Secondary battery
AssigneeNEC Corporation
InventorsKenichi Shimura, Kazuhiko Inoue
Life of this patent
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Abstract
Provided is a battery comprising a separator comprising inorganic particles for preventing a short-circuit, wherein the inorganic particles are not removed readily from the separator. This battery is characterized by comprising a separator comprising a base material resin having voids and an inorganic particle having a surface (A) facing the void and a surface (B) in contact with the resin, wherein the length of the surface (A) is 50% or more of the length of the outer periphery of the particle in a cross-sectional SEM photograph of the separator.
Claims6
A battery comprising a separator, the separator comprising
- a porous resin membrane having voids and
- inorganic particles,
- wherein the inorganic particles contained in the separator account for 5 vol % or more of the separator,
- wherein the separator is obtained by bringing an initial composite membrane comprising a resin and the inorganic particles into contact with a removing solution capable of dissolving the inorganic particles to remove 5 vol % to 70 vol % of the inorganic particles to form the voids,
- wherein 50% or more of the inorganic particles contained in the separator have a surface (A) facing one of the voids and a surface (B) in contact with the resin, wherein the length of the surface (A) is 50% or more of the length of the outer periphery of the particle in a cross-sectional SEM photograph of the separator, and
- wherein the voids which are not open on a surface of the separator have a shape in which (the length in the thickness direction)/(the length in an in-plane direction) is 0.3 or more.
A manufacturing method for a battery comprising the steps of:
- fabricating an electrode element by stacking a negative electrode and a positive electrode via a separator, and
- encapsulating the electrode element and an electrolyte solution into an outer package,
- wherein the separator comprises a porous resin membrane having voids and inorganic particles,
- wherein the inorganic particles contained in the separator account for 5 vol % or more of the separator,
- wherein the separator is obtained by bringing an initial composite membrane comprising a resin and the inorganic particles into contact with a removing solution capable of dissolving the inorganic particles to remove 5 vol % to 70 vol % of the inorganic particles to form the voids,
- wherein 50% or more of the inorganic particles contained in the separator have a surface (A) facing one of the voids and a surface (B) in contact with the resin, wherein the length of the surface (A) is 50% or more of the length of the outer periphery of the particle in a cross-sectional SEM photograph of the separator, and
- wherein the voids which are not open on a surface of the separator have a shape in which (the length in the thickness direction)/(the length in an in-plane direction) is 0.3 or more.
Dependencies are inferred from the claim text.