Detection method and device of power battery liquid cooling system, storage medium and equipment

Abstract

The invention provides a power battery liquid cooling system detection method and device, a storage medium and equipment. The detection method comprises the steps that when the temperature of a target battery cell is equal to the temperature T0 and the temperature of a liquid inlet of the liquid cooling system is larger than or equal to the temperature T1, the temperature of a liquid outlet of the liquid cooling system is collected, and the temperature T0 is smaller than the temperature of the battery cell when the liquid cooling system is started; and in a first time period, whether the temperature of the liquid outlet is abnormal or not is judged, and if yes, it is judged that the liquid cooling system is abnormal.

Description

Technical Field

[0001] The present invention relates to the field of liquid cooling systems for vehicle power batteries, and in particular to a detection method, device, storage medium and equipment for a liquid cooling system for a power battery. Background Art

[0002] At present, the power battery cooling methods used in the electric vehicle industry are mainly divided into air cooling, liquid cooling and direct cooling. Among them, the liquid cooling system has become the most mainstream cooling method due to its better heat exchange capacity, heat exchange consistency and battery sealing.

[0003] When the battery is bumped, the liquid cooling system may be mechanically deformed, and in severe cases may even cause leakage, which can lead to safety issues such as reduced insulation and short circuit of the battery cells. How to detect and identify damage to the cooling system in advance is one of the problems that the industry needs to solve urgently. Summary of the invention

[0004] The purpose of the present invention is to provide an implementation basis for the detection means to be carried out for the mechanical deformation problem of the vehicle power battery liquid cooling system in a simple, fast and accurate manner.

[0005] In addition, the present invention is also intended to solve or alleviate other technical problems existing in the prior art.

[0006] The present invention solves the above-mentioned problems by providing a detection method, device, storage medium and equipment for a power battery liquid cooling system. Specifically, according to one aspect of the present invention, it provides:

[0007] A detection method for a power battery liquid cooling system, wherein the detection method comprises:

[0008] When the target battery cell temperature is equal to temperature T0 and the liquid inlet temperature of the liquid cooling system is greater than or equal to temperature T1, collecting the liquid outlet temperature of the liquid cooling system, wherein temperature T0 is less than the battery cell temperature when the liquid cooling system is turned on;

[0009] In the first time period, it is determined whether the temperature of the liquid outlet is abnormal, and if so, it is determined that the liquid cooling system is abnormal.

[0010] Optionally, according to an embodiment of the present invention, detecting whether the current liquid outlet temperature is abnormal includes at least one of the following situations:

[0011] In response to detecting that the temperature of the liquid outlet after the first time period is equal to or greater than the temperature T 2异常 , determining that the temperature of the liquid outlet is abnormal;

[0012] In response to detecting that a fluctuation of the temperature of the liquid outlet within the first time period is equal to or greater than a fluctuation threshold, determining that the temperature of the liquid outlet is abnormal;

[0013] In response to detecting that the temperature of the liquid outlet during the first time period is equal to or greater than the temperature T 2异常 , determining that the temperature of the liquid outlet is abnormal.

[0014] Optionally, according to an embodiment of the present invention, before determining that the liquid cooling system is abnormal, the method further includes:

[0015] In response to the abnormal temperature of the liquid outlet, obtaining the current temperature of the liquid inlet;

[0016] In response to the difference between the liquid outlet temperature and the current liquid inlet temperature being greater than or equal to the temperature difference ΔT 异常 , it is determined that the liquid cooling system is abnormal.

[0017] Optionally, according to one embodiment of the present invention, the temperature T 2异常 Determined based on the following method:

[0018] Obtaining abnormal temperatures of multiple liquid outlets of at least one power battery having an abnormal liquid cooling system;

[0019] Calculate the average value of abnormal temperatures of multiple liquid outlets and use the average value as the temperature T 2异常 .

[0020] Optionally, according to an embodiment of the present invention, after determining that the liquid cooling system is abnormal, the method further includes:

[0021] An alarm is sent to the cloud, so that the cloud determines again whether the liquid cooling system is abnormal based on the alarm.

[0022] Optionally, according to an embodiment of the present invention, before determining that the liquid cooling system is abnormal, the method further includes:

[0023] In response to the temperature difference between the liquid outlet temperature and the liquid inlet temperature being equal to or greater than the temperature difference ΔT 异常 and temperature difference ΔT 正常 The average value of is used to determine that the liquid cooling system is abnormal.

[0024] Optionally, according to an embodiment of the present invention, the detection method is executed when the fluctuation of the inlet current or the supply current of the vehicle power battery is less than the fluctuation threshold within a certain period of time.

[0025] Optionally, according to an embodiment of the present invention, the detection method is performed when the vehicle is in a fast charging process.

[0026] Optionally, according to an embodiment of the present invention, the temperature difference between temperature T0 and temperature T1 is greater than 20 degrees Celsius.

[0027] Optionally, according to an embodiment of the present invention, the target cell temperature is selected as the highest cell temperature among the cells of the power battery.

[0028] Optionally, according to an embodiment of the present invention, during the first time period, the target battery cell temperature and the liquid inlet temperature of the liquid cooling system are monitored;

[0029] In response to a change in any one of the target battery cell temperature and the liquid inlet temperature of the liquid cooling system exceeding a change threshold, the detection method is re-executed.

[0030] According to another aspect of the present invention, the present invention provides a detection device for a power battery liquid cooling system, wherein the detection device comprises:

[0031] A collection module, wherein when the target battery cell temperature is equal to temperature T0 and the liquid inlet temperature of the liquid cooling system is equal to temperature T1, the collection module collects the liquid outlet temperature of the liquid cooling system, wherein temperature T0 is less than the battery cell temperature when the liquid cooling system is turned on;

[0032] A judgment module is used to judge whether the temperature of the liquid outlet is abnormal within a first time period, and if so, it is determined that the liquid cooling system is abnormal.

[0033] According to another aspect of the present invention, the present invention provides a computer-readable storage medium, on which a computer program is stored, wherein the computer program implements any of the above-mentioned detection methods when executed by a processor.

[0034] According to another aspect of the present invention, the present invention provides a computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements any one of the above-mentioned detection methods when executing the computer program.

[0035] The benefits of the provided detection method, device, storage medium and equipment for the power battery liquid cooling system include: avoiding battery safety issues caused by bumps and collisions; and high verification coverage. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The above and other features of the present invention will become apparent with reference to the accompanying drawings, in which:

[0037] Figure 1 A schematic flow chart of a detection method for a power battery liquid cooling system according to the present invention is shown;

[0038] Figure 2 A partial structural schematic diagram of a power battery liquid cooling system according to the present invention is shown;

[0039] Figure 3 Shown according to Figure 2 A schematic diagram of an enlarged view of the cold plate end;

[0040] Figure 4 A graph showing the difference in coolant outlet temperature between a normal battery and a battery with a damaged liquid cooling system during fast charging at the same cell temperature and liquid inlet temperature; and

[0041] Figure 5 A schematic structural diagram of a detection device for a power battery liquid cooling system according to the present invention is shown. DETAILED DESCRIPTION

[0042] It is easy to understand that according to the technical solution of the present invention, without changing the essential spirit of the present invention, a person skilled in the art can propose a variety of interchangeable structural modes and implementation modes. Therefore, the following specific implementation modes and drawings are only exemplary descriptions of the technical solution of the present invention, and should not be regarded as the whole of the present invention or as a limitation or restriction to the technical solution of the present invention.

[0043] The directional terms such as up, down, left, right, front, back, front, back, top, bottom, etc. mentioned or may be mentioned in this specification are defined relative to the structures shown in the drawings. They are relative concepts and may change accordingly according to their different positions and different usage states. Therefore, these or other directional terms should not be interpreted as restrictive terms. In addition, the terms "first", "second", "third", etc. or similar expressions are only used for description and distinction purposes, and cannot be understood as indicating or implying the relative importance of the corresponding components.

[0044] refer to Figure 1 , Figure 2 and Figure 3 , respectively showing a flow chart of a detection method for a power battery liquid cooling system according to the present invention, a partial structural chart of a power battery liquid cooling system according to the present invention, and Figure 2 The schematic diagram of the cold plate end is an enlarged view. It should be understood that Figure 1 The rounded rectangles above and below represent the beginning and end of the method flow, respectively, and Y represents the judgment result is yes.

[0045] The detection method is used for a power battery liquid cooling system, wherein the detection method comprises:

[0046] S1: When the target battery cell temperature is equal to temperature T0 and the liquid inlet temperature of the liquid cooling system is greater than or equal to temperature T1, collecting the liquid outlet temperature of the liquid cooling system, wherein temperature T0 is less than the battery cell temperature when the liquid cooling system is turned on;

[0047] S2: In the first time period, determine whether the temperature of the liquid outlet is abnormal, and if so, determine that the liquid cooling system is abnormal.

[0048] It should be noted that the naming of various method steps in this article is only for the purpose of distinction and convenience of reference, and does not mean that there must be a difference in the order of sequence among these method steps (or the sub-step segments described in the text of each method step) (unless explicitly stated). They can adjust the implementation order according to actual conditions, or even be executed simultaneously.

[0049] It should be understood that the vehicle herein can be a hybrid vehicle or a pure electric vehicle. Generally speaking, when the temperature of the power battery cell is higher than a certain preset value, the whole vehicle will automatically intervene, that is, automatically turn on the liquid cooling system for the power battery to protect the power battery from heat dissipation. Therefore, in order to enable the calibration method to be implemented smoothly without this factor, the technical solution defines that the temperature T0 is less than the cell temperature when the liquid cooling system is turned on to avoid the intervention of the whole vehicle. Thus, the tester can manually enable the battery management system to turn on the liquid cooling system of the power battery to perform the method execution process. Those skilled in the art know that the values ​​of the parameters increased in this article are selected according to the specific vehicle type and model. For example, if the whole vehicle intervenes and actively turns on the liquid cooling system for the power battery when the cell temperature of the power battery is 40 degrees Celsius, the temperature T0 can be set to about 35 degrees, and the temperature T1 is less than the temperature T0, so that the battery cell can transfer its heat to the coolant to complete its own cooling and heat dissipation. In addition, the request for temperature T1 may be completed by a battery monitoring system or a battery control system of the vehicle, so that the battery monitoring system monitors damage to the liquid cooling system.

[0050] Here we briefly explain the power battery liquid cooling system. Figure 2 and Figure 3 The vehicle power battery assembly 90 includes an upper cover 91, a power battery 92 and a box 93, wherein the power battery can be composed of multiple modules, each of which is composed of multiple cells. The box has a storage space for accommodating the power battery and can be closed by the upper cover, so that the box and the upper cover form a shell for protecting the power battery. A cold plate 94 and a bottom guard plate 95 of a liquid cooling system are arranged under the box, wherein at the end of the cold plate ( Figure 2The bottom plate (left end) is constructed with a liquid inlet 941 and a liquid outlet 942 for inputting and outputting coolant of the liquid cooling system, respectively, thereby enabling heat exchange with the power battery, and the bottom guard plate is used to protect the cold plate and the components thereon. It can be seen that in this example, one liquid inlet and a corresponding liquid outlet serve an entire power battery. However, it should be understood that in this example, the power battery structure, the local structure of the liquid cooling system, and the connection and positional relationship between the power battery and the liquid cooling system are merely exemplary and are only for illustrative purposes. Those skilled in the art can make adaptive modifications to the above aspects according to actual needs and requirements, and they can still be applicable to the various methods, devices and equipment involved in this article.

[0051] It should also be understood that in order to make the test results more accurate, the control variables can be used to maintain the coolant inlet temperature and the target battery cell temperature unchanged or within an allowable range of variation, so that the coolant outlet temperature can basically only change with the change of the coolant flow rate (or the amount of heat exchange), so as to more accurately distinguish between abnormal and normal liquid cooling systems. To this end, those skilled in the art know that the above-mentioned temperature control can be achieved through certain measures. For example, the vehicle controller maintains the coolant inlet temperature, and the vehicle's battery control system can request the inlet temperature, while the target battery cell temperature is usually maintained unchanged or within an acceptable range during the above-defined working process, and its temperature will only increase in the case of long-term operation.

[0052] According to the technical solution, the collected liquid outlet temperature of the liquid cooling system is used as a criterion for judging whether the liquid cooling system is abnormal. This detection method involves fewer physical quantities and controls variables. Therefore, the method is simple, fast and accurate, and can achieve the purpose of the present invention. It can identify abnormal liquid cooling systems at an early stage, thereby avoiding possible safety risks of subsequent batteries.

[0053] Optionally, the target cell temperature is selected from the cell temperature with the highest temperature among the cells of the power battery. Generally speaking, a power battery is composed of multiple modules, and the module includes multiple cells assembled together. That is to say, the power battery may include multiple cells. Therefore, there may be multiple reference methods for determining the cell temperature. For example, the average temperature of all cells of the power battery is selected as the cell temperature, or the most extreme cell temperature among all cells is selected. In some embodiments of the present disclosure, the cell temperature is selected from the cell temperature with the highest temperature among the cells of the power battery. This selection method is more suitable for practical application scenarios, because in the field of power battery heat dissipation, the cell with the highest temperature is the one that needs heat dissipation the most, and it also has the highest safety requirements, and can be regarded as a boundary value. Thus, the power battery liquid cooling system can be detected and screened to the maximum extent and in a targeted manner. Of course, if necessary, the method can also be implemented in different dimensions (such as extreme cell temperature, average cell temperature) or for multiple different cells to obtain a more comprehensive result.

[0054] In some embodiments of the present disclosure, detecting whether the current liquid outlet temperature is abnormal includes at least one of the following situations:

[0055] S21: In response to detecting that the temperature of the liquid outlet after the first time period is equal to or greater than the temperature T 2异常 , determining that the temperature of the liquid outlet is abnormal;

[0056] S22: in response to detecting that the fluctuation of the temperature of the liquid outlet within the first time period is equal to or greater than the fluctuation threshold, determining that the temperature of the liquid outlet is abnormal;

[0057] S23: In response to detecting that the temperature of the liquid outlet in the first time period is equal to or greater than the temperature T 2异常 , determining that the temperature of the liquid outlet is abnormal.

[0058] It can be seen that the present technical solution exemplarily provides three methods for determining abnormal temperature of the liquid outlet. 2异常 It can be determined based on the power battery with abnormal liquid cooling system. That is to say, the inspection personnel can first collect the temperature T of the power battery with abnormal liquid cooling system. 2异常, the value can be stored in the cloud or on-board, etc. and retrieved during the detection process. As described in the background technology, the abnormality of the liquid cooling system includes mechanical deformation of the liquid cooling system (for example, when it is bumped), or blockage caused by other forms. In the event of an abnormality in the liquid cooling system, the flow rate of the coolant will slow down. As a result, the heat exchange time between the coolant and the battery cell will be longer than normal, and the heat exchange amount will be greater. Therefore, the temperature of the coolant at the outlet will be higher than normal. Therefore, it can be known that one of the technical concepts of the present technical solution is to compare the outlet temperature T of the coolant in the abnormal liquid cooling system. 2异常 , to prepare for the actual detection method. In the actual detection, the outlet temperature of the coolant is detected (at one or more time points after the first time period) and compared with the outlet temperature T 2异常 By comparing, we can know whether the current power battery liquid cooling system is abnormal. This method involves fewer physical quantities, controls variables, and each temperature is relatively easy to collect. Therefore, this method is simple, fast and accurate, can achieve the purpose of the present invention, and can identify abnormal liquid cooling systems at an early stage, thereby avoiding possible safety risks of subsequent batteries.

[0059] In addition to the abnormality of the liquid cooling system that can cause abnormal temperature of the liquid outlet after the first time period, the present technical solution also takes into account other phenomena that may be caused by abnormality of the liquid cooling system. For example, the temperature of the liquid outlet may fluctuate during the first time period due to the specific blockage of the coolant. Therefore, the fluctuation of the temperature of the liquid outlet can also be used as a detection target and judgment basis. For similar reasons, during the first time period, the temperature of the liquid outlet may have increased significantly due to the blockage. At this time, it can also be considered that the temperature of the liquid outlet is abnormal and the liquid cooling system can be determined to be abnormal. Those skilled in the art can determine the value or value range of the fluctuation threshold through experiments or experience, and this article does not specifically limit it.

[0060] It is also feasible that before determining that the liquid cooling system is abnormal, the method further includes:

[0061] S3: in response to the abnormal temperature of the liquid outlet, obtaining the current temperature of the liquid inlet;

[0062] S4: In response to the difference between the liquid outlet temperature and the current liquid inlet temperature being greater than or equal to the temperature difference ΔT 异常 , it is determined that the liquid cooling system is abnormal.

[0063] It can be seen that compared with the initial technical solution, this method also collects the inlet temperature of the coolant and obtains the temperature difference ΔT between the inlet temperature and the outlet temperature by calculation, for example. 异常, that is, the technical solution uses the temperature difference as a comparison benchmark. Accordingly, it should be known that in the actual detection process, the inlet temperature and outlet temperature of the coolant are collected under the same or similar conditions and the temperature difference between the two is obtained, and compared with the temperature difference ΔT 异常 Compare, and according to the comparison result, it can be determined whether the detected power battery liquid cooling system is abnormal. It should be noted that the reason for additionally considering the liquid inlet temperature here is that it can be considered whether there is a problem with the liquid inlet temperature. For example, when the refrigerant is insufficient, the liquid inlet temperature changes, and the heat exchange is insufficient, which will also cause the temperature difference between the liquid inlet and the liquid outlet to change, and can be detected as abnormal in the above manner. Therefore, the relevant data of the abnormal liquid cooling system can be analyzed. For example, the liquid inlet temperature can be observed to determine whether the abnormal cause is the mechanical deformation of the battery cell itself or somewhere else. That is, the technical solution not only provides another way to detect abnormalities in the liquid cooling system, but also can provide certain guidance for finding the cause of the abnormality. Among them, the temperature difference ΔT 异常 It can be determined based on the power battery with an abnormal liquid cooling system.

[0064] For temperature T 2异常 The specific determination method is, for example, obtaining multiple abnormal liquid outlet temperatures of at least one power battery with an abnormal liquid cooling system; calculating the average value of the multiple abnormal liquid outlet temperatures, and using the average value as the temperature T 2异常 .

[0065] It should be noted that the at least one power battery with abnormal liquid cooling system and the corresponding multiple abnormal liquid outlet temperatures referred to in the technical solution may cover a variety of situations. For example, it may refer to the average value obtained from the liquid outlet temperatures of multiple power batteries with abnormal liquid cooling systems, or the average value obtained from the abnormal liquid outlet temperatures of the same power battery with abnormal liquid cooling system measured in different time periods, and the average value is used as the temperature T 2异常 In addition, those skilled in the art should also know that other methods can be used to obtain such a temperature, such as weighted average, or assigning different weights according to the different degrees of damage to each liquid cooling system.

[0066] In some embodiments of the present disclosure, after determining that the liquid cooling system is abnormal, the method further includes:

[0067] S5: Sending an alarm prompt to the cloud, so that the cloud determines again whether the liquid cooling system is abnormal based on the alarm prompt.

[0068] Through the above technical solutions, it can be known that by sending a reminder to the cloud, the cloud can take some measures: such as troubleshooting abnormal problems, or restricting the operation of the vehicle, etc. Therefore, through the cloud alarm prompt, relevant personnel can make a second judgment or second confirmation of the current liquid cooling system. After two or more confirmations, it can be determined that the liquid cooling system is abnormal, thereby improving the accuracy and reliability of the judgment result. In this process, if the cloud needs to use the judgment reference parameters, such as T 2异常 , ΔT 异常 If the parameters have been updated, a second judgment can be made based on the latest parameters, thereby ensuring the timeliness of the detection or judgment method. In addition, the alarm signal or alarm prompt issued can be presented in a variety of forms, including but not limited to risk prompts in the form of sound or text or images in the interactive interface. In addition, an alarm prompt can also be issued on the vehicle side to remind the user to repair the vehicle.

[0069] It is also feasible to select a power battery with a normal liquid cooling system, make the battery cell temperature reach temperature T0, and make the inlet temperature of the coolant be temperature T1, and after the first period of time, the outlet temperature of the coolant is T2. 2正常 Therefore, in the actual detection process, by comparing the actual liquid outlet temperature with the previously obtained liquid outlet temperature T 2异常 and T 2正常 By comparison, it is possible to determine whether there is any abnormality in the liquid cooling system of the power battery being tested.

[0070] It should be understood that the comparison method mentioned in this article is not limited to the comparison method of whether the compared objects are equal, but can also include the comparison method after the compared objects undergo certain mathematical operations. For example, in this example, the current outlet temperature of the detected coolant can be compared with the outlet temperature T 2异常 With T 2正常 If the average value of T exceeds the average value, it is considered that the power battery liquid cooling system is abnormal. The reason for considering the power battery with a normal liquid cooling system is that this is equivalent to a grayscale test. In other words, if there is a problem in other links other than the mechanical deformation of the liquid cooling system, such as the failure of the sensor of the liquid cooling pipe, the coolant of the whole vehicle, etc., due to the above method of comparing T 2异常 With T 2正常 The difference is equivalent to offsetting the impact of the aforementioned problems, thereby filtering out interference items so as to focus on whether mechanical deformation occurs in the power battery liquid cooling system itself.

[0071] In addition, the comparison after calculation (such as the above comparison with the average value) is characterized in that it can detect liquid cooling systems with lower deformation compared to the abnormal liquid cooling system machinery selected in the calibration method at that time, so it can screen out more liquid cooling systems than the abnormal liquid cooling systems selected in the calibration method, thereby improving the screening strength and thus improving safety. Of course, those skilled in the art can adjust the comparison method according to actual requirements and needs, or even simply compare with the abnormal liquid outlet temperature.

[0072] In addition, it can be seen that the coolant outlet temperature T 2异常 It is obtained after the first period of time has continued. It should be known that the purpose of continuing for a period of time is to allow the coolant to have sufficient time to exchange heat with the battery cell, and the outlet temperature of the coolant can be significantly different from the inlet temperature, so as to clearly distinguish the two and obtain a measurement result that is more resistant to small fluctuations and disturbances. It should also be known that the longer the first time is, the better. If the time is too long, on the one hand, it will affect the implementation efficiency of the method. On the other hand, the difference between the outlet temperature of the abnormal liquid cooling system and the normal liquid cooling system may change from larger to smaller (this will be in Figure 4 ). For example, the first time is selected in the range of 5 to 15 minutes, for example, 10 minutes. Those skilled in the art know that the selection of the first time can be determined according to the actual vehicle model and the related parts used, or the relationship between the first time and the above-mentioned liquid outlet temperature difference can be determined by conducting experiments, thereby determining a better selection range of the first time.

[0073] Similarly, a power battery with a normal liquid cooling system can be selected, and the cell temperature can be set to T0, and the inlet temperature of the coolant can be set to T1. After the first period of time, the outlet temperature of the coolant can be set to T1. 2正常 , and the temperature difference ΔT between the inlet temperature and the outlet temperature of the coolant is also obtained 正常 Thus, the technical effect described above can be achieved by considering the inlet temperature and the temperature difference between the inlet temperature and the outlet temperature, as well as introducing the relevant values ​​of the normal liquid cooling system. Similarly, those skilled in the art can adjust the comparison method according to actual requirements and needs, or even simply compare the temperature difference with the abnormal one.

[0074] The temperature difference between temperature T0 and temperature T1 can be selected to be greater than 20 degrees Celsius to improve accuracy and coolant heat exchange rate, so as to obtain a more obvious heat exchange effect and the resulting coolant outlet temperature. Those skilled in the art know that other suitable temperature differences can be determined by adjusting the temperature difference between temperature T0 and temperature T1 and observing the relative change of the coolant outlet temperature through experiments.

[0075] It is also understood that if multiple physical quantities are involved at the same time, not only can the magnitude be directly compared as described above, but also the corresponding judgment result can be output by performing certain calculations on these physical quantities and then comparing them during the judgment process. As an example, before determining that the liquid cooling system is abnormal, it also includes: S6: In response to the temperature difference between the liquid outlet temperature and the liquid inlet temperature being equal to or greater than the temperature difference ΔT 异常 and temperature difference ΔT 正常 The average value of is used to determine that the liquid cooling system is abnormal.

[0076] It can be seen that in the above technical solution, the temperature difference between the outlet temperature and the inlet temperature of the coolant in the normal and abnormal power battery liquid cooling system is used as a reference for judgment, and the physical quantity used for comparison in the judgment is the temperature difference ΔT 异常 and temperature difference ΔT 正常 The average value. As mentioned before, by considering the average value, it is possible to detect a liquid cooling system with a lower degree of deformation compared to the selected abnormal liquid cooling system, so that a liquid cooling system with a larger number of selected abnormal liquid cooling systems can be screened, thereby improving the screening intensity and thus improving safety. Of course, those skilled in the art can adjust the comparison method or calculation method according to actual requirements and needs, or even simply compare the temperature difference between the abnormal liquid outlet temperature and the liquid inlet temperature. In addition, step S6 can be executed by the battery management system BMS.

[0077] Regarding the application scenarios of the detection method, in some embodiments, the detection method is executed when the fluctuation of the incoming current or the power supply current of the vehicle power battery is less than the fluctuation threshold within a certain period of time. This technical solution takes into account that the current stability of the incoming current or the power supply current of the vehicle power battery is a prerequisite for executing this detection method. This is because if the current is unstable, the current fluctuation may be relatively large, and then a large temperature rise fluctuation will occur, which will affect the temperature measurement and judgment of the detection method. If the current is stable, the temperature rise is stable and predictable. Among them, the incoming current includes the current during charging, and the power supply current includes the output current.

[0078] Specifically, the detection method can be performed when the vehicle is in the fast charging process. It should be understood that vehicle fast charging is a common term in this field, so it is clear. It can be divided according to the charging time, or according to the charging rate, charging power, and so on. For example, charging with high-power direct current, the charging power is generally more than 40kw for fast charging; charging with low-power alternating current, the charging power is generally 3kw or 7kw for slow charging. The reason for adopting the fast charging process is that, on the one hand, the fast charging process is the most common way to replenish energy for electric vehicles, so that the verification coverage of this method is guaranteed, and it has good versatility and universality; on the other hand, the fast charging process is implemented with high efficiency, and the battery cell temperature can be increased relatively quickly and reach the preset threshold or threshold range. In addition, similar to the above, the current is stable and the temperature rise is stable during fast charging, while in other working conditions, the temperature rise fluctuation may not be easy to predict.

[0079] To improve the reliability of the result of the detection method, it is also feasible to monitor the target battery cell temperature and the liquid inlet temperature of the liquid cooling system during the first time period;

[0080] In response to a change in any one of the target battery cell temperature and the liquid inlet temperature of the liquid cooling system exceeding a change threshold, the detection method is re-executed.

[0081] According to the technical solution, if the inlet temperature of the power battery liquid cooling system or the target cell temperature changes significantly or the change exceeds the threshold, the detection method is re-executed. At this time, abnormality troubleshooting can be considered, especially checking whether there is a fault on the vehicle end. Possible reasons include other systems of the vehicle, such as vehicle refrigeration failure, and corresponding alarm information can be sent to the user to avoid any potential impact on the coolant outlet temperature due to excessive changes in the cell temperature or the coolant inlet temperature.

[0082] In order to improve the execution efficiency of the method, the temperature difference can be preset in theory in advance, and then the actual temperature difference can be determined through experiments or the execution of method steps. In this way, the theoretical value can be used as a reference in some cases when it is not convenient to actually test the temperature difference. The theoretical calculation formula of the temperature difference ΔT is:

[0083] ΔT=K*A*(T cell -T coolant ) / c*m.

[0084] Where K is the thermal conductivity of the liquid cooling system, A is the contact area between the liquid cooling system and the battery, and T cell is the average cell temperature, T coolantis the average temperature of the coolant, c is the specific heat capacity of the coolant, and m is the mass flow rate of the coolant per unit time. Alternatively, the formula can be used as a reference to determine whether the temperature difference obtained in the actual method execution is a reasonable temperature difference.

[0085] refer to Figure 4 , which shows a graph of the difference in coolant outlet temperature between a normal battery and a battery with a damaged liquid cooling system at the same cell temperature and liquid inlet temperature during fast charging. The graph shows a curve C1 of the average cell temperature when the liquid cooling system of the power battery is normal, a curve C2 of the average cell temperature when the liquid cooling system is abnormal, a charge state curve C3 of the battery management system, a liquid outlet temperature curve C4 when the liquid cooling system is abnormal, a liquid outlet temperature curve C5 when the liquid cooling system is normal, and a liquid inlet temperature curve C6. The left vertical axis is marked in degrees Celsius, and the right vertical axis is marked in percentage of the charge state.

[0086] In particular, the figure exemplarily shows how the normal and abnormal liquid outlet temperatures of the power battery liquid cooling system change over time. It can be seen that the temperature difference between the normal and abnormal liquid outlet temperatures is larger and more obvious in the front part of the figure (for example, the first quarter), and the temperature difference gradually approaches each other afterwards, and the difference between the two becomes less obvious. Therefore, this phenomenon can also be used as a reference for how to take the value at the first time, that is, those skilled in the art know that the selection of the first time can be carried out within a larger range of temperature differences, so that the results are more significant and accurate. It goes without saying that Figure 4 The trend of each curve is related to the vehicle model. Those skilled in the art can determine the trend of the curve through experiments or the above-mentioned theoretical formula, and then determine the value range of parameters such as the first time.

[0087] refer to Figure 5 , which shows a schematic structural diagram of a detection device for a power battery liquid cooling system according to the present invention.

[0088] Among them, since the specific shape and connection method of each component are not the subject of the present invention, for the sake of clarity and simplicity, all these components are schematically given in the form of structural modules, and those skilled in the art can choose appropriate module shapes and connection methods, etc. under the guidance of the structural diagram. In addition, the structural diagram given is an embodiment of the present invention, and those skilled in the art can make various modifications without departing from the spirit of the present invention after referring to the diagram, and these modifications should also be within the scope of protection of the present invention.

[0089] The detection device 100 comprises:

[0090] A collection module 1, wherein the collection module 1 collects the temperature of the liquid outlet of the liquid cooling system when the target battery cell temperature is equal to temperature T0 and the temperature of the liquid inlet of the liquid cooling system is equal to temperature T1, wherein temperature T0 is less than the battery cell temperature when the liquid cooling system is turned on;

[0091] The judgment module 2 judges whether the temperature of the liquid outlet is abnormal within a first time period, and if so, determines that the liquid cooling system is abnormal.

[0092] Regarding the specific implementation methods of the detection device and the technical effects that can be achieved, please refer to the relevant content of the detection method above for interpretation, and no further details will be given here.

[0093] Correspondingly, in some embodiments, the determination module 2 detects whether the current liquid outlet temperature is abnormal, including one or more of the following situations:

[0094] Check whether the liquid outlet temperature after the first time period is equal to or greater than the temperature T 2异常 , if yes, then it is determined that the temperature of the liquid outlet is abnormal;

[0095] Detecting whether the fluctuation of the temperature of the liquid outlet in the first time period is equal to or greater than a fluctuation threshold, and if so, determining that the temperature of the liquid outlet is abnormal;

[0096] Detect whether the liquid outlet temperature in the first time period is equal to or greater than the temperature T 2异常 , if yes, then it is determined that the temperature of the liquid outlet is abnormal;

[0097] Among them, the temperature T 2异常 It can be determined based on the power battery with abnormal liquid cooling system.

[0098] In some embodiments, before the judgment module 2 determines that the liquid cooling system is abnormal, the acquisition module 1 obtains the current liquid inlet temperature in response to the abnormal liquid outlet temperature; the judgment module 2 obtains the current liquid inlet temperature in response to the difference between the liquid outlet temperature and the current liquid inlet temperature being greater than or equal to the temperature difference ΔT 异常 , determining that the liquid cooling system is abnormal;

[0099] Among them, the temperature difference ΔT 异常 It can be determined based on the power battery with abnormal liquid cooling system.

[0100] In some embodiments, the detection device 100 further includes a calculation module 3, wherein the acquisition module 1 obtains the abnormal temperatures of multiple liquid outlets of at least one power battery with an abnormal liquid cooling system, and the calculation module 3 calculates the average value of the abnormal temperatures of the multiple liquid outlets, and uses the average value as the temperature T 2异常 .

[0101] In some embodiments, the detection device 100 also includes an output module 4. After the judgment module 2 determines that the liquid cooling system is abnormal, the output module 4 sends an alarm prompt to the cloud, so that the cloud can determine again whether the liquid cooling system is abnormal based on the alarm prompt.

[0102] In some embodiments, before the judgment module 2 determines that the liquid cooling system is abnormal, the judgment module 2 responds to the temperature difference between the liquid outlet temperature and the liquid inlet temperature being equal to or greater than the temperature difference ΔT 异常 and temperature difference ΔT 正常 The average value of the temperature difference ΔT determines that the liquid cooling system is abnormal; wherein the temperature difference ΔT 正常 Determined based on the power battery with normal liquid cooling system.

[0103] In some embodiments, the temperature difference between temperature T0 and temperature T1 is greater than 20 degrees Celsius. The target cell temperature is the highest cell temperature among the cells of the power battery.

[0104] In some embodiments, the detection device 100 also includes a monitoring module 5, which monitors the target battery cell temperature and the liquid inlet temperature of the liquid cooling system within a first time period. If the change amplitude of either the target battery cell temperature or the liquid inlet temperature of the liquid cooling system exceeds a change threshold, the acquisition module 1 and the judgment module 2 re-collect and judge respectively.

[0105] In some embodiments, the acquisition module 1 also acquires the inlet current or the supply current of the vehicle power battery, and the judgment module 2 further judges whether the fluctuation of the inlet current or the supply current is less than the fluctuation threshold within a certain period of time.

[0106] In some embodiments, the determination module 2 further determines whether the vehicle is in a fast charging process.

[0107] It should be mentioned that the detection device 100 can be undertaken by the vehicle main control, integrated into the main control or controlled by the main control, and the battery management system BMS executes the detection method. Of course, the pressure on the vehicle side can be shared through the participation of the cloud, especially the calculation pressure on the vehicle side will be much smaller. For example, the parameters are set and updated in the cloud, and instructions are sent from the cloud to the battery management system to modify the values ​​of relevant parameters, such as temperature T0, temperature T1, etc.

[0108] According to two other aspects of the present invention, the present invention relates respectively to a computer-readable storage medium on which a computer program is stored, wherein the computer program implements any one of the above-mentioned detection methods when executed by a processor; and to a computer device, wherein the computer device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements any one of the above-mentioned detection methods when executing the computer program.

[0109] Similarly, it can be understood that the computer-readable storage medium has all the technical effects of the aforementioned detection method. The computer device has all the technical effects of the aforementioned detection method, which will not be repeated here. In addition, the computer device may include a control device formed by various electronic devices. For example, the computer device may be a main control on a vehicle or a battery management system BMS in a battery pack.

[0110] It is understood by those skilled in the art that the present invention implements all or part of the processes in its detection method, which can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a computer-readable storage medium. When the computer program is executed by the processor, the steps of each of the above-mentioned method embodiments can be implemented. Among them, the computer program includes computer program code, and it can be understood that the program code includes but is not limited to the program code for executing the above-mentioned detection method. For the convenience of explanation, only the part related to the present invention is shown. The computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable storage medium may include: any entity or device, medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory, random access memory, electric carrier signal, telecommunication signal and software distribution medium that can carry the computer program code. It should be noted that the content contained in the computer-readable storage medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable storage medium does not include electric carrier signals and telecommunication signals.

[0111] The relevant user personal information that may be involved in the various embodiments of this application is strictly in accordance with the requirements of laws and regulations, following the principles of legality, legitimacy and necessity, based on the reasonable purposes of business scenarios, to process the personal information that users actively provide during the use of products / services or generated due to the use of products / services, as well as the personal information obtained with the user's authorization.

[0112] The user personal information processed by the applicant will vary depending on the specific product / service scenario, and shall be based on the specific scenario in which the user uses the product / service, which may involve the user's account information, device information, driving information, vehicle information or other related information. The applicant will treat the user's personal information and its processing with a high degree of diligence.

[0113] The Applicant attaches great importance to the security of user personal information and has adopted reasonable and feasible security protection measures that comply with industry standards to protect user information and prevent personal information from being accessed, disclosed, used, modified, damaged or lost without authorization.

[0114] It should be understood that all the above preferred embodiments are illustrative rather than restrictive, and various modifications or variations made by those skilled in the art to the specific embodiments described above under the concept of the present invention should be within the legal protection scope of the present invention.

Claims

1. A method for detecting a power battery liquid cooling system, characterized in that: The detection method comprises: When the target battery cell temperature is equal to temperature T0 and the liquid inlet temperature of the liquid cooling system is greater than or equal to temperature T1, collecting the liquid outlet temperature of the liquid cooling system, wherein temperature T0 is less than the battery cell temperature when the liquid cooling system is turned on; In the first time period, it is determined whether the temperature of the liquid outlet is abnormal, and if so, it is determined that the liquid cooling system is abnormal.

2. The detection method according to claim 1, characterized in that: Detect whether the current liquid outlet temperature is abnormal, including at least one of the following situations: In response to detecting that the temperature of the liquid outlet after the first time period is equal to or greater than the temperature T 2异常 , determining that the temperature of the liquid outlet is abnormal; In response to detecting that a fluctuation of the temperature of the liquid outlet within the first time period is equal to or greater than a fluctuation threshold, determining that the temperature of the liquid outlet is abnormal; In response to detecting that the temperature of the liquid outlet during the first time period is equal to or greater than the temperature T 2异常 , determining that the temperature of the liquid outlet is abnormal.

3. The detection method according to claim 1 or 2, characterized in that: Before determining that the liquid cooling system is abnormal, the method further includes: In response to the abnormal temperature of the liquid outlet, obtaining the current temperature of the liquid inlet; In response to the difference between the liquid outlet temperature and the current liquid inlet temperature being greater than or equal to the temperature difference ΔT 异常 , it is determined that the liquid cooling system is abnormal.

4. The detection method according to claim 2, characterized in that: Temperature T 2异常 Determined based on the following method: Obtaining abnormal temperatures of multiple liquid outlets of at least one power battery having an abnormal liquid cooling system; Calculate the average value of abnormal temperatures of multiple liquid outlets and use the average value as the temperature T 2异常 .

5. The detection method according to claim 1, characterized in that: After determining that the liquid cooling system is abnormal, the method further includes: An alarm is sent to the cloud, so that the cloud determines again whether the liquid cooling system is abnormal based on the alarm.

6. The detection method according to claim 3, characterized in that: Before determining that the liquid cooling system is abnormal, the method further includes: In response to the temperature difference between the liquid outlet temperature and the liquid inlet temperature being equal to or greater than the temperature difference ΔT 异常 and temperature difference ΔT 正常 The average value of is used to determine that the liquid cooling system is abnormal.

7. The detection method according to claim 1 or 2, characterized in that: The detection method is executed when the fluctuation of the inlet current or the supply current of the vehicle power battery is less than the fluctuation threshold within a certain period of time.

8. The detection method according to claim 7, characterized in that: The detection method is performed when the vehicle is in a fast charging process.

9. The detection method according to claim 1 or 2, characterized in that: The temperature difference between temperature T0 and temperature T1 is greater than 20 degrees Celsius.

10. The detection method according to claim 1 or 2, characterized in that: The target battery cell temperature is selected as the highest battery cell temperature among the battery cells of the power battery.

11. The detection method according to claim 1 or 2, characterized in that: During the first time period, the target battery cell temperature and the liquid inlet temperature of the liquid cooling system are monitored; In response to a change in any one of the target battery cell temperature and the liquid inlet temperature of the liquid cooling system exceeding a change threshold, the detection method is re-executed.

12. A detection device (100) for a power battery liquid cooling system, characterized in that: The detection device (100) comprises: A collection module (1), wherein the collection module (1) collects the temperature of the liquid outlet of the liquid cooling system when the target battery cell temperature is equal to temperature T0 and the temperature of the liquid inlet of the liquid cooling system is equal to temperature T1, wherein temperature T0 is less than the battery cell temperature when the liquid cooling system is turned on; A judgment module (2), wherein the judgment module (2) judges whether the temperature of the liquid outlet is abnormal within a first time period, and if so, determines that the liquid cooling system is abnormal.

13. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the detection method according to any one of claims 1 to 11 is implemented.

14. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the detection method according to any one of claims 1 to 11 is implemented.

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