EP-3940838-B1 - NON-AQUEOUS ELECTROLYTE SECONDARY BATTERY AND METHOD FOR MANUFACTURING NON-AQUEOUS ELECTROLYTE SECONDARY BATTERY

Inventors

• KAIDUKA, ATSUSHI
• SUGII, Noriko

Dates

Publication Date

20260506

Application Date

20200306

Claims (6)

1. A non-aqueous electrolyte secondary battery (10) comprising: a wound-type electrode assembly (14) including a positive electrode (11) and a negative electrode (12) wound together with a separator (13) interposed therebetween; and a battery case (15) housing the electrode assembly (14), wherein the positive electrode (11) has a positive electrode current collector (30) and a positive electrode mixture layer (31) formed on at least one face of the positive electrode current collector (30), characterized in that the separator (13) has a normal region (40) and a plastically deformed region (41) having a puncture strength larger than that of the normal region (40), and the plastically deformed region (41) is formed by stretching a part of the separator (13) in a winding direction.
2. The non-aqueous electrolyte secondary battery (10) according to claim 1, wherein the separator (13) has the plastically deformed region (41) at a position facing at least one of an inner end and an outer end of the positive electrode (11).
3. The non-aqueous electrolyte secondary battery (10) according to claim 1 or 2, wherein the separator (13) has the plastically deformed region (41) at a position facing at least one of an inner end and an outer end of the positive electrode mixture layer (31).
4. The non-aqueous electrolyte secondary battery (10) according to any one of claims 1 to 3, wherein the non-aqueous electrolyte secondary battery (10) further comprises: a conductive positive electrode lead (20) connected to a positive electrode-exposed region (32) in which no positive electrode mixture layer (31) is formed on the face of the positive electrode (11), and a protection member (35) attached to the surface of the positive electrode lead (20), wherein the separator (13) has the plastically deformed region (41) at a position facing at least one end of both lateral ends of the protection member (35) and both lateral ends of the positive electrode lead (20).
5. The non-aqueous electrolyte secondary battery (10) according to any one of claims 1 to 4, wherein the separator (13) includes a polyolefin resin.
6. A method for producing a non-aqueous electrolyte secondary battery (10) comprising: a wound-type electrode assembly (14) including a positive electrode (11) and a negative electrode (12) wound together with a separator (13) interposed therebetween; and a battery case (15) housing the electrode assembly (14), the method including stretching a part of the separator (13) in a winding direction when winding the positive electrode (11) and the negative electrode (12) together with the separator (13) interposed therebetween, to thereby plastically deform the part of the separator (13) and to form a plastically deformed region (41) of the separator (13) having a puncture strength larger than that of a normal region (40) of the separator (14).

Description

TECHNICAL FIELD The present disclosure relates to a non-aqueous electrolyte secondary battery and a method for producing a non-aqueous electrolyte secondary battery. BACKGROUND ART So far, a non-aqueous electrolyte secondary battery including a wound-type electrode assembly and a metal battery case housing the electrode assembly has been widely used, the electrode assembly including a beltlike positive electrode and a beltlike negative electrode wound together with a separator interposed therebetween. Patent Literature 1 discloses a non-aqueous electrolyte secondary battery in which thermal runaway of the battery due to impact from the outside is suppressed in a state of full charge by using a separator having a predetermined tensile strength at break. Then, Patent Literature 2 discloses a manufacturing method of a winding type electrode body and the manufacturing method of a non-aqueous-electrolyte secondary battery with high durability, when used for a non-aqueous-electrolyte secondary battery. Patent Literatures 3 and 4 relate to non-aqueous electrolyte secondary battery. Patent Document 5 discloses an electric storage device, an electric storage system and a manufacturing method thereof. CITATION LIST PATENT LITERATURE PATENT LITERATURE 1: Japanese Unexamined Patent Application Publication No. 2014-139865PATENT LITERATURE 2: Japanese Unexamined Patent Application Publication No. 2002-324570PATENT LITERATURE 3: Japanese Unexamined Patent Application Publication No. 2007-134149PATENT LITERATURE 4: Japanese Unexamined Patent Application Publication No. 2011-138632PATENT LITERATURE 5: European Patent Application Publication No. 2 755 258 A1 TECHNICAL PROBLEM In Patent Literature 1, there is, however, no consideration about an influence on a non-aqueous electrolyte secondary battery in a state of non-full charge when the battery is subjected to impact from the outside. It is an advantage of the present disclosure to provide a non-aqueous electrolyte secondary battery in which internal shorts thereof due to impact from the outside is suppressed both in a state of full charge and that of non-full charge. The invention is defined by the appended claims. SOLUTION TO PROBLEM A non-aqueous electrolyte secondary battery of one aspect of the present disclosure comprises: a wound-type electrode assembly including a positive electrode and a negative electrode wound together with a separator interposed therebetween; and a battery case housing the electrode assembly, characterized in that the positive electrode has a positive electrode current collector and a positive electrode mixture layer formed on at least one face of the positive electrode current collector, and that the separator has a normal region and a plastically deformed region having a puncture strength larger than that of the normal region. A method of another aspect of the present disclosure for producing a non-aqueous electrolyte secondary battery is a method for producing a non-aqueous electrolyte secondary battery comprising: a wound-type electrode assembly including a positive electrode and a negative electrode wound together with a separator interposed therebetween, and a battery case housing the electrode assembly; characterized in that the method includes stretching part of the separator in a winding direction when winding the positive electrode and the negative electrode together with the separator interposed therebetween, to thereby plastically deform the part of the separator. ADVANTAGEOUS EFFECTS OF INVENTION The non-aqueous electrolyte secondary battery according to the present disclosure can withstand impact from the outside both in a state of full charge and that of non-full charge to suppress internal shorts. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a vertical sectional view illustrating a non-aqueous electrolyte secondary battery of an exemplary embodiment.FIG. 2 is a perspective view of the wound-type electrode assembly in the non-aqueous electrolyte secondary battery shown in FIG. 1.FIG. 3 is a longitudinal sectional view of the positive electrode in an exemplary embodiment.FIG. 4 is a plan view illustrating the relation of the positive electrode and the separator facing each other in the electrode assembly in an exemplary embodiment.FIG. 5 is a front view illustrating the configuration of a device for winding the electrode assembly of an exemplary embodiment.FIG. 6 is a side view illustrating the configuration of a stretching section of the winding device shown in FIG. 5.FIG. 7 is a view showing another exemplary embodiment, the view corresponding to FIG. 5. DESCRIPTION OF EMBODIMENTS A non-aqueous electrolyte secondary battery of an exemplary embodiment according to the present disclosure will now be described in detail with reference to drawings. In the descriptions below, specific shapes, materials, values, directions, and others are illustrative for easy appreciation of the present disclosure, and can be appropriately changed accordin