Impact modified polystyrene seals for galvanic cells

A seal for a battery having a steel can containing an electrode and electrolyte, the seal configured to electrically isolate the can from the electrode and prevent electrolyte from leaking from the battery, the seal having a relatively thin area designed to rupture in the event that the internal pressure of the battery exceeds a predetermined limit, the seal formed of a styrenic polymer blend comprising from about 70% to about 95% of a styrenic polymer and from about 5% to about 30% of an impact modifier which increases the toughness of the styrenic polymer, based on the total weight of the styrenic polymer and the impact modifier.

A sealed battery including a steel housing containing an electrode and electrolyte, and a seal, the seal configured to electrically isolate the steel housing from the electrode and prevent electrolyte from leaking from the battery, the seal having a relatively thin area designed to rupture in the event that the internal pressure of the battery exceeds a predetermined limit, the seal being formed of a styrenic polymer blend including at least two polymers, at least one of the polymers being a styrenic polymer.