The calculation formula is as follows:

[0031] ;

[0032] In the formula, This is the corrected DC internal resistance. This is the temperature reference coefficient for the DC internal resistance of the battery. The average temperature. This is the standard reference temperature.

[0033] In conjunction with the first aspect, in one embodiment, the process for obtaining the thermal conductivity includes:

[0034] Construct a heat conduction model, which includes:

[0035] ;

[0036] In the formula, For temperature gradient, Thermal conductivity, The heat flux density is calculated as follows:

[0037] ;

[0038] In the formula, This represents the actual output current of the DC pulse unit. This represents the cross-sectional area of ​​the battery.

[0039] The heat conduction model is iterated using the least squares method to obtain the predicted temperature gradient, and the gradient with the smallest error compared to the above temperature gradient is selected. The value is used as the thermal conductivity of the battery;

[0040] The process for obtaining the DC internal resistance temperature coefficient includes:

[0041] A temperature resistance characteristic model is constructed, which includes:

[0042] ;

[0043] In the formula, The DC internal resistance of the battery at 25°C. The temperature coefficient of DC internal resistance;

[0044] Substituting the continuous ideal DC internal resistance and average temperature of the battery into the temperature resistance characteristic model, and performing linear regression fitting using the least squares method, the final value is determined based on the slope and intercept. The value is used as the temperature coefficient of the battery's DC internal resistance.

[0045] The DC internal resistance calculation unit obtains the final DC internal resistance based on the battery's DC internal resistance temperature coefficient.

[0046] In conjunction with the first aspect, in one embodiment, the process for determining the risk type includes:

[0047] Based on the actual output current of the DC pulse unit, the cross-sectional area and thermal conductivity of the battery, determine the maximum temperature gradient under the current operating conditions, and judge whether the temperature gradient is greater than the maximum temperature gradient. If so, it is determined that the battery has abnormal heat dissipation and indicates that the high temperature heat dissipation pressure is high; otherwise, it is determined that the battery heat dissipation is normal.

[0048] Calculate the absolute deviation between the DC internal resistance temperature coefficient and the battery DC internal resistance temperature reference coefficient, and determine whether the absolute deviation exceeds the preset temperature coefficient threshold. If so, determine that the battery has abnormal internal resistance decay; otherwise, determine that the internal resistance decay is normal.

[0049] Secondly, embodiments of this application provide a method for rapid testing of the overall performance of a cylindrical battery, the method comprising the following steps:

[0050] S1. The DC pulse unit applies pulse excitation to the battery to construct a transient temperature field on the battery surface and obtains the battery thermal data based on the transient temperature field.

[0051] S2. Collect the current and voltage at both ends of the battery as DC electrical data;

[0052] S3. Obtain the corrected DC internal resistance of the battery based on the DC electrical data;

[0053] S4. The disturbance pulse unit applies pulse excitation to the battery and collects the current and voltage at both ends of the battery as AC electrical data.

[0054] S5. Analyze the AC electrical data using Fast Fourier Transform to obtain the AC impedance of the battery;

[0055] S6. Determine the thermal conductivity and temperature coefficient of DC internal resistance of the battery based on the battery size, the corrected DC internal resistance, AC impedance and battery thermal data.

[0056] S7. Obtain the final DC internal resistance based on the temperature coefficient of the battery's DC internal resistance.

[0057] S8. Based on the actual output current of the DC pulse unit, the cross-sectional area and thermal conductivity of the battery, determine the maximum temperature gradient under the current operating conditions. If the temperature gradient is greater than the maximum temperature gradient, it is determined that the battery has an abnormal heat dissipation.

[0058] Calculate the absolute deviation between the DC internal resistance temperature coefficient and the battery DC internal resistance temperature reference coefficient. If the absolute deviation exceeds the preset temperature coefficient threshold, it is determined that the battery has an abnormal internal resistance decay.

[0059] Compared with the prior art, the advantages of this application are:

[0060] The transient temperature field of the battery surface can be rapidly obtained by pulse excitation without the need for long-term heating and cooling. Combined with high-frequency perturbation pulses, thermoelectric coupling parameters can be obtained. In this way, the rapid and accurate detection of the battery's comprehensive performance can be achieved through the simultaneous detection of electrical and thermal data. Attached Figure Description

[0061] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0062] Figure 1 This is a schematic diagram of the method flow of the second aspect in the embodiments of this application. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0064] The flowchart shown in the attached diagram is for illustrative purposes only and does not necessarily include all content and operations / steps, nor does it necessarily have to be performed in the order described. For example, some operations / steps can be broken down, combined, or partially merged, so the actual execution order may change depending on the actual situation.

[0065] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0066] In a first aspect, embodiments of this application provide a rapid testing system for the comprehensive performance of a cylindrical battery, the system comprising:

[0067] Microcurrent pulse excitation module: It is used to pulse excite the battery and build a transient temperature field on the battery surface;

[0068] Infrared imaging module: It is used to acquire battery thermal data (average temperature, maximum temperature, and temperature gradient of the battery surface) based on the transient temperature field.

[0069] Electrical signal acquisition module: It is used to acquire the battery's electrical data (voltage, current);

[0070] Thermoelectric coupling module: It is used to obtain thermoelectric coupling parameters (DC internal resistance, AC impedance, thermal conductivity, DC internal resistance temperature coefficient) based on electrical data and battery thermal data.

[0071] Risk labeling module: It is used to determine the risk type based on the comparison results of thermoelectric coupling parameters and preset thresholds.

[0072] The aforementioned microcurrent pulse excitation module, infrared imaging module, and electrical signal acquisition module share the same nanosecond-level clock source, completely avoiding timing misalignment. This allows for the rapid acquisition of the transient temperature field on the battery surface through pulse excitation, eliminating the need for prolonged heating and cooling. Combined with high-frequency perturbation pulses, thermoelectric coupling parameters can be obtained. Thus, through the simultaneous detection of electrical and thermal data, rapid and accurate detection of the battery's overall performance can be achieved.

[0073] In one embodiment, the micro-current pulse excitation module includes a DC pulse unit and a disturbance pulse unit, and only one unit of the DC pulse unit and the disturbance pulse unit operates at a time. The DC pulse unit excites the battery using a single-pulse, single-use excitation mode, with a pulse current amplitude of 40mA-60mA, a frequency of 0.1kHz-1kHz, a bandwidth of 0.01kHz-1kHz, and a pulse width of 8ms-12ms.

[0074] The perturbation pulse unit excites the battery using a single-pulse, single-excitation mode, operating synchronously with the DC pulse unit. The pulse current amplitude is 1mA-2mA, the frequency is 100kHz-1MHz, the bandwidth is 10kHz-50kHz, and the pulse width is 1µs-2µs. The emitted perturbation pulse amplitude is extremely small, generating negligible Joule heat. It does not alter the established transient temperature field or damage the battery, ensuring non-destructive testing. Furthermore, it is applied step-by-step with the DC main pulse without superposition, avoiding signal interference and ensuring a pure AC signal.

[0075] For the construction of transient temperature fields, in use, the two flexible gold-plated probes of the DC pulse unit are respectively connected to the positive and negative terminals of the cylindrical battery under test, and after ensuring that the contact is secure, the DC pulse unit outputs a stable and controllable micro-current according to the preset fixed excitation parameters. The current flows through the internal AC impedance of the cylindrical lithium battery, generating a uniform micro Joule heat. The Joule heat is quickly conducted to the battery surface, constructing a stable transient temperature field on the battery surface.

[0076] This method avoids damage to the battery by pre-setting pulse parameters (achieving non-destructive testing) and quickly builds a stable transient temperature field, eliminating the need for long-term temperature control preprocessing in traditional testing.

[0077] In one embodiment, the infrared imaging module synchronously acquires battery thermal data while the DC pulse unit is operating. Specifically, the infrared imaging module includes an infrared scanning unit and a feature extraction unit. The infrared scanning unit is used to scan and capture (sampling frequency of 10Hz, temperature measurement accuracy of ±0.1℃) the transient temperature of all points on the battery surface.

[0078] The feature extraction unit is used to determine the average temperature, maximum temperature, and temperature gradient of the battery surface based on the transient temperatures of all points within the same sampling period. This is achieved by calculating the instantaneous temperature difference between adjacent points, dividing the difference by the actual distance between the points to obtain the rate of temperature change per unit distance, which is the temperature gradient and reflects the uniformity of the transient temperature field. This is then stored in time as the battery's thermal data, forming a temperature numerical sequence. This temperature numerical sequence comprehensively records the dynamic changes of the transient temperature field from its initial construction to its eventual stabilization, mitigating the random errors inherent in single-point instantaneous data.

[0079] In one embodiment, the electrical signal acquisition module synchronously acquires the electrical data of the battery when the DC pulse unit or the disturbance pulse unit is working. The electrical data includes the current and voltage at both ends of the battery.

[0080] The electrical data collected when the DC pulse unit is working is used as DC electrical data, where the current is the actual output current of the DC pulse unit;

[0081] The electrical data collected when the disturbance pulse unit is working is used as AC electrical data.

[0082] In one embodiment, the thermoelectric coupling module includes a data diagnostic unit, a DC internal resistance calculation unit, an AC impedance calculation unit, and an inversion calculation unit.

[0083] The data diagnostic unit is used to determine whether the battery thermal data is normal. The process for determining whether the battery thermal data is normal includes:

[0084] Based on the actual output current value and pulse width of the DC pulse unit, determine whether the pulse excitation exceeds the preset pulse threshold (pulse current amplitude: 40mA-60mA, pulse width: 8ms-12ms). If so, determine that the current pulse excitation is inaccurate and re-perform pulse excitation; otherwise, determine that the pulse excitation is normal.

[0085] After confirming that the pulse excitation is normal, determine whether the battery thermal data exceeds the preset temperature field threshold (e.g., battery temperature rise ≥ 3℃ and temperature gradient ≥ 0.5℃ / mm). If so, determine that the battery thermal data is abnormal, that is, there is a transient temperature field temperature unevenness; otherwise, determine that the battery thermal data is normal.

[0086] When abnormal battery thermal data is detected, a DC pulse unit is used to repeatedly pulse-excite the battery, and it is then checked whether the corresponding pulse excitation exceeds a preset threshold and whether the battery thermal data is normal. If the battery thermal data is still abnormal, the battery is marked as a suspected damaged battery and requires manual repair. This ensures the authenticity and validity of the battery thermal data.

[0087] The DC internal resistance calculation unit is used to obtain the ideal DC internal resistance of the battery based on DC electrical data when the battery's hot-state data is normal. Specifically: it extracts continuous (time-series distributed) DC electrical data during the excitation period of the DC pulse unit, filters the voltage and current at both ends of the battery during the pulse stabilization period (when the voltage drop slope is linear and constant, such as the absolute value of the voltage change rate ≤ 0.1mV / μs for 5 consecutive sampling points), and obtains the ideal DC internal resistance of the battery based on the absolute voltage fluctuation difference and the absolute current fluctuation difference; the formula for calculating the ideal DC internal resistance of the battery is:

[0088] ;

[0089] In the formula, The ideal DC internal resistance of the battery (unit: mΩ). This represents the absolute voltage fluctuation difference across the battery terminals (unit: mV). This represents the absolute current fluctuation difference across the battery terminals during the corresponding time period (unit: mA).

[0090] The average temperature during the pulse stabilization period is used to perform temperature compensation correction on the ideal DC internal resistance, obtaining the corrected DC internal resistance; the calculation formula for temperature compensation correction is as follows:

[0091] ;

[0092] In the formula, This is the corrected DC internal resistance (unit: mΩ). This is the temperature reference coefficient for the DC internal resistance of the battery (e.g., 0.002 / ℃ for lithium batteries). Average temperature (unit: °C). This is the standard reference temperature (e.g., 25℃).

[0093] The AC impedance calculation unit is used to analyze AC electrical data through Fast Fourier Transform to obtain the AC impedance of the battery. The formula for calculating the AC impedance is:

[0094] ;

[0095] In the formula, For AC impedance, The real part of the AC impedance (representing the ohmic loss and electrochemical polarization loss of the battery, in mΩ). It is the imaginary unit (used to distinguish between the real and imaginary parts of AC impedance). This represents the imaginary part of the AC impedance (representing the capacitive and inductive reactance characteristics of the battery, in mΩ).

[0096] The inversion calculation unit is used to determine the thermal conductivity and DC internal resistance temperature coefficient of the battery based on the battery size (diameter, length), DC internal resistance (corrected DC internal resistance), AC impedance and battery thermal data.

[0097] The process for obtaining thermal conductivity includes:

[0098] Construct a heat conduction model, which includes:

[0099] ;

[0100] In the formula, For temperature gradient, Thermal conductivity, The heat flux density is calculated as follows:

[0101] ;

[0102] In the formula, This represents the actual output current of the DC pulse unit. This represents the cross-sectional area of ​​the battery.

[0103] The heat conduction model is iterated using the least squares method to obtain the predicted temperature gradient, and the gradient with the smallest error compared to the above temperature gradient is selected. The value is used as the thermal conductivity of the battery.

[0104] The process for obtaining the DC internal resistance temperature coefficient includes:

[0105] A temperature resistance characteristic model is constructed, which includes:

[0106] ;

[0107] In the formula, The DC internal resistance of the battery at 25°C. The temperature coefficient of DC internal resistance;

[0108] Substituting the continuous ideal DC internal resistance and average temperature of the battery into the temperature resistance characteristic model, and performing linear regression fitting using the least squares method, the final value is determined based on the slope and intercept. The value is used as the temperature coefficient of the battery's DC internal resistance.

[0109] Based on this, the DC internal resistance calculation unit calls the temperature compensation correction formula to obtain the final DC internal resistance according to the DC internal resistance temperature coefficient of the battery (simply replace the DC internal resistance temperature reference coefficient with the DC internal resistance temperature coefficient).

[0110] Furthermore, the risk labeling module determines the risk type based on the comparison results between thermoelectric coupling parameters and preset thresholds. The process for determining the risk type includes:

[0111] Based on the actual output current of the DC pulse unit, the cross-sectional area of ​​the battery, and its thermal conductivity, determine the maximum temperature gradient under the current operating conditions (e.g., taking the maximum value of the pulse current amplitude, 60mA, for calculation). The formula for calculating this maximum temperature gradient is:

[0112]

[0113] In the formula, For the maximum temperature gradient, The length of the battery;

[0114] Determine if the above temperature gradient is greater than the maximum temperature gradient. If so, determine that the battery has an abnormal heat dissipation and indicate that the high temperature heat dissipation pressure is high; otherwise, determine that the battery heat dissipation is normal.

[0115] Calculate the absolute deviation between the DC internal resistance temperature coefficient and the battery DC internal resistance temperature reference coefficient, and determine whether the absolute deviation exceeds the preset temperature coefficient threshold (e.g., 0.0005). If so, it is determined that the battery has abnormal internal resistance decay (i.e., there are electrochemical degradation problems such as SEI film thickening and electrolyte aging); otherwise, it is determined that the internal resistance decay is normal.

[0116] Secondly, referring to Figure 1 This application provides a method for rapid testing of the overall performance of a cylindrical battery, the method comprising the following steps:

[0117] S1. The DC pulse unit applies pulse excitation to the battery to construct a transient temperature field on the battery surface and obtains the battery thermal data (average temperature, maximum temperature, and temperature gradient of the battery surface) based on the transient temperature field.

[0118] S2. Collect the current and voltage at both ends of the battery as DC electrical data;

[0119] S3. Obtain the corrected DC internal resistance of the battery based on the DC electrical data (see the calculation formula for temperature compensation correction above).

[0120] S4. The disturbance pulse unit applies pulse excitation to the battery and collects the current and voltage at both ends of the battery as AC electrical data.

[0121] S5. Analyze the AC electrical data using Fast Fourier Transform to obtain the AC impedance of the battery (see the calculation formula for AC impedance above).

[0122] S6. Based on the battery size, corrected DC internal resistance, AC impedance and battery thermal data, determine the battery's thermal conductivity (see the above process for obtaining thermal conductivity) and DC internal resistance temperature coefficient (see the above process for obtaining DC internal resistance temperature coefficient).

[0123] S7. Obtain the final DC internal resistance based on the temperature coefficient of the battery's DC internal resistance.

[0124] S8. Based on the actual output current of the DC pulse unit, the cross-sectional area and thermal conductivity of the battery, determine the maximum temperature gradient under the current operating conditions (see the calculation formula for the maximum temperature gradient above). If the temperature gradient is greater than the maximum temperature gradient, it is determined that the battery has an abnormal heat dissipation.

[0125] Calculate the absolute deviation between the DC internal resistance temperature coefficient and the battery DC internal resistance temperature reference coefficient. If the absolute deviation exceeds the preset temperature coefficient threshold, it is determined that the battery has an abnormal internal resistance decay.

[0126] It should be noted that the sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0127] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0128] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0129] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0130] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0131] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of this application.

[0132] The above are merely specific embodiments of this application, but the protection scope of this application is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this application, and these modifications or substitutions should all be covered within the protection scope of this application. Therefore, the protection scope of this application should be determined by the scope of the claims.

Claims

1. A rapid testing system for the comprehensive performance of cylindrical batteries, characterized in that, The system includes: Microcurrent pulse excitation module: It is used to pulse excite the battery and build a transient temperature field on the battery surface; Infrared imaging module: It is used to acquire battery thermal data based on transient temperature fields; Electrical signal acquisition module: It is used to acquire the electrical data of the battery; Thermoelectric coupling module: It is used to obtain thermoelectric coupling parameters based on electrical data and battery thermal data; these thermoelectric coupling parameters include DC internal resistance, AC impedance, thermal conductivity and DC internal resistance temperature coefficient; Risk labeling module: It is used to determine the risk type based on the comparison results of thermoelectric coupling parameters and preset thresholds.

2. The rapid testing system for the comprehensive performance of a cylindrical battery according to claim 1, characterized in that, The microcurrent pulse excitation module includes a DC pulse unit and a disturbance pulse unit; The DC pulse unit excites the battery using a single-pulse, single-excitation mode, with a pulse current amplitude of 40mA-60mA, a frequency of 0.1kHz-1kHz, a bandwidth of 0.01kHz-1kHz, and a pulse width of 8ms-12ms. The disturbance pulse unit excites the battery using a single-pulse, single-excitation mode, works synchronously with the DC pulse unit, and has a pulse current amplitude of 1mA-2mA, a frequency of 100kHz-1MHz, a bandwidth of 10kHz-50kHz, and a pulse width of 1us-2us.

3. The rapid testing system for the comprehensive performance of a cylindrical battery according to claim 2, characterized in that, The infrared imaging module includes an infrared scanning unit and a feature extraction unit. The infrared scanning unit is used to scan and capture the transient temperature of the battery surface. The feature extraction unit is used to determine the average temperature, maximum temperature, and temperature gradient of the battery surface based on the transient temperature of all points within the same sampling period, as battery thermal data.

4. The rapid testing system for the comprehensive performance of a cylindrical battery according to claim 3, characterized in that, The electrical data includes the current and voltage at both ends of the battery; The electrical data collected during the operation of the DC pulse unit is defined as DC electrical data; The electrical data collected by the disturbance pulse unit during operation is defined as AC electrical data.

5. The rapid testing system for the comprehensive performance of a cylindrical battery according to claim 4, characterized in that, The thermoelectric coupling module includes a data diagnostic unit, a DC internal resistance calculation unit, an AC impedance calculation unit, and an inversion and deduction unit. The data diagnostic unit is used to determine whether the battery thermal data is normal. The DC internal resistance calculation unit is used to obtain the DC internal resistance of the battery based on the DC electrical data when the battery thermal data is normal. The AC impedance calculation unit is used to analyze AC electrical data through fast Fourier transform to obtain the AC impedance of the battery. The inversion calculation unit is used to determine the thermal conductivity and DC internal resistance temperature coefficient of the battery based on the battery size, DC internal resistance, AC impedance and battery thermal data.

6. The rapid testing system for the comprehensive performance of a cylindrical battery according to claim 5, characterized in that, The process for determining whether the battery thermal data is normal includes: The pulse excitation is determined based on the actual output current value and pulse width of the DC pulse unit. If the pulse excitation exceeds the preset pulse threshold, it is determined that the current pulse excitation is inaccurate and the pulse excitation is repeated; otherwise, the pulse excitation is determined to be normal. After confirming that the pulse excitation is normal, it is determined whether the battery thermal data exceeds the preset temperature field threshold. If so, the battery thermal data is determined to be abnormal, that is, there is a transient temperature field unevenness; otherwise, the battery thermal data is determined to be normal. When the battery thermal data is determined to be abnormal, the battery is repeatedly pulse-excited using a DC pulse unit, and it is determined in turn whether the corresponding pulse excitation exceeds the preset threshold and whether the battery thermal data is normal. If the determination result of the battery thermal data is still abnormal, the battery is marked as a suspected damaged battery.

7. The rapid testing system for the comprehensive performance of a cylindrical battery according to claim 6, characterized in that, The process of obtaining the battery's DC internal resistance based on DC electrical data includes: The voltage and current at both ends of the battery are selected during the pulse stabilization period. The ratio of the absolute voltage fluctuation difference to the absolute current fluctuation difference at both ends of the battery is used as the ideal DC internal resistance of the battery. The corrected DC internal resistance is obtained based on the battery's ideal DC internal resistance and the average temperature during the pulse stabilization period. The calculation formula is as follows: ； In the formula, This is the corrected DC internal resistance. This is the temperature reference coefficient for the DC internal resistance of the battery. The average temperature. This is the standard reference temperature.

8. The rapid testing system for the comprehensive performance of a cylindrical battery according to claim 1, characterized in that, The process for obtaining the thermal conductivity includes: Construct a heat conduction model, which includes: ； In the formula, For temperature gradient, Thermal conductivity, The heat flux density is calculated as follows: ； In the formula, This represents the actual output current of the DC pulse unit. This represents the cross-sectional area of ​​the battery. The heat conduction model is iterated using the least squares method to obtain the predicted temperature gradient, and the gradient with the smallest error compared to the above temperature gradient is selected. The value is used as the thermal conductivity of the battery; The process for obtaining the DC internal resistance temperature coefficient includes: A temperature resistance characteristic model is constructed, which includes: ； In the formula, The DC internal resistance of the battery at 25°C. The temperature coefficient of DC internal resistance; Substituting the continuous ideal DC internal resistance and average temperature of the battery into the temperature resistance characteristic model, and performing linear regression fitting using the least squares method, the final value is determined based on the slope and intercept. The value is used as the temperature coefficient of the battery's DC internal resistance. The DC internal resistance calculation unit obtains the final DC internal resistance based on the battery's DC internal resistance temperature coefficient.

9. The rapid testing system for the comprehensive performance of a cylindrical battery according to claim 8, characterized in that, The process for determining the type of risk includes: Based on the actual output current of the DC pulse unit, the cross-sectional area and thermal conductivity of the battery, determine the maximum temperature gradient under the current operating conditions, and judge whether the temperature gradient is greater than the maximum temperature gradient. If so, it is determined that the battery has abnormal heat dissipation and indicates that the high temperature heat dissipation pressure is high; otherwise, it is determined that the battery heat dissipation is normal. Calculate the absolute deviation between the DC internal resistance temperature coefficient and the battery DC internal resistance temperature reference coefficient, and determine whether the absolute deviation exceeds the preset temperature coefficient threshold. If so, determine that the battery has abnormal internal resistance decay; otherwise, determine that the internal resistance decay is normal.

10. A rapid testing method for the comprehensive performance of a cylindrical battery, applied to the rapid testing system for the comprehensive performance of a cylindrical battery as described in claim 9, characterized in that... The method includes the following steps: S1. The DC pulse unit applies pulse excitation to the battery to construct a transient temperature field on the battery surface and obtains the battery thermal data based on the transient temperature field. S2. Collect the current and voltage at both ends of the battery as DC electrical data; S3. Obtain the corrected DC internal resistance of the battery based on the DC electrical data; S4. The disturbance pulse unit applies pulse excitation to the battery and collects the current and voltage at both ends of the battery as AC electrical data. S5. Analyze the AC electrical data using Fast Fourier Transform to obtain the AC impedance of the battery; S6. Determine the thermal conductivity and temperature coefficient of DC internal resistance of the battery based on the battery size, the corrected DC internal resistance, AC impedance and battery thermal data. S7. Obtain the final DC internal resistance based on the temperature coefficient of the battery's DC internal resistance. S8. Based on the actual output current of the DC pulse unit, the cross-sectional area and thermal conductivity of the battery, determine the maximum temperature gradient under the current operating conditions. If the temperature gradient is greater than the maximum temperature gradient, it is determined that the battery has an abnormal heat dissipation. Calculate the absolute deviation between the DC internal resistance temperature coefficient and the battery DC internal resistance temperature reference coefficient. If the absolute deviation exceeds the preset temperature coefficient threshold, it is determined that the battery has an abnormal internal resistance decay.

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