A battery-powered portable tool, comprising: a battery pack (174; 174') containing at least one all-solid-state battery cell (12, 14, 16, 18) within a housing (30, 50); a tool main body, on which and/or inside which the battery pack is mountable and from which the battery pack is demountable; and a battery temperature-measurement circuit disposed only in the battery pack or partially in the tool main body and partially in the battery pack; wherein the battery temperature-measurement circuit comprises: a high-temperature measurement circuit (61, 62, 64; 64-67) that outputs accurate measurement results in a high-temperature range but is less accurate in a low-temperature range, the high-temperature range differing from the low-temperature range; a low-temperature measurement circuit (61, 64; 64-66) that outputs accurate measurement results in the low-temperature range but is less accurate in the high-temperature range; and a switching apparatus (63; Q1, Q2) adapted to select and/or output a signal representative or indicative of the battery temperature based on (i) an output of the low-temperature measurement circuit when an output value of the high-temperature measurement circuit enters a first abnormal range and (ii) an output of the high-temperature measurement circuit when an output value of the low-temperature measurement circuit enters a second abnormal range. a battery pack (174; 174') containing at least one all-solid-state battery cell (12, 14, 16, 18) within a housing (30, 50); a tool main body, on which and/or inside which the battery pack is mountable and from which the battery pack is demountable; and a battery temperature-measurement circuit disposed only in the battery pack or partially in the tool main body and partially in the battery pack; wherein the battery temperature-measurement circuit comprises: a high-temperature measurement circuit (61, 62, 64; 64-67) that outputs accurate measurement results in a high-temperature range but is less accurate in a low-temperature range, the high-temperature range differing from the low-temperature range; a low-temperature measurement circuit (61, 64; 64-66) that outputs accurate measurement results in the low-temperature range but is less accurate in the high-temperature range; and a switching apparatus (63; Q1, Q2) adapted to select and/or output a signal representative or indicative of the battery temperature based on (i) an output of the low-temperature measurement circuit when an output value of the high-temperature measurement circuit enters a first abnormal range and (ii) an output of the high-temperature measurement circuit when an output value of the low-temperature measurement circuit enters a second abnormal range. a high-temperature measurement circuit (61, 62, 64; 64-67) that outputs accurate measurement results in a high-temperature range but is less accurate in a low-temperature range, the high-temperature range differing from the low-temperature range; a low-temperature measurement circuit (61, 64; 64-66) that outputs accurate measurement results in the low-temperature range but is less accurate in the high-temperature range; and a switching apparatus (63; Q1, Q2) adapted to select and/or output a signal representative or indicative of the battery temperature based on (i) an output of the low-temperature measurement circuit when an output value of the high-temperature measurement circuit enters a first abnormal range and (ii) an output of the high-temperature measurement circuit when an output value of the low-temperature measurement circuit enters a second abnormal range.