NOVELTY - Lithium-based battery system for vehicle comprises lithium battery cells (130) arranged in series that provide energy to propel vehicle, where each lithium battery cell comprises first (112, 116) and second (120, 124) terminals and lithium battery elements (104, 108), where first terminal of each element connected to terminal of cell; disconnect switches where second terminal of each battery element connected to second terminal of battery cell; and shunt switch connected between terminals of battery cell; and control module which opens and closes shunt switches and disconnect switches.    USE - As battery system to store electrical energy useful in e.g. vehicle such as hybrid motor vehicle, also used in aeronautics, windmills.    ADVANTAGE - The battery system has control module which selectively opens and closes the shunt switches and disconnect switches, hence decreases power lost to heat and prevents damaging short circuit conditions and arcing. The system has high energy and high power electrical battery, thus each element can be very safely shunted from production circuit, without interrupting production of electricity. The control module includes function which allows maintenance of battery by eliminating any source of voltage and this function can be activated after the detection of a shock that could affect the battery. This helps in case of accident of vehicle, in particular crash and also risks of fire may be reduced. The system allows differences in capacity between the elements during phases of use to be compensated without dissipating energy and while maximizing the quantity of energy available in the battery. Moreover, in case of shunting, the current can no longer run between the elements, which contributes to securing the use of high capacity elements, and prevents worsening the risks of thermal runaway.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for electric vehicle power system comprising battery system; and a mechanical shock sensor comprising an accelerometer that generates shock signal when mechanical shock is detected, where control module closes shunt switches when shock signal exceeds threshold.    DESCRIPTION OF DRAWING(S) - The figure shows assembly of electric battery cell.    Elements (104, 108)    Anode terminals (112, 120)    Cathode terminals (116, 124)    Cell (130)