control device

Abstract

The present invention provides a control device that can suppress a significant decrease in the capacity of the auxiliary battery while the vehicle is parked. [Solution] A control device for controlling the charging of a first battery while a vehicle is parked, comprising: a first control unit which is activated at a predetermined timing and stores the dark current of the first battery; a second control unit which estimates the consumed capacity of the first battery based on the average value of the dark current stored for each activation and the activation interval; a third control unit which estimates the current capacity of the first battery based on the consumed capacity and the full charge capacity of the first battery; a fourth control unit which predicts whether the remaining capacity of the first battery will fall below a first threshold by the next activation based on the average value of the consumed capacity estimated for each activation and the current capacity; and a fifth control unit which, if it is predicted that the remaining capacity will fall below the first threshold, causes the second battery to charge the first battery.

Description

【Technical Field】 【0001】 The present disclosure relates to a control device for controlling the charging of an accessory battery mounted on a vehicle. 【Background Art】 【0002】 Patent Document 1 discloses a charging control device that maintains the capacity (charge amount) of an accessory battery and prevents the accessory battery from overcharging. In this charging control device, when the capacity of the accessory battery decreases due to a dark current while the vehicle is parked, so-called pumping charging control is performed to charge the accessory battery with the power of a high-voltage battery that is the power supply source of the driving motor, thereby preventing the accessory battery from overcharging. 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 Japanese Patent Application Laid-Open No. 2020-137285 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 In the charging control device described in Patent Document 1, it is determined whether to perform pumping charging control based on the actually acquired capacity of the accessory battery, but this determination is only performed in a cycle of a predetermined charging scheduled time. Therefore, for example, when the dark current temporarily increases during the waiting for determination, the capacity of the accessory battery may significantly decrease and the deterioration may progress. Therefore, there is room for further study on the charging control method of the accessory battery of the vehicle. 【0005】 The present disclosure has been made in view of the above problems, and an object thereof is to provide a control device capable of suppressing a significant decrease in the capacity of an accessory battery while the vehicle is parked. 【Means for Solving the Problems】 【0006】 To solve the above problems, one aspect of the disclosed technology is a control device for controlling the charging of a first battery while a vehicle is parked, comprising: a first control unit which is activated at a predetermined timing and stores the dark current of the first battery; a second control unit which estimates the consumed capacity of the first battery based on the average value of the dark current stored for each activation and the activation interval; a third control unit which estimates the current capacity of the first battery based on the consumed capacity and the full charge capacity of the first battery; a fourth control unit which predicts whether the remaining capacity of the first battery will fall below a first threshold by the next activation based on the average value of the consumed capacity estimated for each activation and the current capacity; and a fifth control unit which, if it is predicted that the remaining capacity will fall below the first threshold, causes the second battery to charge the first battery. [Effects of the Invention] 【0007】 According to the control device described above, the need to charge the first battery (auxiliary battery) with the second battery (high-voltage battery) is determined in advance based on estimation and prediction, thereby preventing a significant decrease in the capacity of the first battery while the vehicle is parked. [Brief explanation of the drawing] 【0008】 [Figure 1] Functional block diagram of a control device and its peripheral parts according to one embodiment of the present disclosure. [Figure 2] Diagram illustrating the usage area of ​​the auxiliary battery. [Figure 3] A flowchart illustrating the processing procedure for auxiliary battery charging control (first example) performed by the control unit. [Figure 4] A flowchart illustrating the processing procedure for auxiliary battery charging control (second example) performed by the control unit. [Figure 5] An illustrative diagram showing what happens when the auxiliary battery's power consumption falls below its operating range. [Modes for carrying out the invention] 【0009】 The control device of this disclosure performs a pump-charge from the high-voltage battery to the auxiliary battery when it determines that the remaining capacity of the auxiliary battery in the near future will decrease to a level requiring charging, based on memory, learning, calculation, estimation, and prediction using the dark current obtained at the time of startup while parked. The embodiments of this disclosure will be described in detail below with reference to the drawings. 【0010】 <Embodiment> [composition] Figure 1 is a functional block diagram of a control device 122 and its peripheral parts according to one embodiment of the present disclosure. The functional block illustrated in Figure 1 includes a high-voltage battery 110, an auxiliary battery 120, a high-voltage DC-DC converter 130, an ECU 140, and a plurality of loads 150. In Figure 1, power lines through which power is exchanged are shown as solid lines, and signal lines through which request instructions are carried are shown as dashed lines. 【0011】 The configuration shown in Figure 1 can be installed in vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs), as an example. 【0012】 The high-voltage battery (second battery) 110 is a rechargeable secondary battery, such as a lithium-ion battery. The high-voltage battery 110 can supply the power it stores to multiple loads 150 and auxiliary batteries 120 via a high-voltage DC-DC converter 130 and multiple switches (SW) 142. The high-voltage battery 110 can also store power output by a generator (not shown), such as an alternator. In an electric vehicle, for example, the drive battery corresponds to the high-voltage battery 110. 【0013】 The auxiliary battery (first battery) 120 is a rechargeable secondary battery, such as a lithium iron phosphate (LFP) battery. The auxiliary battery 120 stores power output from the high-voltage battery 110 via the high-voltage DC-DC converter 130 and ECU 140, and supplies the power it has stored to the load 150 via the ECU 140. This auxiliary battery 120 includes a battery 121, a control device 122, and a switch (SW) 123. 【0014】 Battery 121 is, for example, a battery pack configured by connecting multiple battery cells in series and / or parallel. In the following explanation, in order to make the comparison with the high-voltage battery 110 easier to understand, battery 121 itself may be referred to as "auxiliary battery 120" as needed. 【0015】 The control device 122 is configured to manage the state of the auxiliary battery 120, including the charge and discharge control of the battery 121, and is typically a microcontroller. This control device 122 acquires and stores information on the dark current flowing from the auxiliary battery 120 to multiple loads 150 and the full charge capacity (first control unit), estimates the consumed capacity of the auxiliary battery 120 based on the dark current information (second control unit), estimates the current capacity of the auxiliary battery 120 based on the consumed capacity and the full charge capacity (third control unit), predicts the future remaining capacity of the auxiliary battery 120 based on the consumed capacity and the current capacity (fourth control unit), and requests charging of the auxiliary battery 120 based on the future remaining capacity of the auxiliary battery 120 (fifth control unit). In order to reduce power consumption while parked, this control device 122 can transition between a wake-up state in which all functions are activated and a sleep state in which some functions are disabled at predetermined timings. 【0016】 As shown in FIG. 2, for this auxiliary battery 120, a "usable area", which is the amount of electric power of the battery allowed to be used by discharge, is predetermined as the lower limit value of the battery capacity. This lower limit value is set to a value that can suppress, for example, the deterioration of the auxiliary battery 120 due to charge and discharge processing to the content required by the vehicle. 【0017】 The high-voltage DCDC converter 130 is provided between the high-voltage battery 110 and the ECU 140, and is a voltage converter that converts the voltage of the input high-voltage battery 110 into the voltages required for the auxiliary battery 120 and the load 150 and outputs them to each component via the ECU 140. For this high-voltage DCDC converter 130, for example, a step-down type DCDC converter that steps down the voltage of the high-voltage battery 110 and outputs it to the auxiliary battery 120 and the load 150 can be used. 【0018】 The ECU (Electronic Control Unit) 140 is a component (for example, a body domain controller (B-DC)) for comprehensively controlling the power transfer between the high-voltage battery 110, the auxiliary battery 120, and the plurality of loads 150. This ECU 140 includes a microcomputer 141 and a plurality of switches (SW) 142 that can switch the electrical connection state under the control of the microcomputer 141. 【0019】 The microcomputer 141 is communicably connected to the control device 122 of the auxiliary battery 120 and an in-vehicle network such as CAN. This microcomputer 141 performs control to charge the auxiliary battery 120 with the power of the high-voltage battery 110 in response to a charging request (described later) output from the control device 122. 【0020】 The plurality of loads 150 are in-vehicle devices that operate with the power supplied from the high-voltage battery 110 or the power supplied from the auxiliary battery 120 via the high-voltage DCDC converter 130. Note that the number of loads mounted on the vehicle is not limited to the number shown in FIG. 1. 【0021】 [Control] Next, with further reference to Figures 3 and 4, the control performed by the control device 122 according to one embodiment of the present disclosure will be described. Figure 3 is a flowchart illustrating the processing procedure of the charging control of the auxiliary battery 120 (first example) performed by the control device 122. Figure 4 is a flowchart illustrating the processing procedure of the charging control of the auxiliary battery 120 (second example) performed by the control device 122. 【0022】 (1) First example In the first example shown in Figure 3, the charging control of the auxiliary battery 120 starts when the vehicle's ignition is turned off (IG-OFF), such as when the vehicle is parked, and is repeated until the ignition is turned on (IG-ON). 【0023】 (Step S301) The control device 122 determines whether or not it is time to start up (wake up) in order to control the charging of the auxiliary battery 120 (battery 121). This start-up timing is as described above. 【0024】 If the control device 122 determines that it is time to start up (step S301, yes), it wakes up the stopped (sleep) function and proceeds to step S302. 【0025】 (Step S302) The control device 122 acquires the value of the dark current flowing from the auxiliary battery 120 to multiple loads 150 while the ignition is off. This dark current is the current consumed by, for example, functions related to electronic key authentication or a drive recorder that records while parked. The dark current can be acquired using a current sensor (not shown) provided on the auxiliary battery 120. The control device 122 then stores the acquired dark current value in a memory unit (not shown) and learns it. As an example of this learning, learning can be performed by averaging multiple dark current values ​​stored for each startup timing to improve the accuracy of the dark current. 【0026】 Once the control device 122 acquires, stores, and learns the value of the dark current of the auxiliary battery 120, the process proceeds to step S303. 【0027】 (Step S303) The control device 122 estimates the capacity consumed by the auxiliary battery 120 (consumption capacity) based on the average dark current of the auxiliary battery 120 learned in step S302 for each startup and the interval between startup timings. The consumption capacity Ccon [Ah] of the auxiliary battery 120 estimated during the elapsed time T [h] from the previous startup timing to the current startup timing can be calculated using the average dark current Iave [A] by the following equation 1. This calculated consumption capacity Ccon of the auxiliary battery 120 is sequentially stored in a memory unit or the like. Capacity consumption Ccon = Average dark current Iave × Elapsed time T …(Equation 1) 【0028】 Once the control device 122 estimates the power consumption capacity of the auxiliary battery 120, the process proceeds to step S304. 【0029】 (Step S304) The control device 122 estimates the current capacity of the auxiliary battery 120 based on the consumption capacity and full charge capacity of the auxiliary battery 120 estimated in step S303 above. The full charge capacity of the auxiliary battery 120 is defined as 100% of the initial (new) capacity of the auxiliary battery 120. The current capacity Ccur [Ah] of the auxiliary battery 120 can be calculated using the total consumption capacity Ctotal (=Σ consumption capacity Ccon) [Ah], which is the sum of the full charge capacity Cmax [Ah] and the consumption capacity Ccon stored so far, by the following equation 2. Current capacity Ccur = Fully charged capacity Cmax - Total consumption capacity Ctotal …(Equation 2) 【0030】 Once the control device 122 estimates the current capacity of the auxiliary battery 120, the process proceeds to step S305. 【0031】 (Step S305) The control device 122 determines whether the remaining capacity of the auxiliary battery 120 estimated at the next startup timing is less than a predetermined threshold value. This determination is to determine whether there is a possibility that the capacity of the auxiliary battery 120 will be used up to an area where the capacity deterioration may progress before the next startup timing arrives. Therefore, the lower limit value of the battery capacity of the auxiliary battery 120 described above is used as this threshold value. The specific estimation and determination are performed by comparing the value (Ccur - Ccon) obtained by subtracting the consumption capacity Ccon of the auxiliary battery 120 from the current capacity Ccur of the auxiliary battery 120 with the threshold value Th. 【0032】 When the control device 122 determines that the remaining capacity of the auxiliary battery 120 at the next startup timing is less than the threshold value (Ccur - Ccon < Th) (step S305, yes), the process proceeds to step S306. On the other hand, when the control device 122 determines that the remaining capacity of the auxiliary battery 120 at the next startup timing is greater than or equal to the threshold value (Ccur - Ccon ≧ Th) (step S305, no), the process returns to step S301. The capacity image of the auxiliary battery 120 at the time of this determination is shown in FIG. 5. 【0033】 (Step S306) The control device 122 performs charging (boost charging) of the auxiliary battery 120 using the power of the high-voltage battery 110. This charging is performed by the control device 122 transmitting a predetermined charging request to the microcomputer 141 of the ECU 140. The microcomputer 141 that has received the charging request controls (instructs) the high-voltage DCDC converter 130 to perform power transfer between the high-voltage battery 110 and the auxiliary battery 120. This charging may be performed until the auxiliary battery 120 is fully charged or until a predetermined power storage amount is reached. When the charging of the auxiliary battery 120 is performed, all or part of the consumption capacity of the auxiliary battery 120 stored in the storage unit or the like is deleted (cleared). 【0034】 When the control device 122 starts charging the auxiliary battery 120 with power from the high-voltage battery 110, the process returns to step S301. 【0035】 This first example of charging the auxiliary battery 120 allows for pump-charging from the high-voltage battery 110 to the auxiliary battery 120 if the remaining capacity of the auxiliary battery 120 is expected to exceed the usable range at the next periodic startup of the control device 122. This prevents a significant decrease in the capacity of the auxiliary battery 120 and suppresses the progression of its deterioration. 【0036】 (2) Second example In the second example shown in Figure 4, the charging control of the auxiliary battery 120 starts when the vehicle's ignition is turned off (IG-OFF), such as when the vehicle is parked, and is repeated until the ignition is turned on (IG-ON). 【0037】 (Step S401) The control device 122 determines whether or not it is time to start up (wake up) in order to control the charging of the auxiliary battery 120 (battery 121). This start-up timing can be arbitrarily set, such as a periodic timing that occurs at regular intervals (for example, every 10 minutes). 【0038】 If the control device 122 determines that it is time to start up (step S401, yes), it wakes up the stopped (sleep) function and proceeds to step S402. 【0039】 (Step S402) The control device 122 acquires the voltages (cell voltages) of all the battery cells that make up the battery 121 of the auxiliary battery 120. These cell voltages can be acquired using a voltage sensor or the like (not shown) provided on the auxiliary battery 120. These acquired cell voltages are stored in a memory unit or the like (not shown). 【0040】 Once the control device 122 has acquired all the battery cells of the multiple battery cells, the process proceeds to step S403. 【0041】 (Step S403) The control device 122 acquires the value of the dark current flowing from the auxiliary battery 120 to the multiple loads 150 while the ignition is off. The dark current is as described above. The control device 122 stores and learns the acquired dark current value in a memory unit or the like. This storage and learning is as described above. 【0042】 Once the control device 122 acquires, stores, and learns the value of the dark current of the auxiliary battery 120, the process proceeds to step S404. 【0043】 (Step S404) The control device 122 estimates the capacity consumed by the auxiliary battery 120 (consumed capacity) based on the average dark current value of the auxiliary battery 120 and the startup timing interval learned in step S403 above. The method for estimating the consumed capacity of the auxiliary battery 120 is as described above. 【0044】 Once the control device 122 estimates the power consumption capacity of the auxiliary battery 120, the process proceeds to step S405. 【0045】 (Step S405) The control device 122 estimates the current capacity of the auxiliary battery 120 based on the consumption capacity and full charge capacity of the auxiliary battery 120 estimated in step S404 above. The method for estimating the current capacity of the auxiliary battery 120 is as described above. 【0046】 Once the control device 122 estimates the current capacity of the auxiliary battery 120, the process proceeds to step S406. 【0047】 (Step S406) The control device 122 determines whether the estimated remaining capacity of the auxiliary battery 120 at the next startup timing will fall below a first threshold. This determination determines whether the capacity of the auxiliary battery 120 may be used up to a point where degradation is likely to progress before the next startup timing arrives. Therefore, the lower limit of the battery capacity of the auxiliary battery 120 described above is used as this first threshold. The specific estimation and determination are as described above. 【0048】 If the control device 122 determines that the remaining capacity of the auxiliary battery 120 at the next startup timing will be less than the first threshold (step S406, yes), the process proceeds to step S408. On the other hand, if the control device 122 determines that the remaining capacity of the auxiliary battery 120 at the next startup timing will be equal to or greater than the first threshold (step S406, no), the process proceeds to step S407. 【0049】 (Step S407) The control device 122 determines whether the minimum value (lower limit voltage) of the multiple cell voltages obtained in step S402 is below the second threshold. This determination is made to prevent a predetermined function from being realized due to a decrease in the full charge capacity caused by the deterioration of the auxiliary battery 120, by making a determination based only on the consumption capacity of the auxiliary battery 120. Therefore, the voltage (OCV) corresponding to the remaining capacity (SOC) necessary to realize the predetermined function is set as this second threshold. 【0050】 If the control device 122 determines that the minimum value of the cell voltage is less than or equal to the second threshold (step S407, yes), the process proceeds to step S408. On the other hand, if the control device 122 determines that the minimum value of the cell voltage exceeds the second threshold (step S407, no), the process returns to step S401. 【0051】 (Step S408) The control device 122 performs charging (pump charging) of the auxiliary battery 120 using the power from the high-voltage battery 110. The method of this charging is as described above. 【0052】 When the control device 122 starts charging the auxiliary battery 120 with power from the high-voltage battery 110, the process returns to step S401. 【0053】 In this second example of the auxiliary battery 120 charging process, even if the remaining capacity of the auxiliary battery 120 is not expected to exceed the usable range at the next periodic startup of the control device 122, if there is a risk that the predetermined functions may not be realized, a power transfer charge from the high-voltage battery 110 to the auxiliary battery 120 can be performed. This makes it possible to avoid situations such as the inability to satisfactorily perform redundant functions due to insufficient backup power. 【0054】 (3) Application Examples While the control device 122 is in sleep mode, a large amount of quiescent current may flow as part of the parking service. If a large quiescent current flows compared to the average quiescent current, the remaining capacity of the auxiliary battery 120 will decrease significantly. 【0055】 Therefore, in such cases, in steps S301 and S401 described above, the control device 122 may be activated not only at timings that occur at regular time intervals, but also at timings when it is detected that the dark current is flowing above a certain value (third threshold). If the control device 122 is activated at the timing when it is detected that the dark current is flowing above a certain value, the control device 122 needs to appropriately estimate the consumption capacity and current capacity of the auxiliary battery 120 based on the irregular time difference between the previous activation and the current activation. 【0056】 <Effects and Actions> As described above, according to the control device 122 of one embodiment of the present disclosure, the consumption capacity of the auxiliary battery 120 is estimated based on the dark current flowing out of the auxiliary battery 120 while parked, the current capacity of the auxiliary battery 120 is estimated based on this consumption capacity, and if it is determined based on this current capacity that the remaining capacity of the auxiliary battery 120 is likely to fall below a lower limit in the near future, the auxiliary battery 120 is charged with the high-voltage battery 110. 【0057】 This charging control prevents a significant decrease in the capacity of the auxiliary battery 120 while the vehicle is parked (ignition off). Therefore, it is possible to suppress the progression of deterioration of the auxiliary battery 120. 【0058】 Although one embodiment of the present disclosure has been described above, the present disclosure can be interpreted not only as the control device described above, but also as a method executed by a control device equipped with a processor and memory, a program for that method, a computer-readable non-temporary recording medium storing that program, or a vehicle equipped with the control device. [Industrial applicability] 【0059】 The control device of this disclosure can be used in vehicles equipped with a high-voltage battery and an auxiliary battery, etc. [Explanation of Symbols] 【0060】 110 High-voltage battery 120 Auxiliary Battery 121 Battery 122 Control device 123 Switch (SW) 130 High-voltage DC-DC converter 140 ECU 141 Microcontroller 142 Switches (SW) 150 load

Claims

[Claim 1] A control device for controlling the charging of a first battery while a vehicle is parked, A first control unit that is activated at a predetermined timing and stores the dark current of the first battery, A second control unit estimates the power consumption capacity consumed by the first battery based on the average value of the dark current stored for each startup and the interval between startups. A third control unit estimates the current capacity of the first battery based on the consumption capacity and the full charge capacity of the first battery, A fourth control unit predicts whether the remaining capacity of the first battery will fall below a first threshold by the next startup, based on the average value of the consumption capacity estimated for each startup and the current capacity. The system includes a fifth control unit which, when it is predicted that the remaining capacity will fall below the first threshold, causes the second battery to charge the first battery, Control device. [Claim 2] The first control unit further acquires the voltage of each of the multiple battery cells constituting the first battery and stores the minimum value of the voltage. The fourth control unit further determines whether the minimum value of the voltage is less than or equal to the second threshold, The fifth control unit, if it is determined that the minimum voltage is less than or equal to the second threshold, even if it is predicted that the remaining capacity will not fall below the first threshold, will cause the second battery to charge the first battery. The control device according to claim 1. [Claim 3] The predetermined timing includes timings that occur at regular time intervals and timings when the dark current exceeds a third threshold. The control device according to claim 1 or 2.

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