Stack Mode Cell Connections; Membrane Cell Connections - Gamry Instruments Reference 3000 Operator's Manual

Stack Mode Cell Connections

Batteries, fuel cells, and super-capacitors are often connected with several individual cells connected in series
to allow higher-voltage operation. This type of connection is a stack connection. Special experiment scripts
allow the Reference 3000 to control and measure stack voltages as large as its compliance voltage (15 V or
30 V). These scripts refer to Stack Mode cell connections. The cell connections in Stack Mode differ from
those in Potentiostatic and Galvanostatic modes.
Voltages in Stack Mode are measured as the voltage difference between the Counter Sense input and the
Working Sense Input. A special high-voltage electrometer allows the orange lead to operate at high voltage and
still draw minimal current from the system under test.
Connections in Stack mode are very similar to ZRA mode. The cell cable connections for Stack mode are
shown in Table 6-3.
Cell Cable Connections for ZRA Mode (Voltages greater than 12 V)
Color Type
Blue Banana plug
Green Banana plug
White Pin jack
Red Banana plug
Orange Banana plug
Black Pin jack
The Counter Sense and the Counter leads are connected to one end of a stack. The Working and the Working
Sense leads are connected to opposite ends of a Stack.
The white pin jack on the cell cable can be connected to a low-voltage point in the stack. Some Gamry scripts
allow the voltage difference between the white and blue leads to be read, even though the Reference 3000 is
in Stack Mode. The white pin can be connected to a reference electrode—provided the difference between
the working and the reference does not exceed 12 V.
The orange lead can be connected to second end of stack or a reference electrode.
If the instrument is connected in stack mode and the reference input is not used, it should be connected to the
floating ground wire. A pin-plug shorting bar is provided for this purpose.
If you don't have a reference electrode in your cell, we recommend that you connect the white reference lead
to the working electrode. In theory, the measured potential is exactly zero when this is done. In practice, A/D
noise and offset create a small potential signal with a value very close to zero.

Membrane Cell Connections

The Reference 3000 can be used with membrane cells. In this type of cell, a membrane separates two
electrolyte solutions. Two reference electrodes are used—one in each electrolyte. Each electrolyte also contains
a counter electrode. The Reference 3000 controls the potential across the membrane. Table 6-4 shows the cell
connections used with a membrane-type cell.
Cell Connections – Stack Mode Cell Connections
Table 6-3
Name
Working Sense
Working Electrode
Reference
Counter Electrode
Counter Sense
Floating Ground
46
Normal Connection
Connect to first end of a stack
Connect to first end of a stack
Can be connected to a reference electrode
Connect to the second end of a stack
Connect to the second end of a stack
Leave open or connect to a Faraday shield