JPH0131664B2 - - Google Patents

Description

[Detailed description of the invention] A: Industrial application field The present invention relates to the structure of a framed electrode used in electrolyte circulation type batteries such as metal (e.g. Zn)-halogen (e.g. Br) batteries and its manufacturing method. It is related to.

B: Summary of the Invention The first invention of the present application does not include a joint in the battery reaction chamber between an insulating frame that forms a battery reaction chamber on the electrode plate and the electrode plate, particularly an electrolyte passageway to the battery reaction chamber. A frame electrode is constructed by providing a concave groove on the insulating frame side at the joint between the opposing inner walls on both sides and the electrode plate surface.

A second invention of the present application provides that, in manufacturing the framed electrode according to the first invention, the electrode has a width larger than a dimension between inner walls of opposing sides of the side not provided with the flow path of the insulating frame, and A thin resin film made of a material that does not fuse with both the plate and the insulating frame is interposed between the electrode plate and the insulating frame, and after integrally molding the electrode plate and the insulating frame by heat compression, the resin is The thin film is removed to form a framed electrode having a groove on the insulating frame side at the junction between the inner wall of the insulating frame and the electrode plate surface.

C: Prior Art FIG. 1 is an explanatory diagram of the principle of an electrolyte circulation type battery. In the figure, electrodes 1 and 3 are arranged on both sides with a separator 5 in between to form a unit cell. In addition, in the case of FIG. 1, electrode 1 is a negative electrode, and electrode 3 is a positive electrode.

Then, the negative electrode liquid is supplied from the negative electrode liquid storage tank 6 to the battery reaction chamber (negative electrode chamber 2) between the electrode 1 (negative electrode) and the separator 5 and circulated, while the electrode 3 (positive electrode)
and the battery reaction chamber (positive electrode chamber 4) between the separator 5 and the separator 5.
The positive electrode liquid is supplied and circulated from the positive electrode liquid storage tank 7.

In addition, 9a and 9b are pumps for liquid circulation, 10a,
10b is a valve.

FIG. 2 is an exploded perspective view of a battery of the electrolyte circulation type constructed by stacking a large number of unit cells each composed of an electrode and a separator as shown in FIG.

In this figure, 11 is a clamping end plate made of aluminum, 12 is a resin clamping end plate, 13 is a gasket, 14 is an electrode end plate, and 15 is a terminal made of wire mesh or the like.

The battery is constructed by stacking electrodes 1 and separators 5 alternately, placing fastening end plates 11 on both sides in the stacking direction, and tightening the entire structure with bolts 16 and nuts 17.

This type of electrode 1 is integrally equipped with an insulating frame around the electrode plate, and the middle part in the thickness direction of the insulating frame is arranged so that battery reaction chambers (positive electrode chamber, negative electrode chamber) are formed on both sides of the electrode plate. An electrode plate is provided on the electrode plate to form a so-called frame electrode.

Further, this insulating frame is provided with a manifold 18 through which an electrolytic solution flows, and a flow path 20 through which an electrolytic solution flows between the manifold 18 and the battery reaction chamber. This flow path 20 is formed by a channel 19a and a microchannel 19b.

Incidentally, since the insulating frame of the electrode is required to have insulating properties and chemical resistance, this frame is formed of a polyolefin (for example, polyethylene)-based synthetic resin.

On the other hand, the electrode plate is made of a conductive resin (for example, carbon plastic) using a polyolefin (for example, polyethylene) type synthetic resin as a base polymer.

Then, to integrate the electrode plate and the insulating frame, frame members formed in the shape of a frame are placed on both sides of the rectangular electrode plate, and the two are overlapped and inserted into the mold.
Then, it is heated and compressed, thereby obtaining a framed electrode.

On the other hand, the electrolytic solution (for example, positive electrode solution) is applied to the clamping end plate 1
1. Flows through the manifold 18 that passes through the insulating frame of the electrode 1 and the frame of the separator 5 in the stacking direction, and in the channel 19a of the flow path 20 provided on one side of the frame of each electrode 1. The current is guided to each battery reaction chamber (positive electrode chamber), further rectified by a microchannel 19b on one side of the insulating frame, and then flows along the entire surface of the electrode plate.

This electrolytic solution that has flowed along the electrode plate in the battery reaction chamber of each electrode is transferred to other electrodes via a flow path (microchannel, channel, not shown) formed on the other side of the insulating frame of the electrode. The positive electrode liquid is guided through the manifold and refluxed to the positive electrode liquid storage tank (see reference numeral 7 in FIG. 1).

Note that the negative electrode liquid flows to the battery reaction chamber (negative electrode chamber) formed on the other side of the electrode plate of each electrode through a flow path route different from that of the positive electrode liquid. Since the structure of is similar to that of the positive electrode liquid, its explanation will be omitted.

D: Problem to be solved by the invention In the conventional framed electrode that integrates the electrode plate and the insulating frame as described above, the inner wall of the frame is in direct contact with the electrode plate, so the electrode plate and the insulating frame are in direct contact with each other. The flow of the electrolytic solution is not smooth at the boundary with the insulating frame, and the flow rate is significantly reduced compared to the maximum flow rate of the electrolytic solution inside the electrode chamber (positive electrode chamber, negative electrode chamber). For this reason, there is a problem in that bubbles are generated and remain in the vicinity of the frame, further worsening the flow.

E: Means for Solving the Problems The first invention of the present application includes a rectangular electrode plate, an insulating frame made of synthetic resin, and a pair of flow passages provided on one opposite side of the insulating frame. The insulating frame is provided around at least one surface of the electrode plate to form a battery reaction chamber surrounded by the insulating frame on the electrode plate surface, and the electrolyte is supplied to the battery reaction chamber from one of the flow paths. In the framed electrode configured to allow the electrolyte to flow in and flow out from the other side, a recess is formed on the insulating frame side at the joint between the opposing inner wall of the insulating frame and the electrode plate surface on the side of the insulating frame that does not have the flow path. It has grooves.

Further, in manufacturing the framed electrode according to the first invention, the second invention of the present application has a width dimension that is larger than the dimension between the inner walls of both opposing sides of the side that does not include the flow path of the insulating frame, In addition, a resin thin film made of a material that does not fuse with both the electrode plate and the insulating frame,
The electrode plate and the insulating frame are interposed between the electrode plate and the insulating frame, and after the electrode plate and the insulating frame are integrally molded by heating and compression, the resin thin film is removed to produce a framed electrode.

Note that the resin thin film is formed of, for example, Kapton, Teflon, or Mylar (all trademarks).

F: Function In the framed electrode of the present invention, since the groove is provided on the insulating frame side at the junction between the inner wall of the insulating frame and the electrode plate surface, the edge of the effective electrode surface of the electrode plate is inside the groove. It is possible to substantially define the range of the electrode surface according to the design value by the dimensions of the opening in the inner wall of the frame. Furthermore, since the edge of the effective electrode surface is formed by entering into the insulating frame, and the electrolyte also reaches the groove, disturbance of the current density at the peripheral edge of the interface between the electrode surface and the frame is also prevented. The grooves can be formed very easily by disposing a non-fusion thin film, press-molding it, and then peeling and removing the thin film.

G: Examples Next, the present invention will be described in detail based on examples shown in the drawings.

FIG. 3 shows the structural members necessary for manufacturing one framed electrode having battery reaction chambers on both sides of the electrode plate. Further, FIG. 4 shows the overlapping state of each member, and shows the side portion of the insulating frame that does not have a microchannel portion forming a flow path for the electrolytic solution.

In these figures, reference numeral 21 denotes an outer frame made of thermoplastic resin insulator, and a punching 22 is provided in the center of the frame through which an electrode plate 25 is exposed, and the frame is formed into a picture frame shape as a whole. There is.

Reference numeral 23 denotes an intermediate frame that forms a flow path (microchannel), and is made of the same material as the outer frame 21.

This inner frame 23 has the same outer shape as the outer frame 21, and has a punched-out 2 in which an electrode plate 25 is exposed in the center.
3a is provided, and the entire frame is formed into a frame shape similarly to the outer frame 21. However, the width d2 of the short side of the inner frame 23 is smaller than the width d1 of the short side of the outer frame 21.
It is increased in size by an amount corresponding to the portion forming the flow path 20.

24 is a resin thin film having a thickness of 0.3 mm or less. This resin thin film 24 is made of a material that does not fuse with the inner frame 23 and the electrode plate 25, and is made of, for example, a Kapton sheet, a Teflon sheet, a Mylar sheet, or the like.

Further, the short side dimension d3 of the resin thin film 24 is larger than the short side dimension d4 of the punched part 23a of the inner frame 23 by d5 on both sides.

Reference numeral 25 denotes an electrode plate made of carbon plastic, and its outer shape is almost the same as that of the outer frame 21.

Each member formed as described above is formed by placing the resin thin film 24, the inner frame 23, and the outer frame 21 on both sides of the electrode plate 25 in the order shown in FIG. The outer frame 21, the inner frame 23, and the electrode plate 25 are integrated by fusion molding by heat compression.

FIG. 5 is a sectional view of the portion of the insulating frame 26 that does not have a flow path, after the resin thin film 24 has been removed after being processed into the above-mentioned three-way fusion molding state. Note that the insulating frame 26 is formed by integrating the outer frame 21 and the inner frame 23 by fusion bonding.

As is clear from FIG. 5, at the joint between the insulating frame 26 and the electrode plate 25, the insulating frame 26 side is cut out by the amount where the resin thin film 24 was present, and the concave groove 27 is cut out.
is formed.

Furthermore, FIG. 6 shows a comparison of the current density with the conventional electrode, and compared to the conventional electrode shown in FIG. 6B, the electrode of the present invention shown in FIG. It can be seen that there is no local concentration of current density at .

Note that if one surface (the surface facing the electrode plate 25 side) of the resin thin film 24 described above is roughened by chemical or other treatment, that state will not change to the surface of the electrode plate 25. Since it is transferred, the surface of the electrode plate 25 can be made to have a desired surface roughness, thereby increasing the electrode surface area and further improving battery efficiency.

In addition, in the electrode manufacturing method in this embodiment, a resin thin film is interposed between the electrode plate and the insulating frame, and the resin thin film is integrally molded by heating and compression, and the resin thin film is removed after molding. Sometimes insulation frame 2
Even if a part of the material of 6 (inner frame 23, outer frame 21) melts and flows inside the punched part, since the thin resin film 24 exists on the electrode plate surface, an insulating coating will adhere to the surface of the electrode plate 25. By subsequently removing the resin thin film, the insulation frame 2 at the joint between the inner wall of the insulation frame 26 and the electrode plate 25 is completely removed.
At the same time as the concave groove 27 is formed on the 6 side, the excess flowing resin is peeled off.

H: Effect of the invention In the framed electrode according to the present invention, a groove is formed on the insulating frame side at the joint between the inner wall part and the electrode plate on the side of the insulating frame that does not have an electrolyte flow path to the battery reaction chamber. Since it is provided, there are various effects such as the following.

The electrolytic solution flows smoothly in the vicinity of the inner wall of the insulating frame where the groove is present, thereby making it possible to alleviate disturbance and local concentration of current density in the vicinity of the insulating frame.

As a result, the generation of dendrites (dendritic crystals of electrodeposited metal) in the vicinity of the insulating frame can be effectively suppressed, and as a result, battery efficiency can be significantly improved.

Since grooves are formed on the inner wall of the insulating frame,
Since the surface area of the electrode plate increases accordingly, battery efficiency can be improved.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the principle of an electrolyte circulation type battery, Fig. 2 is an exploded perspective view of a conventional electrolyte circulation type stacked battery in which a large number of unit cells are stacked, and Fig. 3 is a framed electrode according to the present invention. FIG. 4 is a cross-sectional view showing the overlapping state of each member in the part of the insulating frame that does not have an electrolyte flow path;
FIG. 5 is a sectional view showing the relationship between the insulating frame, the electrode plate, and the space in the finished product, and FIGS. 6A and 6B are explanatory diagrams of the current density on the electrode surface. 1 and 3 are electrodes, 2 is a negative electrode chamber (battery reaction chamber), 4
is the positive electrode chamber (battery reaction chamber), 19a is the channel,
19b is a microchannel, 20 is a distribution path, 2
1 is an outer frame, 23 is an inner frame, 24 is a resin thin film, 25 is an electrode plate, 26 is an insulating frame, and 27 is a groove.

Claims (1)

[Scope of Claims] 1. A rectangular electrode plate, an insulating frame made of synthetic resin, and a pair of flow passages provided on opposite sides of the insulating frame, and at least one surface of the electrode plate. The insulating frame is provided around the electrode plate to form a battery reaction chamber surrounded by the insulating frame on the electrode plate surface, and the electrolyte is allowed to flow into the battery reaction chamber from one side of the flow path and flow out from the other side. In the framed electrode configured as above, a concave groove is provided on the insulating frame side at a joint between the opposing inner wall of the insulating frame and the electrode plate surface on the side not provided with the flow path of the insulating frame. With electrode. 2. A rectangular electrode plate, an insulating frame made of synthetic resin, and a pair of flow passages provided on opposite sides of the insulating frame, and the insulating frame is arranged around at least one surface of the electrode plate. is provided to form a battery reaction chamber surrounded by an insulating frame on the electrode plate surface, and the frame is configured to allow the electrolyte to flow into the battery reaction chamber from one side of the flow path and to flow out from the other side. In the method for manufacturing an electrode, the resin is formed of a material that has a width larger than a dimension between opposing inner walls on the side of the insulating frame that does not include the flow path, and that does not fuse with both the electrode plate and the insulating frame. A thin film is interposed between the electrode plate and the insulating frame, and after the electrode plate and the insulating frame are integrally formed by heating and compressing, the resin thin film is removed and the inner wall of the insulating frame and the electrode plate surface are separated. A method for manufacturing a framed electrode, comprising forming a groove on the insulating frame side at a joint. 3. The method for manufacturing a framed electrode according to claim 2, wherein the surface of the resin thin film on the side in contact with the electrode plate surface is roughened in advance, and this rough surface shape is transferred to the electrode plate surface during molding. .