A battery pack for a vehicle, the battery pack comprising: a plurality of batteries including a first battery and a second battery; a first input/output port including a first input/output positive port (T1a) electrically connected to a positive terminal of the first battery and a first input/output negative port (T1b); a second input/output port including a second input/output positive port (T2a) and a second input/output negative port; a first 3-way switch (Sa) comprising a common terminal (Ca 1), a first contact terminal (Ca 2) and a second contact terminal (Ca 3), a second 3-way switch (Sb) comprising a common terminal (Cb 1), a first contact terminal (Cb 2) and a second contact terminal (Cb 3), a third 3-way switch (Sc) comprising a common terminal (Cb 1), a first contact terminal (Cb 2) and a second contact terminal (Cb 3), wherein the common terminal (Ca 1) of the first 3-way switch is electrically connected to a positive terminal (112 a) of the second battery, the first contact terminal (Ca 2) of the first 3-way switch (Sa) is electrically connected to the first contact terminal (Cb 2) of the second 3-way switch (Sb) and the second contact terminal (Ca 3) of the first 3-way switch (Sa) is electrically connected to the second input/output positive port (T2a), and wherein the common terminal (Cb 1) of the second 3-way switch (Sb) is electrically connected to a negative terminal (111 b) of the first battery, and the second contact terminal (Cb 3) of the second 3-way switch (Sb) is electrically connected to the common terminal (Cc 1) of the third 3-way switch (Sc) and to a negative terminal (112 b) of the second battery, and wherein the first contact terminal (Cc 2) of the third 3-way switch (Sc) is electrically connected to the first input/output negative port (T1b) and the second contact terminal (Cc 3) of the third 3-way switch (Sc) is electrically connected to the second input/output negative port (T2b). a plurality of batteries including a first battery and a second battery; a first input/output port including a first input/output positive port (T1a) electrically connected to a positive terminal of the first battery and a first input/output negative port (T1b); a second input/output port including a second input/output positive port (T2a) and a second input/output negative port; a first 3-way switch (Sa) comprising a common terminal (Ca 1), a first contact terminal (Ca 2) and a second contact terminal (Ca 3), a second 3-way switch (Sb) comprising a common terminal (Cb 1), a first contact terminal (Cb 2) and a second contact terminal (Cb 3), a third 3-way switch (Sc) comprising a common terminal (Cb 1), a first contact terminal (Cb 2) and a second contact terminal (Cb 3), wherein the common terminal (Ca 1) of the first 3-way switch is electrically connected to a positive terminal (112 a) of the second battery, the first contact terminal (Ca 2) of the first 3-way switch (Sa) is electrically connected to the first contact terminal (Cb 2) of the second 3-way switch (Sb) and the second contact terminal (Ca 3) of the first 3-way switch (Sa) is electrically connected to the second input/output positive port (T2a), and wherein the common terminal (Cb 1) of the second 3-way switch (Sb) is electrically connected to a negative terminal (111 b) of the first battery, and the second contact terminal (Cb 3) of the second 3-way switch (Sb) is electrically connected to the common terminal (Cc 1) of the third 3-way switch (Sc) and to a negative terminal (112 b) of the second battery, and wherein the first contact terminal (Cc 2) of the third 3-way switch (Sc) is electrically connected to the first input/output negative port (T1b) and the second contact terminal (Cc 3) of the third 3-way switch (Sc) is electrically connected to the second input/output negative port (T2b).