JPH0672162U - Laminated structure of zinc-bromine battery - Google Patents

Abstract

(57) [Abstract] [Purpose] When the bolts are tightened between the tightening end plates of the battery body components to integrally stack them, the entire device is downsized, and the structure is caused by the excessive tightening force of the spring. The purpose is to prevent the material from cracking and to reduce the weight and cost. Constitution: Zinc integrally laminated and fixed by uniformly tightening between the two tightening end plates 21 and 21 (glass epoxy plate) of the battery body 20 with a plurality of bolts 15 with a coil spring 22 interposed therebetween. It has a laminated structure of a bromine battery.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a laminated structure of an electrolyte circulating type secondary battery, particularly a zinc-bromine battery for power storage.

[0002]

[Prior art]

 Zinc-bromine batteries are secondary batteries that use bromine as the positive electrode active material and zinc as the negative electrode active material. For example, this battery is used at night when power demand is low to solve the imbalance between day and night. Electricity is being stored and released in the daytime, and development for electric vehicles is in progress.

Bromine generated on the positive electrode side at the time of charging reacts with the bromine complexing agent added to the electrolytic solution to be returned to the positive electrode side storage tank as an oily precipitate, and at the time of discharging, a single cell is pumped. It is sent in and returned. The components of the electrolytic solution are a ZnBr ₂ aqueous solution, a salt such as NH ₄ Cl for reducing the resistance, and Pb, Sn, and quaternary ammonium for preventing dendrites on the zinc side of the negative electrode and promoting uniform electrodeposition. A salt and a bromine complexing agent. A separator is inserted between the positive electrode and the negative electrode to prevent self-discharge due to the bromine generated in the positive electrode diffusing into the negative electrode and reacting with zinc.

This zinc-bromine battery mainly has a bipolar type electrode, a battery body in which a plurality of cells (cells) are electrically stacked in series, an electrolytic solution storage tank, and an electrolytic solution storage tank between them. It consists of a pump and a piping system that circulates the electrolyte.

FIG. 3 is an exploded perspective view showing an example of a battery main body that constitutes the zinc-bromine battery, and an insulating frame 1b is arranged on the outer periphery of the electrode portion 1a of the bipolar plate-shaped intermediate electrode 1 having a rectangular flat plate shape. Similarly, in the separator plate 2 having a rectangular flat plate shape, the frame body 2 a is formed on the outer periphery of the separator 3. The separator plate 2 and, if necessary, the packing 4 and the spacer mesh 5 are stacked on the intermediate electrode 1 to form a single cell, and a plurality of the single cells are laminated to form a battery body.

A collector electrode 7 having a collector mesh 6, a pair of tightening end plates 8 and a stacking end plate 9 for pressing, which is located inside the collector electrodes 7, are provided at both ends of the stacked battery bodies. It is arranged. Then, a bolt for fastening, which will be described later, is passed between the fastening end plates 8 and 8 and the bolt is fastened to form a battery body integrally laminated and fixed.

In each unit cell of the battery main body configured as described above, the positive electrode manifold 10 formed at the upper and lower two corners of the frame 2 a of each intermediate electrode 1 and the separator plate 2, The electrolyte solution flows in and out from the negative electrode manifold 11 through the channels 12 and the microchannels 13 provided in the frame body 2a of the separator plate 2, respectively.

Then, the positive electrode electrolyte is circulated in the single cell from the positive electrode manifold 10 of the battery main body to be returned to the positive electrode side storage tank by driving the positive electrode side pump from the positive electrode side storage tank arranged outside. The negative electrode electrolyte is circulated from the negative electrode manifold 11 of the battery main body in the unit cell separated by the separator 3 by the drive of the negative electrode side pump and returned to the negative electrode side storage tank.

The above zinc-bromine battery has been confirmed to have a battery efficiency of about 80% and a total energy efficiency of about 70% in a 50 KW class battery.

FIG. 4 shows a module structure of a battery body in which the above-mentioned respective components are assembled. One sub-module includes a plurality of cells C ₁ or C ₂ , C ₃ stacked in series. One unit is used, and in the illustrated example, a total of three units of the sub-module are used to tighten the tightening bolts 15 and 15 inserted between the tightening end plates 8 and 8 with the disc springs 16 and 16 interposed. It is fixed. The disc springs 16 and 16 have a function of preventing cracks and the like from being generated in the components due to stress concentrated on the interface when the tightening end plates 8 and 8 are tightened using the bolts 15 and 15. It has the function of preventing destruction due to expansion and contraction of components due to changes in temperature and heat generated during charging and discharging, and has the effect of minimizing the load changes exerted on the components.

Usually, the tightening end plate 8 is made of a fiber reinforced plastic resin (FRP), the frame body 1b of the intermediate electrode 1 is made of vinyl chloride resin (PVC), and the separator plate 2 is made of a relatively hard polyethylene resin. Has been adopted.

[0012]

[Problems to be solved by the device]

 However, the laminated structure of the battery main body in the above zinc-bromine battery is liable to increase the size of the entire device and may cause cracks in the constituent materials due to excessive tightening force of the disc spring. is there.

That is, the tightening bolts 15 and 15 inserted between both the tightening end plates 8 and 8 in FIG. 4 fix the battery main body through the disc springs 16 and 16. However, in order to prevent breakage due to expansion and contraction of the constituent materials and to minimize the load change, it is necessary to increase the number of the disc springs 16 and 16, and therefore it is inevitable. This tends to lead to an increase in the size of the device. For example, the length of the disc spring 16 may occupy as much as ⅕ of the total length of the battery main body, which increases the battery installation space.

Further, since the tightening force of the disc spring 16 itself may change in the direction of weakening the tightening force of the disc spring 16 against the battery body, the shrinking allowance is predicted in advance and the tightening force at the beginning of the head is determined. If determined, excessive pressure will be applied to the constituent materials of the battery main body, and there is a problem that cracks may occur in the constituent materials such as the tightening end plate 8. Further, in order to deal with the cracks, there is a means of increasing the thickness of the intermediate electrode or the constituent materials such as the separator plate, but there is a problem that it is not preferable in terms of weight and cost.

The present invention has been made in view of the above points, and it is possible to reduce the size of the entire apparatus and prevent cracks in components due to excessive tightening force of a spring, thereby reducing weight and cost. It is an object of the present invention to provide a laminated structure of a zinc-bromine battery which is also effective in view of the above.

[0016]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the present invention has a separator plate and an intermediate electrode stacked to form a single cell, and a plurality of the single cells are stacked to form a battery main body, and a current collector is provided at both ends of the battery main body. Place a collecting electrode having a mesh, a laminated end plate for pressing and a pair of tightening end plates, and tighten both tightening end plates with a plurality of bolts with a spring interposed. In a zinc-bromine battery that is integrally laminated and fixed by means of the above, a laminated structure of a zinc-bromine battery in which a coil spring is interposed between both tightening end plates to evenly tighten a plurality of bolts. I am doing it.

[0017]

[Action]

 According to such a laminated structure of the zinc-bromine battery, when the battery body is heated by tightening both tightening end plates under a predetermined tightening condition using a plurality of bolts through which coil springs are inserted. Expansion causes the coil spring to contract and the tightening force of the bolt to increase.However, the increase rate of the total tightening force of the bolt is The disc spring is much larger. Therefore, by adopting a coil spring as in the present embodiment, the length of the spring itself can be shortened, and the battery main body in the expanded state of the battery main body can be shortened. Since the applied load is greatly reduced in the coil spring, the occurrence of cracks or strains in the components due to excessive tightening force of the bolts is prevented.

Furthermore, since the burden of tightening the bolts at the beginning of the head is reduced, it is possible to reduce the thickness of the components such as the intermediate electrode and the separator plate, which improves the battery characteristics and lowers the cost. It brings about the action of being converted.

[0019]

【Example】

 An embodiment of a laminated structure of a zinc-bromine battery according to the present invention will be described below with reference to the drawings.

In this embodiment, as shown in FIGS. 1 and 2, first, a battery main body 20 made of cells C _{N in} which _N sub-modules are laminated in series and the laminated portion of the outer peripheral four sides is peripherally sealed is manufactured. Then, the glass epoxy plates 21 and 21 are arranged in close contact with both ends of the battery body 20. The glass epoxy plates 21 and 21 correspond to the tightening end plate 8 in FIG.

Next, a coil spring 22 is arranged outside one of the glass epoxy plates 21, and the bolts 15 and 15 and the nuts 23 and 23 for tightening which are inserted in the coil spring 22 are used to remove both glass epoxy plates. The plates 21 and 21 are evenly clamped and fixed. Reference numerals 24, 24 are holes for manifolds opened in the glass epoxy plates 21, 21.

Therefore, the glass epoxy plates 21 and 21 are evenly tightened by the plurality of bolts 15 and 15 inserted through the interposition of the coil spring 22. In the illustrated example, a total of 10 bolts 15 are used.

As a specific dimension, the battery main body 20 was formed by stacking cells having an electrode area of 830 cm ² by a 64-cell hot plate welding method to obtain 502 ^W × 251 ^H × 215 ^L. As the coil spring 22, a star die spring having an outer diameter of 20 mm and a length of 30 mm for heavy load was used.

The operational features of the laminated structure will be described below. That is, the linear expansion coefficient of the battery main body 20 is 3 × 10 ⁻⁴ , and when the operating temperature range of the battery is 0 to 50 ° C. (ΔT = 40 deg), 3 × 10 ⁻⁴ × 215 ^L = Expansion and contraction of 2.6 mm will occur.

On the other hand, the glass epoxy plates 21 and 21 were fastened with the bolt 15 inserted through the coil spring 22 at a temperature of 10 ° C. with a force of 70 kgf / piece. The length of this coil spring 22 is 25.8 (70 / 16.66 = 4.2 mm contraction, 16.66 is a spring constant). When the battery main body 20 was placed in a constant temperature bath and heated to 50 ° C., the total length extended by 2.6 mm and the coil spring 22 contracted by 2.6 mm. At that time, the tightening force of the bolt 15 was 113 kgf (16.66 × 2.6 = 43 kgf was stronger).

That is, the total tightening force of the 10 bolts is increased from 700 kgf to 1130 kgf.

On the other hand, for comparison, a disc spring having an inner diameter d of 8.2 mm, an outer diameter D of 16 mm, a thickness of 0.9 mm and a height of 1.25 mm (heavy load disc spring JIS2706 No. 8) is used. The battery body 20 manufactured in the same manner as above was fastened together with the bolt 15 at a temperature of 10 ° C. and a force of 70 kgf / piece.

The length of this disc spring before tightening is (1.25 + 0.9) × 15 = 32.3 mm, and after tightening, the flexure becomes σ≈0.25 h (σ = 0. When it was used in two rows with 71 kgf at 0.5 h), the length was reduced by (1.25-0.9) × 0.25 × 15 = 1.3 mm to 31 mm.

When the battery main body 20 was placed in a constant temperature bath and warmed to 50 ° C. in the same manner as described above, the battery main body 20 expanded by 2.6 mm and the disc spring contracted by 2.6 mm to 28.4 mm, and the deflection σ≈ Since it was 0.75 h, the tightening force was 105 × 2 = 210 kgf.

That is, the total tightening force of the 10 bolts is increased from 700 kgf to 2100 kgf.

When the glass epoxy plates 21 and 21 are tightened as in the above-described embodiment, if the coil springs 22 are interposed and the bolts 15 are used to uniformly tighten the springs, the length of the springs itself becomes small and at the same time the battery It was confirmed that the load applied to the battery body 20 when the body 20 was stretched was significantly reduced.

That is, even in the case of the present embodiment, the coil spring 22 contracts due to the expansion when the battery body 20 is heated, and the tightening force of the bolt 15 increases. The rate of increase in the total tightening force of the bolt 15 is much larger in the conventional countersunk plate than in the case of performing the above. Therefore, by adopting the coil spring 22 as in this embodiment, The length of the coil spring 22 itself can be shortened, and the load applied to the battery main body 20 when the battery main body 20 is expanded is significantly reduced in the coil spring 22. Therefore, it is possible to obtain an effect that no crack or distortion of each component of the battery body 20 due to the excessive tightening force of the bolt 15 is generated.

[0033]

[Effect of device]

 According to the laminated structure of the zinc-bromine battery according to the present invention described in detail above, the following operational effects can be obtained. That is, the rate of increase in the tightening force of the bolt due to the contraction of the coil spring due to the expansion of the battery body is much smaller than the similar rate of increase using the conventional disc spring. The length can be shortened, and the total length of the battery main body can be shortened, and the effect is that the installation space for the battery can be reduced.

Further, cracking or distortion of the constituent materials due to excessive tightening force of the bolt when the battery main body is expanded is prevented, and the burden of the bolt tightening force at the beginning of the head is reduced. Therefore, it is not necessary to increase the thickness of the components such as the intermediate electrode and the separator plate, which has an effect that the weight of the battery itself is reduced and the cost is reduced.

[Brief description of drawings]

FIG. 1 is a schematic view of a battery body to which a laminated structure of a zinc-bromine battery according to the present invention is applied.

FIG. 2 is a perspective view showing an assembling mode of a battery body.

FIG. 3 is an exploded perspective view showing the structure of a zinc-bromine battery body.

FIG. 4 is a schematic diagram showing a module structure of a battery main body in which each component is assembled.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Intermediate electrode 2 ... Separator plate 3 ... Separator 8 ... Tightening end plate 9 ... Laminated end plate 10 ... Positive electrode manifold 11 ... Negative electrode manifold 12 ... Channel 13 ... Micro channel 15 ... Bolt 20 ... Battery body 21 ... Glass epoxy plate 22 … Coil spring 23… Nut 24… Hole

Claims (1)

[Scope of utility model registration request] 1. A separator cell and an intermediate electrode are stacked to form a single cell, and a plurality of the single cells are stacked to form a battery main body, and a current collecting electrode having a current collecting mesh at both ends of the battery main body. , Arranging a laminated end plate for pressing and a pair of tightening end plates, and tightening between the two tightening end plates with a plurality of bolts with a spring interposed, so that they are integrally laminated and fixed. In the zinc-bromine battery described above, a coil spring is interposed between both the tightening end plates to uniformly tighten a plurality of bolts.