Patent Application
20170170457
This application claims all benefits accruing under 35 U.S.C. §119 from China Patent Application No. 201410434097.7, filed on Aug. 29, 2014 in the State Intellectual Property Office of China, the content of which is hereby incorporated by reference. This application is a continuation under 35 U.S.C. §120 of international patent application PCT/CN2014/091942, filed on Nov. 21, 2014, the content of which is also hereby incorporated by reference.
The present disclosure relates to powder sintering systems and, particularly, to a powder sintering system under an atmospheric protection condition.
Powder usually refers to a collection of discrete, small solid particles. Airborne powder can cause great harm to those exposed to the airborne powder over a long term. Sintering can fuse the collection of discrete particles into a material or product of crystalline combination, to make effective use of the powder, and reduce environmental pollution.
Powder sintering systems generally involve a static sintering process. In the static sintering process, because the powder is stacked, the sintering temperature difference inside the stacked powder and outside of the stacked powder can be significant. The unevenly mixed powder could result in powder not fully sintered. Thus, the product yield of the powder sintering is relatively low.
Implementations are described by way of example only with reference to the attached figures.
It will be appreciated that for simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein can be practiced without these specific details. In other instances, methods, procedures, and components have not been described in detail so as not to obscure the related relevant feature being described. Also, the description is not to be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale and the proportions of certain parts may be exaggerated to better illustrate details and features of the present disclosure.
Referring to
The furnace body 110 defines a funnel shaped chamber 112 with a closed structure. An upper portion of the furnace body 110 can be a hollow column shaped structure, a hollow cone shaped structure, or a hollow frustum shaped structure, etc. A lower portion of the furnace body 110 can be a hollow frustum shaped structure. In one embodiment, the upper portion of the furnace body 110 has a hollow column shaped structure, and the lower portion of the furnace body 110 has a hollow frustum shaped structure. The hollow column shaped structure and the hollow frustum shaped structure are connected together to form the funnel shaped chamber 112. The hollow column shaped structure can be a hollow cylinder or a hollow prism. The hollow prism can be a hollow quadrangular prism, a hollow pentagonal prism, or a hollow hexagonal prism. The hollow frustum structure can be a hollow conical frustum or a hollow pyramidal frustum, which cooperates with the hollow cylinder or hollow prism. When the hollow prism is a hollow quadrangular prism, a hollow pentagonal prism or a hollow hexagonal prism, the hollow pyramidal frustum can also be quadrangular, pentagonal or hexagonal respectively, to match the shape of the hollow prism.
In one embodiment, the upper portion of the furnace body 110 can be a hollow cylinder, and the lower portion of the furnace body 110 can be a hollow conical frustum. A material of the furnace body 110 can be selected from heat resistance materials. A surface coating layer 114 can be coated on an inner wall of the furnace body 110 to prevent powder from adhering to the inner wall of the furnace body 110 during sintering. The surface coating layer 114 can be a ceramic-based coating, a graphite-based coating, a polytetrafluoroethylene coating, or other high temperature resistant coatings. The surface coating layer 114 can prevent the introduction of metallic impurities such as iron and make the production process cleaner.
The first dispersing device 120 can be configured to centrifugally disperse the powder at the bottom of the furnace body 110 to the side wall of the furnace body 110, thereby improving the mixing of the powder uniformly. That is, the powder is propelled by the spinning of the first dispensing device 120. The number of the first dispersing devices 120 can be one or more according to actual needs. The first dispersing device 120 is located at the bottom of the furnace body 110. In some embodiments, a single first dispersing device 120 is located at a center of the bottom of the furnace body 110. In one embodiment, one first dispersing device 120 is disposed at the center of the bottom surface of the hollow frustum structure.
The second dispersing device 130 can be configured to centrifugally disperse powder at the side wall of the furnace body 110 to the funnel shaped chamber 112. That is, the powder is propelled by the spinning of the second dispensing device 130. In one embodiment, the second dispersing device 130 can disperse the powder from the side wall of the furnace body 110 to a central axis position of the funnel shaped chamber 112. The number of the second dispersing devices 130 can be one or more according to actual needs. The second dispersing device 130 can be located on the side wall of the furnace body 110. In one embodiment, the second dispersing device 130 can be located on the side wall of the furnace body 110 and close to a top of the furnace body 110.
When the number of the second dispersing devices 130 is two or more, the second dispersing devices 130 can be located at the same height or at different heights on the side wall of the furnace body 110. The second dispersing devices 130 can be located opposite each other, opposite each other and offset a certain distance, or provided anywhere along the side wall of the furnace body 100. In one embodiment, the second dispersing devices 130 can be disposed at the same height on the side wall of the furnace body 110. In another embodiment, the second dispersing devices 130 are at the same height on the side wall of the furnace body 110. In yet another embodiment, the second dispersing devices 130 are at the same height opposite to each other as one or more pairs with respect to the central axis of the furnace body 110. The location of the dispersing devices 120, 130 of the powder sintering system 10 can be arranged to be more conducive to adjust and accommodate the movement trajectory of the powder in the furnace body 110. When the second dispersing devices 130 are located at different heights on the sidewall of the furnace body 110, the distribution of the powder can be controlled by adjusting the rotational speed of the two or more second dispersing devices 130 individually. In one embodiment, two second dispersing devices 130 can be disposed at the same height on the side wall of the hollow cylinder, and arranged opposite to each other with respect to the central axis of the funnel shaped chamber 112.
Referring to
The actuator 124 is located outside the furnace body 110 for driving the dispersing wheel 122 to rotate at a constant rotational speed. The actuator 124 can be a magnetically coupled actuator, a motor control actuator, or a mechanical actuator. The circuit controller is connected to the actuator 124 and provides power to the actuator 124. In one embodiment, a rotation axis of the dispersing wheel 122 of the first dispersing device 120 is parallel to a center axis of the funnel shaped chamber 112. The dispersing wheel 122 is a hollow cage type agitator. When the dispersing wheel 122 rotates with a high speed, a negative pressure is generated at the center of the dispersing wheel 122, and the powder can be moved away around the dispersing wheel 122.
The dispersing wheel 122 can comprise a plurality of fins sandwiched between two rings and arranged around an axis of the dispersing wheel 122. The fins can be straight, curved, or specially shaped to engage the powder by striking the powder and propelling the powder away from the dispersing wheel 122. The fins can have a thin profile and be angled radially, tangentially, or both radially and tangentially relative to the axis of the dispersing wheel 122. As shown in
A structure, material, and rotational speed of the second dispersing device 130 can be the same as a structure, material, and rotational speed of the first dispersing device 120 as described above, respectively, except that a rotation axis of the dispersing wheel 122 of the second dispersing device 130 is perpendicular or at an angle to the central axis of the funnel shaped chamber 112.
The heating device 140 includes a heating element 142 and a thermocouple (not shown). The heating element 142 is located outside the furnace body 110 for heating the furnace body 110. The heating device 140 can heat the furnace body 110 to raise the temperature of the funnel shaped chamber 112 within a range from about 100° C. to about 1300° C. . In one embodiment, the heating element 142 of the heating device 140 is a resistance wire wound around an outer surface of the furnace body 110. The thermocouple is located inside the funnel shaped chamber 112 for detecting the temperature of the funnel shaped chamber 112.
In one embodiment, the heating device 140 can further include a protecting layer (not shown) and a thermal insulating layer (not shown). The thermal insulating layer and the protecting layer can be sequent coated on an outer surface of the heating element 142.
The exhaust device 150 is configured to promptly discharge sintered products such as hot smoke and gas in the sintering process. The exhaust device 150 can include a gas-solid separating unit 152, an exhaust pipe 154, an automatic control valve 156, and a gas buffer unit 158. The gas-solid separating unit 152 is located on the top of the furnace body 110 for preventing clogging of the exhaust pipe 154. The gas-solid separating unit 152 can include heat resistance elements such as a gas-solid separator, a filter screen, and a pulsed reverse-inflating element. The gas buffer unit 158 is located on one end of the gas-solid separating unit 152, and the end is away from the furnace body 110. The exhaust pipe 154 is located on one end of the gas buffer unit 158, and the end is away from the furnace body 110. The automatic control valve 156 is disposed on the exhaust pipe 154. The automatic control valve 156 can automatically open the exhaust pipe 154 when the pressure inside the funnel shaped chamber 112 exceeds a set value.
The feed device 160 can be located on the top of the furnace body 110, and capable of feeding powder into a chamber of the furnace body. In one embodiment, the feed device 160 is positioned so that the powder can drop to the bottom of the furnace body 110 by its own weight. The feed device 160 can include a feed pipe 162, a tapered container 164, and a butterfly valve (not shown). The butterfly valve is located between the feed pipe 162 and the tapered container 164. The tapered container 164 is connected to the funnel shaped chamber 112 through the feed pipe 162. The powder can be temporarily stored in the tapered container 164. During the feeding, the powder is transferred from the tapered container 164 into the feed pipe 162 through the butterfly valve, and fed gradually into the funnel shaped chamber 112 through the feed pipe 162.
The discharge device 170 is located on a lower portion of the side wall of the furnace body 110 for discharging the sintered powder from the funnel shaped chamber 112. The discharge device 170 can include a discharge pipe 172 and a control valve 174. The control valve 174 is located on the discharge pipe 172. When the powder is to be discharged after the sintering of the powder is completed, the control valve 174 is opened to discharge the sintered powder out the funnel shaped chamber 112 under the force of gravity, a supply gas, vacuum, or a combination of forces. It is to be understood that the number of feed devices 160 and the discharge device 170 each can be two or more.
The powder sintering system 10 can further include a pressure sensing device 180. The pressure sensing device 180 is used for detecting the gas pressure in the funnel shaped chamber 112. The pressure sensing device 180 can be located on top of the furnace body 110.
The powder sintering system 10 can further include a viewing window (not shown) to facilitate viewing of the state of the powder in the funnel shaped chamber 112. The viewing window can be located on the sidewall or the top of the furnace body 110.
The powder sintering system 10 can be used for preparing a cathode active material or an anode active material of a lithium ion battery, which are mainly lithium transition metal composite oxides, such as lithium iron phosphate, lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, and lithium titanate.
A work principle of the powder sintering system 10 is explained as follows. Powder is temporarily stored in the tapered container 164. When feed of the powder is needed, the powder is transferred into the feed pipe 164 and is gradually fed into the funnel shaped chamber 112 via the feed pipe 164. When the powder reaches the first dispersing device 120 located on the bottom of the furnace body, the powder is dispersed away from the spinning of the first dispensing device 120 by the first dispensing device 120, and propelled to the side wall of the furnace body 110, with the powder spirally raised along the side wall of the furnace body 110. The powder on the side wall of the furnace body 110 is sintered via heating by the heating device 140. If the powder is reaches the second dispersing device 130, the powder is again moved away by the spinning second dispersing device 130 and thrown towards the center of the funnel shaped chamber 112. The tossed powder returns to the first dispensing device 120 falling under the action of its own weight or directly from the second dispersing device 130 and is again propelled and dispersed by the first dispensing device 120, thus forming a cycling process. Therefore, the first dispersing device 120 and the second dispersing device 130 work together to evenly mix the powder and sinter the powder.
The powder sintering system provided in the present disclosure has the following characteristics. First, the dynamic sintering of the powder inside the furnace body can be realized by rationally arranging the dispersing device so that the powder can be uniformly dispersed in the sintering process. Second, in the powder sintering process, only the intake pipe and the feed pipe communicate with the outside environment, which makes the powder sintering system sealed well. Third, the surface coating layer located on the inner wall of the furnace body can avoid the introducing of impurities such as iron during sintering, which make the producing process more clear. In addition, the powder sintering system also has a small occupying space.
Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the embodiments disclosed herein. It is intended that the specification and examples be considered as exemplary only, with the true scope and spirit of the embodiments being indicated by the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201410434097.7 | Aug 2014 | CN | national |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/CN2014/091942 | Nov 2014 | US |
| Child | 15443304 | US |
