Abstract: The present invention relates to a positive electrode active material and a lithium secondary battery including the same, and more particularly, to a positive electrode active material including an overlithiated lithium manganese-based oxide, and capable of preventing the degradation in electrochemical properties of a lithium secondary battery, including rate characteristics, caused by an excess of lithium and manganese in the lithium manganese-based oxide, and particularly reducing side reactions between the lithium manganese-based oxide and a liquid electrolyte during high-voltage operation, and a lithium secondary battery including the same.

Abstract: A fuel cell system includes a fuel cell stack, a valve controlling cooling water to flow to at least one of a cooling line including the fuel cell stack and a radiator and a bypass line different from the cooling line, a heater increasing a temperature of the cooling water, an ion filter removing ions in the cooling water, and a controller determining a starting method of the fuel cell based on an outside air temperature and the temperature of the cooling water at an inlet of the fuel cell stack and determining an opening angle of the valve and an operation of the heater based on the temperature of the cooling water passing through the valve and the temperature of the cooling water passing through a connection line including the ion filter and connected to the cooling line and the bypass line when the starting method is cold start.

Abstract: A fuel cell system includes a coolant control valve to switch a flowing path of a coolant passing through a fluid passage connected to a fuel cell stack, and a controller to control a valve opening amount of the coolant control valve while performing a start sequence previously defined, when a condition for normal start of the fuel cell stack is satisfied, and the coolant control valve is formed by integrating a first valve to switch a flowing path of a coolant flowing into a first pump with a second valve to switch a flowing path of a coolant pumped by the first pump.

Abstract: Described herein is a fuel cell system including a coolant control valve to switch a flowing path of a coolant through a first fluid passage passing through a fuel cell stack and a second fluid passage passing through a cathode oxygen depletion (COD) heater, and a controller to perform a shutdown sequence and control a valve opening amount of the coolant control valve connected to the first fluid passage and the second fluid passage, when shutdown is requested for the fuel cell stack. The coolant control valve is formed by integrating a first valve to switch a flowing path of the coolant flowing into a pump with a second valve to switch a flowing path of a coolant pumped by the pump.

Abstract: There is provided an air supply system and method for a fuel cell, the air supply system includes an air supply device configured to reduce a temperature of compressed air using heat exchange air and to provide the cooled air as power generation air to a fuel cell stack, and an indoor temperature adjustment device configured to provide external air as the heat exchange air to the air supply device or to cool the external air to provide the cooled external air as the heat exchange air to the air supply device, based on operation control information.

Abstract: A battery cooling system includes: a heating element for performing a resistance function of a battery to be subjected to a cooling test; a heating-load controller for controlling a heating load of the heating element according to a thermal model; an environment controller for controlling at least one battery cooling environment parameter such as outdoor temperature and initial temperature; a power supply for applying a current for each evaluation condition by connecting a charger/discharger to the heating element; a cooling processing part for supplying a cooling fluid such as air, coolant, or a refrigerant at a constant temperature and flow rate; and a cooling performance determination part for measuring a temperature of a battery cell over time and determining whether a target performance of the battery is satisfied.