JP2000021457A - Capacitor system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently charge/discharge a battery at a safe temperature by charging a capacitor means with night electric power, arranging a temperature measuring means, a cooling means and a heating means, operating the cooling means only at discharge time by supplying electric power from the capacitor means, and operating the heating means only at charging. SOLUTION: A composite battery is formed by connecting respective lithium ion secondary batteries 1a, 1b, 1c in series with each other to constitute a capacitor means 2 of a capacitor system being charged has night electric power and discharging except for night electric power supply time. In charging/discharging processing, first the ambient temperature of the batteries 1a, 1b, 1c is measured by a temperature sensing means 4, and when the temperature is higher than a first lighting temperature or more, air is blown by rotating a battery cooling fan 12 when the capacitor system discharges so as to cool the respective batteries with air. When the battery ambient temperature is not more than a second limiting temperature, electric current is carried to one or more in heating means 6a, 6b, 6c when the capacitor system is charged so as to heat the batteries 1a, 1b, 1c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a power storage system. More specifically, the present invention relates to a power storage system including a battery pack using a plurality of lithium ion secondary batteries as power storage means.

[0002]

2. Description of the Related Art At least two or more lithium ions 2
Japanese Patent Application Laid-Open No. 5-62714 discloses that in a battery pack composed of a secondary battery, an abnormal rise in the temperature of the battery surface is detected and the circuit is cut off to protect the battery pack.

[0003]

However, since the battery pack of the conventional lithium ion secondary battery was assumed to be used for portable equipment such as a video camera and a personal computer, the temperature of the battery was detected by detecting the abnormal temperature of the battery. It has been used for protection against user's safety against the rise, and no consideration has been given to the fact that the charge / discharge performance of the battery decreases due to a decrease in ambient temperature. Especially in the middle and large-sized power storage systems that are installed outdoors and are mainly charged at night and discharged during the day, the power is stored at night when the ambient temperature is low and charging is difficult, and the battery is discharged during the day when the ambient temperature is high and the battery temperature tends to rise. Therefore, there is a problem that the conventional technology is effective for protection but cannot effectively utilize the performance of the battery.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a power storage system in which at least two or more lithium ion secondary batteries are used as power storage means. Temperature measuring means for measuring a temperature, cooling means which operates when a temperature equal to or higher than a first limit temperature preset by the temperature measuring means is measured, and temperature equal to or lower than a second limit temperature preset by the temperature measuring means. And a heating means that is activated when the measurement is performed.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings, but these do not limit the scope of the present invention. Hereinafter, an example of a stationary power storage system that charges with nighttime power and discharges at times other than nighttime power supply will be described. FIG. 1 is a block diagram of a stationary power storage system using a three-parallel battery pack, and reference numerals 1a, 1b, and 1c denote lithium ion secondary batteries (hereinafter referred to as batteries). The respective lithium ion secondary batteries are connected in series to constitute a power storage means 2 of a power storage system as an assembled battery, and both terminals of each of the batteries 1a, 1b, 1c are connected to a general control unit 3, and the general control unit 3 each battery 1
The terminal voltages of a, 1b, and 1c are constantly monitored. Reference numeral 4 denotes a temperature measuring means for detecting the ambient temperature of the batteries 1a, 1b, 1c. Both ends of the temperature measuring means 4 are connected to the overall control unit 3, and the batteries 1a, 1
The ambient temperature of b and 1c is constantly monitored. A charge / discharge control unit 5 is connected to the positive electrode side of the batteries 1a, 1b, 1c connected in series, and the charge / discharge control unit 5 controls the batteries 1a, 1b.
Switching of charging and discharging to b and 1c and bidirectional control of voltage and current during charging and discharging are performed.

The charge / discharge control unit 5 is connected to the general control unit 3, and operates according to a signal from the general control unit 3. Heating means 6a, 6b, 6c and heating control means 7a, 7b,
7c and heating circuits 8a, 8b, 8
c is connected. Discharge circuits 11a, 11b, and 11c each having a configuration in which discharge resistors 9a, 9b, and 9c and discharge control means 10a, 10b, and 10c are connected in series are connected to the respective batteries 1a, 1b, and 1c in parallel. .

The heating circuit 8a, 8b, 8c and the discharge circuit 11a, 11b, 11c are controlled by the overall control unit 3.
The temperature measured by the temperature measuring means 4 and each battery 1a, 1b, 1c
Is controlled in accordance with the inter-terminal voltage. On the input / output side of the charge / discharge control unit 5, a series circuit of a battery cooling fan 12 and a fan control unit 13 includes a positive power line 14 and a negative power line 1.
5, the fan control unit 13 is connected to the general control unit 3 and is controlled by the general control unit 3. The positive power line 14 and the negative power line 15
Is connected to the voltage conversion unit 16 and the voltage conversion unit 16
Performs AC / DC bidirectional conversion and voltage level conversion during charge / discharge.

The voltage conversion unit 16 is connected to a system switching unit 17. The system switching unit 17 has a midnight power connection terminal 18 for charging and a load connection terminal 19 for discharging.
The system switching unit 17 switches the connection between the voltage conversion unit 16 and the midnight power connection terminal unit 18 or the load connection terminal unit 19 during charging and discharging. The voltage conversion unit 16 and the system switching unit 17 are connected to the overall control unit 3 and are controlled by the overall control unit 3. FIG. 2 is an arrangement plan view showing an example of arrangement of main components of the present embodiment. It should be noted that this layout diagram shows an example, and does not limit the scope of the present invention. Temperature measuring means for measuring the ambient temperature of the batteries 1a, 1b, 1c in the vicinity of the battery 1b, wherein the batteries 1a, 1b, 1c are arranged side by side at a position facing the battery cooling fan 12. 4
Are provided, and heating means 6a, 6b, 6c are arranged close to each of the batteries 1a, 1b, 1c.
Each of the batteries 1a, 1b, 1c can be heated in substantially the same manner.

The battery cooling fan 12 has a blowing guide 21
Are attached so that the batteries 1a, 1b, and 1c can be air-cooled in substantially the same manner. These heating means 6
a, 6b, 6c, battery cooling fan 12, batteries 1a, 1
control circuit unit 22 including overall control unit 3 for controlling b and 1c
Are disposed on the side surfaces of the batteries 1a, 1b, 1c which are not likely to be affected by the heat generated by the batteries 1a, 1b, 1c and the liquid leakage, and the heat generated by the control circuit unit 22 is also applied to the batteries 1a, 1b, 1c. Try not to affect.

Next, the basic operation of this embodiment will be described with reference to the operation flow of FIG. The operation flow of FIG. 3 is a partial flowchart of the charge / discharge processing unit of the power storage system of the present embodiment. In this embodiment, this operation flow is periodically repeated in the entire processing flow. In the charging / discharging process in the present embodiment, first, the ambient temperature of the batteries 1a, 1b, 1c is measured by the temperature measuring means 3 (23), and then the batteries 1a, 1
The voltage between the terminals b and 1c is measured (24). It is checked whether or not the temperature measured by the temperature measuring means 3 is within a normal temperature range where charging and discharging can be performed in advance (25). It is checked whether the temperature is within the normal range (26). If the temperature or the voltage between the terminals is out of the normal range, it is regarded as abnormal and a predetermined abnormality handling process is performed (27). Move on to processing.

If the inter-terminal voltages of the batteries 1a, 1b, 1c are all within the normal range, it is checked whether the inter-terminal voltages of the batteries are all equal to or higher than a preset dischargeable voltage value.
(28) If each battery has a dischargeable voltage, it is checked whether or not to discharge (29). If any of the terminal voltages of the batteries 1a, 1b, 1c is discharged at a dischargeable voltage value or more, a predetermined discharging process is performed after the charging stop process (30) (32), and the batteries 1a, 1b, 1c. If any one of the terminal voltages falls below the dischargeable voltage value or does not discharge, a discharge stop process is performed (31).

After the discharge is stopped, it is checked whether or not the voltage between the terminals of each battery is within the chargeable voltage range (33), and if any of the voltages between the terminals of each battery is within the chargeable voltage range, charging is performed. It checks whether or not (34), performs a predetermined charging process when charging (35), and stops a predetermined charging when not charging and when any of the voltage between terminals of each battery is out of the chargeable voltage range. Processing is performed (36). Although not described in this operation flow, in the present embodiment, charging is performed with nighttime power, so charging is performed only when nighttime power is supplied.

After completion of any of the above-described discharge processing, charging processing or charging stop processing, it is determined whether or not the battery ambient temperature measured by the temperature measuring means 3 is higher than a preset first limit temperature (37). , Battery ambient temperature is first
If the temperature is higher than or equal to the limit temperature, it is checked whether the power storage system is discharging (38). If discharging is in progress, the battery cooling fan 12 is turned on to blow air (39) and each battery is air-cooled. When the battery ambient temperature is lower than the first limit temperature and when the battery is not discharging, a process of stopping the battery cooling fan 12 is performed (40). After stopping the battery cooling fan 12, it is checked whether the battery ambient temperature is lower than a preset second limit temperature (41). If the battery ambient temperature is equal to or lower than the second limit temperature, the power storage system is checked. It is checked whether or not the battery is being charged (42). If the power storage system is being charged, a signal is issued from the overall control unit 3, and one or more of the heating control means 7a, 7b, 7c are turned on for heating. One or more of the means 6a, 6b, 6c are energized (43) to heat the batteries 1a, 1b and 1c.

At this time, by controlling the conductivity of the heating control means 7a, 7b, 7c in accordance with the magnitude of the value of the voltage between the terminals of each battery, the larger the voltage between the terminals of each battery, the greater the heating. The conductivity of the control means is increased, and the heating means 6
By adjusting the duty ratios of a, 6b, and 6c (44), and adjusting the amount of charge charged to each battery, the variation in the amount of charge between the batteries is corrected. In addition, when the power storage system is not charging, when the battery ambient temperature is higher than the second limit temperature, and when the battery cooling fan 12 is blowing during discharging, the heating control means 7a, 7b, 7c is activated. Then, the power supply to the heating means 6a, 6b, 6c is stopped to stop the heating of each battery (45).

After the heating of each battery is stopped, it is checked whether or not the magnitude of the inter-terminal voltage between the batteries has a variation exceeding a preset allowable value (46). If the variation is large, it is checked whether all the inter-terminal voltages of the batteries are equal to or higher than a preset dischargeable voltage and the battery ambient temperature is equal to or higher than a second limit voltage (47),
When the inter-terminal voltages of all the batteries are equal to or higher than the dischargeable voltage and the battery ambient temperature is equal to or higher than the second limit temperature, the discharge control means 10a, 1
0b, 10c to control the discharge circuits 11a, 11b, 1
The variation of the terminal voltage between the batteries is corrected by adjusting the duty ratio of 1c (48). After performing such processing, the processing proceeds to the next processing.

[0016]

According to the present invention, in a power storage system using a battery pack composed of at least two or more lithium ion secondary batteries as power storage means, temperature measurement means for measuring the temperature on the surface of the battery or around the battery; A cooling unit that operates when a temperature equal to or higher than a first limit temperature set in advance is measured by the temperature measurement unit; and a heating unit that operates when a temperature equal to or lower than a second limit temperature set in advance is measured by the temperature measurement unit. Since the battery is provided, the battery ambient temperature is measured, and the battery is heated or cooled, so that the battery can be charged and discharged at an efficient and safe temperature.

Since charging can be performed by nighttime power, charging can be performed by using nighttime power, which is cheap, and can be used during the daytime when the power rate is high, so that the power rate can be reduced. Also, the cooling means is configured to operate only at the time of discharging by supplying power from the power storage means, and the heating means is configured to operate only at the time of charging. In the daytime when the temperature is high, the cooling means can prevent a rise in the temperature of the battery beforehand, so that a highly safe power storage system can be supplied.

The greater the charge of the battery, the greater the danger of the battery. However, since the battery is supplied with power for cooling, the cooling power can be increased as the charge increases.
By increasing the safety and heating only during charging at night, which is an endothermic reaction and the ambient temperature of the battery is low, the battery can be fully charged, and the power for heating is supplied from nighttime power. Therefore, the charge amount of the battery is not reduced.

Further, a heating circuit in which the heating means and the heating control means are connected in series is provided in parallel with each battery constituting the power storage means, and the temperature is measured by the temperature measuring means and the voltage between the terminals of each battery is corresponded. Since the configuration is such that the current flowing through the heating means is adjusted, the current flowing through the heating means connected in parallel to the battery having a high inter-terminal voltage at a low temperature when the charge / discharge performance of the battery is low increases the terminal between the batteries. The charge / discharge performance of the battery can be improved by increasing the battery ambient temperature while correcting the variation of the inter-voltage.

In addition, a heating circuit and a discharging circuit are provided in parallel with each battery, so that the voltage between the terminals of the batteries is equal to or higher than a predetermined voltage value when each battery is charged, and the temperature measured by the temperature measuring means is set in advance. By configuring so that the discharge circuit provided in parallel to the battery is operated only when the temperature becomes equal to or higher than the predetermined temperature, even when the heating circuit is not operated, when the variation in the terminal voltage between the batteries occurs. Variation can be corrected.

Further, when the variation between batteries is large even during the operation of the heating circuit, the variation can be corrected in a short time by simultaneously operating the discharge circuit, and the allowable range of the variation of each battery constituting the assembled battery. In particular, in a power storage system that uses a large number of batteries with a large number of batteries connected in series, the allowable variation range of the battery capacity can be increased, the yield during battery production can be improved, and the cost of the power storage system can be reduced. is there.

[Brief description of the drawings]

FIG. 1 is a block configuration diagram of a stationary power storage system that uses a three-in-one parallel battery pack charged by nighttime power as power storage means.

FIG. 2 is a schematic layout plan view of a stationary power storage system using a battery pack having three straight batteries as power storage means.

FIG. 3 is a partial flowchart of a charge / discharge processing unit of the power storage system.

[Explanation of symbols]

1a, 1b, 1c: lithium ion secondary battery, 2: power storage means, 4: temperature measurement means, 5: charge / discharge control unit, 6a, 6
b, 6c heating means, 7a, 7b, 7c heating control means, 8a, 8b, 8c heating circuit, 11a, 11b, 1
1c: discharge circuit, 12: battery cooling fan, 18: midnight power connection terminal.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H029 AJ02 CJ02 5H030 AA10 AS01 BB14 BB21 FF24 FF43 FF44 5H031 AA09 KK03 KK08

Claims (5)

[Claims] In a power storage system using a battery pack composed of at least two or more lithium-ion secondary batteries as power storage means, a temperature measurement means for measuring the temperature of the surface of the battery or the surroundings of the battery; A cooling unit that operates when a temperature equal to or higher than a set first limit temperature is measured; and a heating unit that operates when a temperature equal to or lower than a second limit temperature set in advance by the temperature measurement unit is measured. Power storage system. 2. The power storage system according to claim 1, wherein the power storage means is charged with nighttime power. 3. The cooling means is configured to operate only at the time of discharging by supplying power from the power storage means, and the heating means is configured to operate only at the time of charging.
A power storage system according to claim 1. 4. A heating circuit in which a heating means and a heating control means are connected in series is provided in parallel with each of the secondary batteries constituting the power storage means, and corresponds to a temperature measured by the temperature measuring means and a voltage between terminals of each battery. The power storage system according to any one of claims 1 to 3, wherein the power supply system is configured to adjust a current flowing through the heating means. 5. A discharge circuit is provided for each battery in parallel with a heating circuit, and when each battery is charged, the voltage between terminals of the battery is equal to or higher than a predetermined voltage value and the temperature measured by the temperature measuring means is a predetermined temperature. The power storage system according to claim 4, wherein a discharge circuit provided in parallel with the battery is operated only when the temperature is equal to or higher than the temperature.