US-12626855-B2 - Coil component

US12626855B2US 12626855 B2US12626855 B2US 12626855B2US-12626855-B2

Abstract

In the coil component, the external terminal and the metal magnetic powder-containing resin constituting the element body are not in direct contact with each other, and thus high ESD resistance is obtained. That is, even when a high transient voltage is applied between the pair of external terminals, insulation breakdown is less likely to occur, and an improvement in breakdown voltage with respect to the transient voltage can be realized.

Inventors

Shota Otsuka
Takashi Kudo
Kyohei Tonoyama
Taiji MATSUI
Ken Satoh
Miyuki Asai

Assignees

TDK CORPORATION

Dates

Publication Date: 20260512
Application Date: 20221012
Priority Date: 20211014

Claims (4)

1 . A coil component comprising: an element body made of a magnetic material including metal powder and resin, the element body having an upper surface and a lower surface parallel to each other, and a pair of end surfaces orthogonal to the upper surface and the lower surface; an insulating substrate disposed in the element body, the insulating substrate extending parallel to the upper surface and the lower surface, and is exposed at each of the pair of end surfaces; and a first coil body disposed in the element body and formed on the upper surface of the insulating substrate, the first coil body including a first planar coil having a first connection end portion, a first lead-out end portion, and a first turn portion connecting the first connection end portion and the first lead-out end portion, and a first insulator covering the first planar coil in the same layer as a layer in which the first planar coil is formed; a second coil body disposed in the element body and formed on the lower surface of the insulating substrate, the second coil body including a second planar coil having a second connection end portion connected to the first connection end portion of the first planar coil via the insulating substrate, a second lead-out end portion, and a second turn portion connecting the second connection end portion and the second lead-out end portion, and a second insulator covering the second planar coil in the same layer as the layer in which the second planar coil is formed; and a pair of external terminals respectively provided on the end surfaces of the element body and respectively connected to the first lead-out end portion of the first planar coil and the second lead-out end portion of the second planar coil, wherein at least one of the first insulator and the second insulator is formed over the entire width of the end surface on the insulating substrate and is exposed, and an insulating layer interposed between the external terminal and the element body is formed in a remaining region of an exposed region in the end surface, and wherein the first coil body and the second coil body are flush with the end face of the element body, and do not protrude from the element body, and the first insulator and the second insulator are thick-film resists having openings at a top or a bottom side thereof.
2 . The coil component according to claim 1 , wherein both the first insulator and the second insulator are formed over the entire width of the end surface on the insulating substrate and are exposed, and the insulating layer is formed in the remaining region of the pair of end surfaces.
3 . The coil component according to claim 1 , wherein the insulating layer covers at least a portion of the first insulator or the second insulator exposed at the end surface.
4 . The coil component according to claim 1 , wherein the first coil body includes a first insulating layer covering the first planar coil from the upper surface side and is exposed at the end surface, and the second coil body includes a second insulating layer covering the second planar coil from the lower surface side and is exposed at the end surface.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2021-168518, filed on 14 Oct. 2021, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD The present disclosure relates to a coil component. BACKGROUND Well known in the art is a coil component in which a coil is provided in an element body made of magnetic material containing metal powder and resin. Patent Document 1 discloses a coil component including a coil having both end portions extracted to end surfaces of the element body, and a pair of external terminals respectively provided on the end surfaces of the element body and electrically connected to the end portions of the coil. PATENT DOCUMENTS Patent Document 1: U.S. Patent Application Publication No. 2016/0086714Patent Document 2: Japanese Patent Application Publication No. 2021-093468 SUMMARY The above-described coil component is required to have Electro-Static Discharge (ESD) resistance that does not cause insulation breakdown even when large static electricity is instantaneously applied. In particular, the ESD resistance against an extremely high transient voltage (for example, 25 kV) is required for an in-vehicle coil component. The inventors have repeatedly studied the ESD resistance of the coil component, and have newly found a technique capable of improving the withstand voltage against the transient voltage. According to the present disclosure, a withstand voltage against a transient voltage of a coil is improved. According to one aspect of the present disclosure, there is provided A coil component including an element body made of a magnetic material including metal powder and resin, the element body having an upper surface and a lower surface parallel to each other, and a pair of end surfaces orthogonal to the upper surface and the lower surface, an insulating substrate disposed in the element body, the insulating substrate extending parallel to the upper surface and the lower surface, and is exposed at each of the pair of end surfaces, and a first coil body disposed in the element body and formed on the upper surface of the insulating substrate, the first coil body including a first planar coil having a first connection end portion, a first lead-out end portion, and a first turn portion connecting the first connection end portion and the first lead-out end portion, and a first insulator covering the first planar coil in the same layer as a layer in which the first planar coil is formed, a second coil body disposed in the element body and formed on the lower surface of the insulating substrate, the second coil body including a second planar coil having a second connection end portion connected to the first connection end portion of the first planar coil via the insulating substrate, a second lead-out end portion, and a second turn portion connecting the second connection end portion and the second lead-out end portion, and a second insulator that covering the second planar coil in the same layer as the layer in which the second planar coil is formed, and a pair of external terminals respectively provided on the end surfaces of the element body and respectively connected to the first lead-out end portion of the first planar coil and the second lead-out end portion of the second planar coil, wherein at least one of the first insulator and the second insulator is formed over the entire width of the end surface on the insulating substrate and is exposed, and an insulating layer interposed between the external terminal and the element body is formed in a remaining region of an exposed region in the end surface. In the coil component, since the end surface of the element body is divided into the region where the insulating layer is formed or the region where the first insulator or the second insulator is exposed and the element body is not exposed, the external terminal provided on the end surface and the element body are not in direct contact with each other. Therefore, even when a high transient voltage is applied between the pair of external terminals, insulation breakdown is unlikely to occur, and the withstand voltage of the coil component against the transient voltage is improved. In the first insulator and the second insulator, voids are less likely to occur than in the insulating layer, and insulation breakdown is less likely to occur than in the insulating layer. In the above-described coil component, by exposing the entire width of the end surface of the element body, the reliability of the withstand voltage with respect to the transient voltage is improved compared to a case where the insulating layer is formed on the entire area of the end surface. In a coil component according to another aspect, both the first insulator and the second insulator are formed over the entire width of the end surface on the insulating substrate and are exposed, and the insulating laye