Battery system, method for diagnosing a battery system

A method for diagnosing a battery system (100) that includes

• a battery pack (5) having a positive pole (22), a negative pole (21), at least one battery cell (2), and a pack voltage divider (20), and
• at least one high-voltage coupling network (10) electrically connectable to the battery pack (5), having a positive terminal (12), a negative terminal (11), and a link voltage divider (30), wherein the pack voltage divider (20) comprises:
• a first measuring resistance (RM1) and a first measuring switch (SM1) serially connected to one another between the negative pole (21) and a first reference point (50), and
• a second measuring resistance (RM2) and a second measuring switch (SM2) serially connected to one another between the positive pole (22) and the first reference point (50), wherein the pack voltage divider (30) comprises:
• a third measuring resistance (RM3) connected between the negative terminal (11) and a second reference point (60), and
• a fourth measuring resistance (RM4) connected between the positive terminal (12) and the second reference point (60), and wherein
• the battery system (100) further comprises a first measuring unit (32) for measuring a first measuring voltage (UM1) dropping at the first measuring resistance (RM1), a second measuring unit (34) for measuring a second measuring voltage (UM2) dropping on the second measuring resistance (RM2), a third measuring unit (36) for measuring a third measuring voltage (UM3) dropping at the third measuring resistance (RM3), and a fourth measuring unit (38) for measuring a fourth measuring voltage (UM4) dropping at the fourth measuring resistance (RM4), wherein
• the first measuring unit (32) and the second measuring unit (34) are electrically connected to the first reference point (50), and the third measuring unit (36) and the fourth measuring unit (38) are electrically connected to the second reference point (60),
• wherein the first reference point (50) is connected to a low-voltage coupling network ground (52), and that the second reference point (60) is connected to the negative pole (21) of the battery pack (5),, the method comprising:
• capturing respective measuring voltages (UM1, UM2, UM3, UM4) by means of respective measuring units (32, 34, 36, 38) at different switch positions of the first measuring switch (SM1) and the second measuring switch (SM2);
• and
• calculating insulation resistances (RB1, RB2, RL1, RL2).

An on-board network comprising a battery system (100) that includes:

• a battery pack (5) having a positive pole (22), a negative pole (21), at least one battery cell (2), and a pack voltage divider (20), and
• at least one high-voltage coupling network (10) electrically connectable to the battery pack (5), having a positive terminal (12), a negative terminal (11), and a link voltage divider (30),
• wherein the pack voltage divider (20) comprises:
• a first measuring resistance (RM1) and a first measuring switch (SM1) serially connected to one another between the negative pole (21) and a first reference point (50), and
• a second measuring resistance (RM2) and a second measuring switch (SM2) serially connected to one another between the positive pole (22) and the first reference point (50), wherein
• the pack voltage divider (30) comprises:
• a third measuring resistance (RM3) connected between the negative terminal (11) and a second reference point (60), and
• a fourth measuring resistance (RM4) connected between the positive terminal (12) and the second reference point (60), and wherein
• the battery system (100) further comprises a first measuring unit (32) for measuring a first measuring voltage (UM1) dropping at the first measuring resistance (RM1), a second measuring unit (34) for measuring a second measuring voltage (UM2) dropping on the second measuring resistance (RM2), a third measuring unit (36) for measuring a third measuring voltage (UM3) dropping at the third measuring resistance (RM3), and a fourth measuring unit (38) for measuring a fourth measuring voltage (UM4) dropping at the fourth measuring resistance (RM4), wherein
• the first measuring unit (32) and the second measuring unit (34) are electrically connected to the first reference point (50), and the third measuring unit (36) and the fourth measuring unit (38) are electrically connected to the second reference point (60),
• wherein
• the first reference point (50) is connected to a low-voltage coupling network ground (52), and that
• the second reference point (60) is connected to the negative pole (21) of the battery pack (5).