JPH08185900A - Temperature differential secondary battery - Google Patents

Abstract

PURPOSE: To provide a temperature differential secondary battery, allowing an easy operation and saving space. CONSTITUTION: An ion exchange membrane 3 is laid in the electrolyte for a temperature differential cell capable of generating an electro motive force, with one side of an electrode 2 set at high temperature and another side of an electrode 1 at low temperature to cause a temperature difference to appear across the electrodes 2 and 1. The concentration of electrolytes 6 and 7 separated from each other via the membrane 3 and existing at both sides thereof is thereby kept in a controllable state, depending on electrochemical reaction for providing a secondary system. In addition, auxiliary electrodes 8 and 9 are laid at both sides of the membrane 3 as a pair for use even during a charging process via the main electrodes 2 and 1. Also, the cell is made connectable in a cassette form. As a result, a battery set easy to operate as well as having a stable and sturdy structure can be provided, and heat is stably supplied. In addition, space can also be saved, and the battery set made of time differential secondary batteries can be provided, so as to give high energy density and have inexpensive constitution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature difference secondary battery which can be charged and discharged and can obtain a large capacity even when the temperature difference is eliminated.

[0002]

2. Description of the Related Art In recent years, effective use of energy has been emphasized,
Various types of recycling are popular. Effective use of energy has been emphasized not only in terms of cost but also from the viewpoint of global environment. In various heat engines, more than half of the energy is wasted as waste heat, and the recycling of this energy has been an urgent issue for research and development.

Conventionally, an electrochemical temperature difference battery has been known as one of thermoelectric conversion devices for converting heat energy into electric energy. An electrochemical temperature difference battery (hereinafter referred to as a temperature difference battery) provides a temperature difference between electrodes by raising the temperature of one electrode side and lowering the temperature of the other electrode side, and this temperature difference causes a difference in electrode potential. The voltage is generated by utilizing the phenomenon. Furthermore, in order to make the use of energy convenient, a proposal has been made that another pair of electrodes is provided on the temperature difference battery to make it secondary, and that the battery can always be used (Japanese Patent Application No. 4-28328).

FIG. 1 shows an example of the configuration concept of the proposed temperature difference secondary battery. In FIG. 1, 1 is a low temperature side electrode, 2 is a high temperature side electrode, and 3 is an ion exchange membrane. Reference numeral 4 is a cold / warm medium for fostering a low temperature environment, 5 is a high temperature medium for fostering a high temperature environment, 6 is an electrolytic solution on the low temperature side, and 7 is an electrolytic solution on the high temperature side. The high temperature medium 4 may be a heater. Depending on the medium of the cold medium 4 and the medium of the high temperature 5, the electrodes 1, 2
When a temperature difference occurs between them, a voltage is generated between the electrodes 1 and 2. When the circuit 10 is formed by an external conductor,
A flow of electrons occurs (in the case of FIG. 1, the low temperature side is oxidized and the high temperature side is reduced, that is, the high temperature side is the positive electrode and the low temperature side is the negative electrode), and accordingly, the concentration difference between the electrolytic solutions 6 and 7 occurs. Will occur. The ion exchange membrane has a function of controlling the counter ion of the generated concentration difference. If the auxiliary electrodes 8 and 9 are installed on both sides of the ion exchange membrane and the external circuit 11 is formed in this battery, current can be obtained. That is, the auxiliary electrodes 8 and 9 generate an effective current by eliminating the concentration difference between the electrolytes 6 and 7 caused by the electrodes 1 and 2 under the temperature difference setting. If this external circuit is opened, the concentration difference between the electrolytic solutions 6 and 7 is enlarged by the temperature difference setting electrodes 1 and 2, and this corresponds to charging in a general secondary battery. In the present specification (including the claims), the expansion of the concentration difference between the electrolytic solutions due to the main electrode of the temperature difference secondary battery under the temperature difference setting will be referred to as charging.

The temperature difference secondary battery provided with the auxiliary electrodes 8 and 9 uses electric energy by the auxiliary electrodes 8 and 9 while performing charging by closing an external charging circuit that connects the main electrodes 1 and 2. Then, by maintaining the current balance of charging and discharging, ideally, the electric energy of the temperature difference battery can be continuously and permanently used as long as the temperature difference setting is continued.

As shown by the concept of FIG. 1, the temperature difference secondary battery can store electric energy in the battery without the need for a special charger, and the presence of the auxiliary electrode allows the battery to be charged even during charging in the main electrode. It is possible to operate. Moreover, the great feature was emphasized that the electric energy can be continuously acquired forever by appropriately maintaining the current balance between the two pairs of electrodes.

The temperature-difference secondary battery converts thermal energy with a limited utilization range into electric energy with a wider utilization range. For example, the temperature-difference secondary battery currently attracts attention from the viewpoint of effective energy utilization. It may be used by incorporating it into a generation system. In this case, the source of primary electric energy is a phosphoric acid fuel cell (PAFC) or a molten salt fuel cell (MCFC), or a new polymer exchange membrane fuel cell (PMFC) or solid oxide fuel cell (SOFC). Or a jet turbine engine or the like.

The cogeneration system is premised on constant operation, and the energy balance of the entire system is strictly maintained for operation. However, in the event of a sudden shutdown, assisting individual maintenance devices so as not to significantly disrupt their energy balance during that shutdown period, and replacing that electrical energy, lead acid batteries and conventional It was another jet turbine engine, and when these facilities were attached, it had the drawback of occupying an extra floor space. If this alternative is performed by the temperature difference secondary battery, the battery is mounted around the pipe of circulating hot water, so that the occupation of the extra floor area is small and normally the electric energy is supplied. Therefore, its effective value is significantly increased.

[0009]

However, pointing out the drawback of this temperature difference secondary battery, the electromotive force of the battery caused by the temperature difference exceeds 5 mV / ° C. even if all possible battery reaction active materials are taken into consideration. This is extremely small compared to general batteries. For example, in the case of a redox system of potassium ferrocyanide / potassium ferricyanide, the theoretical value is at most 14 at a temperature difference of 100 ° C.
The voltage remained low at about 0 mV.

Further, when the temperature differential battery is required to be used in the above-mentioned cogeneration system or the like, auxiliary devices such as an electrolytic solution circulating device necessary for operating the battery are eliminated as much as possible, and space saving is thoroughly implemented. Assembling requires only a small number of parts, is easy to perform, and costs are low.

However, at present, since the ion exchange membrane and the auxiliary electrode are added for the purpose of making the temperature difference battery secondary, parts for sealing the exchange membrane, parts for installing the auxiliary electrode and wiring, etc.
On the contrary, the battery structure became extremely complicated. For this reason, the volume of the battery is inevitably larger than that in the case of the primary battery, and the cost is increased. further,
When the need for complicated wiring accompanying the installation of auxiliary electrodes is satisfied, not only is the battery volume increased, but there is concern that the sealing performance will deteriorate, and it is extremely difficult to form an assembled battery by combining cells as is. It was a technically difficult task.

[0012]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a temperature difference secondary battery which is simple and saves space in order to improve the above-mentioned current situation.

[0013]

In order to achieve such an object, the temperature difference secondary battery according to the present invention is started by setting one of the electrodes at a high temperature and the other of the electrodes at a low temperature and providing a temperature difference between the electrodes. Ion-exchange membrane was introduced into the electrolyte of the temperature difference battery that generates electric power, and the concentration of the electrolyte on both sides separated by the ion-exchange membrane was converted to secondary according to the electrochemical reaction. Further, the present invention is characterized in that a pair of auxiliary electrodes are provided on both sides of the ion exchange membrane so that a single battery of a temperature difference secondary battery that can be used even during charging by the main electrode can be connected in a cassette type.

The present invention proposes to construct a unit cell of a temperature difference secondary battery so that the unit cells can be simply connected and arranged in a cassette type.

That is, the shape of the unit cell of the temperature difference secondary battery is such that a concave portion is provided on one side surface of the unit cell and a convex portion is provided on the other side surface thereof, and the positive terminals of the main electrode and the sub electrode are provided on one side. The negative terminal is arranged on the other side surface so that each electrode has a constant height.

The present invention will be described in more detail with reference to the drawings.

FIG. 2 is an overhead view cross-sectional view showing one basic structural concept of the unit cell for satisfying the new battery construction method for the temperature difference secondary battery according to the present invention. In FIG. 2, plastic sheets 12 and 13 having hollow parts are arranged on both sides of the ion exchange membrane 3 in order to block the mixing of the electrolytic solutions 6 and 7 on both sides. Auxiliary electrodes 8 and 9 are arranged on the outer sides of both sheets, and current collectors 14 and 15 are arranged in contact with each other. Spaces 6 and 7 between the current collectors 14 and 15 and the main electrodes 1 and 2 that fill the electrolytic solution are secured by installing spacers 16 and 17. Each of the current collectors 14 and 15 has a lead plate at the same height in left and right directions.

These battery components include a battery case 22 having a heat conduction plate 18 and a lead plate 20 extending therefrom.
Similarly, a heat conduction plate 19 and a lead plate 21 extending from this
It is sandwiched between the battery case 23 and the battery case 23, and the joint surfaces of the battery cases 22 and 23 are joined together with an adhesive.

FIG. 3 is a diagram showing the constituent blocks of the unit cell having such a structure in an easy-to-understand manner.

A thin tube 2 is provided above the battery cases 22 and 23.
5 and 26 are attached, and the electrolyte spaces 6 and 7 in FIG. 2 are filled with the electrolyte from the capillaries.

FIG. 4 shows the appearance of the completed temperature difference cell. On both sides of the battery case, wedge-shaped protrusions A and recesses B having a corresponding shape that mesh with the wedge-shaped protrusions A are provided, and by utilizing this, the unit cells are combined in series.

The protrusions A and the recesses B are formed by bending the plus, minus, and lead terminals of the auxiliary electrode current collectors 14 and 15, and the case side surfaces other than the protrusions A and the recesses B have the same height. The lead plate 20 or 21 for the main electrode is present so that Therefore, by engaging two or more of the unit cells with the protrusions A and the recesses B engaged with each other,
Each of the auxiliary electrode and the main electrode is electrically connected.

The thin tubes 24 and 25 attached to the battery cases 22 and 23 are withdrawn after the necessary amount of electrolyte has been filled, and then the holes are filled with an adhesive or the like. When it is recognized that the drawing of the thin tube is inappropriate due to its structure, the thin tube can be closed by heat fusion or pinching while leaving the thin tube.

FIG. 5 shows a conceptual diagram when such cells are arranged in series. The cells can be connected in series using the protrusions A and the recesses B on both sides, and the lead cells 14 and 15 serving as the positive and negative terminals of the main electrode and the auxiliary electrode can be connected from the connected cells at both ends. 20, 2
There is one. If necessary, a terminal block 31 having lead terminals 26 and 28 and a recess 30 and a terminal block 33 having lead terminals 27 and 29 and a protrusion 32 are provided at both ends of the battery. The terminal can be easily connected by connecting to.

As the materials constituting the temperature difference secondary battery in the present invention, conventionally used materials can be used. An example is as follows.

That is, the main electrodes 1 and 2 can be selected from a platinum plate, plastic carbon composed of carbon and a plastic binder, carbon fiber and its woven cloth, graphite plate, etc., and the auxiliary electrodes 8 and 9 are electrolyzed. It can be selected from platinum mesh, carbon fiber woven cloth, etc. that do not prevent the movement of ions in the liquid.

The ion exchange membrane 3 is a styrene / divinylbenzene copolymer type polymer electrolyte, a styrene / butadiene / styrene / triblock copolymer type polymer electrolyte membrane, a polymer electrolyte membrane using Nafion, and the like. It can be selected in consideration of the ion species to be transmitted.

The plastic sheets 12 and 13 sandwiching the ion exchange membrane from both sides are polymer sheets satisfying excellent shielding property for shielding the mixture of the electrolytic solution on both sides of the ion exchange membrane 3, such as silicone rubber or polyethylene. , Polypropylene, polyvinyl chloride, polyvinylidene chloride, etc. The spacers 16 and 17 are non-conductive materials that satisfy the reliability of securing a space for the electrolytic solution and are non-conductive, and can be selected from polypropylene, polyethylene, Teflon, polyvinyl chloride and the like.

The current collectors 14 and 15 may be made of any conductive material that does not chemically or electrochemically react with the electrolytic solution. Specifically, a nickel plate, a titanium plate, a copper plate or the like may be used depending on the reaction system. Can be selected. Heat conduction board 18, 1
9 and the lead plates 20 and 21 can be selected from the same viewpoint.

The heat conduction plates 18 and 1 used in this example.
Reference numeral 9 is a flat plate that is supposed to be used in contact with an external low-temperature or high-temperature heat medium, but various shapes can be changed according to the necessity and use conditions.

The materials of the battery cases 22 and 23 are relatively excellent in heat insulating property so that they are not deformed in the application temperature range of the temperature difference secondary battery. , Polypropylene, polyethylene, Teflon, etc. can be used.

The electrolytic solution determines the reaction system of the temperature difference battery, and may be potassium ferrocyanide / potassium ferricyanide or the like.

The adhesive for uniting the battery cases 22 and 23 can be selected in consideration of the application temperature range of the temperature difference battery, but it is usually selected from commercially available epoxy adhesives and the like.

The structure of the temperature difference secondary batteries shown in these figures is a case where they are connected in series in a row, but in consideration of the application conditions, the projections A or the recesses B on both sides of the unit cell are taken into consideration.
A battery case for arranging either one of them in the lower part or the upper part is separately prepared, and either of the terminal lead plates of the collectors 14 or 15 of the auxiliary electrodes is arranged in the lower part or the upper part accordingly. Alternatively, the lead plate 20 or 21 extending from the heat conduction plate 18 or 19 may be manufactured by changing the position of the upper part or the lower part.

By using such a battery structure,
Even when the ion-exchange membrane and the auxiliary electrode are introduced to make them secondary, according to the configuration method of the present invention, a complicated auxiliary electrode circuit can be simplified and a simple and reliable assembled battery can be constructed. It will be possible.

Examples of the present invention will be described in detail below, but the present invention is not limited to these examples.

[0037]

EXAMPLE A 0.4 M potassium ferricyanide / 0.4 M potassium ferrocyanide mixed aqueous solution was used as an electrolytic solution, and a carbon fiber woven cloth was cut into a predetermined shape to form a main electrode and an auxiliary electrode. A styrene / divinylbenzene-based Neoceptor CM-1 (manufactured by Tokuyama Soda) was used for the cation exchange membrane to prepare a temperature difference secondary battery.

The test cell in this example is shown in FIGS.
The structure shown in FIG. Cation exchange membrane CM- in Figure 2
Silicon rubber sheets were used for the sheets 12 and 13 arranged on both sides of the sheet 1. As the current collectors 14 and 15, titanium nets were cut out and used. Teflon was used for the spacers 16 and 17. A SUS plate was used for the heat conduction plates 18 and 19, and nickel-made 20 and 21 were connected thereto by spot welding. The unit cell cases 22 and 23 were made of polypropylene, and the needle of the microsyringe was previously installed on the upper part of the case with an adhesive and used for filling the electrolytic solution. The Teflon cell case was glued with epoxy. The size of the unit cell was 5 cm in width and 2 cm in depth. (Protrusion is 5 mm) Electrode is 3 cm x
It was 3 cm. Three unit cells thus produced were connected in series to form an assembled battery. The total length of the battery pack is 1
The height is 4 cm, the height is 5 cm, which is the same as that of the unit cell, and the depth is 2 cm, which is the same as the unit cell.
It became cc.

For comparison, three unit cells of the same size as the battery of the embodiment of the present invention, in which the main electrode and the auxiliary electrode plus and minus terminals are formed on the upper part of the unit cell, are manufactured, and the terminals are crocodile clips. Were connected and connected to form an assembled battery. In this case, the total length of the battery pack is 15 cm, the height is 7 cm including the wiring space of 2 cm, and the depth is 2 cm, which is the same as that of the unit cell, and the total outer volume calculated as a rectangular parallelepiped is 210 cc, which is the same size. Although it was a single cell, the occupied volume was 1.5 times that of the construction method of the present invention, and the waste of occupied space was large.

An iron plate having a width of 10 cm, a length of 20 cm, and a thickness of 2 cm, in which a pipe having an inner diameter of 8 mm was incorporated, was prepared as a heat source, and the plate was placed in contact with the heat conduction plates on both sides of the assembled battery.
Oil was circulated from the oil bath to one iron plate to set the high temperature side electrode to 70 ° C, and cooled iron was circulated to the other iron plate to set the low temperature side electrode to 50 ° C.

In the case of comparison, it was necessary to clamp and fix the battery in contact with the iron plate with a vise in order that each unit cell could easily move due to a slight external factor to supply stable heat.
In the case of the assembled battery of the present invention, this is not necessary, and the iron plate that is well fixed by the connection of the irregularities on both sides of the unit cell can be easily contacted.

When the variation of the temperature difference was measured for the assembled battery of the constitution method of the present invention for one hour, the deviation from the average value of the temperature difference was not different among the individual cells, and both stopped at ± 3 ° C. On the other hand, in the assembled battery of the configuration of the comparative example, the variation in the temperature difference is different depending on each unit cell before the strong clamping with the vise, and the central unit cell is ± 3 ° C., which is the same as the assembled battery of the present invention. However, the cell size at both ends was as large as ± 5 ° C and ± 7 ° C, respectively. By tightening firmly with a vise, this variation was reduced and it was improved to ± 3 ° C and ± 4 ° C at both left and right ends.

According to this, in the present embodiment, the assembled battery of the construction method according to the present invention occupies less space than the assembled battery of the comparative example having the conventional construction, and the heat supply is stable and robust. It became clear that it could be done stably.

[0044]

As described above, the temperature-difference secondary cell according to the present invention makes it possible to produce a simple and stable and robust assembled battery, stably supply heat, save space, and realize high energy density. An assembled battery of a temperature difference secondary battery having an inexpensive structure has become possible.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a configuration concept of a temperature difference secondary battery.

FIG. 2 is an overhead view of one structural concept of the temperature difference secondary battery according to the present invention.

FIG. 3 is a block configuration diagram based on one configuration concept in the present invention.

FIG. 4 is an external view of a temperature difference single cell manufactured according to one configuration concept of the present invention.

FIG. 5 is a conceptual diagram showing a configuration of temperature difference secondary batteries connected in series in the present invention.

[Explanation of symbols]

 1 Low temperature side main electrode of temperature difference secondary battery 2 High temperature side main electrode of temperature difference secondary battery 3 Ion exchange membrane 4 Low temperature medium 5 High temperature medium 6 Low temperature side electrolyte solution 7 High temperature side electrolyte solution 8 Temperature difference secondary battery Auxiliary electrode installed on the low temperature side of the battery 9 Auxiliary electrode installed on the high temperature side of the temperature difference secondary battery 10 External circuit for charging the temperature difference of the main electrode 11 Discharge external circuit of the auxiliary electrode 12 Ion exchange membrane pressure bonding sheet 13 Ions Exchange membrane pressure-bonding sheet 14 Current collector for auxiliary electrode 15 Current collector for auxiliary electrode 16 Spacer 17 Spacer 18 Heat conduction board 19 Heat conduction board 20 Lead plate for main electrode 21 Lead plate for main electrode 22 Battery case 23 Battery case 24 Electrolysis Liquid filling thin tube 25 Electrolyte filling thin tube 26 Auxiliary electrode lead terminal 27 Auxiliary electrode lead terminal 28 Main electrode lead terminal 29 Main electrode lead terminal 30 Cavity 31 Terminal block 32 projection 33 Terminal Block

Claims (3)

[Claims] 1. An ion exchange membrane is introduced into an electrolytic solution of a temperature difference battery in which one of the electrodes is set to a high temperature and the other of the electrodes is set to a low temperature, and a temperature difference is provided between the electrodes to generate an electromotive force. Then, the concentration of the electrolytic solution on both sides separated by the ion exchange membrane is controlled so as to be controlled according to the electrochemical reaction, and a pair of auxiliary electrodes are provided on both sides of this ion exchange membrane to form the main electrode. A temperature-difference rechargeable battery characterized in that a single battery of a temperature-difference rechargeable battery that can be used even during charging by means of a cassette type can be connected. 2. A protrusion is provided on one side of the unit cell and a recess is formed on the other side for fitting the protrusion, and a lead terminal of an auxiliary electrode current collector is provided on the protrusion or the recess. A lead plate for the main electrode is provided on the case side surface of the unit cell so as to have the same height, and the auxiliary electrodes and the main electrodes are fitted to the protrusions and recesses of two or more unit cells. The temperature-difference secondary battery according to claim 1, wherein the temperature-difference secondary battery is electrically connected to the secondary battery. 3. The temperature difference secondary battery according to claim 1, wherein two or more unit cells are connected in a cassette type.