Abstract: A pipeline-type positive warp yarn feeding device includes a yarn bobbin frame and a yarn feeding frame. The yarn feeding frame is provided with a positive yarn feeding assembly including a positive yarn feeding power component and positive yarn feeding wheels on the yarn feeding frame, the positive yarn feeding wheels correspond to yarn bobbins on the yarn bobbin frame, an outer circumference surface of a wheel shaft of each positive yarn feeding wheel defines spiral yarn feeding grooves, a groove mouth width of each yarn feeding groove is matched with a width of a strand of yarn, the yarn on the yarn bobbins is wound on the positive yarn feeding wheels, each yarn feeding groove accommodates a single strand of the yarn, and the positive yarn feeding power component is configured to drive the positive yarn feeding wheels to rotate and feed the yarn through a transmission gear assembly.

Abstract: Disclosed is a carbon fiber preform, a preparation method therefor and a preparation method for carbon/carbon composites, falling within the technical field of composites. The carbon fiber preform provided by the present disclosure includes a plurality of stacked carbon fiber cloths and prestressed layers arranged between every two of adjacent carbon fiber cloths, the prestressed layer including a boron-containing phenol-formaldehyde resin coating and carbon fiber bundles distributed within the boron-containing phenol-formaldehyde resin coating. In the present disclosure, the prestressed layers are formed by adding the carbon fiber bundles and a boron-containing phenol-formaldehyde resin precursor to a two dimensional (2D) stacked preform, thereby counteracting internal stresses during carbonization and obtaining a carbon/carbon composite having higher strength and being less prone to cracking.

Abstract: The present disclosure provides a cooling control method and a cooling control apparatus for a generator of a wind turbine. A cooling device of the generator and an intermittent operation device are connected to a frequency converter, the frequency converter controls the cooling device and the intermittent operation device to start up at different times, and the cooling control method includes: under a condition that a starting condition of the intermittent operation device is determined to be satisfied, calculating a predicted temperature of the generator; under a condition that the predicted temperature is less than or equal to a predetermined threshold temperature, using the frequency converter to control the intermittent operation device to start up to execute the predetermined related action; and using the frequency converter to control the cooling device to start up to cool the generator.

Abstract: A handheld electric hair drier comprising a main body including a primary fluid inlet, a primary fluid outlet, a fan unit, a heating element, and a fluid flow path, and a handle. The fluid flow path comprises a primary fluid flow path that extends from the main body to the primary fluid outlet along a straight line, a side fluid flow path, and a wall-defined fluid flow path. Air fluid drawn through the side fluid flow path and the wall-defined path enters the fan unit through the primary fluid flow path. The fan unit is arranged on the primary fluid flow path, and the fan unit sucks fluid into the primary fluid flow path and transmits the fluid to pass through the heating element, so that the fluid in the primary fluid flow path is heated. The hair drier can provide high-pressure jet airflow and improve the air supplementing speed.

Abstract: An oxide composite positive electrode material coated with borate in situ, includes ?AxByOz—NaaLibNicCudMneMfO2+?. In the material, Li, Ni, Cu, Mn, and element M for doping and substituting a transition metal site together occupy the position of transition metal ions in the crystal structure. The space group of the layered oxide composite positive electrode material is P63/mmc or P63/mcm or R3m, or the corresponding structure is a P2 phase or an O3 phase. AxByOz is a coating layer that has a needle-like structure and is generated in situ on the surface of NaaLibNicCudMneMfO2+?, being formed by, during a sintering process, coating a material precursor and a layered oxide precursor for generating NaaLibNicCudMneMfO2+?; ? is the mass fraction of the coating material precursor in the layered oxide precursor, 0.1 wt %???10 wt %; and A is Li and/or Na.

Abstract: An electrode sheet, a battery cell, and a battery are provided. The electrode sheet includes an electrode sheet body. The electrode sheet body includes a first side edge and a second side edge connected. A connection position between the first side edge and the second side edge is provided with a first chamfer. The first chamfer includes a first arc segment and at least one first transition segment. The first arc segment is connected to the first side edge and/or the second side edge through the at least one first transition segment. The first arc segment protrudes toward a direction away from a center of the electrode sheet body.

Abstract: Disclosed is a carbon fiber preform, a preparation method therefor and a preparation method for carbon/carbon composites, falling within the technical field of composites. The carbon fiber preform provided by the present disclosure includes a plurality of stacked carbon fiber cloths and prestressed layers arranged between every two of adjacent carbon fiber cloths, the prestressed layer including a boron-containing phenol-formaldehyde resin coating and carbon fiber bundles distributed within the boron-containing phenol-formaldehyde resin coating. In the present disclosure, the prestressed layers are formed by adding the carbon fiber bundles and a boron-containing phenol-formaldehyde resin precursor to a two dimensional (2D) stacked preform, thereby counteracting internal stresses during carbonization and obtaining a carbon/carbon composite having higher strength and being less prone to cracking.

Abstract: The present disclosure provides a cooling control method and a cooling control apparatus for a generator of a wind turbine. A cooling device of the generator and an intermittent operation device are connected to a frequency converter, the frequency converter controls the cooling device and the intermittent operation device to start up at different times, and the cooling control method includes: under a condition that a starting condition of the intermittent operation device is determined to be satisfied, calculating a predicted temperature of the generator; under a condition that the predicted temperature is less than or equal to a predetermined threshold temperature, using the frequency converter to control the intermittent operation device to start up to execute the predetermined related action; and using the frequency converter to control the cooling device to start up to cool the generator.

Abstract: A high voltage ride through (HVRT) device and method, a wind power converter, and a wind turbine set. The HVRT device comprises: an unloading module (200), which comprises a brake module (220) and a first switching element (210) that form a series connection with one another, and which is configured to discharge energy when a HVRT occurs; a controller (100), which is configured to detect a direct current (DC) bus voltage so as to control the first switching element (210) to be turned on when a HVRT occurs and the DC bus voltage is greater than a first threshold and less than or equal to a second threshold, such that the brake module (220) inputs and discharges energy; and a passive driving circuit (400), which applies a turn-on signal to a control terminal of the first switching element (210) by using the DC bus voltage in response to the DC bus voltage being greater than the second threshold, such that the brake module (220) inputs and discharges energy.

Abstract: The present disclosure provides a square battery and a welding method. The square battery includes: a cover plate provided with a pole; and a core provided with a tab, where the tab is directly connected to the pole by laser welding, so that construction of an energy transmission path of the battery is realized, and a charging and discharging function of the core is realized. Additionally, since the tab of the core of the square battery is directly connected to the cover plate of the square battery, an auxiliary welding sheet and a connection sheet are removed, thereby improving the internal space utilization rate and the mass specific energy of the square battery.

Abstract: A battery cover includes a top cover assembly and an insulating support. The top cover assembly can be fixedly connected with a case to form an accommodation space for accommodating a core, and the top cover assembly can be welded with a tab on the core. The insulating support can be accommodated in the accommodation space. The insulating support and the top cover assembly form an accommodation cavity for accommodating the tab, and the insulating support is provided with a notch for the tab to pass through.

Abstract: A battery cover includes a top cover assembly and an insulating support. The top cover assembly can be fixedly connected with a case to form an accommodation space for accommodating a core, and the top cover assembly can be welded with a tab on the core. The insulating support can be accommodated in the accommodation space. The insulating support and the top cover assembly form an accommodation cavity for accommodating the tab, and the insulating support is provided with a notch for the tab to pass through.

Abstract: Disclosed in the present application is a self-heating structure and a battery pack including the same. The self-heating structure includes a heating member, including a heating body and a connection lead molded on the heating body, the connection lead being used for electrically connecting a positive electrode tab of a core pack or a negative electrode tab of the core pack, so that a self-heating circuit is formed by the heating member and the core pack; and a control unit, controlling an on/off switching of the self-heating circuit according to temperature of the core pack, the control unit being provided on the connection lead to integrate the control unit and the connection lead.

Abstract: An electrode thickness control method and a control system is provided. The control method includes: obtaining an initial thickness and a target thickness of a to-be-rolled electrode; controlling, according to the initial thickness and the target thickness, a target device to roll the to-be-rolled electrode; obtaining first thickness change data of the to-be-rolled electrode, second thickness change data of a rolled electrode formed through rolling, and current rolling speed data of the target device; and adjusting, according to the first thickness change data, the second thickness change data, or the current rolling speed data, a current rolling pressure or a current rolling temperature of the target device, to cause a thickness of the rolled electrode to reach the target thickness.

Abstract: The present application provides a wind turbine and a converter filter capacitor switching control method, device and system therefor. The method includes: acquiring a contactor delay influence factor of the converter and an approximate zero voltage period of the power grid connected to the wind turbine, wherein an absolute value of a voltage of the power grid in the approximate zero voltage period is less than an approximate zero voltage threshold; obtaining a contactor delay duration according to the contactor delay influence factor, wherein the contactor delay duration is a duration from when the contactor receives a switching instruction to when the contactor is switched on or off; determining a switching time point of the filter capacitor based on the approximate zero voltage period and the contactor delay duration; transmitting the switching instruction to the contactor when the switching time point is reached.

Abstract: Embodiments of the present disclosure are a pitch-based negative electrode material for a sodium-ion battery and related methods and applications. The method comprises: placing a pitch recursor into a muffle furnace to allow the pitch precursor to experience pre-oxidation for 2 to 6 hours at a temperature ranging from 200° C. to 350° C., to obtain pre-oxidized pitch; placing the pre-oxidized pitch into a high-temperature carbonization furnace, and increasing the temperature to 1300° C. to 1600° C. at a temperature increase speed of 0.5° C./min to 5° C./min, and carrying out thermal treatment on the pre-oxidized pitch in an inert atmosphere for 1 to 10 hours, to allow the pre-oxidized pitch to experience carbonization reactions, oxygen in the pre-oxidized pitch being used for breaking an ordered structure of the pitch during the carbonization of the pre-oxidized pitch, so as to form a wedge-shaped voids disordered structure.

Abstract: A handheld electric hair drier comprising a main body including a primary fluid inlet, a primary fluid outlet, a fan unit, a heating element, and a fluid flow path, and a handle. The fluid flow path comprises a primary fluid flow path that extends from the main body to the primary fluid outlet along a straight line, a side fluid flow path, and a wall-defined fluid flow path. Air fluid drawn through the side fluid flow path and the wall-defined path enters the fan unit through the primary fluid flow path. The fan unit is arranged on the primary fluid flow path, and the fan unit sucks fluid into the primary fluid flow path and transmits the fluid to pass through the heating element, so that the fluid in the primary fluid flow path is heated. The hair drier can provide high-pressure jet airflow and improve the air supplementing speed.

Abstract: A carbon-based anode material with high ramp capacity, a preparation method therefore, and a use thereof. The method includes placing a carbon source precursor into a crucible and heating to 400° C-1000° C. at a heating rate of 0.2° C./min-30° C./min under an inert atmosphere, wherein the precursor includes any one or a combination of at least two of fossil fuel, biomass, resin, and organic chemicals; and carrying out heat treatment on the precursor at a temperature of 400° C. to 1000° C. for 0.5-48 hours to carbonize the precursor to obtain a carbon-based negative electrode material. The specific surface area of the anode material is less than 10 m2/g. and assembling the obtained electrode material into a sodium ion battery and then carrying out charging and discharging between 0 and 2.5 V, to obtain a voltage curve. The ramp capacity being above 180 mAh/g and the first-cycle Coulombic efficiency is above 75%.

Abstract: Embodiments of the present disclosure are a pitch-based negative electrode material for a sodium-ion battery and related methods and applications. The method comprises: placing a pitch recursor into a muffle furnace to allow the pitch precursor to experience pre-oxidation for 2 to 6 hours at a temperature ranging from 200° C. to 350° C., to obtain pre-oxidized pitch; placing the pre-oxidized pitch into a high-temperature carbonization furnace, and increasing the temperature to 1300° C. to 1600° C. at a temperature increase speed of 0.5° C./min to 5° C./min, and carrying out thermal treatment on the pre-oxidized pitch in an inert atmosphere for 1 to 10 hours, to allow the pre-oxidized pitch to experience carbonization reactions, oxygen in the pre-oxidized pitch being used for breaking an ordered structure of the pitch during the carbonization of the pre-oxidized pitch, so as to form a wedge-shaped voids disordered structure.

Abstract: The invention discloses a sodium ion secondary battery anode material, and a preparing method and application thereof. The material is an amorphous carbon material, and is obtained by performing high-temperature pyrolyzing on coal as a main raw material, the material is prepared by using coal and a hard carbon precursor as raw materials, mechanical mixing after adding a solvent, drying, and crosslinking, curing and pyrolyzing under an inert gas atmosphere, or prepared by using coal as a raw material, and pyrolyzing under an inert gas atmosphere. The sodium ion secondary battery prepared from the amorphous carbon material as anode material has lower cost and higher work voltage, and is stable in cycle and good in safety.