Method for testing a cell monitoring unit, and testing device
A method is used to test a cell monitoring unit, in which method respective cell voltages are applied to cell voltage connections of the cell monitoring unit. A measurement is then carried out on a cell monitoring unit which is in operation in order to determine whether a respective current is flowing via at least one cell voltage connection, and a fault message is output if this is the case. A testing device is used to test a cell monitoring unit and has at least one current measuring apparatus for measuring currents at cell voltage connections of the cell monitoring unit. The testing device is configured to carry out the method. The method and testing device are applicable in particular to testing a cell monitoring unit of a vehicle, in particular of an electric vehicle.
1. A method for testing a cell monitoring unit, comprising:
applying respective cell voltages to cell voltage connections of the cell monitoring unit; and
carrying out a measurement on a cell monitoring unit which is in operation in order to determine whether a respective current is flowing via at least one cell voltage connection, and, when this is the case, outputting a fault message,
wherein measuring the current comprises interconnecting a current measuring apparatus without interruption in a current line leading to a respective cell voltage connection, further comprising:
connecting the current measuring apparatus initially in parallel with the current line; and then
opening a branch of the current line in parallel with the connections of the current measuring apparatus.
2. The method according to claim 1 , wherein
the current is measured successively at the cell voltage connections.
3. The method according to claim 1 , wherein
a measurement is carried out in order to determine whether a respective current flows at all via at least one cell voltage connection.
4. The method according to claim 1 , wherein
a measurement is carried out in order to determine whether a respective current that is equal to or greater than a predetermined threshold value flows via at least one cell voltage connection.
5. The method according to claim 1 , wherein
the cell voltages applied to the cell voltage connections are additionally measured.
6. A testing device for testing a cell monitoring unit, comprising:
at least one current measuring apparatus for measuring currents at cell voltage connections of the cell monitoring unit;
at least one control device; and
a plurality of switches, wherein
the at least one control device is configured to:
control the plurality of switches to apply respective cell voltages to cell voltage connections of the cell monitoring unit;
control the plurality of switches to interconnect the current measuring apparatus without interruption in a current line leading to a respective cell voltage connection in order to measure the current by:
controlling the plurality of switches to initially connect the current measuring apparatus in parallel with the current line; and then
controlling the plurality of switches to open a branch of the current line in parallel with the connections of the current measuring apparatus; and
carry out a measurement on the cell monitoring unit which is in operation in order to determine whether a respective current is flowing via at least one cell voltage connection, and, when this is the case, output a fault message.
7. The testing device according to claim 6 for testing the cell monitoring unit, wherein
the plurality of switches comprise, for each cell voltage connection to be monitored:
a first switch, a first connection of which is connected to the current line and a second connection of which is connected to a first connection of the current measuring apparatus,
a second switch in the form of a toggle switch, a central connection and first contact connection of which are connected to the current line, the first contact connection of which is connected to the first connection of the first switch and a second contact connection of which is connected to a second connection of the current measuring apparatus, and
a third switch, which is interconnected, in the current line, between the central connection and the first contact connection of the second switch, wherein the at least one control device is configured to:
switch the switches in a rest state outside of a current measuring procedure in such a way that:
the first switch is switched off,
the central connection of the second switch is connected to the first contact connection of the second switch, and
the third switch between the central connection and the first contact connection of the second switch is switched on, and
wherein the at least one control device for a current measuring procedure is configured to:
initially switch on the first switch and to connect the central connection of the second switch to the second contact connection of the second switch to initially connect the current measuring apparatus in parallel with the current line, and then
switch off the third switch between the central connection and the first contact connection of the second switch to open the branch of the current line in parallel with the connections of the current measuring apparatus.
8. The testing device according to claim 7 , wherein the third switch is a toggle switch, which:
is connected by way of the central connection thereof to the first connection of the first switch,
is connected by way of the first contact connection thereof to the central connection of the second switch, and
is connected by way of the second contact connection thereof to a voltage tap.