Abstract: The state of charge of a cell that has flexible packaging and that expands and contracts with variations in state of charge is determined by measuring changes in thickness of the cell. The invention is particularly applicable to cells having a flat geometry. A battery having a state-of-charge indicator includes at least one battery cell free to expand and contract with variations in state of charge of the battery cell and a device for measuring expansion or contraction of the battery cell, a resulting measurement indicating the state of charge of the battery cell. By measuring expansion or contraction of the battery the state of charge of a battery may be readily detected. The measurement may be directly displayed so as to be visually observable, or a signal containing measurement information may be sent to a remote location to be displayed or used for control purposes.

Abstract: There is provided a method for measuring and evaluating hardness or toughness of relatively delicate materials such as polymers, semi-solids, colloids or gels to determine the firmness thereof by inserting a stylus a specific depth into the material and then determining how the material itself reacts by measuring a resultant opposing force caused by insertion of the stylus. The device used in the method of the invention comprises a stylus (plunger) to vertically impinge on the sample when the stylus is displaced vertically downward. An actuating means controls downward movement of the stylus. The actuating means comprises a movable shaft and a stationary sleeve. The shaft has one end which is threaded and a second end which is constructed and arranged to carry the stylus. The stationary sleeve has internal threads for cooperative engagement with the external threads of the shaft, whereby adjustment by the threads causes vertical movement of the stylus.