Battery micro-heat-based state of health evaluation system, method and computer device

Abstract

The application relates to a health state evaluation system, method and computer device based on battery micro-heat generation. The system comprises a high-vacuum subsystem for providing a high-vacuum environment; a charging and discharging subsystem for controlling the charging and discharging state of a to-be-tested battery according to preset charging and discharging conditions; a compensation subsystem located in the high-vacuum environment and used for receiving heat of the to-be-tested battery; a temperature measuring subsystem for detecting the real-time temperature of the compensation subsystem when the to-be-tested battery is in the charging and discharging state; a data processing subsystem for outputting corresponding compensation currents according to the real-time temperature and a reference temperature; and the compensation subsystem is further used for keeping the temperature of the compensation subsystem stable at the reference temperature according to the heat conducted by the to-be-tested battery and the compensation currents when the to-be-tested battery is in the charging and discharging state; and the data processing subsystem is further used for determining the health state of the to-be-tested battery according to the compensation currents when the to-be-tested battery is in different charging and discharging states. The system can accurately evaluate the health state of the battery.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of battery testing, in particular to a health state evaluation system, method and computer device based on battery micro-heat generation. BACKGROUND

[0002] In recent years, with the rapid development of electric vehicles and consumer electronics, the demand for lithium-ion batteries has increased dramatically. However, the heat generation analysis and heat management of batteries during charging and discharging are crucial for the evaluation of the life and health state of the battery.

[0003] However, the accuracy of the heat generation analysis of the battery during charging and discharging in the related art is low, resulting in inaccurate evaluation of the health state of the battery. SUMMARY

[0004] Therefore, it is necessary to provide a health state evaluation system, method and computer device based on battery micro-heat generation to accurately evaluate the health state of the battery.

[0005] In a first aspect, the present application provides a health state evaluation system based on battery micro-heat generation, which comprises:

[0006] A high-vacuum subsystem for providing a high-vacuum environment and accommodating a battery to be tested;

[0007] A charging and discharging subsystem connected to the battery to be tested, for controlling the charging and discharging state of the battery to be tested according to a predetermined charging and discharging condition;

[0008] A compensation subsystem in contact with the battery to be tested and located in the high-vacuum environment, for receiving heat from the battery to be tested;

[0009] A temperature measurement subsystem connected to the compensation subsystem, for detecting the real-time temperature of the compensation subsystem when the battery to be tested is in a charging and discharging state;

[0010] A data processing subsystem connected to the compensation subsystem, for outputting a corresponding compensation current according to the real-time temperature and a reference temperature;

[0011] The compensation subsystem is further configured to maintain the temperature of the compensation subsystem at the reference temperature according to the heat conducted by the battery to be tested and the compensation current when the battery to be tested is in a charging and discharging state;

[0012] The data processing subsystem is further configured to determine the health state of the battery to be tested according to the compensation current when the battery to be tested is in different charging and discharging states.

[0013] In one of the embodiments, the compensation subsystem comprises a heat-conducting structure, a stage and a temperature control circuit.

[0014] The heat-conducting structure wraps the battery under test and is located on the stage, and conducts the heat generated by the battery under test to the stage; the temperature control circuit is located inside the stage, and keeps the temperature of the stage stable at the reference temperature according to the compensation current.

[0015] In one of the embodiments, the temperature measurement subsystem comprises at least one thermocouple connected to the compensation subsystem, for detecting the real-time temperature of the compensation subsystem when the battery under test is in the charging and discharging state.

[0016] In a second aspect, a battery health state evaluation method based on micro-heat generation is provided, which is applied to the battery health state evaluation system based on micro-heat generation in any of the above embodiments, and the method comprises:

[0017] A high-vacuum environment is provided; wherein the battery under test and the compensation subsystem are located in the high-vacuum environment.

[0018] The charging and discharging state of the battery under test is controlled according to the preset charging and discharging conditions.

[0019] The real-time temperature of the compensation subsystem when the battery under test is in the charging and discharging state is detected.

[0020] According to the real-time temperature and the reference temperature, a corresponding compensation current is output to the compensation subsystem.

[0021] The health state of the battery under test is determined according to the compensation current when the battery under test is in different charging and discharging states.

[0022] In one of the embodiments, the determination of the health state of the battery under test according to the compensation current when the battery under test is in different charging and discharging states comprises:

[0023] The heat generation of the battery under test in different charging and discharging states is determined according to the compensation current when the battery under test is in different charging and discharging states.

[0024] The health state of the battery under test is determined according to the heat generation of the battery under test in different charging and discharging states and the preset reference heat generation of the battery under test in different charging and discharging states.

[0025] In one of the embodiments, the charging and discharging conditions comprise charging and discharging voltage, a plurality of charging and discharging rates and test time corresponding to each of the charging and discharging rates.

[0026] The control of the charging and discharging state of the battery under test according to the preset charging and discharging conditions comprises:

[0027] respectively control the to-be-tested battery to perform charging and discharging under the charging and discharging voltage and each of the charging and discharging rates until the charging and discharging time of the to-be-tested battery reaches the corresponding test time;

[0028] repeat the step of respectively controlling the to-be-tested battery to perform charging and discharging under the charging and discharging voltage and each of the charging and discharging rates until the charging and discharging time of the to-be-tested battery reaches the corresponding test time until the test times of the to-be-tested battery under each of the charging and discharging states reach a preset number of times.

[0029] In one of the embodiments, the determining the heat generation of the to-be-tested battery under different charging and discharging states according to the compensation currents of the to-be-tested battery under different charging and discharging states comprises:

[0030] the determining a plurality of candidate heat generations of the to-be-tested battery under different charging and discharging states according to the compensation currents of the to-be-tested battery under different charging and discharging states, wherein the number of the candidate heat generations of the to-be-tested battery under a charging and discharging state is the same as the test times of the to-be-tested battery under the corresponding charging and discharging state;

[0031] the determining at least one target heat generation of the to-be-tested battery under different charging and discharging states from each of the candidate heat generations of the to-be-tested battery under different charging and discharging states, wherein the heat generation fluctuation rate of the target heat generation is less than or equal to a preset fluctuation threshold;

[0032] the determining the heat generation of the to-be-tested battery under different charging and discharging states according to the average of each of the target heat generations of the to-be-tested battery under different charging and discharging states.

[0033] In one of the embodiments, the determining a plurality of candidate heat generations of the to-be-tested battery under different charging and discharging states according to the compensation currents of the to-be-tested battery under different charging and discharging states comprises:

[0034] the determining the refrigeration capacity of the compensation subsystem under different charging and discharging states of the to-be-tested battery according to the compensation currents of the to-be-tested battery under different charging and discharging states, a preset reference temperature, a preset Seebeck coefficient and a preset internal resistance of the compensation subsystem;

[0035] the determining the candidate heat generation of the to-be-tested battery under different charging and discharging states according to the refrigeration capacity of the compensation subsystem under different charging and discharging states of the to-be-tested battery.

[0036] In one of the embodiments, the determining the health state of the to-be-tested battery according to the heat generation of the to-be-tested battery under different charging and discharging states and the preset reference heat generation of the to-be-tested battery under different charging and discharging states comprises:

[0037] drawing a reference heat generation curve according to the reference heat generation of the battery to be tested under different charge and discharge states;

[0038] drawing a test heat generation curve of the battery to be tested according to the heat generation of the battery to be tested under different charge and discharge states;

[0039] calculating a reference heat generation area and a test heat generation area respectively according to the reference heat generation curve and the test heat generation curve of the battery to be tested;

[0040] determining the state of health of the battery to be tested according to the reference heat generation area and the test heat generation area.

[0041] In a third aspect, the present application provides a computer device, comprising a memory and a processor, the memory stores a computer program, and the processor implements the steps of the method described in any one of the above embodiments when executing the computer program.

[0042] The above-mentioned battery health state evaluation system, method and computer device based on micro heat generation of the battery, comprising a high vacuum subsystem, a charge and discharge subsystem, a compensation subsystem, a temperature measurement subsystem and a data processing subsystem. The high vacuum subsystem is used to provide a high vacuum environment and to accommodate the battery to be tested and the compensation subsystem to isolate external heat from interfering with the battery to be tested and the compensation subsystem. The temperature measurement subsystem is used to detect the real-time temperature of the compensation subsystem when the battery to be tested is in a charge and discharge state. The data processing subsystem is used to output a corresponding compensation current to the compensation subsystem according to the real-time temperature and the reference temperature, so that the compensation subsystem can stabilize at the reference temperature according to the heat conducted by the battery to be tested and the compensation current when the battery to be tested is in a charge and discharge state. Then, the data processing subsystem can determine the state of health of the battery to be tested according to the compensation current when the battery to be tested is in different charge and discharge states. First, the present application provides a high vacuum environment through the high vacuum subsystem, which can ensure the thermal stability during the measurement process and reduce external interference. Second, the present application indirectly calculates the heat generation of the battery to be tested by maintaining the compensation current of the compensation subsystem at the reference temperature, which can avoid the difficulty in calculating the specific heat capacity of the battery, and at the same time, since the specific heat capacity of the battery is not needed to calculate the heat generation of the battery, the accuracy of the calculation can be improved. Third, the present application involves obtaining comprehensive battery heat generation data when the battery to be tested is in different charge and discharge states. In summary, the battery health state evaluation system of the present application can accurately evaluate the state of health of the battery. BRIEF DESCRIPTION OF DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings in the following description only represent some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative effort.

[0044] Figure 1 Structure schematic diagram of a battery micro-heat-based health state evaluation system in an embodiment;

[0045] Figure 2 Structure schematic diagram of a battery micro-heat-based health state evaluation system in another embodiment;

[0046] Figure 3 Flow schematic diagram of a battery micro-heat-based health state evaluation method in an embodiment;

[0047] Figure 4 Flow schematic diagram of step S305 in an embodiment;

[0048] Figure 5 Flow schematic diagram of step S302 in an embodiment;

[0049] Figure 6 Flow schematic diagram of step S401 in an embodiment;

[0050] Figure 7 Flow schematic diagram of step S601 in an embodiment;

[0051] Figure 8 Flow schematic diagram of step S402 in an embodiment;

[0052] Figure 9 Heat generation curve diagram of a first battery to be tested, a second battery to be tested and a healthy battery in an embodiment. DETAILED DESCRIPTION

[0053] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The accompanying drawings show embodiments of the present application. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0054] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terms used in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application.

[0055] It is to be understood that the terms "first", "second", etc. can be used herein to describe various elements, but the elements should not be limited by these terms. The terms are only used to distinguish one element from another.

[0056] Spatially relative terms, such as "under", "below", "lower", "over", "upper" and the like, can be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the figures. For example, if a device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the exemplary term "below" can encompass both an orientation of above and below. The device can also be oriented in the other direction, and the spatially relative terms used herein are intended to encompass such additional orientations. It is to be understood that the spatially relative terms used herein, including up, down, front, back, right, left, and the like, are intended to be interpreted as described above.

[0057] It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element, or connected to the other element through intervening elements. In addition, "connected" as used in the following embodiments can be "electrically connected", "communicatively connected", or the like, if there is a transmission of electrical signals or data between the connected objects.

[0058] As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises", "comprising", "includes" and / or "including", or the like, when used in this specification, specify the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

[0059] As described in the background, in recent years, with the rapid development of electric vehicles and consumer electronics, the demand for lithium-ion batteries has increased dramatically. However, the heat generation analysis and heat management of the battery during charging and discharging are crucial to the life and safety reliability of the battery. At present, the commonly used battery heat generation measurement method is to monitor the temperature rise of the battery, and then calculate the heat generation by attaching a thermocouple to the surface of the battery. However, this method has the following three shortcomings: first, due to the presence of air, the heat generated inside the battery will diffuse into the air, resulting in inaccurate temperature measurement; second, the heat generated by the battery will have a certain delay in conducting out of the battery, and will spread from each surface of the battery, resulting in inaccurate temperature measurement; third, the use of thermocouples to measure the small amount of heat generated by the battery is not sensitive, and there will be a large error in the conversion of heat generation and heat dissipation. Therefore, the measurement method of the prior art is complex and has limited measurement accuracy, and cannot accurately evaluate the health status of the battery.

[0060] Based on the above reasons, in one exemplary embodiment, please refer to Figure 1 The present application provides a health status evaluation system based on battery micro-heat generation, which comprises a high-vacuum subsystem 11, a charging and discharging subsystem 12, a compensation subsystem 13, a temperature measurement subsystem 14 and a data processing subsystem 15.

[0061] The high-vacuum subsystem 11 is used to provide a high-vacuum environment and to accommodate the battery to be tested 20 and the compensation subsystem 13. The charging and discharging subsystem 12 is connected to the battery to be tested 20 and is used to control the charging and discharging state of the battery to be tested 20 according to the predetermined charging and discharging conditions. The compensation subsystem 13 is in contact with the battery to be tested 20 and is located in the high-vacuum environment, and is used to receive the heat of the battery to be tested 20. The temperature measurement subsystem 14 is connected to the compensation subsystem 13 and is used to detect the real-time temperature of the compensation subsystem 13 when the battery to be tested 20 is in the charging and discharging state. The data processing subsystem 15 is connected to the compensation subsystem 13 and is used to output the corresponding compensation current according to the real-time temperature and the reference temperature. The compensation subsystem 13 is also used to maintain the temperature of the compensation subsystem 13 at the reference temperature according to the heat conducted by the battery to be tested 20 and the compensation current when the battery to be tested 20 is in the charging and discharging state. The data processing subsystem 15 is also used to determine the health status of the battery to be tested 20 according to the compensation current when the battery to be tested 20 is in different charging and discharging states.

[0062] In the embodiment, when detecting the health state of the battery under test, first, the battery under test 20 is connected with the charge-discharge subsystem 12, the compensation subsystem 13 is connected with the temperature measuring subsystem 14, and the data processing subsystem 15 is connected with the compensation subsystem 13 and the temperature measuring subsystem 14 respectively. Then, the battery under test 20 and the compensation subsystem 13 are placed in the high-vacuum subsystem 11 together, the battery under test 20 contacts with the compensation subsystem 13, and the high-vacuum subsystem 11 is controlled to provide a high-vacuum environment for the battery under test 20 and the compensation subsystem 13 for testing, so as to isolate the interference of external heat on the battery under test 20 and the compensation subsystem 13. At the same time, the charge-discharge subsystem 12 is controlled to control the charge-discharge state of the battery under test 20 according to the preset charge-discharge condition, and the temperature measuring subsystem 14 is controlled to detect the real-time temperature of the compensation subsystem 13 when the battery under test 20 is in the charge-discharge state. The temperature measuring subsystem 14 can send the detected real-time temperature of the compensation subsystem 13 to the data processing subsystem 15, and the data processing subsystem 15 can deliver the compensation current to the compensation subsystem 13 according to the real-time temperature of the compensation subsystem 13 and the reference temperature of the compensation subsystem 13, so as to control the temperature of the compensation subsystem 13 to be stable at the reference temperature. The reference temperature of the compensation subsystem 13 refers to the temperature of the compensation subsystem 13 in the high-vacuum environment when the battery under test 20 does not conduct heat to the compensation subsystem 13.

[0063] In the high-vacuum environment, when the battery under test 20 is in the charge-discharge state, the heat generated by the battery under test 20 is conducted to the compensation subsystem 13, and the compensation subsystem 13 maintains the temperature constant under the action of the compensation current. That is, the heat generated by the battery under test 20 is offset by the refrigeration amount generated by the compensation subsystem 13 under the action of the compensation current. Therefore, in the present application, the heat generation amount of the battery under test 20 can be accurately determined by calculating the refrigeration amount of the compensation subsystem 13, and the health state of the battery under test 20 can be accurately evaluated according to the accurate heat generation amount of the battery under test 20.

[0064] The battery health state evaluation system based on the battery micro-heat generation comprises a high-vacuum subsystem 11, a charging and discharging subsystem 12, a compensation subsystem 13, a temperature measurement subsystem 14, and a data processing subsystem 15. The high-vacuum subsystem 11 is configured to provide a high-vacuum environment and accommodate the to-be-tested battery 20 and the compensation subsystem 13 to isolate the interference of external heat on the to-be-tested battery 20 and the compensation subsystem 13. The temperature measurement subsystem 14 is configured to detect the real-time temperature of the compensation subsystem 13 when the to-be-tested battery 20 is in a charging and discharging state. The data processing subsystem 15 is configured to output a corresponding compensation current to the compensation subsystem 13 according to the real-time temperature and the reference temperature, so that the compensation subsystem 13 is stabilized at the reference temperature according to the heat conducted by the to-be-tested battery 20 and the compensation current when the to-be-tested battery 20 is in the charging and discharging state. In this way, the data processing subsystem 15 can determine the health state of the to-be-tested battery 20 according to the compensation current when the to-be-tested battery 20 is in different charging and discharging states. First, the high-vacuum environment provided by the high-vacuum subsystem 11 can ensure the thermal stability during the measurement process and reduce external interference. Second, the compensation current for maintaining the compensation subsystem 13 at the reference temperature can indirectly calculate the heat generation of the to-be-tested battery 20, which can reduce the difficulty in calculating the heat index due to the difficulty in estimating the specific heat capacity of the battery, and can also improve the accuracy of the calculation since the specific heat capacity of the battery is not used to calculate the heat generation of the battery. Third, the application relates to the acquisition of battery heat generation data when the to-be-tested battery 20 is in different charging and discharging states. In summary, the battery health state evaluation system can accurately evaluate the health state of the battery.

[0065] In one exemplary embodiment, referring to Figure 2 The compensation subsystem 13 comprises a heat-conducting structure 131, a carrier table 132, and a temperature control circuit 133. The heat-conducting structure 131 wraps the to-be-tested battery 20 and is located on the carrier table 132, so as to conduct the heat generated by the to-be-tested battery 20 to the carrier table 132. The temperature control circuit 133 is located inside the carrier table 132, and is configured to maintain the temperature of the carrier table 132 at the reference temperature according to the compensation current.

[0066] The temperature measurement subsystem 14 comprises at least one thermocouple connected with the compensation subsystem 13, and is configured to detect the real-time temperature of the compensation subsystem 13 when the to-be-tested battery 20 is in a charging and discharging state. For example, the temperature measurement subsystem 14 comprises at least one T-type thermocouple, and the error rate of the T-type thermocouple is ±0.001℃.

[0067] The high-vacuum subsystem 11 can comprise a vacuum cover and a vacuum pump connected with each other.

[0068] In one example, the heat-conductive structure 131 can be a high-heat-conductive copper heat sink. When testing the battery under test, the high-heat-conductive copper heat sink can be used to tightly wrap the entire battery under test 20, and a thermocouple can be attached to the stage 132. Then, the battery under test 20 wrapped by the high-heat-conductive copper heat sink can be placed on the stage 132, and the stage 132 and the battery under test 20 wrapped by the high-heat-conductive copper heat sink can be placed in a vacuum chamber. After that, a vacuum pump can be started to perform vacuuming, and the vacuum degree can be lower than 10 - ³ Pa. Then, the battery under test 20 can be powered on by using the charge-discharge system 12, and the battery under test 20 can be controlled to be in a charge-discharge state. The health status of the battery under test 20 can be tested.

[0069] In one example embodiment, referring to Figure 3 , the application also provides a health status evaluation method based on battery micro-heat generation, which can be applied to the health status evaluation system based on battery micro-heat generation in any of the above embodiments. The method includes steps S301 to S305.

[0070] S301: providing a high-vacuum environment; wherein the battery under test and the compensation subsystem are located in the high-vacuum environment.

[0071] During testing, the heat-conductive structure 131 can be used to tightly wrap the entire battery under test 20, and a thermocouple can be attached to the stage 132. Then, the battery under test 20 wrapped by the heat-conductive structure 131 can be placed on the stage 132, and the stage 132 and the battery under test 20 wrapped by the heat-conductive structure 131 can be placed in a vacuum chamber. After that, a vacuum pump can be started to perform vacuuming, so that the vacuum degree in the vacuum chamber is lower than 10 - ³ Pa and remains.

[0072] S302: controlling the charge-discharge state of the battery under test according to a preset charge-discharge condition.

[0073] In the embodiment, the preset charging and discharging conditions can include a charging and discharging voltage, a charging and discharging rate and a test time of the battery under test 20. In an example, the charging and discharging voltage of the battery under test 20 can be between (1.0~1.2)*Vmin~(0.8~1.0)*Vmax, Vmin is the rated minimum voltage of the battery under test 20, and Vmax is the rated maximum voltage of the battery under test 20. The charging and discharging rate of the battery under test 20 can be 0.5C, 1C, 2C, 3C or 5C, wherein 1C means that the battery under test 20 is completely discharged or charged in one hour, 0.5C means that the battery under test 20 is completely discharged or charged in two hours, and 2C means that the battery under test 20 is completely discharged or charged in half an hour. The test time is the time of three working periods of the battery under test 20, specifically, one working period is that the battery under test 20 completes one charging and one discharging. The charging and discharging rate is the ratio of the charging and discharging current to the rated capacity of the battery under test 20. According to the charging and discharging rate and the rated capacity of the battery under test 20, the size of the charging and discharging current of the battery under test 20 under each charging and discharging rate can be calculated. By controlling the battery under test 20 to charge and discharge at different charging and discharging rates, the battery under test 20 can be controlled to be in different working states.

[0074] S303: detecting the real-time temperature of the compensation subsystem when the battery under test is in the charging and discharging state.

[0075] When the battery under test 20 is in the charging and discharging state, the battery under test 20 will generate heat, and the heat generated by the battery under test 20 will be conducted to the objective table 132 through the heat conduction structure 131, causing the temperature change of the objective table 132. Therefore, the real-time temperature of the compensation subsystem 13 when the battery under test 20 is in the charging and discharging state can be detected by the temperature measurement subsystem 14.

[0076] S304: outputting the corresponding compensation current to the compensation subsystem according to the real-time temperature and the reference temperature.

[0077] In the application, the temperature measurement subsystem 14 also sends the detected real-time temperature of the objective table 132 to the data processing subsystem 15 in real time, and then the data processing subsystem 15 can output the corresponding compensation current to the temperature control circuit 133 inside the objective table 132 according to the real-time temperature and the reference temperature of the objective table 132, so that the temperature control circuit 133 cools and the temperature of the objective table 132 returns to the reference temperature.

[0078] S305: determining the health state of the battery under test according to the compensation current when the battery under test is in different charging and discharging states.

[0079] It can be understood that the data processing subsystem 15 can derive the refrigeration power of the temperature control circuit 133 according to the compensation current output to the temperature control circuit 133, and further derive the refrigeration amount of the temperature control circuit 133. Since the object table 132 and the battery to be tested 20 wrapped by the heat conduction structure 131 are in a high vacuum environment, there is no interference of external heat, and the refrigeration amount of the temperature control circuit 133 is the heat generation amount of the battery to be tested 20 when the temperature of the object table 132 is stable at the reference temperature. According to the heat generation amount of the battery to be tested 20 under different charge and discharge states, it can be determined whether the heat generation of the battery to be tested 20 under each charge and discharge state is normal, and further determine the health status of the battery to be tested 20.

[0080] In one exemplary embodiment, referring to Figure 4 , step S305, determining the health status of the battery to be tested according to the compensation current of the battery to be tested under different charge and discharge states, including step S401 and step S402.

[0081] S401: determining the heat generation amount of the battery to be tested under different charge and discharge states according to the compensation current of the battery to be tested under different charge and discharge states.

[0082] Specifically, the refrigeration power of the temperature control circuit 133, i.e. the real-time heat generation power of the battery to be tested 20, can be calculated according to the compensation current output by the data processing subsystem 15 to the temperature control circuit 133 under different charge and discharge states of the battery to be tested 20, and further the heat generation amount of the battery to be tested 20 can be obtained.

[0083] S402: determining the health status of the battery to be tested according to the heat generation amount of the battery to be tested under different charge and discharge states and the preset reference heat generation amount of the battery to be tested under different charge and discharge states.

[0084] In the embodiment, the reference heat generation amount of the battery to be tested 20 can be obtained by testing the unused battery or the healthy battery produced in the same batch as the battery to be tested 20 by the battery health status evaluation method of the application. By comparing the heat generation amount of the battery to be tested 20 under different charge and discharge states with the preset reference heat generation amount of the battery to be tested under different charge and discharge states, the health status of the battery to be tested can be determined.

[0085] In one exemplary embodiment, referring to Figure 5 , step S302, controlling the charge and discharge state of the battery to be tested according to the preset charge and discharge condition, including step S501 and step S502.

[0086] S501: respectively controlling the battery to be tested to charge and discharge under the charge and discharge voltage and each charge and discharge rate until the charge and discharge time of the battery to be tested reaches the corresponding test time.

[0087] The charge-discharge conditions include a charge-discharge voltage, a plurality of charge-discharge rates, and a test time corresponding to each charge-discharge rate.

[0088] In one example, the charge-discharge voltage of the battery under test 20 can be between (1.0~1.2)*Vmin~(0.8~1.0)*Vmax, Vmin is the rated minimum voltage of the battery under test 20, Vmax is the rated maximum voltage of the battery under test 20, the charge-discharge rate of the battery under test 20 can be 0.5C, 1C, 2C, 3C, wherein 1C means that the battery under test 20 is completely discharged or charged in one hour, 0.5C means that the battery under test 20 is completely discharged or charged in two hours, 2C means that the battery under test 20 is completely discharged or charged in half an hour, and 3C means that the battery under test 20 is completely discharged or charged in twenty minutes. The test time can be the time of three working cycles of the battery under test 20, and one working cycle is one complete charging and discharging of the battery under test 20. The test time corresponding to the charge-discharge rate of 0.5C of the battery under test 20 is 12 hours, the test time corresponding to the charge-discharge rate of 1C of the battery under test 20 is 6 hours, the test time corresponding to the charge-discharge rate of 2C of the battery under test 20 is 3 hours, and the test time corresponding to the charge-discharge rate of 3C of the battery under test 20 is 2 hours.

[0089] Since the charge-discharge rate is the ratio of the charge-discharge current to the rated capacity of the battery under test 20, the size of the charge-discharge current of the battery under test 20 under each charge-discharge rate can be calculated according to the charge-discharge rate and the rated capacity of the battery under test 20. By controlling the battery under test 20 to charge and discharge at different charge-discharge rates, the battery under test 20 can be controlled to be in different working states.

[0090] S502: repeatedly performing the steps of respectively controlling the battery under test to charge and discharge at the charge-discharge voltage and each charge-discharge rate until the charge-discharge time of the battery under test reaches the corresponding test time, until the test number of the battery under test under each charge-discharge state reaches the preset number.

[0091] In the application, in order to reduce the test error, the battery under test 20 can be controlled to be tested multiple times under each charge-discharge state. For example, the battery under test 20 can be controlled to be tested multiple times under each charge-discharge state, and the heat generation value of the battery under test 20 in each test round in which the heat generation fluctuation rate is less than the preset threshold is taken as the heat generation value of the battery under test 20.

[0092] In one example embodiment, please refer to Figure 6 , step S401, determining the heat generation of the battery under test under different charge-discharge states according to the compensation current of the battery under test under different charge-discharge states, including step S601 and step S603.

[0093] S601: Determine multiple candidate heat generation amounts of the battery under test in different charge and discharge states according to the compensation currents of the battery under test in the different charge and discharge states, wherein the number of candidate heat generation amounts of the battery under test in a charge and discharge state is the same as the number of tests of the battery under test in the corresponding charge and discharge state.

[0094] In one example, when the battery under test 20 is tested, four charge and discharge conditions are set, corresponding to four charge and discharge states of the battery under test 20, and the four charge and discharge conditions are (U, 0.5C, 12h), (U, 1C, 6h), (U, 2C, 3h) and (U, 3C, 2h), wherein U is the charge and discharge voltage of the battery under test 20, nC is the charge and discharge rate of the battery under test 20, n = 0.5, 1, 2, 3, and h is hour. The battery under test 20 is tested multiple times according to each charge and discharge condition, and then for each charge and discharge condition, multiple heat generation values of the battery under test 20 can be obtained.

[0095] S602: Determine at least one target heat generation amount of the battery under test in different charge and discharge states from the candidate heat generation amounts of the battery under test in different charge and discharge states, wherein the heat generation fluctuation rate of the target heat generation amount is less than or equal to a preset fluctuation threshold.

[0096] Then, the heat generation fluctuation rate of the battery under test 20 in each test round is calculated according to the multiple heat generation values of the battery under test 20 in the charge and discharge state, wherein the heat generation fluctuation rate R H = (H nC -H nC ) / H nC , Hx is the heat generation amount of the battery under test 20 in a single test, i.e., the candidate heat generation amount, H 0.5C1 is the average value of the heat generation amounts of the battery under test in each test round in the same test state of the battery under test 20. In one example, for the charge and discharge condition (U, 0.5C, 12h), the battery under test 20 is controlled to be tested 5 times, and 5 candidate heat generation amounts H 0.5C2 , H 0.5C3 , H 0.5C4 , H 0.5C5 , H 0.5C1 is the candidate heat generation amount of the battery under test 20 in the first test round in the charge and discharge state, H 0.5C2 is the candidate heat generation amount of the battery under test 20 in the second test round in the charge and discharge state, H 0.5C3 is the candidate heat generation amount of the battery under test 20 in the third test round in the charge and discharge state, H 0.5C4 is the candidate heat generation amount of the battery under test 20 in the fourth test round in the charge and discharge state, and H 0.5C5 is the candidate heat generation amount of the battery under test 20 in the fifth test round in the charge and discharge state. H nC = (H0.5C1 +H 0.5C2 +H 0.5C3 +H 0.5C4 +H 0.5C5 ) / 5by which the heat generation fluctuation rate R of the battery 20 under the charging and discharging state can be calculated for each test round H . Then, the candidate heat generation corresponding to the test round with the heat generation fluctuation rate R H less than or equal to the preset fluctuation threshold is selected as the target heat generation of the battery 20 under the charging and discharging state.

[0097] S603: determining the heat generation of the battery under different charging and discharging states according to the average of the target heat generations of the battery under different charging and discharging states.

[0098] Then, the target heat generation of the battery 20 under the charging and discharging state can be averaged to obtain the heat generation of the battery 20 under the charging and discharging state.

[0099] In another example, the target heat generation of the battery 20 can also be determined without the heat generation fluctuation rate, for example, the battery 20 can be tested multiple times under each charging and discharging condition, and for each charging and discharging condition, multiple candidate heat generations of the battery 20 can be obtained. Then, for the candidate heat generations under each charging and discharging condition, one highest value and one lowest value are discarded, and the remaining candidate heat generations are taken as the target heat generation. Then, the target heat generation of the battery 20 under the charging and discharging state can be averaged to obtain the heat generation of the battery 20 under the charging and discharging state.

[0100] In an exemplary embodiment, please refer to Figure 7 , step S601, determining multiple candidate heat generations of the battery under different charging and discharging states according to the compensation currents of the battery under different charging and discharging states, including step S701 and step S702.

[0101] S701: determining the refrigeration capacity of the compensation subsystem under different charging and discharging states of the battery according to the compensation currents of the battery under different charging and discharging states, the preset reference temperature, the preset Seebeck coefficient and the preset internal resistance of the compensation subsystem.

[0102] In the embodiment, the refrigeration power of the compensation subsystem under different charging and discharging states of the battery can be determined according to the compensation currents of the battery under different charging and discharging states, the preset reference temperature, the preset Seebeck coefficient and the internal resistance of the temperature control circuit 133 in the compensation subsystem, and the refrigeration capacity of the compensation subsystem under different charging and discharging states of the battery can be determined according to the refrigeration power. Wherein, Qc=STI-RI 2Qc is the cooling power, S is the preset Seebeck coefficient, T is the reference temperature, I is the compensation current, and R is the sum of the internal resistance of the temperature control circuit 133.

[0103] S702: Determine the candidate heat generation of the battery under test in different charge and discharge states according to the cooling capacity of the compensation subsystem when the battery under test is in different charge and discharge states.

[0104] Since the stage 132 and the battery under test 20 wrapped by the heat-conducting structure 131 are in a high-vacuum environment, there is no interference of external heat, and when the temperature of the stage 132 is stabilized at the reference temperature, the cooling capacity of the temperature control circuit 133 is the heat generation of the battery under test 20. Further, the candidate heat generation of the battery under test in different charge and discharge states can be determined according to the cooling capacity of the temperature control circuit 133 when the battery under test is in different charge and discharge states.

[0105] In an exemplary embodiment, please refer to Figure 8 , step S402, determine the health status of the battery under test according to the heat generation of the battery under test in different charge and discharge states and the preset reference heat generation of the battery under test in different charge and discharge states, including steps S801 to S804.

[0106] S801: Draw a reference heat generation curve according to the reference heat generation of the battery under test in different charge and discharge states.

[0107] The abscissa of the reference heat generation curve is the charge and discharge rate, and the ordinate is the heat generation. According to the preset reference heat generation of the battery under test in different charge and discharge states, a curve representing the relationship between the charge and discharge rate corresponding to each charge and discharge state and the reference heat generation corresponding to each charge and discharge state, i.e. the reference heat generation curve, can be drawn.

[0108] S802: Draw a test heat generation curve of the battery under test according to the heat generation of the battery under test in different charge and discharge states.

[0109] Similarly, the abscissa of the test heat generation curve is the charge and discharge rate, and the ordinate is the heat generation. According to the test heat generation of the battery under test in different charge and discharge states, a curve representing the relationship between the charge and discharge rate corresponding to each charge and discharge state and the heat generation corresponding to each charge and discharge state, i.e. the test heat generation curve, can be drawn.

[0110] S803: Calculate the reference heat generation area and the test heat generation area according to the reference heat generation curve and the test heat generation curve of the battery under test, respectively.

[0111] Then, the reference heat generation area of the battery under test can be calculated according to the reference heat generation curve of the battery under test, and the test heat generation area can be calculated according to the test heat generation curve of the battery under test.

[0112] S804: Determine the health state of the battery under test according to the reference heat generation area and the test heat generation area.

[0113] Further, the reference heat generation area and the test heat generation area can be compared, and the health state of the battery under test 20 is determined according to the ratio of the reference heat generation area and the test heat generation area, for example, the reference heat generation area is S0, the test heat generation area is Sn, if Sn≤2S0, it can be judged that the health state of the battery under test 20 is high; if 2S0<Sn<5S0, it can be judged that the health state of the battery under test 20 is medium; if Sn≥5S0, it can be judged that the health state of the battery under test 20 is low.

[0114] In a detailed embodiment, if it is necessary to evaluate the health state of two batteries under test (the first battery under test and the second battery under test), the first battery under test, the second battery under test, the healthy battery and the battery health state evaluation system of the application can be prepared in advance.

[0115] First, the entire healthy battery is tightly wrapped with the heat conduction structure 131, and the thermocouple is attached to the object table 132, then the healthy battery wrapped by the heat conduction structure 131 is placed on the object table 132, and the object table 132 and the healthy battery wrapped by the heat conduction structure 131 are placed in the vacuum chamber, then the vacuum pump is started to perform vacuum pumping, so that the vacuum degree in the vacuum chamber is lower than 10 - Pa and is maintained, then the healthy battery is powered on by using the charge-discharge system, the charge-discharge voltage of the healthy battery is set to V, the charge-discharge rate is set to 0.5C, 1C, 2C and 3C respectively, each charge-discharge rate is cycled for 3 weeks, and the stable heat generation value Hx under different charge-discharge rates is recorded in real time, and the heat generation fluctuation rate R H ≤15%, finally, the average value of the stable heat generation of the healthy battery under each current density for 3 weeks is taken as the reference heat generation.

[0116] First, the entire healthy battery is tightly wrapped with the heat conduction structure 131, and the thermocouple is attached to the object table 132, then the healthy battery wrapped by the heat conduction structure 131 is placed on the object table 132, and the object table 132 and the healthy battery wrapped by the heat conduction structure 131 are placed in the vacuum chamber, then the vacuum pump is started to perform vacuum pumping, so that the vacuum degree in the vacuum chamber is lower than 10 - Pa and is maintained, then the healthy battery is powered on by using the charge-discharge system, the charge-discharge voltage of the healthy battery is set to U, the charge-discharge rate is set to 0.5C, 1C, 2C and 3C respectively, each charge-discharge rate is cycled for 3 weeks, and the stable heat generation value Hx under different charge-discharge rates is recorded in real time, and the heat generation fluctuation rate R H≤15%, the heat generation of the healthy battery under each current density is taken as the average value of the stable heat generation in 3 weeks as the reference heat generation, and the reference heat generation H of the healthy battery under each charge and discharge rate is recorded respectively 0.5C , H 1C , H 2C , H 3C . Among them, the data acquisition frequency is 2 points per second, and the heat generation resolution is ≥10 - ³ J.

[0117] After obtaining the reference heat generation of the healthy battery under each charge and discharge rate, the first test battery can be tested. Similarly, the entire first test battery is tightly wrapped with the heat conduction structure 131, and the thermocouple is attached to the object table 132, and then the first test battery wrapped by the heat conduction structure 131 is placed on the object table 132, and the object table 132 and the first test battery wrapped by the heat conduction structure 131 are placed in the vacuum cover, and then the vacuum pump is started to perform vacuum pumping, so that the vacuum degree in the vacuum cover is lower than 10 - ³ Pa and remains, then the first test battery is powered on by using the charge and discharge system, the charge and discharge voltage of the first test battery is set to U, the charge and discharge rate is set to 0.5C, 1C, 2C and 3C respectively, each charge and discharge rate is cycled for 3 weeks, and the stable heat generation value Hx under different charge and discharge rates is recorded in real time, and the heat generation fluctuation rate R H ≤15%, the target heat generation of the first test battery under each current density is taken as the average value of the stable heat generation in 3 weeks as the heat generation of the first test battery, and the heat generation H of the first test battery under each charge and discharge rate is recorded respectively 0.5C , H 1C , H 2C , H 3C . Among them, the data acquisition frequency is 2 points per second, and the heat generation resolution is ≥10 - ³ J.

[0118] After obtaining the heat generation of the first test battery under each charge and discharge rate, the second test battery can be tested. Similarly, the entire second test battery is tightly wrapped with the heat conduction structure 131, and the thermocouple is attached to the object table 132, and then the second test battery wrapped by the heat conduction structure 131 is placed on the object table 132, and the object table 132 and the second test battery wrapped by the heat conduction structure 131 are placed in the vacuum cover, and then the vacuum pump is started to perform vacuum pumping, so that the vacuum degree in the vacuum cover is lower than 10 - ³ Pa and remains, then the second test battery is powered on by using the charge and discharge system, the charge and discharge voltage of the second test battery is set to U, the charge and discharge rate is set to 0.5C, 1C, 2C and 3C respectively, each charge and discharge rate is cycled for 3 weeks, and the stable heat generation value Hx under different charge and discharge rates is recorded in real time, and the heat generation fluctuation rate RH ≤15%, the target heat generation of the second battery under each current density is taken as the average value of the heat generation of the second battery under each current density in the last 3 weeks, and the heat generation of the second battery under each current density is recorded as H 0.5C , H 1C , H 2C , H 3C . Wherein, the data acquisition frequency is 2 points per second, and the heat generation resolution is ≥10 -3 J.

[0119] Finally, according to the heat generation of the first battery under each charge and discharge rate, the heat generation of the second battery under each charge and discharge rate, and the reference heat generation of the healthy battery under each charge and discharge rate, a heat generation curve can be drawn. In one example, the heat generation curve can be as shown in Figure 9 , respectively, the heat area Sn of the battery under test and S0 are compared, if Sn≤2S0, it can be judged that the health status of the battery under test 20 is high; if 2S0<Sn<5S0, it can be judged that the health status of the battery under test 20 is medium; if Sn≥5S0, it can be judged that the health status of the battery under test 20 is low.

[0120] As shown in Figure 9 , the test heat generation area of the first battery under test S1=50.94; the test heat generation area of the second battery under test S2=14.32; the reference heat generation area of the healthy battery S0=7.18; wherein, S1 / S0=7.09, therefore, the health status of the S1 battery can be identified as low; S2 / S0=1.99, therefore, the health status of the S2 battery can be identified as high.

[0121] It should be understood that, although each step in the flowchart of Figures 3-8 is shown in sequence according to the arrow, these steps are not necessarily executed in sequence according to the arrow. Unless otherwise specified herein, the execution of these steps is not strictly limited in sequence, and these steps can be executed in other sequences. Moreover, Figures 3-8 At least part of the steps in may include multiple steps or stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution sequence of these steps or stages is not necessarily sequential, but can be executed in rotation or alternation with at least part of other steps or steps or stages in other steps.

[0122] In one embodiment, a computer device is provided, comprising a memory and a processor, the memory stores a computer program, and the processor executes the computer program to realize the steps of the method in any of the above embodiments.

[0123] In one embodiment, a computer readable storage medium is provided, having stored thereon a computer program, which, when executed by a processor, implements the steps of the method of any of the above embodiments.

[0124] A person of ordinary skill in the art can understand that all or part of the processes in the above-mentioned embodiments can be completed by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer readable storage medium, and when executed, can include the processes of the above-mentioned embodiments. Any reference to memory, storage, 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 or optical memory. Volatile memory can include random access memory (RAM) or external cache memory. As an illustration but not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM).

[0125] In the description of the present specification, the description of the terms "some embodiments", "other embodiments", "ideal embodiments" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiments or examples are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example.

[0126] The technical features of the above embodiments can be combined in any way. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described, but as long as the combinations of the technical features do not contradict, they should be considered as within the scope of the present application.

[0127] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the scope of protection of the patent of the present application should be subject to the appended claims.

Claims

1. A battery micro-heat-based state of health assessment system, characterized in that, The system comprises: a high-vacuum subsystem configured to provide a high-vacuum environment and to accommodate a battery to be tested; a charge-discharge subsystem connected to the battery to be tested and configured to control a charge-discharge state of the battery to be tested according to preset charge-discharge conditions; a compensation subsystem in contact with the battery to be tested and located in the high-vacuum environment, and configured to receive heat generated by the battery to be tested; a temperature measurement subsystem connected to the compensation subsystem and configured to detect a real-time temperature of the compensation subsystem when the battery to be tested is in the charge-discharge state; a data processing subsystem connected to the compensation subsystem and configured to output a corresponding compensation current according to the real-time temperature and a reference temperature; and the compensation subsystem is further configured to keep the temperature of the compensation subsystem stable at the reference temperature according to the heat generated by the battery to be tested and the compensation current when the battery to be tested is in the charge-discharge state, and the heat generated by the battery to be tested is offset by a refrigeration amount generated by the compensation subsystem under the action of the compensation current. The data processing subsystem is further configured to determine a health state of the battery to be tested according to the compensation current when the battery to be tested is in different charge-discharge states.

2. The battery micro-heat-based state of health evaluation system of claim 1, wherein, The compensation subsystem comprises a heat-conducting structure, a stage, and a temperature control circuit. The heat-conducting structure wraps the battery to be tested and is located on the stage, and the heat generated by the battery to be tested is conducted to the stage; the temperature control circuit is located inside the stage and keeps the temperature of the stage stable at the reference temperature according to the compensation current.

3. The battery micro-heat-based state of health evaluation system of claim 1, wherein The temperature measurement subsystem comprises at least one thermocouple connected to the compensation subsystem and configured to detect the real-time temperature of the compensation subsystem when the battery to be tested is in the charge-discharge state.

4. A method for evaluating the state of health of a battery based on micro-heat generation, characterized by, The method is applied to the health state evaluation system based on battery micro-heat generation according to any one of claims 1-3, and the method comprises: providing a high-vacuum environment, wherein the battery to be tested and the compensation subsystem are located in the high-vacuum environment; controlling a charge-discharge state of the battery to be tested according to preset charge-discharge conditions; detecting a real-time temperature of the compensation subsystem when the battery to be tested is in the charge-discharge state; outputting a corresponding compensation current to the compensation subsystem according to the real-time temperature and a reference temperature, wherein the heat generated by the battery to be tested is offset by a refrigeration amount generated by the compensation subsystem under the action of the compensation current; and determining a health state of the battery to be tested according to the compensation current when the battery to be tested is in different charge-discharge states.

5. The battery micro-heat-based state of health evaluation method according to claim 4, wherein, The determination of the health state of the battery to be tested according to the compensation current when the battery to be tested is in different charge-discharge states comprises: determining heat generation amounts of the battery to be tested in different charge-discharge states according to the compensation current when the battery to be tested is in the different charge-discharge states; determining the health state of the battery to be tested according to the heat generation amounts of the battery to be tested in the different charge-discharge states and preset reference heat generation amounts of the battery to be tested in the different charge-discharge states.

6. The battery micro-heat-based state of health evaluation method according to claim 5, wherein, The charge-discharge conditions comprise charge-discharge voltages, a plurality of charge-discharge rates, and test times corresponding to the charge-discharge rates. The method comprises the following steps: The method comprises the following steps: The method comprises the following steps:

7. The battery micro-heat-based state of health evaluation method according to claim 6, wherein, The method comprises the following steps: The method comprises the following steps: The method comprises the following steps: The method comprises the following steps:

8. The battery micro-heat-based state of health evaluation method according to claim 7, wherein, The method comprises the following steps: The method comprises the following steps: The method comprises the following steps: 9.The battery micro-heat-based state of health evaluation method of claim 5, wherein, The method comprises the following steps: The method comprises the following steps: The method comprises the following steps: The method comprises the following steps: The method comprises the following steps: 10.A computer device, comprising a memory and a processor, wherein the memory stores a computer program, and the computer device is configured to perform the method according to any one of claims 1-9. 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