CN103233141B

CN103233141B - High-strength corrosion-resistant thin-wall battery zinc cylinder and manufacturing method thereof

Info

Publication number: CN103233141B
Application number: CN201210528768.7A
Authority: CN
Inventors: 忻吉良; 史定武
Original assignee: Ningbo Guanghua Battery Co ltd
Current assignee: Ningbo Guanghua Battery Co ltd
Priority date: 2012-12-06
Filing date: 2012-12-06
Publication date: 2016-03-30
Anticipated expiration: 2032-12-06
Also published as: CN103233141A

Abstract

The invention discloses a high-strength corrosion-resistant thin-wall battery zinc cylinder, which is characterized in that the zinc alloy forming the zinc cylinder comprises the following components in percentage by weight: 0.001 to 0.003 percent of magnesium, 0.003 to 0.010 percent of titanium, 0.001 to 0.010 percent of aluminum, 0 to 0.010 percent of indium, 0 to 0.150 percent of lead, 0 to 0.002 percent of cadmium and the balance of zinc and inevitable impurities brought by raw materials; wherein the total content of inevitable impurities is less than 0.010%, and the inevitable impurities comprise less than or equal to 0.003% of iron, less than or equal to 0.001% of copper and less than or equal to 0.001% of tin. The preparation method comprises the following steps: melting the metal at 450 to 550 ℃; crystallizing the mixture into a zinc thick plate in a caster at the cooling speed of between 50 and 70 ℃/second at the temperature of between 430 and 480 ℃; rolling and rolling the mixture into a zinc sheet under the temperature of 150 to 220 ℃; punching the mixture into a battery zinc cake at 25 to 120 ℃; and carrying out backward extrusion at 25-120 ℃ to obtain the thin-wall battery zinc cylinder. The zinc can has good mechanical strength, corrosion resistance and discharge characteristic when the wall thickness is reduced by 20 to 40 percent, so that zinc resources are saved, the production cost of the battery is effectively reduced, and the environment protection is facilitated.

Description

High-strength corrosion-resistant thin-wall battery zinc cylinder and manufacturing method thereof

Technical Field

The invention relates to a cathode material of a zinc-manganese battery, in particular to a high-strength corrosion-resistant thin-wall battery zinc cylinder and a manufacturing method thereof.

Background

The zinc can of the battery is a common cathode material of the zinc-manganese battery. It is both the active material for the electrode reaction in the battery and the container of the battery. When the electrolyte is contacted with the electrolyte, the electric quantity is rapidly supplied, the zinc is gradually consumed, so that the zinc cylinder becomes thin, and the zinc cylinder can generate self-corrosion during the storage of the battery, so that the capacity of the battery is reduced, the electrical property of the battery is deteriorated, and perforation can be caused when the battery is serious. The zinc cylinder is subjected to rolling, punching, extruding and the like in the manufacturing process. Therefore, the zinc can material should have good plastic processing performance, proper mechanical strength and better corrosion resistance, and can maintain high electrochemical performance of the zinc can. These characteristics are mainly related to the composition of the zinc-based alloy, and secondly to the manufacturing processes, such as melting, casting, rolling, punching, extrusion, various temperatures and speeds, as well as the processing ratios, the precision of the equipment, etc. In order to ensure the mechanical strength, the corrosion resistance and the discharge characteristic of the zinc-manganese battery, the wall thickness of the zinc cylinder of the conventional battery is required to be 0.25 to 0.35mm, the deformation resistance strength of the zinc cylinder is 2.5 to 4.0kg/f, and the Brinell hardness of a zinc cake for preparing the zinc cylinder is HB38 to 45 degrees. In fact, after the zinc-manganese battery is completely discharged, the consumption of zinc in the zinc cylinder is generally 25 to 30 percent, namely, the wall thickness of the zinc cylinder is reduced by about 25 to 30 percent, and the rest most of zinc resources are used for the mechanical strength and corrosion resistance of the zinc-manganese battery and are discarded as waste. In order to save zinc resources, injection-molded zinc can batteries, i.e. plastic is used to replace part of zinc, so as to save zinc resources, have been studied. However, the mechanical strength of the zinc can of the plastic battery is reduced, and the manufacturing process and the production cost of the zinc can are increased, so that the application and the popularization of the zinc can in the actual production are not achieved.

Disclosure of Invention

The invention aims to provide a high-strength corrosion-resistant thin-wall battery zinc can, so that the mechanical strength, corrosion resistance and electrical property equivalent to those of the zinc can in the prior art can be still maintained under the condition that the wall thickness of the zinc can is remarkably reduced compared with that of the conventional zinc can. The invention aims to solve another technical problem of providing a manufacturing method of a thin-wall battery zinc cylinder with high strength and corrosion resistance.

The invention relates to a high-strength corrosion-resistant thin-wall battery zinc cylinder, which comprises the following zinc alloy components in percentage by weight: 0.001 to 0.003 percent of magnesium, 0.003 to 0.010 percent of titanium, 0.001 to 0.010 percent of aluminum, 0 to 0.010 percent of indium, 0 to 0.150 percent of lead, 0 to 0.002 percent of cadmium, and the balance of zinc and inevitable impurities brought by raw materials; wherein the total content of inevitable impurities is less than 0.010%, and the inevitable impurities comprise less than or equal to 0.003% of iron, less than or equal to 0.001% of copper and less than or equal to 0.001% of tin.

The grain size of the battery zinc cake made of the zinc alloy is 0.10-10um.

The Brinell hardness of the battery zinc cake made of the zinc alloy is HB 42-50 degrees.

The wall thickness of the zinc cylinder is 0.12 to 0.24mm, and the deformation resistance strength is 2.5 to 4.0kg/f.

The method for preparing the high-strength corrosion-resistant thin-wall battery zinc cylinder comprises the following steps:

(1) Completely melting a zinc ingot in a zinc melting furnace at 450 to 550 ℃, adding alloy composition elements such as magnesium, titanium and aluminum, and uniformly melting;

(2) The casting temperature is 430 to 480 ℃, and the zinc thick plate is crystallized in a wheel casting machine at the cooling speed of 50 to 70 ℃/second;

(3) Rolling and rolling the mixture into a zinc sheet at the temperature of 150 to 220 ℃;

(4) Punching the mixture into a battery zinc cake at the temperature of 25 to 120 ℃;

(5) And carrying out backward extrusion at 25-120 ℃ to obtain the thin-wall battery zinc cylinder.

The titanium is added into the zinc melting furnace in the form of zinc-titanium alloy.

The zinc-titanium alloy is a zinc-titanium alloy containing 1-5% of titanium by weight.

The idea of the invention is as follows: the mechanical strength, hardness and corrosion resistance of the battery zinc cylinder are obviously improved, so that the wall thickness of the zinc cylinder can be greatly reduced, the consumption of zinc resources is reduced, and the influence of battery wastes on the environment can be reduced.

Based on the above invention idea, the inventor of the present invention has intensively studied a technical route for improving the mechanical strength of the zinc can, and has taken corrosion resistance and electrical properties into consideration, and found that adding a proper amount of metal elements with a melting point higher than that of zinc into the zinc can material has the effects of improving the hardness of the zinc cake and the deformation resistance of the zinc can. Such as calcium, magnesium, titanium, manganese, iron, nickel, aluminum, and the like. The metal elements are preferentially combined with zinc in a solid solution during the casting crystallization of the zinc alloy to form fine crystals, and the faster the cooling speed of the zinc crystals is, the more fine crystals are formed during the crystallization process. Meanwhile, in the research, the formed fine crystals are rolled under the condition of controlling the recrystallization temperature, so that the combination among crystal grains is more compact, and the hardness, the toughness and the deformation resistance of the zinc cylinder can be effectively enhanced.

The other problem to be solved of the thin-wall battery zinc cylinder is corrosion resistance, and although the corrosion resistance of the zinc cylinder is improved by fine crystal grains and strict crystal spacing, the performance difference and the content of metal elements added into the zinc cylinder are related to the corrosion performance of zinc. The inventor researches and discovers that metal elements with a positive potential compared with zinc and zinc are sintered to generate self-discharge in the storage process of the battery, local corrosion points generate gas, and the gas can cause ballooning and even perforation and leakage of the battery, and the self-discharge phenomenon is more serious when the content of impurity metal with the positive potential compared with the zinc is more. Meanwhile, it is found that the metal element with the potential more negative than that of zinc also has galvanic current in the contact surface with the medium, because the metal element with the potential more negative than that of zinc is melted first. If these metal elements melted first form a passivation film on zinc, further corrosion of zinc is suppressed. The protective film has a self-healing repairing function on local corrosion points of the zinc cylinder.

In the research, the metal elements added into the zinc cylinder also have the characteristic of high hydrogen evolution potential, and the metal elements with high hydrogen evolution potential are distributed in the crystal gaps of zinc crystals. When the battery is stored or discharged, the hydrogen evolution reaction can be reduced, the hydrogen depolarization corrosion of the zinc cylinder can be reduced, and the influence of hydrogen expansion on the mechanical strength of the zinc cylinder can be prevented.

On the basis that the existing battery technology is not changed (the technology is not changed, namely the basic technological process is not changed, and the processing temperature, the cooling speed and the like are not included), the invention not only saves the zinc resource, but also more effectively reduces the production cost of the battery and plays a great role in environmental protection. Tests show that the thin-wall zinc can still maintain the mechanical strength, corrosion resistance and discharge characteristic effects which can be achieved by the zinc can in the prior art when the thickness of the thin-wall zinc can is reduced by 20 to 40 percent compared with the thickness of the conventional zinc can wall.

Detailed Description

The present invention will be further illustrated by the following examples.

In the examples, the R6 zn-mn cell can was used as a sample, but the invention is not limited to other thin-walled cans.

According to the production sequence of the battery zinc cylinder in the prior art, the battery zinc cake is firstly manufactured and then extruded into the battery zinc cylinder, so that the hardness and the corrosion resistance of the battery zinc cake indirectly reflect the deformation resistance and the corrosion resistance of the battery zinc cylinder and indirectly determine the discharge storage performance of the zinc-manganese battery.

Unless otherwise specified, the total content of inevitable impurities derived from the raw materials in the examples of the present invention is 0.010% or less, and the alloy compositions in the examples and comparative examples are in weight percent.

Example 1

The examples in this group examine the change in hardness and corrosion resistance of zinc cakes obtained by adding a metal having a higher melting point than zinc and a negative potential than zinc, such as magnesium, titanium or aluminum, to zinc, and the Brinell hardness measurement method of zinc cakes is specified by CTB 231. The corrosion resistance of the zinc cake is that the zinc cake is cleaned, dried and weighed, then the zinc cake is put into 10% dilute hydrochloric acid solution to be soaked for 1 hour, and then the zinc cake is cleaned, dried, cooled and weighed, and the corrosion weight loss rate is calculated.

The preparation method of the zinc cake comprises the following steps: high-grade 0# zinc ingot is selected, and the raw materials of zinc are controlled to be less than 0.001% of iron, less than 0.001% of copper, less than 0.001% of tin, less than 0.002% of cadmium and less than 0.003% of lead. And (3) putting the zinc ingot into a zinc melting furnace, heating to 480-550 ℃ to completely melt, and then respectively adding magnesium, titanium (titanium-zinc alloy containing 1wt% of titanium) and aluminum metal elements. The zinc cake is manufactured by the conventional process, and the Brinell hardness and the corrosion weight loss rate of the zinc cake are shown in the table 1.

TABLE 1

The melting point of magnesium is higher than that of zinc, is 650 ℃, has the standard potential of-2.37V and is lower than that of zinc, and the magnesium and the zinc are close-packed hexagonal crystals and are easy to form a brittle compound structure after being co-melted with the zinc. As can be seen from the data in table 1, the addition of a trace amount of magnesium significantly improves the mechanical strength and hardness of the zinc cake, and when the magnesium content is more than 0.003%, the hardness is too high and the corrosion rate increases.

Titanium is a high-melting-point metal, a titanium-zinc alloy containing 1wt% of titanium is prepared firstly and then added into zinc liquid, the standard potential of the titanium is-1.63V, the standard potential is lower than that of the zinc, hexagonal crystals are densely arranged, and the titanium and the zinc are easy to be co-melted. Titanium also has the characteristics of high hydrogen evolution potential and easy formation of a passivation protective film. The addition of a small amount of titanium to the zinc increases the strength and hardness of the zinc cake, as well as the corrosion resistance, and the hardness becomes too high when the titanium content is greater than 0.015%.

The melting point of the aluminum is 660 ℃, the standard potential is-1.70V, the aluminum is lower than zinc, the aluminum belongs to a face-centered cubic crystal, the aluminum can improve the fluidity of zinc liquid, and a passivation protective film is easy to form. The addition of aluminum also increases the hardness and corrosion resistance of the zinc cake, and when the aluminum content is too high, the discharge performance of the battery may be affected.

Example 2:

in this group of examples, changes in the hardness and corrosion resistance of zinc cakes were examined by adding an impurity metal element having a positive potential compared with zinc, such as iron, copper, tin, etc., to zinc, as shown in Table 2. The brinell hardness and corrosion resistance were measured as in example 1.

TABLE 2

As can be seen from Table 2, when Fe is 0.010% or more, cu is 0.002% or more, and Sn is 0.002% or more, the corrosion resistance of the zinc cake is deteriorated and the requirement for the thin-wall zinc cylinder is not satisfied.

Example 3

In this group of examples, changes in the hardness and corrosion resistance of zinc cakes were examined by adding metals having high hydrogen evolution potentials, such as lead, cadmium, and indium, to zinc, as shown in table 3.

TABLE 3

Lead, cadmium and indium have melting points lower than that of zinc, and are generally present between zinc grain boundaries during crystallization, and corrosion often starts from the zinc grain boundaries, thereby effectively suppressing corrosion of zinc.

When the addition amounts of lead, cadmium and indium are increased, the corrosion resistance is improved. Since the lead and cadmium in the battery have a serious influence on the environment, the low concentration content must be limited. Indium is a rare metal, and the price is high, and should be controlled as much as possible, and the addition is less.

Example 4

The group of examples inspects the influence of the processing temperature on the grain boundary of zinc grains and the change condition of the hardness and the corrosion resistance during the manufacturing process of the zinc cake and the zinc cylinder

The preferred combination of zinc alloys is: 0.0015 percent of magnesium, 0.005 percent of titanium, 0.003 percent of aluminum, 0.005 percent of indium, less than or equal to 0.003 percent of lead, less than or equal to 0.002 percent of cadmium, less than or equal to 0.003 percent of iron, less than or equal to 0.001 percent of copper and less than or equal to 0.001 percent of tin. The composite zinc alloy is melted uniformly at 480-550 ℃, the zinc alloy is easy to segregate when the melting temperature is lower than 450 ℃, the components are not uniform, the crystal grains are large, the oxidizability is increased when the melting temperature is higher than 550 ℃, and slag is easy to be included in the zinc liquid.

The casting temperature is controlled to be 430-480 ℃, the uniform fluidity of the zinc liquid can be ensured, the air suction and oxide impurities are reduced, when the casting temperature is lower than 430 ℃, the fluidity of the zinc liquid is poor, and when the casting temperature is higher than 480 ℃, the zinc liquid is easy to suck air and clamp slag. The cooling rate of the molten zinc during casting directly affects the grain size and crystal arrangement of the zinc alloy, and the effect of the cooling rate on the grain hardness and corrosion resistance during crystallization in a caster is shown in table 4.

TABLE 4

Table 4 shows that the crystal grain size of the zinc alloy increases and the hardness and corrosion resistance decrease when the casting cooling rate is less than 50 ℃/sec, but when the cooling rate is more than 70 ℃/sec or more, the crystal grain size of the zinc alloy becomes finer but the corrosion resistance decreases, and it is likely that the metal element having a low melting point and a high hydrogen evolution potential in the zinc grain boundary is affected by rapid crystallization. But corrosion resistance has a limited impact.

The ductility of the zinc thick plate is best when the rolling temperature is controlled to be 150-220 ℃, so that the zinc grains are tightly compacted. The zinc plate is easy to peel and crack when the temperature is lower than 150 ℃ and easy to crack when the temperature is higher than 220 ℃.

The punching temperature of the zinc cake is 25-120 ℃, so that the smoothness of a cut of the zinc cake can be ensured, otherwise, the increase of burrs is easy to cause, and the cut is rough.

Example 5 to example 16

The manufacturing method and the steps of the thin-wall battery zinc cylinder are as follows:

Wherein the titanium is added into a zinc melting furnace in the form of zinc-titanium alloy, and the zinc-titanium alloy contains 1-5 percent of titanium by weight.

The method for measuring the deformation resistance strength of the thin-wall battery zinc cylinder comprises the following steps: the zinc cylinder is arranged on the base of the triangular groove, and certain pressure is applied in a point manner at a position 10mm away from the opening of the zinc cylinder. The deformation resistance strength is obtained when the zinc cylinder is just deformed. The corrosion resistance of the zinc cylinder is measured by the same method as the zinc cake of the battery, and the content which is not related in the embodiment is the same as the prior art.

The wall thickness and the content of each component of the thin-walled zinc can in each example were varied, and the deformation resistance and corrosion resistance to the zinc can are shown in Table 5

Comparative example 1 to comparative example 3: the conventional battery zinc tube added with lead and cadmium adopts the conventional process technology, and the wall thickness of the zinc tube is respectively R6:0.25mm, R03:0.25mm, R12:0.30mm.

As can be seen from table 5, the thin-walled battery zinc cans of examples 5 to 16 provided by the present invention have the same effects of deformation resistance and corrosion resistance as the conventional battery zinc cans of comparative examples 1 to 3.

Claims

1. A high-strength corrosion-resistant thin-wall battery zinc can is characterized in that the zinc alloy forming the zinc can comprises the following components in percentage by weight: more than 0.0015 percent and less than or equal to 0.003 percent of magnesium, 0.003 to 0.010 percent of titanium, 0.001 to 0.010 percent of aluminum, 0 to 0.010 percent of indium, 0 to 0.150 percent of lead, 0 to 0.002 percent of cadmium and the balance of zinc and inevitable impurities brought by raw materials; wherein the total content of inevitable impurities is less than 0.010%, and the inevitable impurities comprise less than or equal to 0.003% of iron, less than or equal to 0.001% of copper and less than or equal to 0.001% of tin.

2. The zinc can of claim 1, wherein said zinc alloy is formed into a zinc cake having a grain size of 0.10 to 10 μm.

3. The battery zinc can of claim 1 or 2, characterized in that the brinell hardness of the battery zinc cake made of zinc alloy is HB42 to 50 degrees.

4. The zinc can for battery according to claim 1 or 2, characterized in that the thickness of the zinc can is 0.12 to 0.24mm and the deformation resistance strength is 2.5 to 4.0kg/f.

5. A method of making the high strength, corrosion resistant thin wall battery can of claim 1, comprising the steps of:

(1) Completely melting a zinc ingot in a zinc melting furnace at 450-550 ℃, adding alloy composition elements of the zinc cylinder, and uniformly melting;

(2) The casting temperature is 430-480 ℃, and the zinc plate is crystallized in a wheel casting machine at the cooling speed of 50-70 ℃/s;

(3) Rolling and rolling the mixture into a zinc sheet at the temperature of between 150 and 220 ℃;

(4) Punching the mixture into a battery zinc cake at the temperature of between 25 and 120 ℃;

(5) And performing backward extrusion at 25-120 ℃ to obtain the thin-wall battery zinc cylinder.

6. The method according to claim 5, characterized in that said titanium is introduced into said furnace in the form of a zinc-titanium alloy.

7. A method according to claim 6, characterized in that said zinc-titanium alloy is a zinc-titanium alloy containing 1-5% titanium in weight percent.