vehicle

Abstract

To improve the accuracy of estimating the capacity retention rate of the vehicle's power storage system. [Solution] Vehicle 1 is equipped with a main battery 40, a PCU 80 and an MG 90, and a battery ECU 100. The battery ECU 100 calculates the amount of degradation due to energization and the amount of degradation due to standing still by performing first and second processes, and estimates the capacity retention rate according to the sum of these. Vehicle 1 is configured to be able to perform a function to energize the main battery 40 during the stationary period. The battery ECU 100 performs a first process using the amount of energized electricity during the driving period and the total amount of energized electricity over the period during which the function is performed during the stationary period. The execution time length, which indicates the elapsed time of the above execution period, is converted into an estimated time length required for the total amount of energized electricity to be supplied to the energy storage device during the driving period. The second process is performed using the elapsed time length of the vehicle standing still during the stationary period and the difference in time length obtained by subtracting the estimated time length from the execution time length.

Description

[Technical Field]

[0001] This disclosure relates to vehicles. [Background technology]

[0002] Japanese Patent Publication No. 2019-53074 (Patent Document 1) discloses a degradation estimation device capable of accurately estimating the degradation of an energy storage element. The degradation estimation device comprises an acquisition unit and an estimation unit. The acquisition unit acquires time-series data of the State of Charge (SOC) of the energy storage element. The estimation unit uses a coefficient based on the magnitude of the fluctuation of SOC in the time-series data acquired by the acquisition unit to calculate an energized degradation value indicating the degradation of the energy storage element due to energization, and estimates the degradation of the energy storage element based on the sum of the calculated energized degradation value and an unenhanced degradation value indicating the degradation of the energy storage element without energization. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2019-53074 [Overview of the project] [Problems that the invention aims to solve]

[0004] Vehicles equipped with energy storage devices for propulsion are becoming increasingly common. When estimating the capacity retention rate of such energy storage devices, based on the sum of the degradation caused by energization and the degradation caused by non-energization, there is a need to estimate the capacity retention rate with high accuracy.

[0005] This disclosure has been made to solve the above-mentioned problems, and its purpose is to improve the accuracy of estimating the capacity maintenance rate of the energy storage device for vehicle operation. [Means for solving the problem]

[0006] The vehicle of this disclosure comprises a power storage device, a drive device, and a processing device. The drive device generates the driving force for the vehicle using the power of the power storage device. The processing device calculates a first degradation amount of the power storage device by performing a first process using the amount of electricity supplied to the power storage device, and calculates a second degradation amount of the power storage device by performing a second process using the elapsed time during the non-operation period of the drive device, and estimates the capacity maintenance rate of the power storage device according to the sum of the first degradation amount and the second degradation amount. The vehicle is configured to be able to perform a function to energize the power storage device during the non-operation period. The processing device performs a first process using the amount of electricity supplied during the operation period of the drive device and the total amount of electricity supplied over the period during which the function is performed during the non-operation period, converts the execution time length, which indicates the elapsed time during the execution period, into an estimated time length required for the total amount of electricity to be supplied to the power storage device during the operation period, and performs a second process using the elapsed time length of the vehicle's idle period during the non-operation period and the difference time length obtained by subtracting the estimated time length from the execution time length.

[0007] With the above configuration, the total amount of electricity supplied to the energy storage device over the entire period, along with the amount of electricity supplied to the drive device during its operation, is reflected in the first degradation amount. Furthermore, the difference in time length, along with the elapsed time during the idle period, is reflected in the second degradation amount. As a result, the sum of the first and second degradation amounts accurately represents the degree of degradation of the energy storage device. Consequently, the capacity retention rate can be estimated accurately according to this sum. Therefore, the accuracy of estimating the capacity retention rate of the energy storage device can be improved.

[0008] In one aspect, the vehicle further includes a storage unit. The storage unit stores a first relationship indicating the relationship between the temperature of the power storage device and the energization deterioration rate of the power storage device, and a second relationship indicating the relationship between the temperature and SOC of the power storage device and the storage deterioration rate of the power storage device. The first process includes a process of calculating, for each temperature of the power storage device, a value obtained by multiplying the square root of the energized electric quantity by the energization deterioration rate using the first relationship, and summing the calculated values for all temperatures to calculate a first deterioration amount. The second process includes a process of calculating, for each temperature and SOC of the power storage device, a value obtained by multiplying the square root of the elapsed time length in the non-operating period by the storage deterioration rate using the second relationship, and summing the calculated values for all temperatures and all SOCs to calculate a second deterioration amount.

[0009] In one aspect, the processing device estimates the capacity retention rate using the square root of the sum as the degree of deterioration of the power storage device.

[0010] In one aspect, the vehicle further includes an auxiliary battery and a charging device. The charging device charges the auxiliary battery using discharge power from the power storage device. The function includes a function of charging the auxiliary battery by the charging device.

[0011] In one aspect, the vehicle further includes a power supply port and a power supply device. The power supply device supplies power to the outside of the vehicle through the power supply port using discharge power from the power storage device. The function includes a function of supplying power to the outside by the power supply device. [Effects of the Invention]

[0012] According to the present disclosure, it is possible to improve the estimation accuracy of the capacity retention rate of the power storage device for vehicle travel. [Brief Description of the Drawings]

[0013] [Figure 1] It is a block diagram showing an example of the overall configuration of a vehicle according to the present embodiment. [Figure 2] It is a diagram for explaining a map stored in a memory of a battery ECU (Electronic Control Unit). [Figure 3] This diagram illustrates how the main battery is used during a 24-hour period of stationary operation. [Figure 4] This flowchart shows an example of the estimation process procedure in this embodiment. [Figure 5] This figure shows a simulated driving pattern used to calculate the electrical degradation coefficient aj. [Figure 6] This diagram illustrates a method for calculating the deterioration coefficient bjk. [Modes for carrying out the invention]

[0014] 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 of the embodiments and its modifications may be combined with one another as appropriate.

[0015] Figure 1 is a block diagram showing an example of the overall configuration of a vehicle according to this embodiment. Referring to Figure 1, Vehicle 1 is an electric vehicle (BEV: Battery Electric Vehicle).

[0016] Vehicle 1 includes an inlet 10, an AC / DC converter 20, a relay 30, a main battery 40, a monitoring unit 50, a DC / DC converter 60, an auxiliary battery 70, a PCU (Power Control Unit) 80, an MG (Motor Generator) 90, a battery ECU 100, and a vehicle ECU 110.

[0017] The inlet 10 is configured to allow insertion of a charging connector provided at the end of the charging cable 901. The inlet 10 corresponds to an example of a "power supply port" in this disclosure.

[0018] The AC / DC converter 20 converts AC power supplied from an external power source (not shown) installed outside the vehicle 1 via the charging cable 901 and inlet 10 into DC power, and uses that DC power to charge the main battery 40 (external charging). The AC / DC converter 20 can also convert the DC power, which is the discharge power from the main battery 40, into AC power, and use that AC power to supply power to an external load 902 via the inlet 10 (external power supply). The external load 902 is, for example, a house, but may also be various electrical equipment. The AC / DC converter 20 corresponds to an example of a "power supply device" in this disclosure.

[0019] Relay 30 is electrically connected to the power line connecting the AC / DC converter 20 and the main battery 40. Relay 30 is opened and closed according to control commands from the vehicle ECU 110.

[0020] The main battery 40 is a battery pack containing multiple cells. Each cell is a secondary battery such as a lithium-ion battery or a nickel-metal hydride battery. The main battery 40 stores the power for the vehicle 1 to run. The main battery 40 corresponds to an example of the “energy storage device” in this disclosure.

[0021] The monitoring unit 50 includes a voltage sensor 51, a current sensor 52, and a temperature sensor 53. The voltage sensor 51, current sensor 52, and temperature sensor 53 output the detected values ​​of the voltage V, current I, and temperature T of the main battery 40 to the battery ECU 100, respectively.

[0022] The DC / DC converter 60 charges the auxiliary battery 70 using the discharge power from the main battery 40 according to control commands from the vehicle ECU 110 (auxiliary battery discharging). The DC / DC converter 60 corresponds to an example of a "charging device" in this disclosure. The auxiliary battery 70 stores power for driving the auxiliary equipment (not shown) of the vehicle 1.

[0023] The PCU80 drives the MG90 using power from the main battery 40 in accordance with control commands from the vehicle ECU110. The MG90 rotates the drive shaft of the vehicle 1 to generate the driving force for the vehicle 1. The operating and non-operating periods of the PCU80 and MG90 correspond to the driving and stationary periods of the vehicle 1, respectively. The PCU80 and MG90 correspond to examples of the “drive system” of this disclosure.

[0024] The battery ECU 100 includes a processor 101 and a memory 102. The processor 101 is, for example, a CPU (Central Processing Unit). The memory 102 includes ROM (Read Only Memory) and RAM (Random Access Memory). The ROM stores various maps and programs.

[0025] The battery ECU 100 manages the main battery 40 according to the signals input from each sensor of the monitoring unit 50 and the maps and programs stored in the memory 102. For example, the battery ECU 100 sequentially calculates the state of charge (SOC) of the main battery 40 according to the detected values ​​of voltage V, current I, and temperature T, and stores it in the memory 102. As a result, a history of these detected values ​​is generated in the memory 102.

[0026] The vehicle ECU 110, like the battery ECU 100, includes a processor and memory (neither of which are shown). The vehicle ECU 110 controls various devices such as the AC / DC converter 20, relay 30, DC / DC converter 60, and PCU 80 so that the vehicle 1 reaches a desired state, according to the input signals from each sensor installed in the vehicle 1 and the maps and programs stored in the memory.

[0027] The vehicle ECU 110 controls the PCU 80, for example, to enable the MG 90 to generate driving force, and controls various devices to perform predetermined functions such as energizing the main battery 40 when the vehicle 1 is stopped. One example of a predetermined function is the charging function of the main battery 40 by the AC / DC converter 20 (external charging), the power supply function of the AC / DC converter 20 from the main battery 40 to an external load 902 (external power supply), or the charging function of the auxiliary battery 70 from the main battery 40 by the DC / DC converter 60 (auxiliary battery drain).

[0028] The following describes the processing performed by the battery ECU 100 in detail. The battery ECU 100 performs an "estimation process" to estimate the capacity retention rate of the main battery 40. The capacity retention rate refers to the ratio of the current full charge capacity to the initial full charge capacity of the main battery 40.

[0029] The battery ECU 100 is configured to execute two logics in the estimation process: an energization degradation logic and a neglect degradation logic. These logics correspond to the "first process" and the "second process" in this disclosure, respectively.

[0030] The power supply degradation logic is a process that calculates the amount of degradation of the main battery 40 due to power supply, using the amount of power supplied to the main battery 40 (for example, the amount of power supplied during the operation period of vehicle 1) [unit: Ah]. The amount of power supplied to the main battery 40 is also simply referred to as "power supply". The battery ECU 100 calculates the power supply amount at predetermined time intervals (for example, 1 second) according to the detected value of current I, and sequentially stores this power supply amount in the memory 102 in association with the detected value of temperature T at that time interval. The amount of degradation due to power supply depends on the temperature of the main battery 40. The higher the temperature of the main battery 40, the greater this degradation.

[0031] The battery ECU 100 calculates the amount of current supplied to the main battery 40 for each temperature T of the main battery 40 during the period for which the amount of current supply degradation is to be calculated (for example, the driving period). The battery ECU 100 calculates the amount of degradation of the main battery 40 due to current supply for each temperature T during the above period, according to the amount of current supplied. The battery ECU 100 calculates the amount of current supply degradation d1 by summing up the calculated degradation amounts for all temperatures.

[0032] More specifically, the battery ECU100 calculates the amount of current degradation d1 according to the following formula (1) in its current degradation logic.

[0033]

number

[0034] In equation (1), j is a natural number (j=1,2,···J) used to distinguish the temperature (battery temperature) of the main battery 40. Current flow rate Ah j This represents the amount of current supplied to the main battery 40 at the corresponding battery temperature. Current degradation coefficient a j This is the amount of charge in Ah at the corresponding battery temperature. j This represents the current-conducting degradation rate, which is the amount of degradation of the main battery 40 per square root of the current-conducting degradation coefficient a. j This is determined through prior evaluation tests, etc., assuming that the power necessary to realize the driving simulation patterns described later is supplied from the main battery 40 to the PCU 80 and MG90, and that the vehicle 1 is driven.

[0035] The idle degradation logic is a process that calculates the amount of degradation of the main battery 40 over time using the elapsed time during the vehicle 1's stationary period (for example, the elapsed time during the vehicle 1's idle period). This amount of degradation is also referred to as the "amount of degradation due to idle." The vehicle 1's idle period is a part of the stationary period, and is typically the period when the vehicle 1's running system is in the ReadyOFF state and the main battery 40 is not energized. The ReadyOFF state is a state in which the main battery 40 is electrically isolated from other equipment of the vehicle 1, such as by opening a System Main Relay (SMR) (not shown) installed in the main battery 40.

[0036] The stationary degradation amount depends on the temperature and SOC of the main battery 40. The higher the temperature of the main battery 40, the larger the stationary degradation amount, and the higher the SOC of the main battery 40, the larger the stationary degradation amount. Therefore, the battery ECU 100 calculates, for each combination of the temperature and SOC of the main battery 40, the temporal degradation amount of the main battery 40 according to the length of elapsed time during the stop period, and sums up the calculated degradation amounts for all combinations (temperature and SOC) to calculate the stationary degradation amount d2. The above elapsed time length is stored in the memory 102 in association with each of the above combinations.

[0037] More specifically, in the stationary degradation logic, the battery ECU 100 calculates the stationary degradation amount d2 according to the following formula (2).

[0038]

Formula

[0039] In formula (2), j is a natural number (j=1,2,···J) for distinguishing the battery temperature. k is a natural number (k=1,2,···K) for distinguishing the SOC. The time length t jk is the time length of the elapsed time at the corresponding battery temperature and SOC within the period that is the calculation target of the stationary degradation amount d2 (for example, the stationary period). In this example, the time length t jk is expressed in units of days, but may be expressed in units of 1 hour [h], for example. The stationary degradation coefficient b jk is the stationary degradation rate representing the degradation amount of the main battery 40 per square root of the time length t at the corresponding battery temperature and SOC. jk

[0040] Figure 2 is a diagram for explaining a map stored in the memory 102 of the battery ECU 100. Referring to Figure 2, the map 105 shows the correspondence relationship between the temperature T of the main battery 40 and the energization degradation coefficient a j . j is determined in advance by an evaluation test or the like for every 1°C within the temperature range of the temperature T from -45°C to 65°C.

[0041] ​ Map 106 shows temperature T and SOC and storage degradation coefficient b. jk The relationship between the two is shown. Deterioration coefficient b jk The current degradation coefficient a is determined by prior evaluation tests, etc., at 1°C intervals within the temperature range from -45°C to 65°C, and at 10% to 20% SOC intervals within the SOC range from 0% to 100%. In this example, J=111 and K=7. j and the degradation coefficient b jk The detailed calculation method will be explained later with reference to Figures 5 and 6.

[0042] The battery ECU 100 uses map 105 to determine the current degradation coefficient a corresponding to temperature T. j Similarly, the battery ECU 100 uses map 106 to determine the storage degradation coefficient b corresponding to the combination of temperature T and SOC. jk To decide.

[0043] Battery ECU100 has an electrical degradation coefficient a j Using this, calculate the current degradation amount d1 according to formula (1), and the degradation coefficient b due to neglect. jk The amount of degradation due to neglect, d2, is calculated using formula (2). Then, the battery ECU 100 estimates the capacity retention rate CR of the main battery 40 according to the sum D of the energization degradation amount d1 and the neglect degradation amount d2. Specifically, the battery ECU 100 estimates the capacity retention rate CR [%] of the main battery 40 by subtracting the square root of the sum D from 100, assuming that the square root of the sum D represents the degree of degradation of the main battery 40 (degree of decrease in full charge capacity) (see formula (3) below).

[0044] CR = 100 - √D ... (3) When estimating the capacity retention rate (CR) using formulas (1) to (3), the accuracy of the CR estimation tends to be low in the comparative example described below. This point will be explained below.

[0045] Figure 3 is a diagram showing how the main battery 40 is used during a 24-hour period of inactivity. Referring to Figure 3, in both the comparative example and this embodiment, the amount of current degradation d1 is calculated according to formula (1) using the amount of current supplied during the running period, the amount of degradation due to inactivity d2 is calculated according to formula (2) using the elapsed time during the inactivity period, and the capacity retention rate CR is estimated according to formula (3) using the sum of these degradation amounts D.

[0046] This example describes a scenario where a predetermined function is performed for 8 hours during a given day, while vehicle 1 is left idle for 16 hours. The elapsed time of the predetermined function execution period (TPF) and the idle period (TPU) of vehicle 1 are also represented as the execution time length (TLF) and idle time length (TLU), respectively. Both of these periods are part of the non-operation period of PCU 80 and MG 90. The execution time length (TLF) and idle time length (TLU) are stored in the memory 102 of the battery ECU 100.

[0047] During the TPF execution period, the value of current I (battery current value) is significantly smaller (in one example, by one or two orders of magnitude) than that during the running period. For example, while the guideline battery current value during the running period (guideline running current value) is 50A, the guideline battery current value when external power is supplied is 5A, and the guideline battery current value when auxiliary power is supplied is 0.2A. The guideline running current value is determined in advance as appropriate by prior evaluation tests, for example, as the average of the battery current values ​​during the running period. In this example, auxiliary power supply is performed as a predetermined function, and the total amount of current supplied to the main battery 40 over the TPF execution period is 1.6Ah (=0.2A × 8h). This total amount is also called the "total amount of current supplied during the predetermined period".

[0048] The following describes the method for estimating the capacity retention rate CR in the comparative example. As mentioned above, the specified function is a low-rate current flow function, while formula (1) assumes high-rate current flow during the running period. Applying the current flow amount and temperature T during the TPF directly to formula (1) in order to estimate the capacity retention rate CR considering the degradation of the main battery 40 during the TPF would lead to a decrease in the accuracy of the capacity retention rate CR estimation. In the comparative example, the current flow degradation amount d1 is calculated using formula (1) assuming that the total current flow during the specified period was performed at a high rate, and the capacity retention rate CR is estimated according to the calculation result. For example, the current flow amount Ah corresponding to the average battery temperature during the TPF a (Current flow rate Ah when j=a) j ) and the total amount of current supplied during the specified period is the amount of current supplied Ah a As an alternative, the amount of current degradation d1 is calculated using formula (1) (Note that for values ​​of j other than a, the total amount of current supplied during the specified period is not considered, and the amount of current supplied during the running period Ah is not considered). j The current degradation amount d1 is calculated accordingly. However, in the comparative example, the capacity retention rate CR may be estimated higher than the actual value, resulting in an inaccurate estimation.

[0049] Therefore, the battery ECU 100 of vehicle 1 according to the embodiment has a configuration for more accurately estimating the capacity retention rate CR. Specifically, the battery ECU 100, like the comparative example, measures the amount of current supplied Ah during the driving period. j The current degradation amount d1 is calculated using the total current supplied during a predetermined period, and the idle time length TLU and the difference time length TLb (described later) are used to calculate the idle degradation amount d2. The method by which the battery ECU 100 calculates the idle degradation amount d2 is explained in detail below.

[0050] First, the battery ECU 100 converts the running time length TLF into a guideline time length TLa. The guideline time length TLa is an estimate of the time required for the total amount of current supplied to the main battery 40 during a predetermined period of operation. The battery ECU 100 calculates the guideline time length TLa by dividing the total amount of current supplied during the predetermined period by the guideline running current value. In this example, the guideline time length TLa is 0.032 (=1.6 / 50) [days].

[0051] Next, the battery ECU 100 calculates the differential time length TLb by subtracting the target time length TLa from the execution time length TLF. In this example, the differential time length TLb is 7.97 (=8-0.032) [days].

[0052] Subsequently, the battery ECU100 operates for a period of time t jk The amount of degradation d2 is calculated according to formula (2) using the difference time length TLb. For example, the battery ECU 100 stores the time length t in memory 102 in association with a combination of temperature T, which is equal to the average value of temperature T during the execution period TPF, and SOC, which is equal to the average value of SOC during the execution period TPF. bc (Time length t in the case where j=b,k=c) jk ) and the sum of the difference time length TLb is time length t bc As an alternative, the amount of degradation d2 due to neglect is calculated according to formula (2) (Note that for j values ​​other than b, and k values ​​other than c, the difference time length TLb is not considered, and the time length t during the neglect period TPU is used). jk The amount of deterioration due to neglect, d2, is calculated accordingly.

[0053] After calculating the current degradation amount d1 and the residual degradation amount d2 as described above, the battery ECU100 estimates the capacity retention rate CR according to formula (3) using the sum D of these degradation amounts.

[0054] The comparative example corresponds to a case where, assuming that no degradation of the main battery 40 occurs during the differential time length TLb, the degree of degradation of the main battery 40 (square root of the sum D) is calculated according to equations (1) to (3) and the capacity retention rate CR is estimated. As a result, in the comparative example, the sum D is calculated to be smaller than the actual value, and the capacity retention rate CR is estimated to be higher than the actual value.

[0055] In contrast, according to the embodiment, the amount of current supplied during the driving period is Ah. j In addition, the total amount of current supplied during a predetermined period is reflected in the current degradation amount d1, while the time length of the standing time TLU t jkIn addition, the difference in time length TLb is reflected in the amount of degradation d2 due to neglect. As a result, the sum D is calculated to be somewhat larger than in the comparative example, and the square root of the sum D accurately represents the degree of degradation of the main battery 40. Consequently, the error between the estimated value and the actual value of the capacity retention rate CR is reduced. Therefore, the accuracy of estimating the capacity retention rate CR can be improved.

[0056] Figure 4 is a flowchart showing an example of the estimation process procedure in this embodiment. This flowchart is executed at predetermined control cycles (24 hours in this example). Hereafter, each step will be abbreviated as "S".

[0057] In S10, the battery ECU 100 determines whether a predetermined function has been performed in the most recent 24 hours (S10). The battery ECU 100 determines, for example, whether the length of the period during which the value of current I was greater than zero and less than the reference current value (5A in one example) is greater than or equal to a predetermined time. If the period is greater than or equal to the predetermined time, the period is considered to be the execution period TPF, and it is determined that the predetermined function has been performed. Otherwise, it is determined that the predetermined function has not been performed.

[0058] If a predetermined function is executed (YES in S10), the battery ECU 100 calculates the total amount of current supplied during the predetermined period according to the history of the detected value of current I (S12). The battery ECU 100 then stores the amount of current supplied during the driving period Ah in the memory 102. j Then, using the total amount of current supplied during the predetermined period, the current degradation amount d1 is calculated according to formula (1) using a current degradation logic (S14).

[0059] The battery ECU 100 converts the execution time length TLF into a target time length TLa by dividing the total amount of current supplied during a predetermined period by the target running current value (S16). The battery ECU 100 calculates the difference time length TLb by subtracting the target time length TLa from the execution time length TLF, and calculates the idle time length TLU (more specifically, the time length t of the idle period TLU). jk The amount of deterioration d2 due to neglect is calculated according to equation (2) using a neglect deterioration logic that utilizes ) and the difference time length TLb (S17).

[0060] If the specified function is not executed (NO in S10), the battery ECU 100 will determine the amount of charge supplied during the driving period in Ah. j The current degradation logic using the above method calculates the current degradation amount d1 according to formula (1) (S18). Next, the battery ECU 100 calculates the time length t of the idle period TLU. jk The amount of degradation due to neglect d2 is calculated according to formula (2) using the neglect degradation logic (S19). S18 and S19 correspond to the process in S14 and S17 where the total amount of current supplied during the predetermined period is zero, respectively.

[0061] The battery ECU100 estimates the capacity retention rate CR according to formula (3) using the sum D of the current degradation amount d1 and the degradation amount d2 due to standing (S20).

[0062] Figure 5 shows the current-conducting degradation coefficient a j This figure shows a simulated driving pattern (i.e., a current flow pattern for a battery of the same type as the main battery 40) for calculating the current flow rate. Figure 5(A) shows the change in the battery's current value (left column) and the change in the battery's State of Charge (SOC) in the simulated driving pattern for one cycle of the battery (right column). Current flow degradation coefficient a j To calculate this, an energization endurance test is conducted under constant ambient temperature conditions for the battery. Specifically, the battery is charged and discharged over numerous cycles in a simulated driving pattern where the current value and SOC change as shown in the diagram, at a constant ambient temperature.

[0063] Figure 5(B) shows the measurement results of the battery's capacity retention rate CR after the above-described energization endurance test. Generally, the decrease in the capacity retention rate CR due to energization is proportional to the square root of the amount of energization performed on the main battery 40. Therefore, as shown in Figure 5(B), if the amount of energization performed on the main battery 40 is plotted on the horizontal axis and the capacity retention rate CR of the main battery 40 is plotted on the vertical axis, the relationship between the capacity retention rate CR and the square root of the amount of energization is represented by a straight line. The slope of this straight line is the energy degradation coefficient a. j This corresponds to the current degradation coefficient a at 25°C. j The coefficient of degradation a at 40°C is 0.0005. jThe current degradation coefficient a at 60°C is 0.0007. j The value was 0.001.

[0064] Figure 6 shows the degradation coefficient b. jk This figure illustrates the calculation method. Generally, under conditions where the State of Charge (SOC) is constant, the decrease in the capacity retention rate (CR) over time is proportional to the square root of the elapsed time. Therefore, as shown in Figure 6, if the square root of the elapsed time (number of days) is plotted on the horizontal axis and the capacity retention rate (CR) on the vertical axis, the relationship between the capacity retention rate (CR) and the square root of the elapsed time is also represented by a straight line. The slope of this straight line is the coefficient of deterioration due to neglect b jk This corresponds to the degradation coefficient b at 25°C when SOC = 90%. jk The coefficient of deterioration b at 40°C is 0.006. jk The degradation coefficient b at 60°C is 0.009. jk The value was 0.01. Although not shown in the figure, a similar straight line can be obtained under conditions where the temperature is equal but the SOC is different.

[0065] As described above, in this embodiment, the amount of current supplied during the running period is Ah. j In addition, the total amount of current supplied during a predetermined period is reflected in the current degradation amount d1. Furthermore, the duration t of the idle period TPU jk In addition, the difference in time length TLb is reflected in the amount of degradation d2 due to neglect. As a result, the square root of the sum D accurately represents the degree of degradation of the main battery 40, reducing the error between the estimated value and the actual value of the capacity retention rate CR. Consequently, the estimation accuracy of the capacity retention rate CR can be improved.

[0066] [Differentiation] Maps 105 and 106 may be stored in the memory of the vehicle ECU 110. In this case, the battery ECU 100 reads maps 105 and 106 from the memory of the vehicle ECU 110 and estimates the capacity retention rate CR.

[0067] Vehicle 1 may also be a hybrid electric vehicle (HEV) further equipped with an engine powered by a fuel such as gasoline or hydrogen. Even in such a case, the battery ECU 100 will determine the amount of charge Ah during the operating period of PCU 80 and MG 90 (the EV driving period of Vehicle 1). j The amount of power degradation d1 is calculated using the total amount of power supplied during a predetermined period, and the time length t of the standing period TPU is calculated. jk The amount of deterioration d2 due to prolonged exposure is calculated using the difference in time length TLb.

[0068] 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]

[0069] 10 Inlet, 20, 60 Converter, 30 Relay, 40 Main Battery, 50 Monitoring Unit, 51 Voltage Sensor, 52 Current Sensor, 53 Temperature Sensor, 70 Auxiliary Battery, 80 PCU, 90 MG, ECU, 100 Battery.

Claims

1. It is a vehicle, Energy storage device, A drive unit that generates the driving force of the vehicle using the power of the aforementioned energy storage device, The processing device includes a first processing method which calculates a first degradation amount of the energy storage device by performing a first processing method which uses the amount of electricity supplied to the energy storage device, and a second processing method which uses the elapsed time during the non-operating period of the drive device to calculate a second degradation amount of the energy storage device, and estimates the capacity maintenance rate of the energy storage device according to the sum of the first degradation amount and the second degradation amount. The vehicle is configured to perform the function of energizing the energy storage device during the non-operation period. The aforementioned processing apparatus is The first process is executed using the amount of electricity supplied during the operating period of the drive device and the total amount of electricity supplied during the non-operating period over the period during which the function is performed. The execution time, which indicates the elapsed time of the execution period, is converted into an estimated time required for the total amount of electricity to be supplied to the energy storage device during the operating period. A vehicle that performs the second process using the elapsed time during the period the vehicle is left idle within the non-operating period and the difference in time obtained by subtracting the guideline time from the execution time.

2. The system further includes a storage unit that stores a first relationship showing the relationship between the temperature of the energy storage device and the energization degradation rate of the energy storage device, and a second relationship showing the relationship between the temperature and SOC of the energy storage device and the storage device's degradation rate when left unattended. The first process includes a process to calculate the first degradation amount by multiplying the square root of the amount of current supplied by the current degradation rate for each temperature of the energy storage device using the first relationship, and then summing up the calculated amounts for all temperatures. The vehicle according to claim 1, wherein the second process includes a process of calculating the second degradation amount by multiplying the square root of the elapsed time length during the non-operating period by the rate of deterioration during the non-operating period for each temperature and SOC of the energy storage device using the second relationship, and then summing up the calculated amounts for all temperatures and all SOCs.

3. The vehicle according to claim 2, wherein the processing device estimates the capacity maintenance rate using the square root of the sum as the degree of deterioration of the energy storage device.

4. Auxiliary battery and The system further comprises a charging device that charges the auxiliary battery using the discharge power from the energy storage device, The vehicle according to any one of claims 1 to 3, wherein the function includes a charging function for the auxiliary battery by the charging device.

5. Power outlet and The vehicle further comprises a power supply device that uses the discharged power from the power storage device to supply power to the outside of the vehicle through the power supply port, The vehicle according to any one of claims 1 to 3, wherein the function includes the function of supplying power to the outside by the power supply device.

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