Power transmission device and charging system

Abstract

To provide a new technique for improving convenience related to charging of an electronic apparatus.SOLUTION: A power transmission device 2 includes a housing 20, a power transmission unit 21, and a communication unit 22. The housing accommodates at least one of charging devices 4, 4a, and 4b. The communication unit is disposed inside the housing and configured to be able to communicate with the charging device. The power transmission unit is disposed inside the housing and configured to be able to transmit a power radio wave M for power supply relative to the charging device. Each of the charging devices is configured to perform charging operation 46 using the power radio wave, and further configured to transmit a predetermined wireless signal. The power transmission unit is configured to transmit the power radio wave toward a direction in which the predetermined wireless signal has arrived, on condition that the communication unit has received the predetermined wireless signal inside the housing.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a power transmission device and a charging system. [Background technology]

[0002] There are known electronic devices that operate by installing disposable primary batteries or rechargeable secondary batteries, etc. However, since such electronic devices require the effort of replacing and charging the batteries, there is a demand for improved convenience.

[0003] For example, Patent Document 1 discloses an electronic key charging device that has a secondary battery that can be charged by wireless power transmission in an electronic key that remotely controls vehicle equipment, and charges the secondary battery by storing the electronic key in a noise-shielded charger. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2011-254634 Summary of the Invention [Problem to be solved by the invention]

[0005] In the prior art such as that disclosed in Patent Document 1, in order to charge an electronic device or a secondary battery, the electronic device or secondary battery must be placed in a predetermined location, and problems have been found in that multiple electronic devices or secondary batteries cannot be charged at one time.

[0006] One aspect of the present disclosure is to provide a new technology for improving convenience in charging electronic devices. [Means for solving the problem]

[0007] One aspect of the present disclosure is a power transmission device (2) including a housing (20), a communication unit (22), and a power transmission unit (21). The housing is configured to accommodate at least one charging device (4). The communication unit is disposed inside the housing and configured to be able to communicate with the at least one charging device. The power transmission unit is disposed inside the housing and configured to be able to transmit power radio waves (M), which are radio waves for supplying power, to the at least one charging device.

[0008] Each of the at least one charging device is configured to perform a charging operation using power radio waves and is further configured to transmit a predetermined wireless signal. The power transmitting unit is configured to transmit power radio waves in the direction from which the predetermined wireless signal arrived, on condition that the communication unit receives the predetermined wireless signal inside the housing.

[0009] With this configuration, the power transmission device can charge the charging device by wireless charging regardless of the location of the charging device. Therefore, the user does not need to be overly conscious of the location of the charging device when charging. Therefore, the convenience of charging the charging device can be improved. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating a configuration of a charging system. [Figure 2] FIG. 2 is a block diagram showing a configuration of a power transmission device. [Figure 3] 10 is a diagram illustrating how to replace the primary battery of the smart key with a charging device. FIG. [Figure 4] FIG. 2 is a block diagram showing the configuration of a charging device. [Figure 5] 10 is a flowchart illustrating a power transmission process of a power transmission device. [Figure 6] 10 is a flowchart showing a remaining charge notification process of the charging device. [Figure 7] 4 is a flowchart showing a power supply control process of the charging device. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, exemplary embodiments of the present disclosure will be described with reference to the drawings. [1. First embodiment] [1-1.Configuration] [1-1-1. Overall structure] 1 is a system for charging a charging device 4 using a power transmission device 2 that transmits power using radio waves. The charging device 4 is used as a battery that is attached to a smart key 3 for a vehicle, for example.

[0012] The smart key 3 is a key for a vehicle that can remotely control the vehicle. By emitting weak radio waves, the smart key 3 allows the user to unlock and lock the vehicle doors, turn the vehicle ignition switch on and off, and so on, simply by approaching the vehicle.

[0013] The charging system 1 includes a power transmission device 2 and a charging device 4. The power transmission device 2 is box-shaped and configured to be able to house the charging device 4. The power transmission device 2 is configured to be able to charge the charging device 4 arranged inside the power transmission device 2 using a wireless charging method. In the wireless charging method, charging power is supplied to the charging device 4 in the form of radio waves. The charging device 4 may be arranged alone inside the power transmission device 2, or may be arranged together with the smart key 3 while being attached to the smart key 3. The number of charging devices 4 arranged inside the power transmission device 2 may be one or more.

[0014] [1-1-2. Configuration of power transmission equipment] The power transmitting device 2 shown in FIG. 2 is configured to charge the charging device 4 disposed inside the power transmitting device 2 by a wireless charging method using radio waves for transmitting power.

[0015] The power transmitting device 2 includes a housing 20, a power transmitting unit 21, a communication unit 22, a processor 23, a memory 24, and a storage 25. The housing 20 is a box with a lid that can be opened and closed. The housing 20 is configured to be able to house various devices inside. The housing 20 is configured to prevent radio waves generated inside the housing 20 from propagating outside the housing 20 when the lid of the housing 20 is closed. For example, the housing 20 is made of a material that blocks radio waves. As an example, the housing 20 is made of metal.

[0016] The power transmitting unit 21 is disposed inside the housing 20. The power transmitting unit 21 is configured to generate and transmit microwaves M using power supplied from a power source (not shown). The microwaves M are radio waves (hereinafter referred to as power radio waves) for supplying power to the charging device 4. The power transmitting unit 21 transmits the directional microwaves M via the power transmitting antenna 211. The frequency band of the microwaves M is, for example, the 2.4 GHz band. Hereinafter, transmitting the power radio waves (for example, the microwaves M) from the power transmitting unit 21 will be referred to as power transmission.

[0017] The power transmitting unit 21 is configured to be able to transmit microwaves M in any direction through a power transmitting antenna 211. The power transmitting antenna 211 is configured by, for example, an array antenna. The microwaves M are output from the power transmitting antenna 211 as directional radio waves.

[0018] The power transmitting unit 21 may be configured to transmit directional electric power radio waves other than microwaves M. Examples of directional radio waves include UHF (Ultra High Frequency) and millimeter waves. The frequency bands of these radio waves are, for example, the 920 MHz band and the 5.7 GHz band.

[0019] The communication unit 22 is disposed inside the housing 20. The communication unit 22 is configured to be able to communicate with electronic devices disposed inside and outside the housing 20 by wireless communication via an internal antenna 221 and an external antenna 222.

[0020] The communication unit 22 is configured to be able to communicate individually with a plurality of electronic devices arranged inside the housing 20 via the internal antenna 221. The communication between the communication unit 22 and the electronic devices may be wireless communication, for example, by LF (Low Frequency), RF (Radical Frequency), Bluetooth (registered trademark), microwaves, etc.

[0021] The communication unit 22 is configured to be able to detect the direction from which the radio waves used to transmit a wireless communication signal (hereinafter simply referred to as a wireless signal) arrive when the communication unit 22 receives the wireless communication signal via the internal antenna 221. The internal antenna 221 is configured by, for example, an array antenna.

[0022] 1, the communication unit 22 is configured to be able to communicate with a communication terminal 5 outside the housing 20 (i.e., outside the power transmitting device 2) via an external antenna 222. Examples of the communication terminal 5 include a smartphone, a tablet terminal, and a personal computer.

[0023] As will be described later, the communication terminal 5 can acquire the remaining battery power of the charging device 4 through the communication unit 22. The communication terminal 5 can update computer programs held by the power transmission device 2, the charging device 4, etc. by transmitting software update information for the charging system 1 through the communication unit 22.

[0024] The processor 23 is configured to execute processing in accordance with a computer program recorded in the storage 25 . The memory 24 is used as a work area when the processor 23 executes processing. Examples of the memory 24 include a random access memory (RAM), a read only memory (ROM), and a flash memory.

[0025] The storage 25 holds computer programs. Examples of the storage 25 include an embedded multi-media card (eMMC) and a universal flash storage (UFS).

[0026] [1-1-3. Configuration of charging device] The smart key 3 shown in FIG. 3 operates by receiving a supply of operating power from a primary battery 32 attached to an attachment portion 31 or from a charging device 4.

[0027] 3, when the primary battery 32 is removed from the mounting portion 31 of the smart key 3, the charging device 4 is mounted in the mounting portion 31 as a replacement battery for the primary battery 32. When mounted in the mounting portion 31, the charging device 4 is configured to supply the smart key 3 with the operating power required for the smart key 3 to operate.

[0028] The charging device 4 has an outer shape compatible with the primary battery 32. In this embodiment, the primary battery 32 is a coin battery. The charging device 4 has a coin shape compatible with the primary battery 32. As shown in FIG. 4, the charging device 4 includes a communication interface 41, a secondary battery 42, a CPU 43, a RAM 44, a ROM 45, a charging circuit 46, a remaining capacity measuring circuit 47, and a power supply circuit 48.

[0029] The communication interface 41 is an interface capable of transmitting and receiving various signals in accordance with a predetermined wireless communication standard. The charging device 4 is configured to be able to communicate with both the power transmitting unit 21 and the communication unit 22 of the power transmitting device 2 through the communication interface 41. The communication interface 41 has a data communication antenna 411 and a power receiving antenna 412.

[0030] The data communication antenna 411 is configured to enable data communication with the communication unit 22 of the power transmitting device 2. Communication with the communication unit 22 may be wireless communication, for example, using LF (Low Frequency), RF (Radical Frequency), Bluetooth (registered trademark), microwaves, or the like.

[0031] The power receiving antenna 412 is configured to be able to receive the power radio wave (that is, the microwave M) transmitted from the power transmitting unit 21 of the power transmitting device 2. When data communication with the communication unit 22 of the power transmitting device 2 is performed using microwaves M, one antenna may be shared as the data communication antenna 411 and the power receiving antenna 412.

[0032] The secondary battery 42 is configured to be rechargeable by the charging circuit 46. The secondary battery 42 is configured to supply operating power to the smart key 3 to which the charging device 4 is attached, for operating the smart key 3. The power supplied from the secondary battery 42 is also used to operate the charging device 4.

[0033] The remaining battery capacity of the secondary battery 42 is measured by the remaining battery capacity measurement circuit 47. The remaining battery capacity is the ratio of the supplyable operating power amount divided by the operating voltage to the maximum capacity of the battery. For example, if the maximum capacity of the secondary battery 42 is 200 mAh, the operating voltage is 3 V, and the supplyable operating power amount is 300 mWh, the remaining battery capacity is (300 mWh ÷ 3 V) ÷ 200 mAh = 50%. Hereinafter, the remaining battery capacity of the secondary battery 42 is also referred to as the remaining battery capacity of the charging device 4.

[0034] The remaining battery charge and the amount of operating power that can be supplied by the secondary battery 42 increase when the secondary battery 42 is charged by the charging circuit 46, and decrease when power is supplied to the smart key 3. The remaining battery charge and the amount of operating power that can be supplied by the secondary battery 42 also decrease due to various processes performed by the charging device 4, standby power of the charging device 4, etc.

[0035] The CPU 43 is configured to execute processes in accordance with a computer program stored in the ROM 45. CPU is an abbreviation for Central Processing Unit.

[0036] The RAM 44 is used as a working area when the CPU 43 executes processing. RAM is an abbreviation for Random Access Memory. Examples of the RAM 44 include SRAM (Static Random Access Memory) and DRAM (Dynamic Random Access Memory).

[0037] The ROM 45 stores computer programs. ROM stands for Read Only Memory. Examples of the ROM 45 include flash memory and EEPROM (Electrically Erasable and Programmable Read Only Memory).

[0038] The charging circuit 46 is configured to receive the power radio waves (i.e., microwaves M) transmitted by the power transmitting device 2 via the power receiving antenna 412, and to perform a charging operation of charging the secondary battery 42 using the received power radio waves. The charging circuit 46 includes a rectifier circuit (not shown), and is configured to convert an AC signal corresponding to the power radio waves received by the power receiving antenna 412 into a DC current by the rectifier circuit, thereby charging the secondary battery 42.

[0039] The remaining battery capacity measuring circuit 47 is configured to be able to measure the remaining battery capacity of the secondary battery 42. Examples of methods for measuring the remaining battery capacity include a voltage measurement method, a current measurement method, and an impedance tracking method.

[0040] The power supply circuit 48 is configured to supply the operating power required for the smart key 3 to operate from the secondary battery 42 to the smart key 3 when the charging device 4 is attached to the attachment portion 31 of the smart key 3. The supply of operating power by the power supply circuit 48 is performed through a power supply terminal 481 in contact with the attachment portion 31 of the smart key 3.

[0041] The charging device 4 has a power supply prohibited state and a power supply permitted state as states related to the supply of operating power. In the power supply prohibited state, the charging device 4 is configured not to supply operating power from the power supply circuit 48. In the power supply permitted state, the charging device 4 is configured to allow the power supply circuit 48 to supply operating power.

[0042] [1-2. Processing] [1-2-1. Power transmission processing] The power transmission process to the charging device 4 (in other words, the charging process of the charging device 4) executed by the processor 23 of the power transmission device 2 will be described with reference to the flowchart of FIG.

[0043] With the cover of the housing 20 closed, the processor 23 executes the power transmission process shown in FIG. 5 at predetermined time intervals (for example, every 10 seconds). First, in S100, the processor 23 transmits a request signal to the entire interior of the housing 20 via the communication unit 22. The request signal requests transmission of the remaining battery capacity of the secondary battery 42 included in the charging device 4.

[0044] Thereafter, processor 23 determines whether or not a remaining battery level signal has been received in response to the request signal through communication unit 22. The remaining battery level signal indicates the remaining battery level of secondary battery 42 in charging device 4. The remaining battery level signal is transmitted from charging device 4 that has received the request signal. In other words, processor 23 determines whether or not the remaining battery level of secondary battery 42 has been acquired.

[0045] If the processor 23 determines in S100 that the remaining battery charge signal has not been received (S100: NO), it considers that the remaining battery charge has not been acquired, and ends the power transmission process in FIG. On the other hand, if the processor 23 determines in S100 that a remaining amount signal has been received (S100: YES), the processor 23 determines that the remaining battery amount has been acquired, and proceeds to S105. In S105, the processor 23 determines whether or not one remaining amount signal has been received.

[0046] If the processor 23 determines in S105 that one remaining amount signal has been received (S105: YES), it proceeds to S110 and transmits microwaves M as power radio waves from the power transmission unit 21 in the direction from which the remaining amount signal arrived.

[0047] The secondary battery 42 of the charging device 4 that receives the microwaves M is charged by the charging circuit 46. The processor 23 continues transmitting power in the direction from which the remaining battery level signal came until the remaining battery level indicated by the remaining battery level signal exceeds a predetermined remaining battery level threshold. The processor 23 transmits a request signal requesting a remaining battery level signal via the communication unit 22 and receives the remaining battery level signal in response to the request signal, thereby checking the remaining battery level of the secondary battery 42 at any time. The processor 23 stops transmitting power when the remaining battery level indicated by the remaining battery level signal exceeds a predetermined remaining battery level threshold. Thereafter, the processor 23 ends the power transmission process of FIG. 5. The predetermined remaining battery level threshold is, for example, any percentage between 80% and 90% of the maximum capacity of the secondary battery 42.

[0048] On the other hand, if the processor 23 determines in S105 that more than one remaining charge signal has been received, i.e., that multiple remaining charge signals have been received (S105: NO), the processor 23 proceeds to S115 and determines the secondary battery 42 with the relatively lowest remaining charge among the remaining battery charges of the multiple secondary batteries 42 indicated by the multiple remaining charge signals. Hereinafter, the secondary battery 42 with the relatively lowest remaining charge will be referred to as the low remaining battery. If there are multiple secondary batteries 42 with the relatively lowest remaining charge, the processor 23 may determine one of them as the low remaining battery.

[0049] To explain the processing at S115, consider a case in which a first charging device 4a including a first secondary battery 42a and a second charging device 4b including a second secondary battery 42b are arranged within the housing 20 as charging devices 4 each including a secondary battery 42. In this case, in response to a request signal from the power transmitting device 2, the first charging device 4a including the first secondary battery 42a and the second charging device 4b including the second secondary battery 42b each transmit a remaining amount signal. The processor 23 receives two remaining amount signals as the plurality of remaining amount signals: a first remaining amount signal indicating the remaining amount of the first secondary battery 42a and a second remaining amount signal indicating the remaining amount of the second secondary battery 42b. Hereinafter, the remaining amount of the first secondary battery 42a indicated by the first remaining amount signal will be referred to as the first remaining amount. The remaining amount of the second secondary battery 42b indicated by the second remaining amount signal will be referred to as the second remaining amount.

[0050] In S115, the processor 23 determines whether the first secondary battery 42a or the second secondary battery 42b has a low remaining battery capacity by comparing the magnitude relationship between the first remaining battery capacity and the second remaining battery capacity.

[0051] If the processor 23 determines in S115 that the first battery remaining amount is less than the second battery remaining amount (S115: first battery remaining amount<second battery remaining amount), it determines that the first secondary battery 42a is a low-battery remaining amount, and proceeds to S120.

[0052] In S120, processor 23 transmits power in the direction from which the first remaining charge signal came. Processor 23 continues transmitting power in the direction from which the first remaining charge signal came until the first remaining charge of first secondary battery 42a, which is a low remaining charge battery, exceeds at least a predetermined remaining charge threshold. The predetermined remaining charge threshold is the same as in S110.

[0053] Next, in S125, processor 23 transmits power in the direction from which the second remaining battery level signal arrived. Processor 23 continues transmitting power in the direction from which the second remaining battery level signal arrived until the second remaining battery level of second secondary battery 42b exceeds at least a predetermined remaining battery level threshold. The predetermined remaining battery level threshold is the same as in S110.

[0054] After that, the processor 23 ends the power transmission process of FIG. On the other hand, if the processor 23 determines in S115 that the first battery remaining capacity is equal to or greater than the second battery remaining capacity (S115: first battery remaining capacity ≧ second battery remaining capacity), it determines that the second secondary battery 42b is a low battery and proceeds to S130.

[0055] In S130, processor 23 transmits power in the direction from which the second remaining charge signal came. Processor 23 continues transmitting power in the direction from which the second remaining charge signal came until the second remaining charge of second secondary battery 42b, which is a low remaining charge battery, exceeds at least a predetermined remaining charge threshold. The predetermined remaining charge threshold is the same as in S110.

[0056] Next, in S135, processor 23 transmits power in the direction from which the first remaining battery level signal arrived. Processor 23 continues transmitting power in the direction from which the first remaining battery level signal arrived until the first remaining battery level of first secondary battery 42a exceeds at least a predetermined remaining battery level threshold. The predetermined remaining battery level threshold is the same as in S110.

[0057] After that, the processor 23 ends the power transmission process of FIG. In this way, the power transmitting device 2 is configured to transmit the microwaves M in the direction from which the remaining amount signal has arrived, on condition that the communication unit 22 has received the remaining amount signal.

[0058] When the communication unit 22 receives a plurality of remaining amount signals, the power transmitting device 2 is configured to determine the secondary battery 42 whose remaining battery amount indicated by the remaining amount signal is the relatively smallest as the low remaining battery, and to transmit microwaves M in the direction from which the remaining amount signal indicating the remaining battery amount of the low remaining battery has arrived. The power transmitting device 2 is configured to transmit microwaves M in the direction from which the remaining amount signal has arrived in order of decreasing remaining battery amount.

[0059] [1-2-2. Remaining Amount Notification Processing] The remaining amount notification process executed by the CPU 43 of the charging device 4 will be described with reference to the flowchart of FIG.

[0060] When the CPU 43 receives the request signal transmitted by the power transmitting device 2 in S100 via the communication interface 41, it executes the remaining amount notification process shown in FIG. First, in S200, the CPU 43 acquires the remaining battery capacity of the secondary battery 42 through the remaining capacity measuring circuit 47.

[0061] Next, in S205, the CPU 43 transmits a remaining amount signal indicating the acquired remaining battery amount to the power transmitting device 2 via the communication interface 41. Thereafter, the CPU 43 ends the remaining amount notification process of FIG.

[0062] In this way, the charging device 4 is configured to transmit a remaining battery level signal indicating the remaining battery level of the secondary battery 42 to the power transmitting device 2 on the condition that a request signal has been received from the power transmitting device 2. Through this process, the charging device 4 notifies the power transmitting device 2 of the remaining battery level of the secondary battery 42.

[0063] [1-2-3. Power supply control processing] The power supply control process for the smart key 3 executed by the CPU 43 of the charging device 4 will be described with reference to the flowchart in Fig. 7. The power supply control process switches the charging device 4 between a power supply prohibited state and a power supply permitted state in accordance with radio waves received by the charging device 4.

[0064] When the communication interface 41 receives a radio wave, the CPU 43 starts the power supply control process shown in FIG. First, in S300, the CPU 43 determines whether the radio wave intensity of the received radio wave is equal to or greater than a predetermined intensity threshold. The intensity threshold is, for example, 30 dBm. In this embodiment, the microwave M has a radio wave intensity that exceeds the predetermined intensity threshold.

[0065] If the CPU 43 determines in S300 that the radio wave intensity is equal to or greater than the threshold value (S300: YES), the CPU 43 proceeds to S315 and transitions to a power supply prohibited state. After that, the CPU 43 ends the power supply control process of FIG.

[0066] On the other hand, if the CPU 43 determines in S300 that the radio wave intensity of the received radio waves is less than the predetermined intensity threshold (S300: NO), the CPU 43 proceeds to S305 and determines whether the frequency of the received radio waves is a frequency for charging. The frequency for charging is, for example, a frequency included in a frequency band such as the 920 MHz band, the 2.4 GHz band, or the 5.7 GHz band. In this embodiment, the frequency of the microwaves M is included in the frequency band for charging.

[0067] If the CPU 43 determines in S305 that the frequency of the received radio wave is the frequency for charging (S305: YES), the CPU 43 proceeds to S315 and transitions to a power supply prohibited state. After that, the CPU 43 ends the power supply control process of FIG.

[0068] On the other hand, if the CPU 43 determines in S305 that the frequency of the received radio wave is not the frequency for charging (S305: NO), the CPU 43 proceeds to S310 and transitions to the power supply permitted state. After that, the CPU 43 ends the power supply control process of FIG.

[0069] In this way, the charging device 4 transitions to a power supply prohibited state when the radio wave intensity of the radio wave received by the communication interface 41 is equal to or greater than a predetermined intensity threshold, or when the frequency of the received radio wave is a frequency for charging. In this case, the charging device 4 determines that the secondary battery 42 is being charged, and does not supply operating power to the smart key 3. In other words, the smart key 3 does not operate.

[0070] On the other hand, if the radio wave intensity of the radio wave received by the communication interface 41 is below a predetermined intensity threshold and the frequency of the received radio wave is not a charging frequency, the charging device 4 transitions to a power supply permitted state. In this case, the charging device 4 can supply operating power to the smart key 3. In other words, the smart key 3 is operable.

[0071] [1-2-4. Charging system processing] 1, the charging process of the charging device 4 using the power transmission device 2 is performed with the charging device 4 disposed inside the housing 20 of the power transmission device 2. The charging device 4 disposed inside the housing 20 may be disposed alone, or may be disposed together with the smart key 3 while being attached to the smart key 3. Multiple charging devices 4 may be disposed inside the housing 20 at the same time.

[0072] When the lid of the housing 20 is closed with the charging device 4 placed inside the housing 20, the power transmitting device 2 starts the power transmitting process to the charging device 4 at predetermined time intervals as shown in the flowchart of Fig. 5. The subsequent process is as described above.

[0073] [1-3.Effects] According to the embodiment described above in detail, the following effects can be obtained. (1a) When the processor 23 of the power transmitting device 2 receives a remaining amount signal via the communication unit 22, the processor 23 is configured to transmit microwaves M from the power transmitting unit 21 in the direction from which the remaining amount signal arrived. The remaining amount signal is transmitted from the charging device 4. The secondary battery 42 of the charging device 4 that receives the microwaves M is charged by the charging circuit 46.

[0074] According to this configuration, the power transmission device 2 can charge the charging device 4 by wireless charging regardless of the location of the charging device 4. Therefore, the user does not need to be overly conscious of the location of the charging device 4 when charging the charging device 4. This improves the convenience of charging the charging device 4.

[0075] (1b) The charging process of the charging device 4 using the power transmission device 2 is performed with the charging device 4 placed inside the housing 20 of the power transmission device 2. The charging device 4 placed inside the housing 20 may be placed alone, or may be placed together with the smart key 3 while being attached to the smart key 3.

[0076] According to this embodiment, the secondary battery 42 of the charging device 4 can be charged without removing the charging device 4 from the smart key 3. This improves the convenience of charging the charging device 4.

[0077] (1c) When multiple charging devices 4 are placed inside the housing 20 at the same time, the power transmission device 2 transmits microwaves M in the direction from which the remaining battery charge signal arrived, in order of decreasing battery charge level, until the remaining battery charge of each battery exceeds a predetermined remaining battery charge threshold.

[0078] According to this configuration, when multiple charging devices 4 are placed inside the housing 20, the multiple charging devices 4 are charged in sequence. After a sufficient amount of time has passed, the remaining battery power of each of the multiple charging devices 4 exceeds a predetermined remaining power threshold. In other words, even if multiple charging devices 4 are placed inside the housing 20 at the same time, after a sufficient amount of time has passed, the remaining battery power of each of the multiple charging devices 4 will be charged until it exceeds a predetermined remaining power threshold. This improves the convenience of charging multiple charging devices 4.

[0079] (1d) The microwaves M used for charging have directionality. Therefore, the charging system 1 of this embodiment can achieve more efficient charging than when transmitting power radio waves that have no directionality (in other words, transmitting power radio waves in all directions).

[0080] (1e) The charging device 4 has an external shape compatible with the primary battery 32 attached to the smart key 3. When the primary battery 32 is removed from the attachment portion 31 of the smart key 3, the charging device 4 is attached to the attachment portion 31 and used as a battery in place of the primary battery 32.

[0081] With this configuration, the smart key 3 can be easily wirelessly charged by replacing the primary battery 32 with the charging device 4, without modifying or replacing the smart key 3. This reduces the effort required to periodically replace the disposable primary battery 32.

[0082] Furthermore, the charging device 4 attached to the smart key 3 can be replaced with the primary battery 32. Therefore, the user can easily switch between using the primary battery 32 or the charging device 4 to operate the smart key 3 according to how the user uses it.

[0083] (1f) The power transmitting device 2 continues transmitting power in the direction from which the remaining battery level signal arrived until the remaining battery level indicated by the remaining battery level signal exceeds at least a predetermined remaining battery level threshold. When the remaining battery level indicated by the remaining battery level signal exceeds the predetermined remaining battery level threshold, the power transmitting device 2 stops transmitting power.

[0084] This configuration prevents the secondary battery 42 from being charged until the remaining battery capacity reaches 100%, thereby preventing the secondary battery 42 from being consumed due to overcharging. (1g) When the communication interface 41 receives radio waves and the radio wave intensity of the received radio waves is equal to or greater than a predetermined intensity threshold, the charging device 4 transitions to a power supply prohibited state.

[0085] Additionally, when the communication interface 41 receives radio waves and the frequency of the received radio waves is a frequency for charging, the charging device 4 transitions to a power supply prohibited state. With this configuration, when the secondary battery 42 is being charged, the smart key 3 does not emit weak radio waves to operate various vehicle functions. This prevents unauthorized attacks such as relay attacks on a smart key 3 equipped with a charging secondary battery 42. A relay attack is a theft method used to gain unauthorized access to a vehicle by amplifying and relaying weak radio waves emitted by a smart key 3 placed, for example, at the entrance of a home.

[0086] Furthermore, when the secondary battery 42 is being charged, the charging device 4 does not supply power to the smart key 3, so the secondary battery 42 can be charged faster than when power is supplied to the smart key 3.

[0087] (1h) The power transmission process to the charging device 4 executed by the power transmission device 2 is executed in a state where the lid of the housing 20 is closed. The housing 20 is configured to suppress propagation of radio waves generated inside the housing 20 to the outside of the housing 20 in a state where the lid of the housing 20 is closed.

[0088] With this configuration, while the charging device 4 is being charged by the power transmitting device 2, radio waves generated inside the housing 20 are prevented from propagating outside the housing 20. In other words, while the smart key 3 equipped with the charging device 4 is placed inside the housing 20 and the charging device 4 is being charged, weak radio waves emitted from the smart key 3 are prevented from propagating outside the housing 20. This makes it possible to prevent the smart key 3 from being subjected to unauthorized attacks such as relay attacks.

[0089] Furthermore, while the power transmitting device 2 is charging the charging device 4, microwaves M are transmitted inside the housing 20. At this time, the cover of the housing 20 is closed, so that the microwaves M, which are radio waves with high radio field intensity and high frequency, are prevented from propagating outside the housing 20. This allows safe wireless charging.

[0090] (1i) In the power transmitting device 2, the external antenna 222 is disposed outside the housing 20. The communication unit 22 is configured to be able to communicate with a communication terminal 5 outside the housing 20 (that is, outside the power transmitting device 2) via the external antenna 222.

[0091] With this configuration, even when the lid of the housing 20 is closed, i.e., when the charging device 4 is being charged, the communication unit 22 can transmit the remaining battery power of the charging device 4 to the communication terminal 5 via the external antenna 222, and can obtain software update information for the charging system 1 from the communication terminal 5.

[0092] That is, the user can obtain the remaining battery level of the charging device 4 and transmit software update information for the charging system 1 via the communication terminal 5 while leaving the charging device 4 inside the housing 20. This improves convenience.

[0093] [1-4. Correspondence between terms] In the above embodiment, the process of charging the secondary battery 42 using power radio waves received via the communication interface 41 corresponds to an example of a charging operation, and the remaining battery level signal corresponds to an example of a predetermined wireless signal. The process of S115 corresponds to an example of a determination process, the charging frequency corresponds to an example of a predetermined frequency, and the smart key 3 corresponds to an example of an electronic device. The transmission of the remaining battery level signal realized by the process of S205 executed by the communication interface 41 and the CPU 43 corresponds to an example of transmitting a remaining battery level signal by a communication circuit.

[0094] 2. Other Embodiments Although the embodiments of the present disclosure have been described above, it goes without saying that the present disclosure is not limited to the above-described embodiments and can take on various forms.

[0095] (2a) The number of charging devices 4 placed inside the housing 20 for charging is not limited to one or two, but may be three or more. Each of the multiple charging devices 4 may or may not be attached to the smart key 3 when placed inside the housing 20 for charging.

[0096] (2b) The device to which the charging device 4 is attached as a battery is not limited to the smart key 3. (2c) The primary battery 32 and the charging device 4 are not limited to being coin-shaped. The charging device 4 may have any shape that is compatible with the primary battery 32. For example, the primary battery 32 and the charging device 4 may be cylindrical, prismatic, button-shaped, etc.

[0097] (2d) In the above embodiment, the power transmission device 2 charges the multiple charging devices 4 in ascending order of the remaining battery power. That is, the power transmission device 2 transmits power to the multiple charging devices 4 in ascending order of the remaining battery power. This power transmission is referred to as sequential power transmission here.

[0098] However, the power transmitting device 2 may be configured to simultaneously transmit microwaves M in multiple directions from which multiple remaining amount signals arrive. That is, the power transmitting device 2 may simultaneously transmit power to multiple charging devices 4. This type of power transmission is referred to as parallel power transmission here.

[0099] The power transmitting device 2 may perform a combination of sequential power transmission and parallel power transmission to a plurality of charging devices 4. For example, the power transmitting device 2 may continue transmitting power in the direction from which the first remaining battery level signal arrived until the first remaining battery level indicated by the first remaining battery level signal exceeds the first remaining battery level threshold. After the first remaining battery level indicated by the first remaining battery level signal exceeds the first remaining battery level threshold, the power transmitting device 2 may continue transmitting power in both the direction from which the first remaining battery level signal arrived and the direction from which the second remaining battery level signal arrived until the first remaining battery level exceeds the second remaining battery level threshold. After the first remaining battery level exceeds the second remaining battery level threshold, the power transmitting device 2 may not transmit power in the direction from which the first remaining battery level signal arrived.

[0100] The power transmitting device 2 may change the radio wave intensity depending on the direction in which the microwaves M are transmitted. For example, the power transmitting device 2 may transmit power such that the radio wave intensity of the microwaves M transmitted in the direction from which the second remaining amount signal arrives is greater than the radio wave intensity of the microwaves M transmitted in the direction from which the first remaining amount signal arrives. According to this process, the charging speed of the multiple charging devices 4 can be changed for each charging device 4.

[0101] (2e) The charging operation of the charging circuit 46 is not limited to charging the secondary battery 42 provided in the charging device 4, and may be configured to charge a secondary battery externally attached to the charging device 4. An example of a secondary battery externally attached to the charging device 4 is a mobile battery.

[0102] (2f) Multiple functions possessed by one component in the above embodiments may be realized by multiple components, or one function possessed by one component may be realized by multiple components. Also, multiple functions possessed by multiple components may be realized by one component, or one function realized by multiple components may be realized by one component. Also, part of the configuration of the above embodiments may be omitted. Also, at least part of the configuration of the above embodiments may be added to or substituted for the configuration of another of the above embodiments.

[0103] (2g) The present disclosure may be realized in various forms in addition to the above-described power transmission device, charging device, and charging system. For example, the present disclosure may be realized in the form of a system including the power transmission device, charging device, or charging system as a component, a computer program for causing a computer to function as the power transmission device, charging device, or charging system, a non-transitory tangible recording medium such as a semiconductor memory on which the computer program is recorded, a charging method, etc. [Explanation of symbols]

[0104] 1...charging system, 2...power transmission device, 4, 4a, 4b...charging device, 20...casing, 21...power transmission unit, 22...communication unit, 23...processor, 46...charging circuit, 211...power transmission antenna, 221...internal antenna, M...microwave.

Claims

1. A power transmission device (2), a housing (20) for housing at least one charging device (4); a communication unit (22) disposed inside the housing and configured to be able to communicate with the at least one charging device; a power transmission unit (21) arranged inside the housing and configured to be able to transmit a power radio wave (M) that is a radio wave for supplying power to the at least one charging device; Equipped with each of the at least one charging device is configured to perform a charging operation using the power radio waves and further configured to transmit a predetermined wireless signal; the power transmission unit is configured to transmit the power radio wave in a direction from which the predetermined wireless signal has arrived, on condition that the communication unit has received the predetermined wireless signal inside the housing. Power transmission equipment.

2. The power transmitting device according to claim 1 , The housing is configured to suppress propagation of radio waves generated inside the housing to the outside of the housing. Power transmission equipment.

3. The power transmitting device according to claim 1 , The power radio wave transmitted by the power transmission unit has directionality. Power transmission equipment.

4. The power transmitting device according to claim 3, the at least one charging device includes a first charging device (4a) equipped with a first secondary battery (42a) and a second charging device (4b) equipped with a second secondary battery (42b); the first charging device is configured to transmit, as the predetermined wireless signal, a first remaining amount signal indicating a remaining amount of the first secondary battery; the second charging device is configured to transmit, as the predetermined wireless signal, a second remaining amount signal indicating a remaining amount of the second secondary battery; the power transmitting unit is configured to transmit the power radio wave in at least one of a direction from which the first remaining amount signal has arrived and a direction from which the second remaining amount signal has arrived, based on a remaining battery amount of the first secondary battery indicated by the first remaining amount signal and a remaining battery amount of the second secondary battery indicated by the second remaining amount signal. Power transmission equipment.

5. The power transmitting device according to claim 4, The power transmission unit is executes a determination process to determine, based on the first remaining battery level signal and the second remaining battery level signal received by the communication unit, which of the first secondary battery and the second secondary battery has a relatively low remaining battery level as a low remaining battery; the power radio wave is transmitted in a direction from which the predetermined wireless signal arrived from one of the first charging device and the second charging device, the charging device having the low remaining battery; Power transmission equipment.

6. The power transmitting device according to claim 5, the power transmission unit is configured to, after executing the determination process, continue to transmit the power radio wave in a direction from which the predetermined wireless signal from the charging device having the low battery arrived, until the remaining battery charge of the low battery exceeds at least a predetermined remaining charge threshold. Power transmission equipment.

7. A charging system (1) including the power transmission device according to any one of claims 3 to 6, further comprising the at least one charging device; Each of the at least one charging device A secondary battery (42); a charging circuit (46) configured to receive the power radio wave from the power transmitting device and charge the secondary battery using the received power radio wave as the charging operation; a communication circuit (41, 43, S205) configured to transmit a remaining amount signal indicating a remaining battery amount of the secondary battery to the power transmitting device as the predetermined wireless signal; a power supply circuit (49) configured to be able to supply, when attached to an electronic device (3), operating power required for the electronic device to operate from the secondary battery to the electronic device; A charging system comprising:

8. 8. The charging system according to claim 7, the at least one charging device is configured not to supply the operating power to the electronic device when the charging circuit is charging the secondary battery using the power radio waves. Charging system.

9. 8. The charging system according to claim 7, The power radio wave transmitted by the power transmission unit has a predetermined frequency, the at least one charging device is configured not to supply the operating power to the electronic device when receiving radio waves of the predetermined frequency. Charging system.

10. 8. The charging system according to claim 7, the at least one charging device is configured not to supply the operating power to the electronic device when receiving radio waves having a radio wave intensity equal to or greater than a predetermined intensity threshold. Charging system.

11. 8. The charging system according to claim 7, the electronic device is configured to be operable by a primary battery, the at least one charging device has an outer shape compatible with the primary battery; Charging system.

12. 8. The charging system according to claim 7, The electronic device is a smart key for a vehicle. Charging system.

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