Abstract: A silicon-based negative active material that includes a core including silicon oxide represented by SiOx (0<x<2); and a coating layer including metal oxide, and the metal of the metal oxide includes aluminum (Al), titanium (Ti), cobalt (Co), magnesium (Mg), calcium (Ca), potassium (K), sodium (Na), boron (B), strontium (Sr), barium (Ba), manganese (Mn), nickel (Ni), vanadium (V), iron (Fe), copper (Cu), phosphorus (P), scandium (Sc), zirconium (Zr), niobium (Nb), chromium (Cr), and/or molybdenum (Mo), the core has a concentration gradient where an atom % concentration of a silicon (Si) element decreases to the center of the core, and an atom % concentration of an oxygen (O) element increases to the center, and a depth from the surface contacting the coating layer where a concentration of the silicon (Si) element is about 55 atom % corresponds to about 2% to about 20% of a diameter of the core.

Abstract: A method of manufacturing a curved secondary battery, the method including preparing a flat secondary battery such that the flat secondary battery includes an electrode assembly and a pouch accommodating the electrode assembly; primary shaping the secondary battery such that the primary shaping includes disposing the flat secondary battery in a first jig, and pressing the flat secondary battery to form a primarily-shaped secondary battery such that the primarily-shaped secondary battery has a first curvature radius; secondary shaping the secondary battery such that the secondary shaping includes disposing the primarily-shaped secondary battery in a second jig, and pressing the primarily-shaped secondary battery to form a secondarily-shaped secondary battery having a second curvature radius; and maintaining the secondarily-shaped secondary battery after forming thereof in the second jig for a predetermined time period.

Abstract: Provided is a laser cutting device and method which changes a cutting speed of a laser according to a difference between characteristics (absorption coefficients) of an object to be cut, so as to uniformly supply an energy of laser to the whole of the object, thereby preventing the object from being incompletely cut. A laser cutting device includes a database that stores information about a cutting pattern, a moving part that changes a location of a laser beam emitted to an object to be cut, a characteristic value input part that receives speed information from a user according to locations on the cutting pattern, and a control part that adjusts a moving speed of the laser beam by controlling the moving part according to the speed information from the characteristic value input part, and the information about the cutting pattern from the data base.

Abstract: Provided is a unit stacking device for a secondary battery, which stacks one or more first radical units having a first size and one or more second radical units having a second size greater than the first size and includes a stack jig, which includes a first inner space having a size corresponding to the first size and a second inner space disposed above the first inner space and communicating with the first inner space and having a size corresponding to the second size. The first radical units are stacked in the first inner space through the second inner space, and then, the second radical units are stacked in the second inner space.

Abstract: An electrode assembly according to an embodiment of the present invention includes a first electrode plate having a fist electrode tab at an end of one side thereof, a second electrode plate having a second electrode tab, which is formed in a same direction as a longitudinal direction of the first electrode tab and is formed at a position not overlapping the first electrode tab, and a protrusion which is formed at a position overlapping the fist electrode tab, and a separator insulating the first electrode plate and the second electrode plate. Therefore, the electrode assembly according to the embodiment of the present invention and the secondary battery including the same may improve the stability of the secondary battery by preventing lithium ion accumulation in a separator.

Abstract: An electrode assembly includes a cell stack part having (a) a structure in which one kind of radical unit having a same number of electrodes and separators alternately disposed and integrally combined is repeatedly disposed, or (b) a structure in which at least two kinds of radical units having a same number of electrodes and separators alternately disposed and integrally combined are disposed in a predetermined order, and a fixing part extending from a top surface along a side to a bottom surface thereof for fixing the cell stack part. The one kind of radical unit has a four-layered structure in which first electrode, first separator, second electrode and second separator are sequentially stacked or a repeating structure in which the four-layered structure is repeatedly stacked, and each of the at least two kinds of radical units are stacked by ones to form the four-layered structure or the repeating structure.

Abstract: Provided is a gripper assembly for battery charging/discharging, which is electrically connected to a battery electrode to apply current during battery charging/discharging operation, the gripper assembly including a first electrode lead gripper including a first electrode gripper body disposed to correspond to a first electrode lead of the battery, and a first contact member coupled to one side of the first electrode gripper body and pressed to contact a surface of the first electrode lead and a second electrode lead gripper including a second electrode gripper body disposed to correspond to a second electrode lead of the battery, and a second contact member coupled to a side of the second electrode gripper body and attached to contact a surface of the second electrode lead.

Abstract: Provided are a method for compensating instantaneous power failure in medium voltage inverter and a medium voltage inverter system by using the same, the method for compensating instantaneous power failure in medium voltage inverter including a plurality of power cells supplying a phase voltage to a motor by being connected to the motor in series, the method including decreasing an output frequency of the plurality of power cells by as much as a predetermined value at a relevant point where an input voltage of the plurality of power cells is less than a reference value, decreasing the output frequency at a predetermined deceleration gradient, and maintaining the output frequency during restoration of input voltage as long as a predetermined time, in a case the input voltage is restored.

Abstract: An electrode assembly includes a cell stack part having a structure of steps obtained by stacking at least two groups of radical units having different sizes or having different geometric shapes according to the size or the geometric shapes. The radical unit has a combined structure into one body by alternately same number of electrodes and separators, and each step of the cell stack part has a structure in which one kind of radical units is disposed once or repeatedly, or a structure in which at least two kinds of radical units are disposed. The one kind of radical unit has a four-layered structure of first electrode, first separator, second electrode and second separator sequentially stacked or a repeating structure of the four-layered structure. Each of the at least two kinds of radical units are stacked by ones to form the four-layered structure or the repeating structure.

Abstract: An electrode assembly includes a cell stack part having (a) a structure in which one kind of radical unit is repeatedly disposed, or (b) a structure in which at least two kinds of radical units are disposed in a predetermined order. The one kind of radical unit has a four-layered structure in which first electrode, first separator, second electrode and second separator are sequentially stacked or a repeating structure in which the four-layered structure is repeatedly stacked. Each of the at least two kinds of radical units are stacked by ones to form the four-layered structure or the repeating structure. The separator has a larger size than the electrode to expose an edge part of the separator to outside of the electrode and the separator. The edge parts of the separators included in one radical unit or in the cell stack part are attached to form a sealing part.

Abstract: An electrode assembly includes a cell stack part having (a) a structure in which one kind of radical unit is repeatedly disposed and has same number of electrodes and separators which are alternately disposed and integrally combined, or (b) a structure in which at least two kinds of radical units are disposed in a predetermined order, and an auxiliary unit disposed on at least one among an uppermost part or a lowermost part of the cell stack part. The one kind of radical unit of (a) has a four-layered structure in which a first electrode, a first separator, a second electrode and a second separator are sequentially stacked or a repeating structure in which the four-layered structure is repeatedly stacked, and each of the at least two kinds of radical units are stacked by ones in the predetermined order to form the four-layered structure or the repeating structure.

Abstract: A silicon-based negative active material that includes a core including silicon oxide represented by SiOx (0<x<2); and a coating layer including metal oxide, and the metal of the metal oxide includes aluminum (Al), titanium (Ti), cobalt (Co), magnesium (Mg), calcium (Ca), potassium (K), sodium (Na), boron (B), strontium (Sr), barium (Ba), manganese (Mn), nickel (Ni), vanadium (V), iron (Fe), copper (Cu), phosphorus (P), scandium (Sc), zirconium (Zr), niobium (Nb), chromium (Cr), and/or molybdenum (Mo), the core has a concentration gradient where an atom % concentration of a silicon (Si) element decreases to the center of the core, and an atom % concentration of an oxygen (O) element increases to the center, and a depth from the surface contacting the coating layer where a concentration of the silicon (Si) element is about 55 atom % corresponds to about 2% to about 20% of a diameter of the core.

Abstract: Provided are a method for compensating instantaneous power failure in medium voltage inverter and a medium voltage inverter system by using the same, the method for compensating instantaneous power failure in medium voltage inverter including a plurality of power cells supplying a phase voltage to a motor by being connected to the motor in series, the method including decreasing an output frequency of the plurality of power cells by as much as a predetermined value at a relevant point where an input voltage of the plurality of power cells is less than a reference value, decreasing the output frequency at a predetermined deceleration gradient, and maintaining the output frequency during restoration of input voltage as long as a predetermined time, in a case the input voltage is restored.

Abstract: A rechargeable lithium battery, which includes: a negative electrode including a silicon-based negative active material; a positive electrode (including a positive active material capable of intercalating and deintercalating lithium, and a conductive material including a fiber shaped material and a non-fiber shaped material), wherein a weight per unit area of the positive electrode (which is a loading level (LL) of the positive electrode) is about 20 mg/cm2 to 100 mg/cm2; and a non-aqueous electrolyte.

Abstract: A rotation speed search apparatus for an induction motor includes: a voltage control unit for comparing a rated current of a motor and a current detected from the motor and generating an output voltage; and a frequency control unit for comparing a reference excitation current of the motor and an excitation current detected from the motor and generating an output frequency. In case of a big load, an output frequency is reduced. Thus, the slip of the motor is moved to a slip where a maximum torque is generated to enable the induction motor to start. If the speed of the motor in operation is greater than a target frequency, an output frequency is increased, so that the motor can be operated even in the regenerative region of the motor.

Abstract: A motor torque control apparatus and method are disclosed. By adding the value of the compensation voltage which is obtained by proportionally integrating a difference value between the predetermined reference magnetic flux component current value and the actually measured magnetic flux component current value to the q-axis instructing voltage, the magnetic flux component current, that is, the excitation current, can be constantly controlled without excess or shortage. In addition, since the magnetic flux is constantly controlled irrespective of the speed of the motor, a high torque can be generated even at the initial stage of starting of the motor (at the low speed), and thus, the torque of the motor can be smoothly controlled in every operation range from a low speed to a high speed.

Abstract: A rotation speed search apparatus for an induction motor includes: a voltage control unit for comparing a rated current of a motor and a current detected from the motor and generating an output voltage; and a frequency control unit for comparing a reference excitation current of the motor and an excitation current detected from the motor and generating an output frequency. In case of a big load, an output frequency is reduced. Thus, the slip of the motor is moved to a slip where a maximum torque is generated to enable the induction motor to start. If the speed of the motor in operation is greater than a target frequency, an output frequency is increased, so that the motor can be operated even in the regenerative region of the motor.

Abstract: A motor torque control apparatus and method are disclosed. By adding the value of the compensation voltage which is obtained by proportionally integrating a difference value between the predetermined reference magnetic flux component current value and the actually measured magnetic flux component current value to the q-axis instructing voltage, the magnetic flux component current, that is, the excitation current, can be constantly controlled without excess or shortage. In addition, since the magnetic flux is constantly controlled irrespective of the speed of the motor, a high torque can be generated even at the initial stage of starting of the motor (at the low speed), and thus, the torque of the motor can be smoothly controlled in every operation range from a low speed to a high speed.

Abstract: A sensorless vector control apparatus includes a speed controller for receiving a speed command value from a user and outputting a synchronous speed; a ‘d’ and ‘q’ axis voltage command unit for receiving the synchronous speed and outputting a ‘d’ axis voltage and a ‘q’ axis voltage; a voltage converter for receiving the ‘q’ axis voltage and the ‘d’ axis voltage, and converting the two phase voltages into three phase voltages; and an inverter for receiving the three phase voltages and controlling a speed of an induction motor. Since the vector control may be performed over the whole velocity range without using a speed sensor, the sensorless vector control apparatus may be used with advantage.

Abstract: A sensorless vector control apparatus includes a speed controller for receiving a speed command value from a user and outputting a synchronous speed; a ‘d’ and ‘q’ axis voltage command unit for receiving the synchronous speed and outputting a ‘d’ axis voltage and a ‘q’ axis voltage; a voltage converter for receiving the ‘q’ axis voltage and the ‘d’ axis voltage, and converting the two phase voltages into three phase voltages; and an inverter for receiving the three phase voltages and controlling a speed of an induction motor. Since the vector control is possibly performed in the whole velocity range even without using a speed sensor, the sensorless vector control apparatus can be manufactured to a product. In addition, since the amount of arithmetic operation for implementing an algorithm is not much, the algorithm can be implemented even with the general CPU or DSP.