Heating safety evaluation device

Abstract

To reduce a load of a circumference heating device while enabling an evaluation of a critical temperature that a thermal runaway occurs in a sample even having cooling means.SOLUTION: A heating safety evaluation device comprises: a sensor; a heating device; a cooling device; and a control device. The control device repeats a predetermined sequential control. The sequential control is a control that a sample is heated, and thereafter, is set to a pseudo heat insulation state by a heating by a circumference heating device while trying a convergence of an own heat generation by a cooling of the sample by the cooling device when the own heat generation is detected by the sensor. The pseudo heat insulation state is a state that a thermal balance between the sample to be cooled by the cooling device and their circumference becomes zero. The heating safety evaluation device evaluates a temperature of the sample that the own heat generation is not converged as a critical temperature that a thermal runaway occurs in the sample also by cooling by a cooling device in a repetition of the sequential control.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a heating safety evaluation device for evaluating the heating safety of a sample.

Background Art

[0002] In recent years, the popularity of electric vehicles such as EVs and HEVs has been increasing. In these electric vehicles, improving safety, especially the safety of the battery, has become an issue.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Among heating safety evaluation devices as devices for evaluating the heating safety of batteries and other objects mounted on electric vehicles, there are those configured as follows. That is, the heating safety evaluation device includes a sensor that detects the self-heating of a sample such as a battery, and a surrounding heating device configured to be able to heat the surroundings of the sample.

[0005] The heating safety evaluation device heats the sample using the surrounding heating device. Then, when the self-heating of the sample is detected by the sensor, while controlling the surrounding heating device to a predetermined quasi-adiabatic state, the self-heating of the sample is observed over time. Here, the "quasi-adiabatic state" refers to a state where the heat balance between the sample and its surroundings becomes zero.

[0006] According to the above heating safety evaluation device, the temperature change of the sample in the adiabatic state can be tracked. From this, the self-heating rate of the sample at each temperature can be evaluated. However, the present inventors have focused on the following problems.

[0007] That is, for an actual battery, some cooling means in a predetermined form is often provided at a predetermined location. However, regarding the critical temperature at which the temperature of the sample continues to rise due to self-heating even with those cooling means, that is, regarding the critical temperature at which thermal runaway occurs even with cooling means, it cannot be evaluated. Further, when the self-heating of the sample is large, the load on the ambient heating device for maintaining the quasi-adiabatic state becomes large.

[0008] Note that, above, the case where the evaluation target is a battery has been described as an example, but the same problems can occur even when the evaluation target is other objects.

[0009] The present invention has been made in view of the above circumstances, and aims to enable evaluation of the critical temperature at which the sample undergoes thermal runaway even with cooling means, and to reduce the load on the ambient heating device.

Means for Solving the Problems

[0010] The inventors of the present invention have found that the above object can be achieved by providing a cooling device for cooling the sample and performing predetermined control, and thus have arrived at the present invention. The present invention is a heating safety evaluation device as described in (1) to (10) below.

[0011] (1) A sensor for detecting self-heating of the sample, An ambient heating device configured to be able to heat the periphery of the sample, A heating safety evaluation device comprising: A cooling device configured to be able to cool the sample, A control device that repeatedly performs a predetermined series of controls, and The series of controls is a control for heating the sample, and then, when the self-heating is detected by the sensor, attempting to converge the self-heating by cooling the sample by the cooling device, while making the quasi-adiabatic state by heating with the ambient heating device. The pseudo-adiabatic state is a state in which the heat balance between the sample cooled by the cooling device and its surroundings becomes zero. A heating safety evaluation device that evaluates, as a critical temperature at which the sample will undergo thermal runaway even with cooling by the cooling device, the temperature of the sample for which self-heating did not converge during the repetition of the series of controls.

[0012] According to this configuration, by mimicking the configuration such as the arrangement and cooling rate of the cooling device for the actual cooling means, the critical temperature at which the sample will undergo thermal runaway even with the presence of the cooling means can be evaluated. Further, since the sample is cooled by the cooling device, the temperature rise of the sample due to its self-heating is suppressed accordingly. Therefore, the load on the surrounding heating device for maintaining the pseudo-adiabatic state can be reduced accordingly, and the heating safety of a sample with a larger heat generation rate can be evaluated.

[0013] As described above, according to this configuration, the critical temperature at which the sample will undergo thermal runaway even with the presence of the cooling means can be evaluated, and the load on the surrounding heating device can be reduced.

[0014] (2) It is provided with a heating device configured to be able to heat the sample. The series of controls is a control for heating the sample, and then, when the self-heating is detected by the sensor, while cooling the sample by the cooling device and heating the sample by the heating device, making it in a pseudo-adiabatic state by heating with the surrounding heating device. The pseudo-adiabatic state is a state in which the heat balance between the sample cooled by the cooling device and heated by the heating device and its surroundings becomes zero. The heating safety evaluation device according to (1) above.

[0015] According to this configuration, by the heating safety evaluation device including not only the cooling device but also the heating device, the temperature distribution around the sample can be more accurately mimicked to the actual temperature distribution.

[0016] (3) The cooling device includes an element having a heat absorption surface and a heat dissipation surface, and cools the sample by the heat absorption surface. The heating safety evaluation device according to (1) or (2) above.

[0017] According to this configuration, the heat balance by the cooling device in the system including the sample and its surroundings can be made zero.

[0018] (4) When the temperature increase rate of the sample is 0.02 °C / min or less, the control device regards that the self-heating has converged. The heating safety evaluation device according to any one of (1) to (3) above.

[0019] Generally, the detection limit of the temperature increase rate is 0.02 °C / min. When it is below the detection limit, by regarding that the self-heating has converged, the evaluation test can be performed with maximum accuracy.

[0020] (5) The cooling device includes a Peltier element for cooling that cools the sample by the heat absorption surface, and a cooling circuit that supplies power to the Peltier element for cooling. The control device controls the cooling device by controlling the cooling circuit. The heating safety evaluation device according to (3) above.

[0021] According to this configuration, by controlling the current flowing through the Peltier element for cooling, the cooling rate by the cooling device can be quantitatively controlled.

[0022] (6) The heating device includes a Peltier element for heating that heats the sample by the heat dissipation surface, and a heating circuit that supplies power to the Peltier element for heating. The control device controls the heating device by controlling the heating circuit. The heating safety evaluation device according to (2) above.

[0023] According to this configuration, by controlling the current flowing through the heating Peltier element, the heating rate by the heating device can be quantitatively controlled.

[0024] (7) A plurality of Peltier elements are installed for the sample. The heating safety evaluation device according to any one of (1) to (6) above.

[0025] According to this configuration, by controlling a plurality of Peltier elements, the temperature and temperature distribution of the sample can be accurately controlled. Therefore, it is possible to more accurately simulate the actual state.

[0026] (8) The heating device includes a heating Peltier element that heats the sample by a heating surface, and a heating circuit that supplies power to the heating Peltier element. The cooling device includes a cooling Peltier element that cools the sample by a heat absorption surface, and a cooling circuit that supplies power to the cooling Peltier element. A predetermined part of the sample is heated by the heating surface of the heating Peltier element. Another part of the sample is cooled by the heat absorption surface of the cooling Peltier element. The heating safety evaluation device according to (2) above.

[0027] According to this configuration, both heating and cooling of the sample can be performed by a plurality of Peltier elements.

[0028] (9) Further includes a sample container for storing the sample. The sample container is in the shape of a hexahedron. The heating safety evaluation device according to any one of (1) to (8) above.

[0029] Actual containers for storing batteries and the like are often in the shape of a hexahedron. Therefore, according to this configuration, it is easy to conduct tests simulating actual containers.

[0030] (10) Further comprising a sample container for storing the sample, The sample container is cylindrical, The heating safety evaluation device according to any one of (1) to (8) above.

[0031] Actual containers for storing batteries and the like are often cylindrical. Therefore, according to this configuration, it is easy to conduct a test imitating an actual container.

Advantages of the Invention

[0032] As described above, according to the configuration of (1) above, it is possible to evaluate the critical temperature at which the sample undergoes thermal runaway even in the presence of a cooling means, and to reduce the load on the surrounding heating device. Furthermore, according to the configurations of (2) to (10) that cite the configuration of (1) above, respective additional effects can be obtained.

Brief Description of the Drawings

[0033]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0034] Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments at all, and can be implemented with appropriate modifications without departing from the gist of the present invention.

[0035] [First Embodiment] As shown in FIG. 1, the heating safety evaluation apparatus 100 of the present embodiment includes a system container 10, a sample container 30, a first sensor 41, a second sensor 42, a surrounding heating device 20, a heating device 50, a cooling device 60, a control device 70, and an evaluation device 80. Hereinafter, the first sensor 41 and the second sensor 42 are simply referred to as "sensors 41, 42".

[0036] In the present embodiment, the sample Sp is a battery. The sample container 30 stores the sample Sp. The sample Sp preferably abuts on the sample container 30 from the inside. However, when it cannot abut, it is preferable to make the sample Sp and the sample container 30 as close as possible. Examples of such a case where it cannot abut include a case where the battery as the sample Sp has protruding terminals, and thus the peripheral portion of the terminals in the sample Sp cannot abut on the sample container 30 from the inside. In such a case, a heat transfer material is provided between the portion of the sample Sp that cannot abut on the sample container 30 and the sample container 30. The heat transfer material preferably has a heat capacity sufficiently smaller (for example, 1 / 20 or less) than that of the sample and a thermal conductivity equal to or higher than that of the sample.

[0037] The sample container 30 mimics the housing of an IPU (Intelligent Power Unit) in which a battery is actually mounted. However, instead of this, the present embodiment may be implemented by using the content of the battery as the sample Sp and the exterior of the battery itself as the sample container 30.

[0038] The system container 10 stores the sample container 30. A heat insulating material 15 for heat-insulating the system container 10 is provided around the system container 10. The first sensor 41 detects the surface temperature Ta of the sample container 30 and, based on the surface temperature Ta, detects the temperature of the sample Sp and the self-heating of the sample Sp. The second sensor 42 detects the ambient temperature Tb of the sample container 30 in the system container 10.

[0039] The heating device 50 is configured to be able to heat the sample Sp. The cooling device 60 is configured to be able to cool the sample Sp. Specifically, the heating device 50 heats the sample Sp by heating the sample container 30. The cooling device 60 cools the sample Sp by cooling the sample container 30. More specifically, as shown in FIG. 2, the heating device 50 includes a plurality of heating Peltier elements Ph and a heating circuit Ch. The cooling device 60 includes a plurality of cooling Peltier elements Pc and a cooling circuit Cc.

[0040] Each heating Peltier element Ph and each cooling Peltier element Pc are both Peltier elements, and include a heat generation surface that generates heat when an electric current flows and a heat absorption surface that absorbs heat when an electric current flows. For each heating Peltier element Ph, the heat generation surface is in contact with the sample container 30. For each cooling Peltier element Pc, the heat absorption surface is in contact with the sample container 30. Hereinafter, the heating Peltier element Ph and the cooling Peltier element Pc are referred to as "Peltier elements Ph, Pc".

[0041] The heating circuit Ch is a circuit for supplying power to each heating Peltier element Ph, and includes a heating switch SwH. Through the heating switch SwH, the power supply Ps is electrically connected to each heating Peltier element Ph. Therefore, when the heating switch SwH is turned ON, each heating Peltier element Ph heats the sample container 30 with the heat generation surface. As a result, the sample Sp is heated. On the other hand, when the heating switch SwH is turned OFF, the heating is stopped.

[0042] The cooling circuit Cc is a circuit for supplying power to each cooling Peltier element Pc, and includes a cooling switch SwC. Through the cooling switch SwC, the power supply Ps is electrically connected to each cooling Peltier element Pc. Therefore, when the cooling switch SwC is turned ON, each cooling Peltier element Pc cools the sample container 30 with the heat absorption surface. As a result, the sample Sp is cooled. On the other hand, when the cooling switch SwC is turned OFF, the cooling is stopped.

[0043] Furthermore, these heating circuits Ch and cooling circuits Cc are configured to quantitatively control the outputs of the Peltier elements Ph and Pc. Specifically, for example, the heating switch SwH and the cooling switch SwC are semiconductor switches, and a mode of duty control can be mentioned. Also, for example, semiconductor switches may be provided for each of the Peltier elements Ph and Pc, and the outputs of the Peltier elements Ph and Pc may be quantitatively controlled by duty-controlling these semiconductor switches.

[0044] The ambient heating device 20 shown in FIG. 1 is configured to be able to heat the periphery of the sample container 30 within the system container 10. The ambient heating device 20, under a predetermined situation, makes a pseudo-adiabatic state by heating the periphery of the sample container 30. Here, the "pseudo-adiabatic state" is a state in which the heat balance between the sample Sp heated by the heating device 50 and cooled by the cooling device 60 and its surroundings becomes zero. In this pseudo-adiabatic state, the surface temperature Ta of the sample container 30 detected by the first sensor 41 and the peripheral temperature Tb of the sample container 30 detected by the second sensor 42 are kept substantially the same.

[0045] The control device 70 controls the ambient heating device 20, the heating device 50, and the cooling device 60 based on the information from the sensors 41 and 42. That is, as shown in FIG. 2, the control device 70 controls the heating device 50 and the cooling device 60 and also controls the ambient heating device 20. The details of the control by this control device 70 will be described later.

[0046] The evaluation device 80 shown in FIG. 1 evaluates the critical temperature Tnr at which the sample Sp undergoes thermal runaway from the temperature change of the sample Sp. Here, "Tnr" is an abbreviation for "Temperature of no return". The details of the evaluation by this evaluation device 80 will be described later.

[0047] The control device 70 and the evaluation device 80 may be configured by, for example, the same computer or by separate computers.

[0048] The sample container 30 shown in FIG. 1 may be hexahedral as shown in FIG. 3, for example, or may be cylindrical as shown in FIG. 4. Specifically, as described above, the shape of the sample container 30 may appropriately imitate the shape of the actual IPU housing.

[0049] As shown in FIGS. 3 and 4, a plurality of Peltier elements Ph and Pc are installed in the sample container 30. Regarding the arrangement and cooling rate of each cooling Peltier element Pc, it is advisable to imitate the arrangement and cooling rate of each cooling means installed in the actual IPU housing. Regarding the arrangement and heating rate of each heating Peltier element Ph, it is advisable to imitate the arrangement and heating rate of each heat source installed around the actual IPU housing.

[0050] Next, with reference to the flowchart of FIG. 5, the details of the control by the control device 70 and the evaluation by the evaluation device 80 will be described. Note that the S before the numbers mentioned below is an abbreviation for "step". For S1 to S5, the control device 70 performs them, and for S6, the evaluation device 80 performs it. The control of S1 to S5 may be read as "series control". The series control is performed while heating the sample container 30 by the heating device 50 and cooling the sample container 30 by the cooling device 60.

[0051] First, in S1, the control device 70 heats the periphery of the sample container 30 using the ambient heating device 20. In the subsequent S2, it waits for a predetermined time. By this, it waits for the heat of the periphery of the sample container 30 to be transmitted to the sample container 30 and the sample Sp.

[0052] In the subsequent S3, it is determined whether or not the self-heating of the sample Sp is detected by the first sensor 41. If the determination is negative, that is, if the self-heating is not detected, it returns to S1 and repeats S1 to S3. On the other hand, if the determination is positive, that is, if the self-heating is detected, it proceeds to S4.

[0053] In S4, the periphery of the sample container 30 is heated using the surrounding heating device 20 to control it to a pseudo-insulated state. That is, control is performed so that the heat balance between the sample Sp heated by the heating device 50 and cooled by the cooling device 60 and its surroundings becomes zero. Then, observe for a while.

[0054] In the subsequent S5, it is determined whether or not the self-heating of the sample Sp has converged. Specifically, for example, in S5, it is determined whether or not the self-heating of the sample Sp has converged until a predetermined time elapses or until the sample Sp rises by a predetermined temperature.

[0055] Note that the "convergence" of the self-heating here means that the temperature rise of the sample Sp due to self-heating stops. Specifically, in this embodiment, the detection limit of the temperature rise rate by the first sensor 41 is 0.02 °C / min. Therefore, if the temperature rise rate of the sample Sp is within 0.02 °C / min or less, the control device 70 determines that the self-heating has converged.

[0056] If an affirmative determination is made in this S5, that is, if the self-heating has converged, return to S1 and repeat S1 to S5. On the other hand, if a negative determination is made in this S5, that is, if the self-heating has not converged, proceed to S6.

[0057] In S6, the evaluation device 80 evaluates the temperature of the sample Sp when self-heating was detected in the last S3 as the critical temperature Tnr at which the sample Sp will also undergo thermal runaway even with cooling by the cooling device 60.

[0058] Next, while referring to FIG. 6, the operation according to the above flow will be described. Note that the vertical axis in FIG. 6 represents the heating rate and the cooling rate in logarithmic scale. Also, the lower limit of the vertical axis in FIG. 6 indicates 0.02 °C / min. Hereinafter, a predetermined temperature is referred to as "first temperature T1", and predetermined temperatures that are successively higher than that are referred to as "second temperature T2", "third temperature T3", and "fourth temperature T4", respectively. Also, hereinafter, the total cooling rate of the sample Sp by the heating device 50 and the cooling device 60 is referred to as "cooling rate Cr". That is, the cooling rate Cr is the cooling rate after canceling the heating by the heating device 50.

[0059] Here, a case where the self-heating rate SHr and the cooling rate Cr of the sample Sp have the following relationship will be described as an example. The sample Sp starts self-heating at the first temperature T1. When the sample Sp is between the first temperature T1 and the second temperature T2, the self-heating rate SHr is smaller than the cooling rate Cr. When the sample Sp is between the second temperature T2 and the third temperature T3, the self-heating rate SHr is larger than the cooling rate Cr. When the sample Sp is between the third temperature T3 and the fourth temperature T4, the self-heating rate SHr becomes smaller than the cooling rate Cr again. When the sample Sp reaches the fourth temperature T4 or higher, the self-heating rate SHr becomes larger than the cooling rate Cr again. And at this fourth temperature T4 or higher, this magnitude relationship is maintained.

[0060] First, when the temperature of the sample Sp is less than the first temperature T1, after S1 and S2 shown in FIG. 5, by making a negative determination at S3, that is, by not detecting self-heating, S1 to S3 are repeated. By the heating at S1 during the repetition of S1 to S3, the temperature of the sample Sp shown on the horizontal axis in FIG. 6 rises to the first temperature T1 or higher. Thereby, the sample Sp starts self-heating. However, at this time, since the self-heating rate SHr is smaller than the cooling rate Cr, the self-heating is not detected. Therefore, S1 to S3 are repeated.

[0061] During the heating at S1 within the repetition of S1 to S3, the temperature of the sample Sp shown on the horizontal axis of FIG. 6 rises to the second temperature T2 or higher. As a result, the self-heating rate SHr becomes greater than the cooling rate Cr, and the self-heating is detected. Therefore, it proceeds to S4 shown in FIG. 5 and enters a pseudo-adiabatic state. Due to the self-heating in the pseudo-adiabatic state, the temperature of the sample Sp rises to the third temperature T3 or higher. At this point, again, the self-heating rate SHr becomes smaller than the cooling rate Cr, and the self-heating of the sample Sp is no longer detected. That is, the self-heating of the sample Sp converges and a positive determination is made at S5 shown in FIG. 5. Therefore, it returns to S1.

[0062] After that, since the self-heating rate SHr is smaller than the cooling rate Cr, S1 to S3 are repeated. By heating at S1 within the repetition of S1 to S3, the temperature of the sample Sp shown on the horizontal axis of FIG. 6 rises to the fourth temperature T4 or higher. As a result, again, the self-heating rate SHr becomes greater than the cooling rate Cr, and self-heating is detected. Therefore, it proceeds to S4 shown in FIG. 5 and enters a pseudo-adiabatic state. After that, as shown in FIG. 6, this magnitude relationship, that is, the state where the self-heating rate SHr is greater than the cooling rate Cr, is maintained. From this, the self-heating of the sample Sp continues to be detected and does not converge no matter how much time passes. Therefore, a negative determination is made at S5 in FIG. 5 and it proceeds to S6.

[0063] At S6, the temperature of the sample Sp when self-heating was detected at the last S3, that is, the fourth temperature T4 shown in FIG. 6 or a temperature slightly higher than that, is evaluated as the critical temperature Tnr at which the sample Sp will thermally runaway even by cooling with the cooling device 60. The evaluation result, that is, the critical temperature Tnr, is output by being displayed on a display unit such as a display.

[0064] In addition, in the same sample Sp as in the case of FIG. 6, when the setting of the cooling rate Cr is increased, the final intersection point of the cooling rate Cr and the self-heating rate SHr shifts to the right, that is, when T4 shifts to the right, the critical temperature Tnr at which the thermal runaway occurs increases. Further, in the same sample Sp as in the case of FIG. 6, when the setting of the cooling rate Cr is decreased, the final intersection point of the cooling rate Cr and the self-heating rate SHr shifts to the left, that is, when T4 shifts to the left, the critical temperature Tnr at which the thermal runaway occurs decreases.

[0065] The configuration and effects of the present embodiment are summarized below.

[0066] As shown in FIG. 5, the control device 70 repeatedly performs a predetermined series of controls (S1 to S5). In that series of controls, when self-heating of the sample Sp is detected in S3, while attempting to converge the self-heating by cooling the sample Sp by the cooling device 60, in S4, it is controlled to a pseudo-adiabatic state and observed over time. The evaluation device 80 evaluates, as the critical temperature Tnr at which the sample Sp will undergo thermal runaway even with cooling by the cooling device 60, the temperature of the sample Sp in which self-heating did not converge during the repetition of that series of controls (S1 to S5).

[0067] Therefore, by mimicking the configuration such as the arrangement and cooling rate of the cooling device 60 shown in FIG. 1 for the actual cooling means, the critical temperature Tnr at which the sample Sp will undergo thermal runaway can be evaluated even if such cooling means is present.

[0068] The evaluation result can be fed back to the design of the IPU. Specifically, for example, when opening the relief valve of the battery cell and lowering the temperature of the battery cell with the latent heat of vaporization of the electrolyte, it becomes possible to know how much it can be lowered.

[0069] Furthermore, since the sample Sp is cooled by the cooling device 60, the temperature rise of the sample Sp due to the self-heating of the sample Sp can be suppressed accordingly. Therefore, the load on the surrounding heating device 20 for maintaining the pseudo-adiabatic state can be reduced accordingly.

[0070] As shown in FIG. 1, the heating safety evaluation device 100 includes not only the cooling device 60 but also the heating device 50. Thereby, the temperature distribution around the sample Sp can be more accurately simulated to the actual temperature distribution.

[0071] As shown in FIG. 2, the cooling device 60 includes a Peltier element Pc for cooling as an element having a heat absorption surface and a heat generation surface. The sample Sp is cooled by the heat absorption surface of the Peltier element Pc for cooling. Therefore, the heat balance by the cooling device 60 in the system container 10 shown in FIG. 1 can be made zero.

[0072] The detection limit of the temperature increase rate by the first sensor 41 shown in FIG. 1 is 0.02 ° C. / min. In the case below the detection limit, by assuming that the self-heating has converged, the evaluation test can be performed with the maximum accuracy.

[0073] As shown in FIG. 2, the cooling device 60 includes a Peltier element Pc for cooling that cools the sample Sp by a heat absorption surface, and a cooling circuit Cc that supplies power to the Peltier element Pc for cooling. The control device 70 controls the cooling device 60 by controlling the cooling circuit Cc. Therefore, the cooling rate Cr by the cooling device 60 can be quantitatively controlled.

[0074] As shown in FIG. 2, the heating device 50 includes a Peltier element Ph for heating that heats the sample Sp by a heat generation surface, and a heating circuit Ch that supplies power to the Peltier element Ph for heating. The control device 70 controls the heating device 50 by controlling the heating circuit Ch. Therefore, the heating rate by the heating device 50 can be quantitatively controlled.

[0075] As shown in FIGS. 3 and 4, a plurality of Peltier elements Ph and Pc are installed on the sample Sp. By controlling such a plurality of Peltier elements Ph and Pc, the temperature and temperature distribution of the sample Sp can be accurately controlled. Therefore, it is possible to more accurately simulate the actual state.

[0076] As shown in FIGS. 3 and 4, a predetermined portion of the sample Sp is heated by the heat generating surface of the heating Peltier element Ph. Other portions of the sample Sp are cooled by the heat absorbing surface of the cooling Peltier element Pc. Thus, both heating and cooling of the sample Sp can be performed by the plurality of Peltier elements Ph and Pc.

[0077] As shown in FIG. 3, if the sample container 30 is in the shape of a hexahedron, it is easy to conduct a test imitating, for example, the housing of a hexahedron-shaped IPU. Further, as shown in FIG. 4, if the sample container 30 is in the shape of a cylinder, it is easy to conduct a test imitating, for example, the housing of a cylinder-shaped IPU.

[0078] [Other Embodiments] The embodiments shown above can be modified as follows, for example. The cooling device 60 shown in FIG. 2 may cool the sample Sp by means other than the Peltier element, such as an air cooling device or a water cooling device. The heating device 50 may heat the sample Sp by means other than the Peltier element, such as various heating elements. If the temperature distribution of the sample Sp can be accurately simulated to the actual temperature distribution even without the heating device 50 shown in FIG. 1, the heating device 50 may be omitted.

Description of Reference Numerals

[0079] 10 System container 20 Surrounding heating device 30 Sample container 41 First sensor 42 Second sensor 50 Heating device 60 Cooling device 70 Control device 80 Evaluation device 100 Heating safety evaluation device Ta Surface temperature of the sample container Tb Peripheral temperature of the sample container Ch Heating circuit Cc Cooling circuit Ph Heating Peltier element (Peltier element) Peltier element for PC cooling (Peltier element) Sp sample Self-heating rate of the SHr sample Cooling rate of the Cr sample Critical temperature at which the Tnr sample undergoes thermal runaway

Claims

1. A sensor for detecting self-heating of a sample, A surrounding heating device configured to be able to heat the periphery of the sample, A heating safety evaluation device comprising: A cooling device configured to be able to cool the sample, A control device that repeatedly performs a predetermined series of controls, The series of controls is a control that heats the sample, and then, when the self-heating is detected by the sensor, attempts to converge the self-heating by cooling the sample by the cooling device, while making a pseudo-adiabatic state by heating with the surrounding heating device, The pseudo-adiabatic state is a state in which the heat balance between the sample cooled by the cooling device and its surroundings becomes zero, A heating safety evaluation device that, during the repetition of the series of controls, evaluates the temperature of the sample in which the self-heating has not converged as the critical temperature at which the sample will thermally runaway even by cooling by the cooling device.

2. Comprising a heating device configured to be able to heat the sample, The series of controls is a control that heats the sample, and then, when the self-heating is detected by the sensor, performs cooling of the sample by the cooling device and heating of the sample by the heating device, while making a pseudo-adiabatic state by heating with the surrounding heating device, The pseudo-adiabatic state is a state in which the heat balance between the sample cooled by the cooling device and heated by the heating device and its surroundings becomes zero, The heating safety evaluation device according to claim 1.

3. The cooling device includes an element having a heat absorption surface and a heat generation surface, and cools the sample by the heat absorption surface, The heating safety evaluation device according to claim 1 or 2.

4. When the temperature rise rate of the sample is 0.02 °C / min or less, the control device regards that the self-heating has converged. The heating safety evaluation device according to claim 1 or 2.

5. The cooling device includes a cooling Peltier element that cools the sample by the heat absorption surface, and a cooling circuit that supplies power to the cooling Peltier element. The control device controls the cooling device by controlling the cooling circuit. The heating safety evaluation device according to claim 3.

6. The heating device includes a heating Peltier element that heats the sample by the heat generation surface, and a heating circuit that supplies power to the heating Peltier element. The control device controls the heating device by controlling the heating circuit. The heating safety evaluation device according to claim 2.

7. A plurality of Peltier elements are installed for the sample. The heating safety evaluation device according to claim 1 or 2.

8. The heating device includes a heating Peltier element that heats the sample by the heat generation surface, and a heating circuit that supplies power to the heating Peltier element. The cooling device includes a cooling Peltier element that cools the sample by the heat absorption surface, and a cooling circuit that supplies power to the cooling Peltier element. A predetermined part of the sample is heated by the heat generation surface of the heating Peltier element. Another part of the sample is cooled by the heat absorption surface of the cooling Peltier element. The heating safety evaluation device according to claim 2.

9. The heating safety evaluation device further includes a sample container for storing the sample. The sample container is in the shape of a hexahedron. The heating safety evaluation device according to claim 1 or 2.

10. Further comprising a sample container for storing the sample, The sample container is cylindrical, The heating safety evaluation device according to claim 1 or 2.

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