JPH0364870A - Electrolyte circulation type metal-halogen battery - Google Patents

Abstract

PURPOSE:To prevent generation of an intercell microcurrent at the shelf time of a battery by simple constitution by inserting a hollow cylindrical cock into a manifold of a battery stack while automatically performing breaking control corresponding to the working/nonworking time of the battery by the action of reinforced force of a cock spring and liquid pressure of an electrolyte. CONSTITUTION:A hollow cylindrical cock 70 being free-slidably supported by respective manifolds while having a through-connecting hole 70b through- connecting the manifolds 53 and a channel 50b and a breaking part 70c breaking throughconnection and a cock spring 72 reinforcing the cock 70 to a breaking state are provided. That is that in the hollow cylindrical cock 70, its respective throughconnection parts 70b are moved by liquid pressure of an electrolyte during the electrolyte circulation time opposing to reinforced force of the cock spring 72 so as to oppose respective channels 50b. At the non-working time of a cell, on the other hand, that is, when the electrolyte passes to a non- circulation state, the respective breaking parts 70c are put back to the positions opposing to the respective channels 50b by the reinforced force of the cock spring 72 for being maintained. At the non-working time of the cell, conductivity in the intercell channels each other can be surely prevented thereby.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a metal-halogen battery with electrolyte circulation, and particularly to a structure for preventing the occurrence of leakage current during a period when the battery is left unused.

[Prior art] Metal-halogen batteries have been developed in which bromine, which has high solubility in electrolytes and excellent electrode reaction characteristics, is used as the positive electrode active material and metals such as zinc are used as the negative electrode active material, and are easy to store and handle. Due to its many advantages, such as high performance and high energy density, it is attracting attention as a driving source for electric vehicles, for example.

FIG. 5 shows the principle structure of a general metal-halogen battery disclosed in Japanese Patent Application Laid-Open No. 57-199167.

Zinc is used as the metal on the negative electrode side in the illustrated example,
An electrochemical reaction expressed by the following formula is performed via an electrolytic solution 18 between a positive electrode side reaction tank 14 and a negative electrode side reaction tank 16 in which the positive electrode 10 and the negative electrode 12 are disposed, respectively.

(Positive electrode) 2Br″″;: Br2+2e 2+ (Negative electrode) Zn +2e−;: Zn −(1
) Charging (overall) Zn''+2Br-,:!Zn 10Br2 Discharging In such a metal-halogen battery, an aqueous solution of zinc bromide ZnBr2 is used as the electrolyte 18, and if necessary, a conductivity improver, Bromine complexing agents, dendrite inhibitors, etc. are added.

During charging, the charging reaction shown by - in the first equation is carried out in reaction t1114.16, and on the positive electrode 10 side, bromine B r
On the other hand, on the negative electrode 12 side, zinc Zn is precipitated and a deposited layer of zinc is formed on the negative electrode 12.

Further, during discharging, a reaction opposite to that during charging is performed, which is indicated by -, and on the positive electrode 10 side, bromine B r 2 is reduced and becomes bromine ions B'', which are dissolved in the electrolytic solution 18, and on the negative electrode 12 side, zinc The deposited layer is oxidized to become zinc ions zn2+ and dissolved in the electrolytic solution 18.

The interiors of the reaction vessels 14 and 16 in which such electrical reactions occur are separated by separator membranes 20 to prevent self-discharge caused by bromine B r 2 generated during charging.

In order to prevent self-discharge, this separator film 20 allows various ions in the electrolytic solution 18 to pass through, but blocks the penetration of bromine B r 2 dissolved therein. An ion exchange membrane or a porous membrane is generally used as the separator membrane 20, but a porous membrane is desirable from the viewpoint of reducing the internal resistance of the battery.

The electrolyte circulation type battery includes a positive electrolyte storage tank 22 and a negative electrolyte storage tank 24 for storing energy obtained through a chemical reaction during charging.

The positive electrode side electrolyte storage tank 22 forms an electrolyte circulation path with the positive electrode side reaction tank 14 via piping 26, 28, and the positive electrode side reaction tank 1 is
18 g of the positive electrode electrolyte reacted in the storage tank 22
Send it to storage h! The electrolytic solution 18a in 122 is supplied to the reaction tank 14.

Here, if a bromine complexing agent is added to the electrolytic solution 18, bromine B r 2 generated during charging is complexed and precipitated as a complex compound 32 insoluble in the electrolytic solution 18. The complex compound 32 is sequentially precipitated and stored in the bottom of the storage tank 22 as a complex storage section 34.

Further, a valve 3 is connected between the complex storage section 34 and the pipe 28.
A complex feed tube 38 having 6. This valve 36 is normally open, and the complex compound 32 precipitated in the complex storage section 34 is sent out toward the positive electrode side reaction tank 14 via the pipe 28.

Further, the negative electrode side electrolyte storage tank 24 similarly forms an electrolyte circulation path with the negative electrode side reaction tank 16 via piping 40, 42, and uses a pump 44 provided in the circulation path. Negative electrode side electrolyte 18 reacted in negative electrode side reaction tank 16
b is sent out to the storage tank 24, and new electrolytic solution 18b is supplied from the storage tank 24 to the reaction tank 16.

Thus, this metal-halogen battery has storage tank 22.
A sufficient amount of electrolyte 18 is stored in 24, and the stored electrolyte 18 is
When charging using
Electric power can be stored by storing a bromine complex compound in the complex storage section 32 and forming a deposited layer of zinc on the negative electrode 12.

FIG. 6 shows an exploded perspective view of a battery stack of a general metal-halogen battery formed using such a principle.

This battery stack consists of a large number of electrode frames 48 and separator frames 50 stacked alternately, and both ends of which are closed by end blocks 52 (only one is shown in the illustrated example).

Each electrode frame 48 has an electrode portion 48a forming a positive or negative electrode on its front and back surfaces, and the separator frame 5
One electrode part 48a of the electrode frame 48 located on both sides of the electrode frame 48 is configured to form a positive electrode, and the other electrode part 48a forms a negative electrode.

On the other hand, the separator frame 5o has a separator film 50
a is supported.

The space between one electrode section 48a and one side of the separator membrane 50a forms one reaction tank, and the space between the other side of the separator membrane 50a and the next electrode section 48a forms the other side. It forms a reaction tank, which constitutes a cell, which is the basic functional unit of a battery stack.

A supply side common manifold 53 and a discharge side common manifold 54 penetrate through all the cells including the end block 52 of this battery stack and communicate with the positive and negative side reaction tanks.
is formed.

Therefore, the electrolyte 18 supplied from each electrolyte storage tank is
A channel sob formed in each separator frame 50 passes through each supply side common manifold 53, and a current plate 50c is formed at the connection portion with the separator film 50a.
After being evenly introduced into each reaction tank and subjected to a predetermined chemical reaction, the discharge side supply manifold 5
4 and returns to the electrolyte storage tank again.

[Problems to be Solved by the Invention] However, in the conventional device as described above, each cell is electrically connected in series, whereas the electrolyte 18
The respective circulation paths are connected in parallel. Therefore, when the batteries are not in use, adjacent cells in the battery stack are electrically connected to each other via the electrolyte 18 remaining in the manifolds 53 and 54, causing a problem of leakage current.

One possible way to deal with this is to drain the electrolyte from the battery stack in advance when the battery is left unused.

However, with this method, the electrolyte storage tank must be enlarged to store the extracted electrolyte, which lowers the energy density and requires air bleeding from the reaction chamber when reusing the battery, making it difficult to start. The disadvantage is that it takes time.

Furthermore, Japanese Utility Model Application Publication No. 17068/1983 proposes a configuration in which a cock for shutting off the liquid junction between each cell is provided in the manifold or each channel, but the opening and closing of the cock must be controlled manually. , which requires a lot of effort.

Further, Japanese Utility Model Application Publication No. 63-43360 discloses a structure in which an electrolyte shutoff plug is provided in the middle of the channel and moves vertically depending on the liquid pressure.

However, even with this method, since the liquid junction is cut off when the liquid is not flowing by using its own weight, there is a problem that the operation is unstable, such as not functioning smoothly when the vehicle is tilted or the like.

The present invention has been made in view of the above-mentioned conventional problems,
The purpose is to provide a metal-halogen battery with electrolyte circulation that can reliably prevent shunt loss caused by minute currents generated between adjacent cells of a battery stack when the battery is left in a charged state with a simple configuration. It is in.

Means for Solving Problem C] In order to achieve the above object, the present invention provides a system that is slidably supported by each manifold, is formed alternately corresponding to each of the channels, and communicates between the manifold and the channels. A hollow cylindrical cock that has a communication hole and a blocking part that blocks communication, and a cock spring that is hung between an end of the hollow cylindrical cock and an end of a manifold and biases the cock to a blocked state. It is characterized by:

[Function] According to the present invention having the above configuration, the hollow cylindrical cock is attached to the cock spring so that each communication portion thereof faces each channel due to the liquid pressure of the electrolyte l& during the electrolyte flow period. When the battery moves against the force, and when the battery is not in use, that is, when the electrolyte is not flowing, the biasing force of the cock spring returns and holds the blocking portions in positions facing the channels.

As a result, when the battery is not in use, conduction between the channels between the cells is reliably prevented.

[Example] Preferred embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows an exploded perspective view of a battery stack in a circulating electrolyte metal-halogen battery according to the present invention. Components in the drawing that are equivalent to those of the conventional device shown in FIG.

A characteristic feature of the present invention is that a cock is provided in the manifold of the battery stack to automatically switch communication/cutoff between the separator channel and the manifold depending on the flow/non-flow of the electrolyte. It is possible to effectively prevent the generation of minute currents due to conduction between adjacent cells when the battery is left without any current flowing.

In FIG. 1, a hollow cylindrical cock 70 is pushed into a supply side common manifold 53 and a discharge side common manifold 54 of the battery stack.

FIG. 2 shows an external perspective view of the hollow cylindrical cock 70.

A cock spring 72 is locked to one end of the hollow cylindrical cock 70, and the other end of the cock spring 72 is locked to the terminal end of the end block 52 of the battery stack.

A plurality of sets of communicating holes 70b corresponding to the channels 50b of each separator frame 50 and blocking portions 70c are alternately formed below the main body 70a.

FIG. 3 shows a partial cross section of the stack in which the hollow cylindrical cock 70 having the structure described above is inserted into the common manifold 53 on the supply side. As mentioned above, the cock spring 72 is hooked between the terminal end of the manifold 53, 54, specifically, the inner wall of the end block 52 and the outer end surface of the cock 70, and the cock 70 is always moved toward the right in the figure. is energized.

At this time, as is clear from the figure, channel 50
b and the manifold 53 are cut off by a cutoff portion 70C, and the cells of the stack are not electrically connected to each other when the battery is not in use.

When the battery is put into use from this state and charging and discharging operations begin, the electrolyte circulates and the cock 70 is pushed to the left in the figure by the liquid pressure of the electrolyte flowing within the manifold 53.

As a result, the communication hole 70b of the cock 70 communicates with the channel 50b of the separator 50 of each cell, and the electrolytic solution flows into and out of the reaction tank to perform a predetermined charging/discharging reaction.

During the charging and discharging period, the electrolyte continues to flow through the battery circulation path in a full state without interruption, so the cock 70
is held in a depressed state toward the left in FIG. 3, so the arrangement of the cock 70 does not interfere with the charge/discharge reaction in any way.

Thereafter, when the use of the battery ends and the circulation of the electrolyte solution stops, the force of pushing the cock 70 to the left in FIG.
The biasing force returns the state shown in FIG. 3, and communication between each channel and the manifold 53 is cut off.

As a result, even if the battery is left in a charged state, the channels of each cell will not be electrically connected to each other due to a liquid junction.
This eliminates the inconvenience that the power accumulated while the battery is left unused is wasted.

By the way, in the above embodiment, the cock 70 is arranged in the supply side common manifold 53, but if it is arranged in the discharge side common manifold 54, the battery is left unused and then restarted. In this case, it is necessary to adopt a configuration in which the cock 70 moves to the left in the figure against the biasing force of the cock spring 72 due to the hydraulic pressure of the electrolyte flowing out from the channel 50b to the manifold 54.

For this reason, in the present invention, one of the shutoff portions 70C of the cock 70 is
A diagonal q-liquid tunnel 70d as shown in the figure is formed at the location, and the electrolyte that is about to flow upward through the channel 50c in FIG. The electrolytic solution is discharged, and the inside of the cock 70 is gradually filled with the electrolytic solution, increasing the liquid pressure, which pushes the cock 70 again to the left in the figure, so that the communication hole 70b and the channel 5ob are completely in communication with each other. be.

According to the present invention as described above, the hollow cylindrical cock 70 and the cock spring 72 are installed inside the manifolds 53 and 54 without changing the design of the battery stack itself.
By simply installing the battery, the fluid pressure is effectively used to automatically control conduction/cutoff between each cell in response to the flow/non-flow of the electrolyte, without affecting the original battery performance. It is possible to reliably prevent a liquid junction when the battery is left unused.

FIG. 4 shows a second embodiment of the present invention.

A characteristic feature of this embodiment is that, in order to improve the slidability of the cock 70 within the manifold 53° 54, the cock 70 is directly inserted into the manifold 53° 54 as in the first embodiment.
Rather than inserting a cock sleeve 80 into which the cock 70 is slidably fixed in advance, the cock sleeve 80 is arranged inside the manifolds 53 and 54.

In the illustrated example, a cock sleeve 80 is pushed and fixed from one end of the battery stack through the end block 52 and each cell from the left side of the figure.

A hollow cylindrical cock 70 similar to that of the first embodiment is slidably inserted into the interior of the cock sleeve 80, and the cock 70 is inserted between one end of the cock sleeve 80 and the end of the cock sleeve 80. The spring 72 is loaded.

In this embodiment, the lower surface of the cock sleeve 80 has a communication hole 80a that matches the width of each channel 50b.
is formed. Since the cock sleeve 80 is fixed within the manifold 53,54, this communication hole 80
The position of a remains unchanged.

As a result, in this embodiment, the channel 50b is extended upward by the communication hole 80a of the cock sleeve 80, and the communication/blocking action between the manifold 53, 54 and the channel 50b due to the hydraulic pressure described above is controlled by the cock 70 and the cock. This is done between the communication hole 80a of the sleeve 80.

According to this, the sliding movement of the cock 70 due to the hydraulic pressure and the biasing force of the cock spring 84 acts on the cock sleeve 80, so that a smoother communication/blocking effect can be obtained.

[Effects of the Invention] As explained above, according to the present invention, a hollow cylindrical cock is inserted into the manifold of the battery stack, and the cock spring is attached to the outer end surface of the cock and the terminal end of the manifold. The structure is configured so that conduction/cutoff control between each cell of the stack is automatically performed depending on whether the battery is in use or not, depending on the force and the liquid pressure of the electrolyte flowing in the manifold. It has an extremely simple configuration that eliminates the generation of minute currents due to liquid junctions between each cell when the battery is left unused, without the need for troublesome processes such as draining the electrolyte or changing the shape of the manifold or channel. This will effectively suppress the problem of unnecessary power consumption, which will definitely solve the problem.

[Brief explanation of drawings]

FIG. 1 is an exploded perspective view of a battery stack according to the present invention, FIG. 2 is an external perspective view of a hollow cylindrical cock according to the present invention, and FIG. 3 is a hollow cylindrical cock inside the manifold of the m-ground stack according to the present invention. FIG. 4 is a partial cross-sectional view of a battery stack showing a second embodiment of the present invention, FIG. 5 is a diagram showing the basic structure of a general metal-halogen battery, and FIG. FIG. 1 is an exploded perspective view of a conventional metal-oxide battery stack. 48 ... Electrode frame 48a ... Electrode part 50 ... Separator frame 50a ... 50b ... 53.54 70 ... 70b ... 70c ... 72c ... Separator membrane channel・・Manifold hollow cylindrical cock communication hole blocking part cock spring

Claims (1)

[Claims] A battery stack that constitutes a plurality of cells by alternately stacking a plurality of separator frames equipped with separator membranes and electrode frames forming electrode parts whose front and back surfaces form positive or negative electrodes. , an electrolyte storage tank connected to the stack via supply side piping and discharge side piping so as to circulate positive and negative side electrolytes through the stack, and the stack has a supply side that penetrates all the cells. A common manifold, a common discharge side manifold, and a supply side channel and a discharge side channel that respectively communicate with both the manifolds on both sides of each separator membrane are formed, and the respective manifolds and channels form a circulation path for the electrolyte in the stack. In the electrolyte circulating metal-halogen battery, communication holes are slidably supported on each of the manifolds and are alternately formed corresponding to each of the channels, communicating holes between the manifolds and the channels, and blocking portions that interrupt the communication. a cock spring that is hung between an end of the hollow cylindrical cock and a terminal end of the manifold and biases the hollow cylindrical cock to a shut-off state; During the electrolyte flow period, each communicating portion moves against the biasing force of the cock spring to face each channel due to the fluid pressure of the electrolyte, and when the electrolyte is not flowing, the cock spring is unbiased. An electrolyte circulating metal-halogen battery characterized in that each blocking portion is returned and held in a position facing each channel by a force, thereby preventing conduction between channels between cells when the battery is not in use.