Abstract: A safe charging environment with respect to a flexible battery capable of following the movement of a housing is provided. A flexible battery management system or an electronic device mounted with the flexible battery includes a sensor that senses a movement of the flexible battery and a charge control circuit having a function of starting charging or stopping charging of the flexible battery on the basis of a signal from the sensor; charging of the flexible battery is started using the charge control circuit when the sensor senses the flexible battery in a first mode where the flexible battery is opened and senses the flexible battery in a second mode where the flexible battery is curved.

Abstract: A method for forming a positive electrode active material that can be used for a lithium ion battery having excellent discharge characteristics even in a low-temperature environment is provided. The method includes a first step in which lithium cobalt oxide with a median diameter (D50) of less than or equal to 10 ?m is heated at a temperature higher than or equal to 700° C. and lower than or equal to 1000° C. for longer than or equal to 1 hour and shorter than or equal to 5 hours, a second step in which a first mixture is formed by mixing a fluorine source and a magnesium source to the lithium cobalt oxide subjected to the first step, a third step in which the first mixture is heated at a temperature higher than or equal to 800° C. and lower than or equal to 1100° C.

Abstract: A power storage device that is less likely to be influenced by an ambient temperature is provided. The power storage device capable of being charged and discharged even in a low-temperature environment is provided. A first secondary battery capable of being charged and discharged even at low temperatures and a general second secondary battery are adjacent to each other in the power storage device. The power storage device having such a structure can use, as an internal heat source in a low-temperature environment, heat generated by charge and discharge of the secondary battery capable of being charged and discharged even at low temperatures. Specifically, the power storage device includes the first secondary battery and the second secondary battery adjacent to each other, the first secondary battery has flexibility, and a value of discharge capacity in discharge at ?40° C. is higher than or equal to 50% of a value of discharge capacity in discharge at 25° C.

Abstract: A light-blocking device that includes a display device is provided. A method for unfolding a light-blocking device that includes a display device is provided. The light-blocking device is used for a vehicle. The light-blocking device includes a light-blocking portion, a storage portion, and a driving means. The light-blocking portion includes a display portion on a surface on the inside of the vehicle. The storage portion is positioned in a roof portion of the vehicle. The driving means has a first function of unfolding the light-blocking portion in a first position, a second function of unfolding the light-blocking portion in a second position, and a third function of storing the light-blocking portion in a third position inside the storage portion. The first position is a position where the light-blocking portion does not obstruct driver's forward vision. The second position is a position where the light-blocking portion covers 80% or higher of the area of a windshield of the vehicle.

Abstract: A lithium ion battery having an excellent discharge characteristics even at temperatures below freezing is to be provided. The lithium ion battery includes a positive electrode including a positive electrode active material, an electrolyte, and a negative electrode including a negative electrode active material that is a carbon material. In the lithium ion battery, a value of discharge capacity obtained by, after performing constant current charging at a charge rate of 0.1 C (where 1 C=200 mA/g) until a voltage reaches 4.5 V and then performing constant voltage charging at 4.5 V until a current value achieves 0.01 C in an environment of 25° C., performing constant current discharging at a discharge rate of 0.1 C until a voltage reaches 2.5 V in an environment of ?40° C. is higher than or equal to 50% of a value of discharge capacity obtained by, after performing constant current charging at a charge rate of 0.1 C (where 1 C=200 mA/g) until a voltage reaches 4.

Abstract: Provided is a secondary battery having a favorable interface contact between an active material and an electrolyte. The secondary battery includes a positive electrode layer, a negative electrode layer, and an electrolyte layer positioned between the positive electrode layer and the negative electrode layer. The positive electrode layer contains a positive electrode active material and a first solid electrolyte, the negative electrode layer contains a negative electrode active material and a second solid electrolyte, the electrolyte layer contains a third solid electrolyte and an ionic liquid, and a space in the third solid electrolyte is impregnated with the ionic liquid. The secondary battery is bendable.

Abstract: A secondary battery with little deterioration is provided. A secondary battery with high safety is provided. A separator having excellent characteristics is provided. A separator achieving the secondary battery with high safety is provided. A novel separator is provided. In the separator, a polymer porous film and a layer including a ceramic-based material containing a metal oxide microparticle are stacked, the thickness of the layer including a ceramic-based material is greater than or equal to 1 ?m and less than or equal to 100 ?m, and the film thickness of the polymer porous film is greater than or equal to 4 ?m and less than or equal to 50 ?m.

Abstract: A positive electrode active material having a high charge-discharge capacity and high safety and a secondary battery including the positive electrode active material are provided. The positive electrode active material includes lithium, a transition metal M, an additive element, and oxygen. The powder volume resistivity of the positive electrode active material is higher than or equal to 1.0×105 ?·cm at a temperature of higher than or equal to 180° C. and lower than or equal to 200° C. and at a pressure of higher than or equal to 0.3 MPa and lower than or equal to 2 MPa. The median diameter of the positive electrode active material is preferably greater than or equal to 3 ?m and less than or equal to 10 ?m.

Abstract: A positive electrode and a secondary battery with little deterioration due to charge and discharge are provided. A positive electrode and a secondary battery with high electrode density are provided. Alternatively, a positive electrode and a secondary battery with excellent rate characteristics are provided. The positive electrode contains a positive electrode active material and a coating material. The coating material covers at least part of a surface of the positive electrode active material, and the positive electrode active material contains lithium cobalt oxide containing magnesium, fluorine, aluminum, and nickel. The lithium cobalt oxide includes a region with the highest concentration of one or more selected from the magnesium, the fluorine, and the aluminum in a surface portion. The coating material is preferably one or more selected from glass, carbon black, graphene, and a graphene compound.

Abstract: A positive electrode active material that is stable in a high potential state or a high temperature state and a highly safe secondary battery are provided. The positive electrode includes a first material and a second material and includes a region where at least part of a surface of the first material is covered with the second material. The first material includes a lithium cobalt oxide containing magnesium, fluorine, aluminum, and nickel. The second material includes a composite oxide (containing one or more selected from Fe, Ni, Co, and Mn) having an olivine crystal structure.

Abstract: To increase capacity per weight of a power storage device, a particle includes a first region, a second region in contact with at least part of a surface of the first region and located on the outside of the first region, and a third region in contact with at least part of a surface of the second region and located on the outside of the second region. The first and the second regions contain lithium and oxygen. At least one of the first region and the second region contains manganese. At least one of the first and the second regions contains an element M. The first region contains a first crystal having a layered rock-salt structure. The second region contains a second crystal having a layered rock-salt structure. An orientation of the first crystal is different from an orientation of the second crystal.

Abstract: An active material particle with little deterioration is provided. A positive electrode active material particle with little deterioration is provided. The electrode includes a first particle group, a second particle group, and a third particle group. A median diameter of the first particle group is greater than a median diameter of the third particle group, and a median diameter of the second particle group is between the median diameter of the first particle group and the median diameter of the third particle group. The electrode is formed through a first step of forming a first mixture including the first particle group, the second particle group, the third particle group, and a solvent; a second step of applying the first mixture onto a current collector; and a third step of performing heating to volatilize the solvent.

Abstract: A high-definition liquid crystal display device is provided. A liquid crystal display device with a high aperture ratio is provided. A liquid crystal display device with a high contrast ratio and display quality is provided. A liquid crystal display device capable of being driven at a low voltage is provided. The display device includes, between a pair of substrates, a pixel electrode, a first common electrode, a second common electrode, and a liquid crystal layer. The pixel electrode and the first common electrode are positioned between the liquid crystal layer and one of the substrates. The second common electrode is positioned between the liquid crystal layer and the other substrate. The same potential is supplied to the first common electrode and the second common electrode. The first common electrode includes a portion overlapping with the second common electrode between the display regions of two adjacent subpixels that exhibit different colors.

Abstract: At least part of a fabrication process of a secondary battery is automated. A highly reliable secondary battery is provided.

Abstract: A lithium ion battery having excellent charge characteristics and discharge characteristics even in a low-temperature environment is provided. The lithium ion battery includes a positive electrode active material and an electrolyte. The positive electrode active material contains cobalt, oxygen, magnesium, aluminum, and nickel. The electrolyte contains lithium hexafluorophosphate, ethylene carbonate, ethyl methyl carbonate, and dimethyl carbonate. Second discharge capacity of the lithium ion battery is higher than or equal to 70% of first discharge capacity. The first discharge capacity is obtained by performing first charge and first discharge at 20° C., and the second discharge capacity is obtained by performing second charge and second discharge at ?40° C. The first discharge and the second discharge are constant current discharge with 20 mA/g per positive electrode active material weight.

Abstract: At least part of a fabrication process of a secondary battery is automated. A highly reliable secondary battery is provided. The secondary battery is fabricated by placing a first electrode over a first exterior body; placing a separator over the first electrode; placing a second electrode over the separator; dripping an electrolyte on at least one of the first electrode, the separator, and the second electrode; impregnating the at least one of the first electrode, the separator, and the second electrode with the electrolyte; then placing a second exterior body over the first exterior body to cover the first electrode, the separator, and the second electrode; and sealing the first electrode, the separator, and the second electrode with the first exterior body and the second exterior body. The electrolyte is dripped from a position whose shortest distance from a surface where the electrolyte is dripped is greater than 0 mm and less than or equal to 1 mm.

Abstract: One embodiment of the present invention achieves a fabrication method that can automate fabrication of a secondary battery. In addition, a fabrication method that can fabricate a secondary battery efficiently in a short time is achieved. Furthermore, a fabrication method that can fabricate a secondary battery with high yield is achieved. Alternatively, a method for fabricating a large secondary battery with a relatively large size is achieved. An electrolyte is dripped on one or more of a positive electrode, a separator, and a negative electrode; the one or more of the positive electrode, the separator, and the negative electrode are impregnated with the electrolyte; pressure is then reduced; and a stack of the positive electrode, the separator, and the negative electrode is sealed with an exterior film.

Abstract: A high-definition liquid crystal display device is provided. A liquid crystal display device with a high aperture ratio is provided. A liquid crystal display device with a high contrast ratio and display quality is provided. A liquid crystal display device capable of being driven at a low voltage is provided. The display device includes, between a pair of substrates, a pixel electrode, a first common electrode, a second common electrode, and a liquid crystal layer. The pixel electrode and the first common electrode are positioned between the liquid crystal layer and one of the substrates. The second common electrode is positioned between the liquid crystal layer and the other substrate. The same potential is supplied to the first common electrode and the second common electrode. The first common electrode includes a portion overlapping with the second common electrode between the display regions of two adjacent subpixels that exhibit different colors.

Abstract: To increase capacity per weight of a power storage device, a particle includes a first region, a second region in contact with at least part of a surface of the first region and located on the outside of the first region, and a third region in contact with at least part of a surface of the second region and located on the outside of the second region. The first and the second regions contain lithium and oxygen. At least one of the first region and the second region contains manganese. At least one of the first and the second regions contains an element M. The first region contains a first crystal having a layered rock-salt structure. The second region contains a second crystal having a layered rock-salt structure. An orientation of the first crystal is different from an orientation of the second crystal.

Abstract: To increase capacity per weight of a power storage device, a particle includes a first region, a second region in contact with at least part of a surface of the first region and located on the outside of the first region, and a third region in contact with at least part of a surface of the second region and located on the outside of the second region. The first and the second regions contain lithium and oxygen. At least one of the first region and the second region contains manganese. At least one of the first and the second regions contains an element M. The first region contains a first crystal having a layered rock-salt structure. The second region contains a second crystal having a layered rock-salt structure. An orientation of the first crystal is different from an orientation of the second crystal.