Thermal runaway simulation method, apparatus, and program product

Abstract

The present disclosure relates to a heat spread simulation method, device and program product, and relates to the technical field of battery simulation. The heat spread simulation method comprises: dividing a first cell in a battery model into a plurality of first sub-cells, wherein a second cell is located on one side of the first cell, a heating plate is located on the other side of the first cell, and the plurality of first sub-cells are sequentially arranged in the direction from the heating plate to the first cell; heating the first cell based on the heating plate until the temperature of the last first sub-cell reaches the thermal runaway temperature of the first cell; for each first sub-cell, determining the heat generation power of the first sub-cell according to a first relationship between the temperature of the first sub-cell and the thermal runaway temperature; determining the temperature of the second cell in a period when the first cell occurs thermal runaway according to the heat generation power of each first sub-cell; and determining a risk level of heat spread according to the temperature of the second cell in the period.

Description

Technical Field

[0001] This disclosure relates to the field of battery simulation technology, and in particular to a thermal propagation simulation method, apparatus and program product. Background Technology

[0002] With the rapid development of new energy vehicles and energy storage technologies, lithium-ion batteries have become the most widely used energy storage devices due to their high energy density and long cycle life. However, lithium-ion batteries have inherent safety hazards. Under conditions such as overcharging, over-discharging, puncture, compression, and high-temperature abuse, they are prone to thermal runaway of individual battery cells, generating a large amount of heat. Summary of the Invention

[0003] One of the technical problems this disclosure aims to solve is how to accurately predict the risk of thermal propagation triggered by a specified battery cell in the event of thermal runaway.

[0004] According to some embodiments of the first aspect of this disclosure, a thermal propagation simulation method is provided, comprising: dividing a first cell in a battery model into multiple first sub-cells, wherein a second cell is located on one side of the first cell, a heating plate is located on the other side of the first cell, and the multiple first sub-cells are arranged sequentially in the direction from the heating plate to the first cell; heating the first cell based on the heating plate until the temperature of the last first sub-cell reaches the thermal runaway temperature of the first cell; for each first sub-cell, determining the heat generation power of the first sub-cell based on a first relationship between the temperature of the first sub-cell and the thermal runaway temperature; determining the temperature of the second cell during the period in which the first cell experiences thermal runaway based on the heat generation power of each first sub-cell; and determining the risk level of thermal propagation based on the temperature of the second cell during the period.

[0005] In some embodiments, determining the heat generation power of the first sub-cell based on a first relationship between the temperature of the first sub-cell and the thermal runaway temperature includes: determining the heat generation power of the first sub-cell based on the first relationship, the heat generation power curve of the first cell, and the duration of the time period during which the temperature of the first sub-cell is first greater than the thermal runaway temperature.

[0006] In some embodiments, the thermal propagation simulation method further includes: using an adiabatic accelerated calorimeter to perform a thermal runaway test on a third battery cell, and determining a second relationship between the thermal runaway temperature and the temperature and time of the first battery cell, wherein the third battery cell is a battery cell with the same specifications as the first battery cell, and the second relationship is the correspondence between the temperature and time of the first battery cell when it is in thermal runaway; and determining the heat generation power curve of the first battery cell based on the second relationship.

[0007] In some embodiments, determining the heat generation power curve of the first battery cell according to the second relationship includes: determining the heat generation power curve of the first battery cell according to the second relationship, the specific heat capacity of the first battery cell, and the mass of the first battery cell.

[0008] In some embodiments, determining the heat generation power of the first sub-cell based on the first relationship, the heat generation power curve of the first cell, and the duration of the time period during which the temperature of the first sub-cell first exceeds the thermal runaway temperature includes: determining whether the first sub-cell is in thermal runaway based on the first relationship and the duration; and determining the heat generation power of the first sub-cell based on the duration and the heat generation power curve of the first cell when the first sub-cell is in thermal runaway.

[0009] In some embodiments, determining whether the first sub-cell is in thermal runaway based on the first relationship and duration includes: determining that the first sub-cell is in thermal runaway when the temperature of the first sub-cell is greater than the thermal runaway temperature for the first time and the duration is less than a time threshold; determining that the first sub-cell is not in thermal runaway when the temperature of the first sub-cell is less than or equal to the thermal runaway temperature and there is no instance where the temperature of the first sub-cell is greater than the thermal runaway temperature; and determining that the first sub-cell is not in thermal runaway when the duration is greater than or equal to the time threshold.

[0010] In some embodiments, determining the heat generation power of the first sub-cell based on the first relationship, the heat generation power curve of the first cell, and the duration of the time period during which the temperature of the first sub-cell first exceeds the thermal runaway temperature further includes: determining that the heat generation power of the first sub-cell is zero when the first sub-cell is not in thermal runaway.

[0011] In some embodiments, determining the temperature of the second cell within the period in which the first cell experiences thermal runaway, based on the heat generation power of each first sub-cell, includes: for each first sub-cell, within the period, determining the current temperature of the first sub-cell based on the heat generation power of the first sub-cell at the previous moment, the temperature of the first sub-cell at the previous moment, the temperature of the second sub-cell at the previous moment, and the ambient temperature corresponding to the first cell at the previous moment, wherein, if the first sub-cell is not the last first sub-cell, the second sub-cell is the first sub-cell adjacent to the first sub-cell; if the first sub-cell is the last first sub-cell, the second sub-cell is the first sub-cell adjacent to the first sub-cell and the second cell; and determining the temperature of the second cell at the next moment within the period based on the current temperature of the last first sub-cell.

[0012] In some embodiments, determining the current temperature of the first sub-cell based on the heat generation power of the first sub-cell at the previous moment, the temperature of the first sub-cell at the previous moment, the temperature of the second sub-cell at the previous moment, and the ambient temperature corresponding to the first cell at the previous moment includes: determining a first heat transfer between the first sub-cell and the second sub-cell based on the temperatures of the first sub-cell and the second sub-cell at the previous moment; determining a second heat transfer between the first sub-cell and the environment corresponding to the first cell based on the temperature of the first sub-cell at the previous moment and the ambient temperature corresponding to the first cell at the previous moment; determining a third heat generated by the first sub-cell based on the heat generation power of the first sub-cell at the previous moment; and determining the current temperature of the first sub-cell based on the temperature of the first sub-cell at the previous moment, the first heat transfer, the second heat transfer, and the third heat transfer.

[0013] In some embodiments, determining the temperature of the second cell at the next moment within a cycle based on the current temperature of the last first cell includes: determining the temperature of the second cell at the next moment based on the current temperature of the last first cell, the current temperature of the second cell, and the ambient temperature corresponding to the first cell at the current moment.

[0014] In some embodiments, determining the risk level of heat spread based on the temperature of the second cell during the cycle includes: determining the highest temperature and average temperature of the second cell during the cycle; if the highest temperature of the second cell is less than a temperature threshold, determining the risk level of heat spread as a first level; if the highest temperature of the second cell is greater than or equal to the temperature threshold, determining the risk level of heat spread as a second level; and if the average temperature of the second cell is greater than or equal to the temperature threshold, determining the risk level of heat spread as a third level, wherein the first level is lower than the second level, and the second level is lower than the third level.

[0015] In some embodiments, the period during which the first cell experiences thermal runaway is the time period from when the last first sub-cell begins to experience thermal runaway until the last first sub-cell ends to experience thermal runaway.

[0016] According to some embodiments of the second aspect of this disclosure, a thermal propagation simulation device is provided, comprising: a partitioning unit configured to partition a first cell in a battery model into a plurality of first sub-cells, wherein a second cell is located on one side of the first cell, a heating plate is located on the other side of the first cell, and the plurality of first sub-cells are arranged sequentially in the direction from the heating plate to the first cell; a heating unit configured to heat the first cell based on the heating plate until the temperature of the last first sub-cell reaches the thermal runaway temperature of the first cell; a first determining unit configured to determine, for each first sub-cell, the heat generation power of the first sub-cell based on a first relationship between the temperature of the first sub-cell and the thermal runaway temperature; a second determining unit configured to determine, based on the heat generation power of each first sub-cell, the temperature of the second cell during a period in which the first cell experiences thermal runaway; and a third determining unit configured to determine a risk level of thermal propagation based on the temperature of the second cell during the period.

[0017] In some embodiments, according to some embodiments of the third aspect of this disclosure, a thermal propagation simulation apparatus is provided, comprising: a memory and a processor coupled to the memory, the processor being configured to execute the thermal propagation simulation method of any of the above embodiments based on instructions stored in the memory.

[0018] According to some embodiments of the fourth aspect of this disclosure, a computer-readable storage medium is provided having computer instructions stored thereon that, when executed by a processor, implement the thermal propagation simulation method of any of the above embodiments.

[0019] According to some embodiments of the fifth aspect of this disclosure, a computer program product is provided, including computer instructions that, when executed by a processor, implement the thermal propagation simulation method of any of the above embodiments.

[0020] In the above embodiments, by dividing the first cell and placing a second cell on one side of the first cell and a heating plate on the other side of the first cell, the simulation of thermal runaway of the cell takes into account the characteristics of unilateral heating of the cell and the development of thermal runaway from local to global, which can improve the accuracy of thermal runaway simulation and thus improve the accuracy of predicting the risk of thermal propagation. Furthermore, by determining the temperature of the second cell during the thermal runaway period of the first cell based on the heat generation power of each first sub-cell, the risk of thermal propagation can be determined based on the temperature of the second cell. In determining the temperature of the second cell, the fact that each first sub-cell generates heat when in a thermal runaway state, and that this heat affects the temperature of the second cell, is taken into account, improving the accuracy of determining the temperature of the second cell and thus improving the accuracy of predicting the risk of thermal propagation. In addition, the above embodiments provide a universal thermal propagation simulation method, reducing the risk of being limited to a single simulation software. Attached Figure Description

[0021] The accompanying drawings, which form part of this specification, illustrate embodiments of this disclosure and, together with the specification, serve to explain the principles of this disclosure.

[0022] This disclosure can be more clearly understood with reference to the accompanying drawings and the following detailed description.

[0023] Figure 1 Schematic diagrams illustrating some embodiments of the thermal propagation simulation method of this disclosure are shown.

[0024] Figure 2 Schematic diagrams illustrating some embodiments of the three-dimensional heat transfer model of this disclosure are shown.

[0025] Figure 3 Schematic diagrams illustrating some application examples of the method for determining the heat generation power of the first sub-cell according to this disclosure.

[0026] Figure 4 Schematic diagrams illustrating some other application examples of the method for determining the heat generation power of the first sub-cell of this disclosure.

[0027] Figure 5 Schematic diagrams illustrating further applications of the method for determining the heat generation power of the first sub-cell of this disclosure.

[0028] Figure 6 Schematic diagrams showing some embodiments of the heat generation power curve of the first cell of this disclosure.

[0029] Figure 7 Schematic diagrams of some embodiments illustrating simulation results of the temperature of each first sub-cell and the temperature of the second cell of this disclosure.

[0030] Figure 8 Schematic diagrams illustrating some other embodiments of the thermal propagation simulation method of this disclosure are shown.

[0031] Figure 9 Schematic diagrams of some embodiments of the thermal propagation simulation apparatus of this disclosure are shown.

[0032] Figure 10 Schematic diagrams of other embodiments of the thermal propagation simulation apparatus of this disclosure are shown.

[0033] Figure 11 Schematic diagrams showing further embodiments of the thermal propagation simulation apparatus of this disclosure are provided. Detailed Implementation

[0034] Various exemplary embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present disclosure.

[0035] At the same time, it should be understood that, for ease of description, the dimensions of the various parts shown in the accompanying drawings are not drawn according to actual scale.

[0036] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this disclosure or its application or use.

[0037] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, they should be considered part of the specification.

[0038] In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0039] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0040] When a cell in a battery experiences thermal runaway, it generates a large amount of heat, which can trigger a chain reaction of thermal runaway in adjacent cells, resulting in thermal propagation across the entire battery pack. Thermal propagation refers to the phenomenon where a single cell experiences thermal runaway, transferring heat to an adjacent cell and causing that adjacent cell to also experience thermal runaway.

[0041] In the battery production process, different materials need to be configured between cells to achieve effective heat insulation. The above-mentioned thermal propagation simulation method can accurately predict the risk of triggering thermal propagation, providing technical support for determining whether the materials configured between cells are appropriate, and also providing technical support for the selection of configuration materials between cells in the battery production process.

[0042] Therefore, accurately predicting the risk of thermal propagation during battery cell activation is a problem that needs to be solved. To address this issue, this disclosure proposes a thermal propagation simulation method, as detailed below.

[0043] Figure 1 Schematic diagrams illustrating some embodiments of the thermal propagation simulation method of this disclosure are shown.

[0044] like Figure 1 As shown, the thermal propagation simulation method includes steps 110 to 150, wherein the thermal propagation simulation method is executed by a thermal propagation simulation device.

[0045] In step 110, the first cell in the battery model is divided into multiple first sub-cells, wherein the second cell is located on one side of the first cell, the heating plate is located on the other side of the first cell, and the multiple first sub-cells are arranged in order from the heating plate to the first cell.

[0046] For example, the division direction of the first cell is perpendicular to the heat transfer direction, the second cell located on one side of the first cell is the cell with heat spread risk, and the heating plate is located on the other side of the first cell, that is, heat is transferred from the heating plate to the second cell.

[0047] By dividing the first cell in a direction perpendicular to the heat transfer direction, the heat transfer situation of the cell in thermal runaway can be accurately simulated, which helps to improve the accuracy of heat propagation simulation.

[0048] For example, the second cell can be a complete cell or a portion of an adjacent cell located on the other side of the first cell, which is adjacent to the first cell.

[0049] In step 120, the first cell is heated based on the heating plate until the temperature of the last first sub-cell reaches the thermal runaway temperature of the first cell.

[0050] Thermal runaway temperature can be, for example, the temperature of the cell when the cell temperature rises at a rate of 1°C / min.

[0051] For example, to determine whether the temperature of the last first sub-cell has reached the thermal runaway temperature of the first cell, it is necessary to determine the temperature of the last first sub-cell in real time. The temperature of the last first sub-cell can be determined in real time by: determining the temperature of each first sub-cell in real time based on the heat transfer between adjacent first sub-cells and the heat transferred to the first first sub-cell by the heating plate, thereby determining the temperature of the last first sub-cell.

[0052] Assuming the first cell is divided into three first sub-cells, let's take the temperature of the first sub-cell as an example. Based on the temperature of the first sub-cell at the previous moment, the temperature of the second sub-cell at the previous moment, the ambient temperature at the previous moment, and the heat transferred to the first sub-cell by the heating plate at the current moment, the temperature of the first sub-cell at the current moment is determined.

[0053] Taking the determination of the temperature of the second first sub-cell as an example, the temperature of the second first sub-cell at the current moment is determined based on the temperature of the first first sub-cell at the previous moment, the temperature of the second first sub-cell at the previous moment, and the ambient temperature at the previous moment.

[0054] Taking the determination of the temperature of the last first sub-cell as an example, the temperature of the last first sub-cell at the current moment is determined based on the temperature of the second first sub-cell at the previous moment, the temperature of the last first sub-cell at the previous moment, the ambient temperature at the previous moment, and the temperature of the second cell at the previous moment.

[0055] A three-dimensional heat transfer model was constructed by dividing the first battery cell and deploying the heating plate. The following section combines this model with... Figure 2 Describe the constructed three-dimensional heat transfer model. Figure 2 Schematic diagrams illustrating some embodiments of the three-dimensional heat transfer model of this disclosure are shown.

[0056] like Figure 2 As shown, a heating plate 22 is provided on one side of the first battery cell 21, that is, the first battery cell 21 is on one side of the heating plate 22, and heat insulation cotton 23 is provided on the other side of the heating plate 22 to prevent the heating plate 22 from heating other battery cells.

[0057] The first battery cell 21 is divided into seven first sub-cells, namely first sub-cell C1, first sub-cell C2, first sub-cell C3, first sub-cell C4, first sub-cell C5, first sub-cell C6 and first sub-cell C7. These seven first sub-cells are arranged in order from the heating plate 22 to the first battery cell 21.

[0058] The three-dimensional heat transfer model includes 10 battery cells, with inter-cell material 24 placed between the cells. Inter-cell material is also placed between the first and second battery cells. For example, the inter-cell material is a material used for heat propagation protection, and can be aerogel, nanoplate, etc. The inter-cell material is not limited here.

[0059] exist Figure 2 In the middle, the second cell 25 is a part of the cell on the other side of the first cell.

[0060] like Figure 2 As shown, thermally conductive adhesive 26 is placed beneath all the battery cells in the three-dimensional heat transfer model, and a liquid cooling plate 27 is placed beneath the thermally conductive adhesive 26. The function of the thermally conductive adhesive 26 is to conduct heat, and the function of the liquid cooling plate 27 is to dissipate heat.

[0061] For example, the width of the first cell can be less than or equal to 3mm, and the width of the second cell (partial cell) can also be 3mm.

[0062] In step 130, for each first sub-cell, the heat generation power of the first sub-cell is determined according to the first relationship between the temperature of the first sub-cell and the thermal runaway temperature.

[0063] For example, the first relationship between the temperature of the first sub-cell and the thermal runaway temperature can be the magnitude relationship between the temperature of the first sub-cell and the thermal runaway temperature.

[0064] The heat generation power of the first sub-cell is used to indicate the amount of heat generated inside the first sub-cell per unit time.

[0065] In step 140, the temperature of the second cell during the period when the first cell experiences thermal runaway is determined based on the heat generation power of each first sub-cell.

[0066] For example, the period during which the first cell experiences thermal runaway is the time period from when the last first sub-cell begins to experience thermal runaway until the last first sub-cell ends to experience thermal runaway.

[0067] In step 150, the risk level of thermal propagation is determined based on the temperature of the second cell during the cycle.

[0068] In the above embodiments, by dividing the first cell and placing a second cell on one side of the first cell and a heating plate on the other side of the first cell, the simulation of thermal runaway of the cell takes into account the characteristics of unilateral heating of the cell and the development of thermal runaway from local to overall, which can improve the accuracy of thermal runaway simulation and thus improve the accuracy of predicting the risk of thermal propagation. Furthermore, by determining the temperature of the second cell during the thermal runaway period of the first cell based on the heat generation power of each first sub-cell, the risk of thermal propagation can be determined based on the temperature of the second cell. In determining the temperature of the second cell, the fact that each first sub-cell generates heat in a thermal runaway state, and that this heat affects the temperature of the second cell, is taken into account, improving the accuracy of determining the temperature of the second cell and thus improving the accuracy of predicting the risk of thermal propagation. This provides reliable technical support for subsequent prediction of the risk of thermal propagation in the battery pack or the design of materials between cells in the subsequent battery pack. In addition, the above embodiments provide a universal thermal propagation simulation method, reducing the risk of being limited to a single simulation software for thermal propagation simulation.

[0069] The following example describes how to determine the heat generation power of the first sub-cell.

[0070] In some embodiments, determining the heat generation power of the first sub-cell based on a first relationship between the temperature of the first sub-cell and the thermal runaway temperature includes: determining the heat generation power of the first sub-cell based on the first relationship, the heat generation power curve of the first cell, and the duration of the time period during which the temperature of the first sub-cell is first greater than the thermal runaway temperature.

[0071] When the temperature of the first sub-cell first exceeds the thermal runaway temperature, it indicates that the first sub-cell has started thermal runaway. The duration of the period when the temperature of the first sub-cell first exceeds the thermal runaway temperature refers to the duration during which the first sub-cell has started thermal runaway. This duration can, to some extent, indicate whether the first sub-cell has ended thermal runaway.

[0072] The above embodiments provide a method for determining the heat generation power of a first sub-cell. By combining the duration of the period during which the temperature of the first sub-cell first exceeds the thermal runaway temperature, the heat generation power of the first sub-cell is determined. This reduces the risk of incorrectly determining the heat generation power of the first sub-cell when it is no longer in thermal runaway, and helps to improve the accuracy of the heat generation power of the first sub-cell, thereby helping to improve the accuracy of thermal propagation simulation.

[0073] The following embodiments describe a specific method for determining the heat generation power of the first sub-telecommunication.

[0074] In some embodiments, determining the heat generation power of the first sub-cell based on the first relationship, the heat generation power curve of the first cell, and the duration of the time period during which the temperature of the first sub-cell first exceeds the thermal runaway temperature includes: determining whether the first sub-cell is in thermal runaway based on the first relationship and the duration; and determining the heat generation power of the first sub-cell based on the duration and the heat generation power curve of the first cell when the first sub-cell is in thermal runaway.

[0075] The determination of whether the first sub-cell is in thermal runaway is based on whether the temperature of the first sub-cell is higher than the thermal runaway temperature for the first time and the duration of the first sub-cell being higher than the thermal runaway temperature. If the first sub-cell is in thermal runaway, the temperature of the first sub-cell should be higher than the thermal runaway temperature for the first time, and the duration of the first sub-cell being higher than the thermal runaway temperature should be less than the time threshold.

[0076] When the first sub-cell is in thermal runaway, the expression for the heat generation power of the first sub-cell is as follows: Prsk2(t) = Prsk1(t) / n, where Prsk1(t) represents the heat generation power curve of the first cell, and n represents the number of the first sub-cells. Substituting the duration into t, the heat generation power of the first sub-cell can be obtained.

[0077] In some embodiments, determining the heat generation power of the first sub-cell based on the first relationship, the heat generation power curve of the first cell, and the duration of the time period during which the temperature of the first sub-cell first exceeds the thermal runaway temperature further includes: determining that the heat generation power of the first sub-cell is zero when the first sub-cell is not in thermal runaway.

[0078] If the first cell is not in thermal runaway, it will not generate heat.

[0079] In the above embodiments, it is first determined whether the first sub-cell is in thermal runaway. When the first sub-cell is in thermal runaway, the heat generation power of the first sub-cell is then determined. This reduces the amount of calculation required to determine the heat generation power of the first sub-cell and improves the accuracy of determining the heat generation power of the first sub-cell.

[0080] To determine whether the first sub-cell is in thermal runaway, the following embodiments describe how to determine whether the first sub-cell is in thermal runaway.

[0081] In some embodiments, determining whether the first sub-cell is in thermal runaway based on the first relationship and duration includes: determining that the first sub-cell is in thermal runaway when the temperature of the first sub-cell is greater than the thermal runaway temperature for the first time and the duration is less than a time threshold; determining that the first sub-cell is not in thermal runaway when the temperature of the first sub-cell is less than or equal to the thermal runaway temperature and there is no instance where the temperature of the first sub-cell is greater than the thermal runaway temperature; and determining that the first sub-cell is not in thermal runaway when the duration is greater than or equal to the time threshold.

[0082] The first sub-cell not being in thermal runaway includes the first sub-cell not having started thermal runaway, and also includes the first sub-cell ending thermal runaway.

[0083] For example, the time threshold is the duration of thermal runaway of a battery cell, and different battery cells can correspond to different durations of thermal runaway.

[0084] For example, if the temperature of the first sub-cell is not greater than the thermal runaway temperature for the first time, and the duration is greater than or equal to the time threshold, it is determined that the first sub-cell is not in thermal runaway.

[0085] In the above embodiments, the determination of whether the first sub-cell is in thermal runaway is based on two dimensions of information: the temperature of the first sub-cell and the duration of the first sub-cell being above the thermal runaway temperature for the first time. This reduces the risk of misjudging that the first sub-cell is in thermal runaway (i.e., it reduces the risk of misjudging that the first sub-cell is in thermal runaway due to the temperature of the first sub-cell being continuously higher than the thermal runaway temperature or the temperature of the first sub-cell being triggered twice (or multiple times after the first time)). This improves the accuracy of determining whether the first sub-cell is in thermal runaway.

[0086] The heat generation power of each first sub-cell is described in conjunction with the following two application examples.

[0087] Figure 3 Schematic diagrams illustrating some application examples of the method for determining the heat generation power of the first sub-cell according to this disclosure.

[0088] like Figure 3 As shown, the method for determining the heat generation power of the first sub-cell includes steps 301 to 309.

[0089] In step 301, the temperature of the first sub-cell at the current moment is obtained.

[0090] In step 302, it is determined whether the current temperature of the first sub-cell is greater than the thermal runaway temperature.

[0091] If the current temperature of the first sub-cell is greater than the thermal runaway temperature, then proceed to step 303; if the current temperature of the first sub-cell is less than or equal to the thermal runaway temperature, then proceed directly to step 306.

[0092] In step 303, it is determined whether the temperature of the first sub-cell at the previous moment is greater than the thermal runaway temperature.

[0093] If the temperature of the first sub-cell at the previous moment is greater than the thermal runaway temperature, then proceed directly to step 305; if the temperature of the first sub-cell at the previous moment is less than or equal to the thermal runaway temperature, then proceed to step 304.

[0094] In step 304, it is determined whether overheating runaway has been triggered.

[0095] If overheating runaway is triggered, proceed directly to step 306; otherwise, proceed to step 305.

[0096] In step 305, it is determined whether the duration for which the temperature of the first sub-cell is higher than the thermal runaway temperature is greater than or equal to a time threshold.

[0097] If the duration is greater than or equal to the time threshold, proceed to step 306; if the duration is less than the time threshold, proceed to step 307.

[0098] In step 306, it is determined that the first sub-cell is not in thermal runaway. Step 308 is then executed.

[0099] In step 307, it is determined that the first sub-cell is in thermal runaway. Step 309 is then executed.

[0100] In step 308, it is determined that the heat generation power of the first sub-cell is zero.

[0101] In step 309, the heat generation power of the first sub-cell is determined based on the aforementioned duration.

[0102] Figure 4 Schematic diagrams illustrating some other application examples of the method for determining the heat generation power of the first sub-cell of this disclosure.

[0103] like Figure 4 As shown, the method for determining the heat generation power of the first sub-cell includes steps 401 to 406.

[0104] In step 401, the temperature of the first sub-cell is obtained.

[0105] In step 402, it is determined whether the temperature of the first sub-cell is greater than the thermal runaway temperature.

[0106] If the temperature of the first sub-cell is greater than the thermal runaway temperature, proceed to step 403; if the temperature of the first sub-cell is less than or equal to the thermal runaway temperature, proceed directly to step 404.

[0107] In step 403, the first value is output, where the first value can be 1.

[0108] In step 404, a second value is output, which can be 0.

[0109] In step 405, the timing function is used to start timing when the received value changes from 0 to 1 and to stop timing when the received value changes from 1 to 0. Based on the timing result and the relationship between the timing result and the time threshold, the heat generation power of the first sub-cell is determined.

[0110] The timer stops until the received value changes from 0 to 1, or it continues until the received value changes from 1 to 0. If the received value changes from 0 to 1, the timer starts; if the received value changes from 1 to 0, the timer stops; if the received value changes from 0 to 1 again, the timer resumes, starting from the timer result before it stopped.

[0111] If the timing result is greater than or equal to the time threshold, the heat generation power of the first sub-cell is determined to be zero. If the timing result is less than the time threshold, the heat generation power of the first sub-cell is determined based on the timing result and the heat generation power curve of the first cell.

[0112] In step 406, the heat generation power of the first sub-cell is output.

[0113] Figure 5 Schematic diagrams illustrating further applications of the method for determining the heat generation power of the first sub-cell of this disclosure.

[0114] like Figure 5 As shown, assuming Figure 5 The curve in the figure represents the temperature change process of a certain first sub-cell. The thermal runaway temperature is 200℃, the time threshold is 160 seconds, and at 100 seconds, the temperature of the first sub-cell is 200.5℃.

[0115] Regarding the temperature change process 100 seconds ago, the temperature of the first sub-cell did not exceed the thermal runaway temperature, meaning the first sub-cell was not in thermal runaway, and therefore the heat generation power of the first sub-cell was zero.

[0116] For the temperature change process corresponding to 100 seconds, if the temperature of the first sub-cell exceeds the thermal runaway temperature, that is, the first sub-cell enters thermal runaway, then the heat generation power of the first sub-cell needs to be determined based on the heat generation power curve of the first cell and the duration of the first sub-cell's temperature exceeding the thermal runaway temperature.

[0117] For the temperature change process corresponding to 100 seconds to 260 seconds, if the temperature of the first sub-cell continuously exceeds the thermal runaway temperature, and the duration of the first sub-cell's temperature exceeding the thermal runaway temperature is less than the time threshold, then the heat generation power of the first sub-cell needs to be determined based on the heat generation power curve of the first cell and the duration of the first sub-cell's temperature exceeding the thermal runaway temperature.

[0118] For the temperature change process corresponding to 260 seconds to 300 seconds, the temperature of the first sub-cell continuously exceeds the thermal runaway temperature, but the duration of the first sub-cell's temperature exceeding the thermal runaway temperature is greater than or equal to the time threshold, that is, the first sub-cell has ended thermal runaway, and at this time the heat generation power of the first sub-cell is zero.

[0119] For the temperature change process corresponding to 300 to 400 seconds, if the temperature of the first sub-cell is lower than the thermal runaway temperature, and the time difference between this time and the time when the temperature of the first sub-cell first exceeds the thermal runaway temperature is greater than the time threshold, then the first sub-cell has ended thermal runaway, and the heat generation power of the first sub-cell is zero.

[0120] Regarding the temperature change process corresponding to 400 seconds, the temperature of the first sub-cell exceeds the thermal runaway temperature again. However, since this is not the first time the temperature of the first sub-cell has exceeded the thermal runaway temperature, and the time difference between this time and the time when the temperature of the first sub-cell first exceeds the thermal runaway temperature is greater than the time threshold, the first sub-cell has ended its thermal runaway. At this time, the heat generation power of the first sub-cell is zero.

[0121] For the temperature change process corresponding to 400 to 500 seconds, if the temperature of the first sub-cell exceeds the thermal runaway temperature for the first time, and the time difference between this time and the time when the temperature of the first sub-cell first exceeds the thermal runaway temperature is greater than the time threshold, then the first sub-cell has ended thermal runaway, and the heat generation power of the first sub-cell is zero.

[0122] Regarding the heat generation power curve of the first battery cell, the following embodiment describes how to determine the heat generation power curve of the first battery cell.

[0123] In some embodiments, an adiabatic accelerated calorimeter is used to perform a thermal runaway test on the third battery cell and determine a second relationship between the thermal runaway temperature and the temperature and time of the first battery cell, wherein the third battery cell is a battery cell with the same specifications as the first battery cell, and the second relationship is the correspondence between the temperature and time of the first battery cell when it is in thermal runaway; based on the second relationship, the heat generation power curve of the first battery cell is determined.

[0124] When the first cell is in thermal runaway, the heat generation power of the first cell at different times constitutes the heat generation power curve of the first cell.

[0125] Considering that the first cell is a virtual cell in the simulated battery model, the thermal runaway test is performed on a third cell (a physical cell) with the same specifications as the first cell. By conducting the thermal runaway test on the third cell, the thermal runaway temperature of the third cell and the relationship between the temperature and time of the third cell are obtained (this relationship is the correspondence between the temperature and time when the third cell is in thermal runaway). Finally, based on the thermal runaway temperature of the third cell, the thermal runaway temperature of the first cell is determined (for example, the thermal runaway temperature of the third cell is determined as the thermal runaway temperature of the first cell). Based on the relationship between the temperature and time of the third cell, a second relationship is determined (for example, the relationship between the temperature and time of the third cell is determined as the second relationship).

[0126] The above embodiments provide a method for determining the heat generation power curve of the first battery cell. By using an adiabatic accelerated calorimeter to perform thermal runaway testing on the third battery cell, the thermal runaway temperature and the temperature change law of the battery cell in thermal runaway over time (i.e., the second relationship) are determined. This provides a simple and accurate method for determining the heat generation power curve of the first battery cell.

[0127] The following embodiments describe how to determine the heat generation power curve of the first battery cell based on the second relationship.

[0128] In some embodiments, determining the heat generation power curve of the first battery cell according to the second relationship includes: determining the heat generation power curve of the first battery cell according to the second relationship, the specific heat capacity of the first battery cell, and the mass of the first battery cell.

[0129] The expression for the heat generation power of the first battery cell is as follows: Prsk1(t) = C × m × (df(t) / dt), where f(t) represents the function of the relationship between the temperature and time of the first battery cell in thermal runaway (the second relationship), C represents the specific heat capacity of the first battery cell, and m represents the mass of the first battery cell.

[0130] The above embodiments provide a specific method for determining the heat generation power curve of a first battery cell, which helps to obtain an accurate heat generation power curve.

[0131] Figure 6 Schematic diagrams illustrating some embodiments of the heat generation power curve of the first battery cell of this disclosure are shown. Among them, Figure 6 This is a schematic diagram of the heat generation power of the first battery cell. It is only used to illustrate the change in heat generation power when the first battery cell is in thermal runaway, and is not used to limit the actual heat generation power of the first battery cell in thermal runaway.

[0132] like Figure 6As shown, the horizontal axis represents time in seconds, and the vertical axis represents heat generation power in watts. Between 0 and 140 seconds, the first cell is in thermal runaway, and its heat generation power initially increases and then decreases. After 140 seconds, the first cell ends thermal runaway, and its heat generation power becomes zero.

[0133] After determining the heat generation power of each first sub-cell, it is necessary to determine the temperature of the second cell during the period when the first cell experiences thermal runaway, based on the heat generation power of each first sub-cell. This is so that the risk level of thermal propagation can be determined based on the temperature of the second cell during the period. The following embodiment describes how to determine the temperature of the second cell during the period when the first cell experiences thermal runaway.

[0134] In some embodiments, determining the temperature of the second cell within the period in which the first cell experiences thermal runaway, based on the heat generation power of each first sub-cell, includes: for each first sub-cell, within the period, determining the current temperature of the first sub-cell based on the heat generation power of the first sub-cell at the previous moment, the temperature of the first sub-cell at the previous moment, the temperature of the second sub-cell at the previous moment, and the ambient temperature corresponding to the first cell at the previous moment, wherein, if the first sub-cell is not the last first sub-cell, the second sub-cell is the first sub-cell adjacent to the first sub-cell; if the first sub-cell is the last first sub-cell, the second sub-cell is the first sub-cell adjacent to the first sub-cell and the second cell; and determining the temperature of the second cell at the next moment within the period based on the current temperature of the last first sub-cell.

[0135] For example, the heat generation power of the first sub-cell at the previous moment can be determined based on the temperature of the first sub-cell at the previous moment.

[0136] To determine the current temperature of each first sub-cell, let's assume the first cell is divided into three first sub-cells. Taking the determination of the current temperature of the first first sub-cell as an example, the temperature of the first first sub-cell at the previous moment is determined based on the heat generation power of the first first sub-cell at the previous moment, the temperature of the first first sub-cell at the previous moment, the temperature of the second first sub-cell at the previous moment, and the ambient temperature at the previous moment.

[0137] Taking the determination of the current temperature of the second first sub-cell as an example, the temperature of the second first sub-cell at the current moment is determined based on the temperature of the first first sub-cell at the previous moment, the heat generation power of the second first sub-cell at the previous moment, the temperature of the second first sub-cell at the previous moment, and the ambient temperature at the previous moment.

[0138] Taking the determination of the current temperature of the last first sub-cell as an example, the temperature of the last first sub-cell at the current moment is determined based on the temperature of the second first sub-cell at the previous moment, the heat generation power of the last first sub-cell at the previous moment, the temperature of the last first sub-cell at the previous moment, the ambient temperature at the previous moment, and the temperature of the second cell at the previous moment.

[0139] In the above embodiment, the current temperature of each first sub-cell is first determined so as to obtain the current temperature of the last first sub-cell. Then, based on the current temperature of the last first sub-cell, the temperature of the second cell at the next moment is determined. When determining the current temperature of each first sub-cell, the influence of adjacent sub-cells or the second cell, as well as the influence of ambient temperature, are taken into account, which improves the accuracy of determining the current temperature of each first sub-cell.

[0140] The method for determining the current temperature of each first sub-cell is described in conjunction with the following embodiments.

[0141] In some embodiments, determining the current temperature of the first sub-cell based on the heat generation power of the first sub-cell at the previous moment, the temperature of the first sub-cell at the previous moment, the temperature of the second sub-cell at the previous moment, and the ambient temperature corresponding to the first cell at the previous moment includes: determining a first heat transfer between the first sub-cell and the second sub-cell based on the temperatures of the first sub-cell and the second sub-cell at the previous moment; determining a second heat transfer between the first sub-cell and the environment corresponding to the first cell based on the temperature of the first sub-cell at the previous moment and the ambient temperature corresponding to the first cell at the previous moment; determining a third heat generated by the first sub-cell based on the heat generation power of the first sub-cell at the previous moment; and determining the current temperature of the first sub-cell based on the temperature of the first sub-cell at the previous moment, the first heat transfer, the second heat transfer, and the third heat transfer.

[0142] For example, in determining the first heat, the first and second sub-cells are divided into multiple units. For each unit in the first sub-cell, the heat transferred from that unit to the unit in the second sub-cell that is in contact with it is calculated.

[0143] Next, the first sub-cell is considered as an independent whole, and the second sub-cell is considered as an independent whole. The first heat transferred from the first sub-cell to the second sub-cell is determined.

[0144] First, a first temperature difference is determined based on the difference between the temperature of the first sub-cell at the previous moment and the temperature of the second sub-cell at the previous moment. Then, the ratio of the first temperature difference to the contact thermal resistance between the first sub-cell and the second sub-cell is determined based on the first temperature difference. This ratio is the first thermal power corresponding to the first heat. Finally, the first heat is determined based on the product of the first thermal power and the time step corresponding to the heat transfer. The time step can be 1 second.

[0145] The following describes how to determine the second heat.

[0146] First, the second temperature difference is determined based on the difference between the temperature of the first sub-cell at the previous moment and the ambient temperature corresponding to the first cell at the previous moment. Then, the second heat power corresponding to the second heat is determined based on the product of the second temperature difference, the convective heat transfer coefficient of the first sub-cell, and the convective heat transfer area of ​​the first sub-cell. Finally, the second heat is determined based on the product of the second heat power and the time step corresponding to the heat transfer.

[0147] The following describes how to determine the third calorie.

[0148] The third heat source is determined by multiplying the heat generation power of the first sub-cell at the previous moment with the time step corresponding to the heat transfer.

[0149] The following describes how to determine the current temperature of the first sub-cell based on the first heat source, the second heat source, and the third heat source.

[0150] First, the net heat of the first sub-cell is determined based on the difference between the third heat and the first and second heats (i.e., third heat - first heat - second heat). Then, the ratio of the net heat to the product of the net heat of the first sub-cell, the specific heat capacity of the first sub-cell, and the cell mass of the first sub-cell is determined. Finally, the current temperature of the first sub-cell is determined by summing this ratio with the temperature of the first sub-cell at the previous moment.

[0151] In the above embodiments, by determining the first heat transferred between the first sub-cell and the second sub-cell, the second heat transferred between the first sub-cell and the environment, and the third heat generated by the first sub-cell, the temperature of the first sub-cell at the current moment can be accurately determined based on the heat transferred in these three dimensions.

[0152] The following embodiments describe how to determine the temperature of the second cell at the next moment based on the current temperature of the last first cell.

[0153] In some embodiments, determining the temperature of the second cell at the next moment within a cycle based on the current temperature of the last first cell includes: determining the temperature of the second cell at the next moment based on the current temperature of the last first cell, the current temperature of the second cell, and the ambient temperature corresponding to the first cell at the current moment.

[0154] First, based on the current temperature of the last first sub-cell and the current temperature of the second cell, the heat transferred between the last first sub-cell and the second cell is determined. Then, based on the current temperature of the second cell and the current ambient temperature corresponding to the first cell, the heat transferred between the second cell and the corresponding environment is determined. The specific process is similar to determining the first and second heat values, and will not be repeated here. Finally, based on these two heat values, the temperature of the second cell at the next moment is determined. The specific process is similar to determining the current temperature of the first sub-cell, and will not be repeated here.

[0155] In the above embodiments, the influence of multiple dimensions of temperature on the second cell at the next moment is considered in the process of determining the temperature of the second cell at the next moment, namely the current temperature of the last first sub-cell, the current temperature of the second cell, and the current ambient temperature. This helps to improve the accuracy of determining the temperature of the second cell at the next moment, thereby helping to improve the accuracy of thermal spread simulation.

[0156] Figure 7 Schematic diagrams illustrating simulation results of the temperature of each first sub-cell and the temperature of the second cell of this disclosure are shown in some embodiments. Figure 7 Taking a first sub-cell with 7 cells as an example, the temperature of each first sub-cell and the temperature of the second cell are analyzed.

[0157] like Figure 7 As shown, the horizontal axis represents time in seconds, and the vertical axis represents temperature in degrees Celsius. Curve 71 represents the temperature curve of the first sub-cell, curve 72 represents the temperature curve of the second sub-cell, curve 73 represents the temperature curve of the third sub-cell, curve 74 represents the temperature curve of the fourth sub-cell, curve 75 represents the temperature curve of the fifth sub-cell, curve 76 represents the temperature curve of the sixth sub-cell, curve 77 represents the temperature curve of the seventh sub-cell, and curve 78 represents the temperature curve of the second cell.

[0158] like Figure 7 As shown, the temperature of each first sub-chip exhibits a pattern of first increasing and then decreasing. The temperature of the second cell shows a slow increasing trend. Whether there will be a significant increase later depends on whether there is thermal runaway. If there is, the second cell will enter thermal runaway due to thermal runaway. If there is no thermal runaway, the second cell will not enter thermal runaway.

[0159] After determining the temperature of the second cell during the period when the first cell experiences thermal runaway, the risk level of thermal propagation is described below in conjunction with the following embodiments.

[0160] In some embodiments, determining the risk level of heat spread based on the temperature of the second cell during the cycle includes: determining the highest temperature and average temperature of the second cell during the cycle; if the highest temperature of the second cell is less than a temperature threshold, determining the risk level of heat spread as a first level; if the highest temperature of the second cell is greater than or equal to the temperature threshold, determining the risk level of heat spread as a second level; and if the average temperature of the second cell is greater than or equal to the temperature threshold, determining the risk level of heat spread as a third level, wherein the first level is lower than the second level, and the second level is lower than the third level.

[0161] The above embodiments provide a method for determining the risk level of thermal spread. By determining the risk level of thermal spread based on the highest and average temperatures of the second cell within a cycle, the method helps to obtain an accurate risk level of thermal spread and provides reliable technical support for subsequent prediction of the risk of thermal spread in the battery pack or the design of materials between cells in the subsequent battery pack.

[0162] Figure 8 Schematic diagrams illustrating some other embodiments of the thermal propagation simulation method of this disclosure are shown.

[0163] like Figure 8 As shown, the thermal propagation simulation method includes steps 801 to 805.

[0164] In step 801, a thermal runaway test is performed on the third cell to obtain the thermal runaway temperature and the heat generation power curve of the first cell. The third cell is a cell with the same specifications as the first cell.

[0165] In step 802, a three-dimensional geometric model is established, including dividing the first cell into multiple first sub-cells, and dividing the adjacent cells of the first cell into second cells.

[0166] In step 803, the first cell is heated based on the heating plate stop logic (when the temperature of the last first sub-cell reaches the thermal runaway temperature of the first cell).

[0167] In step 804, the heat generation power of each first sub-cell is determined based on the cell thermal runaway trigger logic (i.e., the temperature of the first sub-cell is greater than the thermal runaway temperature for the first time, and the duration of the first time the temperature is greater than the thermal runaway temperature is less than the time threshold).

[0168] In step 805, a three-dimensional heat transfer model is established to determine the temperature of each first sub-cell and the temperature of the second cell. The temperature of the second cell includes the highest temperature and average temperature of the second cell during the period when the first cell experiences thermal runaway.

[0169] After determining the highest and average temperatures of the second cell during the period when the first cell experienced thermal runaway, the risk level of thermal propagation can be determined based on these highest and average temperatures.

[0170] In the above embodiments, establishing a three-dimensional geometric model and a three-dimensional heat transfer model helps to obtain an accurate temperature of the second battery cell, improving the accuracy of predicting the risk of thermal propagation. Furthermore, the above embodiments provide a general-purpose thermal propagation simulation method, reducing the risk of being limited to a single simulation software program for thermal propagation simulation.

[0171] Figure 9 Schematic diagrams of some embodiments of the thermal propagation simulation apparatus of this disclosure are shown.

[0172] like Figure 9 As shown, the heat spread simulation device 90 includes a division unit 91, a heating unit 92, a first determination unit 93, a second determination unit 94, and a third determination unit 95.

[0173] The dividing unit 91 is configured to divide the first cell in the battery model into multiple first sub-cells, wherein the second cell is located on one side of the first cell, the heating plate is located on the other side of the first cell, and the multiple first sub-cells are arranged in order from the heating plate to the first cell.

[0174] Heating unit 92 is configured to heat the first cell based on a heating plate until the temperature of the last first sub-cell reaches the thermal runaway temperature of the first cell.

[0175] The first determining unit 93 is configured to determine the heat generation power of each first sub-cell based on a first relationship between the temperature of the first sub-cell and the thermal runaway temperature.

[0176] The second determining unit 94 is configured to determine the temperature of the second cell during the period in which the first cell experiences thermal runaway, based on the heat generation power of each first sub-cell.

[0177] The third determining unit 95 is configured to determine the risk level of thermal propagation based on the temperature of the second cell during the cycle.

[0178] In the above embodiments, by dividing the first cell and placing a second cell on one side of the first cell and a heating plate on the other side of the first cell, the simulation of thermal runaway of the cell takes into account the characteristics of unilateral heating of the cell and the development of thermal runaway from local to global, which can improve the accuracy of thermal runaway simulation and thus improve the accuracy of predicting the risk of thermal propagation. Furthermore, by determining the temperature of the second cell during the thermal runaway period of the first cell based on the heat generation power of each first sub-cell, the risk of thermal propagation can be determined based on the temperature of the second cell. In determining the temperature of the second cell, the fact that each first sub-cell generates heat when in a thermal runaway state, and that this heat affects the temperature of the second cell, is taken into account, improving the accuracy of determining the temperature of the second cell and thus improving the accuracy of predicting the risk of thermal propagation. In addition, the above embodiments provide a universal thermal propagation simulation method, reducing the risk of being limited to a single simulation software.

[0179] In some embodiments, the first determining unit 93 is further configured to determine the heat generation power of the first sub-cell based on the first relationship, the heat generation power curve of the first cell, and the duration of the time period during which the temperature of the first sub-cell first exceeds the thermal runaway temperature.

[0180] In some embodiments, the thermal propagation simulation device 90 further includes a test unit configured to perform a thermal runaway test on the third battery cell using an adiabatic accelerated calorimeter, and determine a second relationship between the thermal runaway temperature and the temperature and time of the first battery cell, wherein the third battery cell is a battery cell with the same specifications as the first battery cell, and the second relationship is the correspondence between the temperature and time of the first battery cell when it is in thermal runaway; and determine the heat generation power curve of the first battery cell based on the second relationship.

[0181] In some embodiments, the test unit is further configured to determine the heat generation power curve of the first battery cell based on the second relationship, the specific heat capacity of the first battery cell, and the mass of the first battery cell.

[0182] In some embodiments, the first determining unit 93 is further configured to determine whether the first sub-cell is in thermal runaway based on the first relationship and the duration; and in the case that the first sub-cell is in thermal runaway, to determine the heat generation power of the first sub-cell based on the duration and the heat generation power curve of the first cell.

[0183] In some embodiments, the first determining unit 93 is further configured to: determine that the first sub-cell is in thermal runaway when the temperature of the first sub-cell is first greater than the thermal runaway temperature and the duration is less than a time threshold; determine that the first sub-cell is not in thermal runaway when the temperature of the first sub-cell is less than or equal to the thermal runaway temperature and no instance of the temperature of the first sub-cell being greater than the thermal runaway temperature occurs; and determine that the first sub-cell is not in thermal runaway when the duration is greater than or equal to a time threshold.

[0184] In some embodiments, the first determining unit 93 is further configured to determine that the heat generation power of the first sub-cell is zero when the first sub-cell is not in thermal runaway.

[0185] In some embodiments, the second determining unit 94 is further configured to, for each first sub-cell, within a cycle, determine the current temperature of the first sub-cell based on the heat generation power of the first sub-cell at the previous moment, the temperature of the first sub-cell at the previous moment, the temperature of the second sub-cell at the previous moment, and the ambient temperature corresponding to the first cell at the previous moment, wherein, if the first sub-cell is not the last first sub-cell, the second sub-cell is the first sub-cell adjacent to the first sub-cell, and if the first sub-cell is the last first sub-cell, the second sub-cell is the first sub-cell adjacent to the first sub-cell and the second cell; and determine the temperature of the second cell at the next moment within the cycle based on the current temperature of the last first sub-cell.

[0186] In some embodiments, the second determining unit 94 is further configured to: determine a first heat transfer between the first sub-cell and the second sub-cell based on the temperature of the first sub-cell at the previous moment and the temperature of the second sub-cell at the previous moment; determine a second heat transfer between the first sub-cell and the environment corresponding to the first sub-cell based on the temperature of the first sub-cell at the previous moment and the ambient temperature corresponding to the first sub-cell at the previous moment; determine a third heat generation of the first sub-cell based on the heat generation power of the first sub-cell at the previous moment; and determine the current temperature of the first sub-cell based on the temperature of the first sub-cell at the previous moment, the first heat transfer, the second heat transfer, and the third heat transfer.

[0187] In some embodiments, the second determining unit 94 is further configured to determine the temperature of the second cell at the next moment based on the current temperature of the last first sub-cell, the current temperature of the second cell, and the ambient temperature corresponding to the first cell at the current moment.

[0188] In some embodiments, the third determining unit 95 is further configured to determine the highest temperature and average temperature of the second battery cell within the cycle based on the temperature of the second battery cell within the cycle; if the highest temperature of the second battery cell is less than a temperature threshold, determine the risk level of heat spread as a first level; if the highest temperature of the second battery cell is greater than or equal to the temperature threshold, determine the risk level of heat spread as a second level; if the average temperature of the second battery cell is greater than or equal to the temperature threshold, determine the risk level of heat spread as a third level, wherein the first level is lower than the second level, and the second level is lower than the third level.

[0189] In some embodiments, the period during which the first cell experiences thermal runaway is the time period from when the last first sub-cell begins to experience thermal runaway until the last first sub-cell ends to experience thermal runaway.

[0190] Figure 10 Schematic diagrams of other embodiments of the thermal propagation simulation apparatus of this disclosure are shown.

[0191] The first memory 1001 is used to store one or more computer-readable instructions. The first memory 1001 may include any combination of various forms of computer-readable storage media, such as volatile memory and / or non-volatile memory, including but not limited to random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), read-only memory (ROM), and flash memory. The first memory 1001 may, for example, store operating systems, application programs, boot loaders, databases, and other programs, as well as various application programs and various data.

[0192] The first processor 1002 is configured to execute computer-readable instructions to implement the thermal propagation simulation method or the method of any of the foregoing embodiments. Specific implementations of each step of the method can be found in the above embodiments; repeated details will not be elaborated here.

[0193] The first processor 1002 can be configured to perform the steps in the above embodiments. The first processor 1002 can be embodied in various processing devices, such as a central processing unit (CPU), a network processor (NP), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The central processing unit (CPU) can be an x86 or ARM architecture, etc.

[0194] The first processor 1002 and the first memory 1001 can communicate with each other directly or indirectly. For example, the first processor 1002 and the first memory 1001 can communicate through a network. The network can include a wireless network, a wired network, and / or any combination of wireless and wired networks. The first processor 1002 and the first memory 1001 can also communicate with each other through a system bus, which is not limited in this disclosure.

[0195] It should be noted that Figure 10 The components of the thermal spread simulation device 90 shown are merely exemplary and not limiting. The thermal spread simulation device 90 may have other components depending on the specific application requirements. The first processor 1002 can control other components in the thermal spread simulation device 90 to perform the desired functions.

[0196] The thermal propagation simulation device 90 can be implemented by software, firmware and / or hardware, and can be integrated into a device with the relevant application installed.

[0197] In the above embodiments, by dividing the first cell and placing a second cell on one side of the first cell and a heating plate on the other side of the first cell, the simulation of thermal runaway of the cell takes into account the characteristics of unilateral heating of the cell and the development of thermal runaway from local to global, which can improve the accuracy of thermal runaway simulation and thus improve the accuracy of predicting the risk of thermal propagation. Furthermore, by determining the temperature of the second cell during the thermal runaway period of the first cell based on the heat generation power of each first sub-cell, the risk of thermal propagation can be determined based on the temperature of the second cell. In determining the temperature of the second cell, the fact that each first sub-cell generates heat when in a thermal runaway state, and that this heat affects the temperature of the second cell, is taken into account, improving the accuracy of determining the temperature of the second cell and thus improving the accuracy of predicting the risk of thermal propagation. In addition, the above embodiments provide a universal thermal propagation simulation method, reducing the risk of being limited to a single simulation software.

[0198] Figure 11 Schematic diagrams showing further embodiments of the thermal propagation simulation apparatus of this disclosure are provided.

[0199] like Figure 11 As shown, the thermal propagation simulation device 90 of this embodiment includes: a second memory 1101 and a second processor 1102 coupled to the second memory 1101. The second processor 1102 is configured to execute the thermal propagation simulation method of any of the foregoing embodiments based on instructions stored in the second memory 1101.

[0200] The second memory 1101 may include, for example, system memory, fixed non-volatile storage media, etc. The system memory stores, for example, the operating system, application programs, boot loader, and other programs.

[0201] The thermal propagation simulation device 90 may also include input / output interfaces 1103, network interfaces 1104, and storage interfaces 1105. These interfaces 1103, 1104, 1105, as well as the second memory 1101 and the second processor 1102, can be connected, for example, via a bus 1106. Specifically, the input / output interface 1103 provides a connection interface for input / output devices such as monitors, mice, keyboards, touchscreens, microphones, and speakers. The network interface 1104 provides a connection interface for various networked devices. The storage interface 1105 provides a connection interface for external storage devices such as SD cards and USB flash drives.

[0202] In the above embodiments, by dividing the first cell and placing a second cell on one side of the first cell and a heating plate on the other side of the first cell, the simulation of thermal runaway of the cell takes into account the characteristics of unilateral heating of the cell and the development of thermal runaway from local to global, which can improve the accuracy of thermal runaway simulation and thus improve the accuracy of predicting the risk of thermal propagation. Furthermore, by determining the temperature of the second cell during the thermal runaway period of the first cell based on the heat generation power of each first sub-cell, the risk of thermal propagation can be determined based on the temperature of the second cell. In determining the temperature of the second cell, the fact that each first sub-cell generates heat when in a thermal runaway state, and that this heat affects the temperature of the second cell, is taken into account, improving the accuracy of determining the temperature of the second cell and thus improving the accuracy of predicting the risk of thermal propagation. In addition, the above embodiments provide a universal thermal propagation simulation method, reducing the risk of being limited to a single simulation software.

[0203] In some embodiments, a computer program product is protected, comprising a computer program or instructions that, when executed by a processor, implement the thermal propagation simulation method described above. The computer program product includes a computer program carried on a computer-readable medium, containing program code for performing the methods shown in the flowchart. In such embodiments, the computer program can be downloaded and installed from a network, from a storage device, or from a ROM via a thermal propagation simulation device. When the computer program is executed by a CPU, it performs the functions defined in the methods of the embodiments of this disclosure.

[0204] Those skilled in the art will understand that embodiments of this disclosure can be provided as methods, systems, or computer program products. Therefore, this disclosure can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this disclosure can take the form of a computer program product embodied on one or more computer-usable non-transitory storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0205] This concludes the detailed description of the thermal propagation simulation method, apparatus, and program products disclosed herein. To avoid obscuring the concept of this disclosure, some details known in the art have not been described. Those skilled in the art can fully understand how to implement the technical solutions disclosed herein based on the above description.

[0206] The methods and systems of this disclosure may be implemented in many ways. For example, they may be implemented by software, hardware, firmware, or any combination of software, hardware, and firmware. The above-described order of steps for the methods is for illustrative purposes only, and the steps of the methods of this disclosure are not limited to the order specifically described above unless otherwise specifically stated. Furthermore, in some embodiments, this disclosure may also be implemented as a program recorded on a recording medium, the program including machine-readable instructions for implementing the methods according to this disclosure. Thus, this disclosure also covers recording media storing programs for performing the methods according to this disclosure.

[0207] While specific embodiments of this disclosure have been described in detail by way of example, those skilled in the art should understand that the examples are for illustrative purposes only and not intended to limit the scope of this disclosure. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this disclosure. The scope of this disclosure is defined by the appended claims.

Claims

1. A method for simulating thermal propagation, comprising: The first cell in the battery model is divided into multiple first sub-cells, wherein the second cell is located on one side of the first cell and the heating plate is located on the other side of the first cell, and the multiple first sub-cells are arranged in order from the heating plate to the first cell; The first cell is heated by the heating plate until the temperature of the last first sub-cell reaches the thermal runaway temperature of the first cell. For each first sub-cell, the heat generation power of the first sub-cell is determined based on a first relationship between the temperature of the first sub-cell and the thermal runaway temperature. Based on the heat generation power of each first sub-cell, the temperature of the second cell during the period when the first cell experiences thermal runaway is determined; The risk level of thermal propagation is determined based on the temperature of the second cell during the cycle.

2. The thermal propagation simulation method according to claim 1, wherein, The step of determining the heat generation power of the first sub-cell based on the first relationship between the temperature of the first sub-cell and the thermal runaway temperature includes: The heat generation power of the first sub-cell is determined based on the first relationship, the heat generation power curve of the first cell, and the duration of the time when the temperature of the first sub-cell first exceeds the thermal runaway temperature.

3. The thermal propagation simulation method according to claim 2 further includes: Using an adiabatic accelerated calorimeter, a thermal runaway test was conducted on the third battery cell, and a second relationship between the thermal runaway temperature and the temperature and time of the first battery cell was determined. The third battery cell is a battery cell with the same specifications as the first battery cell, and the second relationship is the correspondence between the temperature and time of the first battery cell when it is in thermal runaway. Based on the second relationship, the heat generation power curve of the first battery cell is determined.

4. The thermal propagation simulation method according to claim 3, wherein, The step of determining the heat generation power curve of the first battery cell based on the second relationship includes: Based on the second relationship, the specific heat capacity of the first battery cell, and the mass of the first battery cell, the heat generation power curve of the first battery cell is determined.

5. The thermal propagation simulation method according to claim 3, wherein, The step of determining the heat generation power of the first sub-cell based on the first relationship, the heat generation power curve of the first cell, and the duration of the time when the temperature of the first sub-cell first exceeds the thermal runaway temperature includes: Based on the first relationship and the duration, determine whether the first sub-cell is in thermal runaway; When the first sub-cell is in thermal runaway, the heat generation power of the first sub-cell is determined based on the duration of the runaway and the heat generation power curve of the first cell.

6. The thermal propagation simulation method according to claim 5, wherein, Determining whether the first sub-cell is in thermal runaway based on the first relationship and the duration includes: If the temperature of the first sub-cell is greater than the thermal runaway temperature for the first time and the duration is less than the time threshold, the first sub-cell is determined to be in thermal runaway. If the temperature of the first sub-cell is less than or equal to the thermal runaway temperature, and there is no case where the temperature of the first sub-cell is greater than the thermal runaway temperature, then it is determined that the first sub-cell is not in thermal runaway. If the duration is greater than or equal to the time threshold, it is determined that the first sub-cell is not in thermal runaway.

7. The thermal propagation simulation method according to claim 5, wherein, The step of determining the heat generation power of the first sub-cell based on the first relationship, the heat generation power curve of the first cell, and the duration of the time when the temperature of the first sub-cell first exceeds the thermal runaway temperature further includes: If the first sub-cell is not in thermal runaway, the heat generation power of the first sub-cell is determined to be zero.

8. The thermal propagation simulation method according to any one of claims 1 to 7, wherein, Determining the temperature of the second cell during the period when the first cell experiences thermal runaway, based on the heat generation power of each first sub-cell, includes: For each first sub-cell, within the cycle, the current temperature of the first sub-cell is determined based on the heat generation power of the first sub-cell at the previous moment, the temperature of the first sub-cell at the previous moment, the temperature of the second sub-cell at the previous moment, and the ambient temperature corresponding to the first cell at the previous moment. Wherein, if the first sub-cell is not the last first sub-cell, the second sub-cell is the first sub-cell adjacent to the first sub-cell; if the first sub-cell is the last first sub-cell, the second sub-cell is the first sub-cell and the second cell adjacent to the first sub-cell. The temperature of the second cell at the next moment within the cycle is determined based on the current temperature of the last first cell.

9. The thermal propagation simulation method according to claim 8, wherein, The step of determining the current temperature of the first sub-cell based on the heat generation power of the first sub-cell at the previous moment, the temperature of the first sub-cell at the previous moment, the temperature of the second sub-cell at the previous moment, and the ambient temperature corresponding to the first cell at the previous moment includes: Based on the temperature of the first sub-cell at the previous moment and the temperature of the second sub-cell at the previous moment, determine the first heat transfer between the first sub-cell and the second sub-cell; Based on the temperature of the first sub-cell at the previous moment and the ambient temperature corresponding to the first cell at the previous moment, the second heat transferred between the first sub-cell and the environment corresponding to the first cell is determined. Based on the heat generation power of the first sub-cell at the previous moment, determine the third heat generated by the first sub-cell. The current temperature of the first sub-cell is determined based on the temperature of the first sub-cell at the previous moment, the first heat, the second heat, and the third heat.

10. The thermal propagation simulation method according to claim 8, wherein, Determining the temperature of the second cell at the next moment within the cycle based on the current temperature of the last first cell includes: The temperature of the second cell at the next moment is determined based on the current temperature of the last first cell, the current temperature of the second cell, and the current ambient temperature of the first cell.

11. The thermal propagation simulation method according to any one of claims 1 to 7, wherein, The determination of the risk level of heat spread based on the temperature of the second cell during the cycle includes: Based on the temperature of the second cell during the cycle, determine the highest temperature and average temperature of the second cell during the cycle; If the highest temperature of the second battery cell is less than the temperature threshold, the risk level of heat spread is determined to be Level 1. If the highest temperature of the second cell is greater than or equal to the temperature threshold, the risk level of heat spread is determined to be Level 2. If the average temperature of the second cell is greater than or equal to the temperature threshold, the risk level of heat spread is determined to be Level 3, wherein the first level is lower than the second level, and the second level is lower than the third level.

12. The thermal propagation simulation method according to any one of claims 1 to 7, wherein, The period during which the first cell experiences thermal runaway is the time period from when the last first sub-cell begins to experience thermal runaway until the last first sub-cell ends to experience thermal runaway.

13. A thermal propagation simulation device, comprising: The dividing unit is configured to divide a first cell in the battery model into a plurality of first sub-cells, wherein a second cell is located on one side of the first cell, a heating plate is located on the other side of the first cell, and the plurality of first sub-cells are arranged in order from the heating plate to the first cell. The heating unit is configured to heat the first cell based on the heating plate until the temperature of the last first sub-cell reaches the thermal runaway temperature of the first cell. The first determining unit is configured to determine the heat generation power of each first sub-cell based on a first relationship between the temperature of the first sub-cell and the thermal runaway temperature. The second determining unit is configured to determine the temperature of the second cell during the period in which the first cell experiences thermal runaway, based on the heat generation power of each first sub-cell. The third determining unit is configured to determine the risk level of thermal spread based on the temperature of the second cell during the cycle.

14. A thermal propagation simulation device, comprising: Memory; and A processor coupled to the memory, the processor being configured to execute the thermal propagation simulation method of any one of claims 1 to 12 based on instructions stored in the memory.

15. A computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the thermal propagation simulation method according to any one of claims 1 to 12.

16. A computer program product comprising a computer program that, when executed by a processor, implements the thermal propagation simulation method according to any one of claims 1 to 12.

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