JPH0537426Y2 - - Google Patents

Description

[Detailed explanation of the idea]

A. Industrial Application Field This invention relates to the structure of a separator, which is a microporous membrane that separates a positive electrode electrolyte and a negative electrode electrolyte in a stack of zinc-bromine batteries. B. Summary of the invention The present invention is based on a separator that is a microporous membrane that separates a positive electrode electrolyte and a negative electrode electrolyte in a stack of zinc-bromine batteries. By integrally injection molding the frame plate with a band formed into a band shape and forming the separator plate, the boundary between the separator and the frame plate is reinforced, and the separator shrinks during use of the battery. This prevents the boundary portion from breaking. C. Prior Art Recently, the development of battery power storage systems has been promoted, and as part of this development, electrolyte circulation type metal halogen stacked secondary batteries as illustrated in FIGS. 6 to 8 have been developed. As shown in the structural principle diagram of FIG. 6, the battery main body 1 is divided into an anode chamber 3 and a cathode chamber 4 by a separator 2 made of an ion exchange membrane or a porous membrane.
Electrolyte tanks 9 and 10 are provided in these bipolar chambers and are connected to each other by liquid sending pipes 5 and 6 and liquid return pipes 7 and ₈ for circulating the electrolytic solution, respectively.
The electrolyte is circulated through each electrode chamber. In addition, 11 is an anode, 12 is a cathode,
13 and 14 are both liquid feeding pumps, and 15 is a four-way valve. Therefore, during charging, the electrolyte circulates in the direction of the arrow in the figure, causing the reactions of Zn ⁺⁺ +2e ^- → Zn at the cathode 12 and 2Br ^- →Br ² +2e at the anode 11, and the reaction occurs at the anode 11.
The generated bromine becomes molecules, mixes in the electrolyte, partially dissolves, and mostly becomes a complex by the complexing agent in the anolyte, and is removed from the electrolyte tank 10 on the anode chamber side.
Precipitates and accumulates within the body. Furthermore, during discharge, a reaction opposite to the above reaction formula occurs at each electrode 11, 12 with the electrolyte circulating, and precipitates (Zn,
Br ₂ ) is consumed (oxidized, reduced) on each electrode 11, 12, and electrical energy is released. Further, in the zinc-bromine battery having the construction principle as described above, a stack of multiple cell laminated structures is used as an element of a laminated battery as illustrated in FIG. This consists of a pair of clamping end plates 16, 16 for pinching and holding the entire stack from both ends using bolts, nuts, etc., and laminated end plates 17, 1, which are holding members arranged inside each of the clamping end plates 16, 16.
7, for example, 30 cells are stacked. That is, the current collecting mesh 19 of one electrode end plate 18
Next, the separator plate 21 is stacked via the packing 20, the spacer mesh 22 for maintaining a predetermined distance is stacked, the flat plate intermediate electrode 23 is stacked, and the packing 20 is stacked again. The electrode end plates 18 are stacked so that a total of 30 cells are stacked. A positive electrode manifold 24 and a negative electrode manifold 25, which are liquid flow holes, are provided at the four corners of the stack thus laminated. Furthermore, each separator plate 21 is constructed by integrally molding a frame plate 21a around the separator 2 made of a microporous membrane by injection molding of plastic.
Microchannels 26 are installed in a symmetrical shape on the top and bottom of both plane parts, respectively. The microchannels 26 shown by solid lines on one side of the microchannels 26 uniformly spread the electrolytic solution introduced from the positive electrode manifold 24 on the diagonal line and flow it over the entire surface of the separator 2, or collect the solution therefrom. Further, a microchannel 26 shown by a broken line on the other side introduces and collects the electrolyte from the negative electrode manifold 25. In this way, the unit cells illustrated in FIG. 6 are constructed on both side surfaces of each separator plate 21. D Problems to be solved by the invention The conventional zinc-bromine battery configured as described above is an electrolyte circulation type, and when the battery is not in operation, the electrolyte is drained from inside the cell in order to reduce self-discharge. It is advisable to remove it. However, the separator 2 used in this battery is a microporous membrane, which expands immediately after absorbing liquid, then contracts as it dries, and even when the liquid content is about 60 to 70%, it contracts. However, it stretches again as the liquid content decreases, but it does not return to its original length. Therefore, the separator plates 21 stacked in a stack are separated by the frame plates 21 around the separators 2.
Since a is fixed and cannot be deformed, when the electrolyte is removed from the cell and becomes semi-dry,
Only the separator 2, which is the membrane of the separator plate 21, contracts, and as a result, as shown in FIG. 8, the frame plate 21a
However, there was a problem that the boundary between the separator 2 and the separator 2 could be broken or damaged. In view of the above-mentioned points, the present invention aims to prevent the separator from being damaged even when the operation of pouring and pouring out electrolyte into a battery is repeated. E Means for Solving the Problems The separator for the zinc-bromine battery of the present invention is constructed by covering the required end sides of the separator membrane of the microporous membrane with a band formed in the form of a band of non-woven fabric or plain-woven net, respectively. A feature is that the plates are integrally injection molded to form the separator plate. F Effect By configuring as described above, during injection molding, the fibers of the band are mixed into the frame plate and solidified to act to reinforce it, and this band also acts as a spacer, and the end side part of the separator acts to position it at the center of the cross section of the frame plate. G Example Hereinafter, an example of the separator for a zinc-bromine battery of the present invention will be described with reference to FIGS. 1 to 5. Note that in FIGS. 1 to 5, parts corresponding to the conventional example shown in FIGS. 6 to 8 described above are given the same reference numerals, and detailed explanation thereof will be omitted. FIG. 1 is an enlarged sectional view of a joint between a separator and a frame plate in a battery separator plate, where 2 is a separator and 21a is a frame plate. This separator 2 (product name of Asahi Kasei Corporation)
HIPORE・FD−120, 1.2mm thick microporous membrane)
As shown in FIG. 2, as the first embodiment, a nonwoven fabric containing Lightron (trade name Lightronnet, manufactured by Chitsuso Co., Ltd.: 300 denier, basis weight
Two 10 mm wide bands 27 made of 8 g/m ² , non-woven fabric (fabric weight 60 g/m ² ) are placed one on top of the other, and are placed so as to surround the side portions in a U-shaped cross section as shown in FIG. Then, in the vicinity of the end 27a, a frame plate 21a made of a material made of injection molded high-density polyethylene containing 40% glass fiber, or an ionomer polyvinylidene fluoride containing 20% glass fiber by weight. are integrally molded to form separator plate 2.
form 1. When the frame plate 21a is injection molded in this manner, when the resin melted in the state shown in FIG. so that the end side of the separator 2 is located at the center of the cross section of the frame plate 21a. Furthermore, at this time, the band 27 which is a non-woven fabric is melted and integrated with the frame plate 27a, but at this time, the net-like fibers (the core material is polypropylene and the sheath material is polyethylene) that make up the band 27 are also melted and integrated with the frame plate 27a. It mixes into the frame board 21a and solidifies, becoming a reinforcing material. Note that when the frame plate 21a is injection molded on the end side of the separator 2, conventionally, as shown in the cross-sectional view of FIG. Not only that, but as shown in FIG. 5, when filling the plastic material at high temperature and pressure during injection molding, the end side of the separator 2 was often pushed to one side and molded in a lopsided state. However, in this example, as described above, the end side portion of the separator 2 is
As illustrated in the figure, it is often located at the center of the frame plate 21a. Further, when the end side of the separator 2 reaches the center of the frame plate 21a as shown in FIG. 4, the strength of that portion is high. However, as shown in FIG. 5, if the molding is offset to the frame plate 21a, the strength of that part will be less than half that of the one in FIG. When the separator 2 shrinks when it is wetted and then dried, it always breaks at the boundary between the separator 2 and the frame plate 21a. From this, it can be seen that the structure in which the end side portion of the separator 2 is located at the center of the cross section of the frame plate 21a as in this example can maintain its strength at a high level. Next, a second embodiment of the present invention will be described. In this embodiment, predetermined side portions of the separator 2 are covered with a single band 27 made of a nonwoven fabric containing Lytron, which is the same as that of the first embodiment described above. Frame board 2 in condition
1a is integrally injection molded. Next, as a third embodiment, two sheets of Lightron nonwoven fabric (Lytronnet: 300 denier, fabric weight 8 g/m ² , nonwoven fabric: fabric weight 34 g/m ² ) are stacked on predetermined side portions of the separator 2. The frame plate 21a is integrally injection molded with the band 27 covered thereon. Next, as a fourth embodiment, the band body 27 is constructed from a plain weave net. In other words, this plain weave net has raw yarn: 300 denier d/f, strength 4.4 g/d, elongation 15%, plain weave net: mesh 17/17 (inch), and basis weight 28 g/f.
^m2 , tension 18.6Kg, strength 664g/fabric weight, elongation 27%,
The adhesive strength is 137 g, and the band 27 is made by stacking two sheets, which is placed over a predetermined side portion of the separator 2, and the frame plate 21a is injection molded to form the separator plate 21. . When configured in this way, the plain weave net acts as a spacer during injection molding, and the end sides of the separator 2 are connected to the frame plate 21.
The polyethylene on the surface of the plain weave net melts and becomes integrated with the frame plate 21a, and the polypropylene core material becomes a reinforcing material. Next, as a fifth embodiment, a plain weave net made of the same material as in the fourth embodiment described above is used as a band 27, and this is placed on each predetermined side of the spacer 2, and the frame plate 21a is integrally injected. Shape and compose. Next, as a sixth example, a plain weave net is made of raw yarn:
250 denier d/f, strength 4.3 g/d, elongation 27%,
Plain weave net: mesh 18/18 (inch), area weight 39.88g/ ^m2 , tension 25.6Kg, strength 643g/area weight,
The elongation is 30% and the adhesive strength is 80g, and this is stacked in two to form the band 27, and this is separator 2.
The frame plate 21a is integrally injection molded to cover each predetermined side portion of the frame plate 21a. Next, in order to test the strength of each of the above-mentioned examples, a comparative example was prepared in which a frame plate 21a was injection molded directly onto the circumferential side of the separator 2 having a conventional structure without the band 27. For the first to sixth embodiments described above, one 24-cell stuff battery with an electrode area of 1600 cm ² was assembled, filled with electrolyte, and charged for 8 hours (current density 13.6 mA/cm ² ). , then the electrolyte is removed, left for 16 hours, and then filled with electrolyte and discharged for about 8 hours, which is one cycle.
After repeating 30 cycles, it was left as it was for one week, and when it was disassembled and inspected, none of the separator plates 21 was found to be damaged. In addition, when a battery was assembled using the separator plate 21 of the comparative example under the same conditions as described above, and after repeating the same operation cycle as described above for 5 cycles, a disassembly inspection was performed.
Sixteen of the 24 separator plates 21 were cut at the boundary between the separator 2 and the frame plate 21a. This proves that the strength of the separator plate 21 of this example is extremely high. Next, the tensile strength in the vicinity between the separator 2 and the frame plate 21a was tested. First, as shown in FIG. 3, sample pieces each having a width of 30.0 mm were cut out from the first to sixth examples and the comparative example described above. Then, each of the sample pieces was fixed to a tensile tester with a chuck size of 10 mm at each end of the frame plate 21a and separator 2, and a tensile test was performed at a tensile speed of 50 mm/min, as shown in Table 1 below. The results shown are obtained.

[Table] In the items in the table above, "unbalanced" means:
As shown in FIG. 5, a test was performed on a sample piece in which the end side of the separator 2 was biased toward one side of the cross section of the frame plate 21a. Furthermore, "biting part breakage" refers to the frame board 21a.
This means that the tensile fracture occurred at the boundary line between the sample and the separator 2, and the display of 0/10 in that column means that all of the sample pieces broke at the area other than this boundary line. Moreover, the tensile strength in this table means the breaking strength in a width of 30.0 mm. From the results in Table 1, it can be seen that the samples of Examples 1 to 6 do not cause breakage at the biting part and have improved tensile strength and elongation at break, compared to Comparative Examples. H. Effects of the invention As detailed above, according to the zinc-bromine battery separator of the present invention, the required end sides of the separator are covered with belts made of nonwoven fabric or plain woven net, etc., and the frame plate is attached. Since the separator plate is formed by integral injection molding, the boundary between the separator and the frame plate is reinforced, and this boundary part can be prevented from breaking due to contraction of the separator during use of the battery. There is.

[Brief explanation of the drawing]

FIG. 1 is an enlarged longitudinal cross-sectional view of essential parts showing one embodiment of the separator for a zinc-bromine battery of the present invention, FIG. 2 is a plan view showing a state in which a band is attached to the end side of the separator, and FIG. The figure is a plan view of the main part showing the shape of the tensile sample piece, Figures 4 and 5 are enlarged longitudinal sectional views of the main part showing the joint between the separator and the frame plate, and Figure 6 shows the principle of a conventional battery. A schematic explanatory diagram, Fig. 7 is an exploded perspective view of the stack part which is an element of the battery, Fig. 8 is an exploded perspective view of the stack part which is an element of the battery
The figure is a front view showing separator plates for laminated cells in the stack. 1... Battery body, 2... Separator, 21...
Separator plate, 21a...frame plate, 27...band plate.

Claims (1)

[Claims for Utility Model Registration] In a separator for a zinc-bromine battery in which a positive electrode electrolyte and a negative electrode electrolyte are separated by a separator that is a microporous membrane. Or, a separator for a zinc-bromine battery, characterized in that a separator plate is constructed by covering a belt made of a plain weave net and integrally providing a frame plate thereon.