Bypass element for safeguarding battery cells

Claim 1

Bypass element for a battery having a plurality of series-connected groups of electrochemical battery cells, each group having a plurality of parallel-connected branches of battery cells based on alkali metal, chalcogen and an alkali ion-conducting solid electrolyte, the bypass element being connected in parallel with each respective battery cell or with each respective group of battery cells for safeguarding the battery cells by bypassing the cells when a predeterminable maximum charging capacity of the battery cells is reached, said bypass element comprising a series-connection of first and second semiconductor components, said components being capable of assuming a high-impedance and a low impedance state with different current/voltage characteristics in response to current or voltage applied to the cell, said first semiconductor component having a lower leakage current in the high-impedance state than said second semiconductor component, said second semiconductor component changing from the high-impedance to the low-impedance state at a higher voltage or higher current than said first semiconductor component, and said first semiconductor component changing from the high-impedance to the low-impedance state exactly when a maximum charging voltage of the battery cell or of the group of battery cells is reached, including a housing formed of an electrically conductive material, a fusible component disposed in said housing along with said semiconductor components, and positive and negative electrical connecting elements connected to said housing, each of said semiconductor components having first and second connecting terminals, the housing including an electrically conducting contact element in the form of a spring electrically conductively connecting said first connecting terminal of said first semiconductor component through said housing to said negative connecting elements of said housing, the housing further including a rod-shaped internal conductor directly electrically conductively connecting said second connecting terminal of said second semiconductor component to said positive connecting element of said housing, and said second connecting terminal of said first semiconductor component being electrically conductively connected to said first connecting terminal of said second semiconductor component.