JP2004355954A - Disposal method of waste battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive, safe and simple disposal method of a waste battery in which a waste battery is made harmless and generation of heat or ignition can be prevented without requiring a troublesome individual disposal or large energy in the decomposition disposal of a waste battery such as a lithium ion secondary battery. <P>SOLUTION: The waste battery 1 having the electrode parts 1a, 1b exposed is embedded in a conductive granulated body 3 such as graphite and activated carbon filled in a discharge container 2 and is made to discharge applying a pressure on the conductive granulated body 3 as it is or by a movable lid 4. It is desirable that the electric resistance of the conductive granulated body 3 is 1 kΩ cm or less with the pressure of 10 kPa or more applied, and it is desirable that the pressure applied on the conductive granule is 10-1,000 kPa. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a processing method for recycling a waste battery such as a used lithium ion secondary battery.
[0002]
[Prior art]
At present, secondary batteries such as nickel-cadmium batteries, nickel-hydrogen batteries, and lithium-ion batteries are widely used as power sources for portable devices. These secondary batteries have a limited life, and it is desired to recover various valuable metals from used secondary batteries.
[0003]
When recovering various valuable metals from waste batteries such as used secondary batteries, generally, the waste batteries are crushed and dismantled, and sorted to collect valuable metals. However, at the time of this crushing, the crushed material generates heat due to charging energy, and there is a possibility that combustible materials in the battery may ignite. For this reason, how to detoxify the charged waste battery so as not to generate heat and fire during the disassembly process has been a major problem.
[0004]
In particular, a lithium ion secondary battery has a high stored energy in the battery, and when disassembled in a charged state, the organic solvent as an electrolytic solution generates heat and is ignited by the charging energy, resulting in a dangerous state. For this reason, it has been practiced to discharge the charging energy before the dismantling process or to keep the temperature low during the dismantling process to prevent ignition.
[0005]
As a specific processing method, Japanese Patent Application Laid-Open No. Hei 10-241748 proposes a method of extracting an electrolytic solution or a solvent thereof from a battery. Also, JP-A-10-241748, JP-A-11-167936, and Table 00/019557 propose a method of disassembling a battery in a cooled state or under a low temperature of freezing of an electrolytic solution. . Further, Japanese Patent Application Laid-Open No. H10-330855 proposes a method for roasting a battery that does not require detoxification, although the recovery rate of valuable metals is reduced.
[0006]
However, in the method of extracting the electrolyte or the like, there is a problem that the batteries have to be processed one by one in a fine operation, which is very troublesome. In addition, in the method of disassembly by cooling or freezing, it is necessary to use expensive liquid nitrogen or the like in order to maintain extremely low temperature, or to provide a low-temperature refrigeration facility, which requires extra energy and equipment costs. Furthermore, in the method of roasting a battery, there are problems that the recovery rate of valuable metals decreases, a large amount of energy is required to maintain the roasting temperature, and a large amount of exhaust gas needs to be treated. .
[0007]
[Patent Document 1]
JP-A-10-241748 [Patent Document 2]
JP-A-11-167936 [Patent Document 3]
JP-A-00 / 019557 [Patent Document 4]
JP 10-330855 A
[Problems to be solved by the invention]
In view of such a conventional situation, the present invention does not require complicated individual processing, and requires a large amount of energy and equipment cost when dismantling a used waste battery represented by a lithium ion secondary battery. It is an object of the present invention to provide an inexpensive, safe and simple method of treating a waste battery, which can make the waste battery harmless and prevent heat and ignition.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a method for treating a waste battery provided by the present invention includes, before dismantling the waste battery, embedding the waste battery with the electrode portion exposed in the conductive particles filled in the discharge vessel, The discharge is performed as it is or while applying pressure to the conductive powder.
[0010]
In the method for treating a waste battery according to the present invention, the electric resistance of the conductive powder may be 10 kΩ · cm or more when no pressure is applied and 10 kΩ · cm or less when pressure is applied. preferable. In particular, the electric resistance of the conductive powder is preferably 1 kΩ · cm or less under a pressure of 10 kPa or more.
[0011]
In the method for treating a waste battery according to the present invention, it is preferable that the conductive powder is a powder mainly containing at least one selected from graphite, activated carbon, coal, and coke. Further, by adjusting the pressure applied to the conductive particles, the time required for discharging can be controlled, or the temperatures of the conductive particles and the waste battery can be controlled within a safe range.
[0012]
Further, in the method for treating a waste battery according to the present invention, it is preferable that the pressure applied to the conductive powder is 10 to 1000 kPa. It is preferable that a movable lid is provided at the opening of the discharge vessel, and the pressure applied to the conductive powder is adjusted by moving the movable lid.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
If discharge treatment is performed before dismantling a waste battery such as a lithium-ion battery, the waste battery can be rendered harmless and heat generation and ignition can be prevented during dismantling. For discharge treatment, it is necessary to connect the positive and negative poles of the waste battery with a conductive substance.However, if a sudden connection is made with a highly conductive substance, the battery or conductor will heat up or spark And the battery containing the flammable solvent may become dangerous.
[0014]
Therefore, in the present invention, by using a conductive powder such as activated carbon having an appropriate resistance and conductivity, and embedding a waste battery having an electrode portion exposed in the conductive powder, the waste battery and the powder are removed. The waste battery can be safely discharged without heating the particles or sparks. Therefore, the waste battery can be discharged to a voltage at which the waste battery can be safely dismantled, and the discharged waste battery can be safely subjected to normal dismantling processing thereafter.
[0015]
The conductive particles used may be carbonaceous particles such as activated carbon or metal particles such as iron. Metal powders can easily be discharged by inserting waste batteries into the powders without pressurizing the powders, but the electrical characteristics change depending on the surface condition of the powders, so the discharge is stable Or there is a risk that heat will be generated by rapid discharge. On the other hand, since the carbonaceous powder has a large contact resistance with the electrode portion, it is difficult for the discharge reaction to occur as it is, but the contact resistance is reduced by pressing the powder and the electrode to press the electrode portion, and the waste battery is discharged. It has the advantage of being able to discharge safely.
[0016]
Further, in the present invention, by adjusting the pressure applied to the conductive powder, the resistance between the electrode portion of the waste battery and the powder particles and between the powder particles changes, for example, when the pressure is increased, the resistance increases. When the pressure decreases, the resistance increases and the discharge becomes difficult. By utilizing the relationship between the pressure applied to the granular material and the discharge, it is possible to control the discharge time of the waste battery until the end of the discharge.
[0017]
Further, when the waste battery discharges through the conductive particles, resistance heat is generated due to resistance between the particles and inside the particles. Generally, when a waste battery is discharged, heat is generated inside the battery. However, in the present invention, since the discharge rate can be adjusted by adjusting the pressure applied to the conductive powder, the waste battery can be estimated from the temperature of the conductive powder at the time of discharge and the temperature of the conductive powder. The temperature of the main body can also be controlled within a safe range.
[0018]
As the conductive powder, in general, a powder having an electric resistance of 10 kΩ · cm or less when no pressure is applied and 10 kΩ · cm or less when a pressure is applied is preferable, and particularly an electric resistance of 10 kPa or more. Those having an electrical resistance of 1 kΩ · cm or less under pressure are more preferable. Preferred conductive particles having such properties include carbonaceous particles containing at least one selected from graphite (graphite), activated carbon, coal, and coke as a main component.
[0019]
The range of the pressure applied to the conductive powder varies depending on the conductivity. Generally, if the pressure is too low, sufficient conductivity cannot be obtained, and the discharge efficiency from the waste battery deteriorates. Becomes longer. However, if the pressure applied to the conductive powder is too high, not only a pressurizing device for obtaining a high pressure is required, but also a container for filling the conductive powder needs a high pressure-capable one. Not preferred.
[0020]
In particular, in the case of a carbonaceous conductive powder, if the pressure applied is less than 10 kPa, the slope of the discharge curve is gentle and a long time is required for the discharge. If it is 60 kPa or more, the discharge is completed in a sufficiently short time and with a small temperature rise. be able to. Conversely, even if a pressure exceeding 500 kPa is applied, the discharge time hardly changes, and applying an excessive pressure exceeding 1000 kPa not only causes an excessive force to the waste battery but also causes troubles such as liquid leakage, Waste due to the increase in the size of the pressurizing device also occurs. Therefore, in the case of carbonaceous conductive powder, the applied pressure is preferably in the range of 10 to 1000 kPa, more preferably in the range of 60 to 500 kPa.
[0021]
The apparatus for discharging a waste battery according to the present invention may be, for example, one in which a grounded discharge vessel 2 is filled with a conductive powder 3 as shown in FIG. The waste battery 1 is buried in the conductive powder 3 and discharged from the exposed electrode portions 1a and 1b as it is or in a state where the conductive powder 3 is pressurized by the movable lid 4 provided in the container opening. Can be done. Therefore, even if the shape and the direction of the waste battery 1 are not arranged in the discharge vessel 2, the discharge can be performed only by reliably bringing the conductive powder 3 into contact with the electrode portions 1 a and 1 b of the waste battery 1. It is also possible to embed a large number of waste batteries 1 in the discharge vessel 2 and discharge them simultaneously.
[0022]
【Example】
(Example 1)
In a discharge vessel (50 × 20 × 20 mm) made of vinyl chloride, (1) commercially available coconut shell activated carbon particles for water purification (particle size: 0.2 to 2 mm), (2) commercially available powder Graphite (particle size: 10 to 50 μm) and (3) iron metal particles (diameter: 3 mm) were filled, and SUS electrode plates were arranged on both inner side surfaces in the longitudinal direction of the container. Each conductive powder was pressed by a movable lid placed at the upper opening of the container, and the electric resistance between the two electrode plates was measured. The results obtained are shown in FIG.
[0023]
The activated carbon granules and the powdered graphite had an electric resistance of 240 kΩ · cm and 26 kΩ · cm, respectively, when not pressurized. However, the electric resistance gradually decreased with an increase in pressure due to the lowering of the movable lid, and the pressure was reduced. The electric resistance at 10 kPa was 1 kΩ · cm or less. On the other hand, in the case of metal particles, the electrical resistance was as high as 640 kΩ · cm even when pressurized at a pressure of 20 kPa. However, when the pressing force was further increased, short-circuit occurred and the electrical resistance decreased rapidly. This change in the electrical resistance of the metal particles is considered to be due to the oxide film on the surface.
[0024]
(Example 2)
One used lithium ion battery (open voltage: 3.0 V) was buried in the container filled with the activated carbon particles of Example 1, and pressure was applied by a movable lid arranged at an upper opening. At that time, the pressure applied to the activated carbon was changed in the range of 30 to 620 kPa, and the open voltage of the waste battery under each pressure was measured for each elapsed time, and the obtained results are shown in FIG.
[0025]
From FIG. 3, it can be seen that the discharge is rapidly discharged from the waste battery as the pressure applied to the activated carbon particles is increased. In particular, at a pressure of 60 kPa or more, the open-circuit voltage drops to 1 V or less in a short time. For example, when a pressure of 310 kPa was applied to the activated carbon particles, the open-circuit voltage of the waste battery dropped from 3.0 V to 0.7 V in 30 minutes, confirming that the discharge was sufficiently performed.
[0026]
At the same time, when the maximum temperature around the waste battery was measured, the pressure applied to the activated carbon particles was only 1 ° C. increase from 22 ° C. to 23 ° C. at 30 kPa, 2 ° C. increase at 160 kPa, and 3 ° C. increase at 300 kPa. Met. In each case, the heat generation was negligibly small and no sparks were observed.
[0027]
In the above embodiment, the discharge experiment was performed with one waste battery. However, if the discharge vessel is enlarged and a plurality of waste batteries are embedded in the conductive powder, the plurality of waste batteries can be efficiently discharged simultaneously. be able to.
[0028]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, before dismantling a used waste battery represented by a lithium ion secondary battery, it does not require a large amount of energy and equipment costs, generates no extra waste or gas, and generates a spark. The waste battery can be discharged and rendered harmless with high efficiency and without an excessive rise in temperature, so that the waste battery can be disassembled safely and at low cost.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing a specific example of a discharge process of a waste battery according to the present invention.
FIG. 2 is a graph showing a relationship between a pressing force and electric resistance in various conductive powders.
FIG. 3 is a graph showing a relationship between an open voltage of a waste battery and an elapsed time at each pressing force applied to activated carbon particles.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 waste battery 2 discharge vessel 3 conductive powder 4 movable lid

Claims (9)

Before dismantling the waste battery, the waste battery with the exposed electrode portion is embedded in the conductive powder filled in the discharge vessel, and the discharge is performed as it is or while applying pressure to the conductive powder. Waste battery treatment method. 2. The waste battery according to claim 1, wherein the electrical resistance of the conductive particles is 10 kΩ · cm or more when no pressure is applied, and 10 kΩ · cm or less when pressure is applied. 3. Processing method. The method for treating a waste battery according to claim 2, wherein the electric resistance of the conductive powder is 1 kΩ · cm or less when a pressure of 10 kPa or more is applied. The waste according to any one of claims 1 to 3, wherein the conductive powder is a powder mainly containing at least one selected from graphite, activated carbon, coal, and coke. Battery treatment method. The method for treating a waste battery according to any one of claims 1 to 4, wherein a time required for discharging is controlled by adjusting a pressure applied to the conductive powder. The temperature of the conductive powder and the waste battery is controlled within a safe range by adjusting a pressure applied to the conductive powder, wherein the temperature is controlled in a safe range. Waste battery treatment method. The method for treating a waste battery according to any one of claims 1 to 6, wherein a pressure applied to the conductive powder is 10 to 1000 kPa. A movable lid is provided at an opening of the discharge vessel, and the pressure applied to the conductive powder is adjusted by moving the movable lid. The method according to claim 1, wherein: Waste battery treatment method. The method for treating a waste battery according to any one of claims 1 to 8, wherein the waste battery is a lithium ion secondary battery.

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