Electrical connection box

1. An electrical connection box comprising:

a box main body having one surface on which a plurality of component mounting portions in which electrical components are to be mounted are provided;

a cover member for covering the one surface of the box main body; and

a lock mechanism including a locked portion provided on a peripheral wall portion of the box main body and an elastic lock portion provided in a cantilever shape on the cover member,

wherein the cover member includes a frame body peripheral wall portion on which the elastic lock portion is integrally provided and the top wall portion that is formed separately from the frame body peripheral wall portion and is detachably attached and fixed to the frame body peripheral wall portion, and

wherein the top wall portion of the cover member is made of a resin material with a greater thermal conductivity than the elastic lock portion provided on the frame body peripheral wall portion of the cover member, and the elastic lock portion provided on the frame body peripheral wall portion of the cover member is made of a resin material with a greater elasticity than the top wall portion of the cover member.

2. The electrical connection box according to claim 1 , wherein the entire frame body peripheral wall portion is made of a resin material with a greater elasticity than the top wall portion.

3. The electrical connection box according to claim 1 , wherein

the top wall portion is attached and fixed by being inserted into the frame body peripheral wall portion from a lower-side opening portion of the frame body peripheral wall portion that opposes the box main body side,

an inner flange is provided protruding on an upper-side opening portion of the frame body peripheral wall portion that is spaced apart from the box main body, and an insertion end of the top wall portion is defined due to an outer peripheral edge portion of the top wall portion overlapping with the inner flange,

a lock piece that can perform bending deformation outward in a plate thickness direction is provided on the frame body peripheral wall portion, insertion of the top wall portion into the frame body peripheral wall portion is allowed due to the lock piece performing bending deformation outward upon abutting on a lock protruding portion provided protruding on a peripheral wall of the top wall portion, and due to the lock piece going past the lock protruding portion and elastically returning, the lock piece and the lock protruding portion engage with each other and the top wall portion is held in the frame body peripheral wall portion, and

a water entrance prevention wall that is located on an outer periphery side with respect to an abutting surface abutting on the box main body and protrudes downward is provided protruding on a lower-side opening portion of the peripheral wall of the top wall portion.

4. The electrical connection box according to claim 3 , wherein

the peripheral wall portion of the box main body has a double-wall structure including an inner peripheral wall portion that abuts on and holds the abutting surface of the top wall portion that abuts on the box main body, and an outer peripheral wall portion that abuts on and holds an abutting surface of the frame body peripheral wall portion that abuts on the box main body, and the water entrance prevention wall is inserted into a recessed groove provided between the inner peripheral wall portion and the outer peripheral wall portion.