Encasing film for a galvanic element, electrochemical store, electrochemical storage system, flexible film for an encasing of a galvanic element, and method for determining a state variable of an electrochemical store

An electrochemical store for converting chemical energy into electrical energy, comprising:

• a galvanic element;
• and
• an encasing film which encloses the galvanic element,
• wherein the encasing film has at least one force sensor positioned in a middle area of the encasing film, either within the encasing film or on a surface of the encasing film, for detecting an expansion state of the encasing film,
• wherein the encasing film has a further force sensor positioned in an edge area of the encasing film, wherein the edge area is a feedthrough area for at least one electrical contract of the galvanic element such that the at least one electrical contract extends beyond an edge of the encasing film, and
• wherein the expansion state of the encasing film represents a state variable of the galvanic element.

An electrochemical storage system for converting chemical energy into electrical energy, comprising:

• multiple electrochemical stores which are situated in the form of a stack, each electrochemical store including at least one contact for electrical connection of the electrochemical store, a galvanic element and an encasing film which encloses the galvanic element, wherein the encasing film has at least one force sensor positioned either one of within the encasing film or on a surface of the encasing film for detecting an expansion state of the encasing film, and wherein the expansion state of the encasing film represents a state variable of the galvanic element;
• and
• a frame unit comprised of multiple frame elements for fixing a position of each of the electrochemical stores in the stack,
• wherein each electrochemical store is positioned and enclosed between two frame elements so that only the at least one contact for electrical connection for each electrochemical store extends beyond an upper edge of the frame unit.

A method for determining a state variable of an electrochemical store for converting chemical energy into electrical energy, wherein the electrochemical store has a galvanic element enclosed by an encasing film, wherein the encasing film includes at least one force sensor positioned in a middle area of the encasing film and a further force sensor positioned in an edge area of the encasing film, the method comprising:

• detecting a first expansion state in the middle area of the encasing film;
• detecting a second expansion state in the edge area of the encasing film;
• ascertaining a first state variable of the electrochemical store based on the first expansion state;
• and
• ascertaining a second state variable of the electrochemical store based on the second expansion state,
• wherein the first state variable represents a state of charge of the electrochemical store and the second state variable represents a state of aging of the electrochemical store.