A performance testing method and system of a direct-cooling battery cluster thermal management device

Abstract

The present application relates to the technical field of energy storage thermal management, in particular to a performance testing method and system of a direct cooling battery cluster thermal management device, comprising: based on thermal simulation test of single battery cell, determining the instantaneous heat generation power and the equivalent target temperature of the battery pack; calculating the battery heat capacity correction value; setting an electric-thermal conversion component on the direct cooling plate; determining the feedback correction value of the electric-thermal conversion component; based on the instantaneous heat generation power of the battery pack, the battery heat capacity correction value and the feedback correction value of the electric-thermal conversion component, calculating the output power of the electric-thermal conversion component, and dynamically adjusting the actual output power of the electric-thermal conversion component; collecting the refrigerant temperature of the inlet and outlet of the direct cooling plate, constructing the coupling performance index, and evaluating the refrigerant distribution uniformity of the device. Through the test method and system, the dynamic heat flow generated at the heat exchange interface during the operation of the battery pack can be accurately simulated, and the refrigerant distribution uniformity of the direct cooling battery cluster thermal management device can be accurately evaluated.

Description

Technical Field

[0001] This invention relates to the field of energy storage thermal management technology, and in particular to a performance testing method and system for a direct-cooling battery cluster thermal management device. Background Technology

[0002] With the rapid iteration of the new energy industry, battery clusters, as the core energy carriers, directly determine the reliability of the entire system through their operational safety and stability. Direct-cooled battery cluster thermal management devices, which directly exchange heat with individual battery cells, have become a key technology for solving the heat dissipation problem of high-energy-density battery clusters. However, the performance of direct-cooled battery cluster thermal management devices is affected by the coupling of multiple parameters such as refrigerant flow rate, evaporation pressure, battery heat load, and ambient temperature. Their core indicators, such as temperature regulation accuracy, temperature uniformity, and cooling efficiency, are directly related to the battery's cycle life and safety performance. Therefore, systematic and accurate performance testing of direct-cooled battery cluster thermal management devices is particularly important.

[0003] In the prior art, a Chinese invention patent document with publication number CN120908692A and publication date of November 7, 2025 has been proposed. The technical solution disclosed in this patent document is as follows: a test method and system for thermal management of a refrigerant phase change cooling power battery. The method involves obtaining the actual cooling capacity during the test, determining the superheat setpoint of the test system using the expression corresponding to the actual cooling capacity and the pre-obtained minimum stable superheat, determining the control stability of the test system using the current superheat and the superheat setpoint, and then adjusting the opening of the electronic expansion valve based on the control stability to achieve the adjustment of the superheat in the test system.

[0004] The aforementioned technical solution focuses on dynamically determining the optimal superheat setpoint during testing to ensure stable system operation. This solution assumes that the refrigerant piping system, liquid distribution structure, and direct cooling plate itself are reasonably designed. However, in actual product development, core issues such as uneven refrigerant distribution and poor battery temperature consistency often stem from design flaws in the piping and direct cooling plate subsystems themselves. For energy storage battery cluster thermal management devices, there is a lack of a dedicated testing method and system capable of efficiently and accurately verifying the piping design and direct cooling plate performance of direct-cooled battery clusters.

[0005] In the prior art, a Chinese invention patent document with publication number CN115014830A and publication date of September 6, 2022, is disclosed. The technical solution disclosed in this patent document is as follows: a bench test method and apparatus for a refrigerant direct cooling system. The method includes: detecting whether the first dry-bulb and wet-bulb tests at the outdoor wind tunnel and the second dry-bulb and wet-bulb tests at the indoor wind tunnel are normal; wherein, a condenser is also installed at the outdoor wind tunnel and an air conditioner is also installed at the indoor wind tunnel, and the condenser, air conditioner and battery are connected by pipelines; if so, the indoor ambient temperature is adjusted to a first target temperature, the outdoor ambient temperature is adjusted to a second target temperature, and the battery temperature is adjusted to a third target temperature; the refrigerant direct cooling system is started, and the outlet superheat of the air conditioner evaporator and the battery evaporator is stabilized at a preset temperature; the thermocouple temperature and pressure values ​​of the battery, air conditioner and pipelines are recorded.

[0006] The aforementioned technical solutions are limited to vehicle thermal management and cannot be directly applied to direct cooling systems for energy storage batteries that face multi-level, large-scale parallel challenges. In particular, for energy storage battery clusters, temperature uniformity is not only affected by system-level refrigerant distribution but also fundamentally depends on the uniformity of refrigerant distribution among numerous parallel direct cooling plates on each battery rack. This technical solution only addresses the refrigerant distribution and coordinated control between two evaporators, failing to delve into the underlying hardware issue of refrigerant distribution uniformity among multiple parallel direct cooling plates within the energy storage battery cooling unit.

[0007] In the prior art, a Chinese invention patent document with publication number CN121114641A and publication date of December 12, 2025, was proposed. The technical solution disclosed in this patent document is as follows: an energy storage thermal management test platform and method, which sets the initial ambient temperature and coolant flow rate through a full-size energy storage tank thermal environment simulation system and a liquid cooling circulation system, and outputs multi-region environmental parameters; generates simulated thermal load based on environmental parameters, adjusts the thermal load intensity and verifies the spatial distribution uniformity through the dynamic feedback mechanism of the central controller; under the action of thermal load, uses a multi-level temperature sensor array and a thermal imager to synchronously collect three-dimensional temperature of the battery pack, temperature difference between the inlet and outlet of the coolant and flow rate data, and constructs a spatiotemporal correlation dataset with heat flux density mapping; reconstructs the three-dimensional thermal field distribution based on the dataset using a spatial interpolation algorithm, calculates the temperature rise rate and heat dissipation efficiency ratio, and outputs an evaluation result containing a thermal field uniformity index; and achieves a dual improvement in test efficiency and energy efficiency evaluation accuracy through multi-cycle iterative optimization of ambient temperature and thermal load parameters.

[0008] The aforementioned system-level testing methods have inherent limitations: test preparation is complex and costly, and when test results are unsatisfactory, it is difficult to accurately pinpoint the root cause of the problem to specific subsystems such as the battery pack, coolant circuit, or environmental control system. In particular, for direct-cooling systems, the critical design parameter of refrigerant distribution uniformity cannot be directly and independently observed and quantified in these system-level tests. Furthermore, in this technical solution, the intensity of the simulated heat load on the battery pack is determined based on measured ambient temperature values ​​and heat flux density deviations, which cannot accurately simulate the state of the battery pack during operation.

[0009] In summary, existing performance testing systems and methods still have shortcomings in simulating the heat flow generated at the heat exchange interface during battery pack operation, and their ability to evaluate the refrigerant distribution uniformity of direct-cooled battery cluster thermal management devices also needs to be improved. Summary of the Invention

[0010] To address the aforementioned technical problems, this invention proposes a performance testing method and system for a direct-cooling battery cluster thermal management device. This method can accurately simulate the dynamic heat flow generated at the heat exchange interface during battery pack operation and can accurately assess the refrigerant distribution uniformity of the direct-cooling battery cluster thermal management device before battery compartment integration.

[0011] This invention is achieved by adopting the following technical solution: A performance testing method for a direct-cooled battery cluster thermal management device includes the following steps: Based on thermal simulation tests of individual battery cells, the instantaneous heat generation power and equivalent target temperature of the battery pack are determined. Calculate the battery heat capacity correction value based on the equivalent target temperature of the battery pack and the total heat capacity of the battery pack; An electro-thermal conversion component for simulating battery pack heating is installed on the direct cooling plate of the direct cooling battery cluster thermal management device. After a refrigerant with a set flow rate and state is input into the direct cooling plate, the electro-thermal conversion component is controlled to start heating. The temperature of the electro-thermal conversion component is collected in real time, and the feedback correction value of the electro-thermal conversion component is determined based on the heat capacity of the electro-thermal conversion component. Based on the instantaneous heat generation power of the battery pack, the battery thermal capacity correction value, and the feedback correction value of the electro-thermal conversion component, the output power of the electro-thermal conversion component is calculated, and the actual output power of the electro-thermal conversion component is dynamically adjusted based on the output power. During or after the test, the refrigerant temperature at the inlet and outlet of the direct cooling plate is collected; based on the refrigerant temperature and the temperature of the electro-thermal conversion component, a coupling performance index is constructed. The uniformity of refrigerant distribution in a direct-cooling battery cluster thermal management device is evaluated based on coupling performance indicators.

[0012] Based on thermal simulation experiments of individual battery cells, the instantaneous heat generation power and equivalent target temperature of the battery pack are determined, specifically: Based on thermal simulation experiments of a single battery cell, the transient temperature history of the geometric center point on the bottom surface of the single battery cell was obtained. and the transient integral power of the global volumetric heat source ; The equivalent target temperature of the battery pack is determined as follows: ; The instantaneous heat generation power of the battery pack is determined as follows: ; In the formula, For the first The equivalent target temperature of the battery pack per operating cycle. For the first The instantaneous heat generation power of the battery pack per operating cycle, This refers to the total number of individual battery cells within the battery pack. For the operating cycle.

[0013] The calculation methods for battery thermal capacity correction values ​​include: Equivalent target temperature of the battery pack Perform low-pass filtering to obtain the target temperature change rate. ; Based on the target temperature change rate And the total heat capacity of the battery pack, calculate the battery heat capacity correction value: , , In the formula, For the first Battery thermal capacity correction value for each operating cycle. The total heat capacity of the battery pack. For the quality of a single battery cell, This refers to the specific heat capacity of a single battery cell. This refers to the total number of individual battery cells within the battery pack.

[0014] Equivalent target temperature of the battery pack Low-pass filtering is performed, specifically referring to the filtering of the battery pack's equivalent target temperature. After applying a first-order low-pass filter, the result is Then, the derivative of the filtered data is calculated to determine the target temperature change rate. : , , In the formula, For the operating cycle, For the first The equivalent target temperature after first-order low-pass filtering is used for each operating cycle. For the first The equivalent target temperature after first-order low-pass filtering is used for each operating cycle. These are the filter coefficients. The sampling period.

[0015] The calculation methods for the feedback correction value of the electro-thermal conversion component include: The temperature of the electro-thermal conversion component is collected in real time. Median filtering was performed to obtain the measured temperature change rate. ; Based on measured temperature change rate And the heat capacity of the electro-thermal conversion component, calculate the feedback correction value of the electro-thermal conversion component: , , In the formula, For the first Feedback correction value of the electro-thermal conversion component for each operating cycle. For the heat capacity of the electro-thermal conversion component, For the quality of the electro-thermal conversion components, This refers to the specific heat capacity of the electro-thermal conversion component.

[0016] The temperature of the electro-thermal conversion component is collected in real time. Median filtering specifically refers to the real-time acquisition of the temperature of the electro-thermal conversion component. After applying median filtering, the result is Then, the derivative of the filtered data is calculated to determine the measured rate of temperature change. : , , In the formula, For the operating cycle, For window length, For the first The temperature of the electro-thermal conversion component after median filtering during each operating cycle; For the first The temperature of the electro-thermal conversion component after median filtering after each operating cycle. For the first The temperature of the electro-thermal conversion component during each operating cycle. It is a median operation function; The sampling period.

[0017] The calculation method for the output power of the electro-thermal conversion component is as follows: , , In the formula, For the first The power output per operating cycle This represents the maximum output power of the electro-thermal conversion component. For the first Intermediate calculation power per operating cycle, For the first The instantaneous heat generation power of the battery pack per operating cycle, For the first Battery thermal capacity correction value for each operating cycle. For the first Feedback correction value of the electro-thermal conversion component for each operating cycle. For the operating cycle.

[0018] The direct-cooling battery cluster thermal management device includes The system consists of several parallel branches, each equipped with a direct cooling plate; the coupling performance indicators are as follows: ; In the formula, For the first The coupling performance index of the branch path For the first The average temperature difference between the electro-thermal conversion component and the refrigerant in each branch circuit. for a side road The arithmetic mean; For the first The refrigerant inlet and outlet temperature rise of the branch circuit for a side road The arithmetic mean.

[0019] The method for calculating the average temperature difference between the electro-thermal conversion component and the refrigerant is as follows: , The calculation method for refrigerant inlet and outlet temperature rise is as follows: , In the formula, For the first The average temperature difference between the electro-thermal conversion component and the refrigerant in each branch circuit. For the first The refrigerant inlet and outlet temperature rise of the branch circuit For the first The temperature of the electro-thermal conversion component in each branch, For the first The refrigerant temperature at the inlet of the direct-cooling plate in this branch circuit. For the first The refrigerant temperature at the outlet of the direct cooling plate of the branch circuit.

[0020] The refrigerant distribution uniformity of the direct-cooled battery cluster thermal management device is evaluated, specifically by calculating the coupling performance indices of all branches. Sample standard deviation ; Sample standard deviation The refrigerant distribution of the direct-cooled battery cluster thermal management device is compared with a preset threshold to determine whether the refrigerant distribution is uniform.

[0021] It also includes: comparing the coupling performance index of each branch with the preset range value to identify abnormal branches.

[0022] It also includes: drawing a two-factor diagnostic chart to visually display the status of each branch and identify the causes of abnormality in abnormal branches; the two-factor diagnostic chart is based on... Using the X-axis as the reference, Using the Y-axis, each branch is plotted as a data point (X, Y).

[0023] The causes of anomalies in abnormal branches are identified by comparing the positional relationship between data points (X, Y) and the relative ideal point (1, 1). If the data points of the abnormal branch satisfy X > 1 and Y > 1, then there is a problem with the design of the distributor and pipeline corresponding to the abnormal branch; if the data points of the abnormal branch satisfy X < 1 and Y > 1, then there is a problem with the installation process and interface materials corresponding to the abnormal branch; if the data points of the abnormal branch satisfy X < 1 and Y < 1, then there is an over-diversion problem in the pipeline or distributor corresponding to the abnormal branch; if the data points of the abnormal branch satisfy X > 1 and Y < 1, then there is a problem with the collected temperature data.

[0024] A performance testing system for a direct-cooled battery cluster thermal management device includes a thermal simulation test unit, a refrigerant supply unit, a thermal interaction unit, a data acquisition unit, a control unit, and a data analysis unit. The thermal simulation test unit is used to conduct thermal simulation tests on individual battery cells to obtain the instantaneous heat generation power and equivalent target temperature of the battery pack. The refrigerant supply unit is connected to the direct cooling plate of the direct cooling battery cluster thermal management device and is used to introduce refrigerant into the direct cooling plate. The thermal interaction unit includes a connected electro-thermal conversion component and a programmable DC power supply; the electro-thermal conversion component is mounted on the direct cooling plate and is used to simulate the dynamic heat flow generated at the heat exchange interface during the operation of the battery pack; The data acquisition unit is used to collect the temperature of the electro-thermal conversion component and the refrigerant temperature at the inlet and outlet of the direct cooling plate in real time; The control unit is used to calculate the battery heat capacity correction value based on the equivalent target temperature of the battery pack and the total heat capacity of the battery pack; to determine the feedback correction value of the electro-thermal conversion component based on the temperature of the electro-thermal conversion component collected in real time and in combination with the heat capacity of the electro-thermal conversion component; and to calculate the output power of the electro-thermal conversion component based on the instantaneous heat generation power of the battery pack, the battery heat capacity correction value, and the feedback correction value of the electro-thermal conversion component, and to dynamically adjust the actual output power of the electro-thermal conversion component through a programmable DC power supply. The data analysis unit is used to construct a coupling performance index by collecting the refrigerant temperature at the inlet and outlet of the direct cooling plate and the temperature of the electro-thermal conversion component, and to evaluate the refrigerant distribution uniformity of the direct cooling battery cluster thermal management device based on the coupling performance index.

[0025] The temperature of the electro-thermal conversion component collected in real time is the operating cycle. The arithmetic mean of the data collected by multiple temperature sensors.

[0026] The multiple temperature sensors are respectively arranged at the geometric center of the electro-thermal conversion component and at the center projection of the inlet, outlet and split / merge structure of the direct cooling plate channel.

[0027] It also includes an abnormal branch identification unit; the direct-cooled battery cluster thermal management device includes The system has several parallel branches, each equipped with a direct cooling plate; the abnormal branch identification unit is used to identify abnormal branches based on the comparison of the coupling performance index of each branch with a preset range value.

[0028] It also includes a display unit for drawing a two-factor diagnostic chart to visually display the status of each branch; the two-factor diagnostic chart uses... Using the X-axis as the reference, Using the Y-axis as the plotting axis, each branch is plotted as a data point (X, Y); the cause of the branch anomaly is determined by comparing the positional relationship between the data point (X, Y) and the relative ideal point (1, 1). In the formula, For the first The average temperature difference between the electro-thermal conversion component and the refrigerant in each branch circuit. for a side road The arithmetic mean; For the first The refrigerant inlet and outlet temperature rise of the branch circuit for a side road The arithmetic mean.

[0029] It also includes an environmental simulation unit for simulating ambient temperature and humidity.

[0030] The thermal interaction unit also includes a replaceable thermal interface layer; the thermal interface layer is disposed between the electro-thermal conversion component and the direct cooling plate.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. In the testing method of this invention, the output power of the electro-thermal conversion component is calculated based on the instantaneous heat generation power of the battery pack, the battery thermal capacity correction value, and the feedback correction value of the electro-thermal conversion component. Based on this output power, the actual output power of the electro-thermal conversion component is dynamically adjusted, enabling precise adjustment of the heat generation of the electro-thermal conversion component. This makes it suitable for electrochemical energy storage systems of any voltage level and capacity. Specifically, the method for dynamically adjusting the actual output power of the electro-thermal conversion component includes the following core mechanisms: First, this dynamic adjustment is based on the instantaneous heat generation power of the battery pack determined by thermal simulation experiments, directly reflecting the theoretical heat flow without being smoothed by physical thermal inertia, thus preserving the pure dynamic characteristics of the thermal load. If measured power data is used as the feedforward, some energy has already been converted into internal energy accumulation, and the measured power data itself already carries the battery's thermal inertia response characteristics; if the battery thermal capacity correction value is subsequently added, it will lead to repeated calculations of the battery's thermal inertia, introducing systematic errors.

[0032] Second, the battery thermal capacity correction value is calculated based on the equivalent target temperature of the battery pack determined by thermal simulation experiments. This battery thermal capacity correction value, together with the feedforward basis, constitutes the dynamic description of the electro-thermal conversion component in the time domain. Specifically, the equivalent target temperature of the battery pack originates from a simulation model that includes the internal thermal resistance characteristics of the battery pack, and its response already reflects the smoothing and hysteresis effects of thermal resistance on temperature response. Therefore, the battery thermal capacity correction value derived from this equivalent target temperature has already incorporated the time-domain influence of thermal resistance in dynamic changes, and a separate independent thermal resistance correction closed-loop term is no longer introduced into the control loop, avoiding repeated compensation for the same thermal resistance effect.

[0033] Third, the feedback correction value for the electro-thermal conversion component is obtained based on the response deviation caused by its own heat capacity. During dynamic heating, the electro-thermal conversion component, as a heat source, retains some sensible heat, resulting in the actual power transferred to the heat dissipation interface being less than the power commanded by the electrical command. Therefore, this invention monitors the temperature of the electro-thermal conversion component in real time and calculates its feedback correction power, dynamically correcting this portion of energy in the control command. This eliminates the superimposed interference of the electro-thermal conversion component's heat capacity on the heat source simulation, achieving feedback correction for the response deviation caused by the electro-thermal conversion component's own heat capacity.

[0034] By modifying the battery thermal capacity and electro-thermal conversion components as described above, the thermal mass difference between the simulated heat source and the real battery cell is eliminated, enabling the lightweight electro-thermal conversion components to reproduce the real heat at the heat exchange interface of a large inertia battery pack.

[0035] Furthermore, the temperature rise process of a real battery pack exhibits significant thermal lag. The electro-thermal conversion component, being lighter and having a smaller heat capacity than a real battery pack, would experience an instantaneous temperature rise if directly heated to the simulated power, failing to simulate the temperature rise curve of a real battery pack. Therefore, this invention introduces a battery heat capacity correction value to eliminate the leading effect of the temperature rise curve. It also corrects for the sensible heat retained by the electro-thermal conversion component itself through feedback correction values, ensuring that the energy delivered by the power source accurately serves the simulation of the battery's heat generation behavior at the heat exchange interface.

[0036] Therefore, the testing method of this invention uses an electro-thermal conversion component that can accurately simulate the heating of the battery pack to replace the expensive real battery pack for thermal management performance testing in existing direct-cooled battery cluster thermal management devices. This eliminates the thermal runaway safety risk brought about by high-voltage battery field testing, and also eliminates the need to wait for peripheral systems such as the battery management system (BMS) and cabin structure to be completed, allowing for the verification of piping designs in a laboratory environment. This testing system can significantly advance the performance verification node from after product integration to the module design stage, significantly shortening the development cycle and reducing later rectification costs.

[0037] Due to the small diameter and complex internal two-phase flow of directly cooled battery clusters, existing technologies lack low-cost and easy-to-install two-phase flow testing methods, making it impossible to directly determine the flow distribution of each branch within the cluster based on flow data. Therefore, this invention proposes a quantitative evaluation method for refrigerant distribution uniformity based on temperature data streams. Without relying on flow meters, it constructs a coupled performance index using only the refrigerant temperature at the inlet and outlet of the direct-cooling plate and the temperature of the electro-thermal conversion component. The value of this coupled performance index directly quantifies the degree of matching between heat transfer capacity and refrigerant flow state, enabling accurate evaluation of the refrigerant distribution uniformity of the direct-cooled battery cluster thermal management device. This achieves early, direct, and quantitative diagnosis of the underlying hardware design defect of "uneven refrigerant distribution" in the direct-cooled battery cluster thermal management device.

[0038] 2. This invention uses a first-order low-pass filter to measure the equivalent target temperature of the battery pack, and then performs derivative processing on the filtered data, which can avoid high-frequency noise in the simulation data from direct numerical differentiation amplification.

[0039] 3. This invention performs median filtering on the real-time acquired temperature of the electro-thermal conversion component, effectively suppressing the influence of random pulse interference and electromagnetic noise during sensor sampling on the closed-loop feedback. By using a sliding window to take the median, outliers deviating from the physical temperature change gradient are eliminated, thereby ensuring the smoothness of the measured temperature change rate in subsequent differential calculations and preventing high-frequency oscillations.

[0040] 4. The coupling performance index constructed by this invention does not require direct measurement of difficult-to-obtain flow rate or dryness. It can convert the complex "temperature field" and "flow field" anomalies in the system into easily comparable numerical scales using only temperature data, thereby evaluating the uniformity performance of different parallel branches and the entire battery cluster in the time and spatial domains.

[0041] 5. This invention uses coupling performance indicators This method enables rapid quantitative screening, accurately identifies abnormal branches, and utilizes a two-factor diagnostic chart to achieve intuitive and in-depth fault mode separation, forming a complete performance evaluation and diagnostic system from the overall to the local, from the phenomenon to the root cause. Through this method, the specific branch with abnormal flow can be precisely located, fundamentally solving the problem of difficult root cause localization in system-level testing of directly cooled battery cluster thermal management devices.

[0042] 6. This testing system can not only accurately simulate the real heat flow of the battery pack at the heat exchange interface, but also quantify the degree of matching between heat exchange capacity and refrigerant flow state by only requiring the refrigerant temperature at the inlet and outlet of the direct cooling plate and the temperature of the electro-thermal conversion component, thus realizing the overall evaluation of the refrigerant distribution uniformity of the direct cooling battery cluster thermal management device.

[0043] 7. Based on thermodynamic characteristics, the present invention rationally arranges temperature sensors, focusing on covering key areas such as the branching and merging points that determine the flow distribution density and local heat transfer intensity. The average temperature obtained by the sampling is more thermodynamically representative than that obtained by equally spaced points.

[0044] 8. This invention focuses on "ambient temperature and humidity simulation" and "battery pack self-heating simulation". By providing the necessary environmental stress through the environmental simulation unit, the complexity and cost of the system are significantly reduced while ensuring the effectiveness of the test.

[0045] 9. The present invention uses a replaceable thermal interface layer, which can be adapted to the interface of different thermally conductive materials (thermal conductive silicone, phase change materials) to match the diverse thermal interface solutions in actual products. Attached Figure Description

[0046] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments, wherein: Figure 1 This is a flowchart illustrating the testing method in this invention; Figure 2 This is a schematic diagram comparing the actual dynamic heat exchange power of the system with the power of each method. Detailed Implementation

[0047] Example 1 As a basic embodiment of the present invention, the present invention includes a performance testing method for a direct-cooling battery cluster thermal management device, comprising the following steps: Based on thermal simulation tests of individual battery cells, the instantaneous heat generation power and equivalent target temperature of the battery pack are determined.

[0048] The battery heat capacity correction value is calculated based on the equivalent target temperature of the battery pack and the total heat capacity of the battery pack.

[0049] An electro-thermal conversion component for simulating battery pack heating is installed on the direct cooling plate of the direct cooling battery cluster thermal management device. After a set flow rate and state of refrigerant are stably input into the direct cooling plate, the electro-thermal conversion component is controlled to start heating.

[0050] The temperature of the electro-thermal conversion component is collected in real time, and the feedback correction value of the electro-thermal conversion component is determined based on the heat capacity of the electro-thermal conversion component.

[0051] Based on the instantaneous heat generation power of the battery pack, the battery thermal capacity correction value, and the feedback correction value of the electro-thermal conversion component, the output power of the electro-thermal conversion component is calculated, and the actual output power of the electro-thermal conversion component is dynamically adjusted based on the output power.

[0052] During or after the test, the refrigerant temperature at the inlet and outlet of the direct cooling plate is collected; based on the refrigerant temperature and the temperature of the electro-thermal conversion component, a coupling performance index is constructed.

[0053] The uniformity of refrigerant distribution in a direct-cooling battery cluster thermal management device is evaluated based on coupling performance indicators.

[0054] Example 2 As a preferred embodiment of the present invention, the present invention includes a performance testing method for a direct-cooling battery cluster thermal management device, comprising the following steps: Based on thermal simulation experiments of individual battery cells, the instantaneous heat generation power and equivalent target temperature of the battery pack are determined. Specifically, this includes: Based on thermal simulation experiments of a single battery cell, the transient temperature history of the geometric center point on the bottom surface of the single battery cell was obtained. and the transient integral power of the global volumetric heat source .

[0055] The equivalent target temperature of the battery pack is: ; The instantaneous heat generation power of the battery pack is: ; In the formula, For the first The equivalent target temperature of the battery pack per operating cycle. For the first The instantaneous heat generation power of the battery pack per operating cycle, This refers to the total number of individual battery cells within the battery pack. For the operating cycle.

[0056] Based on the equivalent target temperature of the battery pack and the total heat capacity of the battery pack, the corrected value for the battery heat capacity is calculated. Specifically, this includes: Equivalent target temperature of the battery pack Perform low-pass filtering to obtain the target temperature change rate. .

[0057] Based on the target temperature change rate And the total heat capacity of the battery pack, calculate the battery heat capacity correction value: , , In the formula, For the first Battery thermal capacity correction value for each operating cycle. The total heat capacity of the battery pack. For the quality of a single battery cell, This refers to the specific heat capacity of a single battery cell. This refers to the total number of individual battery cells within the battery pack.

[0058] An electro-thermal conversion component for simulating battery pack heating is installed on the direct cooling plate of the direct cooling battery cluster thermal management device. After a set flow rate and state of refrigerant are input into the direct cooling plate, the electro-thermal conversion component is controlled to start heating.

[0059] The temperature of the electro-thermal conversion component is collected in real time. Combined with the heat capacity of the electro-thermal conversion component, the feedback correction value of the electro-thermal conversion component is determined, including: The temperature of the electro-thermal conversion component is collected in real time. Median filtering was performed to obtain the measured temperature change rate. .

[0060] Based on measured temperature change rate And the heat capacity of the electro-thermal conversion component, calculate the feedback correction value of the electro-thermal conversion component: , , In the formula, For the first Feedback correction value of the electro-thermal conversion component for each operating cycle. For the heat capacity of the electro-thermal conversion component, For the quality of the electro-thermal conversion components, This refers to the specific heat capacity of the electro-thermal conversion component.

[0061] Based on the instantaneous heat generation power of the battery pack, the battery thermal capacity correction value, and the feedback correction value of the electro-thermal conversion component, the output power of the electro-thermal conversion component is calculated, and the actual output power of the electro-thermal conversion component is dynamically adjusted based on this output power. The calculation method for the output power of the electro-thermal conversion component is as follows: , , In the formula, For the first The power output per operating cycle This represents the maximum output power of the electro-thermal conversion component. For the first Intermediate calculation power per operating cycle, For the first The instantaneous heat generation power of the battery pack per operating cycle, For the first Battery thermal capacity correction value for each operating cycle. For the first Feedback correction value of the electro-thermal conversion component for each operating cycle. For the operating cycle.

[0062] During or after the test, the refrigerant temperature at the inlet and outlet of the direct-cooling plate is collected. Based on the refrigerant temperature and the temperature of the electro-thermal conversion component, a coupled performance index is constructed.

[0063] The uniformity of refrigerant distribution in a direct-cooling battery cluster thermal management device is evaluated based on coupling performance indicators.

[0064] Example 3 In another preferred embodiment of the present invention, the present invention includes a performance testing method for a direct-cooling battery cluster thermal management device, comprising the following steps: Based on thermal simulation tests of individual battery cells, the instantaneous heat generation power and equivalent target temperature of the battery pack are determined.

[0065] The battery heat capacity correction value is calculated based on the equivalent target temperature of the battery pack and the total heat capacity of the battery pack.

[0066] Direct-cooled battery cluster thermal management device includes The device consists of several parallel refrigerant branches, each corresponding to a direct-cooling plate. Each direct-cooling plate in the direct-cooling battery cluster thermal management device is equipped with an electro-thermal conversion component to simulate battery pack heating. After a set flow rate and state of refrigerant are input into the direct-cooling plate, the electro-thermal conversion component is controlled to begin heating.

[0067] The temperature of the electro-thermal conversion component is collected in real time, and the feedback correction value of the electro-thermal conversion component is determined based on the heat capacity of the electro-thermal conversion component.

[0068] Based on the instantaneous heat generation power of the battery pack, the battery thermal capacity correction value, and the feedback correction value of the electro-thermal conversion component, the output power of the electro-thermal conversion component is calculated, and the actual output power of the electro-thermal conversion component is dynamically adjusted based on the output power.

[0069] During or after the test, the refrigerant temperature at the inlet and outlet of the direct-cooling plate is collected; based on the refrigerant temperature and the temperature of the electro-thermal conversion component, a coupled performance index is constructed: ; In the formula, For the first The coupling performance index of the branch path For the first The average temperature difference between the electro-thermal conversion component and the refrigerant in each branch circuit. for a side road The arithmetic mean; For the first The refrigerant inlet and outlet temperature rise of the branch circuit for a side road The arithmetic mean.

[0070] Based on coupling performance indices, the refrigerant distribution uniformity of the direct-cooled battery cluster thermal management device is evaluated: the coupling performance indices of all branches are calculated. Sample standard deviation ; Sample standard deviation The refrigerant distribution in the direct-cooled battery cluster thermal management device is compared with a preset threshold to determine whether the refrigerant distribution is uniform.

[0071] The coupling performance index of each branch is compared with the preset range value to identify abnormal branches.

[0072] Example 4 As another preferred embodiment of the present invention, the present invention includes a performance testing method for a direct-cooling battery cluster thermal management device, as described in the appendix to the specification. Figure 1 This includes the following steps: Based on thermal simulation tests of individual battery cells, the instantaneous heat generation power and equivalent target temperature of the battery pack are determined.

[0073] Taking a single battery cell as the object, a three-dimensional transient thermal model of the cell is established based on common finite element thermal simulation methods. The cell's geometric model is established according to its actual dimensions, and the material thermal properties (density, specific heat capacity, thermal conductivity) are obtained from the cell's product specifications and pre-test measured values. The heat source is determined using an electrochemical-thermal coupling method: standard charge-discharge conditions (0.5C constant current charge-discharge in this embodiment) are used as the input excitation. The sum of ohmic heat and polarization heat of the single cell at each moment is calculated based on the measured internal resistance-SOC curve and uniformly applied to the main body of the cell as a volume heat source. The internal resistance-SOC curve is obtained by HPPC testing at a reference temperature of 25°C; those skilled in the art can select other test temperatures according to actual operating conditions. All six outer surfaces of the cell are set as adiabatic boundary conditions, without introducing any convection or heat conduction paths to ensure the accuracy of the simulation output. Reflects the pure heat generation power of the battery cell itself; Under these conditions, the adiabatic natural temperature rise process is used to characterize the dynamic demand of the cell's thermal capacity compensation term, rather than as an absolute temperature control target.

[0074] Simulation start time Defined as the moment when discharge begins under standard charge and discharge conditions, the initial simulation temperature is set to 25℃ (adjustable according to actual operating conditions), and the simulation duration covers a complete charge and discharge cycle. After the simulation is completed, the transient temperature history of the geometric center node on the bottom surface of a single cell is extracted as... Extracting the transient integral power of the global volumetric heat source as Both are based on The time origin output is a discrete sequence with equal time intervals, and the sampling interval is consistent with the control cycle of the control unit.

[0075] For the 52S battery pack in this embodiment, each individual cell has the same specifications and operating conditions, and the heat generation power can be linearly superimposed.

[0076] Equivalent target temperature of the battery pack for: .

[0077] Instantaneous heat generation power of the battery pack for: .

[0078] Based on the equivalent target temperature and total heat capacity of the battery pack, calculate the battery heat capacity correction value. This step has no strict time dependency; it only needs to be performed after determining the equivalent target temperature of the battery pack and before calculating the power output of the electro-thermal conversion components. Specifically, the calculation method for the battery heat capacity correction value includes: Equivalent target temperature of the battery pack After applying a first-order low-pass filter, the result is Then, the derivative of the filtered data is calculated to determine the target temperature change rate. : , , In the formula, For the operating cycle, For the first The equivalent target temperature after first-order low-pass filtering is used for each operating cycle. For the first The equivalent target temperature after first-order low-pass filtering is used for each operating cycle. The sampling period is These are the filter coefficients. The value is selected based on the system sampling period. With the time constant of the filter Confirmed, the correlation formula is: The time constant of the filter Given the characteristics of large heat capacity and slow thermal response of battery cells, priority should be given to... In applications, the sampling period can be used as a reference. and time constant Actual value calculation .

[0079] In the first running cycle ( ),make , .

[0080] Because the actual heat capacity of a battery is much larger than that of the electro-thermal conversion component, during the dynamic charging and discharging process, its own temperature rise / fall will absorb or release some heat, causing the actual heat power transferred to the external heat dissipation interface to be less than (or greater than) the total heat generation power of the battery. To ensure that the heat flow transferred to the heat exchange interface is consistent with that of the actual battery, it is necessary to dynamically subtract or supplement the energy from the battery's own sensible heat change based on the target temperature change rate. Therefore, based on the target temperature change rate... And the total heat capacity of the battery pack, calculate the battery heat capacity correction value: , , In the formula, For the first Battery thermal capacity correction value for each operating cycle. The total heat capacity of the battery pack. For the quality of a single battery cell, This refers to the specific heat capacity of a single battery cell. This refers to the total number of individual battery cells in the battery pack; in this embodiment, it is 52.

[0081] heating phase, The additional power is deducted to simulate the process of the battery absorbing heat; cooling phase, It distributes additional power to simulate the process of a battery releasing heat to the outside.

[0082] The direct-cooling battery cluster thermal management device includes The device consists of several parallel branches, each equipped with a direct-cooling plate. Each direct-cooling plate in the direct-cooling battery cluster thermal management device is fitted with an electro-thermal conversion component to simulate battery pack heating. After a set flow rate and state of refrigerant are stably input into the direct-cooling plate, the electro-thermal conversion component is controlled to begin heating.

[0083] The temperature of the electro-thermal conversion component is collected in real time, and combined with the heat capacity of the component, the feedback correction value for the electro-thermal conversion component is determined. The real-time collected temperature of the electro-thermal conversion component... For the running cycle The arithmetic mean of the values ​​collected by multiple first temperature sensors. The first temperature sensors are respectively arranged at the geometric center of the electro-thermal conversion component and at the center projection of the inlet, outlet and branch / merge structure of the direct cooling plate flow channel. The sampling frequency is consistent with the control period, preferably 500ms~1s.

[0084] The calculation methods for the feedback correction value of the electro-thermal conversion component include: The temperature of the electro-thermal conversion component is collected in real time. After applying median filtering, the result is Then, the derivative of the filtered data is calculated to determine the measured rate of temperature change. : , , In the formula, For the first The temperature of the electro-thermal conversion component after median filtering during each operating cycle; For the first The temperature of the electro-thermal conversion component after median filtering after each operating cycle. For the first The temperature of the electro-thermal conversion component during each operating cycle. It is a median operation function; The sampling period. The window length is preferably set to: Considering that the thermal response time constant of a battery system is typically on the order of minutes, and under the condition that the control period is 500ms to 1s, we take... (Corresponding to an observation time of 2.5s to 10s) is sufficient to filter out power frequency and high frequency interference, and the introduced second-level delay is much smaller than the thermal response time of the battery itself.

[0085] when A dynamic growth window is used.

[0086] hour, ; hour, When there are only two numbers, the median is usually the average of the two numbers; hour, ; And so on, until... Then it enters a fixed-length window.

[0087] During dynamic heating, the electro-thermal conversion components, such as heating elements, retain some sensible heat, resulting in the actual power transferred to the heat dissipation interface being less than the electrically commanded power. Therefore, based on the measured temperature change rate... And the heat capacity of the electro-thermal conversion component, calculate the feedback correction value of the electro-thermal conversion component: , , In the formula, For the first Feedback correction value of the electro-thermal conversion component for each operating cycle. For the heat capacity of the electro-thermal conversion component, For the quality of the electro-thermal conversion components, This refers to the specific heat capacity of the electro-thermal conversion component.

[0088] To ensure the accurate heat flow to the heat exchange interface, the actual output power of the electro-thermal conversion component is dynamically adjusted. Therefore, based on the instantaneous heat generation power of the battery pack, the battery thermal capacity correction value, and the feedback correction value of the electro-thermal conversion component, the output power of the electro-thermal conversion component is calculated, and the actual output power of the electro-thermal conversion component is dynamically adjusted based on this output power. The calculation method for the output power of the electro-thermal conversion component is as follows: , , In the formula, For the first The power output per operating cycle This represents the maximum output power of the electro-thermal conversion component. For the first Intermediate calculation power per operating cycle, For the first The instantaneous heat generation power of the battery pack per operating cycle, For the first Battery thermal capacity correction value for each operating cycle. For the first Feedback correction value of the electro-thermal conversion component for each operating cycle.

[0089] The control method for the actual output power of the aforementioned electro-thermal conversion component does not introduce a separate thermal resistance correction term. The thermal resistance calibration value is affected by various factors such as refrigerant flow rate, temperature, and contact pressure. Single-condition calibration results deviating from the calibration point will introduce additional errors, thus reducing control accuracy. Taking all factors into consideration, this invention uses three terms—the instantaneous heat generation power of the battery pack, the battery thermal capacity correction value, and the feedback correction value of the electro-thermal conversion component—to constitute a complete control law, reducing calibration complexity while ensuring control accuracy.

[0090] During or after the test, the refrigerant temperature at the inlet and outlet of the direct-cooling plate is collected. Based on the refrigerant temperature and the temperature of the electro-thermal conversion component, a coupling performance index is constructed. This coupling performance index represents the degree of matching between the quantifiable heat transfer capacity and the refrigerant flow state, specifically: ; In the formula, For the first The coupling performance index of the branch path For the first The average temperature difference between the electro-thermal conversion component and the refrigerant in each branch circuit. for a side road The arithmetic mean; For the first The refrigerant inlet and outlet temperature rise of the branch circuit for a side road The arithmetic mean.

[0091] The average temperature difference between the electro-thermal conversion component and the refrigerant is a characterization of the core-driven temperature difference from heat transfer from the electro-thermal conversion component to the refrigerant within the direct-cooling plate. The calculation method is as follows: .

[0092] In the formula, For the first The average temperature difference between the electro-thermal conversion component and the refrigerant in each branch circuit. For the first The temperature of the electro-thermal conversion component of each branch, specifically the average temperature, is obtained by actual measurement using a first temperature sensor arranged on the surface of the electro-thermal conversion component. For the first The refrigerant temperature at the inlet of the direct-cooling plate in this branch circuit. For the first The refrigerant temperature at the outlet of the direct cooling plate of the branch circuit.

[0093] when A significantly larger value indicates an obstruction in the heat exchange process of this branch, requiring a larger temperature difference to drive the same heat transfer. This may be due to issues such as blockage of the direct-cooling plate flow channel, failure of the thermal interface material, or poor adhesion. A reading close to or below the average indicates that the heat exchange path of this branch is unobstructed and highly efficient.

[0094] In a direct-cooling system, the refrigerant inside the direct-cooling plate undergoes an evaporation (two-phase flow) process, which may be accompanied by outlet superheating. This assumes consistent inlet conditions and consistent heat load across all branches. Under the same stringent conditions, the temperature rise at the refrigerant inlet and outlet This primarily reflects the difference in refrigerant outlet conditions, which is directly related to the refrigerant mass flow rate flowing through this branch. Decide.

[0095] The calculation method for refrigerant inlet and outlet temperature rise is as follows: , In the formula, For the first The temperature rise of the refrigerant inlet and outlet in the branch circuit.

[0096] For refrigerant mass flow rate Smaller branch circuits: Limited refrigerant needs to absorb the same amount of heat, resulting in the evaporation process potentially completing prematurely and generating higher outlet superheat, thus leading to... and Significantly large.

[0097] For refrigerant mass flow rate An excessively large branch: Sufficient refrigerant may prolong the evaporation process, reduce the outlet dryness, or result in very little superheat, thus leading to... and Significantly small.

[0098] In this invention, the temperature rise at the refrigerant inlet and outlet is... As a sensitive indicating parameter, its value is related to the refrigerant mass flow rate of the branch. They show a roughly inverse correlation and directly reflect the differences in the degree of export overheating.

[0099] for a side road The arithmetic mean of these values ​​is used as a reference for the system's "average heat exchange temperature difference," and is calculated as follows: .

[0100] is of each branch as the arithmetic mean, which is taken as the reference benchmark for the system "average refrigerant temperature rise", and the calculation method is as follows: .

[0101] is a direct reflection of the heat transfer thermal resistance of this branch relative to the system average level, and the ideal value is 1. A value greater than 1 indicates that the heat transfer capacity of this branch is lower than the system average level.

[0102] is a direct reflection of the refrigerant temperature rise of this branch relative to the system average level. The ideal value is 1. A value greater than 1 indicates that the refrigerant temperature rise of this branch is higher than the average level. Under the same heat load, this strongly suggests that the refrigerant mass flow rate is too small, resulting in outlet superheat or significant temperature rise.

[0103] Based on the coupling performance index, the refrigerant distribution uniformity of the direct-cooling battery cluster thermal management device is evaluated: the coupling performance indexes of all branches are calculated to obtain the sample standard deviation , which is used to judge from the macro dimension whether there is a mismatch risk in the direct-cooling battery cluster thermal management device. Specifically, the sample standard deviation is compared with the preset threshold to judge the refrigerant distribution uniformity of the direct-cooling battery cluster thermal management device. If , it is determined that the refrigerant distribution uniformity of the direct-cooling battery cluster thermal management device is qualified; if , it is determined that there is a risk of refrigerant mismatch in the direct-cooling battery cluster thermal management device, and two-factor diagnosis is required.

[0104] The preset threshold is jointly determined according to the maximum allowable performance deviation rate of the heat exchange system and the confidence factor : . The maximum performance deviation rate refers to the maximum proportion of single-branch performance deviation from the average level allowed by system design, ; the confidence factor reflects the strictness of the uniformity requirement, and is taken as based on the 99.7% confidence interval.

[0105] The coupling performance index of each branch is compared with the preset interval value to identify abnormal branches. A two-factor diagnosis diagram is drawn to visually show the state of each branch and identify the abnormal cause of the abnormal branch.

[0106] The coupling performance index is obtained by taking the arithmetic mean of the ratios of the two parts, resulting in a comprehensive performance index with 1 as the ideal center value. Slight fluctuations around 1 are within the normal production and installation tolerance range and are considered uniform. The preferred fluctuation range is ±0.1. This clearly indicates that the overall condition of this branch is biased towards "poor heat exchange" and "low flow rate"; these are typical characteristics of insufficient cooling. For example, a branch with poor cooling effect due to severely insufficient flow rate will simultaneously exhibit the following characteristics: Increase ( )and Significantly increased ( The two superimpose in the same direction, making If the value is significantly greater than 1, the signal is amplified. This clearly indicates that the overall condition of this branch is biased towards "good heat exchange" and "large flow rate"; this may be due to over-cooling or the branch's performance being too excellent.

[0107] The advantage of this coupling performance index is that it does not require direct measurement of difficult-to-obtain flow rate or dryness fraction; it can evaluate the matching state of "heat exchange" and "flow" using only temperature information.

[0108] The bifactor diagnostic chart is based on Using the X-axis as the reference, Using the Y-axis, each branch is plotted as a data point (X, Y); the cause of the branch anomaly is determined by comparing the positional relationship between the data point (X, Y) and the relative ideal point (1, 1). If the data points of the abnormal branch satisfy X > 1 and Y > 1, the flow rate is judged to be low and the thermal resistance to be high, indicating insufficient flow. This suggests a problem with the design of the distributor and piping corresponding to the abnormal branch. If the data points of the abnormal branch satisfy X < 1 and Y > 1, the flow rate is judged to be high and the thermal resistance to be high, indicating excessive contact heat. This suggests a problem with the installation process and interface materials corresponding to the abnormal branch. If the data points of the abnormal branch satisfy X < 1 and Y < 1, the flow rate is judged to be high and the thermal resistance to be low, suggesting excessive flow splitting in the piping or distributor corresponding to the abnormal branch. If the data points of the abnormal branch satisfy X > 1 and Y < 1, the flow rate is judged to be low and the thermal resistance to be low, indicating an abnormal measurement area. This suggests a problem with the collected temperature data, requiring further investigation to determine the cause of the anomaly.

[0109] This system uses coupling performance indicators It enables rapid quantitative screening and utilizes a two-factor diagnostic chart to achieve intuitive and in-depth fault mode separation, thus forming a complete performance evaluation and diagnostic system from the whole to the part, from the phenomenon to the root cause.

[0110] To further verify the accuracy of the present invention in simulating the dynamic heat flow generated on the heat exchange interface of a battery pack during operation, this embodiment compares two different heat source simulation schemes with the scheme of the present invention. The core control strategies, time characteristics and physical meanings are shown in Table 1 below.

[0111] Table 1. Comparison of the present invention with the other two heat source simulation schemes. .

[0112] This comparative verification uses the measured heat generation data of the 52S battery pack under a complete charge-discharge cycle (4h) as input. The overall analysis is based on the semi-physical simulation boundary of "measured heat generation input - heat transfer simulation response". To support the data input source for the scheme comparison and to ensure the mechanistic self-consistency of the method of dynamically adjusting the actual output power of the electro-thermal conversion component of this invention, the basic thermophysical characteristics and overall energy distribution of the 52S battery pack are deconstructed, and the key calculation parameters for this comparative verification are listed in Table 2 below.

[0113] Table 2 Key Calculation Parameters .

[0114] To quantify the superiority of the present invention's method for dynamically adjusting the actual output power of the electro-thermal conversion component, within a stable window ( Within this section, the power of the present invention, the constant power method for cell heating, and the constant power method for direct cooling plate heat exchange are compared with the actual dynamic heat exchange power of the system, as detailed in the appendix to the specification. Figure 2 As shown in Table 3, the various error indicators are as follows.

[0115] Table 3. Error Comparison of the Three Methods within the Stable Window .

[0116] The normalized root mean square error (NRMSE) of the dynamic adjustment method of this invention is as low as 4.78%, which is a significant improvement of 86.38% compared to the 35.07% of the commonly used constant power method for cell heating in the industry; and also an improvement of 69.31% compared to the 15.56% of the constant power method for direct cooling plate heat exchange. This indicates that this invention can accurately capture the dynamic fluctuation characteristics of heat load over time, avoiding the fragmentation of time characteristics in the traditional constant power method.

[0117] Regarding the mean absolute deviation (MAE), the dynamic adjustment method of this invention achieves only 23.666 W, an improvement of 87.64% compared to the 191.452 W of the constant power method for cell heating, and an improvement of 71.40% compared to the 82.734 W of the constant power method for direct cooling plate heat exchange. This indicates that this invention successfully reconstructs a highly realistic actual heat load at the direct cooling plate interface after deducting the 23.33% dynamic heat storage buffer of the cell.

[0118] The maximum absolute error directly affects the safety margin of the thermal management system design. The commonly used constant power method for cell heating in the industry has a maximum absolute error as high as 333.263W, leading to distortion in heat source simulation. This invention, however, controls the maximum absolute error to 95.623W, an improvement of 71.31%. This effectively eliminates the most unfavorable instantaneous deviation in the heat source simulation process, providing high-precision boundary support for battery pack thermal performance testing.

[0119] This invention abandons the traditional approach of crudely averaging or decoupling battery heat generation. It not only closely approximates real heat transfer in terms of total energy but also achieves extreme approximation in terms of instantaneous trajectory. The order-of-magnitude improvement in various error indicators shown in Table 3 demonstrates that the dynamic adjustment method of this invention can significantly improve the realism of heat source simulation.

[0120] Example 5 As another preferred embodiment of the present invention, the present invention includes a performance testing system for a direct-cooled battery cluster thermal management device, comprising a thermal simulation test unit, a refrigerant supply unit, a thermal interaction unit, a data acquisition unit, a control unit, and a data analysis unit.

[0121] The thermal simulation test unit is used to conduct thermal simulation tests on individual battery cells to obtain the instantaneous heat generation power and equivalent target temperature of the battery pack.

[0122] The refrigerant supply unit is connected to the direct cooling plate of the direct cooling battery cluster thermal management device and is used to introduce refrigerant into the direct cooling plate.

[0123] The thermal interaction unit includes a connected electro-thermal conversion component and a programmable DC power supply. The electro-thermal conversion component is mounted on a direct cooling plate to simulate the dynamic heat flow generated at the heat exchange interface of the battery pack during operation.

[0124] The data acquisition unit is used to collect the temperature of the electro-thermal conversion component and the refrigerant temperature at the inlet and outlet of the direct cooling plate in real time.

[0125] The control unit is used to calculate the battery thermal capacity correction value based on the equivalent target temperature of the battery pack and the total thermal capacity of the battery pack; to determine the feedback correction value of the electro-thermal conversion component based on the temperature of the electro-thermal conversion component collected in real time and in combination with the thermal capacity of the electro-thermal conversion component; to calculate the output power of the electro-thermal conversion component based on the instantaneous heat generation power of the battery pack, the battery thermal capacity correction value and the feedback correction value of the electro-thermal conversion component, and to dynamically adjust the actual output power of the electro-thermal conversion component based on the output power through the programmable DC power supply.

[0126] The data analysis unit is used to construct a coupling performance index by collecting the refrigerant temperature at the inlet and outlet of the direct-cooling plate and the temperature of the electro-thermal conversion component, and to evaluate the refrigerant distribution uniformity of the direct-cooling battery cluster thermal management device based on the coupling performance index.

[0127] Example 6 In another preferred embodiment of the present invention, the present invention includes a performance testing system for a direct-cooled battery cluster thermal management device, comprising a thermal simulation test unit, a test bench unit, an environmental simulation unit, a refrigerant supply unit, a thermal interaction unit, a data acquisition unit, a control unit, a data analysis unit, an abnormal branch identification unit, and a display unit. These units work collaboratively to pre-verify the thermal management performance of the direct-cooling plate and the direct-cooling pipeline of the battery cluster before system integration.

[0128] The test bench unit includes a modularly designed test bench. The basic module is a single-module test bench, and its frame dimensions match the overall shape of the thermal interaction unit, ensuring that the installation height difference between the direct cooling plates is consistent with the actual product. Standardized positioning holes and fasteners are provided around the perimeter, allowing for rigid connection with other single-module test benches. This design enables the test bench to flexibly adapt to the testing needs of battery clusters of different specifications.

[0129] The thermal simulation test unit is used to conduct thermal simulation tests on individual battery cells to obtain the instantaneous heat generation power and equivalent target temperature of the battery pack.

[0130] The thermal interaction unit includes a programmable DC power supply and, from top to bottom, an insulation layer, a high-temperature resistant insulating frame plate, an electro-thermal conversion component, a replaceable thermal interface layer, and a direct cooling plate. The programmable DC power supply can also serve as an auxiliary device for this thermal interaction unit. The electro-thermal conversion component is preferably a thin-film heating element with dimensions matching the length and width of the battery pack. The electro-thermal conversion component is connected to the programmable DC power supply, which communicates with the control unit and receives power control commands from it. The replaceable thermal interface layer is designed to accommodate different thermally conductive materials (thermal conductive silicone, phase change materials) to match diverse thermal interface schemes in actual products. The direct cooling plate is used for heat exchange with the battery pack or the electro-thermal conversion component in this test system.

[0131] The data acquisition unit includes temperature sensors for collecting temperature data and synchronously uploading it to the control unit. Specifically, the data acquisition unit includes a first temperature sensor for real-time acquisition of the temperature of the electro-thermal conversion component, a second temperature sensor for acquiring the refrigerant temperature at the inlet of the direct-cooling plate, and a third temperature sensor for acquiring the refrigerant temperature at the outlet of the direct-cooling plate. The second temperature sensor is located at the inlet of the direct-cooling plate, and the third temperature sensor is located at the outlet of the direct-cooling plate. There can be several first temperature sensors, which are respectively located between the electro-thermal conversion component and the thermal interface layer. The placement rules for the first temperature sensors are as follows: Core monitoring point (1 location): Geometric center of the electro-thermal conversion component, such as the heating element. Flow channel inlet point (1 location): Projected position corresponding to the inlet of the direct-cooling plate flow channel. Flow channel outlet point (1 location): Projected position corresponding to the outlet of the direct-cooling plate flow channel. Topology node (M location): Projected position of the center of the branching and merging points corresponding to the design of the direct-cooling plate flow channel. If multiple parallel branches exist, at least one monitoring point should be set before the longest path branch merges.

[0132] Since the flow distribution density is determined by the points of divergence and convergence, which in turn determine the local heat transfer intensity, the average value obtained by sampling the above-mentioned points in this embodiment is more thermodynamically representative than that obtained by equally spaced points.

[0133] Furthermore, the insulation layer, high-temperature resistant insulating frame board, electro-thermal conversion component, first temperature sensor, and replaceable thermal interface layer are integrated into a single "simulated thermal load module," achieving an integrated modular structure. The first temperature sensor of this module is wired to the data acquisition unit, avoiding repetitive wiring for each experiment and improving module independence and bench tidiness.

[0134] The refrigerant supply unit includes a direct cooling unit and piping. The direct cooling unit is designed with redundancy based on the maximum heat load of the battery cluster. Its core function is to provide refrigerant with controllable temperature, pressure, and flow rate to the inside of the direct cooling plate to cool the electro-thermal conversion components.

[0135] The environmental simulation unit is used to accurately simulate ambient temperature and humidity. Specifically, the environmental simulation unit can be a variable temperature and humidity chamber. The entire test bench unit is placed inside this variable temperature and humidity chamber. This variable temperature and humidity chamber can precisely control the ambient temperature and humidity according to the test requirements.

[0136] The control unit is used to calculate the battery thermal capacity correction value based on the equivalent target temperature of the battery pack and the total thermal capacity of the battery pack. It is also used to determine the feedback correction value of the electro-thermal conversion component based on the real-time collected temperature of the electro-thermal conversion component and its thermal capacity. Furthermore, it is used to calculate the output power of the electro-thermal conversion component based on the instantaneous heat generation power of the battery pack, the battery thermal capacity correction value, and the feedback correction value of the electro-thermal conversion component, and dynamically adjust the actual output power of the electro-thermal conversion component based on this output power using a programmable DC power supply. Specific calculation methods can refer to the calculation methods described in the embodiments of the test methods belonging to the same inventive concept.

[0137] The data analysis unit is used to construct a coupling performance index using the collected refrigerant temperatures at the inlet and outlet of the direct-cooling plate and the temperature of the electro-thermal conversion component. Based on the coupling performance index, it quantifies the degree of matching between heat transfer capacity and refrigerant flow state, thereby evaluating the uniformity of refrigerant distribution in the direct-cooling battery cluster thermal management device. Specific evaluation methods can refer to the evaluation methods described in the embodiments of the test methods belonging to the same inventive concept.

[0138] The direct-cooling battery cluster thermal management device includes The system consists of several parallel branches, each equipped with a direct cooling plate. The abnormal branch identification unit is used to identify abnormal branches by comparing the coupling performance index of each branch with a preset range value.

[0139] The display unit is used to draw a two-factor diagnostic chart, which visually displays the status of each branch. The two-factor diagnostic chart uses... Using the X-axis as the reference, Using the Y-axis as the plotting axis, each branch is plotted as a data point (X, Y); the cause of the branch anomaly is determined by comparing the positional relationship between the data point (X, Y) and the relative ideal point (1, 1).

[0140] In the formula, For the first The average temperature difference between the electro-thermal conversion component and the refrigerant in each branch circuit. for a side road The arithmetic mean; For the first The refrigerant inlet and outlet temperature rise of the branch circuit for a side road The arithmetic mean.

[0141] This system uses coupling performance indicators It enables rapid quantitative screening and utilizes a two-factor diagnostic chart to achieve intuitive and in-depth fault mode separation, thus forming a complete performance evaluation and diagnostic system from the whole to the part, from the phenomenon to the root cause.

[0142] The usage method of the above testing system is as follows: Step 1. System Setup and Initialization. Place the thermal interaction unit on the single-module test bench. Assemble the single-module test bench into a battery cluster and connect the direct cooling pipeline of the battery cluster. Move the assembled test bench into the variable temperature and humidity chamber; install the temperature sensor according to the test requirements, connect it to the data analysis unit and communicate with the control unit; connect the electro-thermal conversion component to the programmable DC power supply, and connect the programmable DC power supply to the control unit. Connect the direct cooling pipeline of the battery cluster and the refrigerant supply unit, and check the system's sealing performance.

[0143] Step 2. Obtain the thermal simulation output results and the results of the preliminary tests.

[0144] The transient temperature history of the geometric center point on the bottom surface of a single battery cell was obtained through thermal simulation. and the transient integral power of the global volumetric heat source The specific heat capacity of a single battery cell was determined through preliminary tests. Individual cell quality Specific heat capacity of electro-thermal conversion components and the quality of the electro-thermal conversion components .

[0145] Step 3. Set the test conditions and start the test.

[0146] Start the variable temperature and humidity chamber and wait for the ambient temperature and humidity to reach the target values. Start the refrigeration unit and set the operating parameters according to the test requirements. That is, after the refrigerant with the set flow rate and state is stably input into the direct cooling plate, the programmable DC power supply issues the initial power command to drive the electro-thermal conversion component to start heating.

[0147] Step 4. Real-time temperature acquisition and dynamic power regulation are used to control the electro-thermal conversion component to reproduce the transient temperature rise curve of the large inertial battery pack.

[0148] The measured temperature acquisition specifically refers to: real-time acquisition of the temperature of the electro-thermal conversion component. Refrigerant temperature at the inlet of the direct-cooling plate and the refrigerant temperature at the outlet of the direct cooling plate Among them, the measured temperature of the electro-thermal conversion component. For the running cycle The arithmetic mean of the values ​​collected by multiple first temperature sensors.

[0149] The dynamic power regulation is based on the instantaneous heat generation power of the battery pack, the calculated battery heat capacity correction value, and the calculated feedback correction value of the electro-thermal conversion component. The output power of the electro-thermal conversion component is calculated, and the actual output power of the electro-thermal conversion component is dynamically adjusted based on the output power.

[0150] Step 5. Construct coupling performance indicators to complete the evaluation of refrigerant distribution uniformity of the direct-cooled battery cluster thermal management device.

[0151] In summary, any other corresponding modifications made by those skilled in the art after reading this invention document, without requiring creative mental effort, based on the technical solutions and concepts of this invention, are all within the scope of protection of this invention.

Claims

1. A performance testing method for a direct-cooling battery cluster thermal management device, characterized in that: Includes the following steps: Based on thermal simulation experiments of individual battery cells, the instantaneous heat generation power and equivalent target temperature of the battery pack are determined, including: obtaining the transient temperature history of the geometric center point of the bottom surface of the individual battery cell based on thermal simulation experiments of individual battery cells. and the transient integral power of the global volumetric heat source ; The equivalent target temperature of the battery pack is determined as follows: ; The instantaneous heat generation power of the battery pack is determined as follows: ; In the formula, For the first The equivalent target temperature of the battery pack per operating cycle. For the first The instantaneous heat generation power of the battery pack per operating cycle, This refers to the total number of individual battery cells within the battery pack. For the running cycle; Based on the equivalent target temperature and total heat capacity of the battery pack, calculate the battery heat capacity correction value, including: the equivalent target temperature of the battery pack. The target temperature change rate is obtained by performing low-pass filtering and differentiation sequentially. Based on the target temperature change rate And the total heat capacity of the battery pack, calculate the battery heat capacity correction value: ， In the formula, For the first Battery thermal capacity correction value for each operating cycle. Total heat capacity of the battery pack; An electro-thermal conversion component for simulating battery pack heating is installed on the direct cooling plate of the direct cooling battery cluster thermal management device. After a refrigerant with a set flow rate and state is input into the direct cooling plate, the electro-thermal conversion component is controlled to start heating. The temperature of the electro-thermal conversion component is collected in real time, and combined with the heat capacity of the component, the feedback correction value of the electro-thermal conversion component is determined: the real-time collected temperature of the electro-thermal conversion component... Median filtering and differentiation were performed sequentially to obtain the measured temperature change rate. Based on measured temperature change rate And the heat capacity of the electro-thermal conversion component, calculate the feedback correction value of the electro-thermal conversion component: ， In the formula, For the first Feedback correction value of the electro-thermal conversion component for each operating cycle. The heat capacity of the electro-thermal conversion component; Based on the instantaneous heat generation power of the battery pack, the battery thermal capacity correction value, and the feedback correction value of the electro-thermal conversion component, the output power of the electro-thermal conversion component is calculated, and the actual output power of the electro-thermal conversion component is dynamically adjusted based on this output power; the calculation method for the output power of the electro-thermal conversion component is as follows: ， ， In the formula, For the first The power output per operating cycle This represents the maximum output power of the electro-thermal conversion component. For the first Intermediate computational power per operating cycle; The direct-cooling battery cluster thermal management device includes A series of parallel branches, each equipped with a direct-cooling plate; during or after the test, the refrigerant temperature at the inlet and outlet of the direct-cooling plate is collected; based on the refrigerant temperature and the temperature of the electro-thermal conversion component, a coupling performance index is constructed: ； In the formula, For the first The coupling performance index of the branch is as follows: For the first The average temperature difference between the electro-thermal conversion component and the refrigerant in each branch circuit. for a side road The arithmetic mean; For the first The refrigerant inlet and outlet temperature rise of the branch circuit for a side road The arithmetic mean; The uniformity of refrigerant distribution in a direct-cooling battery cluster thermal management device is evaluated based on coupling performance indicators.

2. The performance testing method for a direct-cooling battery cluster thermal management device according to claim 1, characterized in that: The method for calculating the total heat capacity of the battery pack is as follows: ， In the formula, For the quality of a single battery cell, This refers to the specific heat capacity of a single battery cell.

3. The performance testing method for a direct-cooling battery cluster thermal management device according to claim 1, characterized in that: The method for calculating the heat capacity of an electro-thermal conversion component is as follows: ， In the formula, For the quality of the electro-thermal conversion components, This refers to the specific heat capacity of the electro-thermal conversion component.

4. The performance testing method for a direct-cooling battery cluster thermal management device according to claim 1, characterized in that: Equivalent target temperature of the battery pack The process involves sequential low-pass filtering and differentiation, specifically targeting the equivalent target temperature of the battery pack. After applying a first-order low-pass filter, the result is Then, the derivative of the filtered data is calculated to determine the target temperature change rate. : ， ， In the formula, For the operating cycle, For the first The equivalent target temperature after first-order low-pass filtering is used for each operating cycle. For the first The equivalent target temperature after first-order low-pass filtering is used for each operating cycle. These are the filter coefficients. The sampling period.

5. The performance testing method for a direct-cooling battery cluster thermal management device according to claim 1, characterized in that: The temperature of the electro-thermal conversion component is collected in real time. Median filtering and differentiation are performed sequentially, specifically referring to the real-time temperature data of the electro-thermal conversion component. After applying median filtering, the result is Then, the derivative of the filtered data is calculated to determine the measured rate of temperature change. : ， ， In the formula, For the operating cycle, For window length, For the first The temperature of the electro-thermal conversion component after median filtering during each operating cycle; For the first The temperature of the electro-thermal conversion component after median filtering after each operating cycle. For the first The temperature of the electro-thermal conversion component during each operating cycle. It is a median operation function; The sampling period.

6. The performance testing method for a direct-cooling battery cluster thermal management device according to claim 1, characterized in that: The method for calculating the average temperature difference between the electro-thermal conversion component and the refrigerant is as follows: ， The calculation method for refrigerant inlet and outlet temperature rise is as follows: ， In the formula, For the first The average temperature difference between the electro-thermal conversion component and the refrigerant in each branch circuit. For the first The refrigerant inlet and outlet temperature rise of the branch circuit For the first The temperature of the electro-thermal conversion component in each branch, For the first The refrigerant temperature at the inlet of the direct-cooling plate in this branch circuit. For the first The refrigerant temperature at the outlet of the direct cooling plate of the branch circuit.

7. The performance testing method for a direct-cooling battery cluster thermal management device according to claim 1, characterized in that: The refrigerant distribution uniformity of the direct-cooled battery cluster thermal management device is evaluated, specifically by calculating the coupling performance indices of all branches. Sample standard deviation ; Sample standard deviation The refrigerant distribution of the direct-cooled battery cluster thermal management device is compared with a preset threshold to determine whether the refrigerant distribution is uniform.

8. The performance testing method for a direct-cooling battery cluster thermal management device according to claim 7, characterized in that: Also includes: The coupling performance index of each branch is compared with the preset range value to identify abnormal branches.

9. The performance testing method for a direct-cooling battery cluster thermal management device according to claim 8, characterized in that: Also includes: A two-factor diagnostic chart is drawn to visually display the status of each branch and identify the causes of abnormality in abnormal branches; The bifactor diagnostic chart is based on Using the X-axis as the reference, Using the Y-axis, each branch is plotted as a data point (X, Y).

10. The performance testing method for a direct-cooling battery cluster thermal management device according to claim 9, characterized in that: The causes of anomalies in abnormal branches are identified by comparing the positional relationship between data points (X, Y) and the relative ideal point (1, 1). If the data points of the abnormal branch satisfy X > 1 and Y > 1, then there is a problem with the design of the distributor and pipeline corresponding to the abnormal branch; if the data points of the abnormal branch satisfy X < 1 and Y > 1, then there is a problem with the installation process and interface materials corresponding to the abnormal branch; if the data points of the abnormal branch satisfy X < 1 and Y < 1, then there is an over-diversion problem in the pipeline or distributor corresponding to the abnormal branch; if the data points of the abnormal branch satisfy X > 1 and Y < 1, then there is a problem with the collected temperature data.

11. A performance testing system for a direct-cooled battery cluster thermal management device, used to implement the performance testing method for the direct-cooled battery cluster thermal management device as described in claim 1, characterized in that: It includes a thermal simulation test unit, a refrigerant supply unit, a thermal interaction unit, a data acquisition unit, a control unit, and a data analysis unit; The thermal simulation test unit is used to conduct thermal simulation tests on individual battery cells to obtain the instantaneous heat generation power and equivalent target temperature of the battery pack. The refrigerant supply unit is connected to the direct cooling plate of the direct cooling battery cluster thermal management device and is used to introduce refrigerant into the direct cooling plate. The thermal interaction unit includes a connected electro-thermal conversion component and a programmable DC power supply; the electro-thermal conversion component is mounted on the direct cooling plate and is used to simulate the dynamic heat flow generated at the heat exchange interface during the operation of the battery pack. The data acquisition unit is used to collect the temperature of the electro-thermal conversion component and the refrigerant temperature at the inlet and outlet of the direct cooling plate in real time; The control unit is used to calculate the battery thermal capacity correction value based on the equivalent target temperature of the battery pack and the total thermal capacity of the battery pack. It is used to determine the feedback correction value of the electro-thermal conversion component based on the real-time temperature of the electro-thermal conversion component and its thermal capacity; it is used to calculate the output power of the electro-thermal conversion component based on the instantaneous heat generation power of the battery pack, the battery thermal capacity correction value, and the feedback correction value of the electro-thermal conversion component, and to dynamically adjust the actual output power of the electro-thermal conversion component through a programmable DC power supply. The data analysis unit is used to construct a coupling performance index by collecting the refrigerant temperature at the inlet and outlet of the direct-cooling plate and the temperature of the electro-thermal conversion component, and to evaluate the refrigerant distribution uniformity of the direct-cooling battery cluster thermal management device based on the coupling performance index.

12. The performance testing system for a direct-cooled battery cluster thermal management device according to claim 11, characterized in that: The temperature of the electro-thermal conversion component collected in real time is the operating cycle. The arithmetic mean of the data collected by multiple temperature sensors.

13. The performance testing system for a direct-cooled battery cluster thermal management device according to claim 12, characterized in that: The multiple temperature sensors are respectively arranged at the geometric center of the electro-thermal conversion component and at the center projection of the inlet, outlet and split / merge structure of the direct cooling plate channel.

14. The performance testing system for a direct-cooled battery cluster thermal management device according to any one of claims 11 to 13, characterized in that: It also includes an abnormal branch identification unit; the direct-cooled battery cluster thermal management device includes The system has several parallel branches, each equipped with a direct cooling plate; the abnormal branch identification unit is used to identify abnormal branches based on the comparison of the coupling performance index of each branch with a preset range value.

15. The performance testing system for a direct-cooled battery cluster thermal management device according to claim 14, characterized in that: It also includes a display unit for drawing a two-factor diagnostic chart to visually display the status of each branch; the two-factor diagnostic chart uses... Using the X-axis as the reference, Using the Y-axis as the plotting axis, each branch is plotted as a data point (X, Y); the cause of the branch anomaly is determined by comparing the positional relationship between the data point (X, Y) and the relative ideal point (1, 1). In the formula, For the first The average temperature difference between the electro-thermal conversion component and the refrigerant in each branch circuit. for a side road The arithmetic mean; For the first The refrigerant inlet and outlet temperature rise of the branch circuit for a side road The arithmetic mean.

16. The performance testing system for a direct-cooled battery cluster thermal management device according to claim 15, characterized in that: It also includes an environmental simulation unit for simulating ambient temperature and humidity.

17. The performance testing system for a direct-cooled battery cluster thermal management device according to claim 15, characterized in that: The thermal interaction unit also includes a replaceable thermal interface layer; the thermal interface layer is disposed between the electro-thermal conversion component and the direct cooling plate.

Images