JP2003234132A - Heating device of collective battery composed of sodium- sulfur cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent temperature distribution of unit cells of a sodium-sulfur cell from becoming heterogeneous in a process of raising temperature even when a collective battery is down-sized and reduced in weight in a heating device of the collective battery composed of the sodium-sulfur cells. <P>SOLUTION: In this device, a tabular heating device 7 integrated by arranging electric-insulating plate materials 9, 10 at both faces of an heating wire 8 is installed at the peripheral wall face of a battery housing case 1, and if a plurality of independent heating wires is arranged nearly in parallel, it is advantageous in disconnection. <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 heating device for an assembled battery composed of sodium-sulfur batteries.

[0002]

2. Description of the Related Art Generally, a battery storage case of a sodium-sulfur battery is composed of a case body having an upper opening and a lid sealed to the opening. In this battery storage case, one set or a plurality of sets of battery blocks in which a large number of single cells of sodium-sulfur batteries are connected in a predetermined arrangement are stored. Further, the battery storage case is stored in a vacuum heat insulation container for keeping heat. That is, as shown in FIG. 5, the battery storage case 1 is a rectangular container, and the lid 2 is sealed on the open upper surface thereof. A large number of unit cells 3 are housed in the battery housing case 1, and the unit cells 3 are connected by a connection terminal 4 and a parallel connection line 5 to form an assembled battery. In addition, each cell 3 in the battery storage case 1
Insulating sand is filled in the space between the cells to fix the cells 3 so as not to sway, and at the same time improve the safety of the cells. Furthermore, the battery storage case 1 with the lid 2 attached
The whole is housed in a heat insulating container 6.

Since the assembled battery composed of this sodium-sulfur battery is operated at a high temperature of 300 ° C. or higher, it is necessary to raise the temperature to that temperature and maintain it at a temperature suitable for charging and discharging the battery. is there. Therefore, the battery storage case 1
On the outer peripheral surface thereof, several electric heaters 11 are installed at regular intervals in the height direction, and the electric heater 11 controls the temperature in the battery storage case 1.

[0004]

In the above-mentioned conventional assembled battery, the battery storage case 1 is made of a durable iron plate or steel plate, and an insulating material layer is provided between the battery storage case 1 and the battery block. In some cases, even if a small number of electric heaters 11 are installed on the outer peripheral surface of the battery storage case 1 at intervals, the temperature gradient is relaxed before reaching the battery block, so unless rapid heating is performed, The temperature distribution did not become non-uniform. However, in order to reduce the size and weight of the battery, the battery storage case 1
Needs to be thin and the gap between the battery block and the battery storage case 1 must be small. In addition, once the temperature is raised, it is not intended to be used at that temperature for a certain period of time, but if it is desired to store it at room temperature and heat it quickly when necessary, to shorten the time required to raise the temperature. First, it is necessary to increase the electric power of the electric heater 11. In such cases,
In particular, in the temperature rising process, the temperature distribution becomes uneven between the portion where the electric heater 11 is installed and the portion where the electric heater 11 is not installed on the outer peripheral surface of the battery storage case 1, and the locally heated single piece is heated. In the battery 3, the thermal stress generated at that time may be concentrated. Further, in the conventional assembled battery, a cylindrical electric heater 11 having a relatively large diameter is often used, and when the electric heater 11 is attached to the outer peripheral surface of the battery storage case 1, the battery storage case 1 However, the heat conduction between the electric heater 11 and the battery storage case 1 is insufficient, and the electric heater 1
There was a problem that 1 reached the end of life early.

Further, a single cell 3 of a sodium-sulfur battery
Generally has a diameter of 3-5 cm, as shown in FIG.
It is sealed in a vertically elongated metal cylinder. That is, the α-alumina ring 1 is attached to the upper end of the solid electrolyte tube 12.
3 is joined by glass solder, and this α-alumina ring 13
A negative electrode lid 15 is thermocompression-bonded to the upper surface of the same through an aluminum or aluminum alloy layer 14 which is a bonding material, and a positive electrode lid 16 is thermally bonded to the lower surface thereof in the same manner. A negative electrode terminal 17 is welded to the negative electrode lid 15, and a negative electrode pipe 18 serving as a negative electrode current collector is welded through the center of the negative electrode terminal 17, and a metal fiber 19 is disposed below the negative electrode pipe 18. The solid electrolyte tube 12 is inserted into the solid electrolyte tube 12, and the inside of the solid electrolyte tube 12 is evacuated from the negative electrode pipe 18 while keeping the temperature at about 150 ° C. After vacuum filling, the upper end of the negative electrode terminal 17 is sealed to form a negative electrode structure. Then, this negative electrode structure is inserted into a battery case 22 that also functions as a positive electrode current collector, in which a cylindrical sulfur molded body 20 is inserted and a positive electrode current collector terminal 21 is welded, and its upper end is the positive electrode lid 16 It is manufactured by vacuum welding. Such unit cells 3 are assembled in parallel in a standing state to form a battery block.
When the bottom area of the battery block is large and the height is relatively small, it is rational to heat from the bottom surface because of the structure, but when the bottom area is small and the height is large, the heat transfer area on the side surface Is advantageously used. However, in order to safely raise the temperature with the conventional electric heater 11, it is necessary to increase the dimensional margin for relaxing the thermal gradient.

[0006]

In order to solve the above-mentioned problems, the invention according to claim 1 is a battery housing case in which a plate-like heating device in which electrically insulating plate materials are arranged on both surfaces of a heating wire is integrated. It is an assembled battery composed of sodium-sulfur batteries installed on the peripheral wall surface.

The invention according to claim 2 is the assembled battery according to claim 1, in which a plurality of independent heating wires are arranged substantially in parallel.

As a result, the heating device can reduce the gradient of the temperature distribution on the surface, and can uniformly heat the unit cells housed in the battery housing case from the side surface in the height direction.
Therefore, only some of the unit cells are not overheated, and the concentration of thermal stress on them can be alleviated. Further, even when two or more battery storage cases are stacked to form an assembled battery, it is heated uniformly from the side surface of the unit cell in the height direction. Further, since the heating wire has a smaller space than the electric heater installed in the conventional assembled battery, there is also an effect that the efficiency of the accommodation space for accommodating the heating device is improved.

If a plurality of independent heating wires are arranged substantially parallel to each other in the heating device, even if one of them is disconnected, it operates without any trouble, which is advantageous for long-term use. The heating power can be adjusted by selecting the number of heating wires.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on its embodiments.

FIG. 1 is a schematic diagram of an assembled battery composed of a sodium-sulfur battery according to an embodiment of the present invention. As shown in FIG. 1, the battery storage case 1 is a rectangular container, and a lid 2 is sealed on the open upper surface thereof. A large number of unit cells 3 are housed in the battery housing case 1, and the unit cells 3 are connected by a connection terminal 4 and a parallel connection line 5 to form an assembled battery. In addition, each cell 3 in the battery storage case 1
Insulating sand is filled in the gaps between the cells so as to fix each unit cell 3 so as not to sway and at the same time enhance the safety of the cells. Furthermore, the battery storage case 1 with the lid 2 attached
The whole is housed in a heat insulating container 6 to form an assembled battery.

FIG. 2 is a view showing the installation of the heating device, in which the heating wire 8 constituting the heating device 7 is inserted and integrated between the two electrically insulating plate members 9 and 10. And
The heating device 7 is installed inside the battery storage case 1 on the side surface of the unit cell 3 which constitutes the battery block so as to cover the peripheral wall surface.

As shown in FIG. 3, if the heating wire 8 is thin and long and is arranged in a zigzag or meandering manner, it can be arranged in a wide area with high density and without taking thickness, so that space can be saved. It can be used effectively. Further, as shown in FIG. 4, if a plurality of heating wires 8 are arranged substantially parallel to each other, heating power can be adjusted by selecting the number of heating wires 8 and one heating wire is disconnected. However, it can be heated with another heating wire. The heating power can also be adjusted by dividing one heating wire and providing a lead terminal in the middle.

If the assembled battery is long, it is possible to efficiently heat it by installing the heating device 7 between the battery blocks that compose the assembled battery. It is also possible to omit the installation of the heating device 7 in.

It is also possible to design the assembled battery so that the heating device 7 is installed on the outer side surface of the battery housing case 1.

[0016]

EXAMPLE As for the assembled battery of the present invention shown in FIG. 1 and the conventional assembled battery shown in FIG. 5, the unit cells 3 as shown in FIG. The residual stress was measured for the four cells at the same position among the single cells 3 which were heated by the electric wire 11 (provided with the heating wire 8 in FIG. 3) and the electric heater 11. The method will be described in detail below.

Among the single cells 3 housed in the battery housing case 1, the four cells arranged at the four corners have residual stress on the inner surface of the solid electrolyte tube 12 at regular intervals in the height direction. Five strain gauges 23 for measurement were attached. Next, the assembled battery of the present invention shown in FIG. 1 and the conventional assembled battery shown in FIG. 5 were heated by the heating device 7 and the electric heater 11, respectively, and the residual stress at the time when the temperature was raised to 350 ° C. was measured. . The results are shown in Table 1. The measurement points were 1, 2, 3, 4, 5 from the bottom of the battery to the top.

[0018]

[Table 1]

From Table 1, it can be seen that the residual stress variation is large in the conventional assembled battery, but is significantly improved in the assembled battery of the present invention.

As the electrically insulating plate material used in the present invention, inorganic fiber bodies such as rock wool, glass wool and silica wool, or those obtained by adding inorganic powder such as quartz powder to form a plate-like inorganic binder. A molded product can be used. As the heating wire, an ordinary nichrome wire or band can be used as it is, or a wire covered with a glass fiber sleeve can be used. In the latter one, even if the arrangement of heating wires is dense,
Since a short circuit does not occur, there is an advantage that the temperature distribution can be made more uniform.

[0021]

From the above results, the sodium of the present invention
The heating device for an assembled battery composed of a sulfur battery has a moderate temperature distribution gradient on the surface of the heating device, and can uniformly and gradually heat the cells stored in the battery storage case from their side surfaces. Therefore, generation of thermal stress can be mitigated, and it can contribute to the improvement of safety of the assembled battery composed of sodium-sulfur battery. Also, since the heating device is integrated, it is possible to configure the assembled battery. It can be easily attached and detached.

Further, by disposing a plurality of independent heating wires in parallel in the heating device, the heating power can be adjusted by selecting the number of heating wires and one heating wire is disconnected. However, it is possible to heat with another heating wire, and it is not necessary to stop the operation of the assembled battery to cool it for repair.

[Brief description of drawings]

FIG. 1 is a schematic view in which an assembled battery including a sodium-sulfur battery according to an embodiment of the present invention is partially cut away.

FIG. 2 is a plan view showing a state in which a heating device is installed in the assembled battery of the present invention.

FIG. 3 is a plan view of an example of a heating device in the assembled battery of the present invention from which an electrically insulating plate material on one surface is removed.

FIG. 4 is a plan view of another example of the heating device in the assembled battery of the present invention, in which the electrically insulating plate material on one surface is removed.

FIG. 5 is a schematic view in which a conventional assembled battery is partially removed.

FIG. 6 is a vertical cross-sectional view of a single cell of a sodium-sulfur battery that constitutes the assembled battery.

[Explanation of symbols]

1 Battery storage case 2 lid 3 cells 5 parallel connection wires 6 insulated container 7 heating device 8 heating wire 9 Electrically insulating board 10 Electrically insulating board 11 Electric heater 12 Solid electrolyte tube 22 Battery case 23 Strain gauge It is not necessary to stop the operation of the assembled battery to cool it.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Eiichi Nomura             2-32 Kosobe-cho, Takatsuki City, Osaka Prefecture Stock             Ceremony company Yuasa Corporation F term (reference) 5H029 AK05 AL13 AM09 AM15 BJ02                       BJ06 BJ22 CJ30 DJ14 HJ12                 5H031 AA05 AA09 BB04 CC01 KK01                       KK03

Claims (2)

[Claims] 1. An assembly comprising sodium-sulfur batteries, characterized in that a plate-shaped heating device in which electrically insulating plate materials are arranged and integrated on both sides of a heating wire is installed on a peripheral wall surface of a battery housing case. Battery heating device. 2. A heating device for an assembled battery comprising a sodium-sulfur battery according to claim 1, wherein a plurality of independent heating wires are arranged substantially in parallel.