Patent Description:
According to the statistics of the Ministry of Industry and Information Technology, the production and sales of new energy vehicles in China were <NUM>,<NUM>,<NUM> and <NUM>,<NUM>,<NUM> respectively in <NUM>. In <NUM>, the output of lithium-ion batteries was <NUM> billion with an increase of <NUM>% over the previous year. The service life of 3C small battery is generally <NUM>-<NUM> years, and the service life of the power battery is generally <NUM>-<NUM> years. A large number of battery applications are likely to lead to scrapping of a large number of batteries. If the waste batteries are not effectively treated, it will cause serious harm to the environment. The waste batteries contain organic substances such as separators, binders and electrolytes, which need to be subjected to harmless treatment at a high temperature during treatment.

The traditional high-temperature treatment method is a method using aerobic pyrolysis or anaerobic cracking singly. The traditional aerobic pyrolysis method is easy to produce dioxin in the pyrolysis process, and there is a risk of secondary pollution; and furthermore, a lot of heat is produced by pyrolysis and cannot be recovered, which enables control on a temperature in a furnace to be difficult. The traditional anaerobic cracking method produces tar, cokes and other products after cracking, racked products have a negative impact on the subsequent battery recycling process, resulting the problems of increasing acid and alkali consumption, solid waste residues and the difficulty of wastewater treatment and the like, so that the limitation is obvious.

Zhou LiFeng et al. compare some advantages and disadvantages among hydrometallurgical process, pyrometallurgical process and direct physical recycling process (<NPL>), It is indicated that pyrometallurgy could cause the low recovery efficiency, high energy consumption and the production of toxic gases (dioxins, furans, etc.). Therefore, there is a need to develop high recovery rate, low energy consumption and low environmental hazard recycling method and apparatus <CIT> discloses a further known prior art.

The objective of the present disclosure is to provide a cracking method and a cracking apparatus for a power battery. In the method, by combining battery cracking and battery pyrolysis, secondary pollution and the impact of cracked products on subsequent processes can be avoided, and the heat after cracking can be recovered.

In order to achieve the above objective, the present disclosure adopts the following technical solution.

A vacuum cracking method for a power battery, includes the following steps that:.

Preferably, the step (<NUM>) further includes discharge treatment on the waste power batteries before the rolling.

Preferably, in the step (<NUM>), the rolling is performed with a pressure of <NUM>-<NUM> MPa, a rotating speed of <NUM>-<NUM>/s, and a rolling gap width of <NUM>-<NUM>.

Preferably, in the step (<NUM>), the cracking is gradient cracking with gradient temperatures of <NUM>-<NUM>, <NUM>-<NUM> and <NUM>-<NUM> and a cracking time of <NUM>-<NUM>.

Preferably, in the step (<NUM>), the heating is performed at a heating rate of <NUM>-<NUM>/min.

Preferably, in the step (<NUM>), the cracked gas is a mixture of C3-C12 alkenes and alkanes.

Preferably, in the step (<NUM>), the preheating is performed at a temperature of <NUM>-<NUM>.

Preferably, in the step (<NUM>), the inert atmosphere is a nitrogen atmosphere; and the vacuum pressure is <NUM>-<NUM> kPa.

Preferably, in the step (<NUM>), the cracked gas is used as a fuel for pyrolysis in the step (<NUM>).

Preferably, in the step (<NUM>), a pyrolysis temperature is <NUM>-<NUM>, a pyrolysis time is <NUM>-<NUM>, a pyrolysis pressure is atmospheric pressure, the atmosphere is air, and a rotating speed of a pyrolysis paddle is <NUM>-<NUM> r/min.

Preferably, in the step (<NUM>), the cathode material powder is one of nickel cobalt lithium manganese, lithium iron phosphate or lithium manganese; and the anode material powder is one of graphite or lithium titanate.

Preferably, in the step (<NUM>), valuable metal elements such as metal Li, Ni, CO and Mn are further be extracted from the cathode material powder or anode material powder by a hydrometallurgical method commonly used in the art.

A vacuum cracking apparatus for the power battery includes a cylinder and further includes following components arranged sequentially from top to bottom:.

According to some embodiments of the present disclosure, the cracking unit further includes a first screw arranged transversely, a second driving unit, a barrel body, a propeller, a third driving unit and a first bottom plate. The second driving unit is used for driving the first screw to rotate, the third driving unit is used for driving the propeller to rotate, the barrel body is installed below the first screw, the first bottom plate is installed below the barrel body, and the propeller is located in the barrel body and installed on the first bottom plate; the diameter of the barrel body is smaller than that of the cylinder, an opening of the barrel body faces downward, and a clearance space is formed between the opening of the barrel body and the first bottom plate; and a spindle of the propeller is hollow, where the cracked material falls onto the second sealing unit through the hollow portion of the spindle.

Further, according to some examples of the present disclosure, air guide holes are formed in the spindle and the barrel body respectively.

Further, according to some examples of the present disclosure, the first mixing paddle includes a first shaft and a plurality of blade groups, the plurality of blade groups are distributed on the first shaft at intervals, each blade group includes a plurality of first blades, and a plurality of first blade are circumferentially arranged on the outer surface of the first shaft at intervals.

Further, according to some examples of the present disclosure, each of the first sealing unit, the second sealing unit and the third sealing unit includes a circular column, a plug and a fourth driving unit, where the outer surface of the circular column is abutted against the inner surface of the cylinder, a guide groove is formed in the middle part of the circular column, the plug moves up and down along the guide groove, the fourth driving unit is used for driving movement of the plug, and a plurality of pouring grooves are formed in the circular column and are connected with the guide groove and the bottom of the circular column respectively.

Further, according to some examples of the present disclosure, each pressure roller is provided with a plurality of first hobbing teeth and a plurality of second hobbing teeth with the diameters smaller than those of the first hobbing teeth; and for every two pressure rollers, the first hobbing teeth of the upper pressure roller correspond to the second hobbing teeth of the lower pressure roller, and the second hobbing teeth of the upper pressure roller correspond to the first hobbing teeth of the lower pressure roller.

Further, according to some examples of the present disclosure, a feeding unit is arranged above a rolling unit, is installed on the cylinder and includes a feed hopper, a discharge port and a sixth driving unit. A feed slot is formed in the feed hopper, the bottom of the feed slot is connected with the discharge port, the discharge port is connected with the cylinder, a second screw is arranged in the feed slot, and the sixth driving unit is used for driving the second screw to rotate.

Further, according to some examples of the present disclosure, the fourth driving unit includes a screw rod, a worm wheel, a worm and a first motor. A through hole is formed in the middle part of the plug and is provided with threads, the plug is connected with the screw rod, the screw rod is connected with the worm wheel, the worm wheel is connected with the worm, and the worm is connected with the first motor.

Further, according to some examples of the present disclosure, the upper end surface of each circular column is in a conical shape.

Further, according to some examples of the present disclosure, a main view shape of the plurality of blade groups installed on the first shaft is matched with a shape of the upper end surface of the circular column of the third sealing unit.

Additional aspects and advantages of the present disclosure will become apparent and easy to understand from the description of embodiments in combination with the following drawings, where:.

Reference numerals: cylinder <NUM>, first sealing unit <NUM>, circular column <NUM>, guide groove <NUM>, pouring groove <NUM>, plug <NUM>, through hole <NUM>, fourth driving unit <NUM>, screw rod <NUM>, worm wheel <NUM>, worm <NUM>, first motor <NUM>, cracking unit <NUM>, first heater <NUM>, heat insulation layer <NUM>, first air inlet <NUM>, first air outlet <NUM>, pipeline <NUM>, first screw <NUM>, second driving unit <NUM> barrel body <NUM>, clearance space <NUM>, air guide hole <NUM>, propeller <NUM>, third driving unit <NUM>, spindle <NUM>, first bottom plate <NUM>, second sealing unit <NUM>, pyrolysis unit <NUM>, second heater <NUM>, second air inlet <NUM>, second air outlet <NUM>, first mixing paddle <NUM>, first shaft <NUM>, paddle group <NUM>, first paddle <NUM>, first driving unit <NUM>, third sealing unit <NUM>, rolling unit <NUM>, pressure roller <NUM>, first hobbing teeth <NUM>, second hobbing teeth <NUM>, fifth driving unit <NUM>, feeding unit <NUM>, feed hopper <NUM>, feed slot <NUM>, discharge port <NUM>, sixth driving unit <NUM>, second screw <NUM>, discharging unit <NUM>, first stop dog <NUM>, third screw <NUM>, discharge opening <NUM> and second motor <NUM>.

In order to make the technical solution of the present disclosure more clearly understood by those skilled in the art, the following embodiments are listed for description. It should be noted that the following embodiments do not limit the protection scope defined by the present disclosure.

Unless otherwise specified, all the raw materials, reagents or apparatuses used in the following embodiments may be obtained from conventional commercial channels or through existing known methods.

A vacuum cracking method for a power battery, including the following steps that:.

A method of anaerobically cracking a power battery, including the following steps that:.

A method of aerobically cracking a power battery, including the following steps that:.

The air outlets of Embodiments <NUM>-<NUM> and Comparative examples <NUM>-<NUM> are detected to obtain results as shown in Tables <NUM>-<NUM>.

For comparative example <NUM>, only anaerobic cracking is used, while pure anaerobic cracking is relatively high in energy consumption, and long in reaction time. Traditional cracking is static cracking, through which solid reactants do not move, cathode and anode materials and carbon produced by cracking can cover organic substances to be cracked, so that continuous occurrence of cracking reaction is inhibited, and the yield of the cracked gas is relatively low.

The disadvantages of using only aerobic pyrolysis by comparative example <NUM> are as follows: (<NUM>) the dioxin can be produced to cause relatively great environmental pollution, and products that may be reused (cracked gas) cannot be produced;(<NUM>) after ignition, the organic substances can be burnt instantly, and a temperature in a furnace can be raised rapidly, so that control on the temperature in the furnace and control on the reaction process are difficult, and the combustion degree is not liable to control; and (<NUM>) a pyrolysis furnace is usually not sealed, so that a certain quantity of tail gas can escape during reaction, which is not friendly to the environment.

After the waste power batteries are treated by the vacuum cracking method of the present disclosure, the yield of the cracked gas is high, the cracked gas is completely burnt, and no dioxin and almost no VOCs are produced.

Referring to <FIG>, the vacuum cracking apparatus for the power battery according to Embodiment <NUM> of the present disclosure includes a cylinder <NUM> and further includes following components sequentially arranged from top to bottom:.

For example, as shown in <FIG>, the cylinder <NUM> is placed vertically; the first heater <NUM> and the second heater <NUM> are cylindrical gas burners using cracked gas as a fuel, specifically, referring to existing cylindrical gas burners; the first sealing unit <NUM>, the second sealing unit <NUM> and the third sealing unit <NUM> are used for sealing the cracking unit <NUM> and the pyrolysis unit <NUM> and transporting materials; and specifically, the first sealing unit <NUM>, the second sealing unit <NUM> and the third sealing unit <NUM> may be switching valves, or may further be designed in such a way that a moving plate and an air cylinder used for driving movement of the moving plate are arranged in the cylinder <NUM>, and the moving plate moves from left to right to realize functions of sealing and conveying; and the first driving unit <NUM> may be a motor for rotating the air cylinder.

Working process: the waste batteries pass through the feed hopper <NUM> and then enter the rolling unit <NUM>. Firstly, the waste batteries pass through a rolling zone, are fractured or broken under the action of the pressure rollers and then enter a temporary storage zone; the first sealing unit <NUM> is opened, so that the rolled batteries fall into the cracking unit <NUM>, nitrogen is introduced through the first air inlet <NUM>, and the first heater <NUM> is activated, so that the rolled batteries are heated in nitrogen to be cracked; in the process of cracking the batteries, the cracked gas, the solid cracked products and the non-crackable products can be produced; the cracked gas is discharged into the pipeline <NUM> through the first gas outlet <NUM>, and the pipeline <NUM> continuously provides the cracked gas to the first heater <NUM> and preheats the first heater <NUM>, so that the first heater <NUM> is replenished with the fuel, and then the first heater <NUM> is ensured to continuously heat the crushed battery; after cracking, the second sealing unit <NUM> is opened to enable the solid cracked products and the non-crackable products to fall into the pyrolysis unit <NUM>, then the first sealing unit <NUM> and the second sealing unit <NUM> are closed to seal the cracking unit <NUM>, and at the same time, the cracking unit <NUM> cracks the next batch of waste batteries, so that continuous production of the cracked gas is ensured, and then supply of the fuel to the first heater <NUM> and the second heater <NUM> is ensured; oxygen is introduced into the pyrolysis unit <NUM> through the second air inlet <NUM>, and the second heater <NUM> and the first stirring paddle <NUM> are started at the same time, so that the solid cracked products and the non-crackable products are continuously rolled in an oxygen-containing state, so that the cracked products produced generated after cracking of the waste batteries are completely decomposed; and the tail gas after pyrolysis is discharged from the pyrolysis unit <NUM> through an exhaust port, and the pyrolyzed batteries are discharged and cooled through the third sealing unit <NUM> and then enter the next treatment procedure.

For the vacuum cracking apparatus for the power battery according to the embodiments of the present disclosure, the first sealing unit, the second sealing unit and the third sealing unit are installed to isolate the cracking unit <NUM> from the pyrolysis unit <NUM> and be capable of realizing material transmission and gas isolation without interference with each other, so that gas stirring between an anaerobic zone and an aerobic zone is avoided, the yield of the cracked gas is increased, and production of harmful by-products such as dioxin is effectively avoided at the same time; and by combining battery cracking with battery pyrolysis, the advantages of both of battery cracking and battery pyrolysis are fully used, and the disadvantages of battery cracking and battery pyrolysis are overcome, for example, the batteries are cracked to avoid the harm of producing the dioxin by the traditional pyrolysis process; the pyrolysis is conducted after cracking, and the tar and the cokes produced after cracking are completely decomposed through aerobic pyrolysis, so that the problem of increasing acid and alkali consumption, solid waste residues and the difficulty of wastewater treatment and the like caused by by-products of the traditional single cracking process to the subsequent process are solved; and by using the cracked gas discharged after cracking as a fuel for cracking and pyrolysis or preheating the pyrolysis unit, resources are fully used.

In some embodiments of the present disclosure, as shown in <FIG>, the cracking unit <NUM> further includes a first screw <NUM> arranged transversely, a second driving unit <NUM>, a barrel body <NUM>, a propeller <NUM>, a third driving unit <NUM> and a first bottom plate <NUM>. The second driving unit <NUM> is used for driving the first screw <NUM> to rotate, the third driving unit <NUM> is used for driving the propeller <NUM> to rotate, the barrel body <NUM> is installed below the first screw <NUM>, the first bottom plate <NUM> is installed below the barrel body <NUM>, and the propeller <NUM> is located in the barrel body <NUM> and installed on the first bottom plate <NUM>; the diameter of the barrel body <NUM> is smaller than that of the cylinder <NUM>, an opening of the barrel body <NUM> faces downward, and a clearance space <NUM> is formed between the opening of the barrel body <NUM> and the first bottom plate <NUM>; and a spindle <NUM> of the propeller <NUM> is hollow, where the cracked material falls onto the second sealing unit <NUM> through the hollow portion of the spindle <NUM>. For example, during working, the second driving unit <NUM> is started to enable the first screw <NUM> to rotate, the second sealing unit <NUM>, the first heating unit and the third driving unit <NUM> are opened to enable the crushed waste batteries to fall onto the first screw <NUM>, and the first screw <NUM> pushes the waste batteries to move to fall onto the first bottom plate <NUM> from a space between the inner wall of the cylinder <NUM> and the outer surface of the barrel body <NUM>, the waste batteries are heated by the first heater <NUM> in the falling process, the waste battery at the bottom is lifted to the top of the propeller <NUM> by the rotating propeller <NUM>, and since the spindle <NUM> of the propeller <NUM> is hollow, the waste battery on the top falls into the spindle <NUM> and waits for the second sealing unit <NUM> to open; since the waste batteries are heated for the first time in the falling process and are lifted by the propeller <NUM> for secondary heating, gradient cracking and full cracking of the waste batteries are achieved, and thus the cracked gas with a high calorific value is produced; the cracked gas with the high calorific value is led to the second heater <NUM> through the pipeline <NUM> to enable the second heater <NUM> to be preheated by the cracked gas with the high calorific value, so that a preheating time of the pyrolysis unit <NUM> is reduced, and a pyrolysis speed is increased; and the second driving unit <NUM> and the third driving unit <NUM> may be motors and rotating cylinders, a worm wheel is connected with the spindle <NUM>, the worm <NUM> is connected with the worm wheel, and a worm <NUM> is connected with the motor.

In a further example of the present disclosure, as shown in <FIG>, both the spindle <NUM> and the barrel body <NUM> are provided with air guide holes <NUM> respectively to discharge the pyrolysis gas in the spindle <NUM> and the pyrolysis gas in the barrel body <NUM>.

In a further example of the present disclosure, as shown in <FIG> and <FIG>, the first mixing paddle <NUM> includes a first shaft <NUM> and a plurality of blade groups <NUM>, the plurality of blade groups <NUM> are distributed on the first shaft <NUM> at intervals, each blade group <NUM> includes a plurality of first blades <NUM>, and the plurality of first blades <NUM> are circumferentially arranged on the outer surface of the first shaft <NUM> at intervals. For example, the first mixing paddle <NUM> is arranged transversely, the plurality of blade groups <NUM> are sequentially arranged on the first shaft <NUM> from left to right at intervals, each blade group <NUM> includes a plurality of first blades <NUM>, and the plurality of first blades <NUM> take the first shaft <NUM> as the center and are circumferentially arranged on the outer surface of the first shaft <NUM> at intervals. Specifically, the amount of the plurality of blade groups <NUM> may be two, three or more, and the amount of the plurality of first blades <NUM> may be two, three or more. When there are four first blades <NUM>, the four first blades <NUM> are arranged in a cross. The plurality of blade groups <NUM> are arranged to continuously stir pyrolysis products to prevent product accumulation and refine the products, so that a refined product reacts with the second heater <NUM> and oxygen, and then a speed of pyrolyzing the product is increased; and the first blades <NUM> of the blade group <NUM> located in the middle of the first shaft <NUM> are in a shape of "Y", and the first blades <NUM> of the other blade groups <NUM> are in a shape of "T", so that the pyrolysis products at the bottom are conveniently stirred.

In some examples of the present disclosure, as shown in <FIG> and <FIG>, each of the first sealing unit <NUM>, the second sealing unit <NUM> and the third sealing unit <NUM> includes a circular column <NUM>, a plug <NUM> and a fourth driving unit <NUM>, where the outer surface of the circular column <NUM> is abutted against the inner surface of the cylinder <NUM>, a guide groove <NUM> is formed in the middle part of the circular column <NUM>, the plug <NUM> moves up and down along the guide groove <NUM>, the fourth driving unit <NUM> is used for driving the plug <NUM> to move, and a plurality of pouring grooves <NUM> are formed in the circular column <NUM> and are connected with the guide groove <NUM> and the bottom of the circular column <NUM> respectively. For example, the fourth driving unit <NUM> may drive the air cylinder, or may be designed in such as way that the plug <NUM> is connected with the screw <NUM>, the screw <NUM> is connected with a driven wheel, the driven wheel is connected with a driving wheel through a chain, and the driving wheel is connected with the motor. During working, the fourth driving unit <NUM> drives the plug <NUM> to move up and down in the guide groove <NUM>. The plug <NUM> blocks entry of the waste batteries when moving to the position higher than the pouring grooves <NUM>; and when the plug <NUM> moves to the position lower than the pouring grooves <NUM>, the waste batteries flow to the position below the circular column <NUM> through the pouring grooves <NUM>. Specifically, the pouring grooves <NUM> are "O" shaped grooves, and the amount of the plurality of pouring grooves <NUM> may be one, two or more.

In some examples of the present disclosure, as shown in <FIG> and <FIG>, for every two pressure rollers <NUM>, the first hobbing teeth <NUM> of the upper pressure roller <NUM> correspond to the second hobbing teeth <NUM> of the lower pressure roller <NUM>, and the second hobbing teeth <NUM> of the upper pressure roller <NUM> correspond to the first hobbing teeth <NUM> of the lower pressure roller <NUM>. The rolling unit <NUM> can may be two mutually matched hobbing teeth driven by a motor, or three triangularly distributed hobbing teeth driven by the motor. For example, for the two pressure rollers <NUM>, the arrangement manner of the first hobbing teeth <NUM> and second hobbing teeth <NUM> on one pressure roller <NUM> is as follows: the first hobbing teeth <NUM>, the second hobbing teeth <NUM>, the first hobbing teeth <NUM>, the second hobbing teeth <NUM>, the first hobbing teeth <NUM>, etc., while the arrangement manner of the first hobbing teeth <NUM> and second hobbing teeth <NUM> on the other pressure roller <NUM> is as follows: the second hobbing teeth <NUM>, the first hobbing teeth <NUM>, the second hobbing teeth <NUM>, the first hobbing teeth <NUM>, the second hobbing teeth <NUM>, etc., and the two kinds of hobbing teeth are mutually matched to enable the waste batteries to be broken or fractured between the two kinds of hobbing teeth. Specifically, a gap between every two hobbing teeth may be adjusted, the cracking degree and the particle size of the rolled batteries are controlled by adjusting the gap between the two hobbing teeth, and the rolling unit <NUM> is further provided with a pressure relief valve; and the fifth driving unit <NUM> is a motor or a rotating cylinder.

In some examples of the present disclosure, as shown in <FIG> and <FIG>, a feeding unit <NUM> is arranged above the rolling unit <NUM>, is installed on the cylinder <NUM> and includes a feed hopper <NUM>, a discharge port <NUM> and a sixth driving unit <NUM>. A feed slot <NUM> is formed in the feed hopper <NUM>, the bottom of the feed slot <NUM> is connected with the discharge port <NUM>, and the discharge port <NUM> is connected with the cylinder <NUM>, a second screw <NUM> is arranged in the feed slot <NUM>, and the sixth driving unit <NUM> is used for driving the second screw <NUM> to rotate. During working, the sixth driving unit <NUM> is started, the waste batteries are put into the feed hopper <NUM> fall into the feed slot <NUM> and are pushed by the second screw <NUM> to move so as to fall onto the rolling unit <NUM> through the discharge port <NUM>; and the sixth driving unit <NUM> may be a motor or a rotating cylinder.

In a further example of the present disclosure, as shown in <FIG>, the fourth driving unit <NUM> includes a screw <NUM>, a worm wheel <NUM>, a worm <NUM> and a first motor <NUM>. A through hole <NUM> is formed in the middle part of the plug <NUM> and is provided threads, the plug <NUM> is connected with the screw <NUM>, the screw <NUM> is connected with the worm wheel <NUM>, the worm wheel <NUM> is connected with the worm <NUM>, and the worm <NUM> is connected with the first motor <NUM>. During working, the first motor <NUM> is started to drive the worm <NUM> to rotate, the worm <NUM> drives the worm wheel to rotate, the worm wheel drives the screw <NUM> to rotate, and then the screw <NUM> drives the plug <NUM> to move up and down; the worm wheel and worm <NUM> are matched with the screw <NUM> to withstand the impact of falling of the waste batteries by using the self-locking characteristics of the worm wheel <NUM> and worm <NUM>.

In a further example of the present disclosure, as shown in <FIG>, the upper end surface of the circular column <NUM> is in a conical shape to guide the waste batteries to converge at the middle part of the circular column <NUM> for facilitating transmission of the waste batteries.

In a further example of the present disclosure, as shown in <FIG>, a main view shape of the plurality of blade groups <NUM> installed on the first shaft <NUM> is matched with the shape of the upper end surface of the circular column <NUM> of the third sealing unit <NUM>. Specifically, the upper end surface of the circular column <NUM> is in a conical shape, and the first mixing paddle <NUM> is in a "diamond" shape matched with the conical shape; and with such a structure, the cracked products at the bottom of the first mixing paddle <NUM> are fully stirred.

In some examples of the present disclosure, as shown in <FIG>, the outer surface of the first heater <NUM> and the outer surface of the second heater <NUM> are both provided with heat insulation layers <NUM> to prevent hot gas loss and preserve heat.

In some examples of the present disclosure, as shown in <FIG>, a discharging unit <NUM> is arranged below the third sealing unit <NUM> and includes a first stop dog <NUM>, a third screw <NUM>, a discharge opening <NUM> and a second motor <NUM>. The third screw <NUM> is arranged below the first stop dog <NUM>, the discharge opening <NUM> is located below the first stop dog <NUM> and below the third screw <NUM>, and the second motor <NUM> is used for driving the third screw <NUM> to rotate. Specifically, one end of the first stop dog <NUM> is arranged on one side of the inner wall of the cylinder <NUM>, the other end of the first stop dog <NUM> extends to the middle part of the cylinder <NUM>, and a shape of the first stop dog <NUM> is a right triangle. During working, the material after pyrolysis falls onto the first stop dog <NUM>, falls onto the third screw <NUM> through an inclined plane of the first stop dog <NUM> and is pushed by the third screw <NUM> to be discharged through the discharge opening <NUM>.

Claim 1:
A vacuum cracking method for power battery, comprising the following steps:
(<NUM>) feeding waste power batteries from a feed hopper to enter a roller press for rolling treatment to obtain a crushed material;
(<NUM>) transporting the crushed material to the cracking unit for preheating, then heating and cracking the crushed material under an inert atmosphere or vacuum to obtain cracked gas, solid cracked products and non-crackable products; and
(<NUM>) transporting the solid cracked products and the non-crackable products to a pyrolysis unit for pyrolysis at an aerobic atmosphere to obtain pyrolysis gas and non-pyrolysis products, wherein the pyrolysis gas is mainly composed of carbon dioxide and water vapor, and the said non-pyrolysis products are mainly cathode material powder, anode material powder, copper powder, iron powder, aluminum powder and oxides of copper, iron and aluminum.