JPH03257766A - Module of sodium-sulfur battery - Google Patents

Abstract

PURPOSE:To realize safe and effective cooling with no sudden cooling, without reducing the energy density, by utilizing a holding structure means as a preheating passage of the cooling gas led in a cooling process, and as a distributer means to lead the cooling gas to the clearances between unit cells. CONSTITUTION:In a heat keeping container 1, numerous sodium-sulfur cells 6 are arranged thickly, and the air led in from an outer air leading port 3 enters in a hollow pipe 13 which is a part of a holding structure 9. And the hollow pipe 13 acts as a preheating passage to preheat the air by passing it though a specific distance. The heated air enters from apertures 12 to clearances 7 between unit cells 6, and touches and cools the unit cells 6, while the apertures 12 compose a distributor means to lead the air preheated in the hollow pipe 13 to the spaces between the unit cells 6. Consequently, an effective cooling with no sudden cooling can be realized without reducing the energy density.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a sodium-sulfur battery module, and particularly to a sodium-sulfur battery module that is suitable for gentle and effective cooling and has a simple cooling structure.

[Conventional technology]

The IJium sulfur battery is a secondary battery that uses molten sodium as the negative electrode active material, molten sulfur or sodium polysulfide as the positive electrode active material, and uses a solid electrolyte with sodium ion conductivity as the electrolyte. The battery is
It is characterized by a high energy density because the active material is lightweight, but in order to maintain the melting point of the active material,
It is necessary to maintain the temperature between 0 and 350°C.

A sodium sulfur cell is a basic component of a module battery, which will be described later, and typically has an output of several watts to several tens of watts. Further, the efficiency of discharging energy with respect to charging energy is 80 to 95%, and the loss is released as heat as Joule loss due to internal resistance. At the same time, the heat of the chemical reaction between sodium and sulfur is also released or absorbed, so the battery is always in an exothermic state during discharging, and is either exothermic or endothermic during charging, depending on the internal resistance. When at rest, it neither generates heat nor absorbs heat.

A sodium-sulfur battery module, that is, a module battery, has an output of several kilowatts to several tens of kilowatts, and is a constituent unit for electric vehicles or power storage plants. This output is achieved by connecting hundreds to tens of thousands of single cells in series and parallel, and the module battery consists of a structure that supports these single cells and their arrangement, and a structure that houses them and maintains operating temperature. It consists of a heat insulating container for heating.

Additionally, a device such as an electric heater is installed in the heat insulating container to supply the heat necessary to raise the temperature to the operating temperature.

In order to achieve high energy density, the unit cells must be densely arranged, and at the same time, the unit cells must be insulated except for the connections between the terminals at both poles. Therefore, the support structure needs to be strong enough to support the weight and maintain insulation between the cells, while at the same time ensuring space for installing the temperature increase heater, etc., and being lightweight. Must be.

Now, in order to maintain the operating temperature after the temperature has been raised, it is necessary to improve the insulation performance of the heat insulating container. The overall efficiency of a module battery is the overall efficiency of the module - the energy extracted by discharging / (the energy required for charging plus the energy required to maintain the temperature), so poor insulation performance will lead to a decrease in overall efficiency. .

When charging and discharging cycles are repeated at the vehicle level for a day, if the heat generated by the battery during charging and discharging is balanced by the heat loss over 24 hours,
On average, the operating temperature can be maintained. In this case, there is no need to supply heat externally, so the overall efficiency is equal to the efficiency of the battery. However, in practice, it is necessary to expect a long standby time, so it is normal to improve the insulation performance.

In this case, the heat generated from the battery exceeds the heat loss of the heat insulating container, so the battery temperature is rising.

Therefore, some type of cooling mechanism is required. More practically, since heat generation due to chemical reactions is added during discharge,
It is expected that the temperature of the battery will exceed the operating temperature range in the latter stages of discharge. It is necessary to provide a cooling mechanism that suppresses this.

A simple method for the cooling mechanism is to introduce outside air into the heat-insulating container. This conventional cooling mechanism is
There is a device described in Publication No. 1476, in which an outside air inlet is provided at the top of the unit cell group and an outlet is provided at the bottom to guide the outside air introduced into the heat insulating container around the unit cells. It is equipped with a distributor.

Furthermore, as described in Japanese Patent Application Laid-Open No. 59-103283, by arranging a cooling body having a cooling loop inside between the end battery arrays in a heat insulating container and passing outside air through the cooling loop, Some have a structure that exchanges heat with the high-temperature gas of the cell.

[Problem to be solved by the invention]

However, in the conventional device described in Japanese Patent Application Laid-Open No. 59-171476, the outside air introduced into the heat insulation container through the inlet flows directly into the distributor, and after passing through the distributor, it is forced to move from the top of the cell due to gravity. Since it quickly flows toward the bottom, there was a problem in that the battery cells were cooled down rapidly. When a cell is rapidly cooled,
Thermal stress can lead to damage.

In addition, in the conventional device described in JP-A-59-103283, the volume inside the heat-insulating container is increased by installing a cooling body to provide a cooling loop, and the ratio of energy that can be taken out per unit volume, that is, volumetric energy. There was a problem in that the density, or the proportion of energy that can be taken out per unit weight, that is, the gravimetric energy density decreased.

An object of the present invention is to provide a sodium-sulfur battery module that allows effective cooling without rapid cooling without reducing energy density.

[Means to solve the problem]

To achieve the above object, the present invention supports an array of a large number of sodium-sulfur cells connected in series and parallel, each having a pair of positive and negative terminals, and an arrangement of the large number of sodium-sulfur cells. , a support structure means constituting a battery main body, a heat insulating container for housing the battery main body and maintaining an operating temperature, and a cooling means for introducing cooling gas into the heat insulating container to cool the sodium sulfur cell. In the sodium-sulfur battery module, the cooling means is formed by a cooling gas inlet and an outlet provided in the heat insulating container and a part of the support structure means, and the cooling gas introduced from the inlet It has a preheating passage for preheating the gas by passing it a certain distance, and a number of openings provided in another part of the support structure means, and the cooling gas preheated in the preheating passage is passed through the plurality of sodium sulfur cells. and a distributor means for introducing the air into the gap between the two.

Preferably, the support structure means has a column made of at least one hollow member, and a hollow part of the column communicates with the inlet to form the preheating passage. It is preferable that this support made of a hollow member is located at the center of the cross section of the battery main body.

Further, the support structure means has at least one floor plate that supports the plurality of sodium sulfur cells, and the floor plate is spaced apart from the inner wall of the heat insulating container so that the inlet port faces between the inner wall and the inner wall. installed, a first portion of the floor plate closer to the inlet is non-perforated, a second portion farther from the inlet is formed with an opening for the distributor means, and the first portion of the floor plate is formed with an opening for the distributor means; The preheating passage may be formed between the inner wall and the inner wall.

[Effect]

In the present invention configured in this way, the cooling gas introduced from the introduction is first preheated in the preheating passage and then guided between the cells by the distributor means, so that effective cooling without rapid cooling can be achieved.

In addition, since the preheating passage and the distributor means are constructed by using a part of the support structure means of the unit cell, which is essential as a component of the module battery, there is no need to provide a special structure for the preheating passage or the distributor means, and the module No reduction in the volumetric or gravimetric energy density of the battery occurs.

Further, as described above, the support structure means must have strength to support the weight of the densely arranged unit cells and must also be lightweight. Therefore, by configuring at least one of the struts of the support structure means with a hollow member and configuring the preheating passage with this hollow member, the function of the preheating passage is provided to a part of the support structure means while maintaining the light weight and strength. It can also be used.

Effective cooling can be achieved by providing an opening in the part that is most desired to be cooled to form a distributor means and introducing the distributor into the surface of the unit cell.

When a cell generates heat, the temperature distribution of the battery body is maximum at the center of the cross section, but by placing the hollow member that introduces cooling gas and preheats it at the center of the cross section of the battery body, Because the center can be further cooled,
Effective cooling is possible.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 and 2.

In FIG. 1, the module 8 of the sodium-sulfur battery of this embodiment has a heat-insulating container 1, which is shaped like a rectangular parallelepiped box with one side open, and whose surface is closed with a lid 2 to form a hermetically sealed container. form a space. The lid 2 has an outside air inlet 3.
, discharge ports 4a, 4b.

There are penetration parts such as current terminals 5a and 5b and measurement wires (not shown). A large number of sodium-sulfur cells 6 are densely arranged in the heat-insulating container 1. The unit cells 6 have a cylindrical shape, and are densely arranged, with an axial inter-cell gap 7 between adjacent unit cells. A large number of unit cells 6 are connected in series and parallel (not shown) so as to obtain the output of the module battery 8, and finally the positive and negative electrodes are collected and connected to the current terminals 5a and 5b. The support structure 9 is a structure for supporting the arrangement of the single cells 6, and is electrically insulated from the single cells 6. Furthermore, an electric heater or the like (not shown) for raising the temperature is provided at an appropriate position in the internal space of the support structure 9.

The cell groups are arranged in two layers, upper and lower, and the support structure 9 also has a two-layer structure so that the upper and lower cell groups can be insulated. This support structure is provided with columns 10 at the four corners, which reach from the upper end to the floor and, together with a centrally placed hollow tube 13, constitute a longitudinal structural member. In the horizontal direction, there are double floor plates 11a and llb and an upper beam 14.
15 are connected to form a tower. double floorboard 11
A and Ilb each have a large number of openings 12 at the same positions as the inter-cell gaps 7, and serve as air flow paths. The inside of the hollow tube 13 and the gap between the double floor plates 11a and Ilb are connected, and the air that has passed through the hollow tube 13 is introduced into the gap between the floor plates 11a and Ilb, and then passes through the opening 12.
is introduced into the inter-cell gap 7 through the cell. The upper end of the hollow space 13 is connected to the outside air inlet 3, and the outside air is introduced into the outside air inlet [
After entering through the hole 3 and passing through the internal space as described above, it is discharged to the outside through the exhaust ports 4a and 4b.

Now, when the module battery 8 is in operation, the temperature of the unit cell 6 must be maintained at 300 to 350°C. The heat insulating container 1 and the lid 2 have sufficient heat insulation performance to reduce the amount of heat required to maintain the internal temperature even in a standby state. When energized, the cell 6 generates Joule heat due to its internal resistance, and especially during discharge, chemical reaction heat is also added, generating heat that exceeds the heat insulation properties of the heat insulating container. in this case,
The temperature of the unit cell 6 rises, and often deviates from the operating temperature range, especially in the latter stages of discharge. At this time, cooling must be performed. Cooling is performed by introducing outside air into the interior through the outside air introduction port 3.

Air introduced through the outside air inlet 3 enters a hollow tube 13 that is a part of the support structure 9. While passing through the hollow tube 13, the air receives and removes heat and is warmed. That is, the hollow tube 13 provides a preheating passage for preheating the air introduced from the outside air inlet 3 by passing it a certain distance. floorboard 11
The warmed air that has reached a and 1.1b is
It is introduced into the gap between 1a and Ilb, enters the intercell gap 7 through the opening 12, contacts the unit cell 6, and removes its heat, thereby cooling the unit cell 6. The opening 12 guides the air preheated by the hollow tube 13 between the cells 6 (constituting a distributor means. In the above process, the heat of the support structure 9 is also removed, so the temperature of the support structure itself decreases. do.

By making the hollow tube 13 of the support structure 9 function as a preheating passage and allowing the outside air to reach the outer surface of the cell, the initial temperature difference of about 300° C. between the outside air and the cell 6 is reduced, causing damage to the cell 6. Such rapid cooling never occurs. In addition, when the unit cells 6 generate heat, the temperature distribution of the unit cell group becomes maximum at the center, but as in this embodiment, a hollow tube 13 is provided at the center to introduce outside air and preheat it. If so, the central part can be further cooled, so that effective cooling is possible.

The cooling effect is adjusted by balancing the air volume and the heat capacity of the hollow tube 13.

As described above, according to this embodiment, by making a part of the support structure 9 hollow to serve as a preheating passage for outside air, safe and effective cooling becomes possible. In addition, since a part of the support structure 9 is used to constitute the preheating passage and the distributor means, no special structure is provided as the preheating passage or the distributor means, and the volumetric energy density or gravimetric energy density of the module battery is No decrease occurs.

Another embodiment of the present invention will be described with reference to FIGS. 3 and 4.

In FIGS. 3 and 4, the sodium-sulfur battery module of this embodiment has a structure in which a lid 2A is attached from the side, and an outside air inlet 3A is passed through near the lower end of the lid 2A. No hollow member is provided in the support structure 9A, and a gap 17 between the inner wall bottom surface 16 of the heat-insulating container IA and the floor plate 11 is used instead of the hollow tube 13 in FIG. 2. That is, the floor plate 11 is installed floating from the inner wall bottom surface 16 so that the outside air inlet 3A faces between it and the inner wall bottom surface 16 of the heat insulating container 1A.
The first portion 18 on the side closer to the outside air inlet 3A of the floorboard 11 is made non-porous, and the opening 12 as a distributor means is formed in the second portion 19 on the side farther from the outside air inlet 3A. Gap 17 between portion 18 and inner wall bottom 16
This forms a preheating passage.

The air introduced from the outside air inlet 3A is introduced into the gap 17, receives heat from the floor plate 11 and the inner wall bottom 16, and is warmed. After that, it passes through the opening 12 and enters the inter-cell gap 7, where it is heated. Contact the battery 6. After cooling the cell 6,
It is discharged to the outside from the exhaust port 4A. The side of the heat insulating container IA near the lid 2A is an area where heat radiation is relatively large due to the existence of the lid 2A, and the center of the temperature distribution is the second part 1 of the floorboard 11.
It is in the area of 9. For this reason, the first portion 18 of the floorboard 11
Preheating of the first part 18 also provides the necessary cooling of the cells 6 located on the first part 18, even if the first part 18 is non-porous.

As described above, in this embodiment, by raising the floor surface of the support structure, a hollow section is provided between the bottom surface 17 of the inner wall of the heat-insulating container IA, and outside air is introduced into the hollow section, which serves as a preheating passage. The idea is to achieve cooling.

In addition, in order to more effectively cool the center of the temperature distribution of the cell 6 on the second portion 19 of the floor plate 11, the size and position of the opening 12 are adjusted according to the position of the center. Good too.

〔Effect of the invention〕

According to the present invention, the support structure means for the unit cells, which is essential for a module battery, can be used as a preheating passage for the cooling gas introduced during cooling and as a distributor unit for guiding the cooling gas into the gaps between the unit cells. The effect is that safe and effective cooling without rapid cooling is possible without reducing energy density.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view of a module battery according to an embodiment of the present invention, FIG. 2 is a cross-sectional view showing only the support structure of the module battery of FIG. 1, and FIG. FIG. 3 is a vertical cross-sectional view of a module battery according to another embodiment of the invention;
FIG. 4 is a cross-sectional view showing only the supporting structure of the module battery shown in FIG. 3. Explanation of symbols 1...Thermal container 3.3A...Outside air inlet 4.4A...Outlet port 6...Single cell 7...Gap between cells 8.8A...Module battery (sodium Sulfur battery module) 9.9A... Support structure 11a, llb, 11... Floor plate 12... Opening (distributor means) 13...
Hollow tube (hollow member: preheating passage) 16...Inner wall bottom surface 17...Gap (preheating passage) 18...First part 19...Second part] Figure 19: Second part

Claims (4)

[Claims] (1) An array of a large number of sodium sulfur cells connected in series and parallel, each having a pair of positive and negative electrode terminals, and a support structure that supports the arrangement of the large number of sodium sulfur cells and constitutes a battery body. A module for a sodium-sulfur battery, comprising: a heat-insulating container for storing the battery body and maintaining an operating temperature; and a cooling means for introducing cooling gas into the heat-insulating container to cool the sodium-sulfur cell. , the cooling means is formed by a cooling gas inlet and an outlet provided in the heat insulating container and a part of the support structure means, and the cooling gas introduced from the inlet is passed through a certain distance for preheating. and a distributor means having a plurality of openings provided in another part of the support structure means for guiding the cooling gas preheated in the preheating passage to the gaps between the plurality of sodium sulfur cells. A sodium-sulfur battery module characterized by having: (2) In the sodium-sulfur battery module according to claim 1, the support structure means has a column made of at least one hollow member, and the hollow part of the column is communicated with the inlet, and the preheating passage is connected to the column. A module of a sodium-sulfur battery characterized by forming. (3) The sodium-sulfur battery module according to claim 2, wherein the support made of the hollow member is located at the center of the cross section of the battery body. (4) In the sodium-sulfur battery module according to claim 1, the support structure means has at least one floor plate for supporting the plurality of sodium-sulfur cells, and the floor plate is provided between the inner wall of the heat-insulating container and the support structure means. The distributor means is installed away from the inner wall so that the inlet faces the inlet, a first part of the floor plate on the side closer to the inlet is non-porous, and a second part farther from the inlet is provided with the distributor means. A module for a sodium-sulfur battery, characterized in that an opening is formed therein, and the preheating passage is formed between the first portion of the floor plate and the inner wall.