An electrode system comprising: a plurality of first electrode plates (3) and a plurality of second electrode plates (5′) arranged alternatingly to form an electrode stack, each first electrode plate having a first electrode plate first busbar opening and a first electrode plate second busbar opening extending through the first electrode plate, the first electrode plate second busbar opening being larger than the first electrode plate first busbar opening, each second electrode plate (5′) having a second electrode plate first busbar opening (27a′) extending through the second electrode plate (5′), the second electrode plate first busbar opening (27a′) being dimensioned larger than each of the first electrode plate first busbar openings and aligned with the first electrode plate first busbar openings, and a second electrode plate second busbar opening (27b′) extending through the second electrode plate (5′), the second electrode plate second busbar opening (27b′) being dimensioned smaller than each of the first electrode plate second busbar openings and aligned with the first electrode plate second busbar openings, a first busbar extending through the first electrode plate first busbar openings and the second electrode plate first busbar openings (27b′), the first busbar being configured to be in mechanical contact with an inner first busbar surface of the first electrode plate first busbar openings only, and a second busbar extending through the first electrode plate second busbar openings and the second electrode plate second busbar openings (27b′), the second busbar being configured to be in mechanical contact with an inner second busbar surface of the second electrode plate second busbar openings (27b′) only.