An electric vehicle chassis comprising: an underbody panel located below a cabin of an electric vehicle; two side sills extending along the longitudinal direction of the underbody panel, wherein each of the two side sills comprises an upper part and a lower part and is connected to one of the two opposite sides of the underbody panel through the upper part thereof; a battery pack located below the underbody panel and between the two side sills, comprising: a plurality of battery modules; a support part provided with a bottom for supporting the plurality of battery modules, sides, a top, and an accommodation space formed by the bottom, the sides, and the top for accommodating the plurality of battery modules; at least one opening provided on either the bottom or sides of the support part to enable the plurality of battery modules to be passed through the at least one opening and be detachably mounted to either the bottom or sides of the support part so as to be supported by either the bottom or sides; and a carbon fibre composite layer of refractory material mounted above the top of the support part to cover the plurality of battery modules accommodated in the support part; and wherein the battery pack is configured to be mounted to the lower parts of the two side sills through the bottom of the support part. an underbody panel located below a cabin of an electric vehicle; two side sills extending along the longitudinal direction of the underbody panel, wherein each of the two side sills comprises an upper part and a lower part and is connected to one of the two opposite sides of the underbody panel through the upper part thereof; a battery pack located below the underbody panel and between the two side sills, comprising: a plurality of battery modules; a support part provided with a bottom for supporting the plurality of battery modules, sides, a top, and an accommodation space formed by the bottom, the sides, and the top for accommodating the plurality of battery modules; at least one opening provided on either the bottom or sides of the support part to enable the plurality of battery modules to be passed through the at least one opening and be detachably mounted to either the bottom or sides of the support part so as to be supported by either the bottom or sides; and a carbon fibre composite layer of refractory material mounted above the top of the support part to cover the plurality of battery modules accommodated in the support part; and a plurality of battery modules; a support part provided with a bottom for supporting the plurality of battery modules, sides, a top, and an accommodation space formed by the bottom, the sides, and the top for accommodating the plurality of battery modules; at least one opening provided on either the bottom or sides of the support part to enable the plurality of battery modules to be passed through the at least one opening and be detachably mounted to either the bottom or sides of the support part so as to be supported by either the bottom or sides; and a carbon fibre composite layer of refractory material mounted above the top of the support part to cover the plurality of battery modules accommodated in the support part; and wherein the battery pack is configured to be mounted to the lower parts of the two side sills through the bottom of the support part.