JP2015012751A - Power storage device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage device which can be quickly charged while securing an energy density in an available size.SOLUTION: A power storage device is configured by combining a secondary battery 10 and a capacitor 20. When charging the secondary battery 10 and the capacitor 20, charging is performed in the order of the capacitor → the secondary battery and when discharging them (also when outputting power), discharging is performed in the order of the capacitor → the secondary battery. Under such charging/discharging control, quick charging can be performed while securing an energy density in an available size (device capacity). Further, since the capacitor 20 can be used preferentially, the number of times of charging/discharging the secondary battery 20 can be reduced. Thus, an apparent cycle lifetime as an entire power storage device can be prolonged in comparison with the case where the secondary battery is used singly.

Description

  The present invention relates to a power storage device that can be charged and discharged.

  Secondary batteries are used as power sources for electric bicycles such as electric assist bicycles, electric wheelchairs, electric golf carts, and electric tools, and lithium ion batteries are particularly used (for example, Patent Documents 1 to 3). 3). Secondary batteries such as lithium ion batteries are also used as power sources for devices and devices such as mobile phones and personal computers, and vehicles such as electric vehicles (EV) and hybrid vehicles (HV).

JP2011-244555A JP 2011-034793 A JP2011-079510A JP 2010-187471 A

  By the way, in order to charge a lithium ion battery safely, it is usually necessary to charge with a charging current of about 0.2 times the rated capacity and at most about 1 time of the rated capacity. For this reason, a lithium ion battery of about 250 Wh requires, for example, about 2 to 4 hours to be fully charged, and has a drawback that the charging time is long. Note that if a quick charger is used for charging the lithium ion battery, the charging time can be shortened to some extent. However, if the quick charging is performed, the battery is rapidly deteriorated due to heat generation during charging.

  In addition, as a lithium ion battery, as the depth of discharge increases, deterioration during charging / discharging (cycle deterioration) increases and the cycle life becomes shorter, and deterioration proceeds faster when stored while maintaining a fully charged state. There is a point to do.

  On the other hand, there is a capacitor as a power source used for equipment and devices. Compared with the secondary battery, the capacitor has an advantage that the output density is high and the internal resistance is low, so that quick charging with a large current is possible and the cycle life is much longer. For example, the number of times of charging (allowable number of times) of the secondary battery is about 1000 times, while the number of times of charging the capacitor is 100,000 times or more. However, the capacitor has a lower energy density (Wh / kg) than that of the lithium ion battery (for example, the energy density of the capacitor is about several tenths that of the lithium ion battery). For this reason, when a power storage device is constructed using only a capacitor, it is necessary to significantly increase the capacity of the capacitor (device volume) in order to ensure the same energy as that of the lithium ion battery.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a power storage device that can be rapidly charged while ensuring energy density with a practical size.

  The present invention is a power storage device that can be charged and discharged, and includes a secondary battery, a capacitor, and a controller that controls charging and discharging of the secondary battery and the capacitor. The control unit controls charging in the order of charging of the capacitor and charging of the secondary battery when charging the power to the power storage device, and when discharging power from the power storage device, A technical feature is that the discharge is controlled in the order of discharge of the capacitor and discharge of the secondary battery.

  According to the power storage device of the present invention, a secondary battery (for example, a lithium ion battery) and a capacitor (for example, a lithium ion capacitor) are combined, and when charging, [capacitor] → [secondary battery] Since charging is performed in order, rapid charging can be performed on a part (capacitor) of the entire capacity of the power storage device. Accordingly, even when the capacity of the power storage device is exhausted (battery is exhausted), the use of a load (for example, an electric motor of an electric bicycle) can be performed in a short time by rapid charging. In addition, when performing normal charging (charging the entire power storage device over time), it is possible to perform charging control by charging the capacitor first and then slowly charging the secondary battery. Therefore, deterioration due to rapid charging of the secondary battery can be prevented.

  Furthermore, when discharging the power storage device (output to the load), the discharge is controlled in the order of [capacitor] → [secondary battery]. For example, until the remaining capacity of the capacitor is exhausted, Charge control of performing quick charge (charging at no load) is possible. Thereby, it becomes possible to reduce the frequency | count of discharge of a secondary battery, and can reduce the burden of a secondary battery.

  As described above, according to the power storage device of the present invention, the secondary battery and the capacitor are combined, and charging / discharging of the secondary battery and the capacitor is controlled in the order of [capacitor] → [secondary battery]. Therefore, it is possible to perform rapid charging while ensuring energy density with a practical size (device volume). In addition, since the capacitor can be used preferentially, the number of times the secondary battery is charged and discharged can be reduced. As a result, the apparent cycle life of the entire power storage device can be extended as compared with the case of using a secondary battery alone.

  In the power storage device of the present invention, when the power storage device is charged with power, when a capacitor to be charged first becomes fully charged, a notification unit (for example, lamp lighting or You may provide the alerting | reporting part which alert | reports by a sound. By adopting such a configuration, it is possible to notify the user that the rapid charging has been completed for part of the entire capacity of the power storage device (the full charging of the capacitor has been completed) by lighting the lamp or sound. Therefore, the user can visually and audibly confirm that the load can be used.

  In the power storage device of the present invention, when the capacity of the capacitor is exhausted, power is discharged (outputs power) from the secondary battery. Then, when the capacitor is fully charged during discharging of the secondary battery, control may be performed to switch the power discharge (power output) from the secondary battery to the capacitor. If such a configuration is adopted, the power of the secondary battery will be discharged (power is output) after the capacity of the capacitor is used up, but the charging speed of the capacitor is fast, so Since the discharge time is very short, the burden on the secondary battery can be reduced.

  In the power storage device of the present invention, the charge capacity of the secondary battery may be controlled to be kept below a predetermined set upper limit value (charge control upper limit line) lower than the fully charged state of the secondary battery. In this way, maintaining the secondary battery in a low charge state (SOC (State Of Charge) ≦ set upper limit value) can delay the deterioration of the secondary battery.

  As a specific configuration of the power storage device of the present invention, the power storage device can be connected to at least one of a renewable energy power generation device and a minute energy recovery device, and at least one of the renewable energy power generation device and the minute energy recovery device. The capacitor can be charged using the power from

  Examples of the renewable energy power generation device include a solar power generation device, a hydroelectric power generation device, and a wind power generation device. The minute energy recovery device is a device that generates electric power (energy harvesting) by utilizing minute energy existing around us such as radio waves, room light, vibration, heat (temperature difference).

  In addition, by using the power from the renewable energy power generation device and the minute energy recovery device in this way, the capacitor can be charged even when there is no power supply power source (for example, an AC power source) nearby. . Since the capacitor has a low internal resistance, it can be charged even with a weak amount of power generated by sunlight in cloudy weather or a small amount of power recovered by a micro energy recovery device.

  Here, in the power storage device of the present invention, as described above, rapid charging is possible. For example, when a battery runs out, such as an electric bicycle, an electric wheelchair, and an electric golf cart, it is desired to perform quick charging. The present invention can be effectively used for electric devices and apparatuses that need to prepare a plurality of charged batteries such as vehicles and electric tools. The power storage device of the present invention can also be used as a power source for electronic devices such as mobile phones and personal computers, and vehicles such as electric vehicles (EV) and hybrid vehicles (HV).

  According to the power storage device of the present invention, the secondary battery and the capacitor are combined, and charging and discharging of the secondary battery and the capacitor are performed in the order of [capacitor] → [secondary battery]. Thus, rapid charging can be performed while ensuring energy density. In addition, since the capacitor can be used preferentially, the number of times the secondary battery is charged and discharged can be reduced. As a result, the apparent cycle life of the entire power storage device can be extended as compared with the case of using a secondary battery alone.

It is a block diagram which shows schematic structure of the electrical storage apparatus of this invention. It is a figure which shows the structure of the display part provided in the electrical storage apparatus. It is a figure which shows the example of a display of a display part. It is a flowchart which shows an example of charge control of an electrical storage apparatus. It is a flowchart which shows an example of the discharge control of an electrical storage apparatus. It is a timing chart which shows an example of the discharge control of an electrical storage apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  An example of the power storage device of the present invention will be described with reference to FIG.

  The power storage device 1 of this example includes a secondary battery 10, a capacitor 20, a control unit 30, a display unit 40, and the like. In this example, a lithium ion battery is used for the secondary battery 10, and a lithium ion capacitor is used for the capacitor 20. In this example, the ratio of the volume ratio between the secondary battery 10 (lithium ion battery) and the capacitor 20 (lithium ion capacitor) is 7: 3. The secondary battery 10 may be another secondary battery such as a nickel metal hydride battery. Also, the capacitor 20 may be another capacitor such as an electric double layer capacitor (capacitor).

  SOC detectors 34 and 35 for detecting SOC (%) are connected to the secondary battery 10 and the capacitor 20, respectively. The SOC detection unit 34 detects, for example, the charge / discharge current of the secondary battery 10 by a current sensor or the like, and detects (calculates) the SOC from the integrated value of the charge / discharge current. Similarly, the SOC detection unit 35 detects (calculates) the SOC based on the integrated value of the charge / discharge current of the capacitor 20. The detected values of the SOC detection units 34 and 35 are respectively input to an input control unit 31, an output control unit 32, and a [capacitor → secondary battery] charge control unit 33 which will be described later. In the present invention, the SOC may be referred to as “capacity” or “charge capacity”.

-Control unit-
The control unit 30 controls the charging from the input control unit 31, the output control unit 32, and the capacitor 20 to the secondary battery 10 [capacitor → secondary battery] charge control unit 33 (hereinafter referred to as a secondary battery charge control unit 33). ), And the SOC detectors 34 and 35 described above.

−Input control unit−
The input control unit 31 includes an AC / DC converter 311, a DC / DC converter 312, a protection circuit (not shown) that prevents overcharge of the secondary battery 10, and the like. The input control unit 31 is provided with an AC input connector (for example, socket) 313 and a DC input connector (for example, socket) 314. The AC input connector 313 can be connected to an AC power source (commercial power source: AC 100 V) 201 via a plug, a cable (not shown), and the like. The DC input connector 314 can be connected to one or both of the renewable energy power generation apparatus 202 and the minute energy recovery apparatus 203 via a plug and a cable (not shown).

  Here, when the AC power supply 201 is connected to or disconnected from the AC input connector 313, the input control unit 31 is connected to or disconnected from the DC input connector 314 by the renewable energy power generation device 202 or the minute energy recovery device 203. In this case, it is configured so that connection / disconnection of the power supply can be recognized.

  Examples of the renewable energy power generation device 202 include a solar power generation device, a hydroelectric power generation device, and a wind power generation device. Examples of the minute energy recovery device 203 include an element that converts light into electricity (such as a small dye-sensitized solar cell), an element that converts radio waves into electricity (such as a rectenna that converts microwaves into direct current), Using elements that convert mechanical operations such as vibration into electricity (piezoelectric elements, electromagnetic induction elements, electret elements, etc.), and elements that convert heat with temperature differences into electricity (Seebeck elements, Peltier elements), etc. An energy recovery device can be mentioned.

  The input control unit 31 converts the AC power from the AC power supply 201 into DC power by the AC / DC converter 311 in a charged state where the AC power supply 201 is connected to the AC input connector 313, and converts the DC power to the capacitor. 20 to charge the capacitor 20. Charging of the capacitor 20 by the input control unit 31 is controlled based on the detection value of the SOC detection unit 34 (capacitance of the capacitor 20). Details of the charge control will be described later.

  The input control unit 31 directly outputs the power from the AC power source 201 (DC power converted by the AC / DC converter 311) to the secondary battery 10 based on the detection value of the SOC detection unit 34, and The secondary battery 10 may be charged.

  In addition, when either or both of the renewable energy power generation device 202 and the minute energy recovery device 203 are connected to the DC input connector 314, the input control unit 31 converts the generated / recovered DC power into a DC / DC converter. At 312, the voltage is transformed (transformed into a charging voltage) and output to the capacitor 20 to charge the capacitor 20.

-Secondary battery charge controller-
The secondary battery charge control unit 33 outputs the power of the capacitor 20 to the secondary battery 10 when the capacity of the secondary battery 10 is less than a set upper limit CL described later in the no-load state. The battery 10 is charged. The charging of the secondary battery 10 by the secondary battery charging control unit 33 is based on the detection value of the SOC detection unit 34 when the capacity of the secondary battery 10 reaches the set upper limit value CL (SOC = setting upper limit value). CL).

  Here, as described above, a secondary battery such as a lithium ion battery has a drawback that deterioration proceeds quickly (calendar life is shortened) when stored while maintaining a fully charged state. In consideration of such points, in this embodiment, a capacity value lower than full charge (SOC = 100%) is set as a set upper limit value CL (charge control upper limit line) (%), and the secondary battery 10 By maintaining the capacity (%) not exceeding the set upper limit value CL (charging and discharging the secondary battery 10 at a shallow depth of discharge), the deterioration of the secondary battery 10 is delayed. Here, 50% can be cited as an example of the set upper limit value CL. The set upper limit value CL is not limited to “50%”, and other values (capacity [%]) may be set as appropriate.

  In the present embodiment, when the power storage device 1 is charged with power, charging is performed in the order of [capacitor 20] → [secondary battery 10]. Details of the charge control will be described later.

−Output control unit−
The output control unit 32 includes a DC / DC converter 321 and a constant voltage output circuit (not shown). The output control unit 32 is provided with a DC output connector 322, and the load 101 is connected to the DC output connector 322. Examples of the load 101 include an electric motor of an electric bicycle.

  The output control unit 32 transforms the power charged in the capacitor 20 or the secondary battery 10 by the DC / DC converter 321 (transforms the operating voltage of the load 101) and outputs (discharges) the power to the load 101. The power output (discharge) by the output control unit 32 is controlled based on detection values of the SOC detection units 34 and 35 (capacity (%) of the secondary battery 10 and capacity (%) of the capacitor 20). In this embodiment, when power is output to the load 101, power output (discharge) is performed in the order of [capacitor 20] → [secondary battery 10]. Details of output control of power to the load 101 will be described later.

  A display unit (notification unit) 40 that displays the state of charge of the power storage device 1 is connected to the control unit 30 described above. As shown in FIGS. 2 and 3, the display unit 40 includes a charging lamp 41 that indicates that the power storage device 1 is being charged, a quick charge end lamp 42 that indicates that quick charging has ended, and the power storage device 1. And the entire charging end lamp 43 indicating that charging of both the capacitor 20 and the secondary battery 10 has been completed. The lighting (see FIG. 3) of the lamps 41, 42, 43 of the display unit 40 is controlled by the input control unit 31 of the control unit 30. The lighting control will be described later. Note that LED lamps, EL lamps, and the like are used for the lamps 41, 42, and 43.

-Charge control-
Next, an example of charge control during no load will be described with reference to the flowchart of FIG. The processing routine of FIG. 4 is executed by the control unit 30.

  The processing routine of FIG. 4 is started when the AC power supply 201 is connected to the AC input connector 313 of the power storage device 1. In the case where the power storage device 1 is provided with a charge switch, the processing routine of FIG. 4 is started when the charge switch is turned on.

  When the processing routine of FIG. 4 is started, first, the charging lamp 41 of the display unit 40 is turned on (see FIG. 3A). In step ST101, the capacitor 20 is turned on based on the detection value of the SOC detection unit 35. It is determined whether or not the battery is fully charged (SOC = 100%).

  If the determination result in step ST101 is negative (NO), the process proceeds to step ST102 and the capacitor 20 is charged. The capacitor charging process in step ST102 is repeatedly performed until the capacitor 20 is fully charged. When the capacitor 20 is fully charged, the determination result in step ST101 is affirmative (YES), and the process proceeds to step ST103.

  In step ST103, it is determined whether or not to continue charging. This process will be described. First, after the start of charging, when step ST101 is first determined affirmative (YES), the quick charge end lamp 42 of the display unit 40 is turned on (see FIG. 3B), and the load 101 is informed that the use of 101 is possible (for example, an electric bicycle can be run), and the capacitor 20 is in a standby state for a certain time (for example, several minutes) from the time when the capacitor 20 is fully charged. If the user performs a charge termination operation (for example, disconnecting the power storage device 1 from the AC power supply 201 or turning off the charge switch), the charge is terminated (determination result in step ST103 is negative (NO)). . At the end of charging, the capacitor 20 is in a fully charged state, and the load 101 can be used (for example, an electric bicycle can be driven). The quick charge end lamp 42 is turned off when the standby time has elapsed.

  On the other hand, when the charging end operation is not performed during the standby time and when the second and subsequent determinations in step ST101 are affirmative (YES), it is determined that charging is continued and the process proceeds to step ST104.

  In step ST104, it is determined whether the capacity (%) of the secondary battery 10 is less than the set upper limit value CL (for example, CL = 50%) based on the detection value of the SOC detection unit 34.

  When the determination result in step ST104 is affirmative (YES) (when the capacity of the secondary battery 10 <the set upper limit CL), the process proceeds to step ST105. In step ST105, the charging power of the capacitor 20 is output to the secondary battery 10 to charge the secondary battery 10 (charging from the capacitor 20 to the secondary battery 10).

  Next, in step ST106, it is determined whether or not the capacitor 20 has a capacity based on the detection value of the SOC detection unit 35. When the determination result in step ST106 is affirmative (YES) (when the capacitor 20 has a capacity (SOC> 0)), the charging of the secondary battery 10 from the capacitor 20 is continued (step ST105).

  When the determination result in step ST106 is negative (NO) (when the capacitor 20 has no capacity (SOC = 0)), the process returns to step ST102. At this time, since the capacitor 20 is not fully charged, the capacitor 20 is charged. The capacitor charging process in step ST102 is repeatedly performed until the capacitor 20 is fully charged.

  When the capacitor 20 is fully charged, the determination result in step ST101 is affirmative (YES). Since the capacitor 20 is fully charged at this time, the determination result in step ST103 is affirmative (charge continuation determination), and the process proceeds to step ST104. In step ST104, it is determined whether or not the capacity (%) of the secondary battery 10 is less than the set upper limit CL (for example, CL = 50%). If the determination result is affirmative (YES). Proceed to step ST105. Thereafter, until the processing of steps ST105 to ST106 and steps ST101 to ST102 (charging from the capacitor 20 to the secondary battery 10 and charging of the capacitor 20) reaches the set upper limit CL. When the capacity of the secondary battery 10 reaches the set upper limit CL (when the determination result of step ST104 is negative determination (NO)), the entire charge end lamp 43 of the display unit 40 is turned on. It lights up (refer FIG.3 (c)), and charge is complete | finished.

  In the above charging control, when charging the secondary battery 10, the power of the capacitor 20 is output to the secondary battery 10 to perform charging. The secondary battery 10 may be charged by directly outputting electric power (DC power converted by the AC / DC converter 311) to the secondary battery 10.

-Output control to load-
Next, output control (discharge control) of power to the load will be described with reference to the flowchart of FIG. The processing routine of FIG. 5 is executed by the control unit 30.

  The processing routine of FIG. 5 is started, for example, when a load-side power switch is turned on. When this processing routine is started, first, in step ST201, it is determined whether or not the capacitor 20 has a capacity based on the detection value of the SOC detection unit 35. If the determination result is affirmative (YES) (when [SOC> 0]), power is output (discharged) from the capacitor 20 to the load 101 (step ST202). The power output from the capacitor 20 continues until the capacity of the capacitor 20 runs out (SOC = 0). When the capacity of the capacitor 20 runs out, the determination result in step ST201 is negative (NO), and the process proceeds to step ST203.

  In step ST203, it is determined whether the secondary battery 10 has capacity. When the determination result is affirmative (YES) (when [SOC> 0]), power is output (discharged) from the secondary battery 10 to the load 101 (step ST204).

  Next, in step ST205, it is determined whether or not charging from an external power source (AC power source 201, renewable energy power generation device 202, or minute energy recovery device 203) is possible. If the determination result is affirmative (YES), the process proceeds to step ST206 and the capacitor 20 is charged (the capacitor 20 is charged while the secondary battery 10 is being discharged). The capacitor charging process in step ST206 is repeated until the capacitor 20 is fully charged. Then, when the capacitor 20 is fully charged, the determination result of step ST207 is affirmative (YES), and at this time, power output (discharge) from the secondary battery 10 is stopped (step ST208). Thereafter, the process returns to step ST201, and the above-described processes of steps ST201 to ST208 (charging / discharging of the capacitor 20 and partial discharging of the secondary battery 10) are sequentially repeated.

  On the other hand, if the determination result in step ST205 is negative (NO), that is, if charging from an external power source is impossible, the process returns to step ST203 to determine whether the secondary battery 10 has capacity. judge. When the determination result is affirmative (YES) (when [SOC> 0]), power is output from the secondary battery 10 to the load 101 (step ST204). The power output from the secondary battery 10 is continuously performed until the capacity of the secondary battery 10 is exhausted (until the determination result in step ST203 is negative (NO)). Then, when the capacity of the secondary battery 10 is exhausted, the power output to the load 101 is terminated.

  Next, power output control (discharge control) to the load 101 will be specifically described with reference to the timing chart of FIG.

  First, the capacity of the secondary battery 10 is charged to the set upper limit value CL, and the capacitor 20 is fully charged. From this state, power is first output from the capacitor 20 (processing of step ST202 in FIG. 5). From the time T1 when the power output from the capacitor 20 is started, the capacity of the capacitor 20 decreases, and at the time T2 when the capacity of the capacitor 20 becomes 0 (SOC = 0), the power output is the secondary battery 10. (Steps ST203 to ST204 in FIG. 5). When charging from the external power supply is possible during the power output from the secondary battery 10, charging of the capacitor 20 is started at the timing of T3 (processing of step ST206 in FIG. 5). Next, at time T4 when the capacitor 20 is fully charged, power output from the secondary battery 10 is stopped, and power is output from the capacitor 20 (processing of step ST208 and steps ST201 to ST202 in FIG. 5). Then, at the time T5 when the capacity of the capacitor 20 becomes 0 (the time when step ST201 in FIG. 5 is negative), the power output is switched to the secondary battery 10 (step ST204 in FIG. 5). Thereafter, the power output is terminated when the capacity of the secondary battery 10 becomes 0 (SOC = 0) (when the determination result of step ST203 in FIG. 5 is negative determination (NO)).

  Here, in order to simplify the explanation, the timing chart of FIG. 6 shows an example in which the capacitor 20 is charged only once, but in reality, the capacitor 20 is charged and discharged many times. It is done repeatedly. In the timing chart of FIG. 6, in order to make the explanation easy to understand, the period from the time when the power output is switched to the secondary battery 10 to the start of charging the capacitor 20 (the period from T2 to T3) is lengthened. However, in practice, charging of the capacitor 20 is started immediately after switching to the secondary battery 10. For this reason, the capacity | capacitance reduction of the secondary battery 10 only needs to be small. In this way, the number of times of charging / discharging of the secondary battery 10 can be reduced by using the capacitor 20 preferentially.

<Effect>
As described above, according to the present embodiment, the secondary battery 10 and the capacitor 20 are combined, and charging is performed in the order of [capacitor 20] → [secondary battery 10]. Therefore, it is possible to perform rapid charging for a part of the entire capacity of the power storage device 1 (capacitor 20). As a result, even when the power storage device 1 is out of capacity (battery is exhausted), the load 101 can be used (for example, running an electric bicycle) in a short time (for example, several tens of seconds: see an example described later) by rapid charging. become. In addition, when the quick charge is completed (the full charge of the capacitor 20 is completed), the user can be notified of this by turning on the quick charge lamp 42, so that the user can use the load 101. It can be confirmed visually.

  Furthermore, in the present embodiment, when power is output to the load 101 (discharge of the power storage device 1), power output (discharge) is performed in the order of [capacitor] → [secondary battery]. Can be used preferentially. This makes it possible to reduce the number of times that the secondary battery 10 is charged and discharged, and to increase the apparent cycle life of the entire power storage device as compared to the case where the secondary battery is used alone.

  Further, since the capacity of the secondary battery 10 is maintained at a predetermined set upper limit value (charge control upper limit line) CL lower than the fully charged state of the secondary battery 10, the deterioration of the secondary battery is delayed. be able to.

  Further, in the present embodiment, at least one of the renewable energy power generation device 202 and the minute energy recovery device 203 can be connected to the power storage device 1, and electric power from at least one of the renewable energy power generation device 202 and the minute energy recovery device 203. Since the capacitor 20 is charged using the power, the capacitor 20 can be charged even when there is no power supply power source (for example, the AC power source 201). Since the capacitor 20 has a low internal resistance, the capacitor 20 can be charged even with a weak power generation amount due to sunlight in cloudy weather or a small amount of power recovered by the micro energy recovery device 203.

-Example-
Next, an example in which the power storage device 1 of the present embodiment is applied to a power source of an electric bicycle will be described.

  First, a lithium ion battery is used for a power source of an electric bicycle. The specifications of the power supply unit are, for example, a charging voltage of 25 V, a charge amount of 10 Ah, an overall capacity (volume) of the power storage unit of 2 L, and a volume energy density of the power supply unit of 125 Wh / L (250 Wh).

  In this embodiment, a lithium ion battery is used as the secondary battery 10 of the power storage device 1 and a lithium ion capacitor is used as the capacitor 20. The volume ratio between the lithium ion battery and the lithium ion capacitor is 7: 3.

  Here, the volume energy density of the lithium ion capacitor is set to 20 Wh / L, the total capacity of the power storage device 1 is set to 2 L (same as the volume of the power supply unit), 1.4 L of the lithium ion battery is set to 0.6 L, and 0.6 L is set to When distributed to the lithium ion capacitors, the volume energy density of the power storage device 1 is 49.75 Wh / L (99.5 Wh), which is about 60% lower than that of the power supply unit. However, this energy density is only an example in which 50% charging is in a fully charged state. In normal use, the volume energy density of the power storage device 1 is 93.5 Wh / L (187 Wh) at this volume ratio, and the power supply It will decrease by 25% compared with the part. The charging time required to charge the 187 Wh lithium ion battery is approximately 1.5 to 3 hours.

  However, in the power storage device 1 described above, that is, the power storage device 1 in which a lithium ion battery and a lithium ion capacitor are combined, 56 Wh out of 187 Wh is due to the lithium ion capacitor and is rapidly increased by the capacity of the lithium ion capacitor. Charging becomes possible. Specifically, when charging a lithium ion capacitor having a volumetric energy density of 56 Wh, charging (full charge) is sufficiently completed in several tens of seconds. In addition, in order to charge the lithium ion battery of the same capacity | capacitance (56Wh), the charging time of 1.5 to 3 hours is required.

  As described above, the power storage device 1 according to this embodiment can be quickly charged in several tens of seconds. Even when the power storage device 1 is out of capacity (battery is exhausted), the rapid charging of the electric bicycle can be performed in a short time. Driving is possible. By such rapid charging (full charging of the lithium ion capacitor) in such a short time, for example, traveling at a speed of 10 km / h enables traveling at a distance of about 10 km.

  Thus, in the power storage device 1 of the present embodiment, rapid charging can be performed while securing a volumetric energy density (Wh / L) with a practical size (device volume).

-Other embodiments-
In the above example, the user is informed that the rapid charging of the power storage device 1 has been completed (the full charging of the capacitor 20 has been completed) by lighting the lamp. However, the present invention is not limited to this, The user may be informed that the quick charging has been terminated by the occurrence of the error or the display of characters. Further, two or all of the lamp lighting, the sound generation, and the character display may be combined to notify the user that the rapid charging is completed.

  In the above example, the volume ratio between the secondary battery (lithium ion battery) and the capacitor (lithium ion capacitor) is 7: 3, but the present invention is not limited to this. The ratio of the total capacity of the capacitor takes into account, for example, the amount of charge that enables the target load to be used due to rapid charging, and the fact that the capacitor is preferentially used to suppress the number of times the secondary battery is charged and discharged. And may be set appropriately.

  In the above example, DC power is output from the power storage device to the load. However, the present invention is not limited to this, and when the load is driven by AC power, the output control unit 32 is supplied with DC / DC power. An AC converter may be provided to output AC power to the load.

  The power storage device of the present invention can be effectively used as a power source for vehicles such as an electric bicycle, an electric wheelchair, and an electric golf cart, a power source for an electric tool, etc., and an electronic device such as a mobile phone and a personal computer, It can also be used as a power source for vehicles such as electric vehicles (EV) and hybrid vehicles (HV).

DESCRIPTION OF SYMBOLS 1 Power storage device 10 Secondary battery 20 Capacitor 30 Control part 31 Input control part 32 Output control part 33 [Capacitor-> secondary battery] Charge control part 34 SOC detection part 35 SOC detection part 40 Display part (notification part)
42 Quick charge end lamp 101 Load 201 AC power source 202 Renewable energy power generation device 203 Micro energy recovery device

Claims (6)

A power storage device capable of charging and discharging,
A secondary battery, a capacitor, and a controller that controls charging and discharging of the secondary battery and the capacitor;
The control unit controls charging in the order of charging of the capacitor and charging of the secondary battery when charging the power to the power storage device, and discharging the power from the power storage device when controlling the charging of the capacitor. A power storage device configured to control discharge in the order of discharge and discharge of the secondary battery. The power storage device according to claim 1,
A power storage device comprising: a notifying unit for notifying that a capacitor is fully charged when the capacitor to be charged first is fully charged when charging the power to the power storage device. The power storage device according to claim 1 or 2,
The control unit discharges power from the secondary battery when the capacity of the capacitor is exhausted, and when the capacitor is charged and fully charged during discharge of the secondary battery, A power storage device that performs control to switch discharge from the secondary battery to the capacitor. In the electrical storage apparatus as described in any one of Claims 1-3,
The power storage device, wherein the control unit is configured to charge the secondary battery from the capacitor when there is no load. In the electrical storage apparatus as described in any one of Claims 1-4,
The power storage device, wherein the control unit performs control to maintain a charge capacity of the secondary battery below a predetermined set upper limit value lower than a fully charged state of the secondary battery. In the electrical storage apparatus as described in any one of Claims 1-5,
The power storage device is connectable to at least one of a renewable energy power generation device and a minute energy recovery device, and charges the capacitor using electric power from at least one of the renewable energy power generation device and the minute energy recovery device. A power storage device configured to perform.

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