Method for control dual batteries in hybrid electric vehicle

Abstract

A method of operation for a processor controlling the charging of a dual battery installed in a hybrid vehicle, comprising: a step of opening a relay located between a first battery for load and a second battery for starting when a start attempt of the hybrid vehicle is detected, and checking whether the start is successful; a step of closing the relay so that the first battery and the second battery are connected in parallel when the start fails; and a step of entering the second battery into a charging mode and charging the second battery when a retry of the start attempt of the hybrid vehicle is successful.

Description

Technology Field

[0001] The present disclosure relates to dual battery control technology for a vehicle. Background Technology

[0002] Electric vehicles are classified into hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), and pure electric vehicles (EV) depending on the extent to which electric motors and batteries are involved in the existing internal combustion engine.

[0003] Pure electric vehicles are vehicles that run solely on electric energy, while hybrid and plug-in hybrid vehicles are vehicles that combine an internal combustion engine with an electric motor.

[0004] Recently, low-cost hybrid vehicles are being developed to minimize production costs. Low-cost hybrid vehicles can be implemented by eliminating components such as the Mild Hybrid Starter and Generator (MHSG) and the Low Voltage DC-DC Converter (LDC). However, in such cases, since the MHSG is absent, the vehicle must be started using a 12V starter when the EV mode is deactivated while driving. This causes a voltage drop, which may result in the reset of various controllers or the flickering of lamps. Therefore, battery control technology is required to stabilize the system of low-cost hybrid vehicles. The problem to be solved

[0005] The present disclosure relates to a method for controlling dual batteries installed in a hybrid vehicle by controlling relays of dual batteries according to vehicle state and battery state. means of solving the problem

[0006] According to one embodiment, a method of operation of a processor for controlling a dual battery installed in a hybrid vehicle comprises: a step of opening a relay located between a first battery for load and a second battery for start when a start attempt of the hybrid vehicle is detected, and checking whether the start is successful; a step of closing the relay so that the first battery and the second battery are connected in parallel when the start fails; and a step of charging the second battery by putting it into a charging mode when a retry attempt to start the hybrid vehicle is successful.

[0007] The above operation method may further include the step of closing the relay to charge the second battery when the start is successful, and opening the relay when the second battery is charged to a discharge amount greater than that of the start.

[0008] The above operation method may further include the step of transmitting a battery check message to a linked display or terminal if the attempt to restart the hybrid vehicle fails.

[0009] The first battery is connected to an electronic generator, and the second battery is connected to a starter that attempts to start, and the first battery and the second battery can be connected or disconnected through the relay.

[0010] The step of charging the second battery may restrict the change to a driving mode that stops the power generation of the electronic generator when the second battery is in a charging mode.

[0011] The step of charging the second battery may end the charging of the second battery and open the relay when the accumulated charging time reaches the full charge reference time.

[0012] The step of charging the second battery may involve setting a target charging voltage based on the status information of the second battery, and if the target charging voltage is not satisfied at the full charge reference time, a battery check message may be transmitted to a linked display or terminal.

[0013] The above operation method may further include the step of opening the relay when the charge state of the first battery is higher than the first threshold when the engine of the hybrid vehicle is turned off, and closing the relay when the charge state of the first battery is lower than the first threshold to charge the first battery.

[0014] The above operation method may further include the step of opening the relay to stably maintain the voltage of the first battery when EV mode release is detected due to a change in the driving mode of the hybrid vehicle. Effects of the invention

[0015] According to an embodiment, by controlling the relay of the dual battery, it is possible to prevent electrical load fluctuations caused by voltage drop that may occur when changing the vehicle's driving mode while ensuring the vehicle's starting performance. Brief explanation of the drawing

[0016] FIG. 1 is a configuration diagram of a hybrid vehicle including a dual battery according to one embodiment. FIG. 2 is a flowchart illustrating a relay control method according to a first battery state in a vehicle's engine off state according to one embodiment. FIG. 3 is a flowchart illustrating a relay control method according to one embodiment of a vehicle start. FIG. 4 is a flowchart illustrating a control method for a charging mode of a second battery according to one embodiment. Specific details for implementing the invention

[0017] Embodiments of the present disclosure are described below with reference to the attached drawings so that those skilled in the art can easily implement them. However, the present disclosure may be embodied in various different forms and is not limited to the embodiments described herein. Furthermore, in order to clearly explain the present disclosure in the drawings, parts unrelated to the explanation have been omitted, and similar parts throughout the specification are denoted by similar reference numerals.

[0018] In the specification, when a part is described as "including" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. Devices constituting a network may be implemented in hardware, software, or a combination of hardware and software.

[0019] Additionally, terms such as "...part," "...unit," and "...control module" described in the specification refer to a unit that processes at least one function or operation, and this may be implemented in hardware, software, or a combination of hardware and software.

[0020] The devices described in this disclosure are composed of hardware including at least one processor, a memory device, a communication device, etc., and a program that is executed in combination with the hardware is stored in a designated location. The hardware has a configuration and performance capable of executing the method of this disclosure. The program includes instructions that implement the method of operation of this disclosure described with reference to the drawings, and executes this disclosure in combination with hardware such as a processor and a memory device.

[0021] In the present disclosure, "transmission or provision" may include not only direct transmission or provision but also indirect transmission or provision through another device or by using an alternative route.

[0022] Expressions described in the singular in this disclosure may be interpreted as singular or plural unless explicit expressions such as "one" or "single" are used.

[0023] In this disclosure, terms including ordinal numbers, such as first, second, etc., may be used to describe various components, but said components are not limited by said terms. Such terms are used solely for the purpose of distinguishing one component from another. For example, without departing from the scope of this disclosure, the first component may be named the second component, and similarly, the second component may be named the first component.

[0024] In the flowchart described with reference to the drawings in this disclosure, the order of operations may be changed, several operations may be merged or some operations may be divided, and certain operations may not be performed.

[0025] FIG. 1 is a configuration diagram of a hybrid vehicle including a dual battery according to one embodiment.

[0026] As illustrated in FIG. 1, the hybrid vehicle includes a first battery (100) and a second battery (200) having a dual battery structure. The hybrid vehicle includes an engine (300), a motor (400), a transmission (410), an inverter (420), and a high-voltage battery (430), and may also include various other vehicle modules. A processor (500) can control various connected vehicle modules according to the battery status and vehicle status. The processor (500) may be included in an engine control unit (ECU).

[0027] A 12V second battery (200) is connected to a starter (310) that attempts to start the engine (300), and a 12V first battery (100) can be connected to an electronic generator (ALTERNATOR, ALT) (320) of the engine (300). The electronic generator (320) is connected to the engine pulley and can generate power through rotational force to supply power to the vehicle and the battery.

[0028] A high-current relay (hereinafter referred to as a relay) (230) connecting the first battery (100) and the second battery (200) is located between them, and the first battery (100) and the second battery (200) can be connected or disconnected by closing or opening the relay (230). It is explained that the relay (230) is controlled by a processor (500).

[0029] The first battery (100) is configured to respond to a load and is connected to a first battery sensor (110). The first battery sensor (110) can measure the state of the first battery (100), such as voltage, current, battery liquid temperature, and state of charge (SOC), and transmit the measurement information to a processor (500). The first battery (100) can be charged by an electronic generator (320).

[0030] The second battery (200) is intended to supply power in response to engine starting, and a second battery sensor (210) is connected to it. The second battery sensor (210) can measure the state of the second battery (200), for example, voltage, current, battery liquid temperature, and charge state, and transmit the measurement information to the processor (500).

[0031] A junction block (330) can be located on the connection line between the electronic generator (320) and the dual batteries. Electricity and power can be distributed to the internal components of the hybrid vehicle through the junction block (330).

[0032] The processor (500) detects an attempt to start the engine (300), checks the charge status of the first battery (100) and the second battery (200), and then controls (opens, closes) the relay (230).

[0033] The processor (500) can open the relay (230) to prevent electrical load fluctuations and controller resets caused by voltage drop when the driving mode of the hybrid vehicle changes (EV mode release). By doing so, the processor (500) causes only the voltage drop of the second battery (200) to occur when the EV mode is released, while maintaining the voltage of the first battery (100) stably, thereby preventing lamp flickering and preventing controller resets. Here, the EV mode refers to a mode in which the vehicle is driven only by the motor (400).

[0034] The processor (500) can display a specific message on the display of a terminal mounted inside the vehicle and can transmit the message to an external user terminal through the communication module of the terminal mounted inside the vehicle. At this time, the specific message may include a battery check message.

[0035] FIG. 2 is a flowchart illustrating a relay control method according to a first battery state in a vehicle's engine off state according to one embodiment.

[0036] Referring to FIG. 2, the processor (500) confirms that the engine is off (key off state) (S110).

[0037] The processor (500) checks whether the state of charge (SOC) of the first battery (100) is greater than or equal to a first threshold (S120). The state of charge is a value that expresses the charge amount of the first battery as a percentage of the maximum capacity and is used in the same way as a fuel gauge in a hybrid vehicle. At this time, the state of charge can be measured by the change in battery capacity over time using a current integration method. For example, the state of charge can be calculated by measuring the specific gravity and pH of the battery electrolyte using a chemical method, or by calculating the state of charge using the battery voltage using a voltage method. Alternatively, the state of charge can be calculated by measuring the current of the battery using a current integration method and integrating it over time, or by calculating the state of charge based on the pressure inside the battery using a pressure method. The method of calculating such a state of charge is one example and is not necessarily limited thereto, and can be calculated differently depending on the situation or actual applied conditions. Here, the first threshold refers to the minimum state of charge and can be expressed as, for example, 10% of the total capacity.

[0038] The processor (500) opens the relay (230) when the charge state is higher than the first threshold (S130). The first threshold may be, for example, 10% of the total capacity. By opening the relay (230) in this way, the occurrence of quiescent current flowing when the engine is off can be minimized. Meanwhile, generally, the battery sensor reads the battery voltage when the vehicle engine is off to calculate the state of charge (SOC). However, if the two batteries are connected, the parallel voltage is measured instead of the individual battery voltages, so the accurate charge state of each battery cannot be learned through the voltage-state of charge (SOC) table. However, when the relay is open, the voltages of the first battery (100) and the second battery (200) are measured, so the processor (500) can learn the independent charge state based on each battery voltage.

[0039] If the charge state of the first battery (100) is less than the first threshold, the processor (500) controls the first battery (100) to be charged by closing the relay (230) to start the vehicle (S140). When the relay (230) is closed, the discharged first battery (100) is charged using the second battery (200). Since the discharged battery has a low voltage, it can be charged by the potential difference. This is because even if the second battery (200) is in a charge state capable of operating the vehicle starter (310) to start the vehicle, the vehicle cannot be started if the first battery (100) is discharged and power is not supplied to each controller. Therefore, the processor (500) closes the relay (230) to charge the first battery (100) and makes it possible to start the vehicle. Meanwhile, the processor (500) can send a message notifying the discharge of the first battery to a connected terminal. Here, the terminal refers to a terminal mounted on a vehicle and having a display screen, or a user terminal linked to a hybrid vehicle.

[0040] Afterward, the processor (500) checks whether the charge state of the first battery is greater than or equal to a second threshold (S150). Here, the second threshold has a value greater than the first threshold.

[0041] The processor (500) can open the relay (230) through step S120 when the charge state of the first battery (100) is charged above a second threshold, and can continue to charge the first battery (100) by maintaining the closed state of the relay (230) when the charge state of the first battery (100) does not reach the second threshold.

[0042] FIG. 3 is a flowchart illustrating a relay control method according to one embodiment of a vehicle start.

[0043] Referring to FIG. 3, when the processor (500) detects an attempt to start the vehicle (S201), it opens the relay (230) (S203).

[0044] The processor (500) checks whether the vehicle start attempt is successful (S205), and if the vehicle start attempt fails, closes the relay (230) (S207). The processor (500) can connect the first battery (100) and the second battery (200) in parallel to charge the second battery (200). At this time, the processor (500) can send a battery check message.

[0045] After the processor (500) detects a restart in the relay closed state (S209), it checks whether the vehicle restart is successful (S211).

[0046] If the vehicle restart fails, the processor (500) sends a battery check message to a display device or user terminal inside the vehicle (S213).

[0047] When the vehicle restart is successful, the processor (500) puts the second battery (200) into charging mode (S215). When the second battery (200) is in charging mode, the processor (500) can control the driving mode of the hybrid vehicle so that it does not enter EV mode. That is, if the driving mode enters EV mode, the power generation of the electronic generator (320) stops, and the battery is not charged. Since it is important to charge the second battery (200) to enable starting, the processor (500) restricts the change to a driving mode (entering EV mode, disabling engine mode) that stops the power generation of the electronic generator (320). Through this, the second battery (200) can be charged through the electronic generator (320). The charging mode of the second battery is described in detail below with reference to FIG. 5.

[0048] Meanwhile, if the vehicle start attempt is successful in step S205, the processor (500) closes the relay (230) (S217). When the processor (500) confirms a normal vehicle start, it closes the relay (230) to immediately charge the battery, and can open the relay (230) when charging is complete. This prevents the sulfation phenomenon that may occur when the second battery (200) is over-discharged or left idle.

[0049] Subsequently, the processor (500) compares the charge amount of the second battery (200) at the current time with the discharge amount at the time of starting, and if the second battery is charged to a level greater than the discharge amount caused by starting, it opens the relay (230) (S219). Subsequently, the processor (500) maintains the relay in an open state while the hybrid vehicle is driving. In this way, when driving begins, the processor (500) charges the second battery (200) by the amount it was discharged due to starting, and then opens the relay (230). This prevents the second battery (200) from being discharged and ensures durability. Since sulfation occurs and battery durability deteriorates if the battery is left in a discharged state for a long time, if 1Ah is discharged from the second battery (200) at the time of starting, the processor (500) closes the relay (230) to charge it up to 1Ah, and then opens the relay (230).

[0050] FIG. 4 is a flowchart illustrating a control method for a charging mode of a second battery according to one embodiment.

[0051] Referring to FIG. 4, the processor (500) determines the charging conditions for entering the second battery (200) into a charging mode (S301). The charging conditions may vary. For example, as in step S215 of FIG. 3, if the vehicle restart is successful, the processor (500) may enter the second battery (200) into a charging mode. The processor (500) may enter the charging mode if the state of the second battery received from the second battery sensor (210) is below a reference value. The state parameters used to determine entry into the charging mode may be, for example, the state of charge (SOC), the starting voltage, etc. In addition, the processor (500) may set a charging cycle, and when the charging cycle arrives, determine that the charging conditions for entering the second battery (200) into a charging mode are satisfied.

[0052] When the charging conditions for entering the second battery (200) into a charging mode are met, the processor (500) closes the relay (230) (S303).

[0053] The processor (500) sets a target charging voltage based on the second battery status information and then starts charging the second battery (200) (S305). The processor (500) can set an optimal target voltage for the second battery (200) based on status information, such as the state of charge (SOC) and battery liquid temperature, received from the second battery sensor (210). For example, when the SOC is 70% and the battery liquid temperature is 25 degrees, 14.5V can be set as the target charging voltage.

[0054] Meanwhile, the processor (500) accumulates the charging time of the second battery and determines whether the full charge standard time has been reached (S307).

[0055] The processor (500) terminates the charging mode of the second battery (200) when the accumulated charging time exceeds the full charge reference time (S309). That is, the processor (500) terminates charging when the second battery (200) exceeds the full charge reference time. This is because, even if 95% is set as the target voltage, there is a problem where the charging mode is maintained because the aged battery does not reach the target voltage over time. Therefore, the processor (500) can set a full charge reference time that allows all batteries to be sufficiently charged, taking into account battery aging, and control the battery to be charged until the full charge reference time. In the case of some batteries, charging may be completed earlier than the full charge reference time, and even in this case, it may be recommended to continue charging for a certain period of time for battery durability.

[0056] At this time, if the processor (500) does not satisfy the charging target voltage after the charging is finished, it can generate a second battery check message and transmit it to a display inside the vehicle or to a user terminal.

[0057] The method for controlling the dual battery of a hybrid vehicle according to the vehicle condition and battery condition described so far is as shown in Table 1.

[0058] Vehicle and battery status Control method Purpose and Effects Engine stalled, first battery normal Relay open Since the load generating the independent SOC learning dark current for the first and second batteries is connected to the first battery, starting performance of the second battery can be secured when the relay is opened. Engine stalling, first battery discharge Relay close Even if the second battery is charged enough to operate the vehicle starter and start the engine, the vehicle cannot start if the first battery is discharged and power is not supplied to each controller; therefore, the relay is closed to charge the discharged first battery through the second battery. Attempted to start with the second battery but failed. Relay close. Enter 2nd Battery Charge Mode. Prohibit entry into EV Mode. By closing the relay and attempting to start using the parallel-connected batteries, starting performance is ensured, and starting is possible even when the second battery's durability expires. Successfully started with the second battery Open Relay after closing Relay Charging discharge amount by starting EV mode disabled Relay open It stably maintains the voltage of the first battery to prevent lamp flickering and other issues caused by electrical load fluctuations due to voltage drop, and prevents controller reset. 2nd battery charging mode Relay open When the second battery meets the charging conditions, it enters charging mode to ensure starting performance.

[0059] In this way, according to the present disclosure, by controlling the relay of the dual battery, it is possible to prevent electrical load fluctuations caused by voltage drop that may occur when changing the driving mode of the vehicle while ensuring the starting performance of the vehicle.

[0060] The embodiments of the present disclosure described above are not implemented only through devices and methods, but may also be implemented through a program that realizes a function corresponding to the configuration of the embodiments of the present disclosure or a recording medium on which such program is recorded.

[0061] Although embodiments of the present disclosure have been described in detail above, the scope of the present disclosure is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concepts of the present disclosure as defined in the following claims also fall within the scope of the present disclosure.

Claims

Claim 1 A method of operation for a processor controlling a dual battery installed in a hybrid vehicle, comprising: a step of, when a start attempt of the hybrid vehicle is detected, opening a relay located between a first battery for load and a second battery for start, and checking whether a first start using the second battery is successful; a step of, if the first start is successful, closing the relay to charge the second battery, and if the second battery is charged to a discharge amount greater than that of the first start, opening the relay; a step of, if the first start fails, closing the relay so that the first battery and the second battery are connected in parallel, and checking whether a second start using the first battery and the second battery is successful; and a step of, if the second start is successful, entering the second battery into a charging mode to charge the second battery. Claim 2 delete Claim 3 A method of operation according to claim 1, further comprising the step of transmitting a battery check message to a linked display or terminal if the second start fails. Claim 4 A method of operation according to claim 1, wherein the first battery is connected to an electronic generator and the second battery is connected to a starter that attempts to start, and the first battery and the second battery are connected or disconnected through the relay. Claim 5 In paragraph 4, the step of charging the second battery is a method of operation that restricts the change to a driving mode that stops the generation of the electronic generator when the second battery is in a charging mode. Claim 6 In paragraph 4, the step of charging the second battery is a method of operation in which the charging of the second battery is terminated and the relay is opened when the accumulated charging time reaches the full charge reference time. Claim 7 In claim 6, the step of charging the second battery is a method of operation in which a charging target voltage is set based on the status information of the second battery, and if the charging target voltage is not satisfied at the full charge reference time, a battery check message is transmitted to a linked display or terminal. Claim 8 A method of operation according to claim 1, further comprising the step of opening the relay when the charge state of the first battery is higher than a first threshold when the engine of the hybrid vehicle is turned off, and closing the relay to charge the first battery when the charge state of the first battery is lower than the first threshold. Claim 9 A method of operation according to claim 1, further comprising the step of opening the relay to stably maintain the voltage of the first battery when EV mode release is detected due to a change in the driving mode of the hybrid vehicle.

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