Detection device

Abstract

The present invention provides a detection device that allows a user or the like to easily monitor whether the thermal insulation performance of an object such as a battery pack is maintained. The control device (20) includes: a thermal insulation performance deriving unit (22) that derives a thermal insulation performance value as an evaluation value of the thermal insulation performance based on a temperature change of a battery detected by a battery temperature sensor (14) and an ambient temperature detected by an ambient temperature sensor (9) during a predetermined period when a vehicle is stopped; a determination unit (23) that determines whether a reduction in thermal insulation performance has occurred based on the thermal insulation performance value derived by the thermal insulation performance deriving unit (22) and a predetermined reference value; and an output unit (25) that outputs detection information indicating that a reduction in thermal insulation performance has occurred when the determination unit (23) determines that a reduction in thermal insulation performance has occurred.

Description

Technical Field

[0001] The present invention relates to a detection device for detecting a decrease in the thermal insulation performance of an object whose outer side is surrounded by a thermal insulation material. Background Art

[0002] In recent years, initiatives to achieve a low-carbon or decarbonized society have been actively pursued as concrete measures to combat global climate change. In the automotive sector, there is also a strong demand to reduce CO2 emissions, and the electrification of drive sources is rapidly advancing. Specifically, the development of vehicles (hereinafter referred to as "electric vehicles") that include an electric motor as a drive source and a battery as a power source capable of supplying electricity to the electric motor is progressing, such as electric vehicles (EVs) and hybrid electric vehicles (HEVs).

[0003] To prevent degradation, batteries can be used while being maintained within an appropriate temperature range by a temperature control system. For example, Patent Document 1 below discloses a technique for heating or maintaining the temperature of sodium-sulfur batteries placed within an insulated container by blowing heated air into the container using a fan. This heated air is extracted through a heat exchanger from waste heat from a combined heat and power system, such as a fuel cell.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2003-317799 Summary of the Invention

[0007] Problems to be solved by the invention

[0008] Objects surrounded by insulating material, such as battery packs containing batteries in an insulating casing, may experience a decrease in their insulation performance during use. If a user continues to use the object without noticing the decrease, it may become difficult to maintain the object's temperature within an appropriate range, or excessive energy may be required to do so. To prevent this, it is desirable for users to be able to easily monitor whether the object's insulation performance is being maintained.

[0009] The present invention provides a detection device capable of easily monitoring whether the thermal insulation performance of an object surrounded by a thermal insulation material is maintained.

[0010] Solutions to Problems

[0011] The present invention is a detection device for detecting a decrease in the thermal insulation performance of a battery pack mounted on an electric vehicle, wherein:

[0012] The battery pack is constructed by housing batteries and a battery temperature sensor capable of detecting the temperature of the batteries in a heat-insulating casing.

[0013] The electric vehicle includes an ambient temperature sensor outside the battery pack capable of detecting the ambient temperature around the electric vehicle.

[0014] The detection device comprises:

[0015] a heat insulation performance deriving unit configured to derive a heat insulation performance value as an evaluation value of the heat insulation performance based on a temperature change of the battery detected by the battery temperature sensor and an ambient temperature detected by the ambient temperature sensor during a predetermined period when the electric vehicle is stopped;

[0016] a determination unit that determines whether or not the thermal insulation performance has been degraded based on the thermal insulation performance value derived by the thermal insulation performance deriving unit and a predetermined reference value; and

[0017] An output unit outputs detection information indicating that the thermal insulation performance has been degraded, when the determination unit determines that the thermal insulation performance has been degraded.

[0018] Effects of the Invention

[0019] According to the present invention, it is possible to provide a detection device that can easily monitor whether the thermal insulation performance of an object surrounded by a thermal insulation material is maintained. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 1 is a schematic configuration diagram of a vehicle 1 equipped with a control device 20 as one embodiment of a detection device according to the present invention.

[0021] Figure 2 It is a schematic structural diagram of the battery pack 10 mounted on the vehicle 1 .

[0022] Figure 3 2 is a block diagram showing the functional configuration of the control device 20 .

[0023] Figure 4 1 is a diagram showing an example of determining whether or not the thermal insulation performance of the battery pack 10 has deteriorated.

[0024] Figure 5 This is a flowchart showing an example of processing performed by the control device 20.

[0025] Description of reference numerals:

[0026] 1 Vehicle (electric vehicle)

[0027] 4 Carriage

[0028] 9 Ambient temperature sensor

[0029] 10 battery pack

[0030] 11 Housing

[0031] 12 Batteries

[0032] 14 Battery temperature sensor

[0033] 20 Control device (detection device)

[0034] 22 Thermal insulation performance export section

[0035] 23 Judgment Department

[0036] 24 Presumption Department

[0037] 25 Output

[0038] 30 Notification Department. DETAILED DESCRIPTION

[0039] Hereinafter, an embodiment of the detection device of the present invention will be described in detail with reference to the accompanying drawings. The embodiment described below is an example of a case where the detection device of the present invention is applied to a control device that detects a reduction in the thermal insulation performance of a battery pack mounted on an electric vehicle. In addition, in the following description, front and back, up and down, left and right refer to directions when viewed from the perspective of an operator of an electric vehicle (hereinafter also referred to as a "vehicle") equipped with a control device as an example of the detection device of the present invention. In addition, in the accompanying drawings, the front of the vehicle is represented as Fr, the rear as Rr, the top as U, the bottom as D, the right as R, and the left as L.

[0040] [vehicle]

[0041] like Figure 1 As shown, a vehicle 1 is divided into a passenger compartment 4, a trunk 5, and a front compartment 6 in front of the compartments 4 and 5 by a floor 2 and a dash panel 3. Front seats 7 and rear seats 8 are located within the passenger compartment 4, and a drive motor MOT, serving as a driving source for the left and right front wheels FW, is located within the front compartment 6. A battery pack 10 including a battery (illustrated as "BAT") 12 is located below the passenger compartment 4. This battery 12 serves as a power source capable of supplying power to the drive motor MOT.

[0042] The vehicle 1 is an electric vehicle, such as an electric car, that travels by driving a driving motor MOT using the power from a battery 12. Alternatively, the power from the battery BAT may be converted by a power conversion device (not shown) (e.g., an inverter or a DC / DC converter) into a predetermined power suitable for driving the driving motor MOT, and then supplied to the driving motor MOT.

[0043] Furthermore, an ambient temperature sensor 9 is provided within the front compartment 6. This ambient temperature sensor 9 is capable of detecting the ambient temperature surrounding the vehicle 1. For example, the ambient temperature sensor 9 detects the ambient air temperature surrounding the vehicle 1 as the ambient temperature at a predetermined timing and transmits a detection signal indicating the detected ambient temperature to the control device 20, described later. For example, an in-vehicle network such as a CAN (Controller Area Network) can be used for communication between the ambient temperature sensor 9 and the control device 20.

[0044] [Battery Pack]

[0045] Next, the battery pack 10 will be described. Figure 2 As shown, battery pack 10 is constructed by housing batteries 12 and a battery temperature sensor 14 capable of detecting the temperature of battery 12 within a heat-insulating housing 11. Typically, when battery pack 10 is mounted on vehicle 1, the interior of housing 11 forms a closed space, and battery 12 and battery temperature sensor 14 are disposed within this closed space.

[0046] The battery 12 is configured to output a high voltage of, for example, 100 to 200 V by connecting a plurality of battery modules 13 in series. Each battery module 13 is configured by connecting a plurality of storage cells in series, such as lithium-ion batteries or nickel-metal hydride batteries.

[0047] A plurality of battery temperature sensors 14 are provided corresponding to each battery module 13. Each battery temperature sensor 14 detects the temperature of the corresponding battery module 13 at a predetermined timing and transmits a detection signal indicating the detected temperature to the control device 20. Communication between the battery temperature sensors 14 and the control device 20 can utilize, for example, the aforementioned in-vehicle network.

[0048] The control device 20, an example of a detection device according to the present invention, detects a decrease in the thermal insulation performance of the battery pack 10 based on changes in the temperature of the battery BAT detected by the battery temperature sensor 14 and the ambient temperature detected by the ambient temperature sensor 9. The control device 20 can be implemented, for example, by an ECU (Electronic Control Unit), which includes a processor for performing various calculations, a storage device for storing various information, and input / output devices for controlling the input and output of data between the control device 20 and its external environment. Furthermore, the control device 20 can be implemented by a single ECU or by the coordinated operation of multiple ECUs.

[0049] In the present embodiment, the control device 20 is provided in the battery pack 10 , but the present invention is not limited thereto and the control device 20 may be provided outside the battery pack 10 (for example, in the front chamber 6 ).

[0050] [Control device]

[0051] Next, an example of the functional structure of the control device 20 will be described. Figure 3 As shown, the control device 20 includes an acquisition unit 21 , a thermal insulation performance derivation unit 22 , a determination unit 23 , an estimation unit 24 , and an output unit 25 .

[0052] The acquisition unit 21 acquires ambient temperature information indicating the ambient temperature detected by the ambient temperature sensor 9, and battery temperature information indicating the temperature of the battery module 13 (i.e., the battery 12) detected by the battery temperature sensor 14. The ambient temperature information can be acquired from the detection signal received by the control device 20 from the ambient temperature sensor 9. Furthermore, the battery temperature information can be acquired from the detection signal received by the control device 20 from the battery temperature sensor 14.

[0053] For example, when acquiring the ambient temperature information and the battery temperature information, the acquiring unit 21 stores the acquired information in association with information indicating the time when the information was acquired in a storage device or the like of the control device 20. Furthermore, the information indicating the time can be acquired from, for example, an RTC (Real-Time Clock) (not shown) provided in the control device 20.

[0054] The acquisition unit 21 acquires battery temperature information indicating the temperature of the battery module 13 detected by the battery temperature sensor 14 when the ignition power of the vehicle 1 is turned off. For example, upon receiving an IG-off signal from another control unit (not shown) indicating that the ignition power of the vehicle 1 has been turned off, the control unit 20 transmits a detection request to each battery temperature sensor 14. In response to the detection request, each battery temperature sensor 14 detects the temperature of the corresponding battery module 13 and transmits a detection signal indicating the detected temperature to the control unit 20. Thus, the acquisition unit 21 can acquire battery temperature information indicating the temperature of the battery module 13 detected by the battery temperature sensor 14 when the ignition power of the vehicle 1 is turned off.

[0055] Furthermore, the acquisition unit 21 acquires battery temperature information indicating the temperature of the battery module 13 detected by the battery temperature sensor 14 when a specified period (e.g., 1 hour) has passed after the ignition power of the vehicle 1 has been disconnected. For example, when a specified period has passed after the ignition power of the vehicle 1 has been disconnected, the control device 20 again sends a detection request to each battery temperature sensor 14. Each battery temperature sensor 14 detects the temperature of the corresponding battery module 13 in accordance with the detection request, and sends a detection signal indicating the detected temperature to the control device 20. Thus, the acquisition unit 21 can acquire battery temperature information indicating the temperature of the battery module 13 detected by the battery temperature sensor 14 when a specified period has passed after the ignition power of the vehicle 1 has been disconnected. In addition, the above-mentioned specified period is pre-set in the control device 20 by the manufacturer of the control device 20, etc.

[0056] Furthermore, the control device 20 also transmits a detection request to the ambient temperature sensor 9, for example, at a predetermined timing. In response to the detection request, the ambient temperature sensor 9 detects the ambient temperature surrounding the vehicle 1 and transmits a detection signal indicating the detected ambient temperature to the control device 20. This allows the acquisition unit 21 to acquire ambient temperature information indicating the ambient temperature detected by the ambient temperature sensor 9 at a predetermined timing. The timing for causing the ambient temperature sensor 9 to detect the ambient temperature may be when the ignition power of the vehicle 1 is turned off, when a predetermined period has elapsed since the ignition power was turned off, or at any other time within the predetermined period.

[0057] The thermal insulation performance deriving unit 22 derives a thermal insulation performance value as an evaluation value of the thermal insulation performance of the battery pack 10 based on the change in the temperature of the battery 12 detected by the battery temperature sensor 14 and the ambient temperature detected by the ambient temperature sensor 9 during the above-mentioned specified period when the ignition power of the vehicle 1 is disconnected (i.e., the vehicle 1 is stopped).

[0058] Specifically, here, when the length of the specified period is set to t, the ambient temperature is set to Ta, the temperature of the battery 12 at the beginning of the specified period is set to T0, the temperature of the battery 12 after the specified period is set to T1, and the thermal insulation performance value is set to τ, the thermal insulation performance derivation unit 22 derives the thermal insulation performance value τ through the following formula (1).

[0059]

[0060] As T0 in the above formula (1), for example, the average value or median value of the temperature of each battery module 13 when the ignition power of the vehicle 1 is turned off can be used. In addition, as T1 in the above formula (1), for example, the average value or median value of the temperature of each battery module 13 when a predetermined period of time has passed after the ignition power of the vehicle 1 is turned off can be used.

[0061] As Ta in the above-mentioned formula (1), for example, any of the following can be used: the ambient temperature when the ignition power of vehicle 1 is turned off; the ambient temperature after a predetermined period has elapsed since the ignition power of vehicle 1 was turned off; and the ambient temperature at any time within the predetermined period. Furthermore, the average or median value of the ambient temperatures at these respective times can also be used as Ta in the above-mentioned formula (1). That is, because the ambient temperature fluctuates less than the temperature of battery BAT, the thermal insulation performance value τ derived from the above-mentioned formula (1) remains substantially unchanged regardless of which of the above-mentioned ambient temperatures is used for Ta.

[0062] The determination unit 23 determines whether the thermal insulation performance of the battery pack 10 has deteriorated based on the thermal insulation performance value τ derived by the thermal insulation performance deriving unit 22 and a predetermined reference value that serves as a reference for determining whether the thermal insulation performance of the battery pack 10 has deteriorated. Figure 4 As indicated by the solid line of reference numeral 401 in FIG, the reference value is determined in consideration of the reduction in heat insulation performance associated with aging of the battery pack 10 .

[0063] For example, when the difference between the thermal insulation performance value τ and the reference value is greater than a predetermined threshold, the determination unit 23 determines that the thermal insulation performance of the battery pack 10 has deteriorated. Specifically, Figure 4 A dotted line 402 in FIG. 4 represents a value obtained by subtracting the threshold value from the reference value. When the thermal insulation performance value τ is lower than the dotted line 402 , the determination unit 23 determines that a decrease in thermal insulation performance has occurred.

[0064] Thus, by having the determination unit 23 determine that a decrease in thermal insulation performance has occurred based on a certain degree of difference between the thermal insulation performance value τ and a reference value determined in consideration of the decrease in thermal insulation performance associated with aging of the battery pack 10, the control device 20 can accurately detect abnormal decreases in thermal insulation performance due to factors other than aging (e.g., damage to the housing 11). In other words, even if there is a decrease in thermal insulation performance associated with aging of the battery pack 10, the determination unit 23 can be prevented from determining that a decrease in thermal insulation performance has occurred in the battery pack 10 based on such a generally conceivable decrease in thermal insulation performance.

[0065] The reference value is preset in the control device 20, for example, by the manufacturer of the control device 20. Alternatively, the reference value may be stored in another computer, such as a server device, located outside the vehicle 1. If the reference value is stored in another computer, the control device 20 may access the computer storing the reference value via a predetermined network such as the Internet and appropriately refer to the reference value stored in the computer.

[0066] The computer storing the reference value may be, for example, a server device configured to collect market data. Here, the market data may be, for example, data indicating how the thermal insulation performance of battery packs of the same type as battery pack 10 changes over time in vehicles equipped with such battery packs. Specifically, by determining the reference value based on this market data, the server device can set a reference value that appropriately accounts for the reduction in thermal insulation performance associated with the aging of battery pack 10. Furthermore, determination unit 23 uses the reference value determined in this manner, taking into account the market data, to determine whether a reduction in the thermal insulation performance of battery pack 10 has occurred. This allows control device 20 to accurately detect abnormal reductions in thermal insulation performance due to factors other than aging.

[0067] When the determination unit 23 determines that the heat insulation performance has deteriorated, the estimation unit 24 estimates an abnormal location in the battery pack 10 based on the temperature detected by each battery temperature sensor 14 .

[0068] For example, in the first case where only one of the temperatures detected by the battery temperature sensors 14 exceeds a predetermined value, the estimation unit 24 estimates that the battery temperature sensor 14 detecting that temperature is an abnormal location. The predetermined value may be, for example, the average of the temperatures detected by the battery temperature sensors 14 + n[°C] (where n is a natural number greater than or equal to 1, such as 10).

[0069] On the other hand, in a second case other than the first case, the estimating unit 24 estimates a portion of the battery pack 10 that is causing a decrease in thermal insulation performance as an abnormal portion based on the temperatures detected by each battery temperature sensor 14. As a specific example, in the second case, if the change in temperature detected by the battery temperature sensor 14 located on the left side is greater than the change in temperature detected by the battery temperature sensor 14 located on the right side, the estimating unit 24 estimates the left side portion of the casing 11 as the abnormal portion.

[0070] The output unit 25 outputs detection information indicating that the thermal insulation performance has been reduced when the determination unit 23 determines that the thermal insulation performance has been reduced. In addition, the output unit 25 outputs abnormality location information indicating the abnormality location when the estimation unit 24 estimates an abnormality location.

[0071] The output unit 25 is configured, for example, to output detection information and abnormal location information to a notification unit 30 configured to notify a user (e.g., the operator) of the vehicle 1. Specific examples of the notification unit 30 include a display, a speaker, and a light display including a warning light provided on the vehicle 1. By outputting the detection information and abnormal location information to the notification unit 30, the notification unit 30 can notify the user, etc., of a decrease in the thermal insulation performance of the battery pack 10 and the abnormal location in the battery pack 10 that is causing the decrease in thermal insulation performance.

[0072] The acquisition unit 21 , the thermal insulation performance derivation unit 22 , the determination unit 23 , the estimation unit 24 , and the output unit 25 can realize their functions by, for example, the processor of the control device 20 executing a program pre-stored in a storage device.

[0073] [An example of processing performed by the control device]

[0074] Next, an example of the processing performed by the control device 20 will be described. Figure 5 As shown, the control device 20 first determines whether the ignition power of the vehicle 1 is turned off (step S1). If the ignition power of the vehicle 1 is not turned off (step S1: No), the control device 20 repeats the process of step S1 until the ignition power of the vehicle 1 is turned off.

[0075] Then, when the ignition power of the vehicle 1 is turned off (step S1 : YES), the control device 20 acquires battery temperature information indicating the temperature of the battery module 13 when the ignition power of the vehicle 1 is turned off (step S2 ).

[0076] Next, the control device 20 determines whether a predetermined period has passed since the ignition power of the vehicle 1 was turned off (step S3). If the predetermined period has not passed since the ignition power of the vehicle 1 was turned off (step S3: No), the control device 20 waits until the predetermined period has passed.

[0077] Then, when a predetermined period has passed since the ignition power of the vehicle 1 was turned off (step S3: YES), the control device 20 obtains battery temperature information indicating the temperature of the battery module 13 after the predetermined period has passed (step S4) and obtains ambient temperature information indicating the ambient temperature (step S5).

[0078] Next, the control device 20 uses the above formula (1) to derive the thermal insulation performance value τ based on the battery temperature information obtained in steps S2 and S4, and the ambient temperature information obtained in step S5 (step S6). Then, the control device 20 compares the thermal insulation performance value τ derived in step S6 with the reference value (step S7) and determines whether the difference between the thermal insulation performance value τ and the reference value is greater than a threshold value (step S8). If the difference between the thermal insulation performance value τ and the reference value is less than or equal to the threshold value (step S8: No), the control device 20 ends. Figure 5 A series of processing shown.

[0079] On the other hand, if the difference between the thermal insulation performance value τ and the reference value is greater than the threshold value (step S8: YES), the control device 20 outputs detection information indicating that a decrease in the thermal insulation performance of the battery pack 10 has occurred to the notification unit 30 (step S9). The control device 20 then executes abnormality location estimation processing to estimate the location of the abnormality (step S10). In this abnormality location estimation processing, for example, as described above, in the first case where the temperature detected by only one battery temperature sensor 14 is prominent, the battery temperature sensor 14 that detected that temperature is estimated to be the abnormal location. Furthermore, in a second case other than the first case, the damaged location of the casing 11 is estimated based on the temperatures detected by each battery temperature sensor 14.

[0080] Then, the control device 20 outputs abnormality portion information indicating the abnormality portion estimated by the abnormality portion estimation process in step S10 to the notification unit 30 (step S11), and ends the process. Figure 5 A series of processing shown.

[0081] As described above, the control device 20 derives the thermal insulation performance value τ based on the temperature change of the battery 12 and the ambient temperature. If it is determined based on the derived thermal insulation performance value τ and the reference value that the thermal insulation performance of the battery pack 10 has degraded, the control device 20 outputs detection information indicating that a degraded thermal insulation performance has occurred. This allows users and others to easily monitor whether the thermal insulation performance of the battery pack 10 is being maintained.

[0082] Furthermore, when the difference between the thermal insulation performance value τ and the reference value is greater than a threshold, the control device 20 determines that the thermal insulation performance of the battery pack 10 has degraded.

[0083] Furthermore, the control device 20 determines whether a decrease in the thermal insulation performance of the battery pack 10 has occurred based on a reference value determined in consideration of a decrease in thermal insulation performance associated with aging of the battery pack 10. This allows for highly accurate detection of abnormal decreases in thermal insulation performance due to factors other than aging.

[0084] Furthermore, if the control device 20 determines that the thermal insulation performance of the battery pack 10 has degraded, it executes abnormality location estimation processing to estimate the abnormal location in the battery pack 10 and outputs abnormality location information indicating the estimated abnormal location. This allows notification of the abnormal location to the user of the vehicle 1 , etc.

[0085] Furthermore, in this embodiment, when only one of the temperatures detected by the battery temperature sensors 14 exceeds a predetermined value (a first case), the battery temperature sensor 14 detecting that temperature is estimated as an abnormal location. In other cases (a second case), the location in the battery pack 10 causing the reduction in thermal insulation performance is estimated as an abnormal location based on the temperatures detected by the battery temperature sensors 14. This allows notification of the appropriate location as an abnormal location to the user of the vehicle 1, etc.

[0086] Furthermore, in this embodiment, the battery pack 10 is positioned below the interior 4 of the vehicle 1, enabling efficient use of the limited space within the vehicle 1 for placement of the battery pack 10. On the other hand, when the battery pack 10 is positioned below the interior of the vehicle 1, it can be difficult to visually detect damage to the battery pack 10 (e.g., damage to the housing 11). However, according to this embodiment, when thermal insulation performance degrades, the control device 20 outputs detection information indicating this, as well as abnormality location information indicating the estimated abnormality location. This allows users, etc., to easily monitor whether the thermal insulation performance of the battery pack 10 has degraded due to damage, etc., and, if so, the location of the abnormality location.

[0087] As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, and it can make deformation|transformation, improvement, etc. as needed.

[0088] For example, in the above embodiment, the battery temperature sensors 14 are provided for all of the plurality of battery modules 13, but they may be provided for at least two of the plurality of battery modules 13. With this configuration, it is possible to estimate an abnormal location in the battery pack 10 based on the temperatures detected by at least two of the battery temperature sensors 14.

[0089] Furthermore, in the above embodiment, an example in which the vehicle 1 is an electric vehicle has been described. However, the vehicle 1 may be a hybrid electric vehicle or a fuel cell vehicle.

[0090] Furthermore, in the above embodiment, the object, whose exterior is surrounded by heat-insulating material, is described as a battery pack 10 comprising batteries 12 housed in a heat-insulating housing 11. However, the present invention is not limited to this. Any object having heat-insulating material on the exterior and a closed space on the interior may be used, and may include, for example, a residence, a warehouse, or the vehicle 1 (the cabin 4) itself. The object includes a first temperature sensor within the closed space capable of detecting the temperature within the closed space, and a second temperature sensor outside the closed space capable of detecting the temperature outside the closed space, such as the aforementioned ambient temperature sensor 9 and battery temperature sensor 14.

[0091] In this specification, at least the following matters are described: In addition, although corresponding components and the like in the above-mentioned embodiment are shown in brackets, the present invention is not limited thereto.

[0092] (1) A detection device (control device 20) for detecting a decrease in thermal insulation performance of a battery pack (battery pack 10) mounted on an electric vehicle (vehicle 1), wherein:

[0093] The battery pack is constructed by housing a battery (battery 12) and a battery temperature sensor (battery temperature sensor 14) capable of detecting the temperature of the battery in a housing (housing 11) having heat insulation properties.

[0094] The electric vehicle includes an ambient temperature sensor (ambient temperature sensor 9) outside the battery pack that can detect the ambient temperature around the electric vehicle.

[0095] The detection device comprises:

[0096] a thermal insulation performance deriving unit (thermal insulation performance deriving unit 22) for deriving a thermal insulation performance value (thermal insulation performance value τ) as an evaluation value of the thermal insulation performance based on a temperature change of the battery detected by the battery temperature sensor and an ambient temperature detected by the ambient temperature sensor during a predetermined period when the electric vehicle is stopped;

[0097] a determination unit (determination unit 23) that determines whether the thermal insulation performance has been degraded based on the thermal insulation performance value derived by the thermal insulation performance deriving unit and a predetermined reference value; and

[0098] The output unit (output unit 25 ) outputs detection information indicating that the thermal insulation performance has been degraded, when the determination unit determines that the thermal insulation performance has been degraded.

[0099] Assume that the thermal insulation performance of a battery pack mounted on an electric vehicle degrades during use. According to (1), a thermal insulation performance value can be derived based on the temperature change of the battery and the ambient temperature. If a deterioration in thermal insulation performance is determined based on the derived thermal insulation performance value and a reference value, detection information indicating that a deterioration in thermal insulation performance has occurred is output. This allows users and others to easily monitor whether the thermal insulation performance of the battery pack is maintained.

[0100] (2) The detection device according to (1), wherein

[0101] The determination unit determines that the thermal insulation performance has deteriorated when the difference between the thermal insulation performance value and the reference value is larger than a predetermined threshold value.

[0102] According to (2), when the difference between the thermal insulation performance value and the reference value is larger than a threshold value, it can be determined that the thermal insulation performance has been degraded. Thus, the occurrence of thermal insulation performance degradation can be detected with high accuracy.

[0103] (3) The detection device according to (1) or (2), wherein:

[0104] The reference value is determined in consideration of a decrease in the heat insulation performance due to aging of the battery pack.

[0105] According to (3), whether or not a reduction in thermal insulation performance has occurred can be determined based on a reference value determined in consideration of the reduction in thermal insulation performance associated with aging of the battery pack. This makes it possible to detect abnormal reductions in thermal insulation performance due to factors other than aging (e.g., damage to the housing).

[0106] (4) The detection device according to (1) or (2), wherein:

[0107] The reference value is determined by a server device configured to collect market data based on the market data.

[0108] The determination unit determines whether the thermal insulation performance has been degraded based on the reference value acquired from the server device.

[0109] According to (4), whether or not the thermal insulation performance has been reduced can be determined based on the reference value determined in consideration of market data. This makes it possible to accurately detect the reduction in thermal insulation performance.

[0110] (5) The detection device according to any one of (1) to (4), wherein

[0111] The battery pack is arranged below the vehicle interior (vehicle interior 4 ) of the electric vehicle.

[0112] By arranging the battery pack below the cabin of an electric vehicle, the limited space of the electric vehicle can be effectively utilized to arrange the battery pack. On the other hand, when the battery pack is arranged below the cabin of an electric vehicle, it may be difficult to visually confirm damage to the battery pack. According to (5), even if the battery pack is arranged below the cabin of an electric vehicle, the user can easily monitor whether the thermal insulation performance has been reduced due to damage to the battery pack.

[0113] (6) The detection device according to any one of (1) to (5), wherein

[0114] The output unit outputs the detection information to a notification unit (notification unit 30 ) configured to be able to notify a user.

[0115] According to (6), the detection information is output to the notification unit configured to be able to notify the user, whereby the notification unit can notify the user based on the detection information.

[0116] (7) The detection device according to any one of (1) to (6), wherein

[0117] When the length of the predetermined period is t, the ambient temperature is Ta, the temperature of the battery at the start of the predetermined period is T0, the temperature of the battery after the predetermined period has elapsed is T1, and the thermal insulation performance value is τ, the thermal insulation performance deriving unit derives the thermal insulation performance value using the following formula (1):

[0118]

[0119] According to (7), the thermal insulation performance value can be appropriately derived based on the length of the predetermined period, the ambient temperature, and the temperature of the battery.

[0120] (8) The detection device according to any one of (1) to (7), wherein

[0121] The battery is composed of a plurality of battery modules.

[0122] The battery temperature sensor is respectively provided corresponding to at least two of the plurality of battery modules.

[0123] The detection device further includes an estimating unit (estimating unit 24) for estimating an abnormal portion in the battery pack based on the temperature detected by each battery temperature sensor when the determining unit determines that the heat insulation performance has deteriorated.

[0124] The output unit further outputs abnormality site information indicating the abnormality site estimated by the estimating unit.

[0125] According to (8), when it is determined that the thermal insulation performance has deteriorated, the abnormal location in the battery pack can be estimated based on the temperature detected by each battery temperature sensor, and abnormal location information indicating the estimated abnormal location can be output. This allows the user and the like to be notified of the abnormal location.

[0126] (9) The detection device according to (8), wherein

[0127] The estimating unit estimates that, in a first case where only one of the temperatures detected by the battery temperature sensors exceeds a predetermined value, the battery temperature sensor detecting the temperature is the abnormal portion.

[0128] In a second case other than the first case, the estimating unit estimates a portion of the battery pack that causes the reduction in the heat insulation performance as the abnormal portion based on the temperature detected by each battery temperature sensor.

[0129] According to (9), it is possible to notify a user or the like of an appropriate portion as an abnormal portion.

Claims

1. A detection device for detecting a decrease in thermal insulation performance of a battery pack mounted on an electric vehicle, wherein: The battery pack is constructed by housing batteries and a battery temperature sensor capable of detecting the temperature of the batteries in a heat-insulating casing. The electric vehicle includes an ambient temperature sensor outside the battery pack capable of detecting the ambient temperature around the electric vehicle. The detection device comprises: a heat insulation performance deriving unit configured to derive a heat insulation performance value as an evaluation value of the heat insulation performance based on a temperature change of the battery detected by the battery temperature sensor and an ambient temperature detected by the ambient temperature sensor during a predetermined period when the electric vehicle is stopped; a determination unit that determines whether the thermal insulation performance has been degraded based on the thermal insulation performance value derived by the thermal insulation performance deriving unit and a predetermined reference value; as well as An output unit outputs detection information indicating that the thermal insulation performance has been degraded, when the determination unit determines that the thermal insulation performance has been degraded.

2. The detection device according to claim 1, wherein The determination unit determines that the thermal insulation performance has deteriorated when the difference between the thermal insulation performance value and the reference value is larger than a predetermined threshold value.

3. The detection device according to claim 1 or 2, wherein: The reference value is determined in consideration of a decrease in the heat insulation performance due to aging of the battery pack.

4. The detection device according to claim 1 or 2, wherein: The reference value is determined by a server device configured to collect market data based on the market data. The determination unit determines whether the thermal insulation performance has been degraded based on the reference value acquired from the server device.

5. The detection device according to claim 1 or 2, wherein: The battery pack is arranged below a vehicle cabin of the electric vehicle.

6. The detection device according to claim 1 or 2, wherein: The output unit outputs the detection information to a notification unit configured to be able to notify a user.

7. The detection device according to claim 1 or 2, wherein: When the length of the predetermined period is t, the ambient temperature is Ta, the temperature of the battery at the start of the predetermined period is T0, the temperature of the battery after the predetermined period has elapsed is T1, and the thermal insulation performance value is τ, the thermal insulation performance deriving unit derives the thermal insulation performance value using the following formula (1):

8. The detection device according to claim 1 or 2, wherein: The battery is composed of a plurality of battery modules. The battery temperature sensor is respectively provided corresponding to at least two of the plurality of battery modules. The detection device further includes an estimating unit that estimates an abnormal portion in the battery pack based on the temperature detected by each battery temperature sensor when the determining unit determines that the heat insulation performance has deteriorated. The output unit further outputs abnormality site information indicating the abnormality site estimated by the estimating unit.

9. The detection device according to claim 8, wherein: The estimating unit estimates that, in a first case where only one of the temperatures detected by the battery temperature sensors exceeds a predetermined value, the battery temperature sensor detecting the temperature is the abnormal portion. In a second case other than the first case, the estimating unit estimates a portion of the battery pack that causes the reduction in the heat insulation performance as the abnormal portion based on the temperature detected by each battery temperature sensor.

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