JP5857811B2 - Secondary battery recycling equipment - Google Patents

Description

  The present invention relates to a technology of a secondary battery recycling apparatus.

  When a secondary battery such as a lithium ion secondary battery or a nickel hydride secondary battery is used as a vehicle part such as a hybrid vehicle, for example, when the vehicle is scrapped, the secondary battery is removed from the vehicle. After removal, it is dismantled and useful metals are recovered.

  Generally, a secondary battery used as an automobile part generates a high voltage (for example, 300 V or more), and maintains a high voltage even when the vehicle is removed as a scrap car. There are many. Usually, the work of disassembling the secondary battery is performed manually by an operator wearing protective equipment such as an insulating glove. Therefore, sufficient consideration must be given to ensuring the safety of the work.

  In order to enhance the safety of the secondary battery disassembly work, etc., it is conceivable to discharge the secondary battery. In this case, the secondary battery is stored for a long period of time and discharged naturally, or a resistor, etc. Therefore, it is necessary to forcibly discharge the battery, and the recycling process of the secondary battery takes a long time or takes time, so that the recycling process cannot be performed efficiently.

  Conventionally, various methods for recovering valuable materials from secondary batteries have been proposed (for example, see Patent Documents 1 to 3), and work efficiency of the recycling process has been improved. There is room.

JP 2010-3512 A JP-A-2005-26088 JP 2010-165568 A

  Accordingly, an object of the present invention is to provide a secondary battery recycling apparatus that can ensure the safety of the recycling process and increase the efficiency of the recycling process.

The secondary battery recycling apparatus of the present invention includes a heat treatment tank that heats the secondary battery, a partition that is installed in the heat treatment tank and that forms a circulation path through which the gas in the heat treatment tank circulates, A circulator that is provided in the heat treatment tank and circulates the gas in the heat treatment tank to the circulation path; and a charger that charges the secondary battery when the secondary battery is heated. .

  Moreover, it is preferable that the secondary battery recycling apparatus includes a coolant supply means for supplying a coolant to the secondary battery.

  According to the present invention, it is possible to secure the work safety of the recycling process and increase the efficiency of the recycling process.

It is a schematic diagram which shows an example of the recycling processing apparatus of the secondary battery which concerns on this embodiment. It is a schematic diagram which shows another example of the recycling processing apparatus of the secondary battery which concerns on this embodiment. It is a figure which shows an example of transition of process elapsed time and a secondary battery temperature. It is a schematic diagram which shows another example of the recycling processing apparatus of the secondary battery which concerns on this embodiment. It is a figure which shows an example of transition of the secondary battery temperature by process elapsed time and a charge condition. It is a flowchart for demonstrating the disassembly of a battery pack, and the collection process of valuables.

  An example of a secondary battery recycling apparatus will be described below with reference to the drawings. Here, the term “secondary battery” is not limited to a battery cell as a single battery such as a nickel hydride secondary battery or a lithium ion secondary battery, but a plurality of battery cells (for example, about six or eight batteries). ) A battery module connected in series as one component unit, or a battery pack configured by connecting a plurality of battery modules in series, or a control device for monitoring and controlling the battery pack and the charging state of the battery module, Electronic components such as relays for disconnecting electrical circuits, safety plugs for mechanically disconnecting circuits and cooling blowers for cooling assembled batteries, signal lines and power lines connecting each component, and airtight storage The battery pack etc. comprised from the case etc. which carry out are also included.

  1 includes a heat treatment tank 12, a circulator 14, a replacement gas supply device 16, and a condenser 18.

  The heat treatment tank 12 is mainly for heat treatment of the secondary battery 10, and an electric heater (not shown) and a mounting table on which the secondary battery 10 is placed in the heat treatment tank of the present embodiment. 30. The heat source for heating the secondary battery 10 is not limited to an electric heater, and may be an indirect heating type gas heater such as a radiant tube.

  In the heat treatment tank 12 of this embodiment, a partition wall 22 that forms a circulation path 20 through which the gas in the heat treatment tank 12 circulates is installed. The partition wall 22 of the present embodiment has a box shape surrounding the secondary battery 10 mounted on the mounting table 30, and the space between the outer wall of the partition wall 22 and the inner wall of the heat treatment tank 12 is connected to the circulation path 20. It has become. In the present embodiment, the partition wall 22 above the secondary battery 10 is provided with an inlet 22 a of the circulation path 20, and the lower side of the secondary battery 10 is opened to become the outlet 22 b of the circulation path 20. The shape of the partition wall 22 and the positions of the inlet and the outlet of the present embodiment are merely examples. If the gas in the heat treatment tank 12 is circulated by the circulation path 20 formed by the partition wall 22, it is not always necessary. This is not a limitation.

  The circulator 14 of this embodiment is installed in the vicinity of the inlet 22 a formed in the partition wall 22 so that the gas in the heat treatment tank 12 is circulated through the circulation path 20. Examples of the circulator 14 include a fan and a pump that can adjust a wind direction, a wind speed, and the like.

  Next, the operation of the recycling processing apparatus 1 according to this embodiment will be described.

  First, the open / close door (not shown) of the heat treatment tank 12 is opened, the secondary battery 10 is set on the mounting table 30 in the tank, the open / close door is closed and sealed, and an electric heater (not shown) is switched on, The secondary battery 10 is heated. The temperature control in the heat treatment tank 12 is performed by installing a temperature sensor 24 or the like in the tank, detecting the temperature in the tank, and adjusting the output of the electric heater based on the detected temperature.

  In the present embodiment, the circulator 14 is operated during the heat treatment of the secondary battery 10, the gas in the heat treatment tank 12 is taken in from the inlet 22 a of the circulation path 20, passed through the circulation path 20 and discharged from the outlet 22 b, Further, the gas in the heat treatment tank 12 is circulated through the circulation path 20 so as to be taken in from the inlet 22 a of the circulation path 20. As in the present embodiment, the heat treatment of the secondary battery 10 while forcibly circulating the gas in the heat treatment tank 12 is more than the case where the heat treatment of the secondary battery 10 is performed under natural convection of gas. The heat exchange between the secondary battery 10 and the gas in the heat treatment tank 12 is promoted, the heat treatment time can be shortened, and thus the time required for the recycle process can be shortened, and the work efficiency of the recycle process is improved. be able to.

  When estimating the temperature of the secondary battery 10 by the temperature sensor 24 installed in the tank, the correlation between the temperature measured by the temperature sensor 24 and the actual temperature of the secondary battery 10 is grasped in advance, and the correlation And the temperature measured by the temperature sensor 24 during the heat treatment, the temperature of the secondary battery 10 during the heat treatment is estimated. As in this embodiment, forcibly circulating the gas in the heat treatment tank 12 suppresses the difference between the temperature of the temperature sensor 24 and the temperature of the secondary battery 10 itself, compared to the case of natural convection. The accuracy of temperature estimation of the secondary battery 10 can be improved. And if the precision of the temperature estimation of the secondary battery 10 improves, it will also be possible to set an appropriate heat treatment time.

  When the secondary battery 10 is heated in the heat treatment tank 12 and the temperature of the secondary battery 10 reaches or exceeds the boiling point of the electrolyte in the battery cell, the pressure inside the battery cell rises and is provided in the battery cell. Electrolyte is discharged from the safety valve and the voltage starts to fluctuate. If the heating is further continued, the voltage becomes zero and the battery function is destroyed. For example, in a lithium ion secondary battery using an organic electrolyte and a nickel metal hydride secondary battery using an aqueous electrolyte, the battery function of the secondary battery 10 is destroyed and the voltage is reduced to zero by heating at 150 ° C. or higher. It becomes possible to. Since the secondary battery 10 after such a heat treatment can be safely handled as zero-voltage scrap, it is possible to safely and easily perform disassembly of the secondary battery 10 as a post-process. Therefore, by performing the heat treatment of the secondary battery 10 while forcibly circulating the gas in the heat treatment tank 12 as in the present embodiment, the battery function can be achieved in a shorter time than the heat treatment under conventional natural convection. The secondary battery 10 can be destroyed, that is, the heat treatment time can be shortened to increase the work efficiency of the recycling process, and the secondary battery 10 can be handled safely as zero-voltage scrap. It is also possible to safely and easily carry out 10 dismantling and the like.

  In the heat treatment of the present embodiment, as shown in FIG. 1, a replacement gas supply device 16 that supplies a replacement gas such as water vapor or an inert gas into the heat treatment tank 12 is installed. The space in the heat treatment tank 12 is preferably replaced with a replacement gas such as water vapor or an inert gas to make it oxygen-free. Examples of the replacement gas supply device 16 include a steam boiler such as a once-through boiler that generates water vapor, a gas cylinder filled with an inert gas, and the like. For example, among electrolytes used for lithium ion secondary batteries, an organic electrolyte such as dimethyl carbonate is a flammable material, but the inside of the heat treatment tank 12 is replaced with a replacement gas to make an oxygen-free state. Even if the organic electrolyte is released from the secondary battery 10 by the heat treatment, combustion in the heat treatment tank 12 is suppressed.

  In this embodiment, it is preferable to install the condenser 18 like the recycling processing apparatus shown in FIG. During the heat treatment of the secondary battery 10, the electrolytic solution used in the secondary battery 10 becomes a thermal decomposition product (gas) and stays in the heat treatment tank 12. When such a gas such as a thermal decomposition product is extracted from the heat treatment tank 12 and supplied to the condenser 18, the thermal decomposition product is cooled and liquefied, so that it can be recovered as a waste liquid. The condenser 18 is mainly for condensing the thermal decomposition products and the like released from the secondary battery 10. For example, an indirect water-cooled heat exchanger such as a shell and tube type, a plate fin type, or the like is used. A surface heat exchanger and the like can be mentioned.

  FIG. 2 is a schematic diagram illustrating another example of the secondary battery recycling apparatus according to the present embodiment. In the recycle processing device 2 shown in FIG. 2, the same components as those in the recycle processing device 1 shown in FIG. Note that the replacement gas supply device 16 and the condenser 18 shown in FIG. A spray nozzle 26 as an example of a coolant supply means is installed in the heat treatment tank 12 shown in FIG. 2, and after the heat treatment, a coolant (for example, water) is supplied from the spray nozzle 26 to the secondary battery 10. Is supplied, and the secondary battery 10 is cooled. In addition, it is preferable to provide the cooling liquid tank (not shown) connected to the nozzle 26 for spraying via piping etc. out of the heat processing tank 12. FIG. Further, the spray nozzle 26 is an example, and is not limited to this as long as the coolant can be supplied to the secondary battery 10.

  FIG. 3 is a diagram illustrating an example of the transition of the processing elapsed time and the secondary battery temperature. As shown in FIG. 3, the temperature of the secondary battery rises with the lapse of time of the heat treatment, and the secondary battery becomes high temperature. After the heat treatment, it is necessary to cool the secondary battery in order to take out the secondary battery from the heat treatment tank and perform the subsequent treatment. However, as shown in FIG. The time required for recycling increases, and the work efficiency of the recycling process decreases. However, after the heat treatment as in the present embodiment, by supplying the coolant from the spray nozzle to the secondary battery, the time for cooling the secondary battery can be shortened from the natural cooling as shown in FIG. Therefore (Δt), it becomes easy to shift to the subsequent process, and the work efficiency of the recycling process can be improved.

  FIG. 4 is a schematic diagram illustrating another example of the secondary battery recycling apparatus according to the present embodiment. In the recycling processing apparatus 3 shown in FIG. 4, the same reference numerals are given to the same configurations of the recycling processing apparatus 2 shown in FIG. 2, and description thereof is omitted. In addition, in the recycling processing apparatus 3 of FIG. 4, the replacement gas supply apparatus 16 and the condenser 18 which were shown in FIG. 1 are abbreviate | omitted. The recycle processing apparatus 3 shown in FIG. 4 includes a charger 28 that charges the secondary battery 10 during the heat treatment. Here, the charging of the secondary battery 10 at the time of heat treatment includes not only the case of charging the secondary battery 10 during the heat treatment but also the case of charging the secondary battery 10 before the heat treatment. For example, after the secondary battery 10 is set on the mounting table 30 in the heat treatment tank 12 (or before the secondary battery 10 is put into the heat treatment tank 12), the secondary battery 10 is connected to the charger 28. The charging of the secondary battery 10 by the charger 28 is started before or after the electric heater is turned on.

  FIG. 5 is a diagram illustrating an example of transition of the secondary battery temperature depending on the processing elapsed time and the state of charge. FIG. 5A shows a case where the heat treatment is performed in a state where the secondary battery is charged, FIG. 5B shows a case where the heat treatment is performed in a state where the secondary battery is in an intermediate state, and FIG. It is a temperature transition of a secondary battery at the time of performing heat processing in the state with a low charge state of a secondary battery. In addition, it switches from heating to a heating stop on the boundary of the vertex of the curve of A, B, C of FIG. As shown in FIG. 5, the higher the state of charge of the secondary battery, the faster the temperature of the secondary battery rises due to the heat treatment, and the temperature reaches the specified temperature that destroys the battery function of the secondary battery. Thus, it is possible to shorten the heat treatment time including the above, and to reduce the time required for the recycle process, and to improve the work efficiency of the recycle process.

  The secondary battery in which the battery function is destroyed and the electrolytic solution is released by the heat treatment as described above is transported to the secondary battery disassembly and valuable material recovery process. In particular, even in the case of a battery pack composed of electronic parts, signal lines, power lines, cases, etc. together with battery cells, the battery function is destroyed and the electrolyte solution is released. The entire process from dismantling to collection of valuable materials can be automated without requiring dangerous manual work (battery pack dismantling work) by the operator. As a result, a safe and inexpensive secondary battery can be recycled.

  FIG. 6 is a flowchart for explaining the dismantling of the battery pack and the recovery process of the valuables. Here, a battery pack of a lithium ion secondary battery will be described as an example, but the same can be applied to a battery pack of a nickel hydride secondary battery. In addition, the recovery process of valuable materials described below mainly includes an electrode foil (Al, Cu) used as a current collector of a lithium ion secondary battery, and a transition metal (Ni, Mn, used as a positive electrode material). Co, etc.), and recovers lithium present in the positive electrode material and the negative electrode material. Moreover, the flow shown in FIG. 6 is an example of a process for collecting battery packs and valuables, and is not limited thereto.

  As shown in FIG. 6, in step S <b> 10, the battery pack that has been subjected to the heat treatment described above is crushed. When the battery pack is heat-treated, the thermoplastic resin, which is the constituent material of the battery pack, is thermally decomposed to a state that is greatly different from the original, but the electrolyte in the battery cell is discharged to the outside and the battery function Is a safe and destroyed state. Therefore, in the crushing process, it is more time-consuming and safer to crush the battery pack directly into a shredder machine (such as a large hammer mill) than to dismantle it manually. This is preferable. Moreover, before crushing a battery pack with a shredder machine etc., you may perform the process of immersing a battery pack in water and discharging a battery cell. In addition, this shredder machine etc. can use what is generally used in a process of a scrap car and a waste home appliance.

  By crushing the battery pack using a shredder machine, non-priced materials such as resin are discharged as shredder dust. On the other hand, among the battery cells in the battery pack, an aluminum case or the like that is an exterior of the battery cell becomes a metal piece with a large specific gravity, and an electrode foil (including a positive electrode material and a negative electrode material) becomes a metal scrap with a small specific gravity. . Shredder dust is disposed of in a landfill according to the disposal law. Moreover, as a condition for landfill, it is necessary to satisfy the management-type landfill standard.

  Next, in step S12, the above-described metal piece having a large specific gravity and metal scrap having a low specific gravity are subjected to wind sorting to collect the metal piece having a large specific gravity. Instead of wind sorting, metal pieces having a large specific gravity may be recovered by magnetic sorting.

Next, in step S14, metal waste having a small specific gravity such as an electrode foil (including a positive electrode material and a negative electrode material) is washed with water to convert lithium in the negative electrode material and lithium in the positive electrode material into lithium hydroxide. The transition metal in the material is changed to a hydroxide. The reaction when lithium nickelate is used as the positive electrode material is shown below.
3LiNiO ₂ + 4.5H ₂ O → 3LiOH + 3Ni (OH) ₂ + 4 / 3O ₂

Lithium hydroxide easily dissolves in water to form an aqueous solution, and transition metal hydroxides such as nickel hydroxide have very low solubility in water, and thus hardly dissolve and become solids. The solubility of nickel hydroxide is 0.0013 g / 100 cm ³ .

  Next, in step S16, the aqueous solution such as lithium hydroxide and the solid content such as nickel hydroxide are sieved by the vibration sieve device or the like. In step S18, carbon dioxide gas is introduced into the aqueous lithium hydroxide solution to neutralize it to obtain lithium carbonate, which is recovered by precipitation filtration.

  In step S20, solid content such as transition metal hydroxide such as nickel hydroxide is put into the leaching tank, and acid such as hydrochloric acid is added to change the transition metal hydroxide into water-soluble metal chloride. Let A metal chloride solution such as nickel chloride is extracted, and the process proceeds to step S30 described later, and is recycled to a product such as metal or nickel sulfate as a nickel raw material by an existing smelting process.

  When hydrochloric acid is added (step S20), in the leaching tank, unreacted metal hydroxide such as nickel hydroxide (positive electrode material), separator, and aluminum (electrode foil) are levitated, and the negative electrode material (carbon) and Since copper (electrode foil) settles, these can be separated. In the following description, the levitated material that has floated in the leaching tank is referred to as a floating electrode material, and the sediment that has settled in the leaching tank is referred to as a sediment electrode material. In step S20, when sulfuric acid is added instead of hydrochloric acid, unreacted metal hydroxide such as nickel hydroxide, separator, aluminum (electrode foil), negative electrode material (carbon) and copper (electrode foil) are all precipitated. Resulting in. The reason why it is possible to separate the floating electrode material and the sedimented electrode material by adding hydrochloric acid is that it occurs in the process of corroding aluminum when hydrochloric acid is added in addition to the difference in specific gravity between copper and aluminum. This is considered to be because the apparent specific gravity of aluminum is lower than 1 because the generation rate of hydrogen gas is higher than when sulfuric acid is added. Therefore, in the subsequent copper recovery, it is preferable to add hydrochloric acid in terms of increasing the purity of copper and increasing the added value as a recycled material. Even when sulfuric acid is added, valuable metals such as Ni can be recovered in the subsequent steps.

  Next, in step S22, the floating electrode material separated from the leaching tank is put into the cleaning tank, and hydrochloric acid is added and stirred and washed. Thereby, the transition metal hydroxide such as nickel hydroxide attached to the aluminum or the separator is changed to a water-soluble metal chloride. And in step S24, it sifts into solid content, such as aluminum and a separator, and metal chloride solutions, such as nickel chloride, with a vibration sieve apparatus. The sieved aluminum or separator may be collected as a recycled material or discarded. On the other hand, the metal chloride solution such as nickel chloride proceeds to step S30 and is refined by an existing smelting process, and is recycled to a product such as metal or nickel sulfate as a nickel raw material, for example.

  In step S26, the sedimentation electrode material separated from the leaching tank is put into the washing tank in the same manner as described above, and hydrochloric acid is added and washed with stirring. Thereby, the hydroxide of transition metals, such as nickel hydroxide, adhering to copper is changed into a water-soluble metal chloride. And in step S28, it sifts into solid content, such as copper, and metal chloride solutions, such as nickel chloride, with a vibration sieve apparatus. The sieved copper is recovered as recycled material. On the other hand, the metal chloride solution such as nickel chloride proceeds to step S30 in the same manner as described above, and is refined by an existing smelting process, for example, recycled as a nickel raw material to a product such as metal or nickel sulfate.

  1-3 Recycling device, 10 Secondary battery, 12 Heat treatment tank, 14 Circulator, 16 Replacement gas supply device, 18 Condenser, 20 Circulation path, 22 Bulkhead, 22a Inlet, 22b Outlet, 24 Temperature sensor, 26 Spray Nozzle, 28 charger, 30 mounting table.

Claims (2)

A heat treatment tank for heating the secondary battery;
A partition that is installed in the heat treatment tank and forms a circulation path through which the gas in the heat treatment tank circulates;
A circulator provided in the heat treatment tank and circulating the gas in the heat treatment tank to the circulation path;
A rechargeable battery recycling apparatus comprising: a charger that charges the secondary battery when the secondary battery is heated .   2. The secondary battery recycling apparatus according to claim 1, further comprising a coolant supply means provided in the heat treatment tank and configured to supply a coolant to the secondary battery.

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