control device

Abstract

Display the parameters indicating the battery status appropriately. [Solution] The control device is configured to estimate the battery capacity. The control device is configured to display parameters related to the estimated battery capacity on a display device. The control device is also configured to perform suppression control to limit the amount of usable energy in the battery when battery swelling is detected. When suppression control is being performed, the control device is configured to obtain the above parameters using the amount of usable energy in the battery that has been suppressed.

Description

Technical Field

[0005]

[0001] The present disclosure relates to a control device for controlling a display device.

Background Art

[0002] Japanese Unexamined Patent Application Publication No. 2003-164006 (Patent Document 1) discloses a display device for displaying the capacity of a vehicle battery. This display device has a plurality of segments (first display means) for stepwise displaying the remaining battery amount (charge amount) that changes over time with power consumption, and an Empty display lamp (second display means) that lights up when the remaining battery amount falls below a threshold value. In the Empty display lamp, the threshold value changes according to the degree of deterioration of the vehicle battery.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As the deterioration of the battery progresses, the battery may expand. And when the battery expands, the battery protection function may operate. Due to the operation of the battery protection function, the available battery capacity may change. Therefore, in a vehicle, if a parameter related to the battery capacity (for example, the capacity retention rate) is displayed without considering whether the battery protection function is operating, the user may misunderstand the state of the battery. Such problems are not described in Patent Document 1.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to appropriately display a parameter indicating the state of the battery.

Means for Solving the Problems

[0007] According to this disclosure, it will be possible to appropriately display parameters indicating the battery status. [Brief explanation of the drawing]

[0008] [Figure 1] This figure shows the configuration of a vehicle according to an embodiment of the present disclosure. [Figure 2] This is a flowchart showing the SOH update process according to this embodiment. [Figure 3] This flowchart shows the suppression control and display control according to this embodiment. [Modes for carrying out the invention]

[0009] Embodiments of this disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and their descriptions will not be repeated.

[0010] Figure 1 is a diagram showing the configuration of a vehicle according to this embodiment. Referring to Figure 1, the vehicle 1 comprises a vehicle body 10 and a battery pack 20. The vehicle body 10 is the part of the vehicle 1 other than the battery pack 20. The vehicle body 10 includes an MG (Motor Generator) 11a, an inverter 11b, an SMR (System Main Relay) 13, a DC charging relay 14a, a DC inlet 14b, an AC charger 15a, an AC inlet 15b, a DC / DC converter 16, an auxiliary battery 17, an HMI (Human Machine Interface) 18, a vehicle sensor 19, and a vehicle ECU 100. The battery pack 20 includes a battery 21, a monitoring unit 22, and a battery ECU 200. "ECU" means Electronic Control Unit. The battery ECU 200 corresponds to an example of a "control device" according to this disclosure. The vehicle 1 is configured to be able to run using the power output from the battery 21. Vehicle 1 is, for example, an electric vehicle (BEV). However, Vehicle 1 may be another electric vehicle (xEV).

[0011] The vehicle ECU 100 includes a processor 110 and a storage device 120. The battery ECU 200 includes a processor 210 and a storage device 220. Each storage device is configured to store the stored information. In addition to the program, each storage device stores various information used by the program. In each ECU, various controls are performed by the processor executing the program stored in the storage device.

[0012] The vehicle ECU 100 and the battery ECU 200 are configured to communicate with each other. The vehicle ECU 100 is configured to receive detection signals from various sensors included in the vehicle sensor 19 and to control various devices mounted on the vehicle body 10. The battery ECU 200 is configured to monitor the state of the battery 21 and send control commands related to the battery 21 to the vehicle ECU 100. The battery ECU 200 can control various devices mounted on the vehicle body 10 via the vehicle ECU 100. The vehicle ECU 100 controls the inverter 11b, SMR 13, DC charging relay 14a, AC charger 15a, DC / DC converter 16, and HMI 18, which are described below, either in response to a request from the battery ECU 200 or spontaneously.

[0013] The MG11a functions as a motor for driving. The inverter 11b drives the MG11a using power supplied from the battery 21. The MG11a converts the power into torque, which rotates the drive wheels of the vehicle 1. The MG11a also performs regenerative power generation, charging the battery 21. The SMR13 switches the connection / disconnection of the electrical circuit between the battery 21 and the inverter 11b.

[0014] Vehicle 1 is configured to enable external charging (charging of the battery 21 using power from outside the vehicle) while parked. In AC charging, with the SMR 13 connected and alternating current power input to the AC charger 15a via the AC inlet 15b from outside the vehicle, the vehicle ECU 100 controls the AC charger 15a. The AC charger 15a converts the alternating current power to direct current power according to control commands from the vehicle ECU 100 and outputs the direct current power to the battery 21. In DC charging, direct current power is input to the DC inlet 14b from outside the vehicle, and the vehicle ECU 100 connects the SMR 13 and the DC charging relay 14a. Vehicle 1 may also be configured to enable external power supply (power supply that outputs the battery 21 to the outside of the vehicle) while parked.

[0015] The DC / DC converter 16, for example, steps down the DC power from the battery 21 and outputs it to the auxiliary battery 17. The auxiliary battery 17 supplies power to drive the auxiliary equipment mounted on the vehicle 1. The battery ECU 200 may also receive power from the auxiliary battery 17.

[0016] The HMI18 includes an input device and a display device. The HMI18 may also include a touch panel display. The display device may be a meter panel.

[0017] The battery 21 is a secondary battery, such as a lithium-ion battery. Multiple secondary batteries may form a battery pack. In this embodiment, the battery 21 is constrained by a pair of end plates (restraining plates). The monitoring unit 22 includes a voltage sensor 22a for detecting the voltage of the battery 21, a current sensor 22b for detecting the current of the battery 21, a temperature sensor 22c for detecting the temperature of the battery 21, and a load sensor 22d for detecting the restraining load of the battery 21. The detection results of each sensor included in the monitoring unit 22 are output to the battery ECU 200. The battery ECU 200 is configured to acquire the State of Charge (SOC) of the battery 21 using the sensor detection values ​​output from the monitoring unit 22. SOC indicates the charge level. The charge level is, for example, the ratio of the current charge amount to the charge amount in a fully charged state, expressed as 0 to 100%.

[0018] The storage device 220 of the battery ECU 200 stores the State of Health (SOH) of the battery 21. In this embodiment, the capacity retention rate is used as the SOH. The capacity retention rate indicates the ratio of the current capacity to the initial capacity. The capacity retention rate of the battery 21 decreases as the degree of degradation of the battery 21 increases. The storage device 220 stores the estimated value and the displayed value of the SOH of the battery 21 separately. Initially, both the estimated value and the displayed value of the SOH (capacity retention rate) are set to 100%. However, the estimated SOH value indicates the gross value of the estimated SOH. On the other hand, the displayed SOH value indicates the net value of the SOH displayed on the display device. Details of these gross and net values ​​will be described later.

[0019] FIG. 2 is a flowchart showing the SOH update process by the battery ECU 200. The processing flow F1 shown in FIG. 2 is repeatedly executed by the battery ECU 200. "S" in the flowchart means a step.

[0020] Referring to FIG. 2, in the processing flow F1, at S11, the battery ECU 200 acquires the OCV (Open Circuit Voltage) of the battery 21 by the voltage sensor 22a. In the subsequent S12, the battery ECU 200 determines whether a predetermined condition (hereinafter referred to as the "start condition") is satisfied. If the start condition is not satisfied (NO at S12), the battery ECU 200 measures, at S13, the time until the start condition is satisfied. The time measured at S13 indicates the length of the vehicle parked period (a period during which neither driving, external charging, nor external power supply is performed). While the start condition is not satisfied, S12 and S13 are repeated at a predetermined calculation cycle.

[0021] In this embodiment, the above start condition is satisfied when the absolute value of the power storage change amount per unit time is equal to or greater than the first threshold value. The power storage change amount indicates the magnitude of the change in the amount of electric power stored in the battery 21. The power storage change amount, for example, indicates the change amount on the charging side as a positive value and the change amount on the discharging side as a negative value. Specifically, at S12, the battery ECU 200 acquires the current value of the battery 21 by the current sensor 22b and stores the obtained current value in the storage device 220 in association with the acquisition time. Then, the battery ECU 200 calculates the power storage change amount per unit time of the battery 21. The unit time is, for example, the above calculation cycle. When external charging is started in the vehicle 1, the power storage change amount becomes large on the positive side, and the above start condition is satisfied. When the vehicle 1 starts driving using the power of the battery 21, the power storage change amount becomes large on the negative side, and the above start condition is satisfied.

[0022] When the start condition is satisfied (YES in S12), the battery ECU 200 obtains the SOC of the battery 21 (hereinafter referred to as the "start SOC") in S14. For example, the storage device 220 stores in advance a map (OCV-SOC curve) showing the relationship between the OCV and SOC (gross value) of the battery 21 in the initial state (non-degraded). The battery ECU 200 refers to such a map and obtains the SOC (gross value) of the battery 21 from the OCV of the battery 21 obtained in S11. Then, the battery ECU 200 corrects the obtained SOC of the battery 21 using the temperature of the battery 21, and sets the corrected SOC as the start SOC. Further, the battery ECU 200 may further correct the SOC of the battery 21 using the amount of charge storage change and the vehicle parking period.

[0023] Subsequently, the battery ECU 200 integrates the amount of charge storage change in S15. Subsequently, the battery ECU 200 determines in S16 whether a predetermined condition (hereinafter referred to as the "end condition") is satisfied. If the end condition is not satisfied (NO in S16), the process returns to S15. While the end condition is not satisfied, S15 and S16 are repeated with the above-described operation cycle.

[0024] In this embodiment, the above end condition is satisfied when the absolute value of the amount of charge storage change per unit time becomes less than the second threshold value. The second threshold value is a value not exceeding the first threshold value. The unit time is, for example, the above operation cycle. The battery ECU 200 obtains the current value of the battery 21 by the current sensor 22b in S15, and stores the obtained current value in the storage device 220 in association with the acquisition time. The battery ECU 200 calculates the amount of charge storage change per unit time of the battery 21, and integrates the amount of charge storage change using the calculation result. During the period from when the start condition is satisfied until the end condition is satisfied (hereinafter referred to as the "target period"), the process of S15 is repeated, whereby the amount of charge storage change during the target period is obtained. For example, when the external charging being performed on the vehicle 1 is stopped, and when the traveling vehicle 1 stops, the end condition is satisfied.

[0025] If the termination condition is met (YES in S16), the battery ECU 200 acquires the OCV of battery 21 using the voltage sensor 22a in S17, and uses the obtained OCV to acquire the SOC of battery 21 (hereinafter referred to as "termination SOC"). The battery ECU 200, for example, refers to the aforementioned map (OCV-SOC curve) to acquire the SOC (gross value) of battery 21 from the OCV of battery 21. Then, the battery ECU 200 corrects the obtained SOC of battery 21 with the temperature of battery 21, and the corrected SOC is taken as the termination SOC.

[0026] In step S18, the battery ECU200 calculates the capacity C1 of the battery 21 according to the following formula (1). The capacity C1 corresponds to the amount of energy stored in the battery 21 when fully charged.

[0027] C1=100×dST / |SOC1-SOC2| …(1) In equation (1), the starting SOC is represented as "SOC1", the ending SOC as "SOC2", and the amount of charge change during the target period as "dST". |SOC1-SOC2| corresponds to the difference (absolute value) between the starting SOC and the ending SOC. The battery ECU 200 stores the calculated capacity C1 in the memory device 220, linked to the acquisition time.

[0028] Next, in S19, the battery ECU 200 calculates the capacity retention rate (SOH) of the battery 21 by dividing C1, which was calculated in S18, by C0, according to the formula (2) shown below.

[0029] SOH = 100 × C1 / C0 …(2) In equation (2), the capacity (gross value) of the battery 21 in its initial state (undegraded) is represented by "C0". C0 is pre-stored in, for example, the memory device 220. The battery ECU 200 stores the calculated state of health (SOH) in the memory device 220, linked to the acquisition time.

[0030] In the following S20, the battery ECU200 determines whether or not to update the SOH estimate. For example, the battery ECU200 decides to update the SOH estimate if |SOC1-SOC2| is equal to or greater than the reference value, and decides not to update the SOH estimate if |SOC1-SOC2| is less than the reference value. If |SOC1-SOC2| is equal to or greater than the reference value, it means that the SOH has been estimated with sufficiently high accuracy.

[0031] If it is determined that the SOH estimate should be updated (YES in S20), in S21, the battery ECU 200 sets the capacity retention rate calculated in the current processing routine (S19) as the latest SOH estimate in the storage device 220. In this case, the capacity C1 calculated in the current processing routine (S18) corresponds to the estimated capacity of the battery 21. In the following S22, the battery ECU 200 updates the SOH display value in the storage device 220. Specifically, the battery ECU 200 converts the SOH estimate (gross value) updated in S21 to a net value. The gross value, which indicates the characteristics of the battery 21 (capacity, SOC, etc.), is a numerical value that indicates the characteristics of the battery 21 alone. The net value, which indicates the characteristics of the battery 21, is a numerical value that indicates the characteristics of the battery 21 when it is installed in the vehicle 1. In this embodiment, the battery ECU 200 controls the SOC of the battery 21 within the SOC range from the lower limit of SOC to the upper limit of SOC (hereinafter referred to as the "practical SOC range"). The lower and upper limits of the State of Charge (SOC) are set, for example, to suppress the degradation of the battery 21. These values ​​are set using a gross value scale. For example, when the suppression control described later is not performed, the lower and upper limits of the SOC may be located at "10%" and "90%" on the gross value scale, respectively. However, the net value of the SOC is expressed with the lower limit of the SOC at "0%" and the upper limit of the SOC at "100%". The battery ECU 200 converts the gross value of the battery capacity to a net value based on the lower and upper limits of the SOC. The resulting estimated value (net value) of the battery 21 capacity represents the capacity in the practical SOC range, i.e., the usable energy amount of the battery 21. The battery ECU 200 calculates "SOH" by substituting the estimated value (net value) of the battery 21 capacity and the initial state capacity (net value) of the battery 21 into "C1" and "C0" in equation (2), respectively. The calculated SOH value (capacity retention rate) corresponds to the net value of the estimated SOH. In S22, the battery ECU200 sets the estimated SOH value (net value) to the SOH display value. This updates the SOH display value. Once the process in S22 is executed, the process returns to the initial S11. If the above |SOC1-SOC2| is less than the reference value (NO in S20), the process also returns to S11. However, in this case, the SOH display value is not updated.

[0032] Figure 3 is a flowchart showing the suppression control and display control performed by the battery ECU 200. The processing flow F2 shown in Figure 3 is repeatedly executed by the battery ECU 200. Processing flow F2 is executed in parallel with processing flow F1 shown in Figure 2.

[0033] Referring to Figure 3, in processing flow F2, the battery ECU 200 determines in S31 whether or not swelling of the battery 21 has been detected. The battery ECU 200 determines whether or not the battery 21 has swollen based, for example, on whether or not the restraining load detected by the load sensor 22d exceeds a predetermined value. The greater the amount of swelling of the battery 21, the greater the restraining load of the battery 21. The battery ECU 200 may also estimate the amount of swelling of the battery 21 based on the operation history of the battery 21.

[0034] If swelling of the battery 21 is detected (YES in S31), the battery ECU 200 performs suppression control in S32 to reduce the amount of usable energy in the battery 21. The battery ECU 200 may increase the lower limit of the SOC or decrease the upper limit of the SOC as the amount of swelling of the battery 21 increases, thereby narrowing the practical SOC range. By narrowing the practical SOC range of the battery 21, the amount of usable energy in the battery 21 is reduced. The battery ECU 200 may also make the practical SOC range during suppression control narrower than the practical SOC range when suppression control is not performed.

[0035] When the process in S32 is executed, the process proceeds to S33. If the battery 21 has not expanded (NO in S31), the process skips S32 and proceeds to S33. In S33, the battery ECU 200 determines whether the SOH display value has been updated. If the SOH display value has been updated by the process in S22 in Figure 2 (YES in S33), the battery ECU 200 controls the display device of the HMI 18 in S34 so that the updated SOH display value is displayed. When suppression control (S32 in Figure 3) is being executed, the battery ECU 200 calculates the net value of the battery 21 capacity and the net value of the estimated SOH value (capacity retention rate) based on the practical SOC range narrowed by the suppression control (S22 in Figure 2). Then, the battery ECU 200 sets the net value of the estimated SOH value as the SOH display value. In S34, the battery ECU 200 displays this SOH display value on the display device. Once the S34 process is executed, the process returns to the first step (S31). Also, if the SOH display value has not been updated (NO in S33), the S34 process is not executed, and the process returns to S31.

[0036] As described above, the control device (battery ECU200) according to this embodiment makes it possible to appropriately display parameters (SOH display value) indicating the state of the battery 21. The parameters related to the capacity of the battery 21 are not limited to the capacity retention rate and can be changed as appropriate. The parameters related to the capacity of the battery 21 may be the capacity of the battery 21 itself. In addition, the start and end conditions in the processing flow F1 shown in Figure 2 can also be changed as appropriate.

[0037] The configurations of the vehicle body and battery pack shown in Figure 1 can be modified as appropriate. The functions of the battery ECU 200 may be implemented in the vehicle ECU 100. The vehicle ECU 100 may estimate the degree of degradation of the battery 21 based on the information obtained from the battery ECU 200. The application of the control device is arbitrary. The control device may be applied to a stationary battery rather than an on-board battery.

[0038] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of the present invention is indicated by the claims rather than by the description of the embodiments above, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0039] 1 vehicle, 10 car bodies, 20 battery packs, 21 batteries, 200 battery ECUs.

Claims

[Claim 1] A control device for controlling a display device, The control device is configured to estimate the battery capacity and to display the estimated parameters related to the battery capacity on the display device. The control device is When swelling of the battery is detected, suppression control is performed to limit the amount of usable energy in the battery. A control device configured to acquire the parameter using the available energy of the suppressed battery when the suppression control is being performed.

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