Methods, equipment and storage media for obtaining the heat transfer coefficient of battery systems

Abstract

This application provides a method, device, and storage medium for obtaining the heat transfer coefficient of a battery system. The method includes: receiving the temperature, current, voltage, and time of temperature change of a battery cell reported by a battery management system; determining the heating power based on the current and voltage of the battery cell, determining the temperature change based on the temperature, and determining the increase in internal energy based on the temperature change; determining the heat transfer power of the battery cell based on the heating power, the increase in internal energy, and the time of temperature change; determining the heat transfer power between the battery cell and any area in contact with the battery cell based on the heat transfer power, the battery cell temperature, and the temperature of any area in contact with the battery cell; and determining the heat transfer coefficient between the battery cell and any area in contact with the battery cell based on the heat transfer power, the contact area, the battery cell temperature, and the temperature of any area in contact with the battery cell. This method involves less computation and improves computational efficiency.

Description

Technical Field

[0001] This application relates to the field of battery systems, and more particularly to a method, device and storage medium for obtaining the heat transfer coefficient of a battery system. Background Technology

[0002] The heat transfer coefficient, under steady-state heat transfer conditions with a 1-degree temperature difference across the building envelope, represents the amount of heat transferred per unit time per unit area, reflecting the intensity of the heat transfer process. For battery systems, different applications and operating modes have varying requirements for the heat transfer coefficient; therefore, it is necessary to obtain the battery system's heat transfer coefficient to meet the needs of different applications.

[0003] Existing methods for obtaining heat transfer coefficients are based on establishing a single-cell-level finite element model within the battery system, and calculating the heat transfer coefficient of a single cell based on the physicochemical properties of the materials inside the cell.

[0004] Because the calculation of heat transfer coefficient based on the finite element model at the single cell level is very computationally intensive, extending it to battery systems would place a heavy computational burden on existing computer systems and result in low computational efficiency. Summary of the Invention

[0005] This application provides a method, device, and storage medium for obtaining the heat transfer coefficient of a battery system, in order to solve the problem of low efficiency in calculating the heat transfer coefficient of a battery system.

[0006] In a first aspect, this application provides a method for obtaining a heat transfer system for a battery system, comprising:

[0007] Receive data from the battery management system, including the temperature, current, voltage, and time of temperature changes in the battery cells.

[0008] The heating power of the battery cell is determined based on its current and voltage; the temperature change of the battery cell is determined based on its temperature; and the increase in the internal energy of the battery cell is determined based on the temperature change.

[0009] The heat transfer power of the battery cell is determined based on the cell's heating power, the increase in its internal energy, and the time it takes for the cell's temperature to change.

[0010] The heat transfer power between the battery cell and any area in contact with the battery cell is determined based on the heat transfer power of the battery cell, the temperature of the battery cell, and the temperature of any area in contact with the battery cell.

[0011] The heat transfer coefficient between the battery cell and any region in contact with the battery cell is determined based on the heat transfer power between the battery cell and any region in contact with the battery cell, the contact area, the temperature of the battery cell, and the temperature of any region in contact with the battery cell.

[0012] Secondly, this application provides a device for obtaining the heat transfer coefficient of a battery system, comprising:

[0013] The receiving module is used to receive the temperature, current, and time of temperature change of the cells in the battery system reported by the battery management system.

[0014] The determination module is used to determine the heating power of the battery cell based on the current and voltage of the battery cell, determine the temperature change of the battery cell based on the temperature of the battery cell, and determine the increase in internal energy of the battery cell based on the temperature change of the battery cell.

[0015] The determination module is also used to determine the heat transfer power of the battery cell based on the heating power of the battery cell, the increase in the internal energy of the battery cell, and the time it takes for the battery cell temperature to change.

[0016] The determining module is also used to determine the heat transfer power between the battery cell and any area in contact with the battery cell based on the heat transfer power of the battery cell, the temperature of the battery cell, and the temperature of any area in contact with the battery cell.

[0017] The determining module is also used to determine the heat transfer coefficient between the battery cell and any region in contact with the battery cell based on the heat transfer power between the battery cell and any region in contact with the battery cell, the contact area, the temperature of the battery cell and the temperature of any region in contact with the battery cell.

[0018] Thirdly, this application provides a battery system heat transfer coefficient acquisition device, comprising: a processor, a memory, code stored in the memory, and code stored in the processor memory to execute the battery system heat transfer system acquisition method as described in any of the first aspects.

[0019] Fourthly, this application provides a computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, are used to implement the battery system heat transfer system acquisition method as described in any of the first aspects.

[0020] Fifthly, this application provides a computer program product, including a computer program that, when executed by a processor, implements the battery system heat transfer system acquisition method of any one of the first aspects.

[0021] This application provides a method, device, and storage medium for obtaining the heat transfer coefficient of a battery system. It receives data from a battery management system, including the temperature, current, voltage, and time of temperature change of the battery cells. The method determines the heating power of the battery cell based on its current and voltage, determines the temperature change based on its temperature, and determines the increase in internal energy based on the temperature change. The method also determines the heat transfer power of the battery cell based on its heating power, increase in internal energy, and time of temperature change. Since the battery cell contacts multiple areas, the method determines the heat transfer power between the battery cell and any area in contact with it, based on the heat transfer power, temperature, and temperature of any area in contact with the battery cell. Finally, the method determines the heat transfer coefficient between the battery cell and any area in contact with it, based on the heat transfer power and contact area, the temperature of the battery cell, and the temperature of any area in contact with the battery cell. The method provided in this application calculates the heating power, increase in internal energy, and heat transfer power of the battery cell by measuring the current, voltage, temperature, and time of temperature change. This allows the determination of the heat transfer coefficient between the battery cell and any region in contact with it, with a relatively small computational load, thus improving computational efficiency. Attached Figure Description

[0022] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0023] Figure 1 A schematic diagram of a system architecture for obtaining heat transfer coefficient is provided in an embodiment of this application;

[0024] Figure 2 A method flow for obtaining the heat transfer coefficient of a battery system provided in this application embodiment Figure 1 ;

[0025] Figure 3 A method flow for obtaining the heat transfer coefficient of a battery system provided in this application embodiment Figure 2 ;

[0026] Figure 4 A flowchart illustrating a method for obtaining the heat transfer coefficient of a new energy vehicle battery module, provided in an embodiment of this application;

[0027] Figure 5 This application provides a top view schematic diagram of a new energy vehicle battery pack as an embodiment of the present application;

[0028] Figure 6 A schematic diagram of a battery system heat transfer coefficient acquisition device provided in this application embodiment. Figure 1 ;

[0029] Figure 7 A schematic diagram of a battery system heat transfer coefficient acquisition device provided in this application embodiment. Figure 2 .

[0030] The accompanying drawings have illustrated specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to specific embodiments. Detailed Implementation

[0031] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0032] The heat transfer coefficient (K-value) refers to the amount of heat transferred per unit time through a unit area under steady-state heat transfer conditions, where the temperature difference between the two sides of an enclosure is 1 degree Celsius (K, °C). The unit is watts per square meter per degree Celsius (W / ㎡•K, where K can be replaced by °C). The heat transfer coefficient reflects the strength of the heat transfer process and is essentially determined by the intrinsic thermophysical properties of the heat transfer medium. A higher heat transfer coefficient indicates a stronger heat transfer capacity and better heat dissipation, but poorer thermal insulation performance; conversely, a lower heat transfer coefficient indicates a weaker heat transfer capacity and poorer heat dissipation, but better thermal insulation performance.

[0033] For battery systems, different applications and operating modes have different requirements for heat transfer coefficients. For example, a closed-structure containerized energy storage system equipped with central air conditioning requires a relatively high heat transfer coefficient to ensure proper temperature control within the battery system and temperature balance between different parts of the system. For new energy vehicle battery pack systems equipped with liquid cooling systems, a relatively low heat transfer coefficient is needed when the liquid cooling system is not in operation to ensure good insulation in cold regions; while a high heat transfer coefficient is needed when the liquid cooling system is in operation to ensure good heat dissipation during high-power charging and discharging. This change in system heat transfer coefficient essentially reflects the change in the overall equivalent thermal properties of the system caused by changes in the system control structure.

[0034] Current methods for obtaining heat transfer coefficients involve establishing a single-cell-level finite element model and calculating the heat transfer coefficient of the single cell based on the physicochemical properties of the internal materials. Since single-cell-level finite element models typically involve significant computational loads, extending them to the entire battery system results in numerous finite element models operating simultaneously and being coupled with each other. This places a heavy computational burden on existing computer systems, leading to low computational efficiency.

[0035] This application provides a method for obtaining the heat transfer coefficient of a battery system. It receives data from the battery management system, including the cell's temperature, current, voltage, and the time it takes for the cell's temperature to change. The heating power of the cell is determined based on its current and voltage. The temperature change is determined based on the cell's temperature, which in turn determines the increase in the cell's internal energy. The heat transfer power of the cell is determined based on its heating power, the increase in internal energy, and the time it takes for the temperature to change. Since the cell can contact multiple areas, the heat transfer power between the cell and any area in contact with the cell can be determined based on the cell's heat transfer power, temperature, and the temperature of any area in contact with the cell. Finally, the heat transfer coefficient between the cell and any area in contact with the cell is determined based on the heat transfer power, the contact area, the cell's temperature, and the temperature of any area in contact with the cell. The method provided in this application is based on relevant parameters such as the current, voltage, temperature, and time of temperature change of the battery cell. It can calculate the heating power, increase in internal energy, and heat transfer power of the battery cell, and thus determine the heat transfer coefficient of the battery cell. It does not require the establishment of a finite element model based on the battery cell, and the amount of calculation is small, which improves the calculation efficiency of the heat transfer coefficient.

[0036] Figure 1 A schematic diagram of a system architecture for obtaining the heat transfer coefficient is provided in an embodiment of this application, as shown below. Figure 1 As shown, the battery system contains multiple cells. The battery management system can detect the current, voltage, temperature, and the time it takes for the temperature to change in each cell, and report this data to the data platform. Based on parameters such as current, voltage, temperature, and the time it takes for the temperature to change, the data platform can remotely calculate the cell's heat generation power, increase in internal energy, and heat transfer power, thereby determining the heat transfer coefficient. Alternatively, the heat transfer coefficient can also be determined offline when calculating parameters such as current, voltage, temperature, and the time it takes for the temperature to change.

[0037] The following specific embodiments describe in detail the technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0038] Figure 2 A method flow for obtaining the heat transfer coefficient of a battery system provided in this application embodiment Figure 1 The method in this embodiment can be executed by a battery system heat transfer coefficient acquisition device, and can be implemented through hardware, software, or a combination of hardware and software. For example... Figure 2 As shown, the method provided in this application may include:

[0039] S201: Receives data from the battery management system regarding the temperature, current, voltage, and time of temperature changes in the battery cells.

[0040] A battery system can contain multiple cells, where a cell is a single cell or a packaged assembly of multiple consecutive cells. Generally, the temperature of the cells will rise during the charging and discharging process of a battery system.

[0041] S202: Determine the heating power of the battery cell based on the current and voltage of the battery cell, determine the temperature change of the battery cell based on the temperature of the battery cell, and determine the increase in internal energy of the battery cell based on the temperature change of the battery cell.

[0042] The heat generation power of a battery cell includes one or more of the following: heat generation power from the main reaction, heat generation power from the secondary reaction, heat generation power from entropy change, and heat generation power caused by electrical connections. Among them, the heat generation power caused by electrical connections includes the heat generation power of the battery cell caused by electrical connections, and the heat generation power of electrical components and contact internal resistance.

[0043] The main reaction refers to the oxidation-reduction reaction that occurs during the charging and discharging of the battery cell. The heating power of the main reaction can be determined by the current of the battery cell and the main reaction coefficient.

[0044] Side reactions are derivative reactions that occur during the charging and discharging process of the battery cell. They can manifest as continuous small discharges or gas generation during the charging and discharging process. The heating power of the side reactions can be determined by the side reaction current and the battery cell voltage.

[0045] Entropy change in a battery cell is the energy throughput process involved in the phase transition during the reaction of the cell's active materials. The entropy change heating power of the cell can be determined by the cell current, temperature, and open-circuit voltage.

[0046] Because the battery cell has a certain resistance, electrical connections cause it to heat up. The heat generated by these connections includes not only the cell's own heat output but also the heat generated by the contact resistance between the cell and the electrical components, as well as the heat generated by the internal resistance of the internal components within the cell. The contact resistance refers to the internal resistance at the point of contact between the cell and the external electrical components. These electrical components can be devices that connect different battery cells; they can be copper busbars, aluminum busbars, or other composite metals.

[0047] Since the temperature of the battery cell increases as the cell is charged and discharged, the increase in the cell's internal energy can be determined based on the change in the cell's temperature.

[0048] S203: Determine the heat transfer power of the battery cell based on the cell's heating power, the increase in the cell's internal energy, and the time it takes for the cell's temperature to change.

[0049] During the charging and discharging process of a battery cell, the cell temperature continuously increases, indicating that the cell has not yet reached a thermal steady state. When the cell temperature reaches a certain threshold, it stops increasing and remains constant, at which point the cell has reached a thermal steady state.

[0050] Since the heat generation power of a battery cell can be divided into two parts: the power of internal energy increase and the power of heat transfer, where the internal energy increase power represents the rate of temperature rise of the battery system, and the heat transfer power represents the power of heat transfer between the cell and its contact areas, in one implementation scenario, if the battery system reaches a thermal steady state, the cell temperature remains constant, the cell's internal energy no longer increases (i.e., the increase in internal energy is 0), and the cell's heat transfer power is equal to its heat generation power.

[0051] In another implementation scenario, if the battery system has not reached thermal steady state, the cell will undergo heat transfer as its internal energy gradually increases. Therefore, the heat transfer power of the cell can be equal to the difference between the cell's heating power and the power of the increase in internal energy. The power of the increase in internal energy can be determined by the amount of increase in the cell's internal energy and the time it takes for the cell's temperature to change.

[0052] It should be noted that, generally speaking, heat transfer occurs from the high-temperature part to the low-temperature part.

[0053] S204: Determine the heat transfer power between the battery cell and any area in contact with the battery cell based on the heat transfer power of the battery cell, the temperature of the battery cell, and the temperature of any area in contact with the battery cell.

[0054] Any area in contact with the battery cell can be a single battery cell, a collection of battery cells and other components within any continuous area, or the external environment.

[0055] When a battery cell comes into contact with multiple areas, the distribution of heat transfer power is proportional to the temperature difference between the battery cell and the areas in contact with it. Therefore, a feasible way to calculate heat transfer power is to calculate it based on the ratio of the temperature difference between the battery cell and any area in contact with it to the sum of the temperature differences between the battery cell and all areas in contact with it.

[0056] S205: Determine the heat transfer coefficient between the battery cell and any area in contact with the battery cell based on the heat transfer power between the battery cell and any area in contact with the battery cell, the contact area, the temperature of the battery cell and the temperature of any area in contact with the battery cell.

[0057] The heat transfer coefficient is the amount of heat transferred per unit area per unit time, and it can reflect the strength of the heat transfer process.

[0058] A feasible method for calculating the heat transfer coefficient is as follows:

[0059]

[0060] In the formula, i represents the battery cell, and j represents any region in contact with the battery cell. This represents the heat transfer coefficient between parts i and j. This represents the heat transfer power between parts i and j. This represents the contact area between i and j. Indicates the average temperature of i. This represents the average temperature of j.

[0061] This application provides a method for obtaining the heat transfer coefficient of a battery system. The method receives data from a battery management system, including the temperature, current, voltage, and time of temperature change of the battery cells. The heating power of the battery cell is determined based on its current and voltage. The temperature change is determined based on its temperature, and the increase in internal energy of the battery cell is determined based on the temperature change. The heat transfer power of the battery cell is determined based on its heating power, the increase in internal energy, and the time of temperature change. The heat transfer power between the battery cell and any area in contact with it is determined based on its heat transfer power, temperature, and the temperature of any region in contact with the battery cell. Finally, the heat transfer coefficient between the battery cell and any area in contact with it is determined based on the heat transfer power, the contact area, the temperature of the battery cell, and the temperature of any region in contact with the battery cell. The heat transfer coefficient acquisition method provided in this application calculates the heating power, internal energy increase and heat transfer power of the battery cell based on the current, voltage, temperature and temperature change time of the battery cell, and determines the heat transfer coefficient of a single battery cell, a collection of multiple continuous battery cells and the battery system. It does not require the establishment of a finite element model, has a small amount of calculation, and improves the calculation efficiency.

[0062] Based on the above embodiments, a specific embodiment is provided below to describe in detail the process of obtaining the heat transfer coefficient of the battery system.

[0063] Figure 3 A method flow for obtaining the heat transfer coefficient of a battery system provided in this application embodiment Figure 2 ,like Figure 3 As shown, the specific method is as follows:

[0064] S301: Receives data from the battery management system regarding the temperature, current, voltage, and time of temperature changes of the cells in the battery system.

[0065] A battery system can contain multiple cells, and the temperature of the cells will vary depending on their location.

[0066] A battery cell can be a single cell or a packaged collection of multiple consecutive cells, or it can be the entire battery system.

[0067] S302: Determine the heating power of the battery cell based on the current and voltage of the battery cell, determine the temperature change of the battery cell based on the temperature of the battery cell, and determine the increase in internal energy of the battery cell based on the temperature change of the battery cell.

[0068] The heating power of a battery cell can include one or more of the following: heating power from the main reaction, heating power from the secondary reaction, heating power from entropy change, and heating power caused by electrical connections. Among these, the heating power caused by electrical connections includes the heating power of the battery cell due to electrical connections, and the heating power from electrical components and contact internal resistance.

[0069] The heating power of the battery cell caused by electrical connections can be calculated using the following formula:

[0070]

[0071] in, The heat generated by the battery cell due to electrical connections. The current of the battery cell, This represents the internal resistance of the battery cell.

[0072] In addition to the calculation methods described above, the heat generated by electrical connections can also be calculated using the following formula:

[0073]

[0074] In the formula, The heat generated by the battery cell due to electrical connections. The current of the battery cell, This is the polarization voltage of the battery cell. and They are in the same direction, meaning they have the same sign.

[0075] The heating power of the main reaction can be determined by the following formula:

[0076]

[0077] In the formula, The current of the battery cell, The heat coefficient of the main reaction, This refers to the main reaction heating power of the battery cell.

[0078] A feasible formula for calculating the heating power of side reactions is as follows:

[0079]

[0080] In the formula, This is the cell's secondary reaction current. This refers to the cell terminal voltage. This refers to the heat generated by the side reactions of the battery cell.

[0081] A feasible formula for calculating entropy change heating power is as follows:

[0082]

[0083] In the formula, Represents the entropy change heating power. The current of the battery cell, The temperature of the battery cell, This is the open-circuit voltage corresponding to the current nuclear power state of the battery cell.

[0084] A feasible formula for calculating the heat generation power of electrical components and contact internal resistance due to electrical connections is as follows:

[0085]

[0086] In the formula, This refers to the heat generated by the electrical connections and the internal resistance of the electrical components and contacts. The current of the battery cell, It is the sum of the internal resistance and contact resistance of the electrical components.

[0087] It should be noted that this application provides an exemplary method for calculating the main reaction heating power, secondary reaction heating power, entropy change heating power, and heating power caused by electrical connection of the battery cell. Calculating the main reaction heating power, secondary reaction heating power, entropy change heating power, and heating power caused by electrical connection of the battery cell through other methods is also within the scope of protection of this application.

[0088] S303: If the battery system reaches thermal steady state, the increase in the internal energy of the cell is 0, and the heat transfer power of the cell is equal to the heat generation power of the cell.

[0089] The heating power of a battery cell can be divided into two parts: the power of internal energy increase and the power of heat transfer. When the battery system reaches thermal steady state, the temperature of the cell no longer changes, the internal energy of the cell no longer increases, the increase in internal energy is 0, and the power of internal energy increase is 0. Therefore, the heat transfer power of the cell is equal to the heating power of the cell.

[0090] S304: If the battery system has not reached thermal steady state, determine the increase in internal energy of the cell based on the increase in internal energy of the cell and the time it takes for the cell temperature to change; determine the heat transfer power of the cell based on the heat generation power of the cell and the increase in internal energy of the cell.

[0091] When the battery system has not reached thermal steady state, the cell temperature gradually increases, and the cell's internal energy also increases accordingly. Optionally, the increase in the cell's internal energy can be calculated by dividing the increase in the cell's internal energy by the time it takes for the cell temperature to change.

[0092] In one implementation scenario, the difference between the heating power of the battery cell and the increase in the internal energy of the battery cell can be used as the heat transfer power of the battery cell.

[0093] S305: Determine the heat transfer power between the battery cell and any area in contact with the battery cell based on the ratio of the temperature of the battery cell and the temperature difference between any area in contact with the battery cell to the sum of the temperature differences between the battery cell and all areas in contact with the battery cell, and the heat transfer power of the battery cell.

[0094] Any area in contact with the battery cell can be a single battery cell, a collection of battery cells and other components within any continuous area, or the external environment.

[0095] When a battery cell comes into contact with multiple regions, the distribution of heat transfer power is directly proportional to the temperature difference between the battery cell and the regions in contact with it. The formula for calculating the heat transfer power between the battery cell and any region in contact with it can be as follows:

[0096]

[0097] In the formula, i represents the battery cell, j represents any region in contact with the battery cell, and n represents all regions in contact with the battery cell. The heat transfer power between i and j Indicates the average temperature of i. This represents the average temperature of j. This refers to the heating power of the battery cell. To increase the internal energy of the battery cell, This represents the time it takes for the cell temperature to change.

[0098] Because heat transfer occurs from the high-temperature region to the low-temperature region. When When the value is greater than 0, it indicates that heat is transferred from i to j; when When the value is less than 0, it indicates that heat is transferred from j to i.

[0099] In one implementation scenario, when the battery system is in a thermal steady state, the increase in the internal energy of the battery cell is... is 0.

[0100] S306: Determine the heat transfer coefficient between the battery cell and any area in contact with the battery cell based on the heat transfer power between the battery cell and any area in contact with the battery cell, the contact area, the temperature of the battery cell and the temperature of any area in contact with the battery cell.

[0101] Since the heat transfer coefficient is the amount of heat transferred per unit area per unit time, it is related to the size of the contact area between the battery cell and any region in contact with the cell. For a given amount of heat transferred, the larger the contact area, the smaller the heat transfer coefficient.

[0102] This application provides a method for obtaining the heat transfer coefficient of a battery system. It receives data from a battery management system, including the temperature, current, voltage, and time of temperature change of the battery cells. The method determines the heating power of the battery cell based on its current and voltage, the temperature change based on its temperature, and the increase in internal energy based on the temperature change. When the battery system is in a thermally stable state, the temperature of the battery cell does not change, and its internal energy increase is zero; at this time, the heat transfer power of the battery cell is equal to its heating power. When the battery system is not in a thermally stable state, the increase in internal energy of the battery cell can be determined based on the increase in internal energy and the time of temperature change. The heat transfer power of the battery cell is determined based on the increase in internal energy and the heating power. Since the distribution of heat transfer power is proportional to the temperature difference between the battery cell and the area in contact with it, the heat transfer power between the battery cell and any area in contact with it can be determined based on the ratio of the temperature difference between the battery cell and any area in contact with it to the sum of the temperature differences between the battery cell and all areas in contact with it, and the heat transfer power of the battery cell. The heat transfer coefficient between the battery cell and any region in contact with it is determined based on the heat transfer power and contact area, the temperature of the battery cell and the temperature of any region in contact with it. Whether the battery system is in a thermally steady state or not, the method provided in this application can calculate the heating power, increase in internal energy, and heat transfer power of the battery cell using the cell's current, voltage, temperature, and the time of temperature change. It can also determine the heat transfer coefficient of a single battery cell, a collection of multiple consecutive cells, and the battery system as a whole. This eliminates the need for a finite element model, reduces computational complexity, and improves computational efficiency.

[0103] Based on the above embodiments, the following provides a specific embodiment, taking a new energy vehicle battery pack as an example, to describe in detail the process of obtaining the heat transfer coefficient of the battery pack and the battery modules within the battery pack.

[0104] Figure 4 A flowchart illustrating a method for obtaining the heat transfer coefficient of a new energy vehicle battery module, as provided in this application embodiment, is shown below. Figure 4 As shown, the specific method is as follows:

[0105] S401: Receives the battery module temperature, current, and time of temperature change reported by the battery management system.

[0106] Figure 5This is a top view schematic diagram of a new energy vehicle battery pack provided in an embodiment of this application. In the figure, thick outlines represent the battery pack, thin outlines represent battery modules, and numbers represent the module numbers corresponding to the battery modules. The battery pack in the figure consists of 27 identical battery modules. Thermal insulation material is filled between the battery modules and between the battery modules and the outer casing of the battery pack. The battery pack has a single-layer structure, and there is no stacking of battery modules. Each battery module is a cubic structure with a total surface area of ​​6 Å and a temperature sampling point.

[0107] In one implementation scenario, the battery pack is initially in thermal equilibrium, and the temperature of all battery modules inside is equal to the ambient temperature T0.

[0108] During operation, the internal temperature of the battery pack rises, and the battery management system collects the temperature of each battery module. The temperature of battery module 1 is recorded as T1, the temperature of battery module 2 as T2, and so on, with the temperature of battery module i recorded as T... i .

[0109] S402: Determine the heating power of the battery module based on the current of the battery module, determine the temperature change of the battery module based on the temperature of the battery module, and determine the increase in internal energy of the battery module based on the temperature change of the battery module.

[0110] During the power throughput process of the battery pack, the battery modules generate heat. Assume that the heat generation power of each battery module is P.

[0111] A feasible formula for calculating the heat generation power of a battery module is as follows:

[0112]

[0113] In the formula, the subscript mod represents the battery module. This represents the current flowing through the battery module. This represents the total internal resistance of the battery module. This refers to the heat dissipation power of the battery module.

[0114] For battery module #i, the increase in its internal energy can be calculated using the following formula:

[0115]

[0116] In the formula, The increase in internal energy of battery module i. For the specific heat capacity of the battery module, Indicates the quality of the battery module. This is the current temperature of battery module i. This is the initial temperature of battery module i.

[0117] For example, such as Figure 5 As shown, battery module 14 is in contact with battery modules 5, 13, 15, and 23, and also with the top and bottom surfaces of the battery pack. The following is a detailed description using the determination of the heat transfer coefficient between battery module 14 and battery module 5 as an example.

[0118] In one implementation scenario, when the battery pack reaches thermal steady state, the increase in internal energy of battery module 14 is 0.

[0119] In another implementation scenario, when the battery pack has not yet reached thermal steady state, the increase in internal energy of battery module 14 can be calculated using the following formula:

[0120]

[0121] In the formula, The increase in internal energy of battery module No. 14 For the specific heat capacity of the battery module, Indicates the quality of the battery module. This is the current temperature of battery module #14. This is the initial temperature of battery module number 14.

[0122] S403: Determine the heat transfer power of the battery module based on the heat generation power, the increase in internal energy, and the time it takes for the battery module temperature to change.

[0123] In one implementation scenario, when the battery pack reaches thermal steady state, the heat dissipation power of each battery module is P. Due to the different locations of the battery modules, their temperatures will vary. Typically, the battery modules located at the center of the battery pack have higher temperatures, while those at the perimeter have lower temperatures. Because of the temperature difference between the battery modules, heat transfer occurs between them. Since the battery pack has reached thermal steady state, the internal energy increase of battery module 14 is 0, and the heat transfer power and heat dissipation power of battery module 14 are equal, both being P.

[0124] In another implementation scenario, when the battery pack has not yet reached thermal steady state, the heat dissipation power of each battery module is P. Understandably, there is a temperature difference between the battery modules, thus heat transfer occurs.

[0125] For example, the temperature of battery module No. 14 rises from T0 to T 14 The required time is The increase in power from the internal energy of battery module 14 can be calculated using the following formula:

[0126]

[0127] In the formula, This represents an increase in power from the internal energy of battery module #14. The increase in internal energy of battery module No. 14 The temperature of battery module No. 14 is determined by Rise to The time required.

[0128] Based on the heat output power P of battery module 14 and the increase in power from the internal energy of battery module 14 The heat transfer power of battery module 14 can be calculated using the following formula:

[0129]

[0130] In the formula, This refers to the heat transfer power of battery module No. 14. This refers to the heat dissipation power of battery module No. 14. To increase the power of the battery module's internal energy.

[0131] S404: Determine the heat transfer power between the battery module and any area in contact with the battery module based on the heat transfer power of the battery module, the temperature of the battery module, and the temperature of any area in contact with the battery module.

[0132] Any area in contact with the battery module can be a single battery module, multiple battery modules within any continuous area, or the external environment. The distribution of heat transfer power is proportional to the temperature difference between the battery module and the area in contact with it.

[0133] Depend on Figure 5 It is known that battery module 5 is in contact with battery module 14. In one implementation scenario, when the battery pack reaches thermal steady state, the heat transfer power between battery module 14 and battery module 5 can be calculated using the following formula:

[0134]

[0135] In the formula, This refers to the heat transfer power between battery module 14 and battery module 5. This refers to the heat transfer power of battery module No. 14. , , , , These represent the temperatures of battery modules No. 5, No. 13, No. 14, No. 15, and No. 23, respectively. This represents the ambient temperature.

[0136] In another implementation scenario, when the battery pack has not yet reached thermal steady state, the heat transfer power between battery module 14 and battery module 5 can be calculated using the following formula:

[0137]

[0138] In the formula, This refers to the heat transfer power between battery module 14 and battery module 5. This refers to the heat transfer power of battery module No. 14. , , , , These represent the temperatures of battery modules No. 5, No. 13, No. 14, No. 15, and No. 23, respectively. This represents the ambient temperature.

[0139] S405: Determine the heat transfer coefficient between the battery module and any area in contact with the battery module based on the heat transfer power between the battery module and any area in contact with the battery module, the contact area, the temperature of the battery module and the temperature of any area in contact with the battery module.

[0140] Taking battery module 14 and battery module 5 as examples, the contact area between them is A. Therefore, the formula for calculating the heat transfer coefficient between battery module 14 and battery module 5 can be as follows:

[0141]

[0142] In the formula, The heat transfer coefficient between battery module 14 and battery module 5. This refers to the heat transfer power between battery module 14 and battery module 5. This represents the contact area between battery module 14 and battery module 5. and These represent the temperatures of battery module 5 and battery module 14, respectively.

[0143] In another implementation scenario, the heat transfer coefficients of multiple consecutive battery modules can also be solved. For example, battery modules 14, 15, 23, and 24 can be considered as a single unit, such as... Figure 5 As shown, this part contacts battery modules 5, 6, 13, 16, 22, and 25 with area A, contacts the side of the battery pack with area 2A, and contacts the top and bottom surfaces of the battery pack with area 4A. The overall heat transfer coefficient of this part can be calculated using the following formula:

[0144]

[0145] In the formula, This represents the overall heat transfer coefficient of battery modules 14, 15, 23, and 24. The heat transfer coefficients of battery modules No. 14 and No. 5 are given. The heat transfer coefficients of battery modules No. 14 and No. 13 are given. The heat transfer coefficients of battery modules No. 15 and No. 6 are given. The heat transfer coefficients of battery modules No. 15 and No. 16 are given. The heat transfer coefficients of battery modules No. 23 and No. 22 are given. The heat transfer coefficients for battery modules No. 24 and No. 25 are given. , , , These represent the heat transfer coefficients between battery modules No. 14, No. 15, No. 23, and No. 24 and the external environment, respectively.

[0146] Similarly, the entire battery pack can be considered as a whole, and the heat transfer coefficient of the entire battery pack to the outside can be solved using the above method.

[0147] It should be noted that the heat transfer coefficients under different conditions, such as when the vehicle is stationary, in motion, with the liquid cooling unit on, or with the liquid cooling unit off, can all be calculated using the above method.

[0148] In this application, the battery module's quality, specific heat capacity, internal resistance, and other related parameters can be tested in advance, or data provided by the cell supplier can be used.

[0149] This application provides a method for obtaining the heat transfer coefficient of a new energy battery module. It receives the battery module's temperature, current, and the time it takes for the battery module's temperature to change, reported by the battery management system. The method determines the battery module's heating power based on the current, the temperature change based on the temperature, and the increase in internal energy based on the temperature change. Furthermore, it determines the battery module's heat transfer power based on the heating power, the increase in internal energy, and the time it takes for the battery module's temperature to change. Based on the battery module's heat transfer power, temperature, and the temperature of any area in contact with the battery module, the method determines the heat transfer power between the battery module and any area in contact with it. Finally, based on the heat transfer power between the battery module and any area in contact with it, the contact area, the temperature of the battery module, and the temperature of any area in contact with it, the method determines the heat transfer coefficient between the battery module and any area in contact with it. The method for obtaining the heat transfer coefficient of a battery module provided in this application calculates the heat generation power, increase in internal energy, and heat transfer power of the battery module based on the current, temperature, and time of temperature change of the battery module to determine the heat transfer coefficient of the battery module. It can also calculate the heat transfer coefficient of multiple consecutive battery modules and the entire battery pack in any region. It does not require the establishment of a finite element model, has a small amount of calculation, and improves calculation efficiency.

[0150] Figure 6 A schematic diagram of a battery system heat transfer coefficient acquisition device provided in this application embodiment. Figure 1 .like Figure 6 As shown in the figure, this application embodiment provides a battery system heat transfer coefficient acquisition device 600, which may include a receiving module 601 and a determining module 602.

[0151] Receiver module 601 is used to receive the temperature, current and time of change of cell temperature in the battery system reported by the battery management system.

[0152] The determining module 602 is used to determine the heating power of the battery cell based on the current and voltage of the battery cell, determine the temperature change of the battery cell based on the temperature of the battery cell, and determine the increase in internal energy of the battery cell based on the temperature change of the battery cell.

[0153] The determining module 602 is also used to determine the heat transfer power of the battery cell based on the heating power of the battery cell, the increase in the internal energy of the battery cell, and the time it takes for the battery cell temperature to change.

[0154] The determining module 602 is further configured to determine the heat transfer power between the battery cell and any area in contact with the battery cell based on the heat transfer power of the battery cell, the temperature of the battery cell, and the temperature of any area in contact with the battery cell.

[0155] The determining module 602 is further configured to determine the heat transfer coefficient between the battery cell and any region in contact with the battery cell based on the heat transfer power between the battery cell and any region in contact with the battery cell, the contact area, the temperature of the battery cell and the temperature of any region in contact with the battery cell.

[0156] The device in this embodiment can be used to perform, for example... Figure 2 The method embodiments shown are similar in principle and technical effect, and will not be described again here.

[0157] Figure 7 A schematic diagram of a battery system heat transfer coefficient acquisition device provided in this application embodiment. Figure 2 .like Figure 7 As shown in the figure, this application embodiment provides a battery system heat transfer coefficient acquisition device 700, which includes a processor 701 and a memory 702, wherein the processor 701 and the memory 702 are connected through a bus 703.

[0158] In the specific implementation process, the memory 702 stores code, and the processor 701 runs the code stored in the memory 702 to execute the battery system heat transfer coefficient acquisition method of the above method embodiment.

[0159] The specific implementation process of processor 701 can be found in the above method embodiments, and its implementation principle and technical effect are similar. It will not be repeated here.

[0160] In the above Figure 7 In the illustrated embodiments, it should be understood that the processor 701 can be a Central Processing Unit (CPU), or other general-purpose processors, digital signal processors (DSPs), application-specific integrated circuits (ASICs), etc. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the method disclosed in this invention can be directly implemented by a hardware processor, or implemented by a combination of hardware and software modules within the processor.

[0161] The memory 702 may include high-speed RAM memory, and may also include non-volatile memory NVM, such as at least one disk storage.

[0162] Bus 703 can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Bus 703 can be divided into address bus, data bus, control bus, etc. For ease of illustration, the bus 703 in the accompanying drawings of this application is not limited to only one bus or one type of bus.

[0163] This application provides a computer-readable storage medium storing computer-executable instructions. When executed by a processor, these instructions are used to implement the battery system heat transfer coefficient acquisition method described in the above method embodiments.

[0164] The aforementioned computer-readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk. The readable storage medium can be any available medium accessible to a general-purpose or special-purpose computer.

[0165] An exemplary readable storage medium is coupled to a processor, enabling the processor to read information from and write information to the readable storage medium. Of course, the readable storage medium can also be a component of the processor. The processor and the readable storage medium can reside in an Application Specific Integrated Circuit (ASIC). Alternatively, the processor and the readable storage medium can exist as discrete components in the device.

[0166] This application provides a computer program product, including a computer program that, when executed by a processor, implements the battery system heat transfer coefficient acquisition method provided in any of the embodiments of this application.

[0167] Other embodiments of this application will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this application that follow the general principles of this application and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this application are indicated by the following claims.

[0168] It should be understood that the present application is not limited to the exact structure described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof. The scope of the present application is limited only by the appended claims.

Claims

1. A method for obtaining the heat transfer coefficient of a battery system, characterized in that, include: Receive data from the battery management system, including the temperature, current, voltage of the cells in the battery system, and the time when the cell temperature changes. The heating power of the battery cell is determined based on the current and voltage of the battery cell, the temperature change of the battery cell is determined based on the temperature of the battery cell, and the increase in internal energy of the battery cell is determined based on the temperature change of the battery cell. The heat transfer power of the battery cell is determined based on the heating power of the battery cell, the increase in the internal energy of the battery cell, and the time it takes for the battery cell temperature to change. The heat transfer power between the battery cell and any region in contact with the battery cell is determined based on the heat transfer power of the battery cell, the temperature of the battery cell, and the ratio of the temperature difference of any region in contact with the battery cell to the sum of the temperature differences between the battery cell and all regions in contact with the battery cell. The heat transfer coefficient between the battery cell and any region in contact with the battery cell is determined based on the heat transfer power and contact area between the battery cell and any region in contact with the battery cell, the temperature of the battery cell and the temperature of any region in contact with the battery cell.

2. The method according to claim 1, characterized in that, Determining the heat transfer power of the battery cell based on its heating power, the increase in its internal energy, and the time it takes for its temperature to change includes: If the battery system reaches thermal steady state, the increase in the internal energy of the cell is 0, and the heat transfer power of the cell is equal to the heat generation power of the cell.

3. The method according to claim 2, characterized in that, The step of determining the heat transfer power of the battery cell based on the heating power of the battery cell, the increase in the internal energy of the battery cell, and the time it takes for the battery cell temperature to change further includes: If the battery system has not reached thermal steady state, the increase in internal energy of the cell is determined based on the increase in internal energy of the cell and the time it takes for the cell temperature to change. The heat transfer power of the battery cell is determined based on the heating power of the battery cell and the increase in internal energy of the battery cell.

4. The method according to claim 1, characterized in that, The heating power of the battery cell includes one or more of the following: heating power of the main reaction, heating power of the side reaction, heating power of entropy change, and heating power caused by electrical connection.

5. The method according to claim 4, characterized in that, The battery cell is a single battery cell or a packaged collection of multiple consecutive battery cells.

6. A device for obtaining the heat transfer coefficient of a battery system, characterized in that, include: The receiving module is used to receive the temperature and current of the cells in the battery system, as well as the time when the temperature of the cells changes, reported by the battery management system. The determination module is used to determine the heating power of the battery cell based on the current and voltage of the battery cell, determine the temperature change of the battery cell based on the temperature of the battery cell, and determine the increase in internal energy of the battery cell based on the temperature change of the battery cell. The determining module is further configured to determine the heat transfer power of the battery cell based on the heating power of the battery cell, the increase in the internal energy of the battery cell, and the time it takes for the temperature of the battery cell to change. The determining module is further configured to determine the heat transfer power between the battery cell and any region in contact with the battery cell based on the heat transfer power of the battery cell, the temperature of the battery cell, and the ratio of the temperature difference of any region in contact with the battery cell to the sum of the temperature differences between the battery cell and all regions in contact with the battery cell. The determining module is further configured to determine the heat transfer coefficient between the battery cell and any region in contact with the battery cell based on the heat transfer power and contact area between the battery cell and any region in contact with the battery cell, the temperature of the battery cell and the temperature of any region in contact with the battery cell.

7. A battery system heat transfer system acquisition device, comprising: A processor and a memory, wherein code is stored in the memory, and the processor executes the code stored in the memory to perform the battery system heat transfer system acquisition method as described in any one of claims 1-5.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer-executable instructions, which, when executed by a processor, are used to implement the battery system heat transfer system acquisition method as described in any one of claims 1-5.

9. A computer program product comprising a computer program that, when executed by a processor, implements the battery system heat transfer system acquisition method according to any one of claims 1-5.

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