KR810000253Y1 - Battery having mask which electrochemically inactivates limited surface of metalic component - Google Patents

Abstract

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Description

Battery with corrosion mask

1 is an external view of a battery constituting the present invention.

2 is a sectional view taken along the line A-A of FIG.

3 to 5 are cross-sectional views showing an embodiment of the present invention.

The present invention relates to a battery having a corrosion protection mask, and more particularly to a battery having a mask that electrochemically deactivates a limited surface of a metal component to prevent undesirable local corrosion of electrodes or terminals.

In general, the metal parts of the battery form an outer surface which is not in contact with the inner surface which contacts the electrolyte, and the inner surface of these metal parts are locally corroded by the electrochemical reaction in the active charge and discharge of the battery, thus reducing the capacity and leaving the battery. Problems such as shortening of life and leakage of electrolyte may occur. This local corrosion occurs irregularly anywhere on the surface of the electrode, and experience shows that the corrosion occurs in the electrical contact with the outer surface of the electrode or in contact with air.

In order to reduce or eliminate such irregular corrosion, various corrosion inhibitors have been applied to the zinc electrode surface of the battery, and the reaction rate, in particular, has been reduced during the leaving of the battery. For example, US Pat. An adhesive film was used to dissolve, disintegrate, disintegrate, or otherwise act upon.

As a result, local corrosion of the battery due to the forming process and the hot soldering can be avoided. In addition, in US Patent Nos. 2,279,575 and 2,343,194, wood balsams and CrO ₃ groups were added to the exposed surface of the zinc electrode to prevent corrosion during the inactive period of the battery, and to improve the lifetime and electrolyte leakage. .

In all of the above conventional techniques, the corrosion inhibitor is applied to the entire electrochemically active surface of the zinc electrode, and the battery life is reliably obtained, but this is obtained at a slight sacrifice of the discharge rate during the active discharge of the battery.

On the other hand, undesirable local corrosion sometimes occurs in the area of the metal parts with which the electrical connection is made. This corrosion problem is particularly a problem when the contact is caused by pressure or adhesion to maintain a good connection or when the connection is made of heat.

That is, heat changes the grain structure in the vicinity of the metal to which it is electrically connected, and makes sensitive corrosion undesirable.

This problem is due not only to the heat from the lead dams, but also to the heterogeneity of the connected metal parts (eg zinc) and the brazing metals (eg lead and tin). The problem of corrosion is that the thinner the thickness of the metal component, the greater the possibility of corrosion and accompanying it, which is one of the major constraints in thinning the metal parts and batteries. In other words, increasing the thickness of the metal to overcome the corrosion problem increases the thickness of the battery and / or decreases the capacity, increases the price, and the electrochemical effect of the battery electrode as a metal part (for example, a zinc electrode). This results in a decrease. Another important aspect in battery design and manufacturing is to make electrical connections outside the battery after the battery assembly process is complete.

In the prior art, the electrochemically active surface of the zinc anode is soldered, and an electrically insulating adhesive is applied to the solder joint to prevent the battery from being electrochemically caused by the application. (See US Patent No. 2,870,235). However, in such a hole, the lead dam connection and the application of the adhesive are made before the zinc electrode is assembled into the battery, and the problem of soldering to the outside of the assembled battery is not solved. Further, in US Pat. No. 2,870,235, the solder joint and the application portion of the adhesive are in contact with the battery electrolyte appearing on the surface of the zinc electrode.

In some battery designs, even if no electrical connection is made to the metal surface as a final step in the assembly of the finished battery, the metal part has an outer surface in which all or part of it is blown into the air.

It is important that this external surface be partially exposed, and that the battery be assembled so that the electrical connection is made when it is used for a long period of time so that undesired corrosion does not occur during the battery leaving period.

This reduces or eliminates undesirable corrosion and allows the use of thin metal parts for economical use, electrical connections, especially heat connections, and pre-assembled, eliminating the effects of particulate composition and the harmful effects of foreign metals. There has been a need for local corrosion protection means that electrical connections are made to the exterior of the battery and thus satisfying various conditions simultaneously, such as protecting metal areas exposed to air over long periods of time.

In view of the above, the present invention provides an electrode or terminal material having an inner surface in contact with an electrolyte and an outer surface not in contact with the electrolyte, that is, providing an undesirable local corrosion prevention means for the battery metal part. A mask is formed on an inner surface of a portion of the.

When the metal part is an electrode, the mask can prevent local corrosion without reducing the electrochemical activity at the remaining electrode surface. Therefore, the discharge rate of the battery is not reduced by the corrosion preventing means. In order to compensate for the loss of electrochemical activity on the surface of the electrode, the mask may be made of a metal or a metal compound having a chemical composition compatible with the electrode.

In addition, since the present invention can prevent undesirable corrosion, very thin metal foil can be used since the thickness of the spare part is not required in the metal thickness of the battery component.

Furthermore, since a mask is formed on the inner surface of the electrode or terminal portion on which the electrical connection is made, the mask prevents the metal from being electrochemically sensitive to heat and / or foreign matter when making and maintaining the electrical connection. .

By this mask, electrical connection can be made with respect to the assembled battery outer part than the parts to be assembled later and the parts inside the battery.

In addition, the mask prevents corrosion of the components exposed to the air on the outer surface of the metal part, whereby the electrical connection can be easily performed even after the battery is left in an inactive state for a long time.

Preferably, the metal part is a negative electrode of the battery, and the electrode is preferably metal foil of zinc, lead, magnesium, aluminum, or an alloy thereof.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is an external view of a battery constituting the present invention, a cross-sectional view taken along line A-A is shown in FIG. 2, and the thickness of the material is enlarged for explanation. The battery is provided with an anode 10 made of a thin metal foil of zinc or other metal, a cathode 12 and an electrolyte layer 14 containing an electrolyte therebetween. The conductive plastic layer 16 is disposed on the side of the cathode 12 opposite to the anode 10, and seals the anode with an insulating adhesive 18 around the battery and insulates from the anode. It is.

The outer surface of the anode is exposed to air and acts as a negative terminal of the battery. Also shown in FIG. 2 is a mask 20 coated on a portion of the electrochemically active surface 22 of the anode 10 (ie the surface of the anode in contact with the cathode 12 and the electrolyte layer 14 containing the electrolyte solution). Is shown. The surface of the anode covered by the mask 20 is electrically inactive. On the anode outer surface 24 opposite to the mask 20, an electrical connection line 26 is connected to the anode 10 by soldering connections 28. The mask 20 is also attached to the anode 10 before the anode 10 is assembled with the cathode 12, the electrolytic layer 14, the plastic layer 16 and the adhesive 18. And the electrical connection line 26 can be soldered to the thin metal foil of the battery so that undesirable metal corrosion does not occur in the solder connection region.

The mask 20 shown in FIG. 2 is adhered to the anode 10 by an antistatic adhesive, such as a heat soluble adhesive of polyamide, which may be made of a plastic film (e. G. In the embodiment, a suitable pressure-sensitive plastic film and adhesive tape may be used.

Another configuration of the anode and mask is shown in FIG. On the outer surface of the non-electrically active anode 10 is a non-conductive plastic layer 30 which is electrically insulated from the anode 10 and at the same time corrosion resistant. Outside the anode 10 is provided with a hole 32 in the plastic 30 for electrical contact, which also exposes the outer surface 24 of the anode 10 to ambient air. In order to prevent undesired corrosion in the area of the hole 32, the mask 34 is disposed at the position of the electrochemically active surface 22 opposite the hole 32.

The mask 34 is made of a conductive, thermally soluble adhesive to prevent loss of the electrochemically active surface area in the anode 10 applied by the mask 34, so that the hot melt adhesive is compatible with the anode. It can contain powders of metals and metal compounds that can be used.

In addition to providing an electrochemically active material, this powder imparts an electrochemically similar surface to the anode 10 itself near the boundary between the mask 34 and the anode 10 and around the boundary. Reduces the tendency to corrode (If the battery parts are electrochemically heterogeneous, they sometimes corrode.)

4 shows another configuration of the anode 10 and the mask. An electrical connection line 26 is shown connected to the outer surface 24 of the anode 10 by a pressure sensitive adhesive 36, which adhesive 36 is used without heating, which increases corrosion failure with respect to the metal anode. do. The electrochemically active surface 22 of the anode 10 is provided with a mask 20 which is applied by a separate metal foil 38 of the same type as the anode 10. Like the powder contained in the mask 34 shown in FIG. 3, the metal foil 38 shown in FIG. 4 additionally creates an electrochemically active surface area to increase the capacity of the battery, and The electrochemical heterogeneity at the boundary between the anodes 20 is reduced.

5 shows a variation of the battery shown in FIGS. 1 and 2, wherein the anode terminal 40 is made of a metal foil such as steel, zinc or lead, the inner surface of which is in contact with the internal parts of the battery and The outer surface is exposed to air. The anode 10 is in contact with the inner surface of the anode terminal 40 and is made from particles of a metal active material supported by a binder matrix or attached by flame spinning, vacuum deposition, or other processes.

Within the opening of the anode 10, there is also a mask 20 such as the mask 20 shown in FIG. 2, and the mask 20 is attached to the inner surface of the anode 40. As shown in FIG. In addition, as shown in the drawing, the cathode 12 and the electrolyte layer 14 including the electrolyte solution between the cathode 12 and the anode 10 are disposed below the conductive plastic layer 16 and the anode wood 10. It is disposed on the side of the cathode 12 opposite to and electrically insulated from the anode 40 by the adhesive 18 introduced into the extension of the electrolytic layer 14. On the outer surface of the anode terminal 40, an electrical connection line 26 is connected to the terminal 40 by a solder connection 28. In the configuration of FIG. 5, the inner surface of the anode terminal 40 is in contact with the electrolyte diffused into the anode 10, the cathode 12, and the electrolyte layer 14, and the mask 20 contacts the mask 20. To prevent undesired corrosion in the area of the terminal 40 applied.

Although not shown in FIG. 5, the material particles of the anode 10 extend over the mask 20 to prevent openings or discontinuities in the anode.

The metal parts to which the mask is attached are selected from a wide range of metals, the specific metals for a particular battery design are selected due to the electrochemical system of the battery, and the metal parts serve as electrodes or as terminals. Or based on whether they act as both. For example, when used as an electrode, metal parts are zinc in electrochemical systems used as anode materials, lead in computational systems, manganese dioxide, cuprous chloride, magnesium chloride in combination with silver chloride or cathode and Aluminum combined with manganese may be used. When used as a terminal and the inner surface of the terminal is not the anode of the battery, the metal part can be selected from a wide range of distilled metals in which no electrochemical reaction occurs.

The present invention is a battery having a metal part such that the inner surface is in contact with an electrolyte and partially coated by a mask, but is not limited thereto.

Moreover, this invention is not limited to a specific shape, It can be used also in flat battery and cylindrical battery design.

The specific form shown in FIGS. 2 to 5 is only an example, and is not limited to this.

Claims (1)

In a battery having a metal part whose inner surface is in contact with a battery electrolyte and whose outer surface is not in contact with the electrolyte, a mask 20 is formed on a part of the inner surface of the metal parts 10, 12, 40, and 16. The outer surface of the metal part opposite to 20) is exposed to air to enable the electrical connection 28, so that a part of the interior coated by the mask 20 is electrochemically inactive. Battery with.