JPH06251808A - Manufacture of zinc-bromine battery - Google Patents

Abstract

PURPOSE:To assemble a battery mainframe under almost the best conditions by finding the minimum fastening force on bolts from test pieces and applying necessary face pressure, lib area and disc spring constants as factors thereto. CONSTITUTION:Test pieces which are made up of the same material as separator plates 2 have and test pieces which are made up of the same material as middle electrodes have and arranged between the preceding test pieces are each fastened with fastening bolts. After libs which are protruded on both faces of the center test piece are adhered to the faces of the test pieces on both sides for assembly until they are thrusted and deformed, 1-atmospheric- pressure air is introduced from a pressure source through a valve, a pressure gage and a connection jig inward of the test pieces on both sides and in the meantime its pressure change is checked. The tension of the bolts at the time when no pressure change occurs is measured. Next, during assembling a battery mainframe, the middle electrode and the separator 2 are fastened with the bolts in the way of applying the same tension to the bolts at positions A-H, K-Q.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an electrolyte circulating type laminated secondary battery, in particular a zinc-bromine battery for power storage.

[0002]

2. Description of the Related Art A zinc-bromine battery is a secondary battery that uses bromine as a positive electrode active material and zinc as a negative electrode active material.
It is used to store electricity at night when electricity demand is low and to release it in the daytime.

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 oil-like precipitate, and at the time of discharging, it is pumped to the unit cell. It is sent in and returned. The component of the electrolytic solution is ZnBr
₂ aqueous solution, a salt such as NH ₄ Cl for reducing resistance, Pb, Sn, quaternary ammonium salts for preventing dendrite on the negative electrode zinc side and promoting uniform electrodeposition, and a bromine complexing agent Is. A separator is inserted between the positive electrode and the negative electrode to prevent self-discharge caused by the bromine generated in the positive electrode diffusing into the negative electrode and reacting with zinc.

In this zinc-bromine battery, the electrodes are mainly of a bipolar type, a battery body in which a plurality of unit cells (unit cells) are electrically stacked in series, an electrolytic solution storage tank, and an electrolytic solution between them. It is composed of a pump and a piping system for circulating the liquid.

FIG. 9 is an exploded perspective view showing an example of a battery main body which constitutes the above zinc-bromine battery, in which an insulating frame 1b is arranged on the outer periphery of an electrode portion 1a of a bipolar flat intermediate electrode 1 having a rectangular flat plate shape. Similarly, a rectangular flat plate-shaped separator plate 2
The frame 2a 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 stacked to form a battery body.

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

In each unit cell of the battery body constructed as described above, each intermediate electrode 1 and the frame body 2a of the separator plate 2 are provided.
Positive electrode manifold 10 formed in two corners above and below
Then, the electrolytic 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.

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. 10 is a schematic diagram for explaining the operating principle of the zinc-bromine battery, in which 14 is a positive electrode side storage tank in which the positive electrode electrolyte solution 15 and bromine are stored. Complex compound 16 is stored. Reference numeral 17 denotes a negative electrode side storage tank in which the negative electrode electrolytic solution 18 is stored. The positive electrode electrolyte solution 15 is used as the positive electrode side pump 1.
With the driving of 9, the inside of the single cell flows from the positive electrode manifold 10 of the battery main body through the four-way valve 20 as shown by the arrow in the figure and flows back to the positive electrode side storage tank 14, while the negative electrode electrolytic solution 18 As the negative electrode side pump 21 is driven, it flows through the single cell separated from the negative electrode manifold 11 of the battery body to the separator 3 and returns to the negative electrode side storage tank 17.

FIG. 11 shows a module structure of a battery main body in which the above-mentioned components are assembled. One sub-module comprises 30 cells C ₁ or C ₂ , C ₃ stacked in series as one unit. In the illustrated example, the sub-module is based on a total of 3 units, that is, 90 cells.
Incidentally, 22 is a tightening bolt inserted between both tightening end plates 8 and 23 is a disc spring. This disc spring 23
The function of preventing cracks and the like from being generated in the components due to the stress concentrated at the interface when tightening between the tightening end plates 8 using the bolts 22 and the change in the outside temperature or the heat generated during charging / discharging. It has a function of preventing breakage due to expansion and contraction of the constituent material, and has an action of minimizing a load change exerted on the constituent material.

Usually, the tightening end plate 8 is made of fiber reinforced plastic resin (FRP), and the frame body 1 of the intermediate electrode 1 is used.
A vinyl chloride resin (PVC) is used for b, and a relatively hard polyethylene resin is used for the separator plate 2. 12
Reference numeral 24 denotes a hole for the manifold.

In manufacturing the module of the battery main body, after stacking the above-mentioned constituent materials mainly composed of plastics, a press of about 20 tons and a hot water circulating step are repeated a plurality of times, and a bolt 22 is used for tightening. After that, a method of performing a seal test using air is implemented. The number of days required for all processes is about 8 days / vehicle.

FIG. 13 shows a specific structure of the separator plate 2. As shown in FIG. 14 which is a sectional view taken along the line AA in FIG. 13, both sides of the channel 12 connected to the positive electrode manifold 10 are shown. Ribs 25, 25 project from the ribs 25, 25, and the ribs 25, 25 define the flow path of the electrolytic solution.

[0014]

However, in manufacturing the above zinc-bromine battery, the minimum tightening force of the bolt 22 and the final tightening of the bolt 22 for coping with the creep caused by the temperature change. There is a problem that the sealability may deteriorate with time because no clear index is set regarding the magnitude of force and the like.

More specifically, as shown in FIG. 14, ribs 25 projecting from both sides of the channel 12 define the flow path of the electrolytic solution, which affects the tightening force of the bolt. It is not clear what the effect of the rib area is, and the criteria for what the minimum surface pressure of the rib should be have not been established. Therefore, it is not clear whether the conditions such as the manufacturing process and tightening pressure that are currently being implemented are the best, and it is the current situation that these conditions are empirically determined. There are problems that cracks may occur due to excess and electrolyte may leak due to deterioration over time.

Further, when manufacturing the module of the battery main body, the pressing step is carried out after laminating the respective constituent materials. In this pressing step, one battery main body must be processed by one pressing machine. Therefore, the number of days required for all the processes is long, and it is difficult to improve the production efficiency.

The present invention has been made in view of the above points, and an object thereof is to determine the best manufacturing process and conditions and to provide a clear index at the time of manufacturing.

[0018]

In order to achieve the above object, the present invention provides a battery main body in which a separator plate having ribs and an intermediate electrode are stacked to form a single cell, and a plurality of the single cells are stacked. And a stacking end plate for holding and a pair of tightening end plates are arranged, and a disc spring is provided between both tightening end plates. In a zinc-bromine battery that is integrally laminated and fixed by bolting under the interposition of, the separator plate and the intermediate electrode, which are constituent members of the battery main body, are stacked, and the separator plate and the intermediate electrode are previously formed. The minimum tightening force of the bolt is obtained by the test piece using the same constituent material, and this minimum tightening force is necessary to saturate the creep amount of the constituent material caused by the ambient heat change and the creep in a short time. Surface pressure and separator The final tightening force can be determined by adding the area of the ribs protruding from the plate, the disc spring constant and the number of tightening bolts as factors, and tightening the bolts evenly diagonally. A method for manufacturing a zinc-bromine battery as a basic means is provided.

The minimum tightening force U is U = (air pressure of 1 atm) × (electrode area + flow channel area) + (rib area) × (minimum surface pressure) ... ........................ Calculated by the formula (1), and the final tightening force W is W = (surface pressure required to saturate the creep of the constituent material) x (rib area) + (Creep amount) × (Disc spring constant) × (Number of springs) ... .. Calculated by the formula (2).

Further, the tightening force of one bolt is tightened so as not to exceed (final tightening force / number of bolts), and finally the tension of all bolts is the above (final tightening force / number of bolts). The amount of contraction of the disc spring is adjusted so that

Further, in the present invention, after uniformly tightening a plurality of bolts, the contraction amount of the disc spring is adjusted so that the tension of all the bolts becomes the above (final tightening force / the number of bolts), and the battery main body is adjusted. (EN) Provided is a manufacturing method in which hot water is circulated therein, followed by cooling, draining water, and then re-tightening lowered bolts to adjust the tightening force of all the bolts. The tightening force W'of the bolt after draining water after this hot water circulation is W '= (minimum tightening force) + (disc spring constant) x (thermal expansion and contraction amount) x (number of bolts) ...・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ (3) Calculate using the formula.

[0022]

According to such a method for manufacturing a zinc-bromine battery, the minimum tightening force U of the bolt is given as a clear index, and the amount of creep or rib area generated with temperature change,
By using the final tightening force W obtained by calculation using the disc spring constant as a factor, it becomes possible to carry out the tightening work of the bolt under the conditions close to the best. Then, the sealing property of the obtained battery body does not deteriorate with time, leakage of the electrolytic solution is eliminated, and cracks or strains of the constituent materials due to excessive tightening force of the bolts are prevented.

Since the burden of tightening the bolts is further reduced, the thickness of the components such as the intermediate electrode and the separator plate can be reduced, and the battery characteristics can be improved and the cost can be reduced. Bring

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the method for manufacturing a zinc-bromine battery according to the present invention will be described below in detail with reference to the accompanying drawings, in which the same components as those of the conventional components are designated by the same reference numerals.

FIGS. 7 and 8 show an example of an apparatus for carrying out a preliminary experiment of the present invention, which is a minimum surface pressure for withstanding the seal test using air after tightening each of the constituent materials with bolts. 2 shows a device configuration for measuring That is, the test piece 30 made of the same material as the separator plate 2
And a test piece 3 made of the same material as the intermediate electrode 1.
1, 31 were prepared, the test piece 30 was arranged between the test pieces 31, 31, and then each test piece was tightened by a plurality of tightening bolts 22, 22 to project on both sides of the test piece 30. After assembling the ribs 32 and 32 so that they are pressed against the surface of the test piece 31 until they are deformed, the ribs 32 and 32 are attached from the pressure source (not shown) to the valve 2
Air of 1 atm was introduced into the inside of the test piece 31 through the pressure gauge 28, the connection jig 29, and the pressure change after leaving it for 100 hours was checked.

Then, the tension of the bolt 22 when no change in atmospheric pressure is observed is measured using a strain gauge, and the surface pressure of the ribs 32, 32 when the same tension as this tension is applied is measured using pressure sensitive paper. It was measured.

From the above surface pressure measurement results, the minimum surface pressure is 10
It has been found that kgf / cm ² is sufficient. From this, the minimum tightening force U by the bolts 22 and 22 can be calculated by the following formula.

U = 1 kgf / cm ² (1 atm air pressure) × (electrode area + flow path area) + rib area × 10 kgf / cm ² (minimum surface pressure) ... (1) the electrode area 1700 cm ² in the actual battery, the rib area of 120 cm ^2, the flow channel area is 400 cm ^2. Substituting this into equation (1) and calculating, the minimum tightening force U is 3.
It will be 3 tons. In order to realize this, it is necessary that the surface pressure is uniform over the ribs.

Next, as shown in FIG. 1, when assembling the battery main body, the intermediate electrode (not shown) and the separator plate 2 are separated by A to A.
When tightening with multiple bolts so that the tension of each bolt at the parts shown in H, K to Q is the same, and measuring the surface pressure (kgf / cm ² ) of the same part using pressure sensitive paper , A to H, K to Q of the separator plate 2 as shown in FIG.
It was found that the surface pressure at the parts up to was almost uniform.

FIG. 3 shows the results of the seal test of the battery body after the above-mentioned assembly is completed. The pressure (atmospheric pressure) of 1 atm of air held at the start after 100 hours has passed, It is a graph plotted in correlation with the tightening force (ton), and a line S in the drawing shows the minimum tightening force. The minimum tightening force by this line S is in good agreement with the minimum tightening force U (3.3 ton) calculated by the above equation (1). In the experiment, even if the minimum tightening force U was 2.9 ton, no electrolyte leakage occurred.

On the other hand, the temperature of the zinc-bromine battery rises to 30 to 40 ° C. due to the outside air temperature or the heat generated during charging / discharging, and due to the influence of this temperature, the laminated portion of the constituent material mainly made of plastic creeps. As a result, the disc spring 23 expands, the tightening force of the bolt 22 weakens, and the sealing performance of the electrolytic solution may deteriorate.

In order to eliminate the creep phenomenon at the time of use, if the temperature and the surface pressure at the time of manufacturing are raised, and conversely, the creep phenomenon of the constituent materials is completely performed in the manufacturing process,
It is possible to prevent the deterioration of the sealing property with time due to the subsequent creep.

Then, the creep characteristics of the separator plate 2 were measured, and as shown in FIG.
It was found that the creep amount was saturated in about 15 hours if the pressure was 0 kgf / cm ² or more. The creep amount at this time is 30
It was about 3 mm per cell. Further, the frame material of the intermediate electrode 1 showed only a small initial change and no change with time.

FIG. 5 is an enlarged cross-sectional view of the interface portion between the intermediate electrode 1 and the separator plate 2 after circulating hot water. The shape of the rib 25 is greatly changed and the sealing area with the intermediate electrode 1 is increased about three times. Was confirmed. The effect of increasing the sealing area of the rib 25 is great, and when the tightening force is the same before and after the hot water circulation, the sealing property is good even if the surface pressure becomes 1/3, as shown in FIG. It was found that the air holding pressure was substantially linear except for the initial standing time.

Further, regarding the thermal expansion of the separator plate 2 with respect to the temperature change, about 90 mm is about 5 mm at a temperature change of 20 ° C., and this is a change of 0 to 40 ° C. at the time of manufacturing, which is ±±. The displacement amount is smaller than the displacement of 5 mm.

The most suitable manufacturing method based on the above results will be described below. The basic conditions are the same even if the number of cells in the battery body, the disc spring constant, and the like change.

(1) The battery body has 90 cells, and the respective constituent materials are laminated to set a disc spring.

(2) The final tightening force between the tightening end plates using the bolt 22 is W = 30 (kgf / cm ² ) × 120 (cm ² , rib area) +9 mm (creep amount) × 12 .8 (kgf / mm, disc spring constant) × 18 (number of springs) = 5.7 ton ... (2) Here, 30 (kgf / cm ² ) is the surface pressure required to saturate the creep in a short time.

(3) Next, the tightening force of one bolt is 5.7.
The bolts 22 are diagonally tightened so as not to exceed the force of ton / 18, and finally the contraction amount of the disc spring 23 is adjusted so that the tension of all the bolts 22 becomes the above-mentioned 5.7 ton / 18.

(4) Hot water at 40 ° C. is circulated in the battery body for 20 hours and then cooled.

(5) The re-tightening force W'of the bolt 22 which has decreased after draining water is adjusted based on the following equation.

W ′ = 3.3 (ton) +12.8 (kgf / mm, disc spring constant) × 5 (mm) × 18 = 4.5 ton ··· (3) Here, 3.3 (ton) is the minimum tightening force obtained by the above equation (1), and 5 (mm) is the displacement amount at a temperature of 20 ° C. still,
The disc spring 23 to be used needs to have a margin of 5 mm for the thermal expansion from the place where it is tightened at 4.5 ton according to the formula (3).

(6) Seal test using air (1 atm,
10 hours).

By carrying out the steps (1) to (6) described above, it becomes possible to give the obtained battery body the sealing characteristics shown in FIG. Then, even after the hot water circulation thereafter, there is almost no change in the unit thickness due to the creep, and it becomes possible to maintain the good sealing property even after the continuous operation of the battery.

[0045]

According to the method for manufacturing a zinc-bromine battery according to the present invention described in detail above, the following operational effects can be obtained. That is, the minimum tightening force of the tightening bolt was given as a clear index, and the surface pressure, rib area, and disc spring constant necessary to saturate the amount of creep generated with temperature change were added as factors. As a result, the bolt tightening work can be performed using the final tightening force obtained by the calculation, and the battery main body can be assembled under the conditions close to the best.

The sealability of the battery body obtained by applying the present invention does not deteriorate with time, the leakage of the electrolytic solution is eliminated, and the tightening force does not become excessive.
The load on the interface between the electrodes and the laminated end plate is minimized, and the occurrence of cracks or distortions in the constituent materials can be prevented and the product life can be extended.

Further, since the thickness of the components such as the intermediate electrode and the separator plate can be reduced along with the reduction of the above-mentioned burden, the effect of improving the battery characteristics and reducing the cost can be obtained.

Furthermore, since it is not necessary to carry out the pressing process when manufacturing the module of the battery main body, the number of days required for all the processes can be shortened and the production efficiency can be improved.

[Brief description of drawings]

FIG. 1 is a plan view showing a configuration of a separator plate and a bolt tightening portion to which a method for manufacturing a zinc-bromine battery according to the present invention is applied.

FIG. 2 is a graph showing the results of surface pressure measurement at the portions A to H and K to Q of the separator plate of FIG.

FIG. 3 shows the results of conducting a seal test on a battery body.

FIG. 4 is a graph showing the correlation between the creep amount of a separator and time.

FIG. 5 is an enlarged cross-sectional view of an interface portion between an intermediate electrode and a separator plate after circulating hot water.

FIG. 6 is a graph showing the correlation between the holding pressure of air on the battery body and the standing time.

FIG. 7 is a plan view showing an example of an apparatus for conducting a preliminary experiment of the present invention.

8 is a side sectional view of FIG.

FIG. 9 is an exploded perspective view showing the structure of a zinc-bromine battery body.

FIG. 10 is a schematic diagram showing the operating principle of a zinc-bromine battery.

FIG. 11 is a schematic diagram showing a module structure of a battery main body in which each component is assembled.

FIG. 12 is a left side view of FIG.

FIG. 13 is a plan view showing the configuration of a separator plate.

14 is a sectional view taken along the line AA of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Intermediate electrode 2 ... Separator plate 3 ... Separator 8 ... Clamping end plate 9 ... Laminated end plate 10 ... Positive electrode manifold 11 ... Negative electrode manifold 12 ... Channel 13 ... Micro channel 14 ... Positive electrode side storage tank 17 ... Negative side storage tank 19 ... Positive side pump 21 ... Negative side pump 22 ... Bolt 23 ... Disc spring 25 ... Rib 27 ... Valve 28 ... Pressure gauge 29 ... Connection jig 30, 31 ... Test piece

Claims (6)

[Claims] 1. A separator plate having ribs provided thereon and an intermediate electrode are stacked to form a single cell, and a plurality of the single cells are laminated to form a battery main body, and a current collecting mesh is provided at both ends of the battery main body. A current collecting electrode having the above, a laminated end plate for pressing and a pair of clamping end plates are arranged, and the clamping end plates are integrally laminated and fixed by bolting with a disc spring interposed. In such a zinc-bromine battery, the separator plate, which is a constituent member of the battery main body, and the intermediate electrode are laminated, and the minimum tightening of the bolt is preliminarily performed by an experimental piece using the same constituent material as the separator plate and the intermediate electrode. The force is calculated, and to this minimum tightening force, the creep amount of the constituent material caused by the ambient heat change, the surface pressure required to saturate the creep in a short time, and the area of the rib projecting on the separator plate And the disc spring constant and tightening In addition the number of belt as a factor to determine the final fastening force by calculation, zinc, characterized in that as tightening the bolts of each plurality of evenly diagonally - method for producing bromine battery. 2. The minimum tightening force U is U = (air pressure of 1 atm) × (electrode area + flow channel area) + (rib area) × (minimum surface pressure) ... The method for manufacturing a zinc-bromine battery according to claim 1, wherein the method is calculated by the formula (1). 3. The final tightening force W is W = (surface pressure required to saturate the creep of constituent materials) × (rib area) + (creep amount) × (disc spring constant) × (number of springs) ) .................... characterized by being calculated by the equation (2), The method for producing a zinc-bromine battery according to claim 1. 4. The tightening force of one bolt is tightened so as not to exceed (final tightening force / number of bolts), and finally the tension of all bolts is the above (final tightening force / number of bolts). The method for manufacturing a zinc-bromine battery according to claim 1, 2, or 3, wherein the amount of contraction of the disc spring is adjusted so that 5. A separator plate, which is a constituent member of a battery main body, and an intermediate electrode are laminated, and a minimum tightening force of a bolt is obtained in advance by an experimental piece using the same constituent material as the separator plate and the intermediate electrode. In addition to this minimum tightening force, the amount of creep of the constituent materials caused by ambient heat change, the surface pressure required to saturate the creep in a short time, the area of ribs protruding on the separator plate, and the disc spring constant. And the number of bolts for tightening are added as factors to determine the final tightening force by calculation, and after tightening each bolt evenly diagonally, the tension of all bolts is the above (final tightening force / Volume of bolts), adjust the amount of contraction of the disc spring, circulate hot water in the battery body, then cool it. After draining the water, re-tighten the lowered bolts and tighten all bolts. Is characterized by adjusting And a method for manufacturing a zinc-bromine battery. 6. The tightening force W ′ of the bolt after draining water after the hot water circulation is W ′ = (minimum tightening force) + (disc spring constant) × (thermal expansion / contraction amount) × (number of bolts ) ··············· (3) formula, characterized in that A method for producing the zinc-bromine battery described.