It may be possible for the second high voltage battery SB to communicate with a first controller Ctrl 1 of the first mobility apparatus MLT 1 or a battery management system (BMS) of the first high voltage battery MB, which will be described below, by wire or wirelessly, so that various sensing information (e.g., voltage, current, temperature, etc.) related to the state of charge (SoC) and the physical/electrical/chemical state of the second high voltage battery SB may be transmitted to the first controller Ctrl 1. However, not necessarily limited thereto, the above-mentioned information related to the second high voltage battery SB may also be transmitted to the first controller Ctrl 1 through a second controller Ctrl 2 of the second mobility apparatus MLT 2, which will be described below.

According to this embodiment of the present disclosure, the high voltage battery applied to the first high voltage battery MB and the second high voltage battery SB may include, for example, a plurality of battery cells (not shown) outputting a voltage of 2.7 to 4.2 V, and a set number of battery cells may be connected in series/parallel to each other to form one module. The high voltage battery may be in the form of one or more battery modules connected to each other in series/parallel and thus packaged in one battery package to output a desired voltage, e.g., a voltage of about 400 V, about 800 V, or several kV.

The first high voltage battery MB and the second high voltage battery SB may each include the BMS.

The BMS may include a battery management unit (BMU), a cell monitoring unit (CMU), and a battery junction box (BJB).

The BMS may perform a cell balancing function to ensure the performance of the entire battery pack by maintaining the voltage of each cell constant, a SoC function to calculate the capacity of the entire battery system, control of battery cooling, charging, and discharge, etc.

The BMU may receive information on each cell from the CMU and fulfill the functions of the BMS based thereon.

For example, the BMU may include two micro control units (MCUs), and each MCU may have one CAN communication port. A CAN interface may be included for the communication with a vehicle controller, which can be said to be the upper device of the BMS, and a CAN interface may be included to collect information from the CMU, which is the lower device thereof.

The CMU may be directly attached to a battery cell and monitor voltage, current, temperature, etc. The CMU may not perform calculations related to the BMS algorithm and may only serve to monitor. One CMU may be connected to multiple battery cells, and may transmit information on each cell to the BMU through a CAN interface.

The BJB may be the mechanism for determining the pack-level of the BMS and the medium that connects the high voltage battery and drivetrain. The BJB may measure and record a battery's voltage and the current flowing in and out of the battery to accurately calculate the SoC. In addition, the BJB may perform important functions for safety, such as monitoring of insulation as well as detecting of overcurrent.

The second high voltage battery SB may be a high-voltage battery with a lower voltage than the first high voltage battery MB, and, in this case, the second DC/DC converter L/H-DC may be a step-up DC/DC converter. In contrast, the second high voltage battery SB may be a high-voltage battery with a higher voltage than the first high voltage battery MB, and, in this case, the second DC/DC converter L/H-DC may be a step-down DC/DC converter. In addition, according to this embodiment, the second DC/DC converter L/H-DC may be a bidirectional converter, so it may be possible for the first high voltage battery MB and the second high voltage battery SB to charge and discharge each other.

According to this embodiment of the present disclosure, the second DC/DC converter L/H-DC may be built into the first mobility apparatus MLT 1 in the power system, but is not limited thereto. For example, unlike this embodiment, the second DC/DC converter L/H-DC may be provided as a separate component and may be additionally and detachably connected to the power system. In addition, the second DC/DC converter L/H-DC may be built into or detachably included in the second mobility apparatus MLT 2.

According to this embodiment of the present disclosure, for the detachable and electrical connection to the power system of the second high voltage battery SB, the power system of the first mobility apparatus MLT 1 may include first and second connectors C1 and C2, and the second high voltage battery SB may include third and fourth connectors C3 and C4.

For example, the first and second connectors C1 and C2 may be in the form of one integrated connector, and the third and fourth connectors C3 and C4 may also be in the form of one integrated connector.

The first connector C1 may be connected to the second DC/DC converter L/H-DC, and the second connector C2 may be connected to the inverter IN.

Meanwhile, although not shown, it is needless to say that a connector for transmitting signals may be added to transmit various sensing and state information on the second high voltage battery SB to the controller.

In addition, according to this embodiment of the present disclosure, the first controller Ctrl 1 may be the highest-level vehicle controller that controls all electric devices of the first mobility apparatus MLT 1, but is not necessarily limited thereto. That is, for example, the first controller Ctrl 1 in FIG. 1 may be a power controller subordinate to a vehicle controller.

Furthermore, as described above, the first controller Ctrl 1 according to this embodiment may include computer-readable recording media that store operating systems, logic instructions, input/output information, etc. and one or more processors that read them and perform the operation of making determinations and decisions, doing calculations, etc. to control the functions.

The second high voltage battery SB in FIG. 1 may be installed in the second mobility apparatus MLT 2 as shown in FIG. 2.

The second mobility apparatus MLT 2 may include a frame FRM, a second left wheel LW installed on the left side of the frame FRM, a second right wheel RW installed on the right side of the frame FRM, a second left driving motor LM for providing a driving force to the second left wheel LW, a second right driving motor RM for providing a driving force to the second right wheel RW, and the second controller Ctrl 2.

The second high voltage battery SB may be fixed to and installed in the second mobility apparatus MLT 2, but is not necessarily limited thereto. That is, the second high voltage battery SB may be removably installed in the second mobility apparatus MLT 2. As a result, it may be possible to replace the second high voltage battery SB mounted on the frame FRM with the SoC of being fully discharged with a new second high voltage battery SB with the SoC of being fully charged.

When the second high voltage battery SB is fixed to and installed in the second mobility apparatus MLT 2, the second mobility apparatus MLT 2 may include a charging connector for charging the second high voltage battery SB.

The frame FRM may form the exterior of the second mobility apparatus MLT 2 and may serve to accommodate other components.

The frame FRM may include a second pivot mechanism PM2 as a second connection mechanism, and the second pivot mechanism PM2 may be detachably and pivotably connected to a first pivot mechanism PM1, which is a first connection mechanism fixed to the body of the first mobility apparatus MLT 1.

For example, the first pivot mechanism PM1 may include an extension rod ER extending rearwardly from the body of the first mobility apparatus MLT 1 and a pivot pin PN protruding upward from an end of the extension rod ER.

In addition, the second pivot mechanism PM2 may include a triangular-shaped extension portion EP protruding forward from the frame FRM of the second mobility apparatus MLT 2 and a pivot ring PR into which the pivot pin PN may be rotatably inserted at the end of the extension portion EP.

When the pivot pin PN is inserted into the pivot ring PR, the linear movement of the pivot pin PN may be limited, and it may only rotate in the Z-axis direction in FIG. 2. Therefore, when the second mobility apparatus MLT 2 is pivotably connected, the linear movement of the second mobility apparatus MLT 2 may be limited about the pivot connection point with respect to the first mobility apparatus MLT 1, and the second mobility apparatus MLT 2 may only rotate about the Z axis.

When driving in the forward direction, that is, in the X-axis direction, the first mobility apparatus MLT 1 and the second mobility apparatus MLT 2 may remain in a straight line even without separate control of the steering of the second mobility apparatus MLT 2.

According to this embodiment, the pivot mechanisms as the first and second connection mechanisms may be included, but it is not necessarily limited thereto. For example, the first and second connection mechanisms may be well-known mechanisms that enable non-rotational connection about the Z axis.

The rotation axis of the second left driving motor LM may be connected to the second left wheel LW so that the second left driving motor LM may supply a driving force to the second left wheel LW.

In addition, the rotation axis of the second right driving motor RM may be connected to the second right wheel RW so that the second right driving motor RM may supply a driving force to the second right wheel RW.

Because the second left wheel LW and the second right wheel RW may respectively be connected to the second left driving motor LM and the second right driving motor RM, it may be possible to drive them independently of each other.

It may be possible to drive the second left driving motor LM and the second right driving motor RM in the forward and reverse directions. When they are driven in the forward direction, the second mobility apparatus MLT 2 may travel forward, and, when they are driven in the reverse direction, it may travel backwards.

For example, the second left driving motor LM and the second right driving motor RM may each be designed as an in-wheel driving system where a driving motor is installed within a wheel, but they are not necessarily limited thereto.

In addition, unlike this embodiment, the second mobility apparatus MLT 2 may be driven in the matter that the left and right sides of the second mobility apparatus MLT 2 are not independent of each other and the power of one common motor is divided and transmitted to the second left wheel LW and the second right wheel RW. To this end, a differential gear may be disposed between a common second driving motor and the second left wheel LW and the second right wheel RW. That is, the power of the common second driving motor may be distributed to the second left wheel LW and the second right wheel RW by the differential gear. In this case, a torque vectoring means may be added to distribute torque among the second left wheel LW and the second right wheel RW.

Referring to FIG. 2, the second controller Ctrl 2 may control the second left driving motor LM and the second right driving motor RM to allow the second mobility apparatus MLT 2 to travel forward and backward. In addition, when the steering of the second mobility apparatus MLT 2 is required, the second controller Ctrl 2 may control the torque or the number of rotations of each of the second left driving motor LM and the second right driving motor RM to change the direction in which the second mobility apparatus MLT 2 travels. That is, the driving of the second left driving motor LM and the second right driving motor RM may be separately controlled, so that it may be possible to achieve the steering of the second mobility apparatus MLT 2 without a separate steering device.

In addition, as described above, a wired or wireless communication means for transmitting information between the first and second mobilities MLT 1 and MLT 2 may be included.

Meanwhile, according to this embodiment, the first controller Ctrl 1 or the second controller Ctrl 2 may include a memory and a processor. Computer instructions for performing the functions of a corresponding controller may be stored in the memory, and the processor may perform the above-mentioned functions by loading the instructions from the memory and executing them.

For example, the memory may include at least one of a hard disk drive (HDD), a solid-state drive (SSD), a silicon disk drive (SDD), a ROM, a RAM, a CD-ROM, a magnetic tape, a floppy disk, and an optical data storage device.

In addition, for example, the processor may include at least one of a computer, a microprocessor, a central processing unit (CPU), an ASIC, an electric circuit, and a logic circuit.

The first and second connectors C1 and C2 of the first mobility apparatus MLT 1 and the third and fourth connectors C3 and C4 of the second mobility apparatus MLT 2 may be connected to each other, and the connector for transmitting signals may be connected, so that it may be possible that the first mobility apparatus MLT 1 and the second mobility apparatus MLT 2, that is, the first controller Ctrl 1 and the second controller Ctrl 2, communicate with each other.

When the first mobility apparatus MLT 1 starts to drive forward with the first mobility apparatus MLT 1 and the second mobility apparatus MLT 2 mechanically and electrically connected to each other, according to the signal of the driving speed transmitted from the first connector C1, the second controller Ctrl 2 may control the second left driving motor LM and the second right driving motor RM to enable the second mobility apparatus MLT 2 to drive straight ahead.

In that case, some or all of the speed, the position of the gear, the steering angle, the information on an accelerator pedal sensor (APS), and the information on a brake pedal sensor (BPS) of the first mobility apparatus MLT 1 may be transmitted to the second mobility apparatus MLT 2.

For example, the second controller Ctrl 2 of the second mobility apparatus MLT 2 may determine whether the first mobility apparatus MLT 1 is traveling forward or backward, based on some or all of the speed, the position of the gear, the information on an accelerator pedal sensor (APS), and the information on a brake pedal sensor (BPS) of the first mobility apparatus MLT 1. However, the present disclosure is not limited thereto, and it goes without saying that the second controller Ctrl 2 of the second mobility apparatus MLT 2 may receive the information on whether the first mobility apparatus MLT 1 is traveling forward or backward directly from the first controller Ctrl 1.

When the first mobility apparatus MLT 1 is traveling forward, the second controller Ctrl 2 may drive the second left driving motor LM and the second right driving motor RM in the forward direction to allow the second mobility apparatus MLT 2 to drive straight ahead. Furthermore, when the first mobility apparatus MLT 1 is traveling backward, the second controller Ctrl 2 may drive the second left driving motor LM and the second right driving motor RM in the reverse direction to allow the second mobility apparatus MLT 2 to drive backward.

In addition, the second controller Ctrl 2 may determine how the first mobility apparatus MLT 1 is being steered based on information on the steering angle of the first mobility apparatus MLT 1, and may steer the second mobility apparatus MLT 2 accordingly.

The second mobility apparatus MLT 2 may not include a separate steering device such as a steering wheel and a steering rack, and it may be possible to steer the second mobility apparatus MLT 2 by controlling the torque of the second left driving motor LM and the second right driving motor RM.

That is, the second controller Ctrl 2 may calculate a driving torque for driving and a steering torque for steering for each of the second left driving motor LM and the second right driving motor RM to perform the control operation.

For example, for the steering of the second mobility apparatus MLT 2, the steering torque values of the second left driving motor LM and the second right driving motor RM according to the steering angle of the first mobility apparatus MLT 1 may be included in a lookup table or a calculation program.

When the second mobility apparatus MLT 2 drives straight ahead, the speed of the second mobility apparatus MLT 2 may be controlled to be no greater than that of the first mobility apparatus MLT 1. As a result, the pivot connection between the first mobility apparatus MLT 1 and the second mobility apparatus MLT 2 may be maintained at a pivot angle within a predetermined range. For example, when the speed of the second mobility apparatus MLT 2 driving straight ahead is controlled to be no greater than that of the first mobility apparatus MLT 1, at the pivot connection point, the pivot angle between the second mobility apparatus MLT 2 and the first mobility apparatus MLT 1 may be maintained at 0 degree, i.e., the angle where the first mobility apparatus MLT 1 and the second mobility apparatus MLT 2 are in a straight line.

When the second mobility apparatus MLT 2 is driving forward, it may be controlled to follow the first mobility apparatus MLT 1, so that the driving of multiple mobilities connected to each other may be smoothly performed.

FIG. 3 shows the process of controlling the SOC of batteries of a dual battery system according to an embodiment of the present disclosure, which will be described below.

The process in FIG. 3 may be performed by the first controller Ctrl 1 or the second controller Ctrl 2, but, in this embodiment, for convenience of description, the process performed by the first controller Ctrl 1 will be described.

First, at S10, the driving control mode of the first mobility apparatus MLT 1, that is, the power mode according to the driving state thereof, may be the “IG2 on” mode or the “EV Ready” mode.

Examples of the driving control mode may include the IG1, IG2, and EV Ready modes.

In the state of IG1 on, the corresponding switches of the related relays may have been turned on so that power can be supplied to designated electronic devices not related to driving, including convenience devices in a vehicle, such as an air conditioning system and an AVN.

In the state of IG2 on, the corresponding switches of the related relays may have been turned on so that power can be supplied to all electronic devices in a vehicle, including various controllers.

In addition to the state of IG2 on, the state of EV Ready may be a state in which a vehicle control unit has turned capable of starting driving at any time according to signals sensed by an accelerator pedal sensor (APS) and/or a brake pedal sensor (BPS). When the EV Ready mode has started, control functions necessary for driving may be activated.

The first controller Ctrl 1 may check whether a long-term parking battery protection mode has been selected at S20.

An in-vehicle user interface such as an AVN screen may have a button that allows a driver to select a long-term parking battery protection mode.

For example, when a destination such as an airport at a set location is determined in conjunction with a navigation system, a pop-up window for selecting a long-term parking battery protection mode may be displayed on the AVN screen accordingly.

According to this embodiment, after a long-term parking battery protection mode has been selected, SOC control may be performed according to the selected mode, but the present disclosure is not limited thereto. The SOC control for protecting batteries during long-term parking, which will be described below, may be carried out automatically as set even when no selection is made by a driver.

At S30 following S20, the first controller Ctrl 1 may determine a first target SOC for the first high voltage battery MB and a second target SOC for the second high voltage battery SB.

The first target SOC and the second target SOC may be SOCs to minimize natural discharge and/or degradation of a corresponding battery.

Generally, natural discharge decreases as the SOC increases, so the SOC should be increased to minimize natural discharge. However, because degradation worsens when the SOC is excessively large or small, it may be desirable to determine an appropriate SOC to minimize both natural discharge and degradation. In addition, because natural discharge increases as the ambient temperature rises, it may be desirable to consider the ambient temperature as well.

For example, aiming to minimize both natural discharge and degradation, the first target SOC may be the average value of a SOC for minimizing natural discharge of the first high voltage battery MB and a SOC for minimizing degradation thereof. Likewise, the second target SOC may be the average value of a SOC for minimizing natural discharge of the second high voltage battery SB and a SOC for minimizing degradation thereof.

In addition, for example, the SOC range of each battery to minimize natural discharge and/or degradation may be determined in advance and stored in a memory. That is, a first lower limit SOC and a first upper limit SOC for the first high voltage battery MB may be predetermined and stored in a memory, and a second lower limit SOC and a second upper limit SOC for the second high voltage battery SB may be predetermined and stored in a memory. Furthermore, a SOC range for minimizing natural discharge and a SOC range for minimizing degradation may be prepared separately, or an integrated SOC range to integrate the two ranges may be prepared.