Display system, vehicle and display method of battery deterioration level

Abstract

To notify a user of an accurate deterioration level of a battery without causing the user discomfort.SOLUTION: A display system 4 includes an instrument panel 5 and an ECU 7 for controlling the instrument panel 5. The ECU 7 repeatedly calculates a full charge capacity of the battery 2 using an amount of change in SOC (State Of Charge) of the battery 2 and an amount of charge / discharge power of the battery 2, and determines a capacity retention rate (a deterioration level) to be displayed on the instrument panel 5 on the basis of a plurality of calculated full charge capacities. The ECU 7 controls the instrument panel 5 to display a capacity retention rate determined by smoothing processing for the plurality of full charge capacities in an area where the rate of change of the plurality of full charge capacities is smaller than a prescribed value, and controls the instrument panel 5 to display a capacity retention rate that has not been smoothed in an area where the rate of change is larger than the prescribed value.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a display system, a vehicle, and a method for displaying a deterioration level of a battery. [Background technology]

[0002] Generally, batteries deteriorate with use or over time. When a battery deteriorates, the battery's full charge capacity decreases, which can reduce user convenience. For this reason, techniques have been proposed for notifying users of the degree of battery deterioration. For example, Japanese Patent Laid-Open Publication No. 2020-58122 (Patent Document 1) discloses a presentation device that can make users aware of specific measures to suppress battery deterioration. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-58122 Summary of the Invention [Problem to be solved by the invention]

[0004] When displaying the deterioration level of a battery, the deterioration level calculated based on the full charge capacity of the battery may vary due to various errors. Therefore, it is conceivable to display the deterioration level after performing a certain amount of processing (more specifically, a smoothing process, which will be described later). However, if there is a discrepancy between the displayed deterioration level and the actual deterioration level, this may cause discomfort to the user. It is desirable to notify the user of the accurate deterioration level of the battery without causing discomfort to the user.

[0005] The present disclosure has been made to solve the above-mentioned problems, and one of the purposes of the present disclosure is to notify a user of an accurate degree of deterioration of a battery without causing the user to feel uncomfortable. [Means for solving the problem]

[0006] (1) A display system according to an aspect of the present disclosure includes a display and a control device that controls the display. The control device repeatedly calculates a full charge capacity of the battery using a change in the battery's State of Charge (SOC) and the amount of charge and discharge power of the battery, and determines a degree of deterioration of the battery to be displayed on the display based on the calculated full charge capacities. The control device controls the display to display a degree of deterioration determined by smoothing the multiple full charge capacities in a region where the rate of change of the multiple full charge capacities is smaller than a predetermined value, and controls the display to display a degree of deterioration that has not been smoothed in an initial region where the rate of change is greater than the predetermined value.

[0007] In the above configuration (1), the smoothing process is not performed in a region where the multiple rates of change in full charge capacity are smaller than a predetermined value (an initial degradation period, described later), and the smoothing process is performed in a region where the multiple rates of change in full charge capacity are larger than the predetermined value (a period after the initial degradation period). By not performing the smoothing process in the initial degradation period, it is possible to prevent the displayed degradation level from deviating from the actual degradation level, which would otherwise occur if the actual degradation level (e.g., capacity retention rate) were to decrease rapidly in the initial degradation period, and therefore it is possible to notify the user of an accurate degradation level. On the other hand, by performing the smoothing process in the period after the initial degradation period, it is possible to notify the user of the degradation level without causing the user to feel uncomfortable. Therefore, according to the above configuration (1), it is possible to notify the user of an accurate degradation level of the battery without causing the user to feel uncomfortable.

[0008] (2) In the smoothing process, the control device weights each of the multiple full charge capacities so that a larger weight is assigned to a newer full charge capacity among the multiple full charge capacities.

[0009] According to the above configuration (2), it is possible to make the new full charge capacity largely reflect the smoothed deterioration degree.

[0010] (3) A vehicle according to another aspect of the present disclosure includes the display system according to (1) or (2) above and a battery. The control device controls the display to display a fixed value indicating that the battery is not degraded as the degradation level when the mileage of the vehicle is less than a predetermined distance or when the time since the vehicle was manufactured is less than a predetermined time.

[0011] If the degradation level displayed on the display increases or decreases due to an error in measuring the degradation level of the battery even though the mileage of the vehicle is less than a predetermined distance (in other words, even though the vehicle is new), the user may feel uncomfortable or dissatisfied. According to the configuration of (3) above, when the mileage is less than a predetermined distance (i.e., when the vehicle is new), the degradation level displayed on the display is set to a fixed value (for example, a capacity maintenance rate of 100%) indicating that the battery is not degraded, thereby reducing the user's discomfort and dissatisfaction.

[0012] (4) A display system according to yet another aspect of the present disclosure includes a display that displays a degree of deterioration of a battery determined based on time-series data of the battery's full charge capacities. The display displays a degree of deterioration determined by smoothing the multiple full charge capacities in a region where the rate of change of the multiple full charge capacities included in the time-series data is smaller than a predetermined value. The display displays a degree of deterioration without smoothing in a region where the rate of change is greater than the predetermined value.

[0013] (5) A method for displaying a degree of deterioration of a battery according to yet another aspect of the present disclosure includes the steps of: calculating multiple full charge capacities of the battery by repeatedly calculating the full charge capacities of the battery using a change in SOC (State Of Charge) of the battery and the amount of charge and discharge power of the battery; and displaying a degree of deterioration of the battery determined based on the multiple full charge capacities on a display. The displaying step includes the steps of displaying a degree of deterioration determined by smoothing the multiple full charge capacities in a region where a rate of change of the multiple full charge capacities is smaller than a predetermined value, and displaying a degree of deterioration without smoothing in an initial region where the rate of change is larger than the predetermined value.

[0014] According to the configuration (4) and the method (5) above, similarly to the configuration (1) above, it is possible to notify the user of the accurate degree of deterioration of the battery without causing the user to feel uncomfortable. [Effects of the Invention]

[0015] According to the present disclosure, it is possible to notify the user of the accurate degree of deterioration of the battery without causing the user to feel uncomfortable. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a diagram showing the overall configuration of a vehicle equipped with a display system according to an embodiment of the present disclosure. [Figure 2] FIG. 10 is a diagram showing an example of a display mode of a battery capacity maintenance rate on an instrument panel. [Figure 3] FIG. 4 is a diagram illustrating an example of a change in a capacity maintenance rate of a battery over time. [Figure 4] FIG. 10 is a conceptual diagram for explaining a method of displaying a battery in a comparative example. [Figure 5] 5A and 5B are conceptual diagrams for explaining a battery display method according to the present embodiment. [Figure 6] 5 is a flowchart showing an example of a processing procedure of a method for displaying a capacity maintenance rate of a battery according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

[0018] In the embodiments described below, a configuration in which a "display system" according to the present disclosure is mounted on a vehicle will be described as an example. However, the use of the "display system" according to the present disclosure is not limited to vehicles. The "display system" may be mounted on a stationary device or a portable device.

[0019] [Embodiment Mode] <System configuration> 1 is a diagram showing the overall configuration of a vehicle equipped with a display system according to an embodiment of the present disclosure. The vehicle 1 includes a battery 2, a monitoring unit 3, and a display system 4.

[0020] The battery 2 is a DC power supply that is configured to be capable of being charged and discharged. The battery 2 is typically a secondary battery such as a lithium ion secondary battery or a nickel-metal hydride battery.

[0021] The monitoring unit 3 monitors the state of the battery 2. More specifically, the monitoring unit 3 includes a voltage sensor that detects the voltage VB of the battery 2, a current sensor that detects the current IB input to and output from the battery 2, and a temperature sensor that detects the temperature TB of the battery 2 (none of which are shown).

[0022] The display system 4 displays various states of the vehicle 1. The display system 4 includes an instrument panel 5, a navigation screen 6, and an ECU (Electronic Control Unit) .

[0023] The instrument panel 5 is an instrument panel on which meters are installed. The instrument panel 5 notifies the user of various states of the vehicle 1 in accordance with control commands from the ECU 7. The instrument panel 5 is an example of a "display" according to the present disclosure.

[0024] The navigation screen 6 is a display provided in the navigation system. The navigation screen 6 notifies the user of various states of the vehicle 1 in accordance with control commands from the ECU 7. The navigation screen 6 is another example of a "display" according to the present disclosure.

[0025] The ECU 7 includes a processor such as a CPU (Central Processing Unit) and an MPU (Micro Processing Unit), memory including a RAM (Random Access Memory) and a ROM (Read Only Memory), and input / output ports (none of which are shown). The ECU 7 outputs control signals based on signals input from various sensors and maps and programs stored in the memory, and controls various devices so that the vehicle 1 is in a desired state. In this embodiment, a main control executed by the ECU 7 is a process of displaying an indicator indicating the deterioration level of the battery 2 on the instrument panel 5. In this embodiment, the capacity maintenance rate of the battery 2 is displayed on the instrument panel 5. The capacity maintenance rate of the battery 2 corresponds to the "deterioration level" according to the present disclosure. The "deterioration level" may be the full charge capacity of the battery 2 itself, or a value converted from the full charge capacity of the battery 2 (for example, the distance that the vehicle 1 can travel when the battery 2 is fully charged). The "deterioration level" may be displayed on another display, such as the navigation screen 6.

[0026] Vehicle 1 is configured to enable plug-in charging, and further includes an inlet 81 connected to charging equipment (not shown) outside the vehicle, a power conversion device 82, a charge relay (CHR: Charge Relay) 83, a system main relay (SMR: System Main Relay) 84, a PCU (Power Control Unit) 84, and a motor generator 86.

[0027] <Display of deterioration level> FIG. 2 is a diagram showing an example of a display manner of the capacity maintenance rate of the battery 2 on the instrument panel 5. The instrument panel 5 is configured to display an icon 92 indicating the capacity maintenance rate of the battery 2 together with an icon 91 indicating the SOC (State Of Charge) of the battery 2. In the example shown in FIG. 2, the icon 92 indicating the capacity maintenance rate of the battery 2 is configured to be displayed as a meter. The meter decreases as the deterioration of the battery 2 progresses. Although not shown, the display manner of the icon 92 is not particularly limited. The icon 92 may be displayed as segments, or may be displayed numerically (as a percentage), for example.

[0028] <Decrease in capacity retention rate> FIG. 3 is a diagram illustrating an example of the change over time in the capacity maintenance rate of battery 2. In FIG. 3 and in FIGS. 4 and 5 described below, the horizontal axis represents the time elapsed since the time t0 of manufacture of vehicle 1 (or battery 2). The capacity maintenance rate of a battery is usually represented by the ratio of the current fully charged capacity of the battery to the fully charged capacity in the battery's initial state (at the time of vehicle manufacture). The horizontal axis may also be interpreted as the mileage of vehicle 1. The vertical axis represents the capacity maintenance rate Q of battery 2. The vertical axis may also be interpreted as the fully charged capacity of the battery (or the mileage that vehicle 1 can travel).

[0029] Generally, the capacity retention rate of a battery may fluctuate slightly due to measurement variations, etc., but basically decreases monotonically over time. It is known that batteries undergo initial degradation. Therefore, as shown in Figure 3, the capacity retention rate of a battery decreases sharply during the initial degradation period (the first few months to several years after the manufacture of vehicle 1 (battery 2)), and then the decrease in the capacity retention rate becomes gradual.

[0030] FIG. 4 is a conceptual diagram for explaining a display method for the battery 2 in the comparative example. As described above, the capacity retention rate of a battery may increase or decrease due to measurement variations and the like. Therefore, it is conceivable to perform smoothing processing on a plurality of capacity retention rates and display the smoothed capacity retention rates on the instrument panel 5. By performing smoothing processing, it is possible to prevent the capacity retention rate from suddenly decreasing or increasing (a recovery that should not occur in reality), and the user can understand the capacity retention rate without feeling uncomfortable.

[0031] The smoothing process is typically a weighted average process. That is, in the weighted average process, each value (in this embodiment, the capacity maintenance rate) is multiplied by a weight corresponding to the value and the result is added (value x weight). Then, the added value is divided by the sum of the weights.

[0032] In the smoothing process, it is desirable to weight each of the multiple capacity retention ratios (full charge capacities) so that a larger weight is assigned to a newer capacity retention ratio among the multiple capacity retention ratios. By weighting a new capacity retention ratio larger than the weight of an old capacity retention ratio, it becomes possible to largely reflect the new capacity retention ratio in the smoothed capacity retention ratio.

[0033] 4, the period from time t0 to t4 is an initial deterioration period (a period during initial deterioration) and corresponds to the "initial region in which multiple rates of change in full charge capacity are greater than a predetermined value" of the present disclosure. The period from time t4 onwards after the end of this period is a period after the initial deterioration period and corresponds to the "region in which multiple rates of change in full charge capacity are smaller than a predetermined value" of the present disclosure.

[0034] In the comparative example, the smoothing process is performed over the entire period. Generally, when the smoothing process is performed, the change in the capacity retention rate becomes more gradual compared to when the smoothing process is not performed. This may result in a discrepancy between the capacity retention rate determined by the smoothing process (i.e., the capacity retention rate displayed on the instrument panel 5) and the actual capacity retention rate. For example, during the initial period, the actual capacity retention rate decreases quickly, whereas the smoothed capacity retention rate does not decrease as quickly. Therefore, the capacity retention rate displayed on the instrument panel 5 may be higher than the actual capacity retention rate. Conversely, after the initial period, the smoothed capacity retention rate decreases due to the influence of initial deterioration, so the capacity retention rate displayed on the instrument panel 5 may be lower than the actual capacity retention rate.

[0035] Therefore, in this embodiment, whether or not the averaging process is performed is switched between the initial deterioration period (the period during initial deterioration) and the period thereafter. The averaging process is not performed during the initial deterioration period, but is performed after the initial deterioration period.

[0036] 5 is a conceptual diagram for explaining a display method for the battery 2 in this embodiment. In this example, during a start period (the period from t0 to t1), which is the earliest period after the manufacture of the vehicle 1, the capacity maintenance rate is displayed as 100% on the instrument panel 5. t1 may be a period from the manufacture of the vehicle 1 until a predetermined short period (for example, one month) has elapsed. t1 may also be a period until the mileage of the vehicle 1 reaches a predetermined short distance (for example, 1000 km).

[0037] If the capacity maintenance rate displayed on the instrument panel 5 exceeds 100% due to a measurement error in the capacity maintenance rate, the user may feel uncomfortable. Furthermore, if the capacity maintenance rate displayed on the instrument panel 5 falls below 100% during the start-up period, the user may feel dissatisfied, thinking, "The capacity maintenance rate dropped quickly despite it being a new car." By fixing the capacity maintenance rate displayed on the instrument panel 5 to 100% during the start-up period, this sense of discomfort and dissatisfaction can be suppressed. Note that a capacity maintenance rate of 100% corresponds to the "fixed value indicating that the battery is not degraded" in the present disclosure.

[0038] During the initial deterioration period (the period from t1 to t3), the smoothing process is not performed, and the actual capacity maintenance rate is displayed as is on the instrument panel 5. This makes it possible to suppress the occurrence of the above-mentioned error caused by the smoothing process.

[0039] During the period after the initial deterioration period (the period after t4), the smoothing process is performed, and the capacity retention rate obtained by the smoothing process is displayed on the instrument panel 5. This makes it possible to suppress variations in the capacity retention rate due to measurement errors of the capacity retention rate.

[0040] <Processing flow> 6 is a flowchart showing an example of the processing procedure of the method for displaying the capacity maintenance rate of the battery 2 in this embodiment. The processing shown in this flowchart is called from a main routine (not shown) and executed every time a predetermined condition is met (for example, at predetermined intervals). In other words, these processing steps are executed repeatedly. Each step is realized by software processing by the ECU 7, but may also be realized by hardware (electrical circuitry) arranged in the ECU 7. Hereinafter, step will be abbreviated as S.

[0041] In S1, the ECU 7 calculates the full charge capacity C of the battery 2. More specifically, the ECU 7 estimates the SOC of the battery 2 before and after charging and discharging the battery 2 (for example, before the start of plug-in charging of the vehicle 1 and after the end of plug-in charging), and obtains the amount of electric energy ΔAh charged and discharged to the battery 2 between the two SOC estimations by current integration using a current sensor. In this case, the ECU 7 can calculate the full charge capacity C of the battery 2 according to the following formula (1) using the results of the two SOC estimation processes, S1 and S2, and the amount of electric energy ΔAh charged and discharged. C = ΔAh / (S1-S2) × 100 (1)

[0042] In S2, the ECU 7 calculates a capacity maintenance rate Q from the full charge capacity C calculated in S2. The capacity maintenance rate Q is the ratio of the current full charge capacity C to the reference capacity Cref, and is calculated according to the following formula (2). The reference capacity Cref is typically the capacity of the battery at the time of manufacture and is determined in advance. The reference capacity Cref is stored in advance in the memory of the ECU 7. Q=C / Cref×100 (2)

[0043] In S3, the ECU 7 determines whether the elapsed period t from the time of manufacture of the vehicle 1 is less than the length of the start period (for example, one month). Alternatively, the ECU 7 may determine whether the travel distance of the vehicle 1 is less than a short distance (for example, 1000 km). If the elapsed period t is less than the length of the start period (YES in S3), the ECU 7 controls the instrument panel 5 so that the capacity maintenance rate Q=100% is fixedly displayed on the instrument panel 5, regardless of the capacity maintenance rate calculated in S2 (S4).

[0044] If the elapsed period t is equal to or longer than the length of the start period (NO in S3), the ECU 7 determines whether the elapsed period t is shorter than the length of the initial deterioration period (for example, several months to several years) (S5). Alternatively, the ECU 7 may determine whether the mileage of the vehicle 1 is less than a medium distance (for example, several thousand kilometers to 10,000 kilometers). If the elapsed period t is shorter than the length of the initial deterioration period (YES in S5), the ECU 7 controls the instrument panel 5 so that the capacity maintenance rate Q calculated in S2 is displayed as is on the instrument panel 5 (S6).

[0045] On the other hand, if the elapsed period t is equal to or longer than the length of the initial deterioration period (NO in S5), the ECU 7 controls the instrument panel 5 so that the smoothed capacity maintenance rate Q is displayed on the instrument panel 5 after the initial deterioration period has elapsed (S7).

[0046] After completing any one of the steps S4, S6, and S7, the ECU 7 returns the process to the main routine, thereby completing the series of processes.

[0047] As described above, in the present embodiment, the smoothing process is not performed during the initial degradation period, and is performed during the period after the initial degradation period. By not performing the smoothing process during the initial degradation period, it is possible to prevent the capacity retention rate displayed on the instrument panel 5 from being higher than the actual capacity retention rate due to a rapid decrease in the actual capacity retention rate during the initial degradation period, and therefore it is possible to notify the user of an accurate capacity retention rate. On the other hand, by performing the smoothing process during the period after the initial degradation period, it is possible to notify the user of the capacity retention rate without causing the user to feel uncomfortable. Therefore, according to the present embodiment, it is possible to notify the user of an accurate capacity retention rate of the battery 2 without causing the user to feel uncomfortable.

[0048] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0049] 1 Vehicle, 2 Battery, 3 Monitoring unit, 4 Display system, 5 Instrument panel, 6 Navigation screen, 7 ECU, 81 Inlet, 82 Power converter, 83 CHR, 84 SMR, 85 PCU, 86 Motor generator, 91, 92 Icons.

Claims

1. The display and a control device for controlling the display, The control device repeatedly calculating a full charge capacity of the battery using a change in SOC (State Of Charge) of the battery and an amount of charge / discharge power of the battery, and determining a deterioration level of the battery to be displayed on the display based on the calculated full charge capacities; controlling the display to display the degree of deterioration determined by smoothing the plurality of full charge capacities in a region where the rate of change of the plurality of full charge capacities is smaller than a predetermined value; A display system that controls the display so that, in an initial region where the rate of change is greater than the predetermined value, the degree of deterioration is displayed without the smoothing process.

2. The display system according to claim 1 , wherein the control device weights each of the plurality of full charge capacities in the smoothing process so that a newer full charge capacity among the plurality of full charge capacities is given a greater weight.

3. A vehicle, A display system according to claim 1 or 2; the battery, The control device controls the display to display a fixed value indicating that the battery is not degraded as the degradation level when the vehicle's mileage is less than a predetermined distance or when the period since the vehicle was manufactured is less than a predetermined time.

4. a display that displays a deterioration level of the battery determined based on time-series data of the full charge capacity of the battery; The display includes: In a region where the rate of change of the plurality of full charge capacities included in the time series data is smaller than a predetermined value, the deterioration degree determined by smoothing the plurality of full charge capacities is displayed; A display system that displays the degree of deterioration without the smoothing process in an area where the rate of change is greater than the predetermined value.

5. calculating a plurality of full charge capacities of the battery by repeatedly calculating the full charge capacities of the battery using a change in SOC (State Of Charge) of the battery and the amount of charge / discharge power of the battery; and displaying on a display the degree of deterioration of the battery determined based on the plurality of full charge capacities; The display step includes a step of displaying the degree of deterioration of a battery determined by smoothing processing of the plurality of full charge capacities in a region where the rate of change of the plurality of full charge capacities is smaller than a predetermined value, and displaying the degree of deterioration without smoothing processing in an initial region where the rate of change is larger than the predetermined value.

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