Patent ID: 7414334

Claim:
A circuit for limiting over-voltages in energy storage modules with a plurality of energy storage elements connected in series circuit and wherein the series circut is connected between a first potential and a second potential comprising: a number “n” of energy storage elements connected in series between a first potential source and a second potential source wherein “M” is a maximum number of directly interconnected ones of said energy storage elements in a combination of less than all of said energy storage elements; and a plurality of voltage-limiting elements wherein for M≧2 a respective one of said voltage-limiting elements is connected in parallel with each of the combinations of said energy storage elements, another one of said voltage-limiting elements is connected in parallel with a first one of said energy storage elements connected to the first potential and a further one of said voltage-limiting elements is connected in parallel with an n th one of said energy storage elements connected to the second potential, and wherein for M>2 a respective one of said voltage-limiting elements is connected in parallel with each sub-combination of at least two directly interconnected ones of said energy storage elements of the combination having said first one of said energy storage elements connected to the first potential and the combination having said n th one of said energy storage elements connected to the second potential, and wherein each of said energy storage elements other than said first one of said energy storage elements and said n th one of said energy storage elements is not individually bridged over by any one of said voltage-limiting elements whereby a discharge current of said voltage-limiting elements below a breakdown voltage is reduced.