Patent Description:
For example, <CIT> discloses that a remaining capacity or a state of charge of a battery (electric power storage unit) mounted in a battery vehicle (electric vehicle) is detected in real time, and the detection result is displayed on a remaining capacity indicator.

<CIT> shows an electric power device and method according to the preamble of claims <NUM> and <NUM>.

When the plurality of electric power storage units have different specifications such as a temperature, a degree of deterioration, or a type, even if the average value of the charging rates (SOCs) of the respective electric power storage units is simply calculated, the calculated average value may not be the overall SOC of the plurality of electric power storage units.

The present invention has been devised taking into consideration the aforementioned problems, and has the object of providing an electric power device, a state of charge.

According to a first aspect of the present invention, according to claim <NUM>, there is provided an electric power device including a plurality of electric power storage units that are chargeable and dischargeable. The electric power device includes a state of charge calculation unit configured to calculate an overall state of charge of the plurality of electric power storage units, based on a sum of full charge capacities of the respective electric power storage units and a sum of current charge capacities of the respective electric power storage units.

According to a second aspect of the present invention, according to claim <NUM>, there is provided a display device including a receiving unit configured to receive the overall state of charge of the plurality of electric power storage units from the above- mentioned electric power device. The display device is <NUM> configured to display the received overall state of charge of the plurality of electric power storage.

According to a third aspect of the present invention, according to claim <NUM>, there is provided a state of charge calculation method for an electric power device including a plurality of electric power storage units that are chargeable and dischargeable. The method includes the steps of acquiring full charge capacities of the plurality of electric power storage units, respectively, calculating a sum of the plurality of full charge capacities, acquiring current charge capacities of the plurality of electric power storage units, respectively, calculating a sum of the plurality of current charge capacities, and calculating an overall state of charge of the plurality of electric power storage units based on the sum of the full charge capacities and the sum of the current charge capacities.

According to a fourth aspect of the present invention, according to claim <NUM>, there is provided a program causing a computer to execute the steps of acquiring full charge capacities of a plurality of electric power storage units, respectively, calculating a sum of the plurality of full charge capacities, acquiring current charge capacities of the plurality of electric power storage units, respectively, calculating a sum of the plurality of current charge capacities, and calculating an overall state of charge of the plurality of electric power storage units based on the sum of the full charge capacities and the sum of the current charge capacities.

According to a fifth aspect of the present invention, according to claim <NUM>, there is provided a storage medium storing the above-mentioned program.

According to the present invention, by using the sum of the full charge capacities of the respective electric power storage units and the sum of the current charge capacities of the respective electric power storage units, it is possible to accurately calculate the overall state of charge of the plurality of electric power storage units. Further, in the present invention, it is possible to display the overall state of charge of the plurality of electric power storage units acquired in this way.

Hereinafter, preferred embodiments of an electric power device, a display device, a state of charge calculation method, a program, and a storage medium according to the present invention will be exemplified and described below with reference to the accompanying drawings.

<FIG> is a configuration diagram of an embodiment of an electric power device <NUM> according to a present embodiment. <FIG> illustrates a case where the electric power device <NUM> according to the present embodiment is applied to an electric power supply system <NUM> (electric power supply system). The electric power supply system <NUM> supplies electric power to a drive motor <NUM>. The drive motor <NUM> is a drive source (load) of a vehicle <NUM>.

As shown in <FIG> and <FIG>, the vehicle <NUM> is a four-wheeled electric vehicle. Four detachable batteries 16a to 16d (electric power storage units) are detachably mounted in the vehicle <NUM>. The four detachable batteries 16a to 16d constitute the electric power device <NUM>. The four detachable batteries 16a to 16d supply electric power to the drive motor <NUM> in <FIG>. In the following description, when the plurality of detachable batteries 16a to 16d are not particularly distinguished, they are also referred to as detachable batteries <NUM> when not particularly distinguished from each other. Further, each of the detachable batteries <NUM> is charged by an external charger (not illustrated) in a state of being detached from the vehicle <NUM>. That is, the detachable batteries <NUM> are chargeable and dischargeable electric power storage devices.

In the present embodiment, the vehicle <NUM> may be any vehicle in which the drive motor <NUM> is mounted, e.g., an electrically driven vehicle such as an electric vehicle, or a hybrid vehicle. Therefore, the application of the electric power device <NUM> according to the present embodiment is not limited to a four-wheeled electric vehicle. The electric power device <NUM> can be applied to electric power supply systems of various vehicles such as one-wheeled, two-wheeled, and four-wheeled vehicles.

The application of the electric power device <NUM> is not limited to the electric power supply system <NUM> of the vehicle <NUM>. The electric power device <NUM> can be applied to various electric power supply systems that supply power from the detachable batteries <NUM> to loads such as the drive motor <NUM>. Therefore, the electric power device <NUM> can be applied to an electric power supply system that is capable of supplying electric power to a load in various mobile bodies including the vehicle <NUM> and an aerial vehicle, and various electronic devices.

Further, the detachable battery <NUM> may be a portable electric power storage device that can be attached to and detached from the electric power device <NUM>, the vehicle <NUM>, or the like. Accordingly, the electric power device <NUM> can employ various types of electric power storage devices as the detachable battery <NUM>, including standard battery packs, high-power battery packs, high-capacity battery packs, and batteries for hybrid vehicles. The number of the detachable batteries <NUM> included in the electric power device <NUM> may be two or more.

In the following description, as shown in <FIG>, a case in which electric power is supplied from four detachable batteries <NUM> to the drive motor <NUM> in the electric power supply system <NUM> of a four-wheeled electric vehicle will be described.

As shown in <FIG> and <FIG>, in the vehicle <NUM>, a seat <NUM> is provided at a substantially central portion in a front-rear direction (a direction of arrow A as a vehicle longitudinal direction) of a vehicle body <NUM>. That is, the seat <NUM> is provided at a substantially intermediate position between front wheels 20F and rear wheels 20R. The front wheels 20F are provided at locations (front portion) in the direction of arrow Af in the vehicle <NUM>. The rear wheels 20R are provided at locations (rear portion) in the direction of arrow Ab in the vehicle <NUM>. The seat <NUM> is a driver's seat. The four detachable batteries 16a to 16d (<NUM>) are disposed in the left-right direction of the vehicle body <NUM> (a direction of arrow B as the vehicle widthwise direction).

More specifically, two electric power storage device housing units <NUM> are provided in the vicinity of the upper side of one of the left rear wheels 20R in a direction of arrow B1 (left portion) in the vehicle body <NUM>. Each of the two electric power storage device housing units <NUM> can accommodate one detachable battery <NUM>. The two electric power storage device housing units <NUM> are arranged in the direction of arrow B. Further, two electric power storage device housing units <NUM> are provided in the vicinity of the upper side of one of the left rear wheels 20R in a direction of arrow B2 (right portion) in the vehicle body <NUM>. Each of the two electric power storage device housing units <NUM> can accommodate one detachable battery <NUM>. The two electric power storage device housing units <NUM> are arranged in the direction of arrow B. A lid member <NUM> is provided in a direction of arrow Ab (rear portion) of each electric power storage device housing unit <NUM>. The lid member <NUM> is opened when the detachable battery <NUM> is attached or detached. Incidentally, the arrangement of the four detachable batteries 16a to 16d are not limited to the arrangement of <FIG> and <FIG>. The four detachable batteries 16a to 16d can be disposed at arbitrary positions in the vehicle <NUM> within an area where the detachable batteries <NUM> do not hinder the driving operation of a driver seated on the seat <NUM>.

Returning to <FIG>, the electric power device <NUM> (electric power supply system <NUM>) includes a vehicle integrated control unit <NUM> (state of charge calculation unit), DC/DC converters 32a to 32d, a joint box <NUM>, and an inverter <NUM>. The electric power supply system <NUM> is also provided with a display device <NUM>. Further, the respective detachable batteries 16a to 16d include battery management units 40a to 40d (hereinafter referred to as BMUs 40a to 40d). In the following description, the vehicle integrated control unit <NUM> may also be referred to as a control unit <NUM>. When the DC/DC converters 32a to 32d are not particularly distinguished from each other, they may also be referred to as DC/DC converters <NUM>. Further, when the plurality of BMUs 40a to 40d are not particularly distinguished from each other, they may also be referred to as BMUs <NUM>.

The control unit <NUM> includes a communication unit (transmission unit) 30a. The display device <NUM> includes a communication unit (receiving unit) 38a. The communication units 30a and 38a are connected to CANs <NUM> and <NUM>, respectively. The CAN <NUM> communicates with each device in the vehicle <NUM>. The CAN <NUM> communicates with the respective devices that are related to the detachable batteries 16a to 16d. The DC/DC converters 32a to 32d and the BMU 40a to BMU 40d of the respective detachable batteries 16a to 16d are connected to the CAN <NUM>.

The control unit <NUM> is a computer (information processing device). The control unit <NUM> is an ECU (electronic control unit) mounted in the vehicle <NUM>. The control unit <NUM> realizes various functions including calculation of a state of charge described later by reading and executing programs stored in a storage unit 30b. The storage unit 30b is a non-transitory storage medium. That is, the control unit <NUM> acquires an ignition signal from an ignition switch <NUM>. The ignition switch <NUM> is a drive switch of the vehicle <NUM>. The ignition signal is an ON signal. Further, the control unit <NUM> acquires accelerator pedal opening information from an accelerator pedal sensor <NUM>. In this case, the control unit <NUM> sets the torque of the drive motor <NUM> in accordance with the accelerator pedal opening information. The control unit <NUM> outputs the set torque from the communication unit 30a to the CAN <NUM> as a torque command value. Further, the control unit <NUM> sets a current command value according to the torque command value. The current command value is a PWM signal for converting the output voltage of the detachable battery <NUM>. The control unit <NUM> outputs the set current command value from the communication unit 30a to the CAN <NUM>.

Further, the control unit <NUM> acquires a lid opening/closing signal from a lid switch <NUM>. The lid opening/closing signal is a signal indicating a detection result of opening/closing of the lid member <NUM>. The control unit <NUM> sets the display content of the display device <NUM> according to the open state or the closed state of the lid member <NUM> indicated by the lid opening/closing signal. The control unit <NUM> outputs a display control signal indicating the set display content from the communication unit 30a to the CAN <NUM>.

Further, when the communication unit 30a acquires (receives) the information of the detachable batteries 16a to 16d from the BMU 40a to BMU 40d via the CAN <NUM>, the control unit <NUM> grasps an SOC (state of charge, hereinafter also referred to as a charging rate or charge capacity) of each of the plurality of detachable batteries 16a to 16d based on the acquired information. When any of the detachable batteries 16a to 16d has the SOC less than the predetermined value, the control unit <NUM> sets the display content indicating that the replacement of such detachable batteries 16a to 16d is notified. The control unit <NUM> outputs a display control signal indicating the set display content from the communication unit 30a to the CAN <NUM>.

Furthermore, the control unit <NUM> determines whether or not each of the detachable batteries 16a to 16d is loaded in the electric power storage device housing unit <NUM>, based on the information of each of the detachable batteries 16a to 16d acquired by the communication unit 30a. That is, the control unit <NUM> determines whether or not the detachable batteries 16a to 16d and the DC/DC converters 32a to 32d are electrically connected to each other, respectively. The control unit <NUM> sets the display content according to the determination result. The control unit <NUM> outputs a display control signal indicating the set display content from the communication unit 30a to the CAN <NUM>.

Further, the control unit <NUM> calculates the overall SOC of the plurality of detachable batteries 16a to 16d from the information of each of the detachable batteries 16a to 16d acquired by the communication unit 30a. The overall SOC herein means an SOC (charging rate) of electric power storage device when the plurality of detachable batteries 16a to 16d are regarded as one electric power storage device. The control unit <NUM> sets the display content of the calculated overall SOC of each of the detachable batteries 16a to 16d. The control unit <NUM> outputs a display control signal indicating the set display content from the communication unit 30a to the CAN <NUM>.

The BMUs 40a to 40d each manage the SOC, the temperature (temperature factor), the deterioration degree (deterioration level, deterioration factor), the internal resistance, and the current charge capacity as a remaining capacity, of each of the detachable batteries 16a to 16d, as well as connection states between the detachable batteries 16a to 16d and the DC/DC converters 32a to 32d, respectively. The BMUs 40a to 40d also manage the specifications (specification difference value such as a specification factor), the specification values or initial values of the full charge capacities, and the current full charge capacities, concerning the detachable batteries 16a to 16d. The BMUs 40a to 40d output these pieces of information to the CAN <NUM>.

Therefore, the control unit <NUM> acquires the current charge capacities, the current full charge capacities, and the specification values or initial values of the full charge capacities, and the like of the detachable batteries 16a to 16d, from the BMUs 40a to 40d. The specification value of the full charge capacity refers to a standard value of the full charge capacity of each of the detachable batteries 16a to 16d. The initial value of the full charge capacity refers to a value (initial full charge amount) of the full charge capacity at the start of use (at the time of shipment from the factory) of each of the detachable batteries 16a to 16d.

The DC/DC converters <NUM> each convert the output voltage of each of the detachable batteries <NUM> according to the current command value. The converted output voltage is output to the joint box <NUM>. The joint box <NUM> supplies DC power from each of the detachable batteries <NUM> to the inverter <NUM>. The inverter <NUM> converts the DC power supplied from the joint box <NUM> into three-phase AC power in accordance with the torque command value. The converted three-phase AC power is supplied to the drive motor <NUM>. Further, the inverter <NUM> outputs the rotational speed information and the actual torque information of the drive motor <NUM> to the CAN <NUM>.

The display device <NUM> is configured by a screen <NUM> (see <FIG>) and a processing device. The screen <NUM> is set on a dashboard or the like of the vehicle <NUM>. The processing device processes characters or images to be displayed on the screen <NUM>. Information from the inverter <NUM> or the drive motor <NUM> is input to (or received by) the display device <NUM> via the communication unit 38a. The SOC information (information on various charging rates or charge capacities) of the detachable batteries <NUM> and a display control signal of the control unit <NUM> are input to (or received by) the display device <NUM> from the CAN <NUM> via the communication unit 38a. The display device <NUM> displays a state of each of the detachable batteries <NUM> based on various kinds of information input to the communication unit 38a.

<FIG> is a diagram illustrating a display example of the display device <NUM>. The display device <NUM> includes battery remaining amount display units 52a to 52d, a total remaining amount display unit <NUM>, open/closed state display units 56a to 56d, battery replacement display unit 58a to 58d, and battery connection state display unit 60a to 60d.

Each of the battery remaining amount display units 52a to 52d are provided on the right side of the screen <NUM> of the display device <NUM>. Among them, the two battery remaining amount display units 52a and 52b on the right side correspond to the two detachable batteries 16a and 16b. The two detachable batteries 16a and 16b are disposed on the right side of the vehicle body <NUM> (see <FIG> and <FIG>). The two battery remaining amount display units 52c and 52d on the left side correspond to the two detachable batteries 16c and 16d. The two detachable batteries 16c and 16d are disposed on the left side of the vehicle body <NUM>.

The battery remaining amount display units 52a to 52d display the numbers of the detachable batteries 16a to 16d, respectively. Each of the battery remaining amount display units 52a to 52d displays an illustration simulating a dry battery in which a bar-shaped graph is arranged. Each of the battery remaining amount display units 52a to 52d displays a numerical value of the SOC of each of the detachable batteries 16a to 16d. The bar graph inside the dry battery illustration changes in the vertical direction in accordance with the magnitude of the SOC of each of the corresponding detachable batteries 16a to 16d.

In <FIG>, ten segments are arranged inside the dry battery illustration. The ten segments are rectangular. The ten segments are arranged in the vertical direction. Each segment is formed of, for example, an LED. When one segment is illuminated or turned on, <NUM> % of the SOC is displayed. In <FIG>, an illuminated state is illustrated by hatching. In <FIG>, a non-illuminated (extinguished or turned off) state is shown in white. Therefore, each of the battery remaining amount display units 52a to 52d is illuminated in order from the lowermost segment to the uppermost segment in accordance with the magnitude of the SOC of the corresponding detachable batteries 16a to 16d. Thus, the magnitude of the SOC is schematically displayed.

In <FIG>, none of segments are illuminated. <FIG> shows that the SOC of each of the detachable batteries 16a to 16d is <NUM> %. In <FIG>, all segments are illuminated for one detachable battery 16a. <FIG> shows that the SOC of the detachable battery 16a is <NUM> %. In <FIG>, the three lowest segments are illuminated. <FIG> shows that the SOC of the detachable battery 16a is <NUM> %. In <FIG>, the lowest segment is illuminated. <FIG> shows that the SOC of the detachable battery 16a is <NUM> %.

In this case, the color of the illuminated segment may be changed according to the magnitude of the SOC. In <FIG> and <FIG>, the direction of hatching in the segments is different from that in <FIG> and <FIG> show that the segments are illuminated in a color that is different from a color of the segments in <FIG>.

Around an illustration simulating a dry battery in each of the battery remaining amount display units 52a to 52d, the open/closed state display units 56a to 56d, the battery replacement display units 58a to 58d, and the battery connection state display units 60a to 60d are arranged, respectively. These display units are provided around the battery remaining amount display units 52a to 52d of the corresponding detachable batteries 16a to 16d, respectively.

If any of the open/closed state display units 56a to 56d is illuminated, it indicates that the lid member <NUM> of the electric power storage device housing unit <NUM> housing a corresponding one of the detachable batteries 16a to 16d is open. If any of the open/closed state display units 56a to 56d is not illuminated, it indicates that such a lid member <NUM> is closed. In <FIG>, the illuminated state is indicated by solid lines. In <FIG>, the non-illuminated state is indicated by broken lines.

If any of the battery replacement display units 58a to 58d is illuminated, it indicates that a corresponding one of the detachable batteries 16a to 16d needs to be replaced. If any of the battery replacement display units 58a to 58d is not illuminated, it indicates that replacement is unnecessary. In <FIG>, the illuminated state is indicated by solid lines. In <FIG>, the non-illuminated state is indicated by broken lines.

If any of the battery connection state display units 60a to 60d is illuminated, it indicates that a corresponding one of the detachable batteries 16a to 16d is loaded in the electric power storage device housing unit <NUM>. If any of the battery connection state display units 60a to 60d is illuminated, it indicates that the corresponding one of the detachable batteries 16a to 16d and a corresponding one of the DC/DC converters 32a to 32d are electrically connected to each other. In addition, if any of the battery connection state display units 60a to 60d is not illuminated, it indicates that a corresponding one of the detachable batteries 16a to 16d is not loaded in the electric power storage device housing unit <NUM>. Alternatively, if any of the battery connection state display units 60a to 60d is not illuminated, it indicates that the corresponding one of the detachable batteries 16a to 16d and the corresponding one of the DC/DC converters 32a to 32d are not electrically connected to each other even when the corresponding detachable battery is loaded. In <FIG>, the illuminated state is indicated by a black circle. In <FIG>, the non-illuminated state is indicated by a white circle.

The total remaining amount display unit <NUM> displays the overall SOC of the four detachable batteries 16a to 16d. The total remaining amount display unit <NUM> is configured by ten segments. The ten segments are arranged in a horizontal direction. Each segment is formed of, for example, an LED. When one segment is illuminated, <NUM> % of the SOC is displayed. Accordingly, the total remaining amount display unit <NUM> is illuminated in order from the leftmost segment (E indicating <NUM> % SOC) toward the rightmost segment (F indicating <NUM> % SOC) according to the magnitude of the overall SOC of each of the detachable batteries 16a to 16d. Thus, an approximate magnitude of the SOC is displayed.

<FIG> illustrate a change in display content of the display device <NUM> before and after the battery replacement for one detachable battery 16a. For each of the other detachable batteries 16b to 16d, the display content of the display device <NUM> change in the same manner at the time of battery replacement.

<FIG> shows a case where the detachable battery 16a is housed in the electric power storage device housing unit <NUM> (see <FIG> and <FIG>), the lid member <NUM> is closed, and the SOC of the detachable battery 16a is <NUM> %. In this case, all the segments in the battery remaining amount display unit 52a are illuminated. The characters "<NUM>" indicating that the numerical value of the SOC are displayed in the battery remaining amount display unit 52a. In addition, the battery connection state display unit 60a is illuminated. The open/closed state display unit 56a and the battery replacement display unit 58a are not illuminated.

<FIG> shows a case where the SOC of the detachable battery 16a has dropped to <NUM> %. In this case, the three lowermost segments are illuminated in the battery remaining amount display unit 52a. The characters "<NUM>%" indicating the numerical value of the SOC are displayed in the battery remaining amount display unit 52a. Since the SOC has dropped, the three lowermost segments are illuminated in a color that is different from a color in the case of <FIG>.

<FIG> shows a case where the SOC of the detachable battery 16a has dropped to <NUM> %. In this case, in the battery remaining amount display unit 52a, the one lowermost segment is illuminated. The characters "<NUM>%" indicating the numerical value of the SOC are displayed in the battery remaining amount display unit 52a. When the battery replacement display unit 58a is illuminated, the driver or the like is prompted to replace the detachable battery 16a.

Seeing the screen display of <FIG>, the driver or the like opens the lid member <NUM> (see <FIG> and <FIG>) of the electric power storage device housing unit <NUM> that houses the detachable battery 16a. As a result, the screen <NUM> of the display device <NUM> is switched to the display content of <FIG>. In <FIG>, the illuminated open/closed state display unit 56a notifies the driver or the like that the lid member <NUM> is open.

When the driver or the like removes the detachable battery 16a from the electric power storage device housing unit <NUM>, the screen <NUM> of the display device <NUM> is switched to the display content of <FIG>. In <FIG>, the battery connection state display unit 60a is not illuminated. In <FIG>, the open/closed state display unit 56a and the battery replacement display unit 58a are illuminated. Further, the battery remaining amount display unit 52a turns off all the segments. The battery remaining amount display unit 52a displays the characters "<NUM>%" indicating the numerical value of the SOC.

Next, when the driver or the like loads a detachable battery 16a in a full charge state into the electric power storage device housing unit <NUM>, the screen <NUM> of the display device <NUM> is switched to the display content of <FIG>. In <FIG>, the battery connection state display unit 60a, the open/closed state display unit 56a and the battery replacement display unit 58a are all illuminated. The battery remaining amount display unit 52a turns on all the segments. The battery remaining amount display unit 52a displays the characters "<NUM>" indicating the numerical value of the SOC.

Next, when the driver or the like closes the lid member <NUM>, the screen <NUM> of the display device <NUM> is switched to the display content of <FIG>. As a result, the open/closed state display unit 56a and the battery replacement display unit 58a are turned off.

Next, characteristic functions of the electric power device <NUM> according to the present embodiment will be described with reference to <FIG>. The characteristic functions are functions of accurately calculating the overall SOC of the plurality of detachable batteries <NUM> even when the plurality of detachable batteries <NUM> of different types are housed in the electric power storage device housing units <NUM>. Note that this characteristic functions can also be applied to the SOC calculation processing for a plurality of detachable batteries <NUM> of the same type.

Each of three methods (a first example shown in <FIG>, and second and third examples shown in <FIG>) SOC by the characteristic functions will be described in order.

In the first example of <FIG>, the control unit <NUM> (see <FIG>) calculates the overall SOC of the plurality of detachable batteries <NUM> in consideration of the temperature factor, the deterioration factor, and the specification factor (specification difference value) of each of the four detachable batteries <NUM>. Therefore, the first example can be applied to both the four detachable batteries <NUM> of the same type and the four detachable batteries <NUM> of different types.

Examples of the difference in types of the detachable batteries <NUM> include a difference in capacity or output, and a difference in battery structure. In the present embodiment, even if the detachable batteries <NUM> have the same structure, they are treated as different types of detachable batteries <NUM> when there is a difference in types such as a standard type, a high-output type, or a high-capacity type. In addition, if the detachable batteries <NUM> include a general battery pack and a battery for a hybrid vehicle, they are also treated as different types.

First, in step S1, a driver turns on the ignition switch <NUM>. As a result, an ignition signal is supplied from the ignition switch <NUM> to the control unit <NUM>. Thus, the electric power supply system <NUM> (electric power device <NUM>) in the vehicle <NUM> is activated.

In the next step S2, the communication unit 30a of the control unit <NUM> acquires information of each detachable battery <NUM> from each BMU <NUM> via the CAN <NUM>. The acquired information includes the SOC of each detachable battery <NUM>, a state indicating whether or not each detachable battery <NUM> is loaded in each electric power storage device housing unit <NUM>, and the like. In step S2, the SOC information acquired by the communication unit 30a includes the current charge capacities, the current full charge capacities, and the specification values or initial values of the full charge capacities, of the respective detachable batteries <NUM>.

In the next step S3, the control unit <NUM> determines whether or not each detachable battery <NUM> is accommodated in each electric power storage device housing unit <NUM> based on the information of each detachable battery <NUM> acquired by the communication unit 30a. Further, the control unit <NUM> determines whether the SOC of each detachable battery <NUM> is not <NUM> %.

In step S3, when the detachable batteries <NUM> are accommodated in all the electric power storage device housing units <NUM> and there is no detachable battery <NUM> having the SOC of <NUM> % (step S3: YES), the control unit <NUM> proceeds to the process of step S4.

In step S4, the control unit <NUM> confirms the type of each detachable battery <NUM>, based on the information of each detachable battery <NUM> acquired in step S2.

In step S5, the communication unit 30a of the control unit <NUM> acquires the temperature factor, the deterioration factor, and the specification factor of each detachable battery <NUM> from each BMU <NUM> via the CAN <NUM>. The specification factor is a factor relating to a specification difference of the own detachable battery <NUM> with respect to a reference detachable battery <NUM> when an arbitrary detachable battery <NUM> is set as the reference detachable battery. Therefore, the specification factor is a kind of specification difference value. For example, when a capacity of a reference detachable battery <NUM> is <NUM> Wh, the specification factor of the detachable battery <NUM> having a capacity of <NUM> Wh is <NUM> (<NUM>/<NUM> = <NUM>). Also, the specification factor of the detachable battery <NUM> having a capacity of <NUM> Wh volume is <NUM> (<NUM>/<NUM> = <NUM>).

In step S6, the control unit <NUM> calculates a sum FCC of the full charge capacities of the respective detachable batteries <NUM>, based on the information of the detachable batteries <NUM> acquired by the communication unit 30a from each BMU <NUM> via the CAN <NUM>. In this case, the sum FCC of the full charge capacities is a sum FCC0 of the specification values or the initial values of the full charge capacities of the respective detachable batteries <NUM> if each detachable battery <NUM> is not deteriorated. When each detachable battery <NUM> is deteriorated, the sum FCC of the full charge capacities is the sum of the full charge capacities at the present time. That is, the sum FCC of the full charge capacities is expressed by a following expression (<NUM>). Note that ∑ is a mathematical symbol indicating the sum.

In step S7, the control unit <NUM> calculates a sum RC of the current remaining capacities (current charge capacities) of the respective detachable batteries <NUM>, based on the information of the detachable batteries <NUM> acquired by the communication unit 30a from each BMU <NUM> via the CAN <NUM>. In this case, the control unit <NUM> calculates the sum RC of the current charge capacities, based on the full charge capacities and the current SOCs of the respective detachable batteries <NUM>. Alternatively, the control unit <NUM> may calculate the sum RC of the current charge capacities, based on the SOC, the temperature factor, the deterioration factor and the specification factor, of each detachable battery <NUM>. Further, the control unit <NUM> may calculate the sum RC of the current charge capacities, based on a time integration value of the current (charging current, discharging current) for charging and discharging each detachable battery <NUM>.

Therefore, the sum RC of the current charge capacities is expressed by any one of the following expressions (<NUM>) to (<NUM>). <MAT> <MAT> <MAT>.

In step S8, the control unit <NUM> divides the sum RC of the current charge capacities of the respective detachable batteries <NUM> by the sum FCC of the full charge capacities of the respective detachable batteries <NUM>. Thus, RSOC, which is the overall SOC of the respective detachable batteries <NUM>, is calculated. In this case, RSOC is expressed by the following expression (<NUM>).

In step S9, the control unit <NUM> controls each BMU <NUM> and each DC/DC converter <NUM> based on the calculated RSOC and the like.

In this case, the control unit <NUM> assigns IDs to the respective BMUs <NUM> (detachable batteries <NUM>), to transmit and receive information via each CAN <NUM>. The control unit <NUM> outputs the assigned IDs from the communication unit 30a to the CAN <NUM>. Further, based on the RSOC or the like, the control unit <NUM> outputs control commands for controlling the BMUs <NUM> to which IDs have been assigned, from the communication unit 30a to the CAN <NUM>. Thus, each of the BMUs <NUM> causes a current to flow from the detachable battery <NUM> to the DC/DC converter <NUM>, based on the control command acquired from the CAN <NUM>.

Further, the control unit <NUM> adjusts the current command values for the respective DC/DC converters <NUM> in consideration of the RSOC. The control unit <NUM> outputs the respective current command values which have been adjusted, from the communication unit 30a to the CAN <NUM>. Each of the DC/DC converters <NUM> converts the voltage output from the detachable battery <NUM> based on the current command value acquired from the CAN <NUM>.

In step S10, the control unit <NUM> sets the display content of the display device <NUM> according to the calculated RSOC and the like as a display control signal. The control unit <NUM> outputs the set display control signal from the communication unit 30a to the CAN <NUM>. Accordingly, the display device <NUM> carries out screen displays in <FIG> and the like, based on the display control signal and the like acquired by the communication unit 38a via the CAN <NUM>.

In step S11, when the process of steps S2 to S11 is executed again (step S11: YES), the control unit <NUM> returns to step S2. Alternatively, after the driver confirms the display content of the display device <NUM> in step S10, the driver may drive the vehicle <NUM> in step S12. Thus, the vehicle <NUM> can be moved. In this case, after step S12, the determination processing of step S11 is executed.

The second example relates to a calculation process of the overall SOC of the respective detachable batteries <NUM> in a case where any of the electric power storage device housing units <NUM> does not house a detachable battery <NUM>, or in a case where any of the detachable batteries <NUM> has an SOC of <NUM> % even if each electric power storage device housing unit <NUM> houses a detachable battery <NUM>.

In this case, the number of detachable batteries <NUM> to supply electric power is decreased. Therefore, the load per detachable battery <NUM> increases. Also, the overall output of the plurality of detachable batteries <NUM> is decreased. As a result, the overall capacity of the plurality of detachable batteries <NUM> is rather decreased. This will be specifically described with reference to <FIG>.

<FIG> shows a relationship between the voltage and the overall dischargeable capacity of the plurality of detachable batteries <NUM> of a standard type. A solid line indicates a result when four detachable batteries <NUM> are mounted in the vehicle <NUM>. When the four detachable batteries <NUM> in a full charge state are mounted in the vehicle <NUM>, the overall dischargeable capacity of the four detachable batteries <NUM> is <NUM> %. Further, the four detachable batteries <NUM> are subjected to 1C discharge.

Further, in <FIG>, a broken line indicates a case where two detachable batteries <NUM> are mounted in the vehicle <NUM>. In the case of the broken line, when the two detachable batteries <NUM> in a full charge state are mounted in the vehicle <NUM>, the overall dischargeable capacity of the two detachable batteries <NUM> is reduced to <NUM> % compared to the total dischargeable capacity (<NUM> %) of the four detachable batteries <NUM>. In addition, compared to the case of four detachable batteries <NUM>, the load per detachable battery increases in the case of two detachable batteries <NUM>. Thus, the two detachable batteries <NUM> are subjected to 2C discharge at a high discharge rate. For example, using the four detachable batteries <NUM> (solid line) or the two detachable batteries <NUM> (broken line), when the same output (10kW) is produced, the four detachable batteries <NUM> have a closed circuit voltage of about <NUM> V and a discharge current of about <NUM> A (<NUM> A per battery). In the case of two detachable batteries <NUM>, a closed circuit voltage drops to <NUM> V. In the case of two detachable batteries <NUM>, a discharge current increases to <NUM> A (<NUM> A per battery).

<FIG> shows a relationship between the voltage and the overall dischargeable capacity of the plurality of detachable batteries <NUM> of a high-output type. A solid line indicates a case when four detachable batteries <NUM> are mounted in the vehicle <NUM>. Also in <FIG>, when the four detachable batteries <NUM> in a full charge state are mounted in the vehicle <NUM>, the overall dischargeable capacity of the four detachable batteries <NUM> is <NUM> %. The four detachable batteries <NUM> are subjected to 1C discharge.

Further, in <FIG>, a broken line indicates a case where two detachable batteries <NUM> are mounted in the vehicle <NUM>. With the high-output type, in the case of the broken line, when the two detachable batteries <NUM> in a full charge state are mounted in the vehicle <NUM>, the overall dischargeable capacity of the two detachable batteries <NUM> is reduced to <NUM> % compared to the total dischargeable capacity (<NUM> %) of the four detachable batteries <NUM>. Therefore, also in <FIG>, compared to the case of four detachable batteries <NUM>, the load per detachable battery <NUM> is increased in the case of two detachable batteries <NUM>. Thus, the two detachable batteries <NUM> are subjected to 2C discharge. However, in comparison with the result of the standard type detachable battery <NUM> (broken line in <FIG>), the decrease in dischargeable capacity is suppressed to <NUM> % in the result indicated by the broken line in <FIG>.

Therefore, in the second example, the overall SOC of the respective detachable batteries <NUM> is calculated in consideration of an increase in the load of the detachable batteries <NUM> due to such a decrease in the number. In the following description of the second embodiment, a case where two detachable batteries <NUM> of the same type are mounted in the vehicle <NUM> will be described.

More specifically, in step S2 of <FIG>, when the four detachable batteries <NUM> are not housed in the electric power storage device accommodating unit electric power storage device housing unit <NUM> or when the SOC of at least one detachable battery <NUM> among the detachable batteries <NUM> is <NUM> % (step S2: NO), the control unit <NUM> proceeds to step S21 in <FIG>.

In step S21, the control unit <NUM> confirms the number of the detachable batteries <NUM> mounted in the vehicle <NUM> and the types of the detachable batteries <NUM>, based on the information of the detachable batteries <NUM> acquired by the communication unit 30a.

In step S22, the communication unit 30a of the control unit <NUM> acquires the temperature factor, the deterioration factor, and the specification factor of each detachable battery <NUM> from each BMU <NUM> via the CAN <NUM> in the same manner as in step S4. When the detachable battery <NUM> is not housed in the electric power storage device housing unit <NUM>, the above information cannot be acquired. Even when the detachable battery <NUM> is housed in the electric power storage device housing unit <NUM>, if the SOC is <NUM> %, the communication unit 30a of the control unit <NUM> acquires information indicating that the SOC is <NUM> %.

In step S23, the control unit <NUM> calculates a sum FCC of the full charge capacities of the detachable batteries <NUM> in the same manner as in step S6. In this case, the control unit <NUM> calculates the sum FCC of the full charge capacities of the two detachable batteries <NUM>.

In step S24, the control unit <NUM> calculates the sum RC0 of the current charge capacities of the two housed detachable batteries <NUM>. Next, the control unit <NUM> determines a correction factor corresponding to the number and type of the detachable batteries <NUM> mounted in the vehicle <NUM>.

Here, the correction factor is, for example, a numerical value corresponding to a decrease in dischargeable capacity caused by a decrease in the number of detachable batteries <NUM> mounted in the vehicle <NUM> from four to two. More specifically, for the standard detachable battery <NUM> of <FIG>, the correction factor is <NUM>, which corresponds to a <NUM> % reduction. In addition, in the case of the high-output type detachable battery <NUM> in <FIG>, the correction factor is <NUM> corresponding to a decrease of <NUM> %.

In step S25, the control unit <NUM> calculates the sum RC of the current charge capacities of the detachable batteries <NUM> in consideration of the correction factor. That is, the control unit <NUM> calculates the sum RC by using the following expression (<NUM>).

In step S8 of <FIG> after step S25, the control unit <NUM> calculates the RSOC from the expression (<NUM>) using the sum RC of the current charge capacities calculated from the expression (<NUM>) and the sum FCC of the full charge capacities.

A third example differs from the second example in the following points. In the third example, even when the number of the detachable batteries <NUM> mounted in the vehicle <NUM> is small, the sum of the full charge capacities of the four detachable batteries <NUM> is set as the sum FCC of the full charge capacities. On the other hand, in the third example, the remaining capacities corresponding to the number of the mounted detachable batteries <NUM> is set as the sum RC of the current charge capacities.

In this case, in step S23, the control unit <NUM> calculates the sum FCC of the full charge capacities of the four detachable batteries <NUM> in the same manner as in step S6.

After step S23, the control unit <NUM> proceeds to step S31. The control unit <NUM> calculates the sum RC of the current charge capacities in consideration of the number of detachable batteries <NUM> that are not mounted in the vehicle <NUM>. That is, the control unit <NUM> calculates the sum of the current charge capacities of the two detachable batteries <NUM> mounted in the vehicle <NUM> as the sum RC.

In step S8 of <FIG> after step S31, the control unit <NUM> calculates the RSOC from expression (<NUM>) using the sum FCC of the full charge capacities calculated in step S23 and the sum RC of the current charge capacities calculated in step S31.

In each of the above examples, the case where the sum RC of the current charge capacities is calculated after calculating the sum FCC of the full charge capacities has been described (step S6 → step S7; step S23 → step S25 or step S31). In the present embodiment, it is also possible to first calculate the sum RC of the current charge capacities. Thereafter, in the present embodiment, it is possible to calculate the sum FCC of the full charge capacities (step S7 → step S6; step S25 or step S31 → step S23).

In each of the above examples, the control unit <NUM> acquires the full charge capacities and the current charge capacities in step S2. In the present embodiment, however, the control unit <NUM> may acquire the current charge capacities and the full charge capacities in step S5 or S22. Alternatively, in step S2, the control unit <NUM> may acquire either the full charge capacities or the current charge capacities. In step S5 or S22, it is also possible for the control unit <NUM> to acquire the charge capacities that were not acquired.

In the present embodiment, the control unit <NUM> may acquire either the full charge capacities or the current charge capacities and then calculate the sum of the acquired charge capacities. In this case, the control unit <NUM> can then execute a process to acquire the other charge capacities and calculate the sum of the other charge capacities acquired.

As described above, in the present embodiment, it should be noted that the processing order in the control unit <NUM> is not limited to the order described in the first to third examples.

As described above, according to the present embodiment, the electric power device <NUM> including the plurality of detachable batteries (electric power storage units) 16a to 16d (<NUM>) that are chargeable and dischargeable is provided, and the control unit <NUM> (state of charge calculation unit) is configured to calculate the RSOC which is the overall SOC (state of charge) of the plurality of detachable batteries 16a to 16d, based on the sum FCC of full charge capacities of the respective detachable batteries 16a to 16d and the sum RC of current charge capacities of the respective detachable batteries 16a to 16d.

Further, according to the present embodiment, the display device <NUM> includes the communication unit 38a (receiving unit) configured to receive the overall SOC (RSOC) of the plurality of detachable batteries 16a to 16d from the electric power device <NUM> is provided, and the display device <NUM> is configured to display the received RSOC.

Further, according to the present embodiment, the state of charge calculation method for the electric power device <NUM> including the plurality of detachable batteries 16a to 16d (<NUM>) that are chargeable and dischargeable is provided. The method includes the steps of acquiring full charge capacities of the plurality of detachable batteries 16a to 16d, respectively (step S2), calculating the sum FCC of the plurality of full charge capacities (step S6, step S23), acquiring current charge capacities of the plurality of detachable batteries 16a to 16d, respectively (step S2), calculating the sum RC of the plurality of current charge capacities (step S7, step S25, step S31), and calculating the RSOC based on the sum FCC of the full charge capacities and the sum RC of the current charge capacities (step S8).

Furthermore, according to the present embodiment, the program is provided. The program causes the control unit <NUM> of the electric power device <NUM> as a computer to execute the steps of acquiring full charge capacities of the plurality of detachable batteries 16a to 16d, respectively (step S2), calculating the sum FCC of the plurality of full charge capacities (step S6, step S23), acquiring current charge capacities of the plurality of detachable batteries 16a to 16d, respectively (step S2), calculating the sum RC of the plurality of current charge capacities (step S7, step S25, step S31), and calculating the RSOC based on the sum FCC of the full charge capacities and the sum RC of the current charge capacities (step S8).

Further still, according to the present embodiment, the storage unit 30b (storage medium) is provided. The storage unit 30b stores the above-described program.

As described above, by using the sum FCC of the full charge capacities of the respective detachable batteries 16a to 16d and the sum RC of the current charge capacities of the respective detachable batteries 16a to 16d, it is possible to accurately calculate the RSOC as the overall SOC of the plurality of detachable batteries 16a to 16d. Further, it is possible to display the RSOC obtained in this way.

In this case, each of the full charge capacities is acquired based on the specification value or the initial value related to the full charge capacity of each of the detachable batteries 16a to 16d. Accordingly, it is possible to calculate the RSOC more accurately.

Further, each of the full charge capacities is acquired based on at least one of a temperature or a degree of deterioration of each of the detachable batteries 16a to 16d. Accordingly, it is possible to calculate the RSOC more accurately, based on a current status of each of the detachable batteries 16a to 16d.

Furthermore, if any of the plurality of the detachable batteries 16a to 16d has a specification difference, the full charge capacity thereof is acquired based on a specification difference value (e.g., specification factor) set according to the specification difference. Accordingly, it is possible to accurately calculate the RSOC, considering the specification difference of each of the detachable batteries 16a to 16d.

Further still, each of the current charge capacities is acquired based on an integrated value of an electric current that charges and discharges each of the detachable batteries 16a to 16d. Accordingly, it is possible to calculate the RSOC correctly.

Further, the control unit <NUM> may calculate the RSOC by dividing the sum RC of the current charge capacities by the sum FCC of the full charge capacities. Accordingly, it is possible to calculate the RSOC easily.

Furthermore, as in the second example, the control unit <NUM> corrects the sum RC of the current charge capacities in accordance with the number and the types of the plurality of detachable batteries 16a to 16d. Accordingly, it is possible to calculate the most suitable RSOC, considering decreased discharge capacity due to the decrease in the number of the plurality of detachable batteries 16a to 16d.

Further still, as in the third example, the control unit <NUM> corrects the sum RC of the current charge capacities in accordance with the number of the detachable batteries 16a to 16d having the current charge capacity of <NUM> (zero). Also in this case, it is possible to calculate the most suitable RSOC, considering decreased discharge capacity due to the decrease in the number of the plurality of detachable batteries 16a to 16d.

Further, the plurality of detachable batteries 16a to 16d are electric power storage devices that are attachable to and detachable from the vehicle <NUM>, and the control unit <NUM> is a control device mounted in the vehicle <NUM>. Accordingly, the electric power device <NUM> can be suitably applied as the electric power supply system <NUM> of the vehicle <NUM>.

Further, the electric power device <NUM> further includes the communication unit 30a (transmission unit) configured to transmit the RSOC calculated by the control unit <NUM> to the display device <NUM>. Accordingly, the display device <NUM> can receive the RSOC by the communication unit 38a and display the received RSOC reliably.

Claim 1:
An electric power device (<NUM>) including a plurality of electric power storage units (<NUM>, 16a to 16d) that are chargeable and dischargeable, the electric power device comprising:
a state of charge calculation unit (<NUM>) configured to calculate an overall state of charge (RSOC) of the plurality of electric power storage units, based on a sum (FCC) of full charge capacities of the respective electric power storage units and a sum (RC) of current charge capacities of the respective electric power storage units,
characterized in that if any of the plurality of electric power storage units has a specification difference, the full charge capacity thereof is acquired based on a specification difference value set according to the specification difference.