JPH0448635Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an SOC measuring device for a zinc-bromine battery.

The zinc-bromine battery is known as one of the new batteries (for example, the Journal of the Institute of Electrical Engineers of Japan Vol. 103, No. 8-Showa
(August 1958).

[Prior Art] Zinc-bromine batteries have a short history of development compared to lead batteries, and are still at the development stage for practical use. Therefore, it seems that there has been insufficient research into methods for determining the state of charge of batteries, that is, the remaining capacity (SOC), and there have been no reports on this. However, if we were to choose a charging/discharging management method, a method has been implemented in which a rough SOC is estimated by considering an estimated value of the self-discharge amount in the respective integrated values of the charging amount and the discharging amount.

[Problems that the invention aims to solve] Conventional problems However, compared to lead batteries, zinc-bromine batteries have a considerably higher self-discharge amount during charging and discharging and when at rest, and The amount of self-discharge varies greatly depending on the discharge conditions, especially the management (processing) during rest, and it is extremely difficult to estimate the amount of self-discharge accurately.

For example, when an electric vehicle is powered by a zinc-bromine battery, the problem arises that estimating the possible range based on its remaining capacity becomes unreliable.A similar problem arises when using a zinc-bromine battery. This will also occur when used as a stationary device.

In addition, in a zinc-bromine battery, for example, when general constant current charging is performed, the reaction product (Br ₂ ) on the positive electrode side
is stored as a complex in the tank, so the charging voltage is kept almost constant. Therefore, it is impossible to estimate SOC from charging voltage changes, and at the same time
Since the SOC cannot be accurately determined, there is a high possibility of overcharging of the battery, and abnormal electrodeposition of zinc on the negative electrode and gas generation due to a sudden increase in voltage are promoted. ) was a problem.

Purpose of the invention The present invention was devised in view of the above-mentioned conventional problems, and its purpose is to accurately measure the SOC of a zinc-bromine battery based on the amount of bromine complex on the positive electrode side, which changes with the progress of charging and discharging. By doing so,
The objective is to fully draw out the potential of batteries, improve their usability, and further significantly improve battery performance in terms of usage.

[Means and effects for solving the problem] In order to achieve this object, the present invention provides a complex amount measuring means for measuring the bromine complex in a catholyte tank that stores the catholyte of a battery, and a method for measuring the amount of this complex. It has a conversion means for converting the amount of bromine complex obtained by the measurement means into a physical quantity regarding the state of charge, and an SOC display means for displaying the value of SOC, which is the state of charge, based on the physical quantity obtained by the conversion means. , is characterized in that the state of charge of the battery is measured by the amount of bromine complex in the positive electrode solution.

With this configuration, the true nature of zinc-bromine batteries can be realized.
SOC can be measured based on the amount of bromine complex that changes in response to SOC, which also takes into account the amount of self-discharge.

[Embodiments] Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

As shown in FIG. 1, in the positive electrode tank 12 filled with the electrolyte 10, a cylindrical body 14, which is open at the bottom and closed at the top, penetrates the lid of the positive electrode tank 12 and stands upright in a liquid-tight manner. An electrolytic solution inflow/outflow hole 14a is formed above the large diameter portion of the cylindrical body 14.

A gap is provided inside the cylinder 14 so that the float 1
6 is inserted, the cylinder body 14 and the float 16
All the surface parts of the float 16 are made of polyolefin resin or tetrafluoride resin, etc., like the catholyte tank 12, and the specific gravity of the float 16 is a combination of the specific gravity of the aqueous electrolyte 10 and the amount of bromine complex 18, which changes with the progress of charging and discharging. Specific gravity value between 1.8 and 2.0, ideally
The float 16 is adjusted as follows, and the float 16 is displaced up and down following the displacement of the bromine complex liquid level 18a due to a change in the amount of the bromine complex 18.

Further, an iron core 20 is built in the upper part of the float 16 that protrudes above the cathode liquid tank 12, and the cylindrical body 1
A differential transformer 22 as a converter for electrically converting the amount of vertical displacement of the float 16 is installed on the upper outer circumference of the float 16 .

An AC power source 24 is connected to the primary coil of the differential transformer 22, and the displacement of the float 16 in response to a change in the amount of the bromine complex 18 is expressed by the differential transformer 22 as a change in voltage V. Differential transformer 2
The output voltage of No. 2 is input to an indicator 28 via an amplifier 26.

By the way, the experimental results show that the amount of bromine complex 18 and
The relationship between SOC is as shown in the graph of FIG. The relationship in Figure 2
By separately calibrating each charging and discharging process as an SOC value, the SOC of the battery can be directly read from the indicator 28 in both charging and discharging processes.

Incidentally, an electrolyte inflow pipe 30 and an electrolyte outflow pipe 32 are attached to the side surface of the positive electrode liquid tank 12, and a bromine complex outflow pipe 34 is attached to the bottom surface.

In addition, as another embodiment, as shown in FIG. 3 or 4, a sub-tank 36a or 36b for storing the bromine complex 18 is installed inside the catholyte tank 12, and the charging time curve or discharging time curve shown in FIG. By changing the cross-sectional area of the sub-tanks 36a, 36b so that the displacement of a float (not shown) provided in the sub-tanks 30a, 30b is proportional to the SOC, the scale of the indicator 28 can be changed during charging or discharging. It is also possible to have equal intervals at either time.

As for the setting location of the differential transformer as another embodiment, first, as shown in FIG.
There is a method in which the differential transformer 22 is installed on the outer periphery of the cylindrical body 14 that penetrates through and is supported upright and protrudes above the lid 12a. In this case, it is possible to eliminate local protrusions of the positive electrode tank 12. be. Further, as shown in FIG. 6, the cylinder body 14 and the differential transformer 2
There is also a method of integrating the cylindrical body 14 with the cathode liquid tank 12 and supporting it upright within the cathode liquid tank 12. In this case, it has the effect of the above method without complicating the structure of the cathode liquid tank 12, and the SOC The ease of installing the measuring device is improved.

In addition, as a means for measuring the amount of bromine complex, in addition to the liquid level measurement using the float, a means for optically measuring the boundary between the complex and the electrolyte solution, a means for measuring the entire weight of the positive electrode solution including the complex, etc. are used. Those skilled in the art will readily understand that this can be done.

[Effect of the invention] As explained above, according to the invention, zinc-
Since SOC is measured based on the amount of bromine complex that changes in response to the true SOC of a bromine battery, that is, the SOC that also takes into account self-discharge, it is possible to measure SOC with high accuracy, and it is also easy to maintain the battery. This has the effect of enabling efficient management and improving battery performance such as energy density, output density, and lifespan.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing an example of the SOC measuring device for a zinc-bromine battery of the present invention, Figure 2 is a diagram showing the relationship between the amount of bromine complex, and Figures 3 and 4 are diagrams showing the relationship between the displacement of the float and the SOC. Explanatory diagram showing another embodiment in which a sub-tank for bromine complex is provided for proportionalizing the
This figure and FIG. 6 are explanatory diagrams showing still another embodiment in which the installation location of the differential transformer is changed. 10...Aqueous electrolyte, 12...Positive electrolyte tank,
14... Cylindrical body, 16... Float, 18... Bromine complex, 22... Differential transformer, 28... Indicator.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A complex amount measuring means for measuring bromine complexes in a catholyte tank that stores the catholyte of a battery, and the amount of bromine complexes obtained by this complex amount measuring means regarding the state of charge. a conversion means for converting the physical quantity into a physical quantity; and an SOC display means for displaying the SOC value in the state of charge based on the physical quantity obtained by the conversion means, A zinc-bromine battery SOC measuring device characterized by measuring the state of charge of a zinc-bromine battery. (2) Utility Model Registration In the device according to claim 1, the complex amount measuring means is provided in the positive electrode liquid tank and is displaced in the vertical direction following the displacement of the bromine complex liquid level due to a change in the bromine complex amount. A zinc-bromine battery characterized by being a float that
SOC measuring device. (3) Utility Model Registration The device according to claim 2, wherein the converting means is a converter that converts the displacement of the float into an electrical change. (4) Utility model registration Claim 3: The SOC measuring device for a zinc-bromine battery, wherein the converter is a differential transformer. (5) The device according to any one of claims 2 to 4 for utility model registration, characterized in that the specific gravity of the float is between the specific gravity of the aqueous electrolyte and the specific gravity of the bromine complex. SOC measuring device for zinc-bromine batteries.