Battery system

Abstract

To eliminate discomfort in display change of the degree of deterioration of a secondary battery.SOLUTION: A control device executes a process including steps of: if a display update condition holds (YES at S100), acquiring a charging / discharging history (S102); estimating the degree of deterioration of a battery (S104); acquiring a threshold for segment display (S106); if the degree of deterioration is less than the threshold (YES at S108) and the elapse of a predetermined time is determined (YES at S110), updating the segment display (S112); and updating display of a numerical value (S114).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a battery system. [Background technology]

[0002] International Publication No. 2020 / 234982 (Patent Document 1) discloses a technology for controlling a display unit so that after an operation is performed on an execution switch to display battery calibration information, the display is based on the ratio of the battery's full charge capacity at that time to the full charge capacity at the time the operation was performed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2020 / 234982 Summary of the Invention [Problem to be solved by the invention]

[0004] However, for example, when the degree of deterioration of a secondary battery such as a battery is calculated using the full charge capacity of the secondary battery and the calculated degree of deterioration is displayed, the change in the displayed degree of deterioration during a period when the amount of change in the initial full charge capacity of the secondary battery is large may cause the user to feel uncomfortable.

[0005] The present disclosure has been made to solve the above-mentioned problems, and its purpose is to provide a battery system that does not cause discomfort when changes in the display of the deterioration level of a secondary battery occur. [Means for solving the problem]

[0006] A battery system according to an aspect of the present disclosure includes a secondary battery mounted on a vehicle, a control device that calculates a deterioration level of the secondary battery, and a display device that displays the deterioration level using a numerical value and a number of segments. The control device causes the display device to display a set number of segments according to a weighting corresponding to the deterioration level.

[0007] In this way, a set number of segments are displayed according to weighting corresponding to the degree of deterioration, so that, for example, by setting the weighting so that the change in the number of segments is gradual during a period in which the degree of deterioration changes suddenly, it is possible to prevent the user from feeling uncomfortable about the change in the degree of deterioration.

[0008] In one embodiment, the weighting is set so that the timing at which the number of segments changes is the same when the secondary battery is in an initial state as when it is not in an initial state.

[0009] In this way, the timing at which the number of segments changes is set to be the same whether the state is in the initial state or not, thereby preventing the user from feeling uncomfortable about the change in the deterioration level during a period when the deterioration level changes suddenly.

[0010] In yet another embodiment, the control device varies the number of segments displayed based on a predetermined period or a predetermined degree of deterioration.

[0011] In this way, the number of segments to be displayed changes based on a predetermined period or a predetermined degree of deterioration, thereby preventing the user from feeling uncomfortable about changes in the degree of deterioration during periods when the degree of deterioration changes suddenly. [Effects of the Invention]

[0012] According to the present disclosure, it is possible to provide a battery system in which the change in the display of the deterioration level of a secondary battery does not cause discomfort. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a vehicle equipped with a battery system. [Figure 2] 4 is a flowchart illustrating an example of a process executed by a control device. [Figure 3] FIG. 2 is a diagram illustrating an example of a display screen displayed on a display device. DETAILED DESCRIPTION OF THE INVENTION

[0014] 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.

[0015] The configuration of a vehicle equipped with a battery system according to this embodiment will be described below. Fig. 1 is a diagram showing an example of the configuration of a vehicle 1 equipped with a battery system 4.

[0016] In this embodiment, the vehicle 1 will be described as an electric vehicle, but any electrically powered vehicle, such as a hybrid vehicle, may be used. As shown in FIG. 1, the vehicle 1 includes a drive system 2 and a battery system 4.

[0017] The drive system 2 includes an electric load of the battery system 4. Specifically, the drive system 2 includes a motor generator (MG) 10, a power transmission gear 20, and drive wheels 30.

[0018] The MG 10 is, for example, a three-phase AC rotating electric machine that functions as both an electric motor (motor) and a generator. The output torque of the MG 10 is transmitted to the drive wheels 30 via a power transmission gear 20 that includes a reduction gear, a differential gear, and the like.

[0019] When braking the vehicle 1, the MG 10 is driven by the drive wheels 30 and operates as a generator. This allows the MG 10 to function as a braking device that performs regenerative braking to convert the kinetic energy of the vehicle 1 into electric power. The regenerative power generated by the regenerative braking force in the MG 10 is supplied to the battery system 4.

[0020] The battery system 4 includes a power control unit (PCU) 40, a system main relay (SMR) 50, a battery 100, a monitoring unit 200, a control device 300, and a display device 400.

[0021] The PCU 40 is a power conversion device that converts power bidirectionally between the MG 10 and the battery 100. The PCU 40 includes, for example, an inverter and a converter.

[0022] The converter boosts the voltage supplied from the battery 100 when the battery 100 is discharging and supplies the boosted voltage to the inverter. The inverter converts the DC power supplied from the converter into AC power to drive the MG 10.

[0023] On the other hand, the inverter converts AC power (regenerative power) generated by the MG10 into DC power and supplies it to the converter when charging the battery 100. The converter steps down the voltage supplied from the inverter to a voltage suitable for charging the battery 100 and supplies it to the battery 100.

[0024] Furthermore, the PCU 40 suspends charging and discharging by stopping the operation of the inverter and the converter. The PCU 40 may be configured without the converter.

[0025] The SMR 50 is electrically connected to a power line connecting the battery 100 and the PCU 40. When the SMR 50 is closed (i.e., in a conductive state), power can be exchanged between the battery 100 and the PCU 40. On the other hand, when the SMR 50 is open (i.e., in a disconnected state), the electrical connection between the battery 100 and the PCU 40 is cut off.

[0026] Battery 100 is a power storage device that stores power for driving MG 10. Battery 100 is a rechargeable DC power supply, and is configured, for example, by connecting a plurality of cells in series. The cells include, for example, secondary batteries such as nickel-metal hydride batteries or lithium-ion batteries. Battery 100 may also be configured, for example, by connecting a plurality of parallel battery blocks in series, each of which is configured by connecting a plurality of cells in parallel.

[0027] The monitoring unit 200 is provided in the battery 100. The monitoring unit 200 includes a voltage detection unit 210, a current detection unit 220, and a temperature detection unit 230. The voltage detection unit 210 detects the voltage VB between the terminals of the battery 100. The current detection unit 220 detects the current IB input to or output from the battery 100. The temperature detection unit 230 detects the temperature TB of the battery 100. Each detection unit outputs its detection result to the control device 300. Note that the monitoring unit 200 may, for example, store information indicating a history of various detection results in a memory (not shown), and output the information stored in the memory to the control device 300 every time a predetermined time elapses.

[0028] The control device 300 includes a CPU (Central Processing Unit) 301 and a memory 302. The memory 302 includes, for example, a ROM (Read Only Memory) and a RAM (Radom Access Memory). The control device 300 controls the display device 400 based on signals received from the monitoring unit 200 and information such as maps and programs stored in the memory 302. The various controls performed by the control device 300 are not limited to software processing, but can also be processed by dedicated hardware (electronic circuits). The control device 300 is configured, for example, by an ECU (Electronic Control Unit).

[0029] The control device 300 stores the detection values ​​from the monitoring unit 200 in a memory 302. The control device 300 has a function of successively calculating the SOC (State Of Charge) of the battery 100 based on the detection values ​​from the voltage detection unit 210, the current detection unit 220, and the temperature detection unit 230. The SOC indicates the current amount of charge stored in the battery 100 as a percentage. Various known methods can be used to calculate the SOC, such as a method based on current value integration (coulomb counting) or a method based on open circuit voltage (OCV) estimation.

[0030] Display device 400 has a screen configured by a display unit such as, for example, an LCD (Liquid Crystal Display) or an organic EL (Electro-Luminescence) display. Predetermined information is displayed on the display unit of display device 400 in response to a control signal from control device 300. In this embodiment, display device 400 includes, for example, at least one of a display device provided in a position visible to a seated driver inside vehicle 1 (for example, in front of a front seat) and a display device of a mobile terminal such as a smartphone carried by a user.

[0031] Furthermore, the control device 300 estimates the degree of deterioration of the battery 100. In this embodiment, as an example, a "full charge capacity maintenance rate" defined as a percentage of the current full charge capacity relative to the full charge capacity (Ah) when the battery was new is calculated as the degree of deterioration of the battery 100, and the degree of deterioration is quantitatively evaluated. The higher the full charge capacity maintenance rate, the lower the degree of deterioration of the battery 100, and the lower the full charge capacity maintenance rate, the higher the degree of deterioration of the battery 100.

[0032] When it is time to update the degradation level, for example, after a predetermined time has elapsed since the execution of display control for displaying the previous degradation level, the control device 300 estimates the current value of the full charge capacity of the battery 100 using the amount of change in SOC and the integrated value of the charge and discharge current over the period up to that point. The control device 300 may calculate, as an estimated value of the degradation level, a full charge capacity maintenance rate calculated from the estimated current value of the full charge capacity and the full charge capacity when the battery was new.

[0033] Alternatively, the control device 300 may set a plurality of usage regions divided by the temperature and SOC of the battery 100, obtain a frequency distribution of use in each usage region during a period from the previous execution of the display control of the deterioration level until a certain time has elapsed, calculate a deterioration progress level in each region from the obtained frequency distribution, and calculate an estimated value of the deterioration level using the deterioration progress level and the amount of decrease in the full charge capacity maintenance rate calculated from the usage time in each region. Note that the method of estimating the deterioration level of the battery 100 is not limited to the above-described method, and any known technology may be applied.

[0034] The control device 300 causes information about the estimated degree of deterioration to be displayed on the display device 400. More specifically, the control device 300 causes the display device 400 to display the degree of deterioration using a numerical value and the number of segments.

[0035] The control device 300 displays, for example, the numerical value of the current full charge capacity maintenance rate as the degradation level. Furthermore, the control device 300 displays a number of segments corresponding to the current full charge capacity maintenance rate in a first manner. The segments are, for example, rectangular. The segments are, for example, rectangular images displayed on the screen. In this embodiment, the control device 300 displays the current degradation level using, for example, 10 segments. For example, when the battery 100 is in an initial state where it has not deteriorated, the control device 300 displays each of the 10 segments in the first manner. As the deterioration of the battery 100 progresses, the control device 300 reduces the number of segments displayed in the first manner. For example, the control device 300 reduces the number of segments displayed in the first manner by changing the segments displayed in the first manner (for example, the shaded areas) to the second manner (the open areas).

[0036] However, when the calculated deterioration degree is displayed, a sudden change in the displayed deterioration degree during a period in which the amount of change in the full charge capacity is relatively large in the early stages of use of the battery 100 may give the user a sense of discomfort.

[0037] Therefore, in this embodiment, the control device 300 causes the display device 400 to display the deterioration level using a numerical value and the number of segments, and causes the display device 400 to display the number of segments set in accordance with weighting according to the deterioration level. The weighting is set so that the timing at which the number of segments changes is the same when the secondary battery is in an initial state and when it is not in an initial state.

[0038] In this way, a set number of segments are displayed according to weighting corresponding to the degree of deterioration, so that, for example, by setting the weighting so that the change in the number of segments is gradual during a period in which the degree of deterioration changes suddenly, it is possible to prevent the user from feeling uncomfortable about the change in the degree of deterioration.

[0039] An example of processing executed by the ECU 100 will be described below with reference to Fig. 2. Fig. 2 is a flowchart showing an example of processing executed by the ECU 100.

[0040] In step (hereinafter, step will be abbreviated as S) 100, the control device 300 determines whether a display update condition is met. The display update condition may include, for example, a condition that a predetermined time has elapsed since the execution timing of display control that displayed information about the previous deterioration level, or a condition that a request to display the latest deterioration level has been received, for example, by accepting a user operation. If it is determined that the display update condition is met (YES in S100), the process proceeds to S102.

[0041] In S102, the control device 300 acquires the charge / discharge history. The control device 300 may acquire information corresponding to the charge / discharge history from the memory 302, or may acquire information corresponding to the charge / discharge history from the monitoring unit 200. The charge / discharge history includes information used to estimate the degree of deterioration. The charge / discharge history includes, for example, historical information on the temperature, current, and voltage of the battery 100 over a predetermined period. Thereafter, the process proceeds to S104.

[0042] In S104, control device 300 estimates the degree of deterioration of battery 100. The method for calculating the estimated value of the degree of deterioration of battery 100 is as described above, and therefore detailed description thereof will not be repeated. Thereafter, the process proceeds to S106.

[0043] In S106, the control device 300 acquires a threshold value for segment display. The threshold value is a threshold value for the degree of deterioration that changes the number of segments that are displayed in the first mode. In this embodiment, the multiple segments are made up of 10 rectangular segments. For example, 10 of the multiple segments are arranged horizontally. If there is no deterioration (initial state), the control device 300 displays the 10 segments in the first mode. The first mode includes, for example, a lit state or a state showing an area of ​​a predetermined color.

[0044] As the degree of degradation progresses, the control device 300 reduces the number of segments that are displayed in the first mode. The control device 300 displays all segments in the first mode while the degree of degradation changes from a no-degradation state (a state in which the degree of degradation (capacity maintenance rate) is 100%) to a first threshold value. While the degree of degradation changes from the first threshold value to a second threshold value, the control device 300 displays only the segments located at either the left or right end (the right end in this embodiment) in the second mode, and displays the other nine segments in the first mode. The second mode includes, for example, an off state or a state in which an area is displayed in a color different from the predetermined color described above.

[0045] The control device 300 displays the two right-hand segments in the second manner and the other eight segments in the first manner while the degradation level is changing from the second threshold to the third threshold. The control device 300 displays the three right-hand segments in the second manner and the other seven segments in the first manner while the degradation level is changing from the third threshold to the fourth threshold. The control device 300 displays the four right-hand segments in the second manner and the other six segments in the first manner while the degradation level is changing from the fourth threshold to the fifth threshold. The control device 300 displays the five right-hand segments in the second manner and the other five segments in the first manner while the degradation level is changing from the fifth threshold to the sixth threshold. The control device 300 displays the six right-hand segments in the second manner and the other four segments in the first manner while the degradation level is changing from the sixth threshold to the seventh threshold. While the degree of degradation is between the seventh threshold and the eighth threshold, the control device 300 displays the seven right-hand segments in the second mode and the other three segments in the first mode. While the degree of degradation is between the eighth threshold and the ninth threshold, the control device 300 displays the eight right-hand segments in the second mode and the other two segments in the first mode. When the degree of degradation falls below the ninth threshold, the control device 300 displays the nine right-hand segments in the second mode and the other one segment in the first mode.

[0046] The control device 300 acquires a threshold value according to the number of segments currently in the display state of the first aspect. For example, when 10 segments are in the display state of the first aspect, the control device 300 sets the first threshold value as the threshold value. Similarly, when 9 segments are in the display state of the first aspect, the control device 300 acquires the second threshold value as the threshold value, and when 8 segments are in the display state of the second aspect, the control device 300 acquires the third threshold value as the threshold value. In this way, the first to ninth threshold values ​​correspond to the number of segments in the display state of the first aspect, and the control device 300 sets the threshold values ​​using the number of segments in the display state of the first aspect.

[0047] The first to ninth thresholds are stored as predetermined values ​​in memory 302 of control device 300. The first to ninth thresholds are set in advance according to weighting based on the degree of deterioration. The weighting is set so that the timing at which the number of segments in the display state of the first mode changes is the same when battery 100 is in the initial state and when it is not in the initial state.

[0048] In this embodiment, for example, the first threshold is set to 80%, the second threshold is set to 70%, the third threshold is set to 60%, the fourth threshold is set to 50%, the fifth threshold is set to 40%, the sixth threshold is set to 30%, the seventh threshold is set to 20%, the eighth threshold is set to 10%, and the ninth threshold is set to 5%. Then, the process proceeds to S108.

[0049] At S108, control device 300 determines whether the degree of deterioration is smaller than the threshold value. The threshold value has been described above, and detailed description thereof will not be repeated. If it is determined that the degree of deterioration is smaller than the threshold value (YES at S108), the process proceeds to S110.

[0050] At S110, control device 300 determines whether a predetermined time has elapsed. Control device 300 determines that the predetermined time has elapsed if the duration of the current segment display state (the elapsed time from the most recent time when the number of segments in the display state of the first mode changed) exceeds the predetermined time. If it is determined that the predetermined time has elapsed (YES at S110), the process proceeds to S112.

[0051] At S112, control device 300 updates the segment display. More specifically, control device 300 reduces the number of segments in the display state of the first mode. Thereafter, the process proceeds to S112. If it is determined that the predetermined time has not elapsed (NO at S110), the process proceeds to S114. Also, if it is determined that the degree of deterioration is equal to or greater than the threshold value (NO at S108), the process proceeds to S114.

[0052] In S114, control device 300 updates the numerical indication of the deterioration degree to a numerical value corresponding to the estimated deterioration degree, and then the process ends.

[0053] An example of the operation of the control device 300 based on the above-described structure and flowchart will be described with reference to FIG. 3. FIG. 3 is a diagram showing an example of a display screen displayed on the display device 400. As shown in FIG. 3, the display device 400 includes a display unit 402 having a display screen. Ten rectangular segments 406 are arranged in the upper portion of the display unit 402, each abutting on its adjacent segments. The full charge capacity retention rate is displayed as the degree of deterioration in the lower portion of the display unit 402. FIG. 3 shows an example in which, of the ten segments, nine are in the first display state (the shaded area in FIG. 3) and one is in the second display state (the open area in FIG. 3). Furthermore, FIG. 3 shows an example in which the full charge capacity retention rate is displayed as a numerical value of 75%.

[0054] For example, when the vehicle 1 is used in a non-deteriorated state, each time the display update condition is met (YES in S100), the charge / discharge history is acquired (S102), and the degree of deterioration of the battery 100 is estimated (S104). Then, a threshold value corresponding to the current number of displayed segments is acquired (S106).

[0055] For example, as shown in FIG. 3, when nine of ten segments are in the display state in the first mode, the second threshold value (70%) is acquired as the threshold value.

[0056] If the estimated deterioration level (full charge capacity maintenance rate) is 75%, the deterioration level is equal to or greater than the threshold value (70%) (NO in S108), so only the numerical value is updated to 75%.

[0057] When nine of the ten segments are displayed in the first manner, the deterioration of battery 100 progresses and the degree of deterioration reaches 68%, which is determined to be less than the threshold value (70%) (YES in S108). At this time, if a predetermined period has passed since the nine segments were displayed in the first manner (YES in S110), the segment display is updated, and eight of the ten segments are displayed in the first manner, and the two segments on the right are displayed in the second manner.

[0058] In this way, the number of segments in the display state of the first mode decreases with the passage of a predetermined period of time as the deterioration of battery 100 progresses, so that when battery 100 is in the initial state, a sudden change in the number of segments in the display state of the first mode is suppressed even if the deterioration level changes suddenly. As a result, the user is prevented from feeling uncomfortable about the change in segment display.

[0059] As described above, in the battery system 4 according to the present embodiment, the segments are displayed in the first display state based on the thresholds set in accordance with the weighting corresponding to the deterioration level of the battery 100. In particular, by setting the weighting so that the change in the number of segments is gradual during the period (initial state) when the deterioration level changes suddenly (setting the first threshold and the second threshold so that the magnitude from 100% to the first threshold is greater than the magnitude from the first threshold to the second threshold), it is possible to prevent the user from feeling uncomfortable about the change in the deterioration level. Therefore, it is possible to provide a battery system that does not cause discomfort to the user with changes in the display of the deterioration level of the secondary battery.

[0060] Furthermore, the weighting is set so that the timing at which the number of segments changes is the same when the battery 100 is in an initial state and when it is not in an initial state, thereby preventing the user from feeling uncomfortable about the change in the deterioration level during periods when the deterioration level changes suddenly.

[0061] Furthermore, since the number of segments to be displayed changes based on a predetermined period, it is possible to prevent the user from feeling uncomfortable about the change in the deterioration level during a period in which the deterioration level changes suddenly.

[0062] Modifications will be described below.

[0063] In the above-described embodiment, it was explained that the number of segments in the display state of the first mode is reduced when the degree of deterioration becomes smaller than a threshold value and a predetermined time has elapsed, regardless of the number of segments in the display state of the first mode. However, the threshold value for determining the elapsed time may also be changed depending on the number of segments in the display state of the first mode.

[0064] Furthermore, in the above embodiment, the case where the plurality of segments is configured by ten segments has been described as an example, but the number of segments is not limited to ten.

[0065] Furthermore, in the above embodiment, the segments are described as having a rectangular shape, but they may have a predetermined shape, or multiple segments may have different shapes. Furthermore, the segments may have one shape as a whole (for example, a circular shape), and each segment may have a shape corresponding to the divided element (for example, a sector shape).

[0066] Furthermore, in the above-described embodiment, the case where multiple segments are arranged in a single horizontal row has been described as an example, but the segments may be arranged in two or more rows, or in one or more vertical rows.

[0067] Furthermore, in the above-described embodiment, the number of displayed segments is changed based on a predetermined period. However, for example, the number of displayed segments may be changed based on a predetermined degradation level in addition to or instead of the predetermined period. In this case, for example, the degradation level range in which 10 segments are displayed in the first mode may be set to be larger than the degradation level range in which another number of segments (e.g., 9 or less) are displayed in the first mode. In this way, it is possible to prevent the user from feeling uncomfortable about the change in degradation level during a period in which the degradation level changes suddenly.

[0068] The above-described modifications may be implemented in whole or in part in appropriate combination.

[0069] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0070] 1 vehicle, 2 drive system, 4 battery system, 20 power transmission gear, 30 drive wheel, 40 PCU, 50 SMR, 100 battery, 200 monitoring unit, 210 voltage detection section, 220 current detection section, 230 temperature detection section, 300 control device, 301 CPU, 302 memory, 400 display device, 402 display section, 406 segment.

Claims

1. a secondary battery mounted on the vehicle; a control device that calculates a deterioration level of the secondary battery; a display device that displays the degree of deterioration using a numerical value and the number of segments, The control device causes the display device to display a set number of the segments in accordance with weighting corresponding to the degree of deterioration.

2. The battery system according to claim 1 , wherein the weighting is set so that the timing at which the number of segments changes is the same when the secondary battery is in an initial state as when the secondary battery is not in the initial state.

3. 3. The battery system according to claim 1, wherein the control device changes the number of the segments to be displayed based on a predetermined period or a predetermined degree of deterioration.

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