JPS6324571A - Rotary type zinc-bromine cell - Google Patents

Abstract

PURPOSE:To make the electrolyte circulation device unnecessary and to realize a compact size, by laminating cells of opposing positive and negative electrodes to make an electrode body, housing them in a cell main body of an enclosed structure, and rotating the cell main body at a specific rotational frequency or more. CONSTITUTION:At the periphery of a disk-form positive and negative electrodes 30, a hollow and disk-form frame 32 with manifolds 33a and 33b is furnished, and they are opposed through a separator to make up a cell. Such cells are laminated to form an electrode 23, and assembled together with retaining plates 21 and a rotary shaft 22 to make a cell main body 20 of a zinc-bromine cell. Of the electrodes, at least the positive elctrodes are made with the outside of a carbon plastics combined integrally with an active carbon fiber sheet over the plastics. Then, by rotating the cell main body at 2 rpm or faster to carry out charge and discharge. Therefore, the electrolyte can be fed smoothly without circulation device, and the whole cell can be made in a compact size.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Industrial Field of Application This invention is a compact and lightweight battery, such as a power battery for an electric vehicle, that does not require an attached electrolyte circulation device (electrolytes electrolyte to charge the battery). This invention relates to a sealed bipolar rotating zinc-bromine battery that discharges electricity.

B0 Summary of the Invention This invention provides at least one of the positive and negative electrodes, in which a sheet of activated carbon fiber is integrally bonded to the outside of carbon plastic, and the positive and negative electrodes are made to face each other to form a cell. The stack is housed in a completely sealed battery body, and electrolyte is supplied to each cell for charging and discharging.

Moreover, when charging and discharging, the battery body or electrodes should be heated for 2 hours.

By rotating the electrode for more than 100 m, the bromine complex compound produced (by electrolysis of the electrolytic solution) is diffused over the entire surface of the electrode, thereby increasing the energy efficiency of the battery.

C0 Prior Art Electrolyte circulation type zinc-bromine batteries are currently being developed for practical use as surplus power storage batteries.

FIG. 6 shows the basic configuration of an electrolyte circulation type zinc-bromine secondary battery. The code (1) in the figure is a single cell forming the battery body, (2) is a positive electrode chamber, (3) is a negative electrode chamber, and (4) is a diaphragm.
A positive electrode chamber (2) and a negative electrode chamber (3) are defined. (5) is the positive electrode, (6) is the negative electrode, (7) is the positive electrode side piping system, (8) is the negative electrode side piping system, (9) is the positive electrode electrolyte tank, αQ is the negative electrode electrolyte tank, αη, (6 ) are both pumps, and each piping system (7
), (8) The electrolytic solution (ZnBr1 aqueous solution) 1- is circulated from each electrolytic solution tank (9) and αQ via t-.

Therefore, during charging, ZH+2e→Zn at the negative electrode (6)
, a reaction of 2Br-→Brl+2e occurs at the positive electrode (5), and during discharge, a reaction opposite to the above reaction formula occurs at each electrode (6), (5), and the precipitates (Zn, Brl) form at each electrode (6). , (5) is consumed (oxidized, reduced) and electrical energy is released.

D1 Problems to be Solved by the Invention The above-mentioned electrolyte circulation type zinc-bromine secondary battery has a high energy density (and high battery efficiency).

Since Brz is abundant as a common resource and inexpensive, its use as an energy storage battery is being considered.
Demand is also expected for use in electric vehicles. and,
The characteristics of the electrolyte circulation type are (a) the reactive active material is variable depending on the liquid volume of the electrolyte tank, (b) the uniformity of zinc electrodeposition is increased, and (c) the reaction overvoltage is reduced. An advantage is that it can be done.

However, since it is necessary to circulate the electrolyte in the above battery, an electrolyte circulation device consisting of the battery body, an electrolyte tank, piping system, and a pump is installed as an auxiliary equipment, but when used in an electric vehicle, the device is Since it is complex and bulky, it reduces the loading area and there is a risk of component damage. Therefore, as an alternative to the electrolyte circulation type, a static electrolyte type bipolar zinc-bromine battery that does not require circulation of the electrolyte is considered, but (c) there is a risk of zinc dendrite formation, and (b) reaction The problem was that overvoltage increased.

E3 Means for Solving Problems The rotating zinc-bromine battery according to the present invention is one in which at least one of the positive and negative electrodes is integrally bonded to the outside of a carbon plastic with an activated carbon fiber sheath. The electrodes, which are made by stacking the positive and negative electrodes in pairs to form cells, are housed in a sealed battery body, and when performing electrolytic charging and discharging of the electrolyte in each cell, the battery body or 2 electrodes
The bromine complex compound generated at the positive electrode is supplied to the entire surface of the electrode by rotating at a speed of r, pm or higher.

20 Effects In this invention, at least the positive electrode of the positive and negative electrodes is formed by integrally bonding a sheet of activated carbon fiber to the outside of carbon plastic, and the positive and negative electrodes are paired and treated in a cell. When charging and discharging is performed by electrolyzing the electrolyte supplied to each cell, the battery square or electrode is
, p, m or higher, so that the electrolytic solution is rotated and stirred, electrolyzed, and charged/discharged.

■Of the positive and negative electrodes, at least the surface of the positive electrode is made of activated carbon fiber sheet, and the battery body or electrode is
Since the electrode rotates by more than p and m, the bromine complex compound generated at the positive electrode is diffused and supplied to the entire surface of the electrode, increasing the energy efficiency of the battery.

G. Example Figure wZ1 is a schematic perspective view of an embodiment of the present invention.

In the figure, the handle is the main body of a rotating zinc-bromine battery (21
m), (21b) are disc-shaped presser plates at both ends, (22a
) and (22b) are rotated by a motor with rotating shafts attached to the holding plates (21a) and (21b), respectively.

(2015) is an electrode in which cells are stacked, and the stacked state is maintained by being pressed by holding plates (21a) and (22b) K from both ends of the stack. Each stacked electrode has a diameter of 1 without a hole in the center.
The disk-shaped 'gL electrode of α is used as a positive electrode, and an electrode with the same shape as a negative electrode is placed opposite to this positive electrode through a separator.
A pair of cells. The positive electrode is made by integrally bonding a fiber sheet of phenol resin-based activated carbon to the outside of carbon plastic. The phenol resin-based activated carbon fiber sheet is CC507-1 manufactured by Nippon Kaidol Co., Ltd.
5 (trade name) was used. Carbon plastic is made by mixing carbonaceous materials such as graphite powder or carbon black to impart electrical conductivity to polyolefin resins such as polyethylene, which is anti-bromine as a positive electrode active material, easy to mold, mass-produced, and inexpensive. , mixed wires, and formed into electrodes.

FIG. 2 is a plan view of each of the positive and negative electrodes.

In the figure, (G) is a circular flat electrode, 0■ is a hollow disk frame integrally fixed to the outer periphery of electrode (G), (33m), (33b) is installed on frame 0■ It is a manifold.

As mentioned earlier, the positive and negative electrodes (1) are connected to the manifolds (33a) and (33b) of the frame (A).
) to form a pair of cells with a separator in between. And the stacked cell manifold (32a)
.

(32b) and the electrolyte inlet (c) and electrolyte outlet @ of the holding plate (21b), and the electrolyte flows from the inlet through the manifold (33m) between each cell. It looks like this. The '* pole w in FIG. 1 is a stack of 10 cells each.

FIG. 3 is an overall schematic perspective view of an embodiment of the present invention;
In the figure, (40a) and (40b) are battery support stands, which support rotating shirts (22a) and (22b) with full bearings. 0υ is a rotating shirt) (
22b).

This invention is constructed as described above, and an experiment was carried out in which an electrolytic solution of ZnBr2 + bromine complexing agent was injected from the electrolytic solution injection port (c) while the battery main body (1) was rotated by a motor at 0υ. I did it. In addition, charging is at a constant current of 20 mA/- at 8
Time went.

When the electrolyte is injected from the electrolyte inlet (c) and the battery body is rotated, the electrolyte will flow from the manifold (roa 3).
The fuel is supplied to each cell in parallel, rotated and stirred within each cell as shown by the arrows in FIG. 2, and charged and discharged through an oxidation-reduction reaction.

As a result of the experiment, it became clear that the relationship between the rotation speed of the electrode (1) and the energy efficiency of the battery was as shown in FIG. 4.

Incidentally, FIG. 4 is a diagram showing the relationship between the energy efficiency of the battery and the number of revolutions of the electrodes of the battery. From the results shown in FIG. 4, a decrease in energy efficiency was observed when the rotation speed of the electrode (7) was 1r, p, and m, but when the rotation speed was 2r, p.

Above m, the energy efficiency was approximately constant at around 71%. It has become clear that even in such a practical battery, it is sufficient for the rotational speed of the electrode (1) to be 2r, p, m.

Next, in order to clarify the influence of the rotation of the electrode (1) on the energy efficiency of the electrode, the energy efficiency of charging and discharging was investigated when the electrode (1) was rotated and when it was stationary. Incidentally, FIG. 5 shows the relationship between the charging/discharging time of the battery and the battery voltage when the battery is rotating and stationary. The results of the experiment are shown in Table 1 below.Table 1 From the results in Table 1, the energy efficiency of the battery decreases when the electrodes are stationary during discharge. This is because the generated bromine complex compound accumulates in the lower part of the electrode (7) and the upper part of the stain electrode (1) is not used effectively. Also, the reason why the energy efficiency is lower when the electrode (1) is stationary than when it is rotated during charging is because bromine complex compounds accumulate at the bottom of the positive electrode (1), and the liquid resistance at that part increases. This is because zinc tN also deteriorates due to an increase in the current distribution and a disturbance in the current distribution. From the above reduction in energy efficiency and the phenomena that cause it, the effect of rotation of the electrode (1) is closely related to the wave number of the bromine complex compound generated at the positive electrode.
This is due to the small contribution of the reduction overpotential of the electrochemical reaction.

Moreover, in this invention, an electrode (7) in which a fiber sheet of phenol resin-based activated carbon is integrally bonded to the outside of carbon plastic is used as the positive electrode, and the surface of the positive electrode in contact with the electrolyte has microscopic irregularities. .

Therefore, the surface condition of the positive electrode and the rotation of the electrode (1) will cause the bromine complex compound that accumulates at the bottom of the positive electrode (1) to diffuse, and the bromine complex compound will be distributed and supplied to the entire surface of the electrode, which will be a factor in improving energy efficiency. . Furthermore, since the electrode (1) is round, the electrolyte rotates smoothly as shown by the arrow in FIG. Moreover, by providing a hole in the center of the electrode (7),
Since there is no means for inserting the rotating shafts (22a) and (22b) into the holes, and the entire surface of the electrode (1) is a flat plate, the effective area of the electrode (1) is large. , and the electrolyte rotates smoothly, contributing to improved energy efficiency. Further, when the battery was disassembled and observed after the charge/discharge experiment was completed, zinc electrodeposition was better when rotation was applied, and there was no significant dendrite formation.

Moreover, the reason why the Coulombic efficiency is better when rotation is applied is because the uniform solubility of zinc is improved by the rotation of the electrolytic solution. Bromine in the positive electrode is a bromine complex compound, and it is thought that when the electrode (7) is rotated, the bromine complex compound also reacts.

H1 In the detailed explanation of the invention, in 5, this invention is such that at least the positive electrode of the positive and negative electrodes is formed by integrally bonding an active fiber sheet to the outside of carbon plastic, and the positive and negative electrodes are opposed to each other. The electrodes, which are stacked in pairs to form cells, are housed in a battery body with a sealed structure, and when charging and discharging is performed by electrolysis of the electrolyte in each cell, the battery body or electrodes are
Since the rotation is made more than p, m, the following effects can be obtained.

■Since the electrolyte circulation device required for stationary batteries is not required, the entire battery can be made lighter and more compact, making it easy to use in vehicles with limited loading weight and loading space. be able to.

■ Even when the battery body or electrode rotation speed is as low as 2r, p, or m, it has high energy efficiency, is easy to handle, and has great mechanical durability.

[Brief explanation of the drawing]

Fig. 1 is a schematic perspective view of an embodiment of the present invention, Fig. 2 is a plan view of an electrode, Fig. 3 is an overall schematic perspective view of an embodiment of the invention, and Fig. 4 shows the rotation speed of the electrode. Figure 5 is a diagram showing the relationship between battery energy efficiency and Figure 6 is a diagram showing the relationship between charging and discharging time and battery voltage for rotating batteries and stationary batteries.
The figure is an explanatory diagram showing the basic configuration of a conventional electrolyte circulation type zinc-bromine secondary battery. In the figure, the handle is the main body of a rotating zinc-bromine battery (21
a), (21b) are presser plates, (22a), (22b)
) is the rotating shaft, the wire is the electrode with stacked cells, (c)
(c) is an electrolyte solution inlet, (1) is a frame, (33a). (33b) is a manifold, (40m), (40b)
is the battery support stand and αυ is the motor. Agent Patent Attorney Tadashi Sato Group 1, Figure 2, Figure 4 Compensation] &'s Rotating Group (rpm) 5th Inko Kl! IM? (Hv) Figure 6 O■

Claims (1)

[Scope of Claims] A zinc-bromine battery (a) having positive and negative electrodes, of which at least the positive electrode is integrally bonded to an activated carbon fiber sheet on the outside of carbon plastic. (c) The above electrode is a cell made up of a pair of positive and negative electrodes positioned opposite each other, and the cells are stacked, (d) The electrode in (c) above is formed into a sealed structure. (e) When charging and discharging by electrolyzing the electrolyte solution supplied to each cell, the battery body or the electrodes are placed in a 2r. p. A rotating zinc-bromine battery, characterized in that it rotates at a speed of m or more.