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 battery packs for corrosion. [Background technology]

[0002] For example, Patent Document 1 discloses a fuel cell system that uses a liquid refrigerant to cool the fuel cell. In such a fuel cell system, impurity ions are detected that are eluted from metal piping that serves as a refrigerant flow path into ion-exchanged water, which is the refrigerant. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-127550 Summary of the Invention [Problem to be solved by the invention]

[0004] Some vehicles are configured to cool the battery using air outside the vehicle. For example, when such a vehicle is driven in a heavy snow region where snow-melting agents are used, air containing a large amount of chloride ions from outside the vehicle is drawn into the battery pack to cool the battery. This can cause corrosion of the battery pack due to the chloride ions in the air drawn into the battery pack. This corrosion reduces the battery pack's ability to protect the battery.

[0005] SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an inspection system that can easily detect corrosion in a battery pack. [Means for solving the problem]

[0006] In order to solve the above problem, an inspection system according to one embodiment of the present invention comprises: a battery pack that houses a battery to be mounted on the vehicle; an intake duct that can guide air outside the vehicle into the battery pack to air-cool the battery; an exhaust duct that guides air inside the battery pack to the outside of the vehicle; one or more chloride ion detection sensors disposed inside the battery pack and capable of detecting chloride ions; a first control device; Equipped with The first control device is one or more first processors; one or more first memories coupled to the first processor; and The first processor inspecting the battery pack for corrosion based on the detected value of the chloride ion detection sensor; Execute the process including. [Effects of the Invention]

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

[0008] [Figure 1] FIG. 1 is a schematic block diagram showing the configuration of an inspection system according to this embodiment. [Figure 2] FIG. 2 is a plan view illustrating the arrangement of the chloride ion detection sensor. [Figure 3] FIG. 3 is a first side perspective view illustrating the arrangement of the chloride ion detection sensor. [Figure 4] FIG. 4 is a second side perspective view illustrating the arrangement of the chloride ion detection sensor. [Figure 5] FIG. 5 is a circuit diagram illustrating a method for detecting chloride ions using a chloride ion detection sensor. [Figure 6] FIG. 6 is a diagram illustrating the characteristics of the chloride ion detection sensor. [Figure 7] FIG. 7 is a flowchart illustrating the flow of operations of the first inspection unit in the vehicle. [Figure 8] FIG. 8 is a flowchart illustrating the flow of an inspection at an inspection company. [Figure 9] FIG. 9 is a diagram illustrating 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 of a case where only the inspection by the first inspection unit is performed. DETAILED DESCRIPTION OF THE INVENTION

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

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

[0011] Vehicle 10 is, for example, an electric vehicle or a hybrid electric vehicle, and includes a motor as a drive source for traveling. Vehicle 10 is equipped with a battery 20 and a battery pack 22. Battery 20 is, for example, a lithium-ion battery, which is a secondary battery that can be charged and discharged. Battery 20 supplies power to the motor that is the drive source.

[0012] The battery pack 22 is formed in the shape of a hollow box. The battery 20 is housed inside the battery pack 22. The battery pack 22 is made of a metal material including, for example, 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 battery pack 22 that houses the battery 20. The battery 20 is air-cooled by the air outside the vehicle 10 that is introduced into the battery pack 22.

[0014] Here, water vapor in the air outside the vehicle 10 may contain chloride ions. For example, in areas with heavy snowfall, snow-melting agents are used to melt snow. Snow-melting agents include, for example, calcium chloride and sodium chloride. Therefore, in places where snow-melting agents are used, there is a high possibility that the air contains more chloride ions than in places where snow-melting agents are not used.

[0015] For example, a vehicle 10 traveling in a heavy snow region where snow-melting agents are used will take air containing a large amount of chloride ions from outside the vehicle 10 into the battery pack 22 to air-cool the battery 20. In this case, the chloride ions in the air taken into the battery pack 22 may cause corrosion of the battery pack 22. If the battery pack 22 is made of a metal material containing aluminum, the chloride ions are likely to cause corrosion of the battery pack 22. If the battery pack 22 corrodes, the function of the battery pack 22 to protect the battery 20 will be reduced.

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

[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 provided inside the battery pack 22. For example, the chloride ion detection sensor 30 is disposed at a position inside the battery pack 22 where condensation is likely to occur. Any number of chloride ion detection sensors 30 may be provided inside the battery pack 22. The chloride ion detection sensors 30 are electrically connected to the first control device 32. The chloride ion detection sensors 30 are configured to be able to detect chloride ions. The chloride ion detection sensors 30 will be described in detail later.

[0019] The first control device 32 includes one or more first processors 40 and one or more first memories 42 connected to the first processors 40. The first memories 42 include a ROM in which programs and the like are stored and a RAM as a work area. The first processor 40 cooperates with the programs stored in the first memory 42 to control each part of the vehicle 10.

[0020] The first processor 40 executes a program to function as a first inspection unit 44. The first inspection unit 44 inspects the battery pack 22 for corrosion based on the detection 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 disposed on an instrument panel. The notification unit 34 displays the inspection result by the first inspection unit 44. For example, if it is determined that there is a possibility of corrosion in the battery pack 22, the notification unit 34 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 be able to connect connectors of cables that connect devices together.

[0023] The external inspection device 12 is managed, for example, by a business or dealer that inspects and repairs the vehicle 10. For ease of explanation, the business that manages the external inspection device 12 may be referred to as an inspection business. In the inspection system 1 of this embodiment, when a notification is issued in the vehicle 10 that there is a possibility of corrosion in the battery pack 22, the driver of the vehicle 10 brings the vehicle 10 into an inspection business. The inspection business then uses the external inspection device 12 to re-inspect the battery pack 22 of the 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 be able to connect a connector of a cable that connects devices together. Of the first and second terminals of the cable that connects devices together, 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. This electrically connects the first control device 32 of the vehicle 10 and the second control device 54 of the external inspection device 12.

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

[0027] The second control device 54 includes one or more second processors 60 and one or more second memories 62 connected to the second processors 60. The second memory 62 includes a ROM in which programs and the like are stored and a RAM as a work area. The second processor 60 cooperates with the programs stored in the second memory 62 to control each section of the external inspection device 12.

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

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

[0030] 2 to 4, two batteries 20 are housed inside the battery pack 22. One battery 20 is a battery module configured by connecting a plurality of cells in series. Note that the number of batteries 20 housed inside the battery pack 22 is not limited to two as illustrated, and may be any number.

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

[0032] An arm 74 extending to the side of the battery pack 22 is provided on the upper part of the side of the battery 20. The battery 20 is fixed to the battery pack 22 by the arm 74. The battery 20 is spaced apart from a bottom 76 of the battery pack. Note that the embodiment is not limited to the embodiment in which the battery 20 is fixed to the battery pack 22 by the arm 74. For example, the battery 20 may be provided with legs extending from the bottom surface of the battery 20 toward the bottom 76 of the battery pack 22, and the battery 20 may be fixed to the battery pack 22 by the legs.

[0033] The vehicle 10 includes 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 an end that opens to the outside of the battery pack 22, and an intake outlet side end 88, which is an 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 side end 88 is located, for example, near the side of the battery 20.

[0034] A portion of the air outside the vehicle 10 enters the inside of the intake duct 80 through the intake port 86. The air that has entered the inside of the intake duct 80 flows through the intake duct 80 and is sent out from the intake outlet side end 88 into the inside of the battery pack 22. The battery 20 housed inside the battery pack 22 is air-cooled by the air that has been guided into the inside of 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 an end that opens to the outside of the battery pack 22, and an exhaust inlet side end 92, which is an 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 side end 92 is located, for example, near a side surface of the battery 20. More specifically, the exhaust inlet side end 92 is located symmetrically with respect to the intake outlet side end 88. For example, if the intake outlet side end 88 is located closer to the front right of the battery pack 22 than the vehicle 10, the exhaust inlet side end 92 is located closer to the rear left of the battery pack 22 than the vehicle 10.

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

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

[0038] The fan 84 may be provided midway through the exhaust duct 82. In this case, the fan 84 draws the air inside the battery pack 22 into the exhaust duct 82, creating a negative pressure inside the battery pack 22, and therefore air 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 a situation where a de-icing agent is used, the outside air temperature is low, for example, below freezing. When the vehicle 10 is traveling in such an environment, low-temperature air outside the vehicle 10 is introduced into the battery pack 22 through the intake duct 80. Meanwhile, the temperature of the air inside the battery pack 22 is relatively high, for example, at 60°C, due to heat generated by the battery 20. In other words, there is a large temperature difference between the temperature of the air introduced into the battery pack 22 from outside the vehicle 10 and the temperature of the air inside the battery pack 22. This can cause condensation to form on some of the air introduced into the battery pack 22 from outside the vehicle 10.

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

[0041] Furthermore, because 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 outside air temperature. Because the exhaust inlet side end 92 is connected to the exhaust port 90 by the exhaust duct 82, the temperature of the exhaust inlet side end 92 is relatively low, just like the exhaust port 90. For this reason, the temperature difference between the exhaust inlet side end 92 and the temperature of the air inside the battery pack 22 is relatively large. For this reason, the exhaust inlet side 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 disposed in a position where condensation is likely to occur. More specifically, the chloride ion detection sensor 30 is disposed near the intake outlet end 88 of the intake duct 80 and near the exhaust inlet end 92 of the exhaust duct 82. "Near the intake outlet end 88" means a position within a predetermined range including the intake outlet end 88. For example, if the intake outlet end 88 of the intake duct 80 protrudes into the inside of the battery pack 22 from a connection between the intake duct 80 and the battery pack 22, the intake duct 80 that is closer to the inside of the battery pack 22 than the connection may be considered to be near the intake outlet end 88. "Near the exhaust inlet end 92" means a position within a predetermined range including the exhaust inlet end 92. For example, if the exhaust inlet side end 92 of the exhaust duct 82 protrudes into the inside of the battery pack 22 from the connection part between the battery pack 22 and the exhaust duct 82, the exhaust duct 82 that is closer to the inside of the battery pack 22 than the connection part of the exhaust duct 82 may be located near the exhaust inlet side end 92.

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

[0044] The battery pack 22 also has a water storage section 100 in 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 positions on the inner surface of the bottom 76, and is capable of storing water generated by condensation.

[0045] The water containing section 100 is located, for example, between the intake outlet end 88 and the exhaust inlet end 92. The water containing section 100 is formed, for example, in the shape of a groove extending along the bottom 76 of the battery pack 22. The width and depth of the water containing section 100 are approximately constant in the direction in which the water containing section 100 extends. The shape of the water containing section 100 is not limited to the groove shape shown as an example, and may be any shape. Furthermore, the inner surface of the bottom of the battery pack 22 may be sloped so that it gradually slopes vertically downward as it approaches the water containing section 100.

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

[0047] The chloride ion detection sensors 30 are also arranged at the position of the water storage section 100. For example, the chloride ion detection sensors 30 are arranged dispersedly in the extension direction of the groove-shaped water storage section 100. By distributing a plurality of chloride ion detection sensors 30 in the water storage section 100, the detection accuracy of chloride ions can be improved.

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

[0049] Fig. 5 is a circuit diagram illustrating a method for detecting chloride ions using the chloride ion detection sensor 30. For ease of explanation, Fig. 5 will explain one arbitrary chloride ion detection sensor 30 as a representative of the multiple chloride ion detection sensors 30. However, the explanation of Fig. 5 also applies to the other chloride ion detection sensors 30.

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

[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 disposed with a predetermined gap 118 from 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 realized, for example, by a voltage follower circuit or the like inside the first control device 32. The current sensor 124 is realized, for example, by a current sense amplifier, an analog-to-digital converter, or the like 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 an output current Ids, which is a 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. That is, 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 us assume that water 130 is attached across the gap 118, from the reference electrode 116 to the control electrode 114. This water 130 may be water vapor. Let us assume that this water 130 contains chloride ions. In this case, 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 higher the concentration of chloride ions present in the gap 118, the higher the potential of the control electrode 114. Furthermore, in the chloride ion detection sensor 30, when chloride ions are present in the gap 118 at a constant concentration, the higher the voltage applied to the reference electrode 116, the higher the potential of the control electrode 114.

[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, as the potential of the control electrode 114 increases, the output current Ids between the first electrode 110 and the second electrode 112 increases.

[0060] As a result, 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 detection value of the chloride ion detection sensor 30. The first control device 32 can obtain the detection result of chloride ions by 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] In light of these, when the output current Ids exceeds a predetermined threshold, it can be considered that the concentration of chloride ions in the gap 118 is high. A high concentration of chloride ions can be estimated to indicate a high possibility of corrosion of the battery pack 22. The predetermined threshold is set to an appropriate value that can distinguish a high possibility of corrosion of the battery pack 22. This predetermined threshold is determined in advance through experiments or the like.

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

[0063] As shown in FIG. 6, when a high concentration of chloride ions is present in the 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 the second bias voltage Vgs is increased from a minimum voltage Vgsmin within a predetermined range to a maximum voltage Vgsmax within the predetermined range. In this case, the output current Ids changes along the path indicated by the upward arrow 140 in FIG. 6. Note that the minimum voltage Vgsmin may be, for example, 1 V, and the maximum voltage Vgsmax may be, for example, 5 V, but these may also be any other values.

[0065] On the other hand, suppose that the output current Ids is measured while the second bias voltage Vgs is decreased 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 FIG.

[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 intermediate between the maximum current Idsmax and the minimum current Idsmin is defined as the intermediate current Idxmid.

[0067] The second bias voltage Vgs corresponding to the intermediate current Idxmid when the second bias voltage Vgs is increased is the rising voltage Vgsu. On the other hand, the second bias voltage Vgs corresponding to the intermediate current Idxmid when the second bias voltage Vgs is decreased is the falling voltage Vgsd. The falling voltage Vgsd is lower than the rising voltage Vgsu. In other words, as indicated by the double-headed arrow 150 in FIG. 6, the second bias voltage Vgs corresponding to the intermediate current Idxmid has a voltage range equal to the rising voltage Vgsu minus the falling voltage Vgsd.

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

[0069] In light of these, by determining whether the voltage width is equal to or greater than a predetermined voltage width, it is possible to determine whether the change in the output current Ids in response to a change in the second bias voltage Vgs is a hysteretic response. If it is determined that a hysteretic response has occurred, this 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 possibility of corrosion of the battery pack 22. The predetermined voltage width is set to an appropriate value that can distinguish a high possibility of corrosion of the battery pack 22. This predetermined voltage width is determined in advance through experiments or the like.

[0070] FIG. 7 is a flowchart illustrating the flow of operations of the first inspection unit 44 in the vehicle 10. The first inspection unit 44 starts the series of processes in FIG. 7, for example, when a predetermined time has elapsed since the vehicle 10 was started. The predetermined time is set, for example, to a time when the temperature of the battery 20 has become sufficiently high. Alternatively, the first inspection unit 44 may start the series of processes in FIG. 7 when the temperature of the battery 20 has become equal to or higher than a predetermined temperature since the vehicle 10 was started. Alternatively, the first inspection unit 44 may repeatedly perform the series of processes in FIG. 7 at a predetermined interval.

[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). Note that 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 being applied (S12). Then, the first inspection unit 44 determines whether the acquired output current Ids is equal to or less than a predetermined threshold value (S13).

[0073] If the output current Ids is equal to or less than the predetermined threshold value (YES in S13), the first inspection unit 44 ends the series of processes. In this case, since not many chloride ions are present in the gap 118 of the chloride ion detection sensor 30, which is disposed in a position where condensation is likely to occur, it is assumed that not many chloride ions are present throughout the battery pack 22. In other words, in this case, it is assumed that the battery pack 22 is unlikely to be corroded.

[0074] If the output current Ids is greater than the predetermined threshold value (NO in S13), the first inspection unit 44 determines that there is a possibility of corrosion of the battery pack 22 (S14). Then, the first inspection unit 44 causes the notification unit 34 to notify that there is a possibility of corrosion of the battery pack 22 (S15), and ends the series of processes. In this case, since a large number of chloride ions are present in the gap 118 of the chloride ion detection sensor 30, which is disposed in a position where condensation is likely to occur, it is assumed that a large number of chloride ions are also present throughout the battery pack 22. If a large number of chloride ions are present throughout the battery pack 22, it is assumed that there is a high possibility that the battery pack 22 is corroded, and therefore a notification to that effect is issued.

[0075] When the driver of the vehicle 10 recognizes the notification indicating that there is a possibility of corrosion in the battery pack 22, the driver takes the vehicle 10 to an inspection company and requests the inspection company to perform a detailed inspection.

[0076] Fig. 8 is a flowchart explaining the flow of inspection at the inspection company. The inspection company connects the vehicle-side interface 36 of the vehicle 10 that has been notified of the possibility of corrosion in the battery pack 22 to the external inspection device-side interface 50 of the external inspection device 12 with a cable. This enables the external inspection device 12 to control the first control device 32 of the vehicle 10 and obtain the detection results of the chloride ion detection sensor 30 of the vehicle 10. After that, a series of processes shown in Fig. 8 are performed.

[0077] First, the inspection company 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 for confirming whether a change in the output current Ids in response to a change in the second bias voltage Vgs is a hysteresis response. The flow of the hysteresis confirmation process will be described in detail later. Hereinafter, the hysteresis confirmation process performed after a notification indicating the possibility of corrosion of the battery pack 22, as in step S20, may be referred to as a first hysteresis confirmation process.

[0078] The second check unit 64 determines whether or not it has been determined that a hysteresis response will occur in the first hysteresis confirmation process, that is, the hysteresis confirmation process in step S20 (S21).

[0079] If it is not determined that a hysteresis response will occur (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 ends. In this case, although the notification unit 34 of the vehicle 10 has notified the user, it is assumed that there is no corrosion in the battery pack 22. Note that the second inspection unit 64 may clear the notification from the notification unit 34 of the vehicle 10.

[0080] If it is determined that a hysteresis response occurs (YES in S21), it is estimated that there is a possibility of corrosion of 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 temporarily clean the chloride ion detection sensor 30 (S23).

[0081] Upon receiving the cleaning instruction, the inspection company cleans the chloride ion detection sensor 30. For example, the inspection company prepares a cleaning device having a cleaning nozzle capable of discharging a cleaning agent such as water, a suction port capable of sucking in the cleaning agent, and a drying nozzle capable of discharging dry air. The inspection company inserts the cleaning nozzle of the cleaning device into the interior of 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 clean the chloride ion detection sensor 30 with the cleaning agent. The inspection company then operates the cleaning device to suck in the cleaning agent discharged into the interior of the battery pack 22 through the suction port. The inspection company then operates the cleaning device to discharge dry air from the drying nozzle to 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 exemplified method, and any method can be adopted. For example, the chloride ion detection sensor 30 may be detachably installed in the intake duct 80, the exhaust duct 82, or the battery pack 22. The inspection company may then remove the chloride ion detection sensor 30 from the vehicle 10, clean the chloride ion detection sensor 30, and then install the chloride ion detection sensor 30 in its original position after cleaning.

[0082] Here, if the battery pack 22 is corroded, it is assumed that there is a high possibility that chloride ions are present inside the battery pack 22. Therefore, in a situation where the battery pack 22 is corroded, even if the chloride ion detection sensor 30 is cleaned, chloride ions present inside the battery pack 22 will cause chloride ions to adhere to the chloride ion detection sensor 30 again.

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

[0084] The second check unit 64 determines whether or not it has been determined that a hysteresis response will occur in the second hysteresis confirmation process, that is, the hysteresis confirmation process of step S24 (S25).

[0085] If it is determined that the chloride ion detection sensor 30 exhibits a hysteresis response even after cleaning (YES in S25), it is highly likely that chloride ions are present inside the battery pack 22. Therefore, the second inspection unit 64 determines that corrosion exists in the battery pack 22 (S26). When the inspection company recognizes the determination result that corrosion exists in the battery pack 22, it replaces the battery pack 22 (S27) and ends the inspection.

[0086] If the result of the hysteresis confirmation process after cleaning the chloride ion detection sensor 30 indicates that the response is not hysteretic (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 it is initially determined in the first hysteresis confirmation process before cleaning that a hysteresis response will occur, it is assumed that the battery pack 22 is prone to corrosion. Therefore, the second inspection unit 64 changes the maintenance settings in the first control device 32 so as to strengthen maintenance regarding corrosion of the battery pack 22 (S29), and ends the inspection.

[0088] By changing the maintenance settings, the first inspection unit 44 of the vehicle 10 will not only perform inspections using the chloride ion detection sensor 30 regarding corrosion of the battery pack 22, but will also perform processing other than inspections using the chloride ion detection sensor 30.

[0089] For example, the first inspection unit 44 additionally performs a process of sequentially acquiring the outside air temperature and determining whether the outside air temperature has remained at or below a predetermined temperature for a predetermined period of time or longer. If the first inspection unit 44 determines that the outside air temperature has remained at or below the predetermined temperature for a predetermined period of time or longer, it determines that the battery pack 22 is in a state in which corrosion is likely to progress. If the first inspection unit 44 determines that the outside air temperature has remained at or below the predetermined temperature for a predetermined period of time or longer, it starts the series of processes shown in FIG. 7 even if the timing for executing the series of processes shown in FIG. 7 has not yet arrived. This makes it possible to detect the possibility of corrosion in the battery pack 22 at an early stage. Note that the specific content of the maintenance after reinforcement is not limited to the example and can be any content.

[0090] 9 is a diagram illustrating the flow of the hysteresis confirmation process. In both the first hysteresis confirmation process in step S20 and the second hysteresis confirmation process in step S24, a series of processes shown in FIG.

[0091] When the hysteresis checking process is started, the second checker 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 the second bias voltage Vgs is increased by a predetermined voltage increment from the minimum voltage Vgsmin to the maximum voltage Vgsmax, and then decreased by a predetermined voltage increment from the maximum voltage Vgsmax to the minimum voltage Vgsmin. The second inspection unit 64 determines the current second bias voltage Vgs in accordance with this order.

[0093] The second inspection unit 64 applies the determined second bias voltage Vgs to the reference electrode 116 (S42). Then, the second inspection unit 64 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 them in the second memory 62 (S44).

[0094] Next, the second checking unit 64 determines whether or not the measurement end condition is met (S45). For example, the second checking unit 64 determines that the measurement end condition is met when all determinations of the second bias voltages Vgs according to a predetermined determination order have been completed in step S41.

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

[0096] That is, the second test section 64 repeatedly applies the second bias voltage Vgs while changing it, and acquires the output current Ids every time the second bias voltage Vgs is changed.

[0097] If it is determined that the measurement termination condition is met (S45), the second inspection unit 64 derives a voltage range based on the measurement results (S46). For example, the second inspection unit 64 derives a difference value by subtracting the output current Ids at the minimum voltage Vgsmin (i.e., the minimum current Idsmin) from the output current Ids at the maximum voltage Vgsmax (i.e., the maximum current Idsmax). The second inspection unit 64 divides this difference value by 2 to derive the intermediate current Idxmid. The second inspection unit 64 references the measurement results stored in the second memory 62 and obtains the rising voltage Vgsu and falling voltage Vgsd corresponding to the intermediate current Idxmid. The second inspection unit 64 subtracts the falling voltage Vgsd from the rising voltage Vgsu to derive the voltage range.

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

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

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

[0101] Then, as described with reference to FIG. 8, the second inspection unit 64 determines whether the battery pack 22 is corroded based on the determination result of the hysteresis confirmation process.

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

[0103] 8, the hysteresis check process is performed twice in the inspection by the inspection company. By performing the hysteresis check process twice, it is possible to more accurately detect corrosion of the battery pack 22. However, the present invention is not limited to performing the hysteresis check process twice, and the hysteresis check process may be performed only once.

[0104] Fig. 10 is a flowchart showing an example in which the hysteresis confirmation process is performed only once. Fig. 10 corresponds to the flowchart of Fig. 8 in which the second hysteresis confirmation process is omitted. As shown in Fig. 10, if it is determined in the hysteresis confirmation process that a hysteresis response will occur (YES in S21), the second inspection unit 64 determines that corrosion exists in the battery pack 22 (S60). When the inspection company recognizes the determination result that corrosion exists in the battery pack 22, it replaces the battery pack 22 (S61) and ends the inspection.

[0105] In the mode in which the hysteresis checking process is performed only once, corrosion of the battery pack 22 can be detected with higher accuracy than in the mode in which the 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 when the output current Ids exceeds a predetermined threshold. Then, when 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 or not there is corrosion in the battery pack 22 based on the determination 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 alone. 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] Fig. 11 is a flowchart showing an example of a case where only the inspection is performed by the first inspection unit 44. As shown in Fig. 11, when the output current Ids is equal to or less than the predetermined threshold value (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 the predetermined threshold value (NO in S13), the first inspection unit 44 determines that there is corrosion in the battery pack 22 (S71). Then, the first inspection unit 44 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 inspection by the external inspection device 12, and the inspection burden on the inspection company can be reduced.

[0110] While the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such embodiments. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the claims, and it is understood that such modifications and alterations also fall within the technical scope of the present invention.

[0111] For example, in the above embodiment, the second control device 54 is 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 a hysteresis confirmation process. [Explanation of symbols]

[0112] 1. Inspection system 10 vehicles 20 Battery 22 Battery pack 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 end 92 Exhaust inlet end 100 Water storage unit 110 1st electrode 112 2nd electrode 114 Control electrode 116 Reference electrode 118 Gap Vgs Second bias voltage Ids Output current

Claims

1. a battery pack that houses a battery to be mounted on the vehicle; an intake duct that can guide air outside the vehicle into the battery pack to air-cool the battery; an exhaust duct that guides air inside the battery pack to the outside of the vehicle; one or more chloride ion detection sensors disposed inside the battery pack and capable of detecting chloride ions; a first control device; Equipped with The first control device one or more first processors; one or more first memories coupled to the first processor; and The first processor inspecting the battery pack for corrosion based on the detected value of the chloride ion detection sensor; An inspection system that performs a process including:

2. 2. The inspection system according to claim 1, wherein the at least one chloride ion detection sensor is disposed at a position near an end of the intake duct that opens into the interior of the battery pack and / or near an end of the exhaust duct that opens into the interior of the battery pack.

3. The battery pack At least a part of the inner surface of the bottom of the battery pack has a water storage portion recessed toward the outside of the battery pack, The inspection system of claim 1 , wherein the at least one chloride ion detection sensor is disposed at the water container.

4. The chloride ion detection sensor includes: a semiconductor sensor comprising a first electrode, a second electrode, a control electrode, and a reference electrode disposed with a predetermined gap from the control electrode, wherein the potential of the control electrode changes in accordance with a voltage applied to the reference electrode and a concentration of chloride ions present in the predetermined gap, and the current between the first electrode and the second electrode changes in accordance with the potential of the control electrode; detecting a current between the first electrode and the second electrode when a voltage is applied to the reference electrode as a detection value; The first processor determining that there is a possibility of corrosion of the battery pack when the detection value of the chloride ion detection sensor exceeds a predetermined threshold; The inspection system of claim 1 , wherein the inspection system performs a process comprising:

5. a second control device; The second control device is one or more second processors; one or more second memories coupled to the second processor; and The second processor When the first processor determines that there is a possibility of corrosion of the battery pack, a hysteresis confirmation process is performed in which a voltage applied to the reference electrode is changed and a change in current between the first electrode and the second electrode in response to the change in voltage applied to the reference electrode is determined to be a hysteresis response. determining corrosion of the battery pack based on a determination result of the hysteresis confirmation process; The inspection system of claim 4 , wherein the inspection system performs a process comprising:

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