Pixel circuit and driving method thereof, display substrate, and display device

A pixel circuit, comprising:

• a gate line, a data line, a first charging sub-circuit, a second charging sub-circuit and a display sub-circuit;
• the first charging sub-circuit is configured to be controllable to output a data signal from the data line to a charging node and to store the data signal from the data line, wherein the first charging sub-circuit comprises a first transistor and a storage capacitor, a gate of the first transistor is connected to a control line;
• or the first charging sub-circuit comprises at least two charging sub-sub-circuits connected in series and each charging sub-sub-circuit comprises the first transistor and the storage capacitor, a gate of the first transistor in each charging sub-sub-circuit is respectively connected to a plurality of control lines;
• and
• the second charging sub-circuit is respectively connected to the charging node, the gate line and the display sub-circuit, and is configured to be controllable to output a data signal from the charging node to the display sub-circuit, wherein the second charging sub-circuit comprises a second transistor, a gate of the second transistor is connected to the gate line;
• and
• the display sub-circuit comprises a liquid crystal capacitor,
• wherein a process of charging the liquid crystal capacitor by the first charging sub-circuit and the second charging sub-circuit comprises two periods:
• in a first charging period, when the control line provides a gate driving signal of a first voltage level, the first transistor is turned on under action of the gate driving signal, and the data line charges the storage capacitor through the first transistor;
• in a second charging period, when the gate line provides the gate driving signal of the first voltage level, the second transistor is turned on under action of the gate driving signal, and the storage capacitor charges the liquid crystal capacitor through the second transistor, wherein when the control line provides a gate driving signal of a second voltage level, the first transistor is turned off, the charging node is disconnected from the data line,
• wherein after the second charging period, when the gate driving signal provided by the gate line jumps to the second voltage level, the second transistor is turned off, and the charging node is disconnected from the liquid crystal capacitor.