Relay unit

A relay unit housed in a battery case, the relay unit comprising:

• a first bus bar;
• a relay that is electrically connected to the first bus bar;
• and
• a device cover that covers the first bus bar and the relay, wherein
• the device cover includes an upper member which has a box shape with an upper end closed and with an opening formed at a lower end, and a lower member which is combined with the upper member in a manner to close the opening of the upper member,
• the lower member is formed from a resin having a higher heat conductive property than the upper member,
• the first bus bar is connected to the lower member in a manner to allow transfer of heat, via a first inner heat conductive sheet placed between the first bus bar and the lower member, the first inner heat conductive sheet is an electrically insulating resin sheet having a lower surface hardness than the lower member,
• the relay unit further comprises an outer heat conductive sheet that is placed at a lower surface of the lower member,
• the first bus bar is connected to the outer heat conductive sheet in a manner to allow the transfer of heat, via the first inner heat conductive sheet and the lower member,
• the relay unit further comprises a second bus bar that is covered by the device cover, wherein
• the relay is electrically connected to each of the first bus bar and the second bus bar, between the first bus bar and the second bus bar,
• a first recess and a second recess which are partitioned by an electrically insulating wall are formed on an upper surface of the lower member,
• the first inner heat conductive sheet is placed in the first recess and the first bus bar is placed in an overlapping manner at an upper side of the first inner heat conductive sheet in the first recess,
• a second inner heat conductive sheet is placed in the second recess and the second bus bar is placed in an overlapping manner at an upper side of the second inner heat conductive sheet in the second recess, and
• the second bus bar is connected to the outer heat conductive sheet in a manner to allow transfer of heat, via the second inner heat conductive sheet and the lower member.