Charge / discharge device, charge / discharge system and charge / discharge method

Abstract

To efficiently perform charging.SOLUTION: A charge / discharge device 100 which charges a secondary battery 60 and a capacitor 70 with power generated by natural energy comprises: a high current power source section 21 which charges the secondary battery 60 with generated power of a current equal to or more than a minimum charging current value specific for the secondary battery 60; a low current power source section 22 which charges the capacitor 70 with generated power using a current less than the minimum charging current value; and a discharge switch SW2 which connects any one of the secondary battery 60 and the capacitor 70 to a power source unit 110. Maximum output voltages of the high current power source section 21 and the low current power source section 22 are approximately equal to the maximum power source voltage of the power source unit 110.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a charge / discharge device, a charge / discharge system, and a charge / discharge method. [Background technology]

[0002] 2. Description of the Related Art Natural energy such as solar power generation or wind power generation is used to collect sensor information such as temperature and vibration, and the sensor information is wirelessly transmitted to a remote location (see Patent Document 1). In the charge / discharge device described in Patent Document 1, the power generated by solar power generation is charged to a secondary battery or a capacitor. Specifically, a large current exceeding a minimum charging current specific to the secondary battery is charged to the secondary battery, and a small current equal to or smaller than the minimum charging current is charged to the capacitor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6786999 (Claim 1) Summary of the Invention [Problem to be solved by the invention]

[0004] Natural energy power generation can be applied not only to solar power generation and wind power generation, but also to thermal power generation that utilizes the temperature difference in pipes. The power generated by thermal power generation is generally much less than that of solar power generation and wind power generation. Therefore, the power efficiency of the charger and switch that charge the capacitor with a small current becomes an issue.

[0005] The present invention has been made to solve such problems, and has an object to provide a charge / discharge device, a charge / discharge system, and a charge / discharge method that enable charging with high power efficiency. [Means for solving the problem]

[0006] In order to achieve the above object, the present invention is a charging / discharging device that charges a first secondary battery (secondary battery 60) and one or both of a capacitor (70) and a second secondary battery (secondary battery 61) different from the first secondary battery with received power, and is characterized by comprising a large current charger (high current power supply unit 21) that charges the first secondary battery with a current equal to or greater than a set value (e.g., a first minimum charging current value specific to the first secondary battery), and a small current charger (low current power supply unit 22) that charges the received power to the power storage device with a current less than the set value. Note that the symbols and letters in parentheses are symbols and the like that are added in the embodiment and do not limit the present invention. Effect of the Invention

[0007] According to the present invention, charging can be achieved with high power efficiency. [Brief description of the drawings]

[0008] [Figure 1] 1 is a configuration diagram of a charge / discharge system according to a first embodiment of the present invention. [Diagram 2] 4 is a flowchart for explaining the operation of the charging / discharging device of the present invention. [Diagram 3] FIG. 4 is a configuration diagram of a charge / discharge system according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Note that each drawing is merely a schematic view to allow a sufficient understanding of the embodiment. In addition, in each drawing, common or similar components are given the same reference numerals, and duplicated explanations thereof will be omitted.

[0010] (First embodiment) FIG. 1 is a configuration diagram of a charge / discharge system according to a first embodiment of the present invention. The charge / discharge system 1000 includes a natural energy power generation device 10, a charge / discharge device 100, and a wireless sensor device 200.

[0011] The natural energy power generation device 10 includes a solar power generation device, a wind power generation device, a water current power generation device, a thermal power generation device, and the like. A solar power generation device is a solar panel, and a wind power generation device is a generator connected to a windmill or a propeller. A water current power generation device is suitable for generating power in, for example, a culvert. A thermal power generation device generates power from the temperature difference between the ambient temperature (outside air temperature) and a pipe through which hot water flows, for example, in a boiler room. Such a thermal power generation device can operate 24 hours a day, but generates less power than a solar power generation device or a wind power generation device.

[0012] The charging / discharging device 100 is composed of two switches SW1, SW2, a high current power supply unit 21 as a large current charger, a low current power supply unit 22 as a low current charger, current monitor units 31, 32, a voltage monitor unit 40, a control unit 50, a secondary battery 60 as a first secondary battery, a capacitor 70 as a power storage device, and a primary battery 75. The switch SW1 is a two-contact switch, with a terminal c connected to the natural energy power generation device 10, a terminal a connected to the high current power supply unit 21, and a terminal b connected to the low current power supply unit 22. As a result, the switch SW1 functions as an input switch that receives power generated by the natural energy power generation device 10 and supplies the received power to either the high current power supply unit 21 or the low current power supply unit 22.

[0013] The high current power supply unit 21 is a constant current charging circuit that charges the secondary battery 60 using the power generated by the natural energy power generation device 10. The low current power supply unit 22 is a constant current charging circuit that charges the capacitor 70 using the power generated by the natural energy power generation device 10. The high current power supply unit 21 and the low current power supply unit 22 have a maximum power point tracking (HPPT) function that maintains the natural energy power generation device 10 at a voltage that generates power most efficiently. In the case of a thermal power generation device, the generated power is generally low, so the charging current that charges the capacitor 70 and the secondary battery 60 or other power storage devices is also low.

[0014] The secondary battery 60 is, for example, a lithium ion battery, a nickel metal hydride battery, a nickel-cadmium battery, or a lead storage battery. The secondary battery 60 has a characteristic that charging is not performed with a small current, and charging is started at a minimum charging current value or more specific to the secondary battery. In other words, the secondary battery 60 is charged only when a charging current I B The secondary battery 60 is charged at a charging current of 3100 mAh. The first minimum charging current value [A] specific to the secondary battery 60 is predetermined depending on the type, structure, etc., and is, for example, 0.01 to 0.02 times the capacity [Ah] of the secondary battery 60. Specifically, when the capacity of the secondary battery 60 is, for example, 3100 [mAh], the first minimum charging current value is 31 [mA] to 62 [mA].

[0015] In other words, the high current power supply unit 21 generates a charging current I B In addition, the low current power supply unit 22 can supply a charging current I that is less than or equal to a first minimum charging current value specific to the secondary battery 60. C can flow. Also, the maximum output voltage of high current power supply unit 21 (maximum charging voltage of secondary battery 60) and the maximum output voltage of low current power supply unit 22 (maximum charging voltage of capacitor 70) are assumed to be approximately equal to the maximum power supply voltage value of power supply unit 110. Therefore, low current power supply unit 22 has less power loss than high current power supply unit 21. Incidentally, in a step-up type power supply unit or a transformer type power supply unit that uses a coil, an excitation current flows, so that if the load current is the same, low current power supply unit 22 has less power loss than high current power supply unit 21.

[0016] The capacitor 70 is, for example, an electric double layer capacitor or a lithium ion capacitor. Unlike the secondary battery 60, the capacitor 70 can be charged with even a minute current.

[0017] The switch SW2 is a three-contact switch with its terminal a connected to the positive electrode of the secondary battery 60, its terminal b connected to the positive electrode of the capacitor 70, its terminal c open (OFF), and its terminal d connected to the power supply unit 110 of the wireless sensor 200. In this way, the switch SW2 functions as a discharge switch that discharges either the charge stored in the secondary battery 60 or the charge stored in the capacitor 70 to the power supply unit 110 of the wireless sensor 200. When the switch SW2 is connected to the open terminal c, the power supply unit 110 is driven by the charging voltage stored in the primary battery 75.

[0018] The current monitor unit 31 monitors the charging current I B The current monitor 32 monitors the charging current I C The voltage monitor unit 40 monitors the charging voltage V B and the charging voltage V of the capacitor 70 C Monitor the following:

[0019] The control unit 50 is a CPU (Central Processing Unit) and executes a control program to control the switches SW1 and SW2 in accordance with the monitoring results (measured values) of the current monitors 31 and 32 and the voltage monitor 40. That is, the control unit 50 controls the switch SW1 to adjust the charging current I B is equal to or greater than a set value (for example, a minimum charging current value specific to the secondary battery 60), the generated power (received power) is supplied to the high current power supply unit 21, and the charging current I B is less than the set value, the control unit 50 supplies the generated power to the low current power supply unit 22. The control unit 50 also controls the wireless unit 12 of the wireless sensor 200.

[0020] The wireless sensor 200 comprises a primary battery 75, a power supply unit 110 as a load, a sensor device 120, and a wireless device 130. The power supply unit 110 supplies a charging voltage V B ,V CThe power supply unit 110 is driven by the charging voltage of the primary battery 75. The primary battery 75 is disposed in front of the power supply unit 110, and when the switch SW2 is connected to the c terminal (open), the power supply unit 110 is driven by the charging voltage of the primary battery 75. The maximum current consumption of the power supply unit 110 is about 1 A, but the average current consumption is several mA. This average current consumption (several mA) is less than the charging current of the capacitor 70 due to thermal power generation. The power supply voltage of the power supply unit 110 and the charging voltage of the capacitor 70 are similar. In other words, the power generated by thermal power generation is equal to or greater than the average load power of the power supply unit 110, which is the load.

[0021] The sensor device 120 is a sensor that detects temperature, vibration, etc. The wireless device 130 transmits sensor information detected by the sensor device 120 to the wireless devices 130 and base stations of other charging and discharging systems. As a result, the sensor information is transmitted by multi-hop communication via multiple charging and discharging systems.

[0022] FIG. 2 is a flow chart for explaining the operation of the charge / discharge device of the present invention. This flow is always activated after the switch SW1 is set to contact a or contact b when the power is turned on or after a reset. The control unit 50 (FIG. 1) detects the charging current I B ,I C In other words, when the secondary battery 60 is being charged, the control unit 50 determines whether the charging current I detected by the current monitor unit 31 exceeds the minimum charging current value of the secondary battery 60 (S1). B On the other hand, when the capacitor 70 is being charged, the control unit 50 determines whether the charging current I detected by the current monitor unit 32 exceeds the minimum charging current value. C It is determined whether or not the minimum charging current value is exceeded.

[0023] The charging current I monitored by the current monitor units 31 and 32 B ,I CWhen the charging current I exceeds the first minimum charging current value specific to the secondary battery 60 (S1: over minimum charging current value), the control unit 50 sets the switch SW1 to contact a and performs high current charging of the secondary battery 60 (S2). B ,I C When the charging current is equal to or less than the first minimum charging current value specific to the secondary battery 60 (equal to or less than the minimum charging current value at S1), the control unit 50 switches the switch SW1 to contact b and performs low current charging on the capacitor 70 (S3).

[0024] After the process of S3, the control unit 50 controls the charging voltage V C It is determined whether the charging voltage V of the capacitor 70 exceeds a threshold value (S4). C When the charging current I exceeds the threshold (exceeds the threshold in S4), the control unit 50 switches the switch SW2 to terminal b, and discharges the capacitor 70 to the power supply unit 110 (S5). After the process of S5, the control unit 50 returns the process to S1, and the charging current I B ,I C A determination is made.

[0025] Charging voltage of capacitor 70 V C When the charging voltage V of the secondary battery 60 is equal to or less than the threshold (below the threshold in S4) or after the process of S2, the control unit 50 B It is determined whether the charging voltage V of the secondary battery 60 exceeds the threshold value (S6). B When the charging voltage V of the secondary battery 60 exceeds the threshold (S6: over threshold), the control unit 50 switches the switch SW2 to terminal a, and discharges the charge from the secondary battery 60 to the power supply unit 110 (S5). B When the charging current I is equal to or less than the threshold (equal to or less than the threshold in S6), the control unit 50 turns the switch SW2 OFF (terminal c) (S8). This causes the power supply unit 110 to be driven by the charging voltage of the electrolytic capacitor 75. After the process of S8, the control unit 50 returns the process to S1 and the charging current I B ,I C A determination is made.

[0026] As described above, according to the charging / discharging device 100 of this embodiment, the power generated by the natural energy power generation device 10 is stored in the secondary battery 60 or the capacitor 70. At this time, the charging current I B ,I C If the charging current V is less than the first minimum charging current value specific to the secondary battery 60, the low current power supply unit 22 charges the capacitor 70. B and the charging voltage of capacitor 70 V C Therefore, by having low current power supply unit 22 charge capacitor 70 as a power storage device, power efficiency is improved compared to when high current power supply unit 21 alone charges capacitor 70 with a charging current that is less than the first minimum charging current value specific to secondary battery 60.

[0027] Second embodiment In the first embodiment, the secondary battery 60 and the capacitor 70 (FIG. 1) are used, but two secondary batteries 60, 61 (FIG. 3) having different capacities may also be used.

[0028] FIG. 3 is a configuration diagram of a charge / discharge system according to a second embodiment of the present invention. The charging / discharging system 1001, like the charging / discharging system 1000 (FIG. 1) of the first embodiment, is configured to include a natural energy power generation device 10 and a wireless sensor device 200. The charging / discharging system 1001 differs from the charging / discharging device 100 of the first embodiment in that a charging / discharging device 101 is provided instead of the charging / discharging device 100 (FIG. 1).

[0029] Similar to the charging / discharging device 100 of the first embodiment, the charging / discharging device 101 includes two switches SW1, SW2, a high current power supply unit 21, a low current power supply unit 22, current monitor units 31, 32, a control unit 50, a secondary battery 60 serving as a first secondary battery, and a primary battery 75. However, the charging / discharging device 101 differs from the charging / discharging device 100 of the first embodiment in that the charging / discharging device 101 is provided with a secondary battery 61 serving as an electricity storage device and a second secondary battery, instead of the capacitor 70 (FIG. 1).

[0030] The secondary battery 61 has a smaller capacity than the secondary battery 60 and a smaller minimum charging current value (second minimum charging current value) than the secondary battery 60. Therefore, the low current power supply unit 22 supplies a charging current I C The low current power supply unit 22 charges the secondary battery 61, thereby improving power efficiency compared to the high current power supply unit 21 independently charging the secondary battery 61 as a power storage device with a charging current that is less than the first minimum charging current value specific to the secondary battery 60 and more than the second minimum charging current value specific to the secondary battery 61. The secondary battery 61 discharges to the power supply unit 110 as a load with an average current that is less than the second minimum charging current value.

[0031] (Modification) The present invention is not limited to the above-described embodiment, and various modifications are possible, for example, as follows. (1) In the first embodiment, the low current power supply unit 22 charges the capacitor 70, and in the second embodiment, the low current power supply unit 22 charges the secondary battery 61. In this regard, the low current power supply unit 22 may charge the secondary battery 61 and the capacitor 70. In other words, the power storage device charged by the low current power supply unit 22 is either or both of the first secondary battery (secondary battery 60) and the capacitor 70 (FIG. 3) and the second secondary battery (secondary battery 61 (FIG. 3)).

[0032] (2) In the above embodiments, only the sensor device 120 and the wireless device 130 were connected to the power supply unit 110, but a camera or lighting device (not shown) can also be connected. Even if only the sensor device 120 and the wireless device 130 are connected to the power supply unit 110 and the power generated by thermal power generation exceeds the average power consumption of the power supply unit, etc., solar power generation or wind power generation is required when a camera, lighting device, etc. is connected. [Explanation of symbols]

[0033] 10. Natural energy power generation equipment 21 High current power supply section (high current charger) 22 Low current power supply section (low current charger) 31, 32 Current monitor section 40 Voltage monitor section 50 Control section 60 Secondary battery (1st secondary battery) 61 Secondary battery (secondary battery, power storage device) 70 Capacitor (electricity storage device) 100,101 Charging and discharging equipment 110 Power supply section (load) 200 Wireless sensor device 1000,1001 Charging and discharging system SW1 switch (input switch) SW2 switch (discharge switch)

Claims

1. A charging / discharging device that charges a first secondary battery and one or both of a capacitor and a second secondary battery different from the first secondary battery with received power, a large current charger that charges the first secondary battery with the received power at a current equal to or greater than a set value; a small current charger that charges the power storage device with the received power at a current less than the set value; A charging / discharging device comprising:

2. The set value is a first minimum charging current value specific to the first secondary battery.

2. The charging / discharging device according to claim 1 .

3. The power storage device is a capacitor.

3. The charging / discharging device according to claim 1 or 2.

4. the power storage device is the second secondary battery having a smaller capacity than the first secondary battery, The small current charger charges the second secondary battery with a current equal to or greater than a second minimum charging current value specific to the second secondary battery.

3. The charging / discharging device according to claim 2.

5. a discharge switch that connects one or both of the first secondary battery and the power storage device to a load; The received power is equal to or greater than an average load power of the load, The second secondary battery is discharged to the load at an average current less than the second minimum charging current value.

5. The charging / discharging device according to claim 4.

6. a discharge switch that connects one or both of the first secondary battery and the power storage device to a load; The maximum output voltage of the large current charger and the small current charger is approximately equal to the maximum power supply voltage of the load.

2. The charging / discharging device according to claim 1 .

7. A charging / discharging device that charges a first secondary battery and one or both of a capacitor and a second secondary battery with received power, a large current charger that charges the first secondary battery with the received power; a small current charger that charges the power storage device with the received power; an input switch for supplying the received power to either the large current charger or the small current charger; a control unit that controls the input switch to supply the received power to the large current charger when a charging current for charging the first secondary battery is equal to or greater than a set value, and to supply the received power to the small current charger when a charging current for charging the first secondary battery is less than a set value; A charging / discharging device comprising:

8. A charge / discharge system including a natural energy power generation device, a charge / discharge device that charges one or both of a first secondary battery, a capacitor, and a second secondary battery different from the first secondary battery with power generated by the natural energy power generation device, and a load that discharges the charge stored in the power storage device, the charging / discharging device is a large current charger that charges the first secondary battery with the generated power at a current equal to or greater than a set value; a small current charger that charges the generated power to the power storage device with a current less than the set value; a discharge switch that connects either the first secondary battery or the power storage device to the load, The maximum output voltage of the large current charger and the small current charger is approximately equal to the maximum power supply voltage of the load. A charging and discharging system comprising:

9. A charging / discharging method executed by a charging / discharging device that charges a first secondary battery and one or both of a capacitor and a second secondary battery with received power, the method comprising: the charging / discharging device includes a large current charger that charges the first secondary battery, and a small current charger that charges the power storage device with the received power, When a charging current for charging the first secondary battery is equal to or greater than a set value, the received power is supplied to the large current charger, and when a charging current for charging the first secondary battery is less than a set value, the received power is supplied to the small current charger. A charging and discharging method comprising the steps of:

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