Diagnostic system

Abstract

The diagnostic system includes a storage device, an internal pressure transition estimation section, a damage amount calculation section, and a durability prediction section. The storage device stores second historical information. The internal pressure transition estimation unit estimates a transition in the internal pressure of the battery. The damage amount calculation unit calculates the amount of damage to the housing of the battery by the internal pressure in accordance with the estimation result of the internal pressure transition estimation unit after the use of the battery in the vehicle is completed. The durability prediction unit predicts the length of the durability during repeated use of the battery on the basis of the use condition information and the damage amount. The use condition information indicates a use condition applied to the battery when the battery is repeatedly used after the end of use.

Description

Technical Field

[0001] This disclosure relates to diagnostic systems. Background Technology

[0002] Japanese Unexamined Patent Application Publication No. 2020-061335 (JP2020-061335A) discloses a vehicle including a battery, a storage device, an airbag, and a control device. The storage device stores the deployment history of the airbag. The control device obtains information about vibrations or impacts to the vehicle based on this history. The control device evaluates (diagnoses) the reusability of the battery based on the obtained information. Summary of the Invention

[0003] Gas generated inside the battery increases the internal pressure of the casing, making it susceptible to damage. JP2020-061335A does not address this type of casing damage caused by increased internal pressure. Therefore, even when a battery is not actually reusable, it may be incorrectly diagnosed as reusable.

[0004] This disclosure aims to solve the problems described above. The purpose of this disclosure is to provide a diagnostic system capable of appropriately diagnosing the reusability of a battery.

[0005] The diagnostic system disclosed herein is used to diagnose the reusability of a battery. The diagnostic system includes a storage unit, an estimation unit, a calculation unit, and a prediction unit. The storage unit is configured to store historical information indicating the battery's voltage, current, and temperature during the period the battery was installed in a vehicle. The estimation unit is configured to estimate changes in the battery's internal pressure based on the historical information. The internal pressure changes over time elapsed since the battery began being used in the vehicle. The calculation unit is configured to calculate, based on the estimation results from the estimation unit, the amount of damage caused by the internal pressure to the battery casing during that period after the battery's use in the vehicle has ended. The prediction unit is configured to predict the length of the battery's lifespan during repeated use based on usage condition information and the amount of damage. The usage condition information indicates the usage conditions applied to the battery when it is reused after the initial use.

[0006] Based on this configuration, the amount of damage to the casing is calculated according to the changes in internal pressure from the start of battery use. Then, based on the usage conditions and amount of damage during repeated use, the battery's lifespan during repeated use is predicted. By accurately predicting the battery's lifespan during repeated use based on usage conditions and the degree of damage to the casing caused by internal pressure, the battery's reusability can be appropriately diagnosed based on the predicted lifespan.

[0007] Usage condition information may include predicted values ​​of the battery's maximum SOC and maximum temperature during repeated use. The storage unit may also store multiple predefined first relationships. Each of these first relationships indicates a relationship between the predicted maximum SOC and maximum temperature and the length of the battery's lifespan for each damage level. The prediction unit can select a relationship corresponding to the damage level from the first relationships and, based on the predicted maximum SOC and maximum temperature, use the selected relationship to predict the length of the battery's lifespan.

[0008] The diagnostic system may also include a command output unit. The command output unit can be configured to output commands instructing predetermined measures to alleviate internal stress if the predicted service life is less than the target service life.

[0009] The lower the internal pressure, the smaller the increase in damage. Based on this configuration, if the predicted lifespan is less than the target lifespan, the user is prompted to take predetermined measures. This alleviates the internal pressure within the casing, thereby reducing the rate of increase in damage. Therefore, the time before damage reaches its limit can be extended. Thus, even if the predicted lifespan is less than the target lifespan, the lifespan can be made greater than or equal to the target lifespan, restoring the battery's remaining value and allowing for battery reuse.

[0010] The predetermined measures may include storing the battery beyond a predetermined relief period under at least one of the first, second, and third conditions. The length of the relief period can be determined as the length of the period during which internal pressure is relieved so that the length of the service life is greater than or equal to the target length. The first condition may be a condition where the temperature around the battery is below a reference temperature. The second condition may be a condition where the pressure around the battery is below or equal to the internal pressure of the battery after its use in the vehicle has ended. The third condition may be a condition where the space around the battery is filled with a gas different from the gas inside the casing.

[0011] The estimation unit can estimate the increase in internal pressure from the start to the end of use based on the estimation results of the transformation. The storage unit can also store a second relationship indicating the relationship between the damage amount and the increase amount and the length of the mitigation period. This relationship is predefined. The diagnostic system may also include a determination unit configured to determine the length of the mitigation period based on the increase amount and the damage amount using the second relationship.

[0012] According to this disclosure, the reusability of a battery can be appropriately diagnosed. Attached Figure Description

[0013] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, wherein similar symbols denote similar elements, and wherein: Figure 1 This is a diagram illustrating the overall configuration of the diagnostic system according to an embodiment; Figure 2 It is a block diagram illustrating the data stored in the storage device and the functional components of the control device. Figure 3 It is a graph that illustrates the data structure of the mapping. Figure 4 It is a diagram illustrating the data structure of mapping groups and mappings. Figure 5 This is a diagram illustrating examples of changes in internal pressure and damage levels in the embodiments and their comparative examples. Figure 6 This is a flowchart illustrating the processing procedure performed by the terminal device in an exemplary embodiment. Detailed Implementation

[0014] Embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. Identical or corresponding parts in the drawings will be indicated by the same reference numerals and will not be described again. Embodiments and their various modifications can be combined as appropriate.

[0015] Figure 1 This is a diagram illustrating the overall configuration of a diagnostic system according to an embodiment. (When referring to...) Figure 1 At that time, the diagnostic system 1 includes a vehicle 10 and a terminal device 100.

[0016] Vehicle 10 is an electric vehicle, such as a battery electric vehicle (BEV), and includes an energy storage device 20, a sensor group 30, a drive unit 40, a connector 45, and an electronic control unit (ECU) 50.

[0017] The power storage device 20 includes multiple batteries 24. Each of the batteries 24 is a single battery cell that stores electricity for the operation of the vehicle 10. Each battery 24 includes a battery casing 26, electrodes including a positive and a negative electrode, and an electrolyte. The battery casing 26 is a housing for the electrodes. Each of the batteries 24 produces gas (e.g., carbon dioxide) within itself due to chemical reactions that occur during charging or discharging. The more deteriorated the electrodes of each battery 24, the more gas is produced. The rate of gas production depends on factors such as the temperature of each battery 24. Gas production may be a factor contributing to increased internal pressure within the battery 24.

[0018] The battery housing 26 includes a gas vent valve and a sealing member (neither shown). The vent valve can be opened in the event of an excessive increase in internal pressure of the battery 24. The sealing member allows gas to be transferred to the outside of the battery housing 26. This gas transfer may be a factor in reducing the internal pressure of the battery 24. The amount of gas transferred depends, for example, on the temperature of the battery 24.

[0019] Sensor group 30 includes voltage sensor 32, current sensor 34, and temperature sensor 36. Each sensor detects the voltage VB, current IB, and temperature TB of battery 24. Drive unit 40 includes an inverter and an electric motor (neither shown), and generates traction driving force for vehicle 10 by consuming power from each of the batteries 24. External devices of vehicle 10 can be connected to connector 45.

[0020] ECU 50 includes a control unit 51, a processing unit 52, a storage unit 53, and a communication unit 54. The control unit 51 controls the drive unit 40 to control the charging and discharging of the battery 24.

[0021] Processing device 52 includes a memory and a processor (neither shown). The memory includes read-only memory (ROM) and random access memory (RAM). The processor is, for example, a central processing unit (CPU) and executes various algorithms according to a program stored in the ROM. Processing device 52 calculates the state of charge (SOC) of battery 24, for example, based on voltage VB, current IB, and temperature TB.

[0022] Storage device 53 stores first historical information 55 and second historical information 56. First historical information 55 indicates various process history items of battery 24 and includes void volume information, inspection result information, and elapsed time information. Void volume information indicates the volume of voids within battery casing 26. The void volume is defined by subtracting the total volume of the electrodes and electrolyte solution of each battery 24 from the volume of battery casing 26. Inspection result information indicates the results of an airtightness inspection performed on battery 24. Elapsed time information indicates the time elapsed since each battery 24 began use in vehicle 10 (delivery of vehicle 10 to the user). The elapsed time is defined, for example, in months or years.

[0023] The second historical information 56 includes the history of voltage VB, current IB, temperature TB, and state of charge (SOC) of each of the batteries 24 installed in the vehicle 10 during a period (hereinafter also referred to as the "vehicle installation period"). The history of temperature TB includes the temperature frequency indicating the frequency (time) at which temperature TB has each temperature value. The history of SOC includes the SOC frequency indicating the frequency (time) at which SOC has each value. The communication device 54 is capable of transmitting the first historical information 55 and the second historical information 56 to an external server.

[0024] Terminal device 100 is a maintenance terminal for distributors, etc., and includes a communication device 102, a storage device 104, an input device 106, a display device 108, and a control device 110.

[0025] The communication device 102 obtains first historical information 55 and second historical information 56 from the storage device 53 of the vehicle 10 via a communication cable connected to the connector 45. In the case where multiple pieces of information are stored in an external server, the communication device 102 can obtain multiple pieces of information from the server via wired or wireless communication. The storage device 104 corresponds to an example of a "storage unit" according to this disclosure, and stores the obtained first historical information 55 and second historical information 56 as first historical information 202 and second historical information 205 as described below. Figure 2 ).

[0026] Input device 106 receives various user operations. Display device 108 displays various screen images. Control device 110 controls display device 108. Control device 110 includes a memory and a processor (neither shown). The memory includes ROM and RAM. The processor is, for example, a CPU, and executes various algorithmic processes according to the program stored in the ROM. Thus, control device 110 acts as a processing device that performs various processes.

[0027] After battery 24 has been used in vehicle 10, it can be removed from vehicle 10 at a dealership or similar location. Subsequently, if each of the batteries 24 is reusable, battery 24 can be reused for the desired application. Therefore, it is important to properly diagnose the reusability of battery 24.

[0028] During vehicle installation, the gas generated within battery 24 causes an increase in internal pressure, making it susceptible to damage to battery casing 26. This damage increases over time. The internal pressure varies depending on the elapsed time since battery 24 began use in vehicle 10 and generally increases over a long period. As more damage to battery casing 26 occurs due to internal pressure, it may fail due to fatigue, and battery casing 26 may rupture. Therefore, battery 24 may be difficult to reuse.

[0029] Accordingly, the terminal device 100 of the diagnostic system 1 according to this embodiment includes components that appropriately diagnose the reusability of the battery 24 and allow the battery 24 to be reused. A description of this point is given below.

[0030] Figure 2 This is a block diagram illustrating the data stored in the storage device 104 and the functional components of the control device 110. (Referring to...) Figure 2 At that time, the storage device 104 stores the first historical information 202, the second historical information 205, the mapping 210, 220, the mapping group 215, and the usage condition information 217.

[0031] The first historical information 202 and the second historical information 205 are the same as the first historical information 55 and the second historical information 56 stored in the storage device 53 of the ECU 50. The mappings 210, 220, mapping group 215 and usage condition information 217 will be described below.

[0032] The control device 110 includes an internal pressure change estimation unit 250, a damage calculation unit 255, a service life prediction unit 260, a diagnostic unit 265, a diagnostic result output unit 267, a mitigation period determination unit 270, and a command output unit 275 as its functional components. These functions are implemented when the processor of the control device 110 executes a program stored in ROM.

[0033] The internal pressure change estimation unit 250 estimates the internal pressure change of the battery 24 according to the first historical information 202 and the second historical information 205 as follows.

[0034] The internal pressure transition estimation unit 250 estimates, for example, the gas generation rate of the battery 24 at each moment during the vehicle installation period based on the SOC and temperature TB indicated by the second historical information 205. The internal pressure transition estimation unit 250 estimates the rate of increase of the internal pressure of the battery 24 at each moment based on the estimated gas generation rate and the void volume information of the first historical information 202. Therefore, the internal pressure transition estimation unit 250 estimates the amount of internal pressure increase at each moment based on the rate of increase of internal pressure and the elapsed time at each moment. For example, the amount of increase is estimated 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 internal pressure transition of the battery 24 during the vehicle installation period based on a predetermined initial internal pressure reference value and the amount of internal pressure increase. The internal pressure transition estimation unit 250 can estimate the total amount of internal pressure increase during the vehicle installation period (hereinafter also referred to as "total internal pressure increase") based on the estimation results. The total internal pressure increase corresponds to the increase in internal pressure P from the start of use of each of the batteries 24 in the vehicle 10 to the end of use of the battery 24.

[0035] The internal pressure change estimation unit 250 can estimate the amount of gas transferred by the battery casing 26 based on the historical temperature TB, and thereby estimate the rate of decrease in internal pressure. In this case, the internal pressure change estimation unit 250 estimates the amount of decrease in internal pressure according to the rate of decrease in internal pressure and the elapsed time. For example, the amount of decrease is estimated by multiplying the rate of decrease in internal pressure by the elapsed time. Then, the internal pressure change estimation unit 250 can calculate the difference between the amount of increase and decrease in internal pressure estimated as described above, and thereby estimate the total increase in internal pressure.

[0036] The internal pressure change estimation unit 250 can correct the internal pressure change estimation result according to the inspection result information in the first historical information 202. Alternatively, the internal pressure change estimation unit 250 can estimate the change in the amount of gas transmitted through the sealing member according to the historical temperature TB, and correct the internal pressure change estimation result according to the estimation result.

[0037] After each of the batteries 24 has been used in the vehicle 10, the damage calculation unit 255 calculates the amount of damage to the battery casing 26 caused by the internal pressure of the battery 24 during the vehicle installation period (hereinafter also referred to as "damage amount"). As described below, the damage calculation unit 255 calculates the damage amount using the mapping 210 based on the estimation result of the internal pressure change estimation unit 250.

[0038] Figure 3 This is a diagram illustrating the data structure of mapping 210. (When referring to...) Figure 3 The mapping 210 indicates the relationship between the internal pressure P of the battery 24, the duration CT of the internal pressure P, and the increase in damage amount over the duration CT. For example, if the internal pressure P is P1 and lasts for CT1, the damage amount calculation unit 255 calculates the increase in damage amount as d11. Then, if the internal pressure P is P2 (>P1) and lasts for CT2, the damage amount calculation unit 255 calculates the increase in damage amount as d22. The damage amount calculation unit 255 integrates the increases calculated in this way and thereby calculates the damage amount during the vehicle installation period. The initial value of the damage amount is, for example, zero. This mapping 210 is appropriately defined in advance in evaluation tests or the like. It is worth noting that the lower the internal pressure P, the smaller the increase in damage amount per unit time (increase rate). In other words, the lower the internal pressure P, the less likely the battery casing 26 is to be damaged by the internal pressure P.

[0039] When referring again Figure 2The lifespan prediction unit 260 predicts the length of the lifespan of the battery 24 during repeated use based on the damage amount and usage condition information 217 calculated as described above. This period is also referred to as the "reusability lifespan". The usage condition information 217 indicates the usage conditions imposed on each of the batteries 24 when the battery 24 is reused after its use in the vehicle 10 has ended. The usage condition information 217 is appropriately defined in advance by user operation performed by the input device 106. The usage condition information 217 includes, for example, predicted values ​​of the maximum SOC and maximum temperature of the battery 24 during repeated use, but is not limited to these. The predicted values ​​may also be replaced by set values ​​or allowable values ​​of the maximum SOC and maximum temperature. As described below, the damage amount calculation unit 255 uses the mapping group 215 to predict the length of the reusability lifespan.

[0040] Figure 4 This is a diagram illustrating the data structures of mapping group 215 and mapping 220. (Refer to...) Figure 4 At that time, mapping group 215 includes mappings 216_1, 216_2, 216_3, ... Each mapping indicates the relationship between the predicted maximum SOC and maximum temperature of battery 24 during repeated use and the length of its repeated use life, for each of the damage quantities. The predicted maximum SOC and maximum temperature are appropriately defined in advance based on the application of battery 24 during repeated use.

[0041] For example, if the calculated damage amount is D3, the lifespan prediction unit 260 selects mapping 216_3 from mapping group 215. Then, the lifespan prediction unit 260 uses mapping 216_3 to predict the length of the reuse lifespan based on the predicted values ​​of the maximum SOC and the maximum temperature of the battery 24 during reuse. In one example, if the predicted values ​​of the maximum SOC and the maximum temperature are X1 and TM1 respectively, the lifespan prediction unit 260 uses mapping 216_3 to predict the length of the reuse lifespan to be LT11.

[0042] The lifespan prediction unit 260 predicts the length of the reusable lifespan based on the usage conditions of the battery 24 during repeated use and the degree of damage to the battery casing 26 caused by the internal pressure P. Therefore, the length of the reusable lifespan can be accurately predicted.

[0043] When referring again Figure 2When the battery is reused, the diagnostic unit 265 switches its processing based on whether the length of the reuse life predicted by the lifespan prediction unit 260 is greater than or equal to the target length of the reuse life. The target length is pre-defined appropriately based on the application of the battery 24 during reuse. If the predicted reuse life is greater than or equal to the target length, the diagnostic unit 265 diagnoses the battery 24 as reusable. Conversely, if the predicted reuse life is less than the target length, the diagnostic unit 265 diagnoses the battery 24 as difficult to reuse. As described above, the diagnostic unit 265 can appropriately diagnose the reusability of the battery 24 based on the predicted reuse life.

[0044] When battery 24 is diagnosed as reusable, diagnostic result output unit 267 generates a command for display device 108 to output (display) the diagnostic result. The diagnostic result is thus displayed on display device 108 and the user is notified. Therefore, battery 24 can be reused for desired applications. For example, reusable battery 24 is incorporated into reusable products and sold with those products.

[0045] Conversely, if battery 24 is diagnosed as difficult to reuse, the length of its reuse life is insufficient, and therefore it is unnecessary to reuse battery 24 as described above. Then, even in this case, predetermined internal pressure relief measures are taken to allow relief of internal pressure P and to allow for an extension of the reuse life. Internal pressure relief measures are measures taken to store battery 24 for more than a predetermined period under conditions suitable for relieving (reducing) internal pressure P. Details of these conditions will be described in detail below. This predetermined period will also be referred to as the "relief period." The advantages of the internal pressure relief measures will be described below.

[0046] Figure 5 This is a diagram illustrating an example of the changes in internal pressure P and damage amount in the embodiment and its comparative example. The embodiment assumes that battery 24 is reused after being removed from vehicle 10 and internal pressure relief measures are taken. The comparative example assumes that battery 24 is reused immediately after being removed from vehicle 10 without internal pressure relief measures being taken.

[0047] When reference Figure 5 In this context, lines 310 and 315 represent the changes in internal pressure P and damage amount D in the embodiments, respectively. Lines 320 and 325 represent the changes in internal pressure P and damage amount D in the comparative examples, respectively.

[0048] Period T1 corresponds to the vehicle installation period and is defined as the period from time t0 to time t1. At time t0, the use of each of the batteries 24 in the vehicle 10 begins. At time t1, the use of the batteries 24 in the vehicle 10 ends and the batteries 24 are removed from the vehicle 10. During period T1, there is no difference in the internal pressure P and the damage amount D between the embodiment and the comparative example. For example, in either the embodiment or the comparative example, the internal pressure P is P1 and the damage amount D is D1 at time t1.

[0049] In the comparative example, after each of the batteries 24 is removed from the vehicle 10, the batteries 24 are immediately reused in period T2a. Period T2a is the period from time t1 to time t2a. As described above, the higher the internal pressure P, the higher the rate of increase in the damage amount D. The internal pressure P (P1) at time t1 is relatively high (line 320). Therefore, the damage amount D is prone to increase in period T2a and reaches the limit damage amount LM at time t2a (line 325). Therefore, the length of the reuse service life in the comparative example is only L2a.

[0050] Conversely, in this embodiment, internal pressure relief measures are implemented during period Ta. Thereafter, each of the batteries 24 is reused during period T2. Period Ta is the period from time t1 to time ta, and corresponds to the relief period described above. Period T2 is the period from time ta to time t2. The internal pressure relief measures alleviate the internal pressure P, reducing it from P1 to Pa. Since the internal pressure P (Pa) at time ta is relatively low (line 310), the rate of increase of damage D during period T2 is low (line 315). In other words, the damage D is less likely to increase during the reuse of the battery 24 compared to the comparative example. Therefore, the length of the reusable lifespan is L2 (>L2a). It is assumed that L2 is greater than the target length of the reusable lifespan.

[0051] As described above, this embodiment can extend the length of the reuse life through internal stress relief measures, and make the length of the reuse life greater than or equal to the target length. Therefore, even if the length of the reuse life predicted by the life prediction unit 260 is less than the target length, the remaining value of the battery 24 can be restored through internal stress relief measures, and the battery 24 can be reused.

[0052] Refer again Figure 4 Mapping 220 indicates the relationship between the damage amount D and the total increase in internal pressure, and the length of the mitigation period. The length of the mitigation period in Mapping 220 is defined as the length of the period during which the internal pressure P is relieved so that the length of the reuse service life is greater than or equal to the target length. It is worth noting that... Figure 4The term "impossible" means that, despite internal pressure mitigation measures, the length of the reuse service life cannot reach the target length based on certain combinations of damage amount D and total internal pressure increase. In other words, "impossible" indicates that the length of the mitigation period cannot be determined for the corresponding combination of damage amount D and total internal pressure increase. Mapping 220 is appropriately defined in advance by means of experimentation, etc.

[0053] When referring again Figure 2 The mitigation period determination unit 270 determines the length of the mitigation period using mapping 220 based on the total increase in internal pressure and the damage amount D after the battery 24 has been used in the vehicle 10. For example, if the total increase in internal pressure is ΔP1 and the damage amount D is D1, the mitigation period determination unit 270 determines the length of the mitigation period to be LN1 (see reference). Figure 4 Furthermore, if the length of the service life corresponding to the total increase in internal pressure and the amount of damage D in the mapping 220 is "impossible", the mitigation period determination unit 270 determines that the length of the mitigation period cannot be determined.

[0054] Mapping 220 can be defined for each process history item indicated by first history information 202 or for each usage condition indicated by usage condition information 217. Therefore, the length of the mitigation period can be determined more appropriately based on the processing history of battery 24 or the usage conditions of battery 24 during repeated use.

[0055] If the predicted reuse life is less than the target life and the length of the mitigation period can be determined, the command output unit 275 outputs a command to the user of the instruction diagnostic system 1 to take internal stress relief measures. The user is, for example, a technician at a dealership. This command is output to, for example, cause the display device 108 to display a screen indicating the instruction to take internal stress relief measures. Such a screen is thus displayed on the display device 108 and thus prompts the user to take internal stress relief measures. Therefore, the reuse life can be made greater than or equal to the target life, such as... Figure 5 As shown. When the length of the remission period as described above can be determined, the diagnostic unit 265 diagnoses the battery 24 as reusable. Conversely, when the length of the remission period cannot be determined, the diagnostic unit 265 diagnoses the battery 24 as difficult to reuse.

[0056] The internal pressure relief measures will be described in detail below. These measures correspond to actions taken when the battery 24 is stored beyond the relief period under at least one of the first, second, and third conditions described below. The first condition is that the temperature around the battery 24 is below a reference temperature, such as zero degrees Celsius. The second condition is that the pressure around the battery 24 is below or equal to the internal pressure P of the battery 24 after its use in the vehicle 10 (i.e., after the vehicle installation period). The third condition is that the space around the battery 24 is filled with a gas different from the gas inside the battery casing 26 (e.g., nitrogen).

[0057] Under the first condition, gas generation reaction and electrode degradation in battery 24 are suppressed. The rate of increase in internal pressure P is thus reduced. Furthermore, even if internal pressure P increases, the damage amount D is less likely to increase due to the low temperature under the first condition. Under the second condition, more of the gas generated in each of batteries 24 is transported to the outside of battery casing 26. Due to gas venting, internal pressure P is thus more easily reduced. Under the third condition, due to the difference between the partial pressure of the gas (e.g., carbon dioxide gas) inside battery casing 26 and the gas pressure in the adjacent space, which is different from the gas inside battery casing 26, the gas inside battery casing 26 can be transported to the outside. As described above, battery 24 is stored under at least one of the first to third conditions. This alleviates internal pressure P and allows for a lower rate of increase in damage amount D. As a result, the length of the reuse service life can be appropriately extended and battery 24 can be reused.

[0058] Figure 6 This is a flowchart illustrating the processing procedure performed by the terminal device 100 in this embodiment. The flowchart begins when the terminal device 100 is connected to the connector 45 via a communication cable. Before the flowchart begins, the battery 24 may have been removed from the vehicle 10, or the battery 24 in the power storage device 20 may still be installed in the vehicle 10.

[0059] When reference Figure 6At this time, terminal device 100 obtains first historical information 55 from vehicle 10 and stores the first historical information 55 in storage device 104 as first historical information 202 (S10). Terminal device 100 obtains second historical information 56 from vehicle 10 and stores the second historical information 56 in storage device 104 as second historical information 205 (S15). Terminal device 100 estimates the change in internal pressure P of each of the batteries 24 during the vehicle installation period according to the first historical information 202 and the second historical information 205 (S20). Terminal device 100 calculates the damage amount D using mapping 210 according to the estimation results in S20 (S25). Terminal device 100 receives user operation input specifying usage condition information 217 indicating the usage conditions of battery 24 during repeated use (S30). In this example, usage condition information 217 includes predicted values ​​of maximum SOC and maximum temperature. Terminal device 100 uses mapping group 215 to predict the reuse service life based on usage condition information 217 and damage amount D (S35).

[0060] Terminal device 100 switches processing based on whether the predicted reuse life is greater than or equal to the target life (S40). If the predicted reuse life is greater than or equal to the target life ("Yes" in S40), terminal device 100 diagnoses battery 24 as reusable (S42). After S42, terminal device 100 displays a screen on display device 108 indicating the diagnostic results of S42 and ends processing. If the predicted reuse life is less than the target life ("No" in S40), terminal device 100 uses mapping 220 to switch processing based on whether the length of the mitigation period can be determined (S45).

[0061] If the length of the relief period cannot be determined (No in S45), the terminal device 100 diagnoses the battery 24 as unusable (S47). After S47, the terminal device 100 displays a screen on the display device 108 indicating the diagnostic results of S47 and ends the process. Conversely, if the length of the relief period can be determined (Yes in S45), the terminal device 100 determines the length of the reusable service life corresponding to the total increase in internal pressure and the damage amount D (S50). Then, the terminal device 100 diagnoses the battery 24 as reusable (S52). Subsequently, the terminal device 100 outputs a command to the display device 108 instructing the user to take internal pressure relief measures (S55) and displays a screen on the display device 108 instructing the user to take internal pressure relief measures.

[0062] As described above, according to this embodiment, the length of the reusable lifespan is accurately predicted based on the damage amount D caused by the internal pressure P. Therefore, the reusability of battery 24 can be appropriately diagnosed. Furthermore, if the predicted reusable lifespan is less than the target length, the user is prompted to take internal pressure relief measures. Therefore, the length of the reusable lifespan can be appropriately extended, making it greater than or equal to the target length. Thus, the remaining value of battery 24 can be restored, allowing battery 24 to be reused. Other modification examples

[0063] Terminal device 100 can calculate internal pressure P and damage amount D according to first historical information 55 and second historical information 56 in storage device 53 of ECU 50. In this case, storage devices 53 and 104 each correspond to an example of a "storage unit" according to this disclosure.

[0064] The embodiments disclosed herein should be understood as illustrative in all respects and not as limiting. The scope of the invention is defined by the claims rather than the description. The scope of the invention is intended to include equivalents of the claims and all modifications within the scope of the claims.

Claims

1. A diagnostic system for diagnosing the reusability of a battery, the diagnostic system comprising: A storage unit configured to store historical information indicating the battery's voltage, current, and temperature during the period the battery was installed in the vehicle; An estimation unit is configured to estimate changes in the internal pressure of the battery based on the historical information, the internal pressure varying according to the time elapsed since the battery began to be used in the vehicle; A calculation unit is configured to calculate, based on the estimation results of the estimation unit, the amount of damage to the battery casing caused by the internal pressure during the period after the battery has been used in the vehicle. as well as The prediction unit is configured to predict the length of the battery's lifespan during repeated use based on usage condition information and the amount of damage, wherein the usage condition information indicates the usage conditions applied to the battery when it is reused after the end of the initial use.

2. The diagnostic system according to claim 1, wherein The usage condition information includes predicted values ​​for the battery's maximum SOC and highest temperature during repeated use. The storage unit also stores a plurality of predefined first relationships, and each of the plurality of first relationships indicates, for each damage amount, a relationship between the predicted values ​​of the maximum SOC and the maximum temperature and the length of the service life, and The prediction unit Select the relationship corresponding to the damage amount from the first relationship, and The length of the service life is predicted using the selected relationship based on the predicted values ​​of maximum SOC and highest temperature.

3. The diagnostic system according to claim 1 or 2 further includes a command output unit configured to output a command to take predetermined measures to alleviate the internal pressure when the predicted service life is less than the target service life predicted by the prediction unit.

4. The diagnostic system according to claim 3, wherein The predetermined measures include storing the battery beyond a predetermined mitigation period under at least one of the first, second, and third conditions. The length of the relief period is determined to be the length of the period during which the internal pressure is relieved so that the length of the durability period is greater than or equal to the target length. The first condition is that the temperature around the battery is lower than a reference temperature. The second condition is that the pressure around the battery is lower than or equal to the internal pressure of the battery after use in the vehicle. The third condition is that the space surrounding the battery is filled with a gas different from the gas inside the casing.

5. The diagnostic system according to claim 4, wherein The estimation unit estimates the increase in internal pressure from the start of use to the end of use based on the estimation results of the transformation. The storage unit also stores a second relationship indicating the relationship between the amount of damage and the amount of increase and the length of the mitigation period, the relationship being predefined. The diagnostic system further includes a determination unit configured to determine the length of the remission period using the second relationship based on the increase and the damage amount.

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