Vehicle

Abstract

The present application aims to improve the estimation accuracy of the capacity maintenance rate of a vehicle's drive storage device. The vehicle is provided with a main battery, a PCU and an MG, and a battery ECU. The battery ECU calculates the on-load deterioration amount and the standing deterioration amount by executing first and second processes, and estimates the capacity maintenance rate from the sum of these amounts. The vehicle is configured to be able to execute a function of on-loading the main battery during the parking period. The battery ECU uses the total amount of the on-load electric quantity during the running period and the on-load electric quantity during the execution period of the function throughout the parking period to execute the first process, converts the execution time length representing the elapsed time length of the execution period into a reference time length required to on-load the total amount of the on-load electric quantity to the storage device during the running period, and uses the elapsed time length of the standing period of the vehicle during the parking period and the difference time length obtained by subtracting the reference time length from the execution time length to execute the second process.

Description

Technical Field

[0001] This invention relates to a vehicle. Background Technology

[0002] Japanese Patent Application 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 includes 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 variation in SOC in the time-series data acquired by the acquisition unit to calculate a current-charge degradation value representing degradation caused by energizing the energy storage element, and estimates the degradation of the energy storage element based on the sum of the calculated current-charge degradation value and a non-energized degradation value representing degradation not caused by energizing the energy storage element.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2019-53074 Summary of the Invention

[0004] Vehicles equipped with driving-use energy storage devices are becoming increasingly common. When estimating the capacity retention rate of such energy storage devices based on the sum of the degradation caused by energizing the device and the degradation not caused by energizing it, a high-precision estimate of the capacity retention rate is required.

[0005] The present invention was made to solve the problems described above, and its purpose is to improve the estimation accuracy of the capacity maintenance rate of the energy storage device for vehicle operation.

[0006] The vehicle of the present invention includes an energy storage device, a drive unit, and a processing device. The drive unit uses the power from the energy storage device to generate the driving force for the vehicle. The processing device calculates a first degradation amount of the energy storage device by performing a first processing step using the energized amount of the energy storage device, and calculates a second degradation amount of the energy storage device by performing a second processing step using the elapsed time length of the non-operation period of the drive unit, and estimates the capacity maintenance rate of the energy storage device based on the sum of the first degradation amount and the second degradation amount. The vehicle is configured to perform a function that energizes the energy storage device during non-operation periods. The processing device performs the first processing step using the total energized amount of the drive unit during operation periods and the total energized amount of the function during execution periods during non-operation periods, converts the execution time length, which represents the elapsed time length of the execution period, into a reference time length required to energize the energy storage device with the total energized amount of the energy during operation periods, and performs the second processing step using the elapsed time length of the vehicle's placement period during non-operation periods and the difference time length between the execution time length and the reference time length.

[0007] By configuring the structure described above, the total amount of electricity supplied during the operation of the drive device and the total amount of electricity supplied during the execution of the storage device are reflected in the first degradation level. Furthermore, the differential time length, depending on the duration of the storage period, is reflected in the second degradation level. Therefore, the sum of the first and second degradation levels accurately represents the degree of degradation of the storage device. As a result, the capacity retention rate can be accurately estimated based on this sum. Thus, the accuracy of estimating the capacity retention rate of the storage device can be improved.

[0008] In one aspect, the vehicle also includes a storage unit. The storage unit stores a first relationship representing the relationship between the temperature of the energy storage device and the rate of degradation during charging, and a second relationship representing the relationship between the temperature and state of charge (SOC) of the energy storage device and the rate of degradation during storage. The first process includes the following steps: for each temperature of the energy storage device, using the first relationship, calculate the amount obtained by multiplying the square root of the charged quantity by the rate of degradation during charging, and calculate the first degradation amount by summing the amounts calculated for all temperatures. The second process includes the following steps: for each temperature and SOC of the energy storage device, using the second relationship, calculate the amount obtained by multiplying the square root of the elapsed time during non-operational periods by the rate of degradation during storage, and calculate the second degradation amount by summing the amounts calculated for all temperatures and all SOCs.

[0009] In one respect, the processing device uses the square root of the sum as the degree of degradation of the energy storage device to estimate the capacity maintenance rate.

[0010] In some cases, the vehicle also features an auxiliary battery and a charging device. The charging device uses the discharged electricity from the energy storage device to charge the auxiliary battery. Functions include charging the auxiliary battery based on the charging device.

[0011] In some cases, the vehicle also has a power supply port and a power supply device. The power supply device uses the discharged electricity from the energy storage device to supply power to the outside of the vehicle through the power supply port. Functions include the ability to supply power to the outside based on the power supply device.

[0012] Invention Effects

[0013] According to the present invention, the estimation accuracy of the capacity maintenance rate of the energy storage device for vehicle operation can be improved. Attached Figure Description

[0014] Figure 1 This is a block diagram illustrating an example of the overall structure of a vehicle according to this embodiment.

[0015] Figure 2 This is a diagram used to illustrate the mapping table stored in the memory of the battery ECU (Electronic Control Unit).

[0016] Figure 3 This is a graph showing the usage of the main battery during a 24-hour parking period.

[0017] Figure 4 This is a flowchart illustrating an example of the order of estimation processing in this embodiment.

[0018] Figure 5 This is a diagram representing the driving simulation mode used to calculate the electrical degradation coefficient aj.

[0019] Figure 6 This is a diagram illustrating the calculation method for the degradation factor bjk. Detailed Implementation

[0020] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Identical or corresponding parts in the drawings will be labeled with the same symbols without repetition of descriptions. Various embodiments and their modifications can be appropriately combined with each other.

[0021] Figure 1 This is a block diagram illustrating an example of the overall structure of a vehicle according to this embodiment. (See reference) Figure 1 Vehicle 1 is an electric vehicle (BEV: Battery Electric Vehicle).

[0022] Vehicle 1 includes: charging port 10, AC / DC converter 20, relay 30, main battery 40, monitoring unit 50, DC / DC converter 60, auxiliary battery 70, PCU (Power Control Unit) 80, MG (Motor Generator) 90, battery ECU 100 and vehicle ECU 110.

[0023] The charging port 10 is configured to be inserted into a charging connector located at the front end of the charging cable 901. The charging port 10 is an example of the "power supply port" of the present invention.

[0024] The AC / DC converter 20 converts AC power supplied from an external power source (not shown) located outside the vehicle 1 via charging cable 901 and charging port 10 into DC power, and uses this DC power to charge the main battery 40 (external charging). The AC / DC converter 20 can also convert the DC power discharged from the main battery 40 into AC power, and use this AC power to supply power to an external load 902 via charging port 10 (external power supply). The external load 902 is, for example, a house, but can also be various electrical devices. The AC / DC converter 20 is an example of the "power supply device" of this invention.

[0025] Relay 30 is electrically connected to the power line connecting AC / DC converter 20 and main battery 40. Relay 30 opens and closes according to control commands from vehicle ECU 110.

[0026] 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 driving power of the vehicle 1. The main battery 40 is an example of the "energy storage device" of the present invention.

[0027] The monitoring unit 50 includes a voltage sensor 51, a current sensor 52, and a temperature sensor 53. The voltage sensor 51, the current sensor 52, and the 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.

[0028] The DC / DC converter 60 charges the auxiliary battery 70 using the discharge power from the main battery 40 (auxiliary device suction) according to control commands from the vehicle ECU 110. The DC / DC converter 60 is an example of the "charging device" of the present invention. The auxiliary battery 70 stores the driving power for auxiliary devices (not shown) of the vehicle 1.

[0029] PCU80 drives MG90 using power from the main battery 40 according to control commands from the vehicle ECU110. MG90 rotates the drive shaft of vehicle 1, generating driving force for vehicle 1. The operating and non-operating periods of PCU80 and MG90 correspond to the driving and stationary periods of vehicle 1, respectively. PCU80 and MG90 are examples of the "drive unit" of the present invention.

[0030] The battery ECU 100 includes a processor 101 and a memory 102. The processor 101 is, for example, a central processing unit (CPU). The memory 102 includes ROM (Read Only Memory) and random access memory (RAM). The ROM stores various mapping tables and programs.

[0031] The battery ECU 100 manages the main battery 40 based on input signals from various sensors in the monitoring unit 50, as well as a map and program stored in the memory 102. For example, the battery ECU 100 calculates the SOC of the main battery 40 sequentially based on detected values ​​of voltage V, current I, and temperature T, and stores this information in the memory 102. As a result, a history of these detected values ​​is generated in the memory 102.

[0032] Like the battery ECU 100, the vehicle ECU 110 includes a processor and a memory (neither shown). The vehicle ECU 110 controls various devices such as the AC / DC converter 20, relay 30, DC / DC converter 60, and PCU 80 to bring the vehicle 1 into a desired state based on the input signals from the various sensors installed in the vehicle 1 and the map and program stored in the memory.

[0033] The vehicle ECU 110, for example, controls the PCU 80 to generate driving force for the MG90, or controls various devices to perform the prescribed function of energizing the main battery 40 when the vehicle 1 is stationary. In one example, the prescribed function is the charging function of the main battery 40 based on the AC / DC converter 20 (external charging), the power supply function from the main battery 40 to the external load 902 based on the AC / DC converter 20 (external power supply), or the charging function from the main battery 40 to the auxiliary battery 70 based on the DC / DC converter 60 (auxiliary device suction).

[0034] The following is a detailed description of the processing by the battery ECU 100. 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.

[0035] The battery ECU100 is configured to execute two logics during the estimation process: power-on degradation logic and placement degradation logic. These logics correspond to the "first process" and "second process" of this invention, respectively.

[0036] The power-on degradation logic uses the charge level of the main battery 40 (e.g., the charge level during vehicle 1's operation) [unit: Ah] to calculate the amount of degradation associated with the power supply of the main battery 40. The charge level of the main battery 40 is also simply referred to as "charge level". The battery ECU 100 calculates the charge level at each predetermined time interval (e.g., 1 second) based on the detected current I, associates this charge level with the detected temperature T within that time interval, and stores them sequentially in the memory 102. The amount of degradation associated with the power supply depends on the temperature of the main battery 40. The higher the temperature of the main battery 40, the greater the degradation.

[0037] The battery ECU 100 calculates the charge on the main battery 40 at each temperature T during the period in which the charge-on degradation is calculated (e.g., during driving). The battery ECU 100 calculates the degradation associated with the charge on the main battery 40 at each temperature T within the aforementioned period, based on the charge. The battery ECU 100 calculates the charge-on degradation amount d1 by summing the calculated degradation amounts across all temperatures.

[0038] More specifically, the battery ECU100 calculates the amount of power-on degradation d1 in the power-on degradation logic according to the following formula (1).

[0039] [Formula 1]

[0040]

[0041] In equation (1), j is a natural number (j=1, 2, ..., J) used to distinguish the temperature (battery temperature) of the main battery 40. Power supply Ah j This represents the charge capacity of the main battery 40 at the corresponding battery temperature. The charge degradation coefficient α j This represents the amount of electricity delivered per unit of charge (Ah) at the corresponding battery temperature. j The square root of the degradation amount of the main cell 40 is the rate of degradation during power supply. The degradation coefficient 'a' is the rate of degradation during power supply. j The scenario envisions supplying the PCU80 and MG90 with the power required to achieve the driving simulation mode described later, while the driving conditions of the vehicle 1 are determined through prior evaluation tests, etc.

[0042] The placement degradation logic is a process that uses the elapsed time during which vehicle 1 is parked (e.g., the elapsed time of vehicle 1's placement period) to calculate the amount of degradation of the main battery 40 over time. This amount of degradation is also referred to as the "placement degradation amount". The placement period of vehicle 1 is part of the parking period, typically the period during which the vehicle 1's driving system is in the ReadyOFF state and the main battery 40 is not powered. The ReadyOFF state refers to the state in which the main battery 40 is electrically isolated from other devices of vehicle 1 by means of disconnection of a system main relay (SMR) (not shown) located on the main battery 40.

[0043] The amount of degradation depends on the temperature and SOC of the main battery 40. The higher the temperature of the main battery 40, the greater the degradation, and the higher the SOC of the main battery 40, the greater the degradation. Therefore, the battery ECU 100 calculates the amount of degradation of the main battery 40 over time corresponding to the elapsed time during parking for each combination of temperature and SOC, and adds the calculated degradation amounts to all combinations (temperature and SOC) to calculate the degradation amount d2. The elapsed time is associated with each combination and stored in the memory 102.

[0044] More specifically, the battery ECU100 calculates the placement degradation amount d2 in the placement degradation logic according to the following formula (2).

[0045] [Formula 2]

[0046]

[0047] In equation (2), j is a natural number used to distinguish battery temperature (j=1, 2, ..., J). k is a natural number used to distinguish SOC (k=1, 2, ..., K). Time length t jk This refers to the length of time corresponding to the battery temperature and SOC during the period (e.g., storage period) during which the degradation amount d2 is calculated. In this example, the time length t... jk It is expressed in days, but can also be expressed in hours [h], for example. Place the degradation factor b. jk This represents the length of time t per unit of time at the corresponding battery temperature and SOC. jk The deterioration rate of the main battery 40 is the square root of its deterioration.

[0048] Figure 2 This is a diagram illustrating the mapping table stored in the memory 102 of the battery ECU 100. (Reference) Figure 2 Mapping table 105 shows the relationship between the temperature T of the main battery 40 and the degradation coefficient a during power supply. j The correspondence between them. Regarding the electrical degradation coefficient 'a'. j The value is determined by prior evaluation tests and other methods within a temperature range of -45℃ to 65℃.

[0049] Mapping Table 106 shows the relationship between temperature T, SOC, and the storage degradation factor b. jk The correspondence between them. Place the degradation coefficient b. jk The SOC (State of Charge) is determined through prior evaluation tests, etc., for every 1°C within a temperature range of -45°C to 65°C, and for every 10% to 20% SOC width within a range of 0% to 100%. In this example, J=111 and K=7. Regarding the current-carrying degradation factor a... j and placement degradation coefficient b jk For detailed calculation methods, please refer to [reference]. Figure 5 and Figure 6 Please provide an explanation.

[0050] The battery ECU100 uses mapping table 105 to determine the current degradation factor a corresponding to temperature T. j Similarly, the battery ECU 100 uses mapping table 106 to determine the placement degradation factor b corresponding to the combination of temperature T and SOC. jk .

[0051] Battery ECU100 uses an electrical degradation coefficient a j The electrical degradation d1 is calculated according to formula (1), and the placement degradation coefficient b is used. jkThe placement degradation amount d2 is calculated according to formula (2). Then, the battery ECU 100 estimates the capacity retention rate CR of the main battery 40 based on the sum D of the power-on degradation amount d1 and the placement 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, where the square root of the sum D represents the degree of degradation of the main battery 40 (the degree of reduction in full-charge capacity) (refer to formula (3) below).

[0052] CR=100-√D...(3)

[0053] When using equations (1) to (3) to estimate the capacity maintenance ratio CR, the estimation accuracy of the capacity maintenance ratio CR tends to decrease in the comparative examples described below. This point will be explained below.

[0054] Figure 3 This is a graph showing the usage of the main battery 40 during a 24-hour parking period. (Reference) Figure 3 In the comparative example and any of the embodiments described herein, the power consumption during the driving period is used to calculate the power consumption degradation d1 according to formula (1), the storage degradation d2 is calculated according to formula (2) using the elapsed time during the storage period, and the capacity retention rate CR is estimated according to formula (3) using the sum of these degradation values ​​D.

[0055] In this example, we will describe a situation where a vehicle 1 is placed for 16 hours while the prescribed function is performed for 8 hours on a given day. The elapsed time of the prescribed function's execution period (TPF) and the vehicle 1's placement period (TPU) will also be represented as the execution time length (TLF) and placement time length (TLU), respectively. These periods are all part of the non-operational periods of the PCU80 and MG90. The execution time length (TLF) and placement time length (TLU) are stored in the memory 102 of the battery ECU100.

[0056] During the operation of the TPF, the value of current I (battery current value) is significantly smaller (in one example, by one or two orders of magnitude) compared to the value of current I during driving. For example, the reference value of the battery current during driving (reference driving current value) is 50A, compared to 5A when powered externally and 0.2A when the auxiliary device is pumping. The reference driving current value is appropriately preset, for example, as an average of the battery current during driving, through prior evaluation tests. In this example, when the auxiliary device is pumping for the specified function, the total charge of the main battery 40 of the TPF during the operation is 1.6Ah (=0.2A×8h). This total is also referred to as the "total charge during the specified period".

[0057] The method for estimating the capacity retention rate CR in the comparative example will be explained below. As mentioned above, the specified function is a low-rate power-on function, while Equation (1) is based on a high-rate power-on function during operation. In order to estimate the capacity retention rate CR, which takes into account the degradation of the main battery 40 in the TPF during the operation period, directly applying the power-on amount and temperature T in the TPF during the operation period to Equation (1) would lead to a decrease in the estimation accuracy of the capacity retention rate CR. In the comparative example, it is assumed that the power-on of the total power-on amount during the specified period is carried out at a high-rate power-on function, and the power-on degradation amount d1 is calculated using Equation (1), and the capacity retention rate CR is estimated based on the calculation result. For example, the power-on amount Ah corresponding to the average battery temperature in the TPF during the operation period is... a (The charge Ah when j=a) j The total amount of electricity consumed during the specified period, in lieu of the total electricity consumed (Ah), is used to replace the total electricity consumed. a The electrical degradation d1 is calculated using formula (1). (In addition, for values ​​of j other than a, the total electrical charge during the specified period is not considered, and the electrical charge Ah during the driving period is used.) j Calculate the current degradation d1). However, in the comparative example, the capacity retention rate CR was estimated to be higher than the actual capacity retention rate CR, and therefore it is possible that the estimate is inaccurate.

[0058] Therefore, the battery ECU 100 of the vehicle 1 according to the embodiment has a structure for more accurately estimating the capacity retention rate CR. Specifically, the battery ECU 100 uses the charge Ah during driving, as in the comparative example. j The power consumption degradation d1 is calculated using the total power consumption during the specified period, and the storage degradation d2 is calculated using the storage time length TLU and the differential time length TLb (described later). The method for calculating the storage degradation d2 by the battery ECU100 is described in detail below.

[0059] First, the battery ECU 100 converts the execution time length TLF into a reference time length TLA. The reference time length TLA is a reference to the time required for the total charge in the main battery 40 to be energized during the specified period of driving. The battery ECU 100 calculates the reference time length TLA by dividing the total charge within the specified period by the reference driving current value. In this example, the reference time length TLA is 0.032 (=1.6 / 50) [days].

[0060] Next, the battery ECU100 calculates the differential time length TLb by subtracting the reference time length TTa from the execution time length TLF. In this example, the differential time length TLb is 7.97 (=8 - 0.032) [days].

[0061] Then, the battery ECU100 usage time length t jkThe differential time length TLb is used to calculate the placement degradation amount d2 according to formula (2). For example, the battery ECU 100 will establish an association with the combination of temperature T, which is equal to the average temperature T in the TPF during the execution period, and SOC, which is equal to the average SOC in the TPF during the execution period, and store the time length t in memory 102. bc (Time length t when j=b, k=c) jk The total time length t replaced by the differential time length TLb. bc And calculate the placement degradation amount d2 according to formula (2). (In addition, for the values ​​of j other than b and the values ​​of k other than c, the differential time length TLb is not considered, but the time length t in the TPU during the placement period is used.) jk Calculate the placement degradation amount d2).

[0062] As described above, after calculating the power-on degradation amount d1 and the placement degradation amount d2, the battery ECU100 uses the sum of these degradation amounts D to estimate the capacity retention rate CR according to formula (3).

[0063] The comparative example is equivalent to assuming that the main cell 40 does not deteriorate at all during the differential time length TLb, and calculating the degree of deterioration of the main cell 40 (and the square root of D) according to equations (1) to (3) and estimating the capacity retention rate CR. As a result, in the comparative example, D was calculated to be smaller than actual and the capacity retention rate CR was estimated to be higher than actual.

[0064] In contrast, according to the implementation method, in addition to the power consumption Ah during driving... j In addition, the total power consumption during the specified period is also reflected in the power consumption degradation d1. On the other hand, besides the placement time TLU time t jk In addition, the differential time length TLb is also reflected in the placement degradation amount d2. Therefore, compared to the comparative example, and D are calculated to be slightly larger, and the square root of and D accurately represents the degradation degree of the main cell 40. As a result, the error between the estimated and actual values ​​of the capacity retention rate CR is reduced. Therefore, the estimation accuracy of the capacity retention rate CR can be improved.

[0065] Figure 4 This is a flowchart illustrating an example of the order of estimation processes in this embodiment. The flowchart is executed according to each predetermined control cycle (24 hours in this example). Hereinafter, each step will be abbreviated as "S".

[0066] In S10, the battery ECU 100 determines whether a specified function has been performed within the last 24 hours (S10). For example, the battery ECU 100 determines whether the length of the period during which the value of current I is greater than zero and less than a reference current value (5A in one example) is greater than a specified time. If this period is greater than the specified time, it is considered that this period is the execution period TPF, and the specified function is determined to have been performed. In this case, it is determined that the specified function has not been performed.

[0067] If the specified function is performed ("Yes" in S10), the battery ECU 100 calculates the total charge during the specified period based on the history of the detected current I (S12). The battery ECU 100 uses the charge Ah stored in the memory 102 during the driving period. j The power degradation logic of the total power consumption within the specified period is used to calculate the power degradation amount d1 (S14) according to formula (1).

[0068] The battery ECU 100 converts the execution time length TLF into a reference time length TLA by dividing the total charge applied during a specified period by a reference driving current value (S16). The battery ECU 100 calculates the differential time length TLb by subtracting the reference time length TLA from the execution time length TLF, and uses the placement time length TLU (specifically, the placement period TLU duration t). jk The placement degradation logic of the differential time length TLb is calculated according to the formula (2) to calculate the placement degradation amount d2 (S17).

[0069] If the specified function is not performed ("No" in S10), the battery ECU100 calculates the amount of electricity (Ah) used during driving. j The power-on degradation logic calculates the power-on degradation amount d1 according to formula (1) (S18). Next, the battery ECU100 uses the time length t of the storage period TLU. jk The placement degradation logic is calculated according to formula (2) to determine the placement degradation amount d2 (S19). S18 and S19 are equivalent to the processing in S14 and S17 where the total charge is zero within a specified period.

[0070] The battery ECU100 uses the sum of the on-current degradation d1 and the placement degradation d2 D to estimate the capacity retention rate CR (S20) according to formula (3).

[0071] Figure 5 This represents the coefficient 'a' used to calculate the degradation factor during electrical conduction. j A diagram of the driving simulation mode (i.e., the power-on mode of a battery of the same type as the main battery 40). Figure 5(A) shows the shift in battery current value during one cycle of driving simulation mode (left column) and the shift in battery SOC during this mode (right column). This is to calculate the on-state degradation factor a. j A battery endurance test was conducted with the ambient temperature maintained at a constant level. Specifically, the battery was repeatedly charged and discharged in a driving simulation mode with varying current values ​​and SOC (State of Charge) as shown in the figure, under constant ambient temperature.

[0072] Figure 5 (B) represents the measured result of the capacity retention rate (CR) of the battery after the above-described power-on durability test. Typically, the decrease in capacity retention rate (CR) accompanying power-on is proportional to the square root of the charge applied to the main battery 40. Therefore, as... Figure 5 As shown in (B), if the charge of the main battery 40 is taken on the horizontal axis and the capacity retention rate CR of the main battery 40 is taken on the vertical axis, then the relationship between the capacity retention rate CR and the square root of the charge is represented by a straight line. The slope of this straight line is equivalent to the charge degradation coefficient a. j In this example, the electrical degradation coefficient α at 25°C is... j The electrical degradation coefficient α at 40°C is 0.0005. j The electrical degradation coefficient α at 60°C is 0.0007. j It is 0.001.

[0073] Figure 6 This illustrates the placement degradation factor b. jk The calculation method is illustrated in the diagram. Generally, under the condition of equal SOC, the decrease in capacity retention rate (CR) over time is proportional to the square root of the elapsed time. Therefore, as... Figure 6 As shown, if we take the square root of the elapsed time (number of days) on the horizontal axis and the capacity maintenance rate CR on the vertical axis, then the relationship between the capacity maintenance rate CR and the square root of the elapsed time is also represented by a straight line. The slope of this line is equivalent to placing the degradation factor b. jk In this example, at SOC=90%, the degradation factor b at 25°C is... jk The degradation coefficient b at 40°C is 0.006. jk The degradation coefficient b at 60°C is 0.009. jk The value is 0.01. Although not illustrated, the same straight line can be obtained under the same temperature but different SOC conditions.

[0074] As described above, in this embodiment, in addition to the power consumption Ah during driving... j In addition, the total power consumption during the specified period is also reflected in the power consumption degradation d1. Furthermore, besides the time t of the TPU during the storage period... jkIn addition, the differential time length TLb is also reflected in the placement degradation amount d2. Therefore, the square root of D accurately represents the degradation degree of the main cell 40, thus reducing the error between the estimated and actual capacity retention rate CR. Consequently, the estimation accuracy of the capacity retention rate CR can be improved.

[0075] [Variation Example]

[0076] Mapping tables 105 and 106 can be stored in the memory of the vehicle ECU 110. In this case, the battery ECU 100 reads mapping tables 105 and 106 from the memory of the vehicle ECU 110 and estimates the capacity retention rate CR.

[0077] Vehicle 1 can be a hybrid electric vehicle (HEV) that also has an engine powered by fuels such as gasoline or hydrogen. Even in this case, the battery ECU 100 uses the charge Ah delivered during the operation of PCU80 and MG90 (during the EV driving period of vehicle 1). j The electrical degradation d1 is calculated based on the total electrical charge applied during the specified period, and the duration t of the TPU during the placement period is also used. jk The placement degradation amount d2 is calculated using the differential time length TLb.

[0078] It should be considered that the embodiments disclosed herein are illustrative in all respects and not restrictive. The scope of the invention is not shown in the foregoing description, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0079] Symbol Explanation

[0080] 10 - Charging port; 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; 100 - Battery ECU.

Claims

1. A vehicle, characterized in that, have: Energy storage devices; A drive unit that uses the electricity from the energy storage device to generate the driving force for the vehicle; and The processing device calculates a first degradation amount of the energy storage device by performing a first processing step using the energized amount of the energy storage device, and calculates a second degradation amount of the energy storage device by performing a second processing step using the elapsed time length during the non-operation period of the drive device, and estimates the capacity maintenance rate of the energy storage device based on 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-operational period. The processing device performs the first processing using the total amount of power supplied during the operation of the drive device and the total amount of power supplied during the execution of the function throughout the non-operation period. The execution time length, which represents the elapsed time during the execution period, is converted into a reference time length required to energize the total amount of energized electricity into the energy storage device during the operation. The second process is performed using the elapsed time length of the vehicle's placement period during the non-operation period and the difference time length between the execution time length and the reference time length.

2. The vehicle according to claim 1, characterized in that, It also has: The storage unit stores a first relationship relating the temperature of the energy storage device to the rate of degradation during power-on, and a second relationship relating the temperature and state of charge (SOC) of the energy storage device to the rate of degradation during storage. The first process includes the following steps: for each temperature of the energy storage device, using the first relationship, calculating the amount obtained by multiplying the square root of the energized charge by the energization degradation rate, and calculating the first degradation amount by adding the amounts calculated for all temperatures. The second process includes the following steps: for each temperature and SOC of the energy storage device, using the second relationship, calculating the amount obtained by multiplying the square root of the elapsed time length during the non-operation period by the placement degradation rate, and calculating the second degradation amount by adding the amounts calculated for all temperatures and all SOCs.

3. The vehicle according to claim 2, characterized in that, The processing device estimates the capacity retention rate by taking the square root of the sum as the degree of degradation of the energy storage device.

4. The vehicle according to any one of claims 1 to 3, characterized in that, It also has: Auxiliary battery; and A charging device that uses the discharge power from the energy storage device to charge the auxiliary battery. The function includes the charging function based on the auxiliary battery of the charging device.

5. The vehicle according to any one of claims 1 to 3, characterized in that, It also has: Power supply port; and A power supply device that uses the discharged power from the energy storage device to supply power to the outside of the vehicle through the power supply port. The function includes the ability to supply power to the outside based on the power supply device.

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