JP2003217679A - Discharging method for secondary battery, storage battery and air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stably increase the dischargeable quantity of a secondary battery. <P>SOLUTION: In discharging a secondary battery such as a lead storage battery, intermittent discharging is performed while a primary pause is repeated every time a battery voltage 12 is lowered to a discharging end voltage 13, and discharging is performed while a discharging current 11 is reduced by steps every time discharging is started through the primary pause. Thus, the discharging rate as the whole can be lowered. Generally, when the discharging rate is lowered, the dischargeable quantity is increased. This phenomenon is used to obtain a larger dischargeable quantity from the secondary battery as compared with the case of continuously discharging at a high rate, and the dischargeable quantity can be stably increased. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a secondary battery discharging method, a storage battery adopting the method, and an air conditioner.

[0002]

2. Description of the Related Art There is a power storage type air conditioner (power storage air conditioner) which performs air conditioning operation during the daytime by using nighttime electric power, which has a low power load and is cheap. This electricity storage air conditioner does not require energy conversion to heat using night power, and has an advantage that the excellent function of the air conditioner can be fully exerted by using electricity as it is in the daytime.

A storage battery (secondary battery) used for a storage air conditioner is required to have a large capacity, a long life, and a low cost as required specifications. At present, the most suitable storage battery is considered to be a lead storage battery. .

[0004]

In general, the amount of discharge (capacity) that can be taken out from a battery varies depending on the discharge current. This discharge current is determined by the relationship between the discharge rate, the rated capacity [Ah] and the discharge time. Specifically, when the discharge rate (for example, the discharge rate when a battery having a rated capacity of 70 Ah is ideally completely discharged in 1 hour is expressed as "1CA") (high-rate discharge), The capacity that can be taken out from the battery is reduced.

For example, in the case of a lead storage battery, during discharge, the active material on the surface of the electrode plate reacts with sulfuric acid in the vicinity of the surface of the electrode plate, the active material changes to lead sulfate, the specific gravity of sulfuric acid decreases, and the discharge voltage decreases.

[0006] Here, the discharge current is large, the electrode plate of the deep in the reaction does not proceed sulfate ion (SO ₄ ^{- -)} voltage to keep up also moving decreases rapidly, reaching the early discharge end voltage . In other words, the high-rate discharge does not effectively use the active material and the electrolytic solution that the storage battery has, which reduces the capacity that can be taken out from the battery.

Further, when a plurality of unit cells are connected in series and discharged by the assembled battery, the unit cell voltage at the time of discharging varies depending on the capacity variation of each battery, but when discharging more than that capacity, The battery is in a deep discharge state and may not return to its original capacity even when charged. As described above, the deep discharge is the most important factor for accelerating the deterioration of the lead battery, so that the utmost care must be taken.

FIG. 5 is a diagram showing a corresponding curve of the battery voltage and the discharged electricity quantity when the rated capacity is 60 Ah and the discharge rate is about 0.33 CA (about 20 A in terms of discharge current).
Also has a rated capacity of 60 Ah and a discharge rate of 1 CA
The respective figures showing the corresponding curves of the battery voltage and the amount of discharged electricity in the case of (about 60 A in terms of discharge current) are shown. In each figure, a plurality of corresponding curves are shown as -10
This is because they are shown under respective temperature environments of ° C, 0 ° C, 25 ° C and 45 ° C.

For example, the discharge rate of a storage air conditioner is shown in FIG.
As shown in, about 0.33 CA (about 20 in terms of discharge current)
Compared with the case of setting in A), when performing high rate discharge as shown in FIG. 6, the voltage drop at the end of discharge is remarkable, and the discharge amount that can be taken out may be insufficient as compared with the low rate discharge condition.

Further, in setting the battery voltage (referred to as "discharge end voltage") which is the condition for ending the forced discharge, it is necessary to end the discharge just before all the batteries are brought into the deep discharge state in consideration of the unit cell variation. However, in order to do this, it is necessary to individually manage and measure the voltage of the unit cell.

However, when the number of cells is large, measuring the discharge end voltage for all the cells makes the control circuit as hardware very complicated and costly.

For this reason, generally, the voltage of an assembled battery in which a plurality of batteries are connected in series is measured to control the discharge end voltage and the like. In such measurement and management with the voltage of the assembled battery, considering the variation of each battery, the set value of the discharge end voltage is set considerably higher than the average value (cell average value x number of cells). However, if it does so, it is assumed that the rated discharge amount cannot be secured because the discharge time becomes short, and the running merit of the power storage system decreases.

Therefore, an object of the present invention is to provide a secondary battery discharge method, a storage battery and an air conditioner which can stably increase the discharge amount.

[0014]

[Means for Solving the Problems] In order to solve the above problems,
According to the first aspect of the present invention, the discharge is performed intermittently with the primary pause interposed, and the discharge current (11) is reduced stepwise every time the discharge is restarted after the primary pause. .

The invention according to claim 2 is the method for discharging a secondary battery according to claim 1, wherein the battery voltage (12) is set to a predetermined discharge end voltage (13) when the secondary battery is discharged. In the first step of comparing with, and in the first step, each time it is determined that the battery voltage has decreased to reach the discharge end voltage, the discharge is temporarily stopped for a predetermined stop time, and A second step of storing the discharge current (11) immediately before the primary pause, and a second step of discharging at a discharge current lower than the discharge current immediately before when restarting the discharge of the secondary battery after the primary pause. The third step is repeated, and the first to third steps are repeated.

According to a third aspect of the present invention, there is provided the method for discharging a secondary battery according to the second aspect, wherein after the second step,
When the discharge amount of the secondary battery reaches the rated discharge amount, the discharge of the secondary battery is terminated when the battery voltage subsequently drops to the discharge end voltage.

The invention according to claim 4 is the method for discharging a secondary battery according to claim 2 or 3, wherein the discharge current is reduced to a predetermined minimum current value after the second step. When it reaches, the discharge of the secondary battery is terminated when the battery voltage subsequently drops to the discharge end voltage.

A fifth aspect of the present invention is the method for discharging a secondary battery according to any one of the second to fourth aspects, wherein the predetermined rest time is such that the battery voltage is a certain value or more. It is set for a sufficient time to rise.

A sixth aspect of the present invention is the method for discharging a secondary battery according to any one of the second to fifth aspects, wherein the secondary battery (220) is charged for one day. It is set to be limited to a predetermined first time zone in which the power demand is low, and the discharge time of the secondary battery is set to include a predetermined second time zone in which the power demand is high in one day. The secondary battery is used together with the other power source.

The invention according to claim 7 is the method for discharging a secondary battery according to any one of claims 1 to 6, wherein the secondary battery assists a power supply to an inverter of an air conditioner. It is to be discharged in order to supply electricity.

The invention described in claim 8 is the method for discharging a secondary battery according to any one of claims 1 to 7, wherein the secondary battery is a lead storage battery.

According to a ninth aspect of the present invention, the secondary battery discharging method according to any one of the first to eighth aspects is adopted, and the secondary battery is provided.

The invention according to claim 10 is provided with an inverter (102) and a secondary battery (220) and uses a commercial power source in a predetermined first time zone during which a power demand is small in a day. An air conditioner that supplies power to the inverter together with the commercial power source in a predetermined second time zone during which a large amount of power is demanded during the day while charging the secondary battery, The secondary battery (220) is
The discharge is performed intermittently with the primary pause in between, and the discharge current (11) is gradually reduced every time the discharge is restarted after the primary pause.

The invention according to claim 11 is the air conditioner according to claim 10, wherein the secondary battery is discharged.
The battery voltage (12) is compared with a predetermined discharge end voltage (13), and each time it is determined that the battery voltage has dropped to reach the discharge end voltage, the battery is temporarily stopped for a predetermined pause time and The discharge current (1
1) is stored, and when the secondary battery is restarted to be discharged after the primary pause, discharging is performed with a discharge current lower than the discharge current immediately before.

The invention described in claim 12 is the air conditioner according to claim 11, wherein when the discharge amount of the secondary battery reaches a rated discharge amount, the battery voltage is thereafter discharged. The discharge of the secondary battery is terminated when the voltage reaches the final voltage.

The invention described in claim 13 is the air conditioner according to claim 11 or claim 12, wherein when the discharge current reaches a predetermined minimum current value, the battery voltage is thereafter increased. At the time when the discharge end voltage is lowered,
The discharge of the secondary battery is terminated.

According to a fourteenth aspect of the present invention, in the air conditioner according to the eleventh aspect, the predetermined rest time is set to a time sufficient for the battery voltage to rise above a certain value. It is something.

The invention according to claim 15 is the air conditioner according to any one of claims 10 to 14, wherein the secondary battery is a lead storage battery.

[0029]

1 is a block diagram showing the configuration of a storage battery unit 200 in which a secondary battery discharging method according to an embodiment of the present invention is adopted, and an air conditioning system equipped with the storage battery unit 200. Is.

The air conditioning system is an outdoor unit 10
0, an indoor unit 300 is also provided. The outdoor unit 100 includes a compressor 103, and the indoor unit 300 performs an air conditioning operation on an interior (not shown) using a refrigerant (not shown) compressed here.

The storage battery unit 200 includes a storage battery (secondary battery) 220 to be charged / discharged, a bidirectional converter 210 that executes charging / discharging, and a charge / discharge control unit 230 that controls charging / discharging. ing.

The outdoor unit 100 further includes an AC / DC converter 101 and an inverter 102. AC
The / DC converter 101 is, for example, a three-phase AC commercial power source 4
00, AC / DC conversion, and inverter 1
02 or the bidirectional converter 210, DC power is supplied. The inverter 102 is operated by using the DC power supplied from the bidirectional converter 210 and the DC power supplied from the AC / DC converter 101 together to drive the compressor 103.

The storage battery unit 200 receives the DC power from the AC / DC converter 101 only in a time zone (first time zone) where the electricity demand is low and the electricity rate is low, for example, at night, and the storage battery incorporated therein. 220 is charged via bidirectional converter 210. At this time, the inverter 10
2 is not driven.

On the other hand, the time zone in which the inverter 102 is operated is set to include the time zone (second time zone) from daytime to the evening when the power demand is high in one day, and the storage battery 220 is set in this time zone. Is not charged, AC / D
DC power is supplied to the inverter 102 (discharge of the storage battery 220) together with DC power supplied by the C converter 101.

The storage battery 220 is constructed as an assembled battery, for example, and is constructed by connecting a plurality of unit cells 221 as lead storage batteries in series.

FIG. 2 is a circuit diagram showing a configuration of a portion related to charging / discharging of the storage battery 220. Here, the inverter 102
However, the configuration of supplying DC power from the AC / DC converter 101 is omitted.

The bidirectional converter 210 includes a charging converter 211 for charging and a converter 212 for discharging.
And a charging / discharging changeover switch 213 that is switched between when the storage battery 220 is charged and when it is discharged. That is, at the time of charging, under the control of the charge / discharge control unit 230, the AC / DC converter 101 is controlled by the charging converter 211 via the charging / discharging changeover switch 213.
The storage battery 220 is charged with the electric power obtained from Further, at the time of discharging, under the control of the charge / discharge control unit 230, the storage battery 220 is discharged to the inverter 102 by the discharge converter 212 via the charge / discharge changeover switch 213.

The charge current and the voltage of the storage battery 220 are monitored by the charge / discharge control section 230 as needed. The charge / discharge control unit 230 has a function of causing the bidirectional converter 210 to control a charge / discharge current to a constant current, a function of switching a charge / discharge current value, and a function of managing integration of charge / discharge amounts. These functions are shown in FIG. 2 as a "constant current control function", a "charge / discharge current switching function", and a "charge / discharge amount integration management function", respectively.

In the above-mentioned storage battery (secondary battery) 220, generally, the capacity that can be taken out by continuous high-rate discharge is small, but if the discharge rate is lowered, a larger amount of discharge can be taken out. Focusing on this, as shown in FIG. 3, the discharge of the storage battery 220 is intermittently performed in a part of the time zone T1, and the discharge current is gradually reduced step by step at each of these intermittent discharges. Then, the discharge rate as a whole is reduced to obtain a large amount of discharge.

Here, the storage battery 220 is an AC commercial power source 40.
Storage battery 2 because it assists the power supply from 0
Even if the discharge from 20 is limited to a part of the time zone T1, is temporarily stopped, or the discharge current is gradually reduced, the driving of the inverter 102 is not hindered. In addition, a part of the time zone T1 is set to include a time zone (second time zone) from daytime to evening in which a large amount of power is demanded in one day.

The vertical axis in FIG. 3 represents the discharge current and battery voltage of the storage battery 220, the horizontal axis represents the time of day, and the thick solid line 11 represents the storage battery 220 as an assembled battery. The discharge current and the chain double-dashed line 12 are the storage battery 220 as an assembled battery.
And the alternate long and short dash line 13 indicate the discharge end voltage.

The specific operation will be described with reference to the flowchart of FIG. First, in step S01, it is determined whether or not it is the discharge time zone (the second time zone including the symbol T1 in FIG. 3) based on the time measurement by a timer (not shown) in the charge / discharge control unit 230, and the discharge time is determined. When it is determined that the band is present, the discharge is performed by the discharge control function (converter 212) (step S02). The discharge here does not necessarily have to be a high rate discharge.

Then, in step S03, the charge / discharge control unit 230 calculates an integrated value of the discharge current 11 of the storage battery 220 shown in FIG. 3 from the start of the time zone T1, and the integrated value is used as a discharge amount, for example, in advance in the ROM. It is determined whether or not the discharge amount has reached the predetermined rated discharge amount by comparing with the predetermined rated discharge amount stored in the above.

If the amount of discharge does not reach the rated amount of discharge in step S03, the process proceeds to step S04, and the charge / discharge control unit 230 lowers the battery voltage 12 of the storage battery 220 shown in FIG. Judge whether or not. When the battery voltage 12 has not reached the discharge end voltage 13, the processing from step S02 is repeated.

In step S04, when the rated discharge amount cannot be secured due to the high rate discharge of the storage battery 220 or the like, the battery voltage (discharge voltage) 12 of the storage battery 220 may drop to the discharge end voltage 13. Yes (reference numeral t in FIG. 3)
a). In this case, the charge / discharge control unit 230 determines to that effect, and proceeds to step S05, where the battery voltage of the storage battery 220 is 1
The discharge is temporarily stopped before 2 becomes lower than the discharge end voltage 13 (step S05).

At this time, the discharge rate immediately before the discharge is terminated for the primary pause is stored in a predetermined memory (for example, a nonvolatile memory such as SDRAM) in the charge / discharge control unit 230.

At this point, the storage battery 220 has no waiting time.
There is also a method to start the discharge from the battery, but as shown in FIG. 3, the battery voltage 12 is paused for a certain period of time to sufficiently increase the battery voltage 12 to a certain value or more (for example, 100 V or more as shown in FIG. 3) and then the discharge is restarted. By doing so, a larger amount of discharge can be earned. Further, when the assembled battery is used as the storage battery 220 in particular, it is desirable to sufficiently raise the battery voltage 12 once in order to reduce the possibility of the existence of cells that are deeply discharged. Therefore, as in the next step S06, the battery voltage 12 is sufficiently increased by performing a primary rest for a preset rest time of about 1 to 5 minutes from step S05 based on the time measurement result by the above-mentioned timer. After that, when the rest time ends, the process proceeds to the next step S07.

In step S07, it is determined whether or not the discharge rate immediately before the primary discharge pause stored in step S05 is the preset minimum rate. If it is higher than the minimum rate, step S08
Proceed to.

In step S08, for example, the discharge rate is lowered according to data such as a predetermined data table stored in advance in the ROM or the like, and the discharge is started at this lowered discharge rate.

After that, steps S02 to S0
The process of 8 is repeated. Specifically, by repeating the processing of step S02 to step S08, when the storage battery 220 is discharged, it is intermittently discharged while repeating the primary pause as shown in FIG. Then, the discharge current 11 is about 20 A, about 1 A each time the discharge is restarted after the primary pause.
7A, about 14A, about 11A, about 8A.

In this way, the discharge current 11 is gradually reduced, the discharge from the storage battery 220 is intermittently repeated, and the discharge is terminated when the rated discharge amount is completed in step S03.

Even when the discharge amount has not reached the rated discharge amount, when the discharge current 11 immediately before the primary discharge pause reaches the predetermined minimum current value in step S07, the discharge current 11 is further reduced. Therefore, the discharge of the storage battery 220 is ended. For example, in FIG. 3, the discharge current 11 of about 8 A is flowing out of the storage battery 220 when the discharge of the storage battery 220 is restarted after the fourth primary pause. However, when setting about 8 A as the minimum current value, ,
As shown in FIG. 3, the subsequent discharge from the storage battery 220 is stopped, and thereafter the inverter 10 is operated only by the AC commercial power supply 400.
2 will be driven.

As described above, the discharge of the storage battery 220 is performed intermittently with a pause, and the discharge current is reduced stepwise at each intermittent discharge. Can be reduced and a large amount of discharge can be obtained. Therefore, if this secondary battery discharge method is applied to a power storage air conditioner as an example,
When performing high-rate continuous discharge for a long time, such as during high cooling operation in summer, the battery voltage may drop rapidly at the end of discharge, so the discharge amount may not be secured, but this secondary battery discharge method ensures reliable discharge. The amount can be increased, which can contribute to securing the running merit of the storage air conditioner.

Further, when the assembled battery is used as the storage battery 220, the battery voltage 12 is once sufficiently raised by the primary pause of the discharge and then the discharge is restarted, so that there is a possibility that a deep discharge cell exists. Can be reduced.

In the above embodiment, a battery pack in which a plurality of unit cells 221 are connected in series is used as the storage battery 220, and the battery voltage 12 of the storage battery 220 as the battery pack is 12
Was compared with the end-of-discharge voltage 13 corresponding to this battery pack, and the discharge was paused, but the battery pack (storage battery 220)
The battery voltage may be compared with the end-of-discharge voltage for each of the unit cells 221 constituting the above to suspend the primary discharge.

Further, although the lead storage battery has been described as an example of the storage battery 220, it goes without saying that it can be applied to other secondary batteries.

[0057]

According to the invention described in claims 1 to 15, for example, a lead storage battery (claims 8 and 15)
When the secondary battery is discharged, the battery is intermittently discharged while repeating the primary pause, and is discharged while the discharge current is gradually reduced each time the discharge is restarted after the primary pause. Can be dropped. Therefore,
A large amount of discharge can be taken out from the secondary battery, and the amount of discharge can be stably increased as compared with the case of performing continuous high rate discharge.

In this case, claim 3, claim 4, claim 1
As described in 2 and claim 13, when the discharge amount of the secondary battery reaches the rated discharge amount and / or the discharge current reaches a predetermined minimum current value, the battery voltage thereafter decreases to the discharge end voltage. At that point, discharge of the secondary battery will end, so
It is possible to reduce the consumption of the secondary battery. In particular, as in claims 3 and 12, the discharge of the secondary battery is terminated before the discharge amount of the secondary battery becomes less than the rated discharge amount, so that the discharge amount can be secured at the rated discharge amount or more. There is.

According to the fifth and fourteenth aspects of the invention, the idle time of the secondary battery is set to a time sufficient for the battery voltage to rise above a certain value. Therefore, a larger amount of discharge can be earned. In particular, when the assembled battery is used as the storage battery, the battery voltage is once sufficiently raised by the primary pause of the discharge and then the discharge is restarted, so that the possibility of existence of a deep discharge cell can be reduced. It will be possible.

Claims 6 and 11 to 15
According to the invention described in (1), the secondary battery is used as an auxiliary of the AC commercial power source, and the charging time of the secondary battery is limited to the predetermined first time zone during which the power demand is small in one day. When setting the discharge time of the secondary battery to include the predetermined second time zone in which the power demand is large in one day, it is not possible to utilize the power so as to level the power demand. Also, the first demand is smaller than the second demand period when the power demand is high.
Since the electric power cost is generally cheaper in the time zone of 1, the secondary battery can be utilized as efficiently as possible when the cost is reduced.

Further, the present invention is particularly effective when applied to an air conditioner as in the seventh and eleventh to fifteenth aspects.

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of an air conditioner used in a secondary battery discharging method according to an embodiment of the present invention.

FIG. 2 is a block diagram showing an outline of an air conditioner used in a secondary battery discharging method according to an embodiment of the present invention.

FIG. 3 is a diagram showing a time transition of a discharge current and a battery voltage of a storage battery according to an embodiment of the present invention.

FIG. 4 is a flowchart showing a secondary battery discharging method according to an embodiment of the present invention.

FIG. 5 is a diagram showing a relationship between a battery voltage and a discharged electricity charge.

FIG. 6 is a diagram showing a relationship between a battery voltage and a discharged electricity charge.

[Explanation of symbols]

11 discharge current 12 Battery voltage 13 Discharge end voltage 200 storage battery unit 220 storage battery 221 cells 230 Charge / Discharge Control Unit 400 AC commercial power supply

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3L060 AA03 CC08 CC10 DD01 EE04                 5G003 AA01 BA03 CA01 CA11 DA07                       DA13 GB03 GB06 GC05                 5H030 AA04 AS03 AS06 BB21 FF42                       FF44

Claims (15)

[Claims] 1. A secondary discharge characterized by intermittently discharging with a primary pause, and reducing discharge current (11) stepwise every time the discharge is restarted after the primary pause. A method of discharging a battery (220). 2. The method for discharging a secondary battery according to claim 1, wherein a first step of comparing the battery voltage (12) with a predetermined discharge end voltage (13) when the secondary battery is discharged. And in the first step, each time it is determined that the battery voltage has decreased to reach the discharge cutoff voltage, the discharge is suspended for a predetermined suspension time, and the discharge immediately before the primary suspension is performed. A second step of storing a current (11); and when resuming discharge of the secondary battery after the primary pause,
A third discharge for discharging with a discharge current lower than the discharge current immediately before
And a step of repeating the above-mentioned first to third steps. 3. The method of discharging a secondary battery according to claim 2, wherein after the second step, when the discharge amount of the secondary battery reaches a rated discharge amount, the battery is then discharged. A secondary battery discharging method, characterized in that discharging of the secondary battery is terminated when the voltage drops to the discharge end voltage. 4. The method for discharging a secondary battery according to claim 2, wherein after the second step, when the discharge current reaches a predetermined minimum current value, A secondary battery discharging method, characterized in that discharging of the secondary battery is terminated when the battery voltage drops to the discharge end voltage. 5. The method of discharging a secondary battery according to claim 2, wherein the predetermined rest time is a time sufficient for the battery voltage to rise above a certain value. A method of discharging a secondary battery, wherein the method is set to. 6. The method for discharging a secondary battery according to claim 2, wherein the secondary battery (220) is charged at a predetermined time when the power demand is small in one day. Is set to be limited to the first time zone of, and the time of discharge of the secondary battery is set to include a predetermined second time zone of high power demand of one day, and the secondary battery is A method for discharging a secondary battery, which is used together with another power source. 7. The method of discharging a secondary battery according to claim 1, wherein the secondary battery discharges to supplementarily supply power to an inverter of an air conditioner. A method for discharging a secondary battery, comprising: 8. The discharging method for a secondary battery according to claim 1, wherein the secondary battery is a lead storage battery. 9. A storage battery (200) which employs the method for discharging a secondary battery according to any one of claims 1 to 8 and comprises the secondary battery. 10. An inverter (102) and a rechargeable battery (220) are provided to charge the rechargeable battery using a commercial power source in a predetermined first time period during which the power demand is low in one day. An air conditioner in which the secondary battery supplies power to the inverter together with the commercial power source in a predetermined second time zone during which a large amount of power is demanded in a day, the secondary battery (220) However, the air conditioner discharges intermittently with a primary pause, and discharges while gradually reducing the discharge current (11) every time the discharge is restarted after the primary pause. 11. The air conditioner according to claim 10, wherein the battery voltage (12) is compared with a predetermined discharge end voltage (13) when the secondary battery is discharged, and the battery voltage is the discharge voltage. Each time it is determined that the voltage has decreased to the final voltage, the battery is temporarily stopped for a predetermined pause time, the discharge current (11) immediately before the primary stop is stored, and the secondary battery of the secondary battery is stored after the primary stop. An air conditioner characterized by performing discharge with a discharge current lower than the discharge current immediately before when restarting discharge. 12. The air conditioner according to claim 11, wherein, when the discharge amount of the secondary battery reaches a rated discharge amount, the battery voltage thereafter drops to the discharge end voltage. Then, the discharge of the secondary battery is terminated, and the air conditioner. 13. The air conditioner according to claim 11 or 12, wherein when the discharge current reaches a predetermined minimum current value, then the battery voltage drops to the discharge end voltage. An air conditioner characterized by terminating the discharge of the secondary battery at the point of time. 14. The air conditioner according to claim 11, wherein the predetermined rest time is set to a time sufficient for the battery voltage to rise above a certain value. Harmony machine. 15. The air conditioner according to claim 10, wherein the secondary battery is a lead storage battery.