JPH09167633A - Distributed sodium sulfur battery module system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain high performance and size reduction of a system by connecting the prescribed number of cells all in series to each other, and outputting voltage by performing orthogonal transformation by an inverter. SOLUTION: Sodium sulfur cells 11 are connected by 70 to 125 all in series to each other, and are formed as a sodium sulfur battery aggregate 1, and it is housed in a heat insulating vessel 2. DC discharge voltage is set to about 140 to 250V, and orthogonal transformation is performed by an inverter 3, and it is set as AC effective voltage, and about 100V or about 200V is outputted. In this way, when the cells 11 are used by connecting them all in series to each other, a circulating current in a module by unbalance of a battery characteristic is eliminated, and capacity and efficiency of the module can be maintained high. AC effective output voltage is set to about 100V, and an AC effective electric current is set to 30A or 60A at its maximum, and a compact system can be obatained for domestic use by using cells which can respectively discharge an electric current of 12 to 22A or 24 to 50A for about 4 hours.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distributed sodium-sulfur battery module system suitable for use in a small-scale power storage device such as a household load conditioner or an emergency power source.

[0002]

2. Description of the Related Art Sodium-sulfur batteries that use sodium for the negative electrode and sulfur for the positive electrode have attracted attention because of their high efficiency and energy density, and are expected to be used in electric power storage devices and electric vehicles. In a conventional sodium-sulfur battery module system, for example, JP-A-3-15506
No. 0, JP-A-3-214570, JP-A-4-357675, etc., storage batteries are connected in series and parallel and housed in a heat-insulating container, and these are connected individually or in series and parallel to each other. It is considered to be used as a power storage device via However, when the cells are connected in parallel, there is a problem in that the battery characteristics become unbalanced due to variations in battery characteristics and temperature variations in the heat insulation container, and circulating current flows inside the module, resulting in reduced capacity and reduced efficiency of the module. . In addition, when applying the sodium-sulfur battery module system to a general household, it is necessary to make a match with the existing power wiring equipment, but there is no characteristic or scale suitable for this in the conventional module system. It was difficult to apply it for business.

Further, an electric power storage device using a lead battery instead of a sodium-sulfur battery has been put into practical use and is used as an emergency power source or an uninterruptible power source. When applying this to a general household, The voltage fluctuates depending on the charging / discharging state and deterioration, the charging / discharging efficiency is low due to self-discharge of the battery, and the battery life is short. There wasn't.

[0004]

The object of the present invention, except for the above-mentioned drawbacks of the prior art, is suitable for use in small-scale power storage devices such as load conditioners for home use and emergency power supplies. It is to provide a high-performance and compact distributed sodium-sulfur battery module system.

[0005]

In order to achieve the above object, the dispersed sodium-sulfur battery module system of the present invention stores a plurality of sodium-sulfur single cells in a heat insulating container and is connected to a power system via an inverter. In the distributed sodium-sulfur battery module system, about 70 or more and about 125 or less of the unit cells are all connected in series to set a DC discharge voltage of about 140 V or more and about 250 V or less, and orthogonal conversion is performed by the inverter to obtain an AC effective voltage. About 100
The first feature is to output V or approximately 210V. The second feature is that the AC effective output current from the module system is 30 A or 60 A at maximum. The module system is about 100
AC effective voltage of V, AC effective current maximum 30A or 60
When outputting A, all the single cells capable of discharging the current of 12 to 22 A or 24 to 50 A at a voltage of 1.9 V or more for about 4 h are used in series, and the AC effective voltage of about 210 V is applied to the AC effective current maximum. When outputting 30A or 60A, all the cells that can discharge a current of 24 to 50A or 50 to 90A at a voltage of 1.9V or more for about 4h are connected in series, and after orthogonal conversion, step up with a transformer as needed. It is desirable to do. Further, it is preferable that the total amount of sodium constituting the module system is less than 10 kg and the total amount of sulfur is less than 100 kg. Furthermore, the amount of sodium and sulfur contained in the unit cell and the volume of the cell are about 50 when the battery can discharge a current of 12 to 22 A for about 4 h.
~120g, about 100~300g, about 500cm ³ or less,
About 1 for a battery that can discharge a current of 24 to 50 A for about 4 h
00～300G, about 200 to 700 g, about 1000 cm ³ or less, the time of about 4h discharging batteries current 50~90A about 200-500 g, about 400～1200G, about 200
The volume of the heat insulating container may be 0 cm ³ or less, and
AC effective output voltage from the inverter is about 100V
When the AC effective current is 30A or 60A at the maximum, it is 1501 or less or 300l or less, and when the AC effective output voltage is about 210V and the AC effective current is 30A or 60A at the maximum, 3001 or less or 600l or less, respectively. You can

In the distributed sodium-sulfur battery module system of the present invention, since all the single cells are connected in series and used, there is no possibility that a circulating current will flow in the module due to the imbalance of the battery characteristics. High capacity and efficiency can be easily maintained. Further, since the DC output voltage of the battery is configured to be about 140 V or more to about 250 V or less, it is a withstand voltage range of a general-purpose semiconductor element, and an inverter having a simple system configuration using a general-purpose semiconductor element is used. Orthogonal or AC / DC conversion can be performed, and an AC effective voltage of 100 V or 210 V boosted as necessary can be output with high conversion efficiency. In the case of AC 100V, the peak voltage is about 140V, but the modulation factor of the PWM type inverter using a semiconductor element such as IGBT can be easily adjusted to a range of about 1.0 to 0.6. A DC voltage of about 140 to 250 V can be easily converted into an AC effective voltage of about 100 V (peak voltage of about 140 V) using an inverter. Further, in the case of 210 V AC, the voltage may be stepped up by a transformer if necessary after orthogonal conversion by an inverter. In order to make the output waveform close to a sine wave, the smaller the modulation rate is, the more preferable it is, and many low capacity batteries may be used.
On the other hand, in order to make the module system compact, it is only necessary to increase the modulation rate and use a large capacity battery. Further, in the module system of the present invention, since the maximum value of the AC effective current is 30 A or 60 A, the existing electric wiring of a general household can be used as it is. When used as a small-scale power storage device, it is generally desirable that the module system be as compact as possible. Especially when used for general household use, it is desired that the size is the minimum necessary. Considering the application for general household use, the maximum effective current of 30 A or 60 A is usually 4 hours or less per day, so the battery used may be one with a discharge capacity of 4 h at the rated current. The module system can be made compact by using single cells of various capacities. Therefore, when connecting to an AC 100V system, a voltage of 1.9V or more and a current of 12 to 22
When 70 or more and about 125 or less single cells capable of discharging A or 24 to 50 A for about 4 hours are connected to an AC 210 V system, a voltage of 1.9 V or more and a current of 24 to 50 A or 50 to 9 are used.
About 70 or more single cells capable of discharging 0A for about 4h, about 125
The following may be connected in series and, after orthogonal transformation, may be stepped up by a transformer as needed. When a battery with a discharge current of 12 to 45 A is used, a small semiconductor element can be used because the semiconductor element used for the inverter has a relatively small current capacity. On the other hand, when a battery having a discharge current of 50 to 90 A is used, there is an advantage that the module system can be easily made compact.

Further, since the open-circuit voltage of sodium-sulfur batteries is generally 2.1 V or less, about 70 or more and about 125 or less unit cells having a discharge voltage of 1.9 V or more are connected in series, and orthogonal conversion is performed by the inverter. When the output voltage is 210V, the effective voltage of AC is 100V ± 5V or 210V comparatively easily without using a special voltage adjustment circuit such as a booster circuit by boosting with a transformer as needed.
± 10V, which is sufficient voltage accuracy for general use ± 5
% Can be secured. In addition, when a battery having a current of 24 to 50 A is used, there is an advantage that it can be easily applied to 100 V system / 210 V system by changing / not attaching a transformer.

The sodium-sulfur battery has a current efficiency of 100%.
In principle, it is an extremely excellent battery, and even if the power loss for keeping the battery warm is taken into consideration, the charging / discharging efficiency at the DC end is 85%.
As described above, it is easy to secure a charge / discharge efficiency of 75% or more at the AC end. Further, since the change in the open circuit voltage due to charging / discharging is relatively small, the output voltage from the inverter can be easily kept substantially constant. Furthermore, since the life expectancy can be expected to be 15 years or more, when used as an electric power storage device for general households, by storing night-time electric power and using it in the daytime, it is possible to reduce the power generation facilities and reduce the electric power charges for general households. It is extremely effective in terms of saving.

The amounts of sodium and sulfur contained in the unit cell of the sodium-sulfur battery of the present invention are 12 to 2 respectively.
In the case of a battery that can discharge 2A for about 4h, about 50 to 120
g, about 100 to 300 g, about 24 to 50 A of current for about 4 h when the battery can discharge about 100 to 300 g, about 200 to
In the case of a battery capable of discharging 700 g and a current of 50 to 90 A for about 4 h, it may be about 200 to 550 g and about 400 to 1200 g. In this case, the volume of the single cell is 12 to 2 discharge current.
For a 2 A battery, approximately 500 cm ³ or less, discharge current 24-
About 1000 cm ³ or less when 45A of the battery discharge current 5
In the case of a battery of 0 to 90 A, it can be 2000 cm ³ or less. As a result, the volume of the heat insulating container for accommodating the battery is 1501 or less or 30 when the AC effective output voltage is 100 V and the AC effective current is 30 A or 60 A at the maximum.
0l or less, when the AC effective output voltage is 210V and the AC effective current is 30A or 60A at the maximum, 3001 or less or
Can be as compact as 600 l or less.

Furthermore, about 7 cells of a discharge current of about 22 A are used.
In a module system in which five AC power supplies have an AC effective output voltage of about 100 V and an AC effective current of 30 A at the maximum, the amounts of sodium and sulfur contained in the heat insulating container can be less than 10 kg or less than about 100 kg, respectively.
Designated quantity of dangerous substances (sodium: 10) specified in Article 10 of the Fire Service Act and the Cabinet Order concerning the regulation of dangerous substances
kg, sulfur: 100 kg) or less, which is also an advantage that the required fire extinguishing equipment can be significantly reduced. For this purpose, for example, up to 125 batteries with a Na content of less than 80 g, N
If the amount of battery is 120 g, the number of batteries may be 83 or less.
In both module systems with AC effective output voltages of about 100 V and 210 V, the amount of sulfur in the heat insulating container can be less than or equal to the specified amount of dangerous substances, and there is an advantage that the fire extinguishing equipment for sulfur can be reduced.

Instead of storing all the cells in one heat-insulating container and connecting them in series, they are divided into a plurality of heat-insulating containers in which the quantity of dangerous substances per unit is less than the specified quantity, and they are connected in series and stored. Can be connected in series. In this way, the fire safety of the system can be increased. In this case, it is desirable that the sum of the volumes of the plurality of heat insulating containers be within the above-mentioned predetermined range. Needless to say, a plurality of the dispersed sodium-sulfur battery module systems of the present invention may be connected in parallel to supply a current of 60 A or more to the system.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments.

FIG. 1 shows an example of the configuration of the dispersed sodium-sulfur battery module system of the present invention. In the figure,
1 is an assembly of 70 to 125 sodium-sulfur batteries 11 connected in series. In this example, sodium 55 to 120
g, sulfur 110 to 300 g, unit cell volume of 500 cm ³ or less, and voltage of 1.9 V or more and current of 22 to 12 A can be discharged for 4 h. Reference numeral 2 denotes a heat insulating container that accommodates these batteries and has a volume of 1501 or less. A vacuum heat insulating container is usually used because of its excellent heat insulating performance. The inside of this heat insulating container is heated by an electric heater (not shown) provided inside. Reference numeral 3 denotes an inverter, which includes a semiconductor switching element 31 such as a MOSFET element or an IGBT element, a transformer 32, a coil 33 for waveform adjustment, a capacitor 34, and the like. Here, the semiconductor switching element 31 constitutes a bridge for orthogonal conversion or AC / DC conversion. After conversion, an effective voltage of about 100 V and a maximum effective current of 30 A are supplied as an AC output to a power system (not shown) via a transformer.

In another example, the sodium-sulfur battery of FIG. 1 has 100-300 g of sodium and 200-300 g of sulfur.
700 g, the battery volume 1000 cm ³ or less, voltage 1.9V
With the above, 70 single cells capable of discharging current 50 to 24 A for 4 h
Up to 125 pieces are connected in series and housed in a heat insulating container 2 having a volume of 3001 or less. Further, by using a step-up transformer as the transformer 32 and stepping up the voltage by about twice, an effective voltage of about 210 V and a maximum effective current of 30 A are supplied to the power system as an AC output.

As a specific example, a capacity of 88 Ah per line
(4h discharge 22A), the rated output of about 42W, sodium content 116 g, sulfur content 240 g, sodium-sulfur battery of volume 470 cm ^3, or, in a volume 176Ah (44A 4h
Discharge), the rated output of about 84W, sodium content 232 g, sulfur content 480 g, using a sodium-sulfur battery of volume 900 cm ^3, 85 present, or 90 present each battery connected in series, the vacuum insulated container of each volume 1351 or 2501 Then, a module of about 3.6 kW or about 7.6 kW was obtained. Each of the obtained modules was connected to the same inverter as shown in FIG. 1 to obtain a distributed sodium sulfur battery module system with an AC effective voltage of 100V or 210V. Each module is maintained at 330 ℃, DC current 22A discharge 4h, 8.8A charge 10h, or DC current 44A discharge 4h, 17.6A 10h.
The charging / discharging efficiency at the DC end when charged was 91%, the efficiency including the heater loss for heat retention was 89%, and the efficiency at the AC end was 80% when considering the reciprocating efficiency of the inverter of 90%. . In this way, because there is no circulating current in the module, the efficiency of the module can be increased, high efficiency can be maintained for a long period of 15 years or more with a simple circuit configuration, compact structure, etc. It has been found that a power storage device suitable for use can be realized. further,
The maximum effective current at the AC end is 30A, and it can be connected to the existing electrical wiring in each home as it is and can discharge for 4 hours at the maximum current, so it is just suitable for each home to store nighttime power and use during the daytime. , It turned out that the system is suitable for saving electricity charges.

[0016]

According to the present invention, a highly efficient and compact structure of a distributed sodium-sulfur battery module system is realized, and a small-scale power storage such as a load conditioner for home use or an emergency power supply is realized. It is suitable for use in a device.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a dispersed sodium sulfur battery module system of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Sodium-sulfur battery assembly, 2 ... Insulation container, 3 ... Inverter, 11 ... Sodium-sulfur battery, 31 ... Semiconductor switching element, 32 ... Transformer, 33 ... Coil, 34 ...
Capacitors.

Claims (7)

[Claims] 1. A distributed type sodium-sulfur battery module system in which a plurality of sodium-sulfur single batteries are housed in a heat insulating container and connected to a power system through an inverter, all of which are about 70 or more and about 125 or less in series. And a DC discharge voltage of about 140 V or more and about 250 V or less, and the inverter performs orthogonal conversion to output about 100 V or about 210 V as an AC effective voltage, which is a distributed sodium-sulfur battery module system. 2. The dispersed sodium-sulfur battery module system according to claim 1, which outputs a maximum of 30 A or a maximum of 60 A as an AC effective current. 3. The battery according to claim 1, wherein when the AC effective output voltage is about 100 V and the AC effective current is 30 A or 60 A at maximum, the electric current is 12 as the unit cell.
Dispersed sodium-sulfur battery module system, characterized by using ~ 22A or 24-50A capable of discharging for about 4h. 4. When the AC effective output voltage is approximately 210 V and the AC effective current is 30 A or 60 A at maximum in the claim 1 or 2, the current of each unit cell is 24.
Dispersed sodium-sulfur battery module system characterized by using up to 50 A or 50-90 A capable of discharging for about 4 h and boosting it with a transformer as needed after orthogonal transformation. 5. The dispersed sodium-sulfur battery module system according to claim 1, wherein the total amount of sodium constituting the module system is less than 10 kg, and the total amount of sulfur is less than 100 kg. 6. The battery according to claim 3, wherein the amount of sodium, the amount of sulfur, and the battery volume of the unit cell are about 50 to 50 when the battery can discharge a current of 12 to 22 A for about 4 h, respectively.
120 g, about 100 to 300 g, about 200 to 700 g, about 1000 cm ³ or less, the time of about 4h discharging batteries current 50~90A about 200～550G, about 400 to 1200
Dispersion-type sodium-sulfur battery module system characterized by g and about 2000 cm ³ or less. 7. The volume of the heat insulation container according to claim 1 or 2, when the AC effective output voltage from the inverter is about 100 V and the AC effective current is 30 A or 60 A at the maximum, 1501 or less or 300 l or less, respectively. AC effective output voltage is about 210V and AC effective current is maximum 30A or 6
Dispersed sodium-sulfur battery module system, which is 3001 or less or 600 l or less at 0 A, respectively.