TECHNOLOGY FOCUS - INSTRUMENTATION AND TESTING - Preferred Components: In the system: the connection can assume an open or a closed position; the area or its portions of the contact between the storage unit and electrochemical cell compartment and/or the electrolyte compartment is opened upon emergency, so that material from the storage unit is mixed with electrolyte from the electrochemical cell compartment and/or electrolyte compartment; the storage unit further comprises a gas propellant; the connection is normally-closed and upon an emergency or accident, the connection is turned open; the emergency or accident condition is sensed by a sensor within the system or external to the system, where the connection is turned open upon receiving a signal from the sensor; the signal is processed by a processor, which activates or controls activation of the opening of the connection; upon opening of the connection, the reagent is transferred spontaneously into the electrochemical cell compartment and/or to the electrolyte compartment, by using a transferring means; the storage unit comprises the reagent and the gas propellant, so that the gas propellant facilitates ejection of the reagent from the storage unit and into the electrochemical cell compartment and/or to the electrolyte compartment; the pressure of the gas propellant in the storage unit is higher than the gas pressure in the electrochemical cell compartment and/or in the electrolyte compartment; and the reagent is mixed with the electrolyte upon a break or puncture in the electrolyte compartment. The transferring means comprises a pump, a syringe or a rotating screw. The electrolyte compartment comprises an inner layer and an outer layer, where the inner layer comprises the electrolyte, and the outer layer comprises the storage unit for storing the reagent. The system further comprises: a container comprising a blowing agent, where the blowing agent is transferred with the reagent into the electrochemical cell compartment and/or to the electrolyte compartment, so that the blowing agent blows up the reagent or its products, thus forming a porous material; and control sensors comprising a temperature gauge, a pressure gauge, a humidity gauge, a position gauge and/or an accelerometer. The system is activated in response to signals from external controllers including a car controller, an accelerometer and/or an air bag activator. The electrochemical cell further comprises a cathode and an anode.    TECHNOLOGY FOCUS - POLYMERS - Preferred Method: In the method (M1): prior to addition of the reagent to the electrolyte, the electrolyte is kept in a first compartment, and the reagent is kept in a second compartment, where the first compartment and second compartment are placed in contact or are connected by a connection; the area of the contact between the first compartment and the second compartment or their portions is opened upon emergency, so that materials from the two compartments are mixed; the connection between the first compartment and the second compartment can assume an open position or a closed position; and upon opening of the connection, the reagent is transferred to the electrolyte. In the method (M2), the contact between the reagent and electrolyte is achieved by opening the connection, or by opening at least a portion of the contact area between the storage unit and the compartment(s) comprising the electrolyte. Preferred Components: The reagent: comprises a foam, a gel or a porous material, or their precursors; forms a porous solid material, so that the electrolyte solution is contained in the pores of the material; is a polymer or a polymer precursor comprising isocyanate, polyisocyanate, isocyanurate or polyisocyanurate, or their compositions; is absorbent; forms a gel or a foam upon contact with the electrolyte; and comprises superabsorbent polymers. The porous solid material formed from the isocyanate, polyisocyanate, isocyanurate, polyisocyanurate or polyols, or their compositions, polyisocyanate prepolymer or polyisocyanurate prepolymer is polyurethane foam. The second compartment further comprises a gas propellant that facilitates the transfer of the reagent from the second compartment to the first compartment. The superabsorbent polymers comprise cellulose-based polymers, polyacrylate-based polymers and/or polyacrylonitrile-based polymers, or their compositions. The absorbent reagent comprises solution polymerizable polymers or their compositions, where the solution polymerization comprises crosslinking of the polymers/polymer precursors. EXAMPLE - No suitable example given.