Inspection system

Abstract

To easily inspect etching of a battery pack.SOLUTION: An inspection system comprises: a battery pack that houses a battery mounted onto a vehicle; a suction duct that can introduce an air in an external part of the vehicle into an internal part of the battery pack to cool the battery; an exhaust duct that introduces the air in the internal part of the battery pack to the external part of the vehicle; one or a plurality of chloride ion inspection sensors that are arranged in the internal part of the battery pack, and can inspect a chloride ion; and a first control device. The first control device includes: one or a plurality of first processors; and one or a plurality of first memories connected to each first processor. Each first processor executes a processing containing an inspection of etching of the battery pack on the basis of an inspection value of each chloride ion inspection sensor.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an inspection system for inspecting corrosion of a battery pack.

Background Art

[0002] For example, Patent Document 1 discloses a fuel cell system that cools a fuel cell using a liquid refrigerant. In such a fuel cell system, impurity ions eluted from a metal pipe serving as a refrigerant flow path into ion-exchanged water as the refrigerant are detected.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, some vehicles are configured to air-cool the battery with the air outside the vehicle. When such a vehicle travels in a heavy snow area where a snow-melting agent is used, for example, air containing a large amount of chloride ions outside the vehicle is taken into the inside of the battery pack to air-cool the battery. Then, corrosion may occur in the battery pack due to the chloride ions in the air taken into the inside of the battery pack. When the battery pack corrodes, the function of protecting the battery by the battery pack deteriorates.

[0005] Therefore, an object of the present invention is to provide an inspection system capable of easily detecting corrosion of a battery pack.

Means for Solving the Problems

[0006] In order to solve the above problems, an inspection system according to an embodiment of the present invention is It houses the battery installed in the vehicle. and formed from metal materials Battery pack and An intake duct capable of drawing outside air from the vehicle into the battery pack to air-cool the battery, An exhaust duct that guides the air inside the battery pack to the outside of the vehicle, One or more chloride ion detection sensors, which are disposed inside the battery pack and capable of detecting chloride ions, First control device, Equipped with, The first control device is One or more first processors, One or more first memories connected to the first processor, It has, The aforementioned first processor, Based on the detected value of the chloride ion detection sensor, the battery pack is inspected for corrosion. Execute the process that includes this. [Effects of the Invention]

[0007] According to the present invention, corrosion of a battery pack can be easily detected. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic block diagram showing the configuration of the inspection system according to this embodiment. [Figure 2] Figure 2 is a plan view illustrating the arrangement of the chloride ion detection sensor. [Figure 3] Figure 3 is a first side perspective view illustrating the arrangement of the chloride ion detection sensor. [Figure 4] Figure 4 is a second side perspective view illustrating the arrangement of the chloride ion detection sensor. [Figure 5] Figure 5 is a circuit diagram illustrating a method for detecting chloride ions using a chloride ion detection sensor. [Figure 6] Figure 6 illustrates the characteristics of the chloride ion detection sensor. [Figure 7] FIG. 7 is a flowchart for explaining the operation flow of the first inspection unit in the vehicle. [Figure 8] FIG. 8 is a flowchart for explaining the inspection flow of the inspection operator. [Figure 9] FIG. 9 is a diagram for explaining the flow of the hysteresis confirmation process. [Figure 10] FIG. 10 is a flowchart showing an example of performing the hysteresis confirmation process only once. [Figure 11] FIG. 11 is a flowchart showing an example when only the inspection by the first inspection unit is performed.

MODE FOR CARRYING OUT THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The specific dimensions, materials, numerical values, etc. shown in such embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same functions and configurations are denoted by the same reference numerals to omit redundant explanations, and elements not directly related to the present invention are not shown.

[0010] FIG. 1 is a schematic block diagram showing the configuration of an inspection inspection inspection system 1 according to the present embodiment. The inspection system 1 includes a vehicle 10 and an external inspection device 12.

[0011] The vehicle 10 is, for example, an electric vehicle or a hybrid electric vehicle, and includes a motor as a driving source for traveling. The vehicle 10 includes a battery 20 and a battery pack 22. The battery 20 is, for example, a lithium-ion battery or the like, and is a secondary battery capable of charging and discharging. The battery 20 supplies power to the motor of the driving source.

[0012] The battery pack 22 is formed in a hollow box shape. The battery 20 is housed inside the battery pack 22. The battery pack 22 is formed of, for example, a metal material containing aluminum.

[0013] When the driver is using the vehicle 10, the battery 20 generates heat and its temperature rises. To suppress the temperature rise of the battery 20, the vehicle 10 has a configuration for cooling the battery 20. For example, air outside the vehicle 10 is introduced into the inside of the battery pack 22 in which the battery 20 is housed. The battery 20 is air-cooled by the air outside the vehicle 10 introduced into the inside of the battery pack 22.

[0014] Here, the water vapor in the air outside the vehicle 10 may contain chloride ions. For example, in a heavy snow area, a snow melting agent is used. The snow melting agent contains, for example, calcium chloride, sodium chloride, or the like. Therefore, in a place where the snow melting agent is used, there is a high possibility that the air contains more chloride ions than in a place where the snow melting agent is not used.

[0015] For example, the vehicle 10 traveling in a heavy snow area where the snow melting agent is used takes in the air containing a large amount of chloride ions outside the vehicle 10 into the inside of the battery pack 22 to air-cool the battery 20. Then, the chloride ions in the air taken into the inside of the battery pack 22 may cause corrosion of the battery pack 22. When the battery pack 22 is formed of a metal material containing aluminum, the corrosion of the battery pack 22 easily progresses due to chloride ions. When the battery pack 22 corrodes, the function of protecting the battery 20 by the battery pack 22 deteriorates.

[0016] Therefore, in the inspection system 1 of the present embodiment, the corrosion of the battery pack 22 that houses the battery 20 mounted on the vehicle 10 is inspected.

[0017] The vehicle 10 includes a chloride ion detection sensor 30, a first control device 32, a notification unit 34, and a vehicle-side interface 36.

[0018] The chloride ion detection sensor 30 is installed inside the battery pack 22. For example, the chloride ion detection sensor 30 is placed in a location inside the battery pack 22 where condensation is likely to occur. Any number of chloride ion detection sensors 30 can be installed inside the battery pack 22. The chloride ion detection sensor 30 is electrically connected to the first control device 32. The chloride ion detection sensor 30 is configured to detect chloride ions. The chloride ion detection sensor 30 will be described in detail later.

[0019] The first control device 32 comprises one or more first processors 40 and one or more first memories 42 connected to the first processors 40. The first memories 42 include ROM for storing programs and RAM as a work area. The first processors 40 cooperate with the programs contained in the first memories 42 to control various parts of the vehicle 10.

[0020] The first processor 40 also functions as a first inspection unit 44 by executing a program. The first inspection unit 44 inspects the battery pack 22 for corrosion based on the detected value of the chloride ion detection sensor 30. The first inspection unit 44 will be described in detail later.

[0021] The notification unit 34 is, for example, a warning indicator light located on the instrument panel. The notification unit 34 displays the inspection results from the first inspection unit 44. For example, if the notification unit 34 determines that there is a possibility of corrosion in the battery pack 22, it displays a message to that effect.

[0022] The vehicle-side interface 36 is electrically connected to the first control device 32. The vehicle-side interface 36 is configured to allow connectors for cables that connect devices to each other to be connected.

[0023] The external inspection device 12 is managed, for example, by a business or dealer that inspects and repairs vehicles 10. For the sake of explanation, the business that manages the external inspection device 12 may be referred to as the inspection business below. In the inspection system 1 of this embodiment, if a notification is issued that there is a possibility of corrosion in the battery pack 22 of vehicle 10, the driver of vehicle 10 brings the vehicle 10 to the inspection business. The inspection business then uses the external inspection device 12 to re-inspect the battery pack 22 of vehicle 10 for corrosion.

[0024] The external inspection device 12 includes an external inspection device side interface 50, a user interface 52, and a second control device 54.

[0025] The external inspection device side interface 50 is electrically connected to the second control device 54. The external inspection device side interface 50 is configured to allow connection of the connector of the cable that connects the devices to each other. Of the first and second terminals of the cable that connects the devices to each other, the first terminal is connected to the vehicle side interface 36, and the second terminal is connected to the external inspection device side interface 50. In this way, the first control device 32 of the vehicle 10 and the second control device 54 of the external inspection device 12 are electrically connected.

[0026] The user interface 52 includes an output device that presents various information to the user, such as a display device that shows various images or various types of information. The user interface 52 also includes an input device such as a touch panel that accepts user input.

[0027] The second control device 54 comprises one or more second processors 60 and one or more second memories 62 connected to the second processors 60. The second memories 62 include ROM in which programs and the like are stored, and RAM as a work area. The second processors 60 cooperate with the programs contained in the second memories 62 to control each part of the external inspection device 12.

[0028] The second processor 60 also functions as a second inspection unit 64 by executing a program. The second inspection unit 64 can acquire the detected value of the chloride ion detection sensor 30 through the first control device 32 when the first control device 32 and the second control device 54 are electrically connected. Based on the detected value of the chloride ion detection sensor 30, the second inspection unit 64 performs a corrosion inspection of the battery pack 22. The second inspection unit 64 will be described in detail later.

[0029] Figure 2 is a plan view illustrating the arrangement of the chloride ion detection sensor 30. Figure 3 is a first side perspective view illustrating the arrangement of the chloride ion detection sensor 30. Figure 4 is a second side perspective view illustrating the arrangement of the chloride ion detection sensor 30. Figure 3 shows a perspective view of the battery pack 22 from the bottom in Figure 2. Figure 4 shows a perspective view of the battery pack 22 from the right side in Figure 2.

[0030] In Figures 2 to 4, two batteries 20 are housed inside the battery pack 22. Each battery 20 is a battery module composed of multiple cells connected in series. Note that the number of batteries 20 housed inside the battery pack 22 is not limited to the two exemplified, but can be any number.

[0031] A battery control board 70 is placed on top of each battery 20. The battery control board 70 is fixed to the battery 20 by a board support 72 provided on top of the battery 20. The battery control board 70 performs functions such as detecting the temperature of the battery 20 and deriving the State of Charge (SOC) of the battery 20.

[0032] An arm 74 is provided on the upper side of the battery 20, extending to the side of the battery pack 22. The battery 20 is fixed to the battery pack 22 by the arm 74. The battery 20 is separated from the bottom 76 of the battery pack. However, the battery 20 is not limited to being fixed to the battery pack 22 by the arm 74. For example, the battery 20 may be provided with legs extending from its bottom surface toward the bottom 76 of the battery pack 22, and the battery 20 may be fixed to the battery pack 22 by these legs.

[0033] The vehicle 10 is equipped with an intake duct 80, an exhaust duct 82, and a fan 84. The intake duct 80 is formed in a tubular shape that connects the inside and outside of the battery pack 22. The intake duct 80 has an intake port 86 which is the end that opens to the outside of the battery pack 22, and an intake outlet end 88 which is the end that opens to the inside of the battery pack 22. The intake port 86 is located, for example, on the front side of the vehicle 10. The intake outlet end 88 is located, for example, near the side of the battery 20.

[0034] A portion of the outside air of the vehicle 10 enters the intake duct 80 through the intake port 86. The air that enters the intake duct 80 circulates through the intake duct 80 and is sent into the battery pack 22 from the intake outlet end 88. The battery 20 housed inside the battery pack 22 is air-cooled by the air that has been guided into the battery pack 22 through the intake duct 80.

[0035] The exhaust duct 82 is formed in a tubular shape that connects the inside and outside of the battery pack 22. The exhaust duct 82 has an exhaust port 90, which is the end that opens to the outside of the battery pack 22, and an exhaust inlet end 92, which is the end that opens to the inside of the battery pack 22. The exhaust port 90 is located, for example, on the rear side of the vehicle 10. The exhaust inlet end 92 is located, for example, near the side of the battery 20. More specifically, the exhaust inlet end 92 is located symmetrically with respect to the intake outlet end 88. For example, if the intake outlet end 88 is located on the battery pack 22 towards the front right of the vehicle 10, then the exhaust inlet end 92 is located on the battery pack 22 towards the rear left of the vehicle 10.

[0036] A portion of the air inside the battery pack 22 enters the exhaust duct 82 from the exhaust inlet end 92. The air that enters the exhaust duct 82 flows through the exhaust duct 82 and is sent out to the outside of the vehicle 10 from the exhaust port 90.

[0037] The fan 84 is installed, for example, in the middle of the intake duct 80. The fan 84 draws outside air from the vehicle 10 into the intake duct 80 through the intake port 86 and sends the drawn-in air into the battery pack 22. This promotes air cooling of the battery 20 by the outside air from the vehicle 10.

[0038] The fan 84 may be installed in the middle of the exhaust duct 82. In that case, the fan 84 draws air from inside the battery pack 22 into the exhaust duct 82, creating negative pressure inside the battery pack 22, and thus air from outside the vehicle 10 is drawn into the battery pack 22 through the intake duct 80. The fan 84 may also be omitted.

[0039] In situations where de-icing agents are used, the outside temperature is low, for example, below freezing. When vehicle 10 travels in such an environment, the cold air outside vehicle 10 is introduced into the battery pack 22 through the intake duct 80. On the other hand, the temperature of the air inside the battery pack 22 is relatively high, for example, 60°C, due to the heat generated by the battery 20. In other words, there is a large temperature difference between the air introduced from outside vehicle 10 into the battery pack 22 and the air inside the battery pack 22. As a result, condensation may occur in some of the air introduced from outside vehicle 10 into the battery pack 22.

[0040] For example, the intake outlet end 88 corresponds to the boundary where air introduced from outside the vehicle 10 into the battery pack 22 first comes into contact with the air inside the battery pack 22. Therefore, the intake outlet end 88 is the point where the temperature difference between the air introduced from outside the vehicle 10 into the battery pack 22 and the air inside the battery pack 22 is the largest. For this reason, the intake outlet end 88 is an example of a location where condensation is likely to occur.

[0041] Furthermore, since the exhaust port 90 of the exhaust duct 82 opens to the outside of the vehicle 10, the temperature of the exhaust port 90 is relatively low due to the ambient temperature. The exhaust inlet end 92 is connected to the exhaust port 90 by the exhaust duct 82, so the temperature of the exhaust inlet end 92 is also relatively low, similar to the exhaust port 90. For this reason, the exhaust inlet end 92 is a part where the temperature difference with the temperature of the air inside the battery pack 22 is relatively large. For this reason, the exhaust inlet end 92 is also an example of a location where condensation is likely to occur.

[0042] As described above, the chloride ion detection sensor 30 is positioned in a location where condensation is likely to occur. More specifically, the chloride ion detection sensor 30 is positioned near the intake outlet end 88 of the intake duct 80 and near the exhaust inlet end 92 of the exhaust duct 82. The vicinity of the intake outlet end 88 means a position within a predetermined range that includes the intake outlet end 88. For example, if the intake outlet end 88 of the intake duct 80 protrudes into the battery pack 22 from the connection point between the battery pack 22 and the intake duct 80, the vicinity of the intake outlet end 88 may be the part of the intake duct 80 that is inside the battery pack 22 from the connection point. The vicinity of the exhaust inlet end 92 means a position within a predetermined range that includes the exhaust inlet end 92. For example, if the exhaust inlet end 92 of the exhaust duct 82 protrudes into the battery pack 22 from the connection point between the battery pack 22 and the exhaust duct 82, the exhaust duct 82 on the side of the battery pack 22 that is closer to the exhaust inlet end 92 may be located.

[0043] The chloride ion detection sensor 30 is not limited to being provided in the vicinity of both the intake outlet end 88 and the exhaust inlet end 92. The chloride ion detection sensor 30 may be positioned at least one of the locations near the intake outlet end 88 and the exhaust inlet end 92.

[0044] Furthermore, the battery pack 22 has a water storage section 100 at its bottom 76. The water storage section 100 is configured such that at least a portion of the inner surface of the bottom 76 of the battery pack 22 is recessed toward the outside of the battery pack 22 compared to other parts of the inner surface of the bottom 76, and is capable of accumulating water produced by condensation.

[0045] The water reservoir 100 is located, for example, between the intake outlet end 88 and the exhaust inlet end 92. The water reservoir 100 is formed, for example, as a groove extending along the bottom 76 of the battery pack 22. The width and depth of the water reservoir 100 are roughly constant in the direction of its extension. The shape of the water reservoir 100 is not limited to the groove shape exemplified, but may be any shape. Furthermore, the inner surface of the bottom of the battery pack 22 may be a slope that gradually slopes downward vertically as it approaches the water reservoir 100.

[0046] The water generated by condensation naturally moves to the bottom 76 of the battery pack 22 due to gravity. The water that moves to the bottom 76 moves to the water storage section 100 via the slope of the bottom 76, and is stored and retained inside the water storage section 100.

[0047] The chloride ion detection sensors 30 are also positioned in the water storage section 100. For example, the chloride ion detection sensors 30 are dispersed in the direction of extension of the groove-shaped water storage section 100. By distributing multiple chloride ion detection sensors 30 in the water storage section 100, the accuracy of chloride ion detection can be improved.

[0048] In Figures 2 to 4, five chloride ion detection sensors 30 are arranged in the water storage section 100. However, the number of chloride ion detection sensors 30 at the water storage section 100 is not limited to this example and may be any number. Furthermore, if chloride ion detection sensors 30 are arranged at at least one of the intake outlet end 88 and the exhaust inlet end 92, the chloride ion detection sensors 30 at the water storage section 100 may be omitted.

[0049] Figure 5 is a circuit diagram illustrating the method for detecting chloride ions using the chloride ion detection sensor 30. For the sake of explanation, Figure 5 describes one of several chloride ion detection sensors 30 as a representative example. However, the explanation for other chloride ion detection sensors 30 is the same as that in Figure 5.

[0050] The chloride ion detection sensor 30 is a semiconductor sensor, such as an ISFET (Ion Selective Field Effect Transistor). The chloride ion detection sensor 30 has a first electrode 110, a second electrode 112, a control electrode 114, and a reference electrode 116.

[0051] The first electrode 110 corresponds to the drain of the ISFET, the second electrode 112 corresponds to the source of the ISFET, and the control electrode 114 corresponds to the gate of the ISFET. The reference electrode 116 is positioned with a predetermined gap 118 relative to the control electrode 114.

[0052] The first control device 32 is provided with a first power supply 120, a second power supply 122, and a current sensor 124. The first power supply 120 and the second power supply 122 are implemented, for example, by a voltage follower circuit or the like inside the first control device 32. The current sensor 124 is implemented, for example, by a current sense amplifier and an analog-to-digital converter inside the first control device 32.

[0053] The positive electrode of the first power supply 120 is connected to the first electrode 110 of the chloride ion detection sensor 30. The negative electrode of the first power supply 120 is connected to the second electrode 112 of the chloride ion detection sensor 30 via a current sensor 124. The first power supply 120 applies a first bias voltage Vds between the first electrode 110 and the second electrode 112 of the chloride ion detection sensor 30. The first bias voltage Vds corresponds to the drain-source voltage of the ISFET.

[0054] The current sensor 124 detects the output current Ids, which is the current between the first electrode 110 and the second electrode 112 of the chloride ion detection sensor 30. The output current Ids corresponds to the drain-source current of the ISFET.

[0055] The positive electrode of the second power supply 122 is connected to the reference electrode 116 of the chloride ion detection sensor 30. The negative electrode of the second power supply 122 is connected to the second electrode 112 of the chloride ion detection sensor 30. The second power supply 122 applies a second bias voltage Vgs between the reference electrode 116 and the second electrode 112 of the chloride ion detection sensor 30. The second bias voltage Vgs corresponds to the reference electrode-source voltage of the ISFET, in other words, the gate-source voltage.

[0056] As described above, there is a gap 118 between the reference electrode 116 and the control electrode 114. As a result, if there are no chloride ions in the gap 118, the control electrode 114 is insulated from the reference electrode 116. In other words, even if the second bias voltage Vgs is applied to the reference electrode 116, if there are no chloride ions in the gap 118, no voltage is applied to the control electrode 114, and no output current Ids flows.

[0057] Here, let's assume that water 130 is attached to the gap 118, spanning from the reference electrode 116 to the control electrode 114. This water 130 may be water vapor. Let's assume that this water 130 contains chloride ions. Then, chloride ions will be present in the gap 118.

[0058] In the chloride ion detection sensor 30, the potential of the control electrode 114 changes according to the voltage applied to the reference electrode 116 and the concentration of chloride ions present in the gap 118. For example, even if the voltage applied to the reference electrode 116 is constant, the potential of the control electrode 114 increases as the concentration of chloride ions present in the gap 118 increases. Also, in the chloride ion detection sensor 30, if chloride ions are present in the gap 118 at a constant concentration, the potential of the control electrode 114 increases as the voltage applied to the reference electrode 116 increases.

[0059] In the chloride ion detection sensor 30, the output current Ids between the first electrode 110 and the second electrode 112 changes in accordance with the change in the potential of the control electrode 114. For example, in the chloride ion detection sensor 30, the output current Ids between the first electrode 110 and the second electrode 112 increases as the potential of the control electrode 114 increases.

[0060] Based on these conditions, the chloride ion detection sensor 30 outputs an output current Ids according to the concentration of chloride ions present in the gap 118. This output current Ids corresponds to the detected value of the chloride ion detection sensor 30. The first control device 32 can obtain the chloride ion detection result from the chloride ion detection sensor 30 by measuring the output current Ids of the chloride ion detection sensor 30 with the current sensor 124.

[0061] Based on these factors, if the output current Ids exceeds a predetermined threshold, it can be assumed that the chloride ion concentration in the gap 118 is high. A high chloride ion concentration suggests a high probability of corrosion in the battery pack 22. The predetermined threshold is set to an appropriate value that can distinguish a high probability of corrosion in the battery pack 22. This predetermined threshold is determined in advance through experiments or other means.

[0062] Figure 6 illustrates the characteristics of the chloride ion detection sensor 30. In Figure 6, the horizontal axis represents the second bias voltage Vgs, and the vertical axis represents the output current Ids. Figure 6 shows an example where a relatively high concentration of chloride ions is present in the gap 118.

[0063] As shown in Figure 6, when a high concentration of chloride ions is present in gap 118, the output current Ids with respect to the second bias voltage Vgs exhibits a so-called hysteresis response.

[0064] For example, suppose the output current Ids is measured while increasing the second bias voltage Vgs from the minimum voltage Vgsmin within a predetermined range to the maximum voltage Vgsmax within the same predetermined range. In this case, the output current Ids changes along the path indicated by the upward arrow 140 in Figure 6. Note that the minimum voltage Vgsmin can be, for example, 1V, and the maximum voltage Vgsmax can be, for example, 5V, but these can be any values.

[0065] On the other hand, suppose we measure the output current Ids while decreasing the second bias voltage Vgs from the maximum voltage Vgsmax to the minimum voltage Vgsmin. In this case, the output current Ids changes along the path indicated by the downward arrow 142 in Figure 6.

[0066] Here, the output current Ids corresponding to the minimum voltage Vgsmin is defined as the minimum current Idsmin. The output current Ids corresponding to the maximum voltage Vgsmax is defined as the maximum current Idsmax. The output current Ids midway between the maximum current Idsmax and the minimum current Idsmin is defined as the intermediate current Id s Let's call it mid.

[0067] Intermediate current Id when the second bias voltage Vgs is increased s The second bias voltage Vgs corresponding to mid is the rising voltage Vgsu. On the other hand, the intermediate current Id when the second bias voltage Vgs is decreased. s The second bias voltage Vgs, corresponding to mid, is the falling voltage Vgsd. The falling voltage Vgsd is lower than the rising voltage Vgsu. That is, as shown by the double arrow 150 in Figure 6, the intermediate current Id s The second bias voltage Vgs, corresponding to mid, has a voltage range equal to the difference between the rising voltage Vgsu and the falling voltage Vgsd.

[0068] This voltage range increases as the concentration of chloride ions present in gap 118 increases.

[0069] Based on these considerations, by determining whether the voltage range exceeds a predetermined voltage range, it is possible to determine whether the change in output current Ids in response to a change in the second bias voltage Vgs exhibits a hysteresis response. If a hysteresis response is determined, it corresponds to a relatively high concentration of chloride ions present in the gap 118, and therefore, it can be estimated that there is a high probability of corrosion of the battery pack 22. The predetermined voltage range is set to an appropriate value that can distinguish a high probability of corrosion of the battery pack 22. This predetermined voltage range is determined in advance through experiments or other means.

[0070] Figure 7 is a flowchart illustrating the operation flow of the first inspection unit 44 in the vehicle 10. The first inspection unit 44 starts the series of processes shown in Figure 7, for example, when a predetermined time has elapsed since the vehicle 10 was started. The predetermined time is set, for example, to the time it takes for the temperature of the battery 20 to become sufficiently high. Alternatively, the first inspection unit 44 may start the series of processes shown in Figure 7 when the temperature of the battery 20 reaches or exceeds a predetermined temperature after the vehicle 10 has been started. Furthermore, the first inspection unit 44 may repeat the series of processes shown in Figure 7 at a predetermined cycle.

[0071] First, the first inspection unit 44 applies a predetermined first bias voltage Vds to the first electrode 110 (S10). Next, the first inspection unit 44 applies a predetermined second bias voltage Vgs to the reference electrode 116 (S11). The first bias voltage Vds and the second bias voltage Vgs may be the same value or different values.

[0072] The first inspection unit 44 acquires the output current Ids using the current sensor 124 while the first bias voltage Vds and the second bias voltage Vgs are applied (S12). The first inspection unit 44 then determines whether the acquired output current Ids is below a predetermined threshold (S13).

[0073] If the output current Ids is below a predetermined threshold (YES in S13), the first inspection unit 44 terminates the series of processes. In this case, since there are not many chloride ions in the gap 118 of the chloride ion detection sensor 30, which is located in a position where condensation is likely to occur, it is assumed that there are not many chloride ions in the battery pack 22 as a whole. In other words, in this case, it is assumed that there is little possibility that the battery pack 22 is corroded.

[0074] If the output current Ids is greater than a predetermined threshold (NO in S13), the first inspection unit 44 determines that there is a possibility of corrosion in the battery pack 22 (S14). The first inspection unit 44 then has the notification unit 34 notify that there is a possibility of corrosion in the battery pack 22 (S15), and terminates the series of processes. In this case, since there are many chloride ions in the gap 118 of the chloride ion detection sensor 30 which is located in a position where condensation is likely to occur, it is assumed that there are also many chloride ions in the entire battery pack 22. If there are many chloride ions in the entire battery pack 22, it is assumed that there is a high possibility that the battery pack 22 is corroded, and therefore the notification is made accordingly.

[0075] When the driver of vehicle 10 becomes aware of a notification indicating potential corrosion of the battery pack 22, they transport vehicle 10 to an inspection company and request a detailed inspection from the inspection company.

[0076] Figure 8 is a flowchart illustrating the inspection process at the inspection company. The inspection company connects the vehicle-side interface 36 of the vehicle 10, which has been notified of the potential corrosion of the battery pack 22, to the external inspection device-side interface 50 of the external inspection device 12 with a cable. This allows the external inspection device 12 to control the first control device 32 of the vehicle 10 and acquire the detection results of the chloride ion detection sensor 30 of the vehicle 10. Subsequently, the series of processes shown in Figure 8 are carried out.

[0077] First, the inspection operator operates the external inspection device 12 to cause the second inspection unit 64 to perform a hysteresis confirmation process (S20). The hysteresis confirmation process is a process to confirm whether the change in output current Ids in response to the change in the second bias voltage Vgs is a hysteresis response. The flow of the hysteresis confirmation process will be described in detail later. Hereafter, the hysteresis confirmation process performed after a notification indicating the possibility of corrosion of the battery pack 22 is issued, as in step S20, may be referred to as the first hysteresis confirmation process.

[0078] The second inspection unit 64 determines whether or not a hysteresis response was determined in the first hysteresis confirmation process, that is, in the hysteresis confirmation process of step S20 (S21).

[0079] If a hysteresis response is not detected (NO in S21), the second inspection unit 64 determines that there is no corrosion in the battery pack 22 (S22), and the inspection by the external inspection device 12 is completed. In this case, although the vehicle 10's notification unit 34 has issued a notification, it is considered that there is actually no corrosion in the battery pack 22. The second inspection unit 64 may also clear the notification from the vehicle 10's notification unit 34.

[0080] If a hysteresis response is detected (YES in S21), it is presumed that there is a possibility of corrosion in the battery pack 22. However, in this case, in order to improve the measurement accuracy of the chloride ion detection sensor 30, the second inspection unit 64 instructs the inspection company to clean the chloride ion detection sensor 30 (S23).

[0081] When the inspection company recognizes the instruction to clean, it cleans the chloride ion detection sensor 30. For example, the inspection company prepares a cleaning device having a cleaning nozzle capable of dispensing a cleaning agent such as water, a suction port capable of sucking up the cleaning agent, and a drying nozzle that discharges dry air. The inspection company inserts the cleaning nozzle of the cleaning device into the battery pack 22 through the intake port 86 of the intake duct 80 or the exhaust port 90 of the exhaust duct 82. The inspection company then operates the cleaning device to discharge the cleaning agent from the nozzle and cleans the chloride ion detection sensor 30 with the cleaning agent. The inspection company operates the cleaning device to suck up the cleaning agent discharged into the battery pack 22 through the suction port. The inspection company operates the cleaning device to discharge dry air from the drying nozzle and dry the chloride ion detection sensor 30. Note that the specific method for cleaning the chloride ion detection sensor 30 is not limited to the example given, and any method can be adopted. For example, the chloride ion detection sensor 30 may be detachably installed on the intake duct 80, exhaust duct 82, or battery pack 22. The inspection operator may then remove the chloride ion detection sensor 30 from the vehicle 10, clean the chloride ion detection sensor 30, and then reinstall the chloride ion detection sensor 30 in its original position.

[0082] In this case, if the battery pack 22 is corroded, it is highly likely that the inside of the battery pack 22 is filled with chloride ions. Therefore, in situations where the battery pack 22 is corroded, even if the chloride ion detection sensor 30 is cleaned, chloride ions will reattach to the chloride ion detection sensor 30 due to the chloride ions that have accumulated inside the battery pack 22.

[0083] Therefore, after the cleaning of the chloride ion detection sensor 30 by the inspection company is completed, the inspection company operates the external inspection device 12 to have the second inspection unit 64 perform the hysteresis confirmation process again (S24). The hysteresis confirmation process in step S24 is the same as the hysteresis confirmation process in step S20. Hereafter, the hysteresis confirmation process after cleaning the chloride ion detection sensor 30, as in step S24, may be referred to as the second hysteresis confirmation process.

[0084] The second inspection unit 64 determines whether or not a hysteresis response was determined in the second hysteresis confirmation process, that is, in the hysteresis confirmation process of step S24 (S25).

[0085] If the chloride ion detection sensor 30 is determined to exhibit a hysteresis response even after cleaning (YES in S25), it is highly likely that the inside of the battery pack 22 is filled with chloride ions. For this reason, the second inspection unit 64 determines that the battery pack 22 is corroded (S26). Upon recognizing the determination that the battery pack 22 is corroded, the inspection operator replaces the battery pack 22 (S27) and terminates the inspection.

[0086] If the hysteresis confirmation process after cleaning the chloride ion detection sensor 30 determines that there is no hysteresis response (NO in S25), it is assumed that there are not enough chloride ions inside the battery pack 22 to cause corrosion of the battery pack 22. Therefore, the second inspection unit 64 determines that there is no corrosion of the battery pack 22 (S28).

[0087] However, since the first hysteresis confirmation process before cleaning initially determined that a hysteresis response occurred, it is assumed that the battery pack 22 is in a state where it is prone to corrosion. Therefore, the second inspection unit 64 changes the maintenance settings in the first control device 32 to strengthen maintenance related to the corrosion of the battery pack 22 (S29), and then terminates the inspection.

[0088] With the maintenance settings changed, the first inspection unit 44 of the vehicle 10 will now perform inspections of the battery pack 22 for corrosion using the chloride ion detection sensor 30, as well as other processes in addition to the inspection using the chloride ion detection sensor 30.

[0089] For example, the first inspection unit 44 adds a process to acquire the ambient temperature sequentially and determine whether the ambient temperature has remained below a predetermined temperature for a predetermined period of time or longer. If the first inspection unit 44 determines that the ambient temperature has remained below a predetermined temperature for a predetermined period of time or longer, it determines that the battery pack 22 is in a condition where corrosion is likely to progress. If it makes such a determination, the first inspection unit 44 starts the series of processes shown in Figure 7, even if the timing for executing the series of processes shown in Figure 7 has not yet arrived. This makes it possible to detect the possibility of corrosion of the battery pack 22 at an early stage. Note that the specific contents of the enhanced maintenance are not limited to the examples given and can be any contents.

[0090] Figure 9 illustrates the flow of the hysteresis verification process. The series of processes shown in Figure 9 are performed in both the first hysteresis verification process in step S20 and the second hysteresis verification process in step S24.

[0091] When the hysteresis confirmation process is started, the second inspection unit 64 applies the first bias voltage Vds to the first electrode 110 (S40).

[0092] Next, the second inspection unit 64 determines the second bias voltage Vgs (S41). Here, the order in which the second bias voltage Vgs is determined is predetermined, such that it is increased by predetermined voltages from the minimum voltage Vgsmin to the maximum voltage Vgsmax, and then decreased by predetermined voltages from the maximum voltage Vgsmax to the minimum voltage Vgsmin. The second inspection unit 64 determines the current second bias voltage Vgs according to this determination order.

[0093] The second inspection unit 64 applies the determined second bias voltage Vgs to the reference electrode 116 (S42). The second inspection unit 64 then acquires the output current Ids at that time using the current sensor 124 (S43). The second inspection unit 64 associates the applied second bias voltage Vgs with the acquired output current Ids and stores it in the second memory 62 (S44).

[0094] Next, the second inspection unit 64 determines whether the measurement termination condition has been met (S45). For example, in step S41, the second inspection unit 64 determines that the measurement termination condition has been met if all determinations of the second bias voltage Vgs according to a predetermined determination order have been completed.

[0095] If it is determined that the measurement termination condition is not met (NO in S45), the second inspection unit 64 returns to the process in step S41 and determines the next second bias voltage Vgs in a predetermined determination order (S41).

[0096] In other words, the second inspection unit 64 repeatedly applies the second bias voltage Vgs while changing it, and acquires the output current Ids each time the second bias voltage Vgs is changed.

[0097] If the measurement termination condition is determined to be met (S45), the second inspection unit 64 derives the voltage range based on the measurement results (S46). For example, the second inspection unit 64 derives the difference value by subtracting the output current Ids at the minimum voltage Vgsmin (i.e., minimum current Idsmin) from the output current Ids at the maximum voltage Vgsmax (i.e., maximum current Idsmax). The second inspection unit 64 divides this difference value by 2 to obtain the intermediate current Id s The mid is derived. The second inspection unit 64 refers to the measurement results stored in the second memory 62 and determines the intermediate current Id s The rising voltage Vgsu and falling voltage Vgsd corresponding to mid are obtained. The second inspection unit 64 derives the voltage width by subtracting the falling voltage Vgsd from the rising voltage Vgsu.

[0098] Next, the second inspection unit 64 determines whether the derived voltage width is greater than or equal to a predetermined voltage width (S47).

[0099] If the derived voltage width is greater than or equal to a predetermined voltage width (YES in S47), the second inspection unit 64 determines that the change in output current Ids in response to the change in the second bias voltage Vgs is a hysteresis response (S48), and terminates the hysteresis confirmation process.

[0100] If the derived voltage range is less than a predetermined voltage range (NO in S47), the second inspection unit 64 determines that the change in output current Ids in response to the change in the second bias voltage Vgs does not result in a hysteresis response (S49), and terminates the hysteresis confirmation process.

[0101] Then, as explained in Figure 8, the second inspection unit 64 determines corrosion of the battery pack 22 based on the result of the hysteresis confirmation process.

[0102] As described above, in the inspection system 1 of this embodiment, in a configuration in which the battery 20 of the vehicle 10 is air-cooled, a chloride ion detection sensor 30 is placed inside the battery pack 22. As a result, in the inspection system 1 of this embodiment, chloride ions in the air introduced into the battery pack 22 to air-cool the battery 20 can be detected by the chloride ion detection sensor 30. Then, in the inspection system 1 of this embodiment, corrosion of the battery pack 22 is inspected based on the detected value of the chloride ion detection sensor 30. As a result, in the inspection system 1 of this embodiment, corrosion of the battery pack 22 can be easily detected without replacing the battery pack 22.

[0103] As shown in Figure 8, the inspection by the inspection company involved two hysteresis confirmation processes. Performing the hysteresis confirmation process twice allows for more accurate detection of corrosion in the battery pack 22. However, the method is not limited to performing the hysteresis confirmation process twice; it may also be performed only once.

[0104] Figure 10 is a flowchart showing an example where the hysteresis confirmation process is performed only once. Figure 10 corresponds to the flowchart in Figure 8, but with the second hysteresis confirmation process omitted. As shown in Figure 10, if the hysteresis confirmation process determines that a hysteresis response has occurred (YES in S21), the second inspection unit 64 determines that there is corrosion in the battery pack 22 (S60). Upon recognizing the determination that there is corrosion in the battery pack 22, the inspection operator replaces the battery pack 22 (S61) and terminates the inspection.

[0105] In the configuration where the hysteresis confirmation process is performed only once, corrosion of the battery pack 22 can be detected with greater accuracy compared to the configuration where inspection by the external inspection device 12 is not performed.

[0106] Furthermore, as described above, the first inspection unit 44 determines that there is a possibility of corrosion in the battery pack 22 if the output current Ids exceeds a predetermined threshold. If the first inspection unit 44 determines that there is a possibility of corrosion in the battery pack 22, the second inspection unit 64 performs a hysteresis confirmation process and determines whether the battery pack 22 is corroded based on the result of the hysteresis confirmation process. However, the inspection by the second inspection unit 64 may be omitted, and at least the inspection by the first inspection unit 44 may be performed. In this case, the first inspection unit 44 may clearly determine whether or not there is corrosion in the battery pack 22 based on whether the output current Ids exceeds a threshold.

[0107] Figure 11 is a flowchart showing an example of a case where only the inspection by the first inspection unit 44 is performed. As shown in Figure 11, if the output current Ids is below a predetermined threshold (YES in S13), the first inspection unit 44 determines that there is no corrosion in the battery pack 22 (S70).

[0108] If the output current Ids exceeds a predetermined threshold (NO in S13), the first inspection unit 44 determines that there is corrosion in the battery pack 22 (S71). The first inspection unit 44 then causes the notification unit 34 to notify that there is corrosion in the battery pack 22 (S15).

[0109] In this example, corrosion of the battery pack 22 can be detected without performing inspections using the external inspection device 12, thereby reducing the burden of inspections on the inspection company.

[0110] Embodiments of the present invention have been described above with reference to the attached drawings, but it goes without saying that the present invention is not limited to these embodiments. It is clear to those skilled in the art that various modifications or alterations can be conceived within the scope of the claims, and these will naturally also fall within the technical scope of the present invention.

[0111] For example, in the above embodiment, the second control device 54 was provided in the external inspection device 12. However, the second control device 54 may be provided in the vehicle 10. That is, in the vehicle 10, the second inspection unit 64 may perform an inspection including hysteresis confirmation processing. [Explanation of Symbols]

[0112] 1. Inspection System 10 vehicles 20 batteries 22 Battery Packs 30 Chloride ion detection sensor 32 First Control Device 40 First Processor 42 First Memory 54 Second control device 60 Second Processor 62 Second Memory 76 Bottom 80 Intake duct 82 Exhaust duct 88 Intake outlet side end 92 Exhaust inlet side end 100 Water storage section 110 1st electrode 112 2nd electrode 114 Control electrodes 116 Reference electrode 118 Gap Vgs Second bias voltage Ids Output Current

Claims

1. A battery pack, which houses the battery installed in the vehicle and is made of metal material, An intake duct capable of drawing outside air from the vehicle into the battery pack to air-cool the battery, An exhaust duct that guides the air inside the battery pack to the outside of the vehicle, One or more chloride ion detection sensors, which are disposed inside the battery pack and capable of detecting chloride ions, First control device, Equipped with, The first control device is One or more first processors, One or more first memories connected to the first processor, It has, The first processor is, Based on the detected value of the chloride ion detection sensor, the battery pack is inspected for corrosion. An inspection system that performs processing including the following.

2. The inspection system according to claim 1, wherein at least one of the chloride ion detection sensors is located near the end of the intake duct that opens into the battery pack, and near the end of the exhaust duct that opens into the battery pack.

3. The aforementioned battery pack is At least a portion of the inner surface of the bottom of the battery pack has a water-retaining section that is recessed toward the outside of the battery pack, The inspection system according to claim 1, wherein at least one of the chloride ion detection sensors is located at the position of the water containment section.

4. The chloride ion detection sensor is, A semiconductor sensor comprising a first electrode, a second electrode, a control electrode, and a reference electrode positioned with a predetermined gap relative to the control electrode, wherein the potential of the control electrode changes according to the voltage applied to the reference electrode and the concentration of chloride ions present in the predetermined gap, and the current between the first electrode and the second electrode changes according to the potential of the control electrode. The current between the first electrode and the second electrode when a voltage is applied to the reference electrode is detected as a detected value. The first processor is, If the detected value of the chloride ion detection sensor exceeds a predetermined threshold, it is determined that there is a possibility of corrosion in the battery pack. The inspection system according to claim 1, which performs a process including the following:

5. Equipped with a second control device, The second control device is One or more second processors, One or more second memories connected to the second processor, It has, The second processor is, If the first processor determines that there is a possibility of corrosion of the battery pack, a hysteresis confirmation process is performed to change the voltage applied to the reference electrode and to determine whether the change in current between the first electrode and the second electrode in response to the change in the voltage applied to the reference electrode is a hysteresis response. Based on the result of the hysteresis confirmation process, the corrosion of the battery pack is determined, The inspection system according to claim 4, which performs a process including the following:

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