1. A modular indefinite volume combined tank, comprising:a tank body module, a tank bottom module and an inflating module;
wherein the tank body module is formed by splicing a plurality of wall plates and connectors, the wall plates are strip plates, four sides of the plates are arranged with four frames, and two frames of the four frames in a direction parallel to the strip plates are arranged with a connector, the connector is of a dumbbell structure; the connector includes a fixing bolt, an inner connecting piece and an outer connecting piece, coaxial through-holes are arranged in the middle of the outer connecting piece and inner connecting piece, the fixing bolt passes through the through-hole of the outer connecting piece and inner connecting piece for fixed connection, the outer connecting piece is of a dumbbell shape, the inner connecting piece is of a groove shape, the gap between the outer connecting piece and inner connecting piece is wide in the middle and narrow at both ends, the connector is fixed in the outer connecting piece and inner connecting piece, in order to realize the function that the connector fixes two adjacent wall plates; an annular tank body is formed by n wall plates and n-1 connectors;
the tank bottom module comprises a strip-shape steel plate, concrete cloth, annular steel plate and a cement foundation, wherein the cement foundation is structured such that a round region is poured on the ground through cement; the strip-shape steel plate is paved on the cement foundation, the strip-shape steel plate is of a strip structure, the edge of the strip-shape steel plate is arc-shaped, all strip-shape steel plates form a steel plate area of a circular structure, the annular steel plate is arranged in the upper side of the outer edge of the strip-shape steel plate, the annular steel plate is encircled by a plurality of arc-shaped steel sheets, a ring of annular edge is arranged in the annular steel plate to be connected to the upper tank body, and a layer of concrete cloth is arranged between the lower side of the annular steel plate and the strip-shape steel plate; and
the inflating module comprises a top cover and a liner, wherein the top cover is an inflated cover having a shape of a pot cover, a cylindrical liner is connected below the top cover, the liner is also of an inflated structure, inflating layers are arranged in the liner and the top cover, the bottom of the liner is arranged with a liquid inlet/outlet, the wall plate corresponding to the liquid inlet/outlet is arranged with an opening, the liquid inlet/outlet of the liner is arranged with quick coupling; an acid or alkali resistant layer is arranged inside the liner and the top cover; the contact between the top cover and the liner is arranged with an inflating port, the wall plate corresponding to a side face of the inflating port is arranged with an opening, and the opening is arranged with inflating connector.