Diagnostic system

Abstract

Properly assess the reusability of batteries. [Solution] The diagnostic system comprises a storage device 104, an internal pressure transition estimation unit 250, a damage amount calculation unit 255, and a service life prediction unit 260. The storage device 104 stores second history information 205, which shows the history of the battery's voltage, current, and temperature during the period the battery was installed in the vehicle. The damage amount calculation unit 255 estimates the transition of the battery's internal pressure, which changes according to the elapsed time since the start of battery use in the vehicle, according to the second history information 205. After the battery's use in the vehicle ends, the damage amount calculation unit 255 calculates the amount of damage to the battery's casing due to internal pressure over the above period, according to the estimation result of the internal pressure transition estimation unit 250. The service life prediction unit 260 predicts the length of the battery's service life when it is reused, according to usage condition information 217, which shows the usage conditions of the battery when it is reused after the end of use, and the amount of damage.

Description

Technical Field

[0001] This disclosure relates to a diagnostic system.

Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2020-061335 (Patent Document 1) discloses a vehicle including a battery, a storage device, an airbag, and a control device. The storage device stores the operation history of the airbag. The control device acquires information regarding the vibration or impact of the vehicle based on the above history. The control device evaluates (diagnoses) the reusability of the battery based on the acquired information.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The housing of the battery is liable to be damaged due to an increase in the internal pressure of the housing caused by gas generated inside the battery. In Patent Document 1, damage to the housing caused by such an increase in internal pressure is not examined. As a result, it may be misdiagnosed that the battery is reusable when the battery is actually not reusable.

[0005] This disclosure has been made to solve the above problems, and an object thereof is to provide a diagnostic system capable of appropriately diagnosing the reusability of a battery.

Means for Solving the Problems

[0006] The diagnostic system described herein is used to diagnose the reusability of a battery. The diagnostic system comprises a storage unit, an estimation unit, a calculation unit, and a prediction unit. The storage unit stores historical information showing the history of the battery's voltage, current, and temperature during the period the battery was installed in a vehicle. The estimation unit estimates the change in the battery's internal pressure, which changes according to the elapsed time since the start of battery use in the vehicle, according to the historical information. After the battery's use in the vehicle is completed, the calculation unit calculates the amount of damage to the battery's casing due to internal pressure over the period, according to the estimation results of the estimation unit. The prediction unit predicts the length of the battery's service life when it is reused, according to usage condition information showing the battery's usage conditions when it is reused after its use is completed, and the amount of damage.

[0007] With the above configuration, the amount of damage to the casing is calculated according to the change in internal pressure of the casing from the start of battery use. Then, the length of the battery's lifespan when reused is predicted according to the usage conditions when the battery is reused and the amount of damage described above. As a result, the length of the battery's lifespan when reused can be predicted with high accuracy according to the usage conditions and the degree of damage to the casing due to internal pressure. Therefore, the reusability of the battery can be appropriately diagnosed according to the lifespan prediction result.

[0008] The usage conditions information may include predicted values ​​for the maximum SOC and maximum temperature of the battery when reused. The memory unit may further store a plurality of predetermined first relationships. The plurality of first relationships show the relationship between the predicted values ​​for maximum SOC and maximum temperature and the length of the service life for each amount of damage. The prediction unit may select a relationship corresponding to the amount of damage from among the plurality of first relationships and use the selected relationship to predict the length of the service life according to the predicted values ​​for maximum SOC and maximum temperature.

[0009] The diagnostic system may further include a command output unit. The command output unit outputs a command instructing the implementation of predetermined measures to relieve internal pressure if the length of the service life predicted by the prediction unit is less than the target length of the service life.

[0010] The increase in the amount of damage described above is smaller the lower the internal pressure. With the above configuration, if the predicted service life is less than the target service life, the user is prompted to take predetermined measures. This relieves the internal pressure of the housing, thereby reducing the rate of increase in damage. As a result, the time until the amount of damage reaches its limit can be extended. Therefore, even if the length of service life predicted by the first prediction unit is less than the target length, the service life can be extended to the target length or beyond, restoring the remaining value of the battery and enabling battery reuse.

[0011] The prescribed measures may include storing the battery for a predetermined relaxation period under at least one of the first, second, and third conditions. The length of the relaxation period is determined as the length of time required to relax the internal pressure and extend the service life to a target length or longer. The first condition is that the ambient temperature of the battery is below a reference temperature. The second condition is that the ambient pressure of the battery is below the internal pressure after the battery has been used in the vehicle. The third condition is that the space surrounding the battery is filled with a gas different from the gas inside the housing.

[0012] The estimation unit may estimate the increase in internal pressure from the start of use to the end of use according to the estimation results of the changes. The memory unit may further store a second relationship showing a predetermined relationship between the amount of damage and the amount of increase and the length of the relaxation period. The diagnostic system may further include a determination unit that uses the second relationship to determine the length of the relaxation period according to the amount of increase and the amount of damage. [Effects of the Invention]

[0013] According to this disclosure, the reusability of batteries can be properly assessed. [Brief explanation of the drawing]

[0014] [Figure 1] This diagram shows the overall configuration of a diagnostic system according to the embodiment. [Figure 2]This is a block diagram representing the data stored in the memory device and the functional configuration of the control device. [Figure 3] This diagram illustrates the data structure of a map. [Figure 4] This diagram illustrates a set of maps and the data structure of those maps. [Figure 5] This figure illustrates an example of the changes in internal pressure and damage amount in an embodiment and a comparative example thereof. [Figure 6] This flowchart illustrates the procedure for processing performed by the terminal device in the embodiment. [Modes for carrying out the invention]

[0015] Embodiments of this disclosure will be described in detail below with reference to the drawings. The same or corresponding parts in the drawings will be denoted by the same reference numerals and their descriptions will not be repeated. Each embodiment and its modifications may be combined with one another as appropriate.

[0016] Figure 1 is a diagram showing the overall configuration of a diagnostic system according to an embodiment. Referring to Figure 1, the diagnostic system 1 comprises a vehicle 10 and a terminal device 100.

[0017] Vehicle 10 is an electric vehicle such as a BEV (Battery Electric Vehicle), and includes a power storage device 20, a sensor group 30, a drive unit 40, a connector 45, and an ECU (Electronic Control Unit) 50.

[0018] The energy storage device 20 includes a plurality of batteries 24. Each battery 24 is a cell that stores power for the running of the vehicle 10, and includes a battery case 26, an electrode body having a positive electrode and a negative electrode, and an electrolytic solution. The battery case 26 is a housing that houses the electrode body. Each battery 24 generates a gas such as carbon dioxide inside the battery 24 due to a chemical reaction accompanying its charge and discharge. Each battery 24 generates more gas as its electrode body deteriorates. The gas generation rate depends on the temperature etc. of each battery 24. The gas generation can be a factor that raises the internal pressure of the battery 24.

[0019] The battery case 26 includes a gas discharge valve and a sealing member (both not shown). The gas discharge valve can be opened when the internal pressure of the battery 24 rises excessively. The sealing member can allow the above gas to permeate to the outside of the battery case 26. The gas permeation can be a factor that lowers the internal pressure of the battery 24. The gas permeation amount depends on, for example, the temperature of the battery 24.

[0020] The sensor group 30 includes a voltage sensor 32, a current sensor 34, and a temperature sensor 36. These sensors respectively detect the voltage VB, current IB, and temperature TB of the battery 24. The drive device 40 includes an inverter and a motor (both not shown), and generates a running driving force for the vehicle 1 by consuming the power of each battery 24. The connector 45 can be connected to external devices of the vehicle 10.

[0021] The ECU 50 includes a control device 51, a processing device 52, a storage device 53, and a communication device 54. The control device 51 controls the drive device 40 to control the charge and discharge of the battery 24.

[0022] The processing unit 52 includes memory and a processor (neither of which are shown). The memory includes ROM (Read Only Memory) and RAM (Random Access Memory). The processor is, for example, a CPU (Central Processing Unit) which performs various arithmetic operations according to a program stored in ROM. The processing unit 52 sequentially calculates the State of Charge (SOC) of the battery 24 based on, for example, voltage VB, current IB, and temperature TB.

[0023] The storage device 53 stores first history information 55 and second history information 56. The first history information 55 indicates items of the various process history of the battery 24 and includes void volume information, inspection result information, and elapsed time information. The void volume information indicates the volume of voids inside the battery case 26. This void volume is determined by subtracting the sum of the volumes of the electrodes and electrolytes of each battery 24 from the volume of the battery case 26. The inspection result information indicates the result of the airtightness inspection of the battery 24. The elapsed time information indicates the elapsed time since the start of use of the battery 24 in the vehicle 10 (delivery of the vehicle 10 to the user). This elapsed time is determined, for example, in months or years.

[0024] The second history information 56 includes the history of voltage VB, current IB, temperature TB, and state of charge (SOC) during the period when the battery 24 is installed in the vehicle 10 (hereinafter also referred to as the "vehicle installation period"). The history of temperature TB includes the temperature frequency, which represents the frequency (time) at which temperature TB took each temperature value. The history of SOC includes the SOC frequency, which represents the frequency (time) at which SOC took each value. The communication device 54 can transmit the first history information 55 and the second history information 56 to an external server.

[0025] The terminal device 100 is a maintenance terminal for dealers and the like, and includes a communication device 102, a storage device 104, an input device 106, a display device 108, and a control device 110.

[0026] The communication device 102 acquires first history information 55 and second history information 56 from the vehicle 10's storage device 53 via a communication cable connected to the connector 45. If this information is stored in the external server mentioned above, the communication device 102 may acquire this information from the server via wired or wireless communication. The storage device 104 corresponds to an example of the “storage unit” in this disclosure and stores the acquired first history information 55 and second history information 56 as first history information 202 and second history information 205 (Figure 2), respectively.

[0027] The input device 106 receives various user operations. The display device 108 displays various screens. The control device 110 controls the display device 108. The control device 110 includes memory and a processor (neither shown). The memory includes ROM and RAM. The processor is, for example, a CPU, which performs various arithmetic operations according to the program stored in the ROM. As a result, the control device 110 functions as a processing unit that performs various operations.

[0028] After being used in the vehicle 10, the battery 24 may be removed from the vehicle 10 by a dealer or the like. Subsequently, if the battery 24 is reusable, it may be reused for a desired purpose. Therefore, it is important to properly assess the reusability of the battery 24.

[0029] During its time in the vehicle, the battery case 26 is susceptible to damage due to the increase in internal pressure of the battery 24 caused by gases generated inside the battery 24. This damage increases over time. The internal pressure changes according to the elapsed time since the battery 24 began to be used in the vehicle 10, and generally increases over the long term. As the damage to the battery case 26 due to internal pressure increases, the battery case 26 may become damaged due to fatigue and break. As a result, it may become difficult to reuse the battery 24.

[0030] Therefore, the terminal device 100 of the diagnostic system 1 according to this embodiment is configured to appropriately diagnose the reusability of the battery 24 and to enable the reuse of the battery 24. This point will be explained below.

[0031] Figure 2 is a block diagram showing the data stored in the storage device 104 and the functional configuration of the control device 110. Referring to Figure 2, the storage device 104 stores first history information 202, second history information 205, maps 210 and 220, map group 215, and usage condition information 217.

[0032] The first history information 202 and the second history information 205 are the same as those stored in the storage device 53 of the ECU 50. Maps 210, 220, map group 215, and usage condition information 217 will be described later.

[0033] The control device 110 includes, as its functional configuration, an internal pressure transition estimation unit 250, a damage amount calculation unit 255, a service life prediction unit 260, a diagnostic unit 265, a diagnostic result output unit 267, a relaxation period determination unit 270, and a command output unit 275. These functions are realized when the processor of the control device 110 executes a program stored in ROM.

[0034] The internal pressure transition estimation unit 250 estimates the internal pressure transition of the battery 24 according to the first history information 202 and the second history information 205 as follows.

[0035] The internal pressure transition estimation unit 250 estimates the gas generation rate of the battery 24 at each timing during the vehicle installation period, for example, according to the SOC and temperature TB indicated by the second history information 205. The internal pressure transition estimation unit 250 estimates the rate of increase of the internal pressure of the battery 24 at each timing according to the estimated gas generation rate and the void volume information of the first history information 202. As a result, the internal pressure transition estimation unit 250 estimates the amount of increase in internal pressure at each timing according to the rate of increase of internal pressure and the elapsed time at each timing. This amount of increase is estimated, for example, by multiplying the rate of increase of internal pressure by the square root of the elapsed time. The internal pressure transition estimation unit 250 estimates the transition of the internal pressure of the battery 24 during the vehicle installation period according to a predetermined initial reference value of internal pressure and the amount of increase of internal pressure. Based on these estimation results, the internal pressure transition estimation unit 250 can estimate the total increase in internal pressure over the vehicle installation period (hereinafter also referred to as the "total internal pressure increase"). The total internal pressure increase corresponds to the increase in internal pressure P from the start of use of the battery 24 in the vehicle 10 to the end of use of the battery 24.

[0036] The internal pressure transition estimation unit 250 may estimate the rate of decrease in internal pressure by estimating the amount of gas permeating from the battery case 26 based on the temperature TB history. In this case, the internal pressure transition estimation unit 250 estimates the amount of decrease in internal pressure according to the rate of decrease in internal pressure and the elapsed time. This amount of decrease is estimated, for example, by multiplying the rate of decrease in internal pressure by the elapsed time. The internal pressure transition estimation unit 250 may then estimate the total increase in internal pressure by calculating the difference between the increase and decrease in internal pressure estimated as described above.

[0037] The internal pressure transition estimation unit 250 may correct the estimated result of the internal pressure transition according to the inspection result information of the first history information 202. Alternatively, the internal pressure transition estimation unit 250 may estimate the transition of the amount of gas permeate from the sealing member according to the history of temperature TB, and correct the estimated result of the internal pressure transition according to that estimation result.

[0038] The damage amount calculation unit 255 calculates the amount of damage (hereinafter also simply referred to as "damage amount") to the battery case 26 due to the internal pressure of the battery 24 during its period of installation in the vehicle, after the battery 24 has finished being used in the vehicle 10. As described below, the damage amount calculation unit 255 uses the map 210 to calculate the damage amount according to the estimation results of the internal pressure transition estimation unit 250.

[0039] Figure 3 illustrates the data structure of map 210. Referring to Figure 3, map 210 represents the relationship between the internal pressure P of the battery 24, the duration CT of that internal pressure P, and the increase in damage over the duration CT. For example, if the internal pressure P remains at P1 for a duration of CT1, the damage calculation unit 255 calculates the increase in damage as d11. Subsequently, if the internal pressure P remains at P2 (>P1) for a duration of CT2, the damage calculation unit 255 calculates the increase in damage as d22. The damage calculation unit 255 calculates the total damage over the vehicle installation period by accumulating these calculated increases. The initial value of the damage is, for example, zero. Map 210 is determined in advance as appropriate through prior evaluation tests, etc. Note that the increase in damage per unit time (increase rate) is smaller the lower the internal pressure P. In other words, the battery case 26 is less susceptible to damage from internal pressure P the lower the internal pressure P is.

[0040] Referring again to Figure 2, the service life prediction unit 260 predicts the length of the service life of the battery 24 when it is reused, according to the amount of damage calculated as described above and the usage condition information 217. This period is also called the "reuse service life". The usage condition information 217 indicates the usage conditions of the battery 24 when it is reused after its use in the vehicle 10 has ended. The usage condition information 217 is appropriately predetermined by user operation using the input device 106. The usage condition information 217 is, for example, a predicted value of the maximum SOC and maximum temperature when the battery 24 is reused, but is not limited to this. The above predicted values ​​may be replaced by the set values ​​or allowable values ​​of the maximum SOC and maximum temperature described above. As will be explained below, the damage amount calculation unit 255 predicts the length of the reuse service life using the map group 215.

[0041] Figure 4 illustrates the data structure of map group 215 and map 220. Referring to Figure 4, map group 215 includes maps 216_1, 216_2, 216_3, etc. These maps show the relationship between the predicted maximum SOC and maximum temperature when the battery 24 is reused and the length of its reuse life, for each damage level. The predicted maximum SOC and maximum temperature are predetermined as appropriate based on the intended use of the battery 24 when it is reused.

[0042] For example, if the amount of damage is calculated to be D3, the service life prediction unit 260 selects map 216_3 from the map group 215. Then, using map 216_3, the service life prediction unit 260 predicts the length of the reuse service life of the battery 24 according to the predicted values ​​of the maximum SOC and maximum temperature when the battery 24 is reused. In one example, if the predicted values ​​of the maximum SOC and maximum temperature are X1 and TM1, respectively, the service life prediction unit 260 uses map 216_3 to predict that the length of the reuse service life is LT11.

[0043] According to the service life prediction unit 260, the length of the reuse service life is predicted according to the usage conditions when the battery 24 is reused and the degree of damage to the battery case 26 due to the internal pressure P. This makes it possible to predict the length of the reuse service life with high accuracy.

[0044] Referring again to Figure 2, the diagnostic unit 265 switches its processing depending on whether the length of the reusable service life predicted by the service life prediction unit 260 is equal to or greater than the target length of the reusable service life. This target length is appropriately predetermined based on the intended use of the battery 24 at the time of reuse. If the predicted length of the reusable service life is equal to or greater than the target length, the diagnostic unit 265 diagnoses that the battery 24 is reusable. On the other hand, if the predicted length of the reusable service life is less than the target length, the diagnostic unit 265 diagnoses that it is difficult to reuse the battery 24. In this way, the diagnostic unit 265 can appropriately diagnose the reusability of the battery 24 according to the predicted result of the reusable service life.

[0045] If the battery 24 is diagnosed as reusable, the diagnostic result output unit 267 generates a command to the display device 108 to output (display) the diagnostic result. As a result, the diagnostic result is displayed on the display device 108 and notified to the user. Consequently, the battery 24 is reused for the desired application. For example, the reused battery 24 is incorporated into a recycled product, which is then sold.

[0046] On the other hand, if it is determined that the battery 24 is difficult to reuse, it may not be possible to reuse the battery 24 as described above because its reuse lifespan is insufficient. However, even in such cases, the reuse lifespan can be extended by easing the internal pressure P through the implementation of prescribed internal pressure relief measures. Internal pressure relief measures involve storing the battery 24 for a predetermined period under appropriate conditions to relieve (reduce) the internal pressure P. Details of the above conditions will be explained in detail later. The above predetermined period is also referred to as the "relaxation period". The advantages of internal pressure relief measures will be explained below.

[0047] Figure 5 illustrates an example of the changes in internal pressure P and damage amount in the embodiment and its comparative example. In the embodiment, the battery 24 is removed from the vehicle 10, internal pressure relief measures are taken, and then the battery 24 is reused. In the comparative example, the battery 24 is removed from the vehicle 10 and immediately reused without any internal pressure relief measures being taken.

[0048] Referring to Figure 5, lines 310 and 315 represent the changes in internal pressure P and damage amount D in the embodiment, respectively. Lines 320 and 325 represent the changes in internal pressure P and damage amount D in the comparative example, respectively.

[0049] Period T1 corresponds to the vehicle installation period and is defined as the period from time t0 to time t1. At time t0, use of the battery 24 begins in the vehicle 10. At time t1, use of the battery 24 in the vehicle 10 ends, and the battery 24 is removed from the vehicle 10. During period T1, there is no difference in internal pressure P and damage amount D between the embodiment and the comparative example. For example, in both the embodiment and the comparative example, at time t1, the internal pressure P is P1 and the damage amount D is D1.

[0050] In the comparative example, after the battery 24 is removed from the vehicle 10, it is immediately reused for a period T2a. Period T2a is the period from time t1 to time t2a. As mentioned above, the higher the internal pressure P, the higher the rate of increase in the amount of damage D, and the internal pressure P (P1) at time t1 is relatively high (line 320). Therefore, the amount of damage D tends to increase during period T2a, reaching the critical damage amount LM at time t2a (line 325). As a result, the length of the reuse life in the comparative example is only L2a.

[0051] On the other hand, in this embodiment, internal pressure relief measures are implemented during period Ta, and then the battery 24 is reused during period T2. Period Ta is the period from time t1 to time ta, and corresponds to the aforementioned relief period. Period T2 is the period from time ta to time t2. The internal pressure relief measures relieve the internal pressure P, reducing it from P1 to Pa. Because the internal pressure P (Pa) at time ta is relatively low (line 310), the rate of increase in the amount of damage D during period T2 is low (line 315). In other words, the amount of damage D increases less while the battery 24 is reused compared to the comparative example. As a result, the length of the reuse service life is L2 (>L2a). L2 is assumed to be longer than the target length of the reuse service life.

[0052] Thus, in this embodiment, the length of the reuse service life can be extended to exceed the target length by the internal pressure relief measure. Therefore, even if the length of the reuse service life predicted by the service life prediction unit 260 is less than the target length, the internal pressure relief measure can restore the remaining value of the battery 24, making it possible to reuse the battery 24.

[0053] Referring again to Figure 4, Map 220 shows the relationship between the amount of damage D, the total increase in internal pressure, and the length of the relaxation period. In Map 220, the length of the relaxation period is determined as the length of time required to relax the internal pressure P and extend the reuse lifespan to or above the target length. Note that "Impossible" in the figure means that, depending on the combination of the amount of damage D and the total increase in internal pressure, even if internal pressure relaxation measures are implemented, the reuse lifespan cannot reach the target length. In other words, "Impossible" indicates that the length of the relaxation period cannot be determined for the corresponding combination of the amount of damage D and the total increase in internal pressure. Map 220 is determined in advance as appropriate through experiments, etc.

[0054] Referring again to Figure 2, the relaxation period determination unit 270 uses the map 220 to determine the length of the relaxation period according to the total internal pressure increase after the battery 24 in the vehicle 10 has finished being used and the amount of damage D. For example, if the total internal pressure increase is ΔP1 and the amount of damage D is D1, the relaxation period determination unit 270 determines the length of the relaxation period to be LN11 (see Figure 4). Note that if the length of the service life corresponding to the total internal pressure increase and the amount of damage D in the map 220 indicates "unavailable", the relaxation period determination unit 270 determines that it is not possible to determine the length of the relaxation period.

[0055] Map 220 may be defined for each item of the process history indicated by the first history information 202, or for each usage condition indicated by the usage condition information 217. This allows for a more appropriate determination of the length of the relaxation period according to the process history of the battery 24 or the usage conditions when it is reused.

[0056] The command output unit 275 outputs a command instructing the user of the diagnostic system 1 to implement internal pressure relief measures when the predicted reuse lifespan is less than the target length and the length of the relaxation period can be determined. This user is, for example, a dealer's mechanic. The above command is output to display, for example, a screen on the display device 108 instructing the user to implement internal pressure relief measures. As a result, the user is prompted to implement internal pressure relief measures because such a screen is displayed on the display device 108. As a result, the reuse lifespan can be extended beyond the target length, as explained in Figure 5. If the length of the relaxation period can be determined as described above, the diagnostic unit 265 diagnoses that the battery 24 is reusable. On the other hand, if the length of the relaxation period cannot be determined, the diagnostic unit 265 diagnoses that it is difficult to reuse the battery 24.

[0057] The internal pressure relief measures are described in detail below. The internal pressure relief measures correspond to storing the battery 24 over a relief period under at least one of the following conditions 1, 2, and 3. Condition 1 is that the ambient temperature of the battery 24 is lower than the reference temperature. The reference temperature is, for example, zero degrees Celsius. Condition 2 is that the ambient pressure of the battery 24 is less than or equal to the internal pressure P after the battery 24 has finished being used in the vehicle 10 (i.e., after the vehicle installation period). Condition 3 is that the space surrounding the battery 24 is filled with a gas different from the gas in the battery case 26 (for example, nitrogen gas).

[0058] Under the first condition, gas generation reactions and electrode degradation of the battery 24 are suppressed. This reduces the rate at which the internal pressure P rises. In addition, under the first condition, because the temperature is low, even if the internal pressure P rises, the amount of damage D does not increase easily. Under the second condition, the amount of gas generated inside each battery 24 that permeates to the outside of the battery case 26 increases. This makes it easier for the internal pressure P to decrease due to gas leakage. Under the third condition, the gas inside the battery case 26 can permeate to the outside due to the difference between the partial pressure of the gas inside the battery case 26, such as carbon dioxide, and the pressure of the gas in the surrounding space which is different from that gas. From the above, by storing the battery 24 under at least one of the first to third conditions, the internal pressure P can be mitigated and the rate of increase in the amount of damage D can be reduced. This makes it possible to appropriately extend the reuse lifespan and reuse the battery 24.

[0059] Figure 6 is a flowchart illustrating the procedure of processing performed by the terminal device 100 in the embodiment. This flowchart starts when the terminal device 100 is connected to the connector 45 via a communication cable. At the start of this flowchart, the battery 24 may have already been removed from the vehicle 10 or may still be installed in the vehicle 10 within the energy storage device 20.

[0060] Referring to Figure 6, the terminal device 100 acquires first history information 55 from the vehicle 10 and stores it in the storage device 104 as first history information 202 (S10). The terminal device 100 acquires second history information 56 from the vehicle 10 and stores it in the storage device 104 as second history information 205 (S15). The terminal device 100 estimates the change in the internal pressure P of the battery 24 during the vehicle installation period according to the first history information 202 and the second history information 205 (S20). The terminal device 100 uses the map 210 to calculate the amount of damage D according to the estimation result in S20 (S25). The terminal device 100 receives user input to specify usage condition information 217 indicating the usage conditions when the battery 24 is reused (S30). In this example, the usage condition information 217 are predicted values ​​of maximum SOC and maximum temperature. The terminal device 100 predicts the reuse lifespan according to the usage condition information 217 and the amount of damage D using the map group 215 (S35).

[0061] The terminal device 100 switches processing according to whether the predicted reusable lifespan is greater than or equal to the target length (S40). If the predicted reusable lifespan is greater than or equal to the target length (YES in S40), the terminal device 100 diagnoses that the battery 24 is reusable (S42). After S42, the terminal device 100 displays a screen on the display device 108 showing the diagnosis result of S42 and terminates processing. If the predicted reusable lifespan is less than the target length (NO in S40), the terminal device 100 switches processing according to whether the length of the easing period can be determined using the map 220 (S45).

[0062] If the terminal device 100 cannot determine the length of the relaxation period (NO in S45), it diagnoses that the battery 24 is difficult to reuse (S47). After S47, the terminal device 100 displays a screen on the display device 108 showing the diagnosis result from S47 and terminates the process. On the other hand, if the terminal device 100 can determine the length of the relaxation period (YES in S45), it determines the length of the reuse service life corresponding to the total internal pressure rise and the amount of damage D (S50). The terminal device 100 then diagnoses that the battery 24 is reusable (S52). Next, the terminal device 100 outputs a command to the display device 108 instructing the user to implement internal pressure relaxation measures (S55), and displays a screen on the display device 108 instructing the user to implement the measures.

[0063] As described above, according to the embodiment, the length of the reusable lifespan can be accurately predicted based on the amount of damage D due to internal pressure P. This allows for an appropriate diagnosis of the reusability of the battery 24. Furthermore, if the predicted length of the reusable lifespan is less than the target length, the user is prompted to implement internal pressure relief measures. As a result, the length of the reusable lifespan can be appropriately extended to exceed the target length. Therefore, the residual value of the battery 24 can be restored, making the battery 24 reusable.

[0064] [Other variations] The terminal device 100 may calculate the internal pressure P and the amount of damage D according to the first history information 55 and the second history information 56 of the storage device 53 of the ECU 50. In this case, the storage devices 53 and 104 correspond to an example of the “storage unit” of this disclosure.

[0065] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0066] 1 Diagnostic system, 10 Vehicle, 20 Energy storage device, 24 Battery, 26 Battery case, 30 Sensor group, 51,110 Control device, 52 Processing device, 53,104 Memory device, 54,102 Communication device, 100 Terminal device, 250 Internal pressure change estimation unit, 255 Damage amount calculation unit, 260 Service life prediction unit, 265 Diagnostic unit, 267 Diagnostic result output unit, 270 Relaxation period determination unit, 275 Command output unit.

Claims

1. A diagnostic system for diagnosing the reusability of batteries, A storage unit that stores historical information showing the voltage, current, and temperature history of the battery during the period the battery was installed in the vehicle, An estimation unit that estimates the change in the internal pressure of the battery, which changes according to the elapsed time since the start of use of the battery in the vehicle, according to the historical information, A calculation unit calculates, after the use of the battery in the vehicle has ended, the amount of damage to the battery housing due to the internal pressure over the said period, according to the estimation result of the estimation unit, A diagnostic system comprising: usage condition information indicating the usage conditions of the battery when it is reused after the end of use; and a prediction unit that predicts the length of the battery's service life when it is reused, based on the amount of damage.

2. The aforementioned usage condition information includes predicted values ​​for the maximum SOC and maximum temperature of the battery during reuse. The memory unit further stores a plurality of predetermined first relationships, the plurality of first relationships showing the relationship between the predicted values ​​of the maximum SOC and the maximum temperature and the length of the service life for each amount of damage, The prediction unit, From among the plurality of first relationships, select the relationship corresponding to the amount of damage, The diagnostic system according to claim 1, which uses the selected relationship to predict the length of the service life according to the predicted values ​​of the maximum SOC and the maximum temperature.

3. The diagnostic system according to claim 1 or 2, further comprising a command output unit that outputs a command instructing the implementation of predetermined measures to relieve the internal pressure if the length of the service life predicted by the prediction unit is less than the target length of the service life.

4. The aforementioned prescribed measures include measures to store the battery for a predetermined relaxation period under at least one of the first, second, and third conditions, The length of the relaxation period is determined as the length of the period required to relax the internal pressure and extend the service life to a length equal to or greater than the target length. The first condition is that the ambient temperature of the battery is lower than the reference temperature. The second condition is that the ambient pressure of the battery is less than or equal to the internal pressure after the battery has finished being used in the vehicle. The diagnostic system according to claim 3, wherein the third condition is that the space surrounding the battery is filled with a gas different from the gas inside the housing.

5. The estimation unit estimates the amount of increase in internal pressure from the start of use to the end of use according to the estimation result of the change, The memory unit further stores a second relationship that shows a predetermined relationship between the amount of damage and the amount of increase and the length of the relaxation period. The diagnostic system according to claim 4, further comprising a determination unit that uses the second relationship to determine the length of the relaxation period according to the amount of increase and the amount of damage.

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