CONTROL DEVICE

Abstract

A control device configured to control an auxiliary battery (130) attached to a vehicle comprises: a first processing unit that sets a permissible charging current of the auxiliary battery (130) based on a state of the vehicle and a state of the auxiliary battery (130); and a second processing unit that controls the charging of the auxiliary battery (130) based on the permissible charging current.

Description

BACKGROUND OF THE INVENTION 1. Field of the invention

[0001] The present disclosure relates to a control device that controls a battery mounted in a vehicle. 2. Description of the related prior art

[0002] Unexamined Japanese patent application disclosure no. 2021-068637 (JP 2021-068637 A) discloses a charging control device that prevents metallic lithium from depositing on the negative electrode of a lithium-ion battery when a battery consisting of a lithium-ion battery is being charged. JP 2021-068637 A describes that this control device calculates an allowable charging current based on a state (current, temperature, or state of charge) of the battery and charges the battery based on this allowable charging current. BRIEF SUMMARY OF THE INVENTION

[0003] If the permissible charging current of the battery is calculated solely based on the battery's state of charge (current, temperature, or state of charge), there is a possibility that the actual charging current flowing through the battery will exceed the permissible current due to fluctuations in a load connected to the battery (changes in power consumption). If the battery's charging current exceeds the permissible current, lithium deposition will occur.

[0004] The present disclosure provides a control device capable of preventing the formation of lithium deposits in a battery, even when a load connected to the battery fluctuates.

[0005] One aspect of the present disclosure relates to a control device configured to control an auxiliary battery mounted in a vehicle. The control device comprises: a first processing unit that sets a permissible charging current of the auxiliary battery based on a state of the vehicle and a state of the auxiliary battery; and a second processing unit that controls the charging of the auxiliary battery based on the permissible charging current.

[0006] The control device according to the point of view of the present disclosure may comprise: a third processing unit that reduces and resets the permissible charging current when an actual charging current flowing through the auxiliary battery exceeds the permissible charging current; and a fourth processing unit that detects that an abnormality in the charging control has occurred when the actual charging current continuously exceeds the reset permissible charging current for a predetermined time.

[0007] In the control device according to the present disclosure, the condition of the auxiliary battery can include its temperature and its capacity maintenance rate. The first processing unit can adjust the permissible charging current depending on the auxiliary battery's temperature and its capacity maintenance rate.

[0008] In the control device according to the present disclosure, the vehicle's state can include whether the vehicle is parked or not. The first processing unit can adjust the permissible charging current in a case other than when the vehicle is parked so that it is lower than when the vehicle is parked.

[0009] The control devices of this aspect adjust the permissible charging current depending on the condition of the vehicle and the condition of the auxiliary battery, so that lithium deposits in the battery can be prevented even with fluctuating loads connected to the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Features, advantages and technical and industrial significance of embodiments of the invention are described below with reference to the accompanying drawings, in which the same symbols denote the same elements and in which: Fig. Figure 1 is a schematic configuration diagram of a load and a power supply system including a control device according to an embodiment of the present disclosure; Fig. Figure 2 is a process flow diagram of the control of the charging of the auxiliary battery, which is carried out by the control device; Fig. Figure 3 is an example of a two-dimensional map for deriving a permissible charging current; and Fig. Figure 4 is a time diagram illustrating the change of individual states during the control of the charging of the auxiliary battery. DETAILED DESCRIPTION OF THE EXECUTION EXAMPLES

[0011] A control device of the present disclosure prevents lithium deposits caused by a charging current generated at the time of load fluctuations according to a vehicle's condition by setting a permissible charging current not only on the basis of an auxiliary battery's condition but also on the basis of the vehicle's condition.

[0012] An embodiment of the present disclosure is described in detail below with reference to the drawings. Example configuration

[0013] Fig. Figure 1 is a diagram showing a schematic configuration of a power supply system 100, which includes a control device according to an embodiment of the present disclosure and a load 200 that is supplied with electrical energy by the power supply system 100. The in Fig. The power supply system 100 shown in Figure 1 comprises a high-voltage battery 110, a DC-DC converter 120, an auxiliary battery 130, and an ECU 140. Fig. 1 is a line through which electrical energy flows, indicated by the thick line, and a line through which a detection signal, a control signal and the like flows, indicated by the dashed line.

[0014] The in Fig. The configuration shown can, for example, be installed in an electrified vehicle, such as a battery electric vehicle (BEV).

[0015] The high-voltage battery 110, for example, is a secondary battery configured to be charged and discharged, like a lithium-ion battery. The high-voltage battery 110 can supply the electrical energy stored in it to the auxiliary battery 130 and the load 200 via the DC-DC converter 120. Furthermore, the high-voltage battery 110 can store electrical energy supplied by a power generator (not shown), such as an alternator. In an electrified vehicle, the high-voltage battery 110 corresponds, for example, to a traction battery.

[0016] The DC-DC converter 120 is an electrical power converter installed between the high-voltage battery 110 and the auxiliary battery 130. It converts the electrical power received as input from the high-voltage battery 110 into electrical power with a voltage required for the auxiliary battery 130 or the load 200 to deliver the electrical power. For example, a DC-DC step-down converter can be used as the DC-DC converter 120, which steps down the voltage of the high-voltage battery 110 to output the voltage to the auxiliary battery 130 or the load 200.

[0017] The auxiliary battery 130 is, for example, a secondary battery configured to be charged and discharged, such as a lithium-ion battery. The auxiliary battery (Aux.-LiB) 130 stores the electrical power delivered by the high-voltage battery 110 via the DC-DC converter 120 or supplies the stored electrical power to the load 200. In this embodiment, the auxiliary battery 130 is configured as a control unit comprising a battery 131, a switch (SW) 132, a sensor 133, and a control unit 134.

[0018] Battery 131, for example, is a composite battery configured by connecting several battery cells in series and / or parallel. Switch 132 is a switching element capable of switching an electrical connection state (conducting / disconnecting) between battery 131 and each of the DC-DC converters 120 and the load 200. The connection state of switch 132 is switched by the control unit 134. A solid-state relay or similar device is used as switch 132. Sensor 133 is a device that detects a state (voltage, current, temperature, etc.) of battery 131. A voltage sensor, current sensor, temperature sensor, or similar device is used as sensor 133. The control unit 134 is a configuration designed to monitor and control the state of the auxiliary battery 130 and is, for example, a microcontroller (an arithmetic microcontroller) or at least a processor.A single processor of the control unit 134 can perform the first four processes described below. Alternatively, multiple processors of the processing unit 134 can each perform the first four processes. For example, the processing unit 134 detects the state of the battery 131 from the sensor 133 and sets an input current (hereinafter referred to as the "permissible charging current of the auxiliary battery 130") that is permissible when the battery 131 is being charged, based on the state of the battery 131 and a state of the vehicle detected by a predetermined in-vehicle device or the like (not shown).

[0019] The ECU 140 is an electronic control unit that manages the electrical power transfer between the high-voltage battery 110 and the auxiliary battery 130. The ECU 140 includes a control unit 141, which controls the DC-DC converter 120 in the configuration. The control unit 141 is, for example, a microcontroller (an arithmetic microcontroller) or at least a processor. The processing unit 141, for example, performs processing to control an output voltage of the DC-DC converter 120 according to a permissible charging current, which is provided as a signal by the control unit 134 of the auxiliary battery 130. The control unit 141 of the ECU 140 and the control unit 134 of the auxiliary battery 130 are interconnected so that they can communicate with each other via an in-vehicle network such as a Controller Area Network (CAN) or a direct line.

[0020] Load 200 is an onboard piece of equipment (an auxiliary load) that is powered by electrical power supplied by the high-voltage battery 110 via the DC-DC converter 120 and / or by the auxiliary battery 130. The number of loads 200 supplied with electrical energy by the power supply system 100 is not limited to one. Furthermore, the connection mode between the power supply system 100 and the load 200 is not limited to the one described in the diagram. Fig. The mode shown in 1 is limited, and it is also possible to use a mode in which the load 200 is connected to the power supply system 100 (the DC-DC converter 120 or the auxiliary battery 130) via one or more switches, an ECU or the like.

[0021] The control device according to an embodiment of the present disclosure is a configuration comprising the control unit 134 of the auxiliary battery 130 and the control unit 141 of the ECU 140. It should be noted that Fig. Figure 1 shows an example where the control unit 134 and the control unit 141 are configured as separate elements, but the control unit 134 and the control unit 141 can be configured integrally. steering

[0022] Next, with reference to Fig. 2 the control carried out by the control device according to an embodiment of the present disclosure is described. Fig. Figure 2 is a flowchart illustrating a process flow of controlling the charging of the auxiliary battery, which is carried out by the control unit 134 of the auxiliary battery 130 and the control unit 141 of the control device 140 to configure the control device.

[0023] The in Fig. 2 The control of the auxiliary battery charging shown is started when a charging request for the auxiliary battery 130 is generated with the electrical power of the high voltage battery 110, such as a power transfer charging. Step S201

[0024] The control unit 134 of the auxiliary battery 130 detects the vehicle's state (the vehicle's power supply status) and the battery's state 131. Specifically, the control unit 134 detects whether the vehicle is parked or not, as well as the vehicle's state from predetermined internal vehicle devices (not shown). Furthermore, the control unit 134 detects the battery 131's temperature as the battery's state from sensor 133.

[0025] When the vehicle's parking status and the battery temperature 131 are detected by the control unit 134, the procedure continues with step S202. Step S202

[0026] The control unit 134 of the auxiliary battery 130 sets a permissible charging current for the auxiliary battery 130 based on the vehicle's condition and the condition of the battery 131 (a first process). Specifically, the control unit 134 sets the permissible charging current of the auxiliary battery 130 depending on whether the vehicle is parked or not, the temperature of the battery 131, and a capacity maintenance rate (an estimated value) of the battery 131. In this embodiment, the permissible charging current is defined as an upper limit of the current that is fed into the battery 131 and can lead to lithium deposits.Furthermore, the capacity maintenance rate of battery 131 is a value that indicates the ratio between the full charge capacity of battery 131 in the current auxiliary battery 130, which has deteriorated over time, and the full charge capacity (100%) of battery 131 at the time when the auxiliary battery 130 was new. It should be noted that the full charge capacity can be calculated using a known method (mapping of elapsed time, current integration method, etc.).

[0027] An example of a method for deriving the permissible charging current to be set is a method for using a two-dimensional map that is determined in advance on the basis of a correspondence between the temperature of battery 131 and the capacity maintenance rate of battery 131. Fig. Figure 3 shows an example of the two-dimensional map for deriving the permissible charging current of the auxiliary battery 130.

[0028] Fig. Figure 3 shows an example where two-dimensional maps with different permissible charging current values ​​are created for two cases: one where the vehicle's state (the state of the vehicle's power supply) is parked, and one where the vehicle's state (the state of the vehicle's power supply) is other than parked. In this case, the permissible charging current of the two-dimensional map is set to be lower (one value lower than the standard value) than the permissible charging current (a standard value) of the two-dimensional map when the vehicle is parked. The reason for this is as follows: In a state other than the parked state (e.g., while driving), where the load can fluctuate more than in the parked state (e.g.,(during electrical energy transmission), the charging current to the auxiliary battery 130 is also increased when the operation of the load 200 is switched off. This change in the charging current is caused by the fact that the amount of current consumed by the load 200 when it is switched on is used to charge the auxiliary battery 130 when it is switched off (see . Fig. 4) To prevent the charging current, which increases when the operation of load 200 is switched off, from reaching a lithium deposition occurrence region, the permissible charging current to be set for the auxiliary battery 130 is reduced when the vehicle is in a state other than that of being parked.

[0029] When the permissible charging current of the auxiliary battery 130 is set, the control unit 134 notifies the control unit 141 of the control device 140 of the information regarding the permissible charging current. In response to this notification, the control unit 141 adjusts the output voltage of the DC-DC converter (DDC) 120 so that the charging current of the auxiliary battery 130 does not exceed the permissible charging current, and controls the current at the time the auxiliary battery 130 is supplied with electrical energy from the high-voltage battery 110 (a second operation).

[0030] When the control unit 134 determines the permissible charging current of the auxiliary battery 130 based on the condition of the vehicle and the condition of the battery 131, and the control unit 141 controls the DC-DC converter 120 according to the permissible charging current, the procedure continues with step S203. Step S203

[0031] The control unit 134 of the auxiliary battery 130 determines whether the actual charging current flowing through the auxiliary battery 130 (hereinafter referred to as the "actual charging current") exceeds the permissible charging current. This determination serves to verify whether the charging control of the auxiliary battery 130, which is based on the permissible charging current, is operating normally.

[0032] If the control unit 134 determines that the actual charging current of the auxiliary battery 130 exceeds the permissible charging current (step S203, YES), the procedure continues with step S204. However, if the control unit 134 determines that the actual charging current of the auxiliary battery 130 does not exceed the permissible charging current (step S203, NO), the procedure continues with step S201. Step S204

[0033] The control unit 134 of the auxiliary battery 130 sets the permissible charging current of the auxiliary battery 130 to "0" (zero) (a third operation). This setting is made to recheck whether the charging control of the auxiliary battery 130 is functioning normally after the supply to the auxiliary battery 130 by the high-voltage battery 110 was temporarily interrupted.

[0034] When the permissible charging current of the auxiliary battery 130 is set to “0”, the control unit 134 communicates the permissible charging current information to the control unit 141 of the ECU 140. In response to this communication, the control unit 141 reduces the output voltage of the DC-DC converter (DDC) 120 and stops the current supply from the high-voltage battery 110 to the auxiliary battery 130 (the second operation).

[0035] When the control unit 134 sets the permissible charging current of the auxiliary battery 130 to “0” and the control unit 141 controls the DC-DC converter 120 according to the permissible charging current, the procedure proceeds to step S205. Step S205

[0036] The control unit 134 of the auxiliary battery 130 determines whether the actual charging current of the auxiliary battery 130 continuously exceeds the permissible charging current for a predetermined time. In other words, the control unit 134 determines whether the charging current continues to flow to the auxiliary battery 130 for a predetermined time even after the permissible charging current has been set to "0". This determination is made to define that an anomaly has occurred in the charging control of the auxiliary battery 130 based on the permissible charging current. Therefore, the predetermined time is set to a duration sufficient to define that an anomaly has occurred in the charging control.

[0037] If the control unit 134 determines that the actual charging current of the auxiliary battery 130 continuously exceeds the permissible charging current for a predetermined time (step S205, YES), the procedure continues with step S207. However, if the control unit 134 determines that the actual charging current of the auxiliary battery 130 does not continuously exceed the permissible charging current for a predetermined time (step S205, NO), the procedure continues with step S206. Step S206

[0038] The control unit 134 of the auxiliary battery 130 determines whether the actual charging current of the auxiliary battery 130 has converged to or below the permissible charging current. In other words, the control unit 134 determines whether the charging current of the auxiliary battery 130 is also reduced to zero in response to the setting of the permissible charging current to "0".

[0039] If the control unit 134 determines that the actual charging current of the auxiliary battery 130 has converged to the permissible charging current or less (step S206, YES), the procedure continues with step S201. If, in the meantime, the control unit 134 determines that the actual charging current of the auxiliary battery 130 has not converged to the permissible charging current or less (step S206, NO), the procedure continues with step S203. Step S207

[0040] The auxiliary battery 130's control unit 134 detects that an anomaly (limit violation anomaly) has occurred in the charging control of the auxiliary battery 130 based on the permissible charging current (a fourth operation). Examples of the cause of the anomaly include a setting anomaly of the permissible charging current in the control unit 134, a communication anomaly between the control unit 134 and the control unit 141, a command value anomaly to the DC-DC converter 120 by the control unit 141, an operating anomaly of the DC-DC converter 120 based on the command value, and the like.

[0041] It should be noted that if an anomaly in the charging control is detected, it is desirable to notify a driver or the like of the occurrence of the anomaly in the charging control via a measuring device, an information display or the like of the vehicle.

[0042] If the control unit 134 detects that an anomaly (limit violation anomaly) has occurred in the charging control of the auxiliary battery 130 based on the permissible charging current, this charging control of the auxiliary battery is terminated. Actions and effects

[0043] As described above, in the control device according to an embodiment of the present disclosure, the permissible charging current of the auxiliary battery 130 is set based on the condition of the vehicle and the condition of the auxiliary battery 130, and the charging of the auxiliary battery 130 is controlled based on the set permissible charging current. If the actual charging current of the auxiliary battery 130 then exceeds the permissible charging current, the permissible charging current is reduced and reset, and if the actual charging current continuously exceeds the reset permissible charging current for a predetermined time, it is detected that an anomaly has occurred in the charging control of the auxiliary battery 130.

[0044] With this control system, the permissible charging current can be set not only on the basis of the condition of the auxiliary battery 130, but also on the basis of the vehicle condition, so that the occurrence of lithium deposits in the auxiliary battery 130 can be prevented even if the load 200 connected to the auxiliary battery 130 fluctuates differently depending on the vehicle condition.

[0045] An embodiment of the present disclosure has been described above, but the present disclosure can be regarded not only as the control device mentioned above, but also as a method to be executed by a control device having a processor and a memory, a program for the method, a computer-readable, non-transitory recording medium in which the program is stored, a vehicle in which the control device is mounted, or the like.

[0046] The control device of the present disclosure can, for example, be used for a vehicle with a high-voltage battery and an auxiliary battery. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2021-068637 A

[0002]

Claims

A control device configured to control an auxiliary battery (130) fitted to a vehicle, the control device comprising: a first processing unit that sets a permissible charging current of the auxiliary battery (130) based on a state of the vehicle and a state of the auxiliary battery (130); and a second processing unit that controls charging of the auxiliary battery (130) based on the permissible charging current. Control device according to claim 1, further comprising: a third processing unit that reduces and resets the permissible charging current when an actual charging current actually flowing through the auxiliary battery (130) exceeds the permissible charging current; and a fourth processing unit that determines that an anomaly has occurred in a charging control when the actual charging current continuously exceeds the reset permissible charging current for a predetermined time. Control device according to claim 1 or 2, wherein: the state of the auxiliary battery (130) comprises a temperature of the auxiliary battery and a capacity maintenance rate of the auxiliary battery; and the first processing unit sets the permissible charging current according to the temperature of the auxiliary battery (130) and the capacity maintenance rate of the auxiliary battery (130). Control device according to claim 3, wherein: the state of the vehicle includes whether the vehicle is parked or not; and the first processing unit, in a case different from a case where the vehicle is parked, adjusts the permissible charging current to be smaller than in a case where the vehicle is parked.

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