JP2000251931A - High temperature sodium secondary battery system and its operating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high temperature secondary battery system suitable for a power storage system used for load leveling and peak shifting purposes and also for unsteady operations such as for an emergency power supply, an uninterruptible power supply, a standby power supply and the like, and its operating method. SOLUTION: A storage container 3 constituting a part of plural temperature sodium secondary battery modules 1 and a storage container 3' constituting remaining modules have different heat insulation, and a part of the modules 1 and the remaining modules 1' are mutually connected through an AC/DC converter 6, 6'. Thereby, this system can be operated in complicated operating patterns as a dual purpose system for load leveling and peak shifting purposes, and also for unsteady operations such as operations for an emergency power supply, an uninterruptible power supply, a standby power supply and the like, while keeping the temperature range of the high temperature sodium secondary battery module, and load leveling for a power becomes possible by using it as a system for a load following operation, a dual purpose system for an emergency power supply or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-temperature sodium secondary battery system suitable for power storage and an operation method thereof.

[0002]

2. Description of the Related Art High-temperature sodium secondary batteries use sodium for the negative electrode and sulfur, selenium, tellurium, metal halide, etc. for the positive electrode, and have high efficiency and energy density. Use is expected. These secondary batteries have an operating temperature of about 30
In order to maintain the temperature at 0 ° C., the module is housed in an insulated container to constitute a module, and one or more of the modules are operated as a system combined with an AC / DC converter. In addition, since such a secondary battery module is normally operated repeatedly in a cycle of storing power during the night and discharging during the day,
The heat insulation during the operation of the battery, especially during the discharge, is taken into consideration to design the heat insulation performance of the storage container, and a device is designed to balance the amount of heat generated by the battery and the amount of heat released from the storage container during one cycle of operation per day. I have. These prior arts include Japanese Patent Application Laid-Open No. 9-2
Japanese Patent Application Laid-Open No. 19216 and Japanese Patent Application Laid-Open No. 5-110992 are known.

[0003]

In the above prior art, the system is used as a combined system of a load leveling operation operated at a constant charge / discharge output and a peak shift operation operated at a variable output corresponding to a load change. In this case, it is difficult to keep the battery temperature within a predetermined range both during the load leveling operation and during the peak shift operation because the discharge output of the battery greatly differs depending on the operation pattern. When this system is used for unsteady operation such as emergency power supply, uninterruptible power supply, or standby power supply, the insulation performance of the heat insulating container should be as large as possible in order to increase the efficiency of the entire system. It is desirable to reduce the required heater energy, but if the heat insulation performance is large, it is difficult to prevent the battery temperature from rising when the load leveling operation and peak shift operation are repeated, so both system efficiency can be improved and operation as a dual-purpose system can be achieved. It was difficult to do.

Further, in the conventional battery system, charging / discharging is not performed as on holidays, peak shifts are small in number of times in spring and autumn, and standby days are long, and emergency power supplies, uninterruptible power supplies, and standby power supplies are used. When the battery is used for standby at a high temperature without operating at all times, it is necessary to operate the heater provided in the heat insulating container at the time of standby to keep the battery at a predetermined temperature. There is a problem that the efficiency of the entire system is reduced.
On the other hand, if the heat loss during standby is reduced to suppress the energy loss, there is a problem that the battery temperature exceeds the allowable range due to heat generated during operation, and the battery life is shortened due to corrosion of the container and the like.

An object of the present invention is to solve the above-mentioned problems, and it is an object of the present invention to provide an emergency power supply for load leveling and peak shifting, or for load leveling and peak shifting. It is an object of the present invention to provide a high-temperature sodium secondary battery system suitable as a power storage system that also serves as a power storage device for an unsteady operation such as an uninterruptible power supply or a standby power supply, and an operation method thereof.

[0006]

In order to achieve the above object, a first high-temperature sodium secondary battery system according to the present invention comprises a high-temperature sodium secondary battery such as a sodium-sulfur battery and a module accommodating a high-temperature sodium secondary battery. A high temperature sodium secondary battery system in which a plurality of converters are combined with each other, wherein a storage container forming a part of the plurality of modules has a different heat insulating performance from a storage container forming the remaining modules. And a part of the module and the remaining modules are connected via an AC / DC converter. Here, the storage container is formed of a vacuum insulated container having at least two partitions, and the vacuum insulated container forming the part of the modules and the vacuum insulated container forming the remaining modules are defined by the degree of vacuum in the partition. Are desirably different. Alternatively, the storage container is constituted by a side wall, an upper wall, and / or a lower wall, and the heat insulating performance of the upper wall and / or the lower wall of the some modules is insulated by the upper wall and / or the lower wall of the remaining modules. Preferably, it differs from performance.

[0007] The first method for operating a high-temperature sodium secondary battery system of the present invention is characterized in that the operation pattern of some of the modules is different from that of the remaining modules. Specifically, the heat insulation performance of the storage container forming the part of the module is made smaller than the heat insulation performance of the storage container forming the remaining module, or the part of the module is used for the purpose of peak shift, Alternatively, the heat insulation performance of the storage containers of some of the modules is made larger than the heat insulation performance of the storage containers of the other modules, and the some modules are operated in an unsteady operation such as an emergency power supply, an uninterruptible power supply, or a standby power supply. It is preferably used for the purpose.

Further, the second high-temperature sodium secondary battery system of the present invention comprises a module comprising a high-temperature sodium secondary battery such as a sodium-sulfur battery and a module comprising a secondary battery other than the high-temperature sodium secondary battery. It is characterized in that it is connected via an AC / DC converter. Here, it is preferable that the secondary battery other than the high-temperature sodium secondary battery is a lead secondary battery, a lithium secondary battery, a nickel hydride secondary battery, or a nickel cadmium secondary battery. Further, the operation method of the second high-temperature sodium secondary battery system according to the present invention, wherein the operation pattern of the module comprising the high-temperature sodium secondary battery is the same as the operation pattern of the module comprising a secondary battery other than the high-temperature sodium secondary battery. Is specifically characterized in that a module comprising a secondary battery other than the high-temperature sodium secondary battery is used for an unsteady operation such as an emergency power supply, an uninterruptible power supply, or a standby power supply. preferable.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the first high-temperature sodium secondary battery system of the present invention, a storage container in which a part of a plurality of modules constituting the system and a remaining module have different heat insulation performance. The AC / DC converter is attached to each of the partial module and the remaining module, and the modules are connected to each other via the AC / DC converter. Therefore, the partial module and the remaining module are different from each other. It is possible to operate in accordance with the different operation patterns, and to have heat insulation performance suitable for each operation pattern. As a result, the power storage device for load leveling and peak shift is also used, or the power storage for non-stationary operation such as load leveling, peak shift and emergency power, uninterruptible power and standby power is used. Even in the case of a complicated operation pattern such as a dual-purpose system with the device, by appropriately selecting the operation patterns and the heat insulation performance of the above-mentioned some modules and the remaining modules, while maintaining the battery temperature range appropriately, Driving patterns can be achieved. Specifically, in the case of a dual-purpose system for load leveling and peak shift, the heat insulation performance of some of the modules is made relatively small, and a peak shift operation corresponding to a load change is performed. It is sufficient to perform the load leveling operation with a substantially constant output of approximately 8 hours of discharge and approximately 8 to 10 hours of charge with relatively large adiabatic performance. In the case of the peak shift operation, the discharge time is generally shorter than that of the load leveling operation, but the peak of the discharge output is generally higher. Even if the integrated amount of the discharge amount (average discharge output × time) is the same, the output from the battery is the same. Although the calorific value is larger than in the load leveling operation, the difference in the heat insulation performance of the modules as described above allows the above-mentioned some modules and the remaining modules to operate while keeping the battery temperature within an appropriate range. can do. On the other hand, in the case of a dual-purpose system for load leveling and for non-stationary operation such as for emergency power supply, uninterruptible power supply or standby power supply, the insulation performance of some of the modules is relatively large to perform non-stationary operation. Then, the heat insulation performance of the remaining modules may be made relatively small, and the load leveling operation may be performed. In the case of unsteady operation such as for emergency power supply, uninterruptible power supply, or standby power supply, the charging period and the rest period from one discharge to the next discharge can be generally longer than those of load leveling operation. At the end of the time, the thermal design should be such that the maximum allowable temperature is not exceeded, and the heat insulation performance of the module should be increased to lower the temperature slowly. By doing so, it is possible to reduce the heater input for maintaining the battery temperature at an appropriate temperature during a halt, thereby increasing the efficiency of the entire system.

In the first high-temperature sodium secondary battery system of the present invention, a vacuum insulated container having at least a double partition is used as a storage container constituting a module, and the degree of vacuum in the partition of some of the modules is reduced. If a method different from the degree of vacuum of the remaining modules is adopted, different heat insulating performances can be provided using the vacuum heat insulating container having the same structure, and there is an advantage that the manufacture of the vacuum heat insulating container is simplified. Further, the storage container is constituted by a side wall, an upper wall and / or a lower wall, and the heat insulation performance of the upper wall and / or the lower wall of the part of the module is insulated by the upper wall and / or the lower wall of the remaining module. Using a method different from the performance, if the thermal design is performed so that heat is mainly radiated from the upper surface and / or the lower surface of the storage container that constitutes the part of the modules and / or the remaining modules, There is an advantage that a temperature difference is hardly generated between the plurality of batteries arranged. If a temperature difference occurs between the parallel batteries, a difference occurs in the characteristics of the batteries and an internal circulating current flows, which may cause a change in the capacity of the module. You can avoid problems.

Embodiment 2 In a second high-temperature sodium secondary battery system of the present invention, a module including a high-temperature sodium secondary battery such as a sodium-sulfur battery and a secondary battery other than the high-temperature sodium secondary battery are provided. Each of the modules is connected via an AC / DC converter, and the former module and the latter module are operated in different operation patterns from each other, so that they can be used for load leveling and peak shift, or for load leveling. It can be used as a combined system for non-steady-state operation such as power supply for emergency shift, peak shift, and emergency power supply, uninterruptible power supply, and standby power supply, and can easily achieve operation of a complicated operation pattern. In addition, as a secondary battery other than the high-temperature sodium secondary battery, a lead secondary battery, a lithium secondary battery, a nickel hydride secondary battery, or a nickel cadmium secondary battery is used, and a module composed of these batteries is used as an emergency power supply. , An uninterruptible power supply, a reserve power supply, etc. Lead rechargeable batteries, lithium rechargeable batteries, nickel-metal hydride rechargeable batteries, or nickel cadmium rechargeable batteries have the advantage of being able to operate at room temperature, eliminating the need for a heat insulating container or heater to keep the batteries warm and simplifying the system configuration. is there. However, these batteries have a relatively short life for repeated operation compared to high-temperature sodium secondary batteries. Therefore, high-temperature sodium secondary batteries are required for load leveling and peak shift operation that require repeated operation on a daily basis. It is desirable to use a battery module.

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

FIG. 1 shows a configuration example of a high-temperature sodium secondary battery system of the present invention. In the figure, reference numerals 1, 1 'denote modules accommodating a high-temperature sodium secondary battery, which accommodate a plurality of high-temperature sodium secondary batteries 2, 2' arranged in a plane direction and a plurality of high-temperature sodium secondary batteries. It comprises storage containers 3 and 3 'and heaters 4 and 4' provided inside the storage containers. Reference numerals 5 and 5 'denote electric wirings, and the high-temperature sodium secondary battery modules 1 and 1' are connected to the system wiring 8 via the AC / DC converters 6 and 6 'and the insulating transformers 7 and 7' by these electric wirings. Have been. Further, 9 is a control device for controlling the operation of the AC / DC converter. As can be seen from this figure, the thicknesses of the upper and lower walls of the storage containers 3 and 3 'are different from each other, and as a result, the heat insulation performance is different. Although not shown, a vacuum insulated container having the same structure is used as the storage containers 3 and 3 '.
The degree of vacuum may be different between 3 and 3 'so that the heat insulation performance is different. With this structure, by operating the high temperature sodium secondary battery modules 1 and 1 'with different operation patterns, the battery temperature level can be appropriately maintained, and the load leveling and peak shift can be combined, or the load leveling can be performed. This makes it possible to operate in a complex pattern, such as a system that is used for non-steady-state operation such as power supply for peak shift and emergency power supply, uninterruptible power supply, and reserve power supply.

Although not shown, either the high-temperature sodium secondary battery module 1 or 1 'of FIG. 1 is replaced with a lead secondary battery, a lithium secondary battery, a nickel hydride secondary battery or a nickel cadmium battery. A secondary battery module other than a high-temperature sodium secondary battery such as a secondary battery can also be used. In this case, a secondary battery module other than the high-temperature sodium secondary battery does not require a heat insulating container or a heater.

FIG. 2 shows an example of an operation method of the high-temperature sodium secondary battery system of the present invention. The vertical axis of the figure is the power consumed by the system wiring, the horizontal axis is the time, and a and a 'are respectively. The discharge patterns b and b 'of the secondary battery modules indicate charge patterns of these modules. For example, in the high-temperature sodium secondary battery system of FIG. 1, a module 1 having a relatively small heat insulation performance is operated in a discharge pattern a and a charge pattern b having a relatively large discharge output and a short discharge time, and has a relatively large heat insulation performance. 1 'may be operated with a discharge pattern a' and a charge pattern b 'having a relatively small discharge output and a long discharge time. The heat generated by the battery at the time of discharging is mainly determined by the heat loss due to the internal resistance of the battery. If the internal resistance of the battery is R and the discharge current is I, the heat loss W 'is given by the following equation (1).

W ′ = I ² R (1) On the other hand, assuming that the electromotive force of the battery is E, the discharge output W is expressed by equation (2).

W = (E−IR) × I (2) Therefore, even if the integrated amount of discharge amount (average discharge output × discharge time) is the same, if the discharge output is large as in a, the discharge time Heat generation becomes larger than a '. In this case, the module 1 having a small heat insulation performance of the module is replaced with the patterns a and b.
By performing the peak shift operation as shown in FIG. 2 and performing the load leveling operation as shown in patterns a 'and b' of the module 1 'having a large adiabatic performance, the battery temperature of each module is maintained in an appropriate range as shown in FIG. In addition, the high-temperature sodium secondary battery system can be operated as a whole following load fluctuations.

FIG. 3 shows another example of the operation method of the high-temperature sodium secondary battery system of the present invention. The vertical axis of the figure shows the discharge power and charge power of each module, and the horizontal axis shows the time. c and c 'represent discharge patterns of the respective modules, and d and d' represent charge patterns. In this case, as shown in FIG. 1, the module 1 having a small heat insulating performance is operated in the patterns c and d, and the battery temperature that has risen due to the battery heat generated at the time of discharging is cooled during the charging time or the standby time, and the discharging of the next day is started. It is designed to return to the original temperature by the time, while the module 1 'having a large heat insulating performance is used for unsteady operation patterns c' and d 'for emergency power supply, uninterruptible power supply and standby power supply.
I just need to drive. In the case of unsteady operation, the charge period and the rest period from one discharge to the next discharge can be generally long, so the thermal design should not exceed the maximum allowable temperature at the end of the discharge time, and the heat insulation performance of the module should be improved. By increasing the temperature and slowly lowering the temperature, it is possible to reduce the heater input for maintaining the battery temperature at an appropriate temperature at the time of suspension, thereby increasing the efficiency of the entire system. In this case, instead of the module 1 'of FIG. 1, a secondary battery module other than a high-temperature sodium secondary battery such as a lead secondary battery, a lithium secondary battery, a nickel hydride secondary battery, or a nickel cadmium secondary battery. May be used.

FIG. 4 shows an example of the structure of a high-temperature sodium secondary battery module used in the present invention. The components denoted by the same reference numerals as those in FIG. 1 have the same contents. Here, the storage container 3
For the reason that the heat insulation performance is excellent, a vacuum heat insulating container in which a gap between the metal double walls is filled with a heat insulating material (not shown) and the gap is evacuated is used. It has a structure in which a box-shaped lid constituting the upper wall 33 is covered on a box-shaped container main body composed of 32. Also, 1
0 is a metal plate to which the heater 4 is fixed, 11 is an insulating plate separating the metal plate 10 and the electric wiring 5, 12 is an insulating table separating the battery 2 and the lower wall 32 of the vacuum heat insulating container, and 13 is an electric wiring 5
It is an insulating material that electrically insulates the side wall 31 and the upper wall 33 of the vacuum heat insulating container. Further, reference numeral 20 denotes insulating particles such as dry sand, which are filled between the cells to enhance the safety and uniformity of the module. Here, by maintaining a high degree of vacuum on the side wall 31 of the vacuum insulated container and controlling the degree of vacuum on the upper wall 33 and / or the lower wall 32, the heat insulation performance differs as in the modules 1 and 1 'in FIG. It is possible to obtain a storage container.

As a specific example, the capacity per one piece is about 480 W
h, using a sodium-sulfur battery with a rated output of about 60 W, 216 batteries were arranged in a vacuum insulated container having a length of about 1 m, a width of about 1.5 m, and a height of about 0.6 m in a planar direction, and stored in FIG. A module with a capacity of about 100 kWh with a structure similar to that shown was obtained. In addition, an aluminum bus bar was used as electric wiring, insulated with glass wool, and taken out of the vacuum insulated container. The degree of vacuum in the side wall and the lower wall of the vacuum insulated container of one module is set to 0.001 atm and the degree of vacuum in the upper wall is set to 0.05 atm.
By adjusting the degree of vacuum in the side wall to 0.001 atm, two types of modules having the same structure and different heat insulating performances were obtained.

The obtained two types of modules are connected to the system wiring via an AC / DC converter and an insulating transformer, respectively, and one of the modules is charged and discharged according to the patterns a and b in FIG. Charge input peak 3
0 kW), and the other module can be operated in accordance with the load change in the system wiring by performing the charge / discharge operation (discharge output peak 12.5 kW, charge input peak 16 kW) in the pattern of a 'and b' in FIG. Met. The battery temperature is 310 ° C. at the start of discharge and the maximum temperature rise is 30 ° C., which is within the allowable temperature range of the battery. 3
After returning to 10 ° C., it was possible to operate continuously every day.

[0022]

According to the present invention, while maintaining the battery temperature range of the high-temperature sodium secondary battery module properly, it can be used for both load leveling and peak shifting, or for load leveling and peak shifting. It is possible to operate in a complicated operation pattern such as a system that is shared with a non-stationary operation such as a power supply, an uninterruptible power supply, or a standby power supply. As a result,
Power leveling can be effectively performed as a load following operation system or an emergency power supply system.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration example of a high-temperature sodium secondary battery system of the present invention.

FIG. 2 is a diagram showing an example of an operation method of the high-temperature sodium secondary battery module of the present invention.

FIG. 3 is a diagram showing an example of an operation method of the high-temperature sodium secondary battery module of the present invention.

FIG. 4 is a diagram showing a configuration example of a module containing a high-temperature sodium secondary battery used in the present invention.

[Explanation of symbols]

1, 1 ': module, 2, 2': high temperature sodium secondary battery, 3, 3 ': container, 4, 4': heater, 5,
5 ': electric wiring, 6, 6': AC / DC converter, 7, 7 ': insulating transformer, 8: system wiring, 9: control device, 31: side wall, 32: lower wall, 33: upper wall.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H029 AJ00 AJ12 AK05 AL13 AM15 BJ00 BJ02 BJ06 BJ21 BJ23 BJ25 HJ00 HJ15 5H031 AA01 AA02 AA03 AA05 AA09 CC01 CC05 CC09 HH00 HH06 KK02

Claims (10)

[Claims] 1. A high-temperature sodium secondary battery system in which a plurality of modules accommodating a high-temperature sodium secondary battery in a storage container and a plurality of AC / DC converters are combined. The constituent container has a different heat insulation performance from the constituent containers constituting the remaining modules, and the part of the modules and the remaining modules are connected via an AC / DC converter, respectively. High temperature sodium secondary battery system. 2. The storage container according to claim 1, comprising a vacuum insulation container having at least two partition walls, wherein the vacuum insulation container forming the partial module and the vacuum insulation container forming the remaining module. And a high-temperature sodium secondary battery system characterized in that the degree of vacuum in the partition walls is different. 3. The storage container according to claim 1, wherein the storage container comprises a side wall, an upper wall and / or a lower wall, and the heat insulating performance of an upper wall and / or a lower wall of the partial module is the remaining capacity. A high-temperature sodium secondary battery system, which is different from the heat insulating performance of an upper wall and / or a lower wall of a module. 4. A high-temperature sodium secondary battery characterized in that a module comprising a high-temperature sodium secondary battery and a module comprising a secondary battery other than the high-temperature sodium secondary battery are respectively connected via an AC / DC converter. Battery system. 5. A secondary battery other than the high-temperature sodium secondary battery according to claim 4, wherein the secondary battery is a lead secondary battery, a lithium secondary battery,
A high-temperature sodium secondary battery system, which is one of a nickel hydride secondary battery and a nickel cadmium secondary battery. 6. A plurality of modules in which a high-temperature sodium secondary battery is stored in a storage container, and some of the modules and the remaining modules are connected via an AC / DC converter, respectively.
An operation method of the high-temperature sodium secondary battery system, wherein an operation pattern of the some modules is different from an operation pattern of the remaining modules. 7. The heat insulation performance of the storage container forming the part of the module according to claim 6 is made smaller than the heat insulation performance of the storage container forming the remaining module, and the part of the module has a peak shift. A method for operating a high-temperature sodium secondary battery system, which is used for a purpose. 8. The heat insulation performance of the storage container forming the part of the module according to claim 6 is made larger than the heat insulation performance of the storage container forming the remaining module, and the part of the module is operated in an unsteady state. A method for operating a high-temperature sodium secondary battery system, wherein the method is used for the purpose of (1). 9. An operation pattern of a module comprising a high-temperature sodium secondary battery, wherein a module comprising a high-temperature sodium secondary battery and a module comprising a secondary battery other than the high-temperature sodium secondary battery are connected via an AC / DC converter, respectively. The operation method of the high-temperature sodium secondary battery system is different from the operation pattern of a module including a secondary battery other than the high-temperature sodium secondary battery. 10. A method for operating a high-temperature sodium secondary battery system, comprising using a module comprising a secondary battery other than the high-temperature sodium secondary battery according to claim 9 for the purpose of unsteady operation.