WO2019176368A1

WO2019176368A1 - Power transmission device

Info

Publication number: WO2019176368A1
Application number: PCT/JP2019/003781
Authority: WO
Inventors: 宮崎　英樹; 井戸　寛
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2018-03-14
Filing date: 2019-02-04
Publication date: 2019-09-19
Also published as: JP2021083135A

Abstract

The present invention enables a charging process to be performed in accordance with the presence/absence of charging records. This power transmission device for feeding power to a power reception device having a battery is provided with: an initial charge determination unit which receives identification information from the power reception device and determines whether or not said power reception device has been charged in the past; and a power transmission control unit which, in the case when the initial charge determination unit determines that charging has taken place in the past, executes a first power transmission process with respect to the power reception device, and, in the case when the initial charge determination unit determines that charging has not taken place in the past, executes a second power transmission process with respect to the power reception device.

Description

Power transmission equipment

The present invention relates to a power transmission device.

In recent years, in an electric vehicle or the like, a wireless power feeding system that feeds power wirelessly from a power transmitting device provided on the ground side to a power receiving device provided on the vehicle side is being realized. In such a wireless power feeding system, a wireless power feeding technique using magnetic field resonance or magnetic field induction has attracted attention. In magnetic field induction, a magnetic field (magnetic flux) is generated by flowing an alternating current through a coil provided in a ground-side power transmission device, and this magnetic field is received by a coil provided in a vehicle-side power receiving device to generate an alternating current. By doing so, wireless power feeding from the power transmitting device to the power receiving device is realized. On the other hand, magnetic resonance is the same as magnetic field induction in that a coil is provided in each of the power transmission device and the power reception device, but by matching the frequency of the current flowing in the coil of the power transmission device with the resonance frequency of the coil of the power reception device, Resonance is generated between the power transmission device and the power reception device. As a result, the coil of the power transmission device and the coil of the power reception device are magnetically coupled to achieve highly efficient wireless power feeding.

Regarding the wireless power feeding technology described above, the following Patent Document 1 is known. Patent Document 1 discloses a power supply stand that has an in-vehicle battery and supplies electric power to the in-vehicle battery of a vehicle that travels by an electric drive unit that uses the in-vehicle battery as a power source, and is charged by a commercial power source. A power failure detection means for detecting a power failure of a commercial power supply, a power supply mode for supplying power to the in-vehicle battery, a normal power supply mode for supplying power to the in-vehicle battery mainly using a commercial power supply, and the power storage unit First switching means for switching to a power failure power supply mode for feeding power to a vehicle-mounted battery, and control means for switching the first switching means to the power failure power supply mode when a power failure is detected by the power failure detection means. A power supply stand is disclosed.

JP 2012-50291 A

Since there are countless combinations of power transmission devices and power reception devices, there is room for improvement in the charging control method.

The power transmission device according to the first aspect of the present invention is a power transmission device that feeds power to a power reception device having a battery, receives identification information from the power reception device, and determines whether or not charging has been performed previously. When the first determination unit determines that the charging has been performed before, the first power transmission process is performed on the power receiving device, and when the first determination unit determines that the charging is not performed before, the power receiving device And a power transmission control unit that executes the power transmission process 2.

According to the present invention, a charging process can be performed according to the presence or absence of charging results.

1 is a diagram illustrating a configuration of a wireless power feeding system according to an embodiment of the present invention. It is a figure which shows the structural example of the power receiving apparatus which concerns on one Embodiment of this invention. It is a figure which shows the temperature characteristic of the internal resistance in a battery. It is a figure which shows an example of the relationship between SOC of a battery, and OCV. It is a figure which shows the time change of the charging current in intermittent charge. It is a flowchart showing operation | movement of a power transmission control part.

Hereinafter, embodiments of a power receiving device according to the present invention will be described with reference to the drawings.

(Configuration of wireless power feeding system 1)
FIG. 1 is a diagram showing a configuration of a wireless power feeding system 1 according to an embodiment of the present invention. A wireless power feeding system 1 shown in FIG. 1 is used in wireless power feeding to a vehicle such as an electric vehicle, and includes a power transmission device 100 installed on the ground side near the vehicle and a vehicle side device. The vehicle-side devices are the power receiving device 200, the battery 300, the load 400, and the battery monitoring device 500 that are respectively mounted on the vehicle. Although FIG. 1 shows only one vehicle-side device, the power transmission device 100 can be used in combination with various vehicle-side devices.

The power transmission device 100 includes a power transmission control unit 110, a communication unit 120, an AC power source 130, a power conversion unit 140, a storage unit 150, and a primary coil L1. The power transmission control unit 110 controls the power transmission apparatus 100 as a whole by controlling the operations of the communication unit 120 and the power conversion unit 140.

The communication unit 120 performs wireless communication with the communication unit 220 included in the power receiving device 200 under the control of the power transmission control unit 110. Various information necessary for wireless power feeding is exchanged between the power transmitting apparatus 100 and the power receiving apparatus 200 by wireless communication between the communication unit 120 and the communication unit 120. For example, information such as the frequency of the alternating current flowing through the primary coil L1, that is, the frequency of the alternating magnetic field emitted from the primary coil L1, is transmitted from the communication unit 120 to the communication unit 220. In addition, information such as the state of charge (SOC) and deterioration state of battery 300 and the allowable current during charging is transmitted from communication unit 220 to communication unit 120.

AC power supply 130 is a commercial power supply, for example, and supplies predetermined AC power to the power conversion unit 140. The power conversion unit 140 outputs an alternating current having a predetermined frequency and current value to the primary coil L <b> 1 using the alternating current power supplied from the alternating current power supply 130 under the control of the power transmission control unit 110. Primary coil L1 is installed on the ground side located under the vehicle, and emits an alternating magnetic field corresponding to the alternating current flowing from power conversion unit 140 toward the vehicle. Thereby, wireless power feeding to the vehicle is performed.

The storage unit 150 is a non-volatile readable / writable storage device such as a flash memory. The storage unit 150 stores an ID of the power receiving apparatus 200 that has been charged before and a maximum capacity Qmax described later in association with each other. The ID of the power receiving device 200 will be described later. The power transmission control unit 110 writes the ID and the maximum capacity Qmax of the new power receiving device 200 in the storage unit 150, and the power transmission control unit 110 is written in the storage unit 150, that is, the power receiving device 200 stored in the storage unit 150. ID and maximum capacity Qmax are read.

The power receiving apparatus 200 includes a power reception control unit 210, a communication unit 220, an alternating current detection unit 230, a drive control unit 240, a power conversion unit 250, a secondary coil L2, a resonance coil Lx, and a resonance capacitor Cx. The resonance coil Lx and the resonance capacitor Cx are connected to the secondary coil L2, and constitute a resonance circuit together with the secondary coil L2. The resonance frequency of the resonance circuit is determined according to the inductances of the secondary coil L2 and the resonance coil Lx and the capacitance value of the resonance capacitor Cx. Note that the resonant coil Lx and the resonant capacitor Cx may each be composed of a plurality of elements. Further, part or all of the resonance coil Lx may be substituted by the inductance of the secondary coil L2.

The power reception control unit 210 controls the power reception apparatus 200 as a whole by controlling the operations of the communication unit 220 and the drive control unit 240. The communication unit 220 performs wireless communication with the communication unit 120 included in the power transmission device 100 under the control of the power reception control unit 210, and stores various types of information as described above exchanged between the power transmission device 100 and the power reception device 200. Send and receive. Information such as the frequency of the alternating current flowing through the primary coil L1 received by the communication unit 220 is output from the communication unit 220 to the power reception control unit 210.

The power reception control unit 210 includes a nonvolatile storage device (not shown) such as a flash memory. This storage device stores the ID of the power receiving device 200. The ID is unique to each power receiving apparatus 200, and it is desirable that the value changes when the battery 300 is replaced. For example, the power reception control unit 210 uses a combination of the identification information of the power reception device 200 and the identification information of the battery 300 as the ID of the power reception device 200. The identification information of the power receiving device 200 is, for example, the manufacturing number of the power receiving device 200 or the MAC address of the communication unit 220, and the identification information of the battery 300 is, for example, the manufacturing number of the battery 300.

The alternating current detection unit 230 detects the alternating current flowing through the resonance circuit including the secondary coil L2 when the secondary coil L2 receives the alternating magnetic field emitted from the primary coil L1. Then, an AC voltage whose frequency and amplitude change according to the detected AC current is generated and output to the drive control unit 240. The drive control unit 240 can acquire the frequency and magnitude of the alternating current flowing through the resonance circuit based on the alternating voltage input from the alternating current detection unit 230.

The drive control unit 240 controls the switching operations of the plurality of switching elements included in the power conversion unit 250 under the control of the power reception control unit 210. At this time, the drive control unit 240 changes the timing of the switching operation of each switching element based on the alternating current flowing through the resonance circuit detected by the alternating current detection unit 230. A specific method for changing the timing of the switching operation will be described later.

The power conversion unit 250 has a plurality of switching elements, and controls the AC current flowing through the resonance circuit and rectifies by switching each of the plurality of switching elements, thereby converting AC power to DC power. Do. The power conversion unit 250 is connected to a chargeable / dischargeable battery 300, and the battery 300 is charged using DC power output from the power conversion unit 250. Note that a smoothing capacitor C0 for smoothing an input voltage to the battery 300 is connected between the power conversion unit 250 and the battery 300.

A load 400 is connected to the battery 300. The load 400 provides various functions related to the operation of the vehicle using the DC power charged in the battery 300. The load 400 includes, for example, an AC motor for driving a vehicle, an inverter that converts DC power of the battery 300 into AC power, and supplies the AC power to the AC motor.

The battery monitoring device 500 includes a sensor and a nonvolatile storage device. The battery monitoring device 500 is connected to the battery 300 and measures various information of the battery 300 using a sensor. For example, the battery monitoring device 500 measures the voltage, temperature, and internal resistance of the battery 300 and outputs the measured values to the drive control unit 240. The drive control unit 240 transmits the measurement value input from the battery monitoring device 500 to the power reception control unit 210 and further transmits the measured value to the power transmission device 100 via the communication unit 220. However, the battery monitoring apparatus 500 may directly output the measurement value to the power reception control unit 210. That is, the route through which the measurement value measured by the battery monitoring device 500 is transmitted to the power reception control unit 210 is arbitrary, and the measurement value may be transmitted to the power reception control unit 210 and finally transmitted to the power transmission device 100.

Further, the battery monitoring device 500 stores the reference internal resistance value R0 and the maximum capacity Qmax as parameters indicating the deterioration state of the battery 300. The reference internal resistance value R0 is an internal resistance value of the battery 300 at a reference temperature, for example, 25 degrees Celsius. The internal resistance of the battery 300 increases and decreases under the influence of temperature, but even if the influence of temperature is excluded, the internal resistance value increases due to deterioration. The maximum capacity Qmax is the maximum power capacity that can be stored in the battery 300 at a certain time. The maximum capacity Qmax takes a maximum value when the battery 300 is manufactured, and decreases due to deterioration. In other words, the maximum capacity Qmax is a parameter indicating the deterioration of the battery 300. However, the change in the maximum capacity Qmax is gradual, and the change in the time when charging is completed once can be ignored.

Here, a variable (hereinafter, current amount) Qnow indicating the power capacity currently stored in the battery 300 is defined. The current amount Qnow increases / decreases due to charging / discharging. The maximum value of Qnow is Qmax. The battery monitoring device 500 records the measured internal resistance as the reference internal resistance value R0 when the measured temperature of the battery 300 is the reference temperature, and then measures it after a predetermined time, for example, one week or more has elapsed since recording. When the temperature of the battery 300 is the reference temperature, the measured internal resistance value is stored as a new reference internal resistance value R0. The battery monitoring device 500 records, that is, updates, the maximum capacity Qmax transmitted from the power transmission device 100 as a new value, as will be described later. However, the power receiving apparatus 200 may further update the value of the maximum capacity Qmax by other means.

(Details of power receiving device 200)
Details of the power receiving device 200 in the wireless power feeding system 1 of FIG. 1 will be described. FIG. 2 is a diagram illustrating a configuration example of the power receiving device 200 according to an embodiment of the present invention.

As shown in FIG. 2, the alternating current detection unit 230 is configured using, for example, a transformer Tr. When the magnetic flux generated by the alternating magnetic field emitted from the primary coil L1 is linked to the secondary coil L2, an electromotive force is generated in the secondary coil L2, and an alternating current i flows through the resonance circuit including the secondary coil L2. When this alternating current i flows through the primary coil of the transformer Tr, an alternating voltage Vg whose frequency and amplitude change according to the alternating current i is generated at both ends of the secondary coil of the transformer Tr. Thereby, the alternating current detection part 230 can detect the alternating current i. Note that the AC current detection unit 230 may be configured by using a device other than the transformer Tr as long as the AC current i flowing through the resonance circuit can be detected.

The power conversion unit 250 includes two MOS transistors (MOSFETs) Q1 and Q2 connected in series. The MOS transistors Q1 and Q2 perform a switching operation for switching between the source and the drain from the conductive state to the disconnected state or from the disconnected state to the conductive state in accordance with the gate drive signal from the drive control unit 240. By this switching operation, the MOS transistor Q1 can function as an upper arm switching element, and the MOS transistor Q2 can function as a lower arm switching element. A resonance circuit including the secondary coil L2 is connected to the connection point O between the MOS transistors Q1 and Q2 and the source terminal of the MOS transistor Q2. Therefore, the AC current i flowing through the resonance circuit can be controlled and rectified by switching the MOS transistors Q1 and Q2 at appropriate timings.

2 exemplifies the power conversion unit 250 having a half-bridge configuration using two MOS transistors Q1 and Q2 as switching elements, but as a power conversion unit 250 having a full-bridge configuration using four MOS transistors as switching elements. Also good. In the following, an example of operation by the power converter 250 having the half-bridge configuration shown in FIG. 2 will be described, but the basic operation is the same even when the full-bridge configuration is used.

The drive control unit 240 includes a voltage acquisition unit 241, a drive signal generation unit 243, and a gate drive circuit 244.

The voltage acquisition unit 241 acquires the AC voltage Vg output from the AC current detection unit 230 (transformer Tr) and outputs the AC voltage Vg to the drive signal generation unit 243.

The drive signal generation unit 243 receives the basic drive signal Sr from the power reception control unit 210 in addition to the AC voltage Vg acquired by the voltage acquisition unit 241. The basic drive signal Sr is an AC signal that is output from the drive control unit 240 to the power conversion unit 250 and is a source of a gate drive signal that controls the switching operation of the MOS transistors Q1 and Q2, and the frequency thereof is the primary power transmission device 100. It is determined according to the frequency of the current flowing through the coil L1. Specifically, when the communication unit 220 receives information representing the frequency f of the alternating current flowing through the primary coil L1 of the power transmission device 100 from the communication unit 120, the communication unit 220 outputs the information to the power reception control unit 210. When the information on the frequency f is input from the communication unit 220, the power reception control unit 210 generates a basic drive signal Sr corresponding to the frequency f and outputs it to the drive control unit 240. The basic drive signal Sr is, for example, a combination of two rectangular waves corresponding to the MOS transistors Q1 and Q2, respectively, and has an H level corresponding to ON (conducting state) and an L level corresponding to OFF (disconnected state). Are alternately repeated at the frequency f. However, a predetermined protection period is provided between the H levels of the two rectangular waves so that the MOS transistors Q1 and Q2 are not turned on simultaneously.

The drive signal generation unit 243 adjusts the phase of the basic drive signal Sr input from the power reception control unit 210 based on the AC voltage Vg input from the power reception control unit 210, and generates the charge drive signal Sc. Then, the generated charge drive signal Sc is output to the gate drive circuit 244.

The gate drive circuit 244 outputs a gate drive signal based on the charge drive signal Sc input from the drive signal generation unit 243 to the gate terminals of the MOS transistors Q1 and Q2, respectively, and causes the MOS transistors Q1 and Q2 to perform a switching operation. Thus, in the power conversion unit 250, the MOS transistors Q1 and Q2 function as switching elements, respectively, and control of the alternating current i flowing in the resonance circuit according to the alternating magnetic field emitted from the primary coil L1, or the alternating current power to the direct current power. Conversion to

The power receiving device 200 of the present embodiment can charge the battery 300 by receiving wireless power feeding from the power transmitting device 100 by performing the operation described above.

(Temperature characteristics)
FIG. 3 is a diagram showing the temperature characteristics of the internal resistance in the battery 300, that is, the relationship between the temperature T of the battery 300 and the magnification of the internal resistance. However, in FIG. 3, the above-mentioned reference temperature of 25 degrees is set as a reference, that is, 1 time. As shown in FIG. 3, the internal resistance of the battery 300 increases as the temperature decreases. And it is 5 times at 0 degrees, 10 times at -10 degrees, and 20 times at -25 degrees. For example, when the internal resistance Rx at 25 degrees of a certain battery 300 is 1 mΩ, when the temperature of the battery 300 decreases to −25 degrees, the internal resistance Rx is 20 times 20 mΩ. Hereinafter, the temperature characteristic of the internal resistance is expressed as a function K (T). That is, in the above example, K (−25) = 20.

(Relationship between SOC and OCV)
FIG. 4 is a diagram illustrating an example of the relationship between the SOC and the OCV of the battery 300. When the SOC shown on the horizontal axis changes from 0% to 100%, the change in the OCV shown on the vertical axis will be described. Since FIG. 4 shows the change tendency as an example, specific numerical values of OCV are not shown. The OCV increases monotonously with the increase in SOC, but the gain, that is, the rate at which the OCV increases with respect to the increase in SOC is not constant. For example, in the example shown in FIG. 4, the gain of SOC less than 20% and SOC 80% or more is large, and OCV hardly changes in the range of SOC of 20% to 80%. In the present embodiment, a region where the gain is high and the SOC is high, that is, a region where the SOC in the example shown in FIG. 4 is 80% or more is referred to as a “high gain region”.

(Intermittent charging)
FIG. 5 is a diagram illustrating a change in charging current with time in intermittent charging. In the intermittent charging in this embodiment, as shown in FIG. 5, a certain current ia is applied for a time ton, then interrupted for a time toff, and applied again for a time ton. The following repeats this. The time ton and the time toff can be set arbitrarily, but in the present embodiment, the lengths of both are the same. That is, the time intervals from t0 to t9 shown in FIG. 5 are equal.

The power supplied to the battery 300 from time t0 to time t1 is represented by the product of current and time. Therefore, if an arbitrary timing between time t1 and time t2 is time t100, and an arbitrary timing between time t7 and time t8 is time t200, electric power P supplied to battery 300 from time t100 to time t200 Is 3 × (ia × ton).

(Evaluation of deterioration)
A method for evaluating deterioration performed by the power transmission control unit 110 will be described. The relationship among the SOC, the current amount Qnow, and the maximum capacity Qmax is as shown in Equation 1.
SOC = Qnow / Qmax (1)
Therefore, considering the influence when the current amount Qnow is changed in Equation 1, if the change amount of the current amount Qnow is expressed by ΔQnow and the change amount of the SOC is expressed by ΔSOC, Equation 2 is obtained.
ΔSOC = ΔQnow / Qmax (2)

Here, when Expression 2 is modified so that the maximum capacity Qmax is singly on the left side, Expression 3 is obtained.
Qmax = ΔQnow / ΔSOC (3)

For example, when intermittent charging is performed by supplying a current as shown in FIG. 5, if the difference between time t100 and time t200 is evaluated, ΔQnow is 3 × (ia × ton) as described above. Further, the OCV is measured at each of time t100 and time t200, and ΔSOC is calculated from the known SOC-OCV correlation diagram shown in FIG. 4 and the increment of OCV, that is, ΔOCV. That is, since the values of the two variables shown on the right side of Equation 3 are obtained, the maximum capacity Qmax can be calculated. As described above, the maximum capacity Qmax is a parameter indicating the deterioration of the battery 300.

(Overview of charging)
It is not easy for the power transmitting apparatus 100 to determine whether the connected power receiving apparatus 200 is produced according to the standard and whether there is any problem. In particular, since a problem may occur only with a specific combination of the power transmission device 100 and the power reception device 200, it is difficult to confirm in advance. Therefore, the power transmission device 100 determines whether or not the power receiving device 200 to be connected is the first connection. In other words, the power transmitting apparatus 100 determines whether or not the connected power receiving apparatus 200 has a history of charging to full charge using the power transmitting apparatus 100 previously. When it is determined that the battery has been fully charged before, control is performed so that more current flows than in the first connection. Hereinafter, the first connection is referred to as “initial connection”, and the second and subsequent connections are referred to as “repeat connection”.

The power transmission apparatus 100 uses constant current charging, that is, CC charging, and constant voltage charging, that is, CV charging in combination. As described above, since the power transmission device 100 changes the control method depending on whether or not it is the initial connection, the power transmission device 100 has the following four charging modes. That is, CC charging at the first connection, CV charging at the first connection, CC charging at the repeat connection, and CV power reception at the repeat connection. Below, the electric current in each charge is demonstrated. When the amount of current is determined in each charging mode, power transmission device 100 generates an AC magnetic field so that battery 300 is charged with the current in power receiving device 200.

(CC charge at first connection)
The power transmission device 100 performs three operations according to the temperature of the battery 300 in CC charging at the time of initial connection. First, when the temperature of the battery 300 is higher than a predetermined threshold Tz, for example, 0 degrees, the battery 300 is charged with the rated current of the power transmission device 100. Second, when the temperature of the battery 300 is equal to or lower than a predetermined threshold Tz, but is lower than a predetermined threshold Tzz, for example, higher than −20 degrees, the battery 300 is charged at 20 to 30% of the rated current. Third, charging is not performed when the temperature of the battery 300 is equal to or lower than a predetermined threshold value Tzz. In this case, it waits for the temperature of the battery 300 to rise.

(CV charge at the first connection)
In the power transmission device 100, the current Icv supplied to the battery 300 is expressed by the following Equation 4 in CV charging at the time of the initial connection.
Icv = (Vmax−OCVm) / Rcell (4)
However, Vmax is a predetermined target voltage at the end of charging, OCVm is the highest voltage among the non-energized voltages of a plurality of cells constituting the battery 300, and Rcell is the resistance value of the cell with the highest non-conductive voltage. The OCVm and Rcell are measured by the battery monitoring device 500 and transmitted to the power transmission device 100 by communication.

The power transmission device 100 performs intermittent charging as shown in FIG. 5 in CV charging at the time of initial connection, and further evaluates deterioration, that is, calculates the maximum capacity Qmax. However, the value of Icv shown in Equation 4 is used instead of Ia shown in FIG. The time ton and the time toff are, for example, 10 seconds.

(CC charging with repeat connection)
The power transmission device 100 performs three operations according to the temperature of the battery 300 in CC charging with repeat connection. First, when the temperature of the battery 300 is higher than a predetermined threshold Tz, for example, 0 degrees, the battery 300 is charged with the rated current of the power transmission device 100. Secondly, when the temperature of the battery 300 is equal to or lower than a predetermined threshold Tz but is higher than a threshold Tzr determined by the degree of deterioration of the battery 300, the battery 300 is charged with Imax represented by the following formula 5. Thirdly, charging is not performed when the temperature of the battery 300 is equal to or lower than the threshold value Tzr. In this case, it waits for the temperature of the battery 300 to rise.
Imax = (Vb−OCV) / (R0 · K (T)) (5)
However, Vb is the voltage of the battery 300 when energized, OCV is the voltage of the battery 300 when not energized, R0 is the aforementioned reference internal resistance value, and K (T) is a function indicating the aforementioned temperature characteristics.

(CV power reception with repeat connection)
The power transmission device 100 performs CV charging for repeat connection in the same manner as CV charging for the initial connection.

(flowchart)
FIG. 6 is a flowchart showing the operation of the power transmission control unit 110. When the ID of the power receiving device 200 is transmitted from the power receiving device 200 to the power transmitting device 100, the processing illustrated in FIG. 6 is disclosed. The power receiving apparatus 200 may transmit an ID to the power transmitting apparatus 100 based on its own determination, or the power receiving apparatus 200 may transmit an ID to the power transmitting apparatus 100 in response to a transmission command from the power transmitting apparatus 100.

In S301, the power transmission control unit 110 determines whether or not the received ID of the power receiving device 200 is stored in the storage unit 150. When determining that the received ID of the power receiving device 200 is stored in the storage unit 150, the power transmission control unit 110 proceeds to S302, and when determining that the ID of the power receiving device 200 is not stored in the storage unit 150. The process proceeds to S321. In S302, the power transmission control unit 110 acquires the current SOC from the power receiving apparatus 200, and determines whether the SOC is less than 80%. The power transmission control unit 110 proceeds to S303 when determining that the SOC is less than 80%, and proceeds to S311 when determining that the SOC is 80% or more.

In S303, the power transmission control unit 110 acquires the deterioration information, that is, the reference internal resistance value R0 from the power receiving device 200. This deterioration information is used in S306 and S307 described later. In subsequent S <b> 304, the power transmission control unit 110 acquires the battery temperature T from the power receiving device 200. In subsequent S305, the power transmission control unit 110 determines whether or not the battery temperature T acquired in S304 is lower than a predetermined temperature threshold Tz, for example, 0 degrees. The power transmission control unit 110 proceeds to S306 when determining that the battery temperature T is lower than the temperature threshold Tz, and proceeds to S308 when determining that the battery temperature T is equal to or higher than the temperature threshold Tz.

In S306, the power transmission control unit 110 determines whether charging is possible from the deterioration information acquired in S303 and the battery temperature T acquired in S304. Specifically, when R0 / K (T) is smaller than a predetermined threshold value Rz, it is determined that charging is possible, and when it is greater than or equal to the threshold value Rz, it is determined that charging is impossible. The power transmission control unit 110 proceeds to S307 when determining that charging is possible, and returns to S304 when determining that charging is impossible. In the case of returning from S306 to S304, it is expected that the battery temperature T will rise with the passage of time and the judgment in S305 or S306 will change. In step S307, the power transmission control unit 110 performs CC charging for repeat connection using the above-described equation 5, and proceeds to step S309.

In S309, the power transmission control unit 110 acquires the current SOC from the power receiving apparatus 200, and determines whether the SOC is less than 80%. The power transmission control unit 110 returns to S304 when it is determined that the SOC is less than 80%, and proceeds to S311 when it is determined that the SOC is 80% or more. In S <b> 311, the power transmission control unit 110 performs repeat connection CV charging using Equation 4 described above and proceeds to S <b> 312. In S312, the power transmission control unit 110 acquires the current SOC from the power receiving apparatus 200, and determines whether or not the SOC is 100%. The power transmission control unit 110 proceeds to S313 when determining that the SOC is 100%, and returns to S311 when determining that the SOC is less than 100%. In S313, the power transmission control unit 110 calculates the value of the maximum capacity Qmax stored in the storage unit 150 and associated with the identification information of the power receiving apparatus 200 that has completed charging in S311. The value is updated to the value, and the process shown in FIG. 6 ends.

If a negative determination is made in S301, the power transmission control unit 110 executes the processing from S321 onward. Note that the processes of S321, S322, S333, S325, S326, and S328 are the same as the processes of S302, S304, S305, S308, S309, and S312 and will not be described in detail. In S321, the power transmission control unit 110 proceeds to S322 if an affirmative determination is made, and proceeds to S327 if a negative determination is made. In S323 to be executed next to S322, the power transmission control unit 110 proceeds to S323A when making an affirmative determination, and proceeds to S325 when making a negative determination. In S323A, the power transmission control unit 110 returns to S322 when determining that the battery temperature T is lower than the temperature threshold Tzz, and proceeds to S324 when determining that the battery temperature T is equal to or higher than the temperature threshold Tzz. In S324, the power transmission control unit 110 performs CC charging at the first connection, that is, constant current charging at 20 to 30% of the rated current.

In S326 executed after S324 or S325, the power transmission control unit 110 returns to S322 when making an affirmative decision, and proceeds to S327 when making a negative decision. In S327, the power transmission control unit 110 performs CV charging for the first connection using the above-described Equation 4, and proceeds to S328. The detailed operation in S327 is as described above. In S328, the power transmission control unit 110 proceeds to S329 if an affirmative determination is made, and returns to S327 if a negative determination is made. In S329, the power transmission control unit 110 records the identification information of the power receiving apparatus 200 in association with the value of the maximum capacity Qmax calculated in S327 in the storage unit 150, and ends the process illustrated in FIG.

Note that 80%, which is the criterion in S309 and S326, is a numerical value showing an example of the high gain region, and it is desirable to set appropriately according to the characteristics of each battery 30. Further, when the power transmission control unit 110 ends the process illustrated in FIG. 6, the power reception device 200 transmits the calculated value of the maximum capacity Qmax to the power reception device 200, and causes the battery monitoring device 500 to record this.

According to the embodiment described above, the following operational effects can be obtained.
(1) The power transmission device 100 supplies power to the power reception device 200 including the battery 300. The power transmitting apparatus 100 receives the identification information from the power receiving apparatus 200, and performs the process of S301 in FIG. 6 to determine whether or not charging has been performed previously. When power transmission control unit 110 determines that charging has been performed in the past (S301: YES), power transmission device 200 performs the processes of S302 to S313. If the power transmission control unit 110 determines that charging has not been performed before (S301: NO), the power transmission control unit 110 executes the processes of S321 to S329 on the power receiving device 200. Therefore, the power transmission device 100 can perform different charging processes depending on whether charging has been performed before the power receiving device 200. In other words, the power transmission device 100 can perform appropriate charging based on the results of charging. It may be difficult to judge the individual difference between the products of the battery 300 and the problems caused by the combination with the power transmission device 100, so-called compatibility problems, unless they are connected and actually charged. Therefore, different processes can be performed by different charging processes between the power receiving apparatus 200 having a track record of charging and the power receiving apparatus 200 having no track record of charging.

(2) When the power transmission control unit 110 determines that charging has been performed in the past, the deterioration of the battery 300 and the temperature of the battery 300 are taken into consideration (S302 to S313 in FIG. 6), and charging has not been performed in the past. Is determined, the temperature of the battery 300 is taken into consideration. In the battery 300 having no record of charging, even if the deterioration state is transmitted from the power receiving device 200, there is a question that the power transmitting device 100 uses the information unconditionally and reliably. Therefore, when there is no record of charging, it is desirable to perform power transmission without considering deterioration of the battery 300 transmitted from the power receiving device 200.

(3) The amount of power transmitted in the second power transmission process is smaller than the amount of power transmitted in the first power transmission process. Therefore, the amount of power transmission can be controlled according to the performance of charging.

(4) When power transmission to the power receiving device 200 is completed, the power transmission device 100 records the identification information of the power receiving device 200 that has completed power transmission in the storage unit 150 as the power receiving device 200 that has been charged before (S313 in FIG. 6). , S329).

(5) The power transmission control unit 110 calculates the deterioration state of the battery 300 (S311, S327). The power transmission control unit 110 records the identification information of the power receiving device 200 in the storage unit 150 in association with the maximum capacity Qmax representing the battery deterioration state calculated by the power transmission control unit 110.

(Modification 1)
In the embodiment described above, the storage unit 150 is stored in the power transmission device 100. However, the storage unit 150 may be shared by a plurality of power transmission devices 100. In this case, the power transmission devices 100 that are physically adjacent to each other may be shared only with each other, or may be shared by a large number of power transmission devices 100 that are installed in different places and connected by a communication network such as the Internet. Good. The power transmission device 100 sharing the storage unit 150 may be limited to the power transmission device 100 having the same hardware configuration or software configuration, or the storage unit 150 if at least one of the hardware configuration and the software configuration is common. May be shared. Furthermore, each power transmission apparatus 100 may be individually provided with a storage unit 150, and information stored in each power transmission apparatus 100 may be transmitted to each other.

(Modification 2)
If the power transmission control unit 110 determines that the value of the maximum capacity Qmax transmitted from the power receiving device 200 is inconsistent with the maximum capacity Qmax stored in the storage unit 150, the power transmission control unit 110 may perform any of the following abnormal processes. Good. As described above, the maximum capacity Qmax takes a maximum value at the time of manufacture and decreases due to deterioration. In addition, the timing at which the maximum capacity Qmax recorded in the power transmitting apparatus 100 is calculated is estimated to be before the timing at which the maximum capacity Qmax of the power receiving apparatus 200 held by the power receiving apparatus 200 is calculated. This is because the power receiving apparatus 200 has more opportunities to update the value of the maximum capacity Qmax, and when the power transmitting apparatus 100 updates the value of the maximum capacity Qmax, the value is also transmitted to the power receiving apparatus 200. Therefore, the power receiving device 200 is updated at least at the same timing as the power transmitting device 100.

The power transmission control unit 110 performs any one of the following first to third abnormality processes. You may perform the process similar to the time of the first connection as a 1st abnormality process. This is because there is a contradiction in the value of the maximum capacity Qmax transmitted by the power receiving device 200, and the value of the reference internal resistance value R0 is not reliable. As the second abnormality process, charging may be performed using only a smaller current than that at the first connection. This is because the battery 300 may be calculated as if the maximum capacity Qmax has increased due to an abnormality. As the third abnormality process, charging may not be performed. This is to maximize safety.

(Modification 3)
In the above-described embodiment, the power transmission device 100 and the power reception device 200 perform power feeding wirelessly using an alternating magnetic field. However, the power transmission device 100 and the power reception device 200 may perform power supply by wire.

The power transmission control unit 110, the power reception control unit 210, and the drive control unit 240 may be realized by software executed by a microcomputer or the like, or by hardware such as FPGA (Field-Programmable Gate Array). May be. These may be used in combination.

In the above-described embodiment, the wireless power feeding system 1 used for wireless power feeding to a vehicle such as an electric vehicle has been described. However, the present invention is not limited to wireless power feeding to a vehicle, but is applied to a wireless power feeding system for other uses. May be.

The embodiment and various modifications described above are merely examples, and the present invention is not limited to these contents as long as the features of the invention are not impaired. Moreover, although various embodiment and the modification were demonstrated above, this invention is not limited to these content. Other embodiments conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention.

1 wireless power supply system 100 power transmission device 110 power transmission control unit 130 AC power supply 140 power conversion unit 150 storage unit 200 power reception device 210 power reception control unit 240 drive control unit 250 power conversion unit 300 battery 500 battery monitoring device Qnow current amount Qmax maximum capacity

Claims

A power transmission device for supplying power to a power receiving device having a battery,
Receiving the identification information from the power receiving device, an initial determination unit for determining whether or not charging has been performed previously;
When the first determination unit determines that the charging has been performed before, the first power transmission process is performed on the power receiving device, and when the first determination unit determines that the charging is not performed before, the power receiving device receives the second power transmission process. A power transmission device comprising: a power transmission control unit that executes power transmission processing.
The power transmission device according to claim 1,
The power transmission control unit takes into account the battery degradation and the battery temperature in the first power transmission process, and considers the battery temperature in the second power transmission process.
The power transmission device according to claim 1,
A power transmission device in which a power transmission amount transmitted in the second power transmission process is smaller than a power transmission amount transmitted in the first power transmission process.
The power transmission device according to claim 1,
A power transmission device further comprising a recording unit that records the identification information of the power receiving device that has completed power transmission as the power receiving device that has been charged before power transmission to the power receiving device is completed.
The power transmission device according to claim 4,
The power transmission control unit calculates a deterioration state of the battery,
The recording unit is a power transmission device that records the identification information of the power receiving device in association with the deterioration state of the battery calculated by the power transmission control unit.
The power transmission device according to claim 1,
When the power transmission control unit determines that the initial determination unit has previously performed charging, the power transmission control unit compares the battery deterioration information received from the power receiving device with the battery deterioration information previously recorded, and the power receiving device The power transmission device that executes a third power transmission process in which the amount of power transmitted to the power receiving device is smaller than that of the second power transmission process when the deterioration information of the battery received from the battery is less severe.