Patent Description:
Fuses, also called current fuses, are defined by IEC127 standard as "fuse-link". A fuse is used for overload protection. Fuses can be blown to cut off current to secure safe operation of a circuit when the current of the fuse rises above a certain threshold value in an abnormal situation.

<CIT> discloses an electrical fuse having an element which includes a strip of conductive metal connectable to the fuse terminals, the strip of conductive material having a plurality of holes through its thickness dimension spaced along the center line of its width, successive ones of the holes through the strip each having a slot joining that hole with an opposite one of the edges from the edge joined by the adjacent hole and its associated slot.

<CIT> discloses a fuse including a fuse element and a fuse body. A portion of the fuse element is housed in the fuse body. The fuse element includes a first terminal and a second terminal disposed outside of the fuse body.

<CIT> discloses a bimetallic fuse element comprising pairs of high melting point elements of tinned copper connected together by a low melting-point element of a lead-tin alloy in which the high melting-point elements have narrow regions of reduced cross-section provided either by a series of holes or shallow grooves.

<CIT> discloses an electrical fuse, in particular for a motor vehicle, having two terminal regions and a melting range of a conductor strip with an integrated holder and a fusible element mounted therein connecting them, which has a low melting material which overload current melts at one and into the conductor strip diffuses, wherein the fusible element is introduced through a mechanical fastening operation.

<CIT> discloses a blade type plug-in fuse for high nominal currents. It is of the type comprising a case in which is partially housed a conductive unit provided with two flat connection terminal blades whose free ends are situated outside the case, said connection terminal blades being connected inside the case by a flat fuse link part on at least one side and substantially in the center of which is deposited a drop of metal of predetermined area of contact, and it is characterized in that the fuse link part comprises a central gauging zone of width smaller than the width of the adjacent lateral zones connecting with the connection terminal blades, the area of contact of said drop being at least greater than half the area of the gauging zone.

However, present fuses conduct heat fast, such that the heat cannot be concentrated to the fusing position, which causes that the fuse is not blown in time or is blown at an abnormal position.

Therefore, there is a need for a new safety device to solve the above problem in the prior art.

The present invention provides a safety device, which can reduce a diffusion speed of heat and causes a connecting part thereof to be blown in time.

To achieve the above object, a first aspect of the present invention provides the following technical solution: a safety device for preventing overcurrent comprises a first heat dissipation portion made of an electrically conductive material, a second heat dissipation portion made of an electrically conductive material, a connecting part made of an electrically conductive material arranged between the first heat dissipation portion and the second heat dissipation portion, and provided with at least one heat locking hole. The connecting part has a first heat locking portion, a fusing portion, and a second heat locking portion, wherein the at least one heat locking hole is located in the first heat locking portion and/or the second heat locking portion. Each of the first heat dissipation portion and the second heat dissipation portion is provided with a mounting pin and at least an auxiliary pin, both mounting pins and the auxiliary pins being suitable for mounting the safety device on a printed circuit board.

In one embodiment of the present disclosure, two first auxiliary heat locking openings are provided on each side of a jointing portion between the first heat dissipation portion and the connecting part, and two second auxiliary heat locking openings are provided on each side of a jointing portion between the second heat dissipation portion and the connecting part.

In one embodiment of the present disclosure, the number of the heat locking holes is two, the two heat locking holes are a first heat locking hole located in the first heat locking portion and a second heat locking hole located in the second heat locking portion.

In one embodiment of the present disclosure, the first heat locking portion, the second heat locking portion and the fusing portion all have a symmetrical structure, the first heat locking portion is provided with a first edge and a second edge which are symmetrical in position and shape, the second heat locking portion is provided with a third edge and a fourth edge which are symmetrical in position and shape, the fusing portion is provided with a fifth edge and a sixth edge which are symmetrical in position and shape, the first edge, the fifth edge and the third edge are sequentially connected, and the second edge, the sixth edge and the fourth edge are sequentially connected.

In one embodiment of the present disclosure, the first heat locking hole and the second heat locking hole are symmetrically in shape, and the first heat locking hole has the same symmetry axis as the first heat locking portion, and the second heat locking hole has the same symmetry axis as the second heat locking portion.

In one embodiment of the present disclosure, a maximum distance from the fifth edge to the sixth edge is less than or equal to a minimum distance from the first edge to the second edge, and also less than or equal to a minimum distance from the third edge to the fourth edge.

In one embodiment of the present disclosure, a sum of two minimum distances from any two symmetrical positions on the first edge and the second edge to the first heat locking hole is greater than a minimum distance from the fifth edge to the sixth edge.

In one embodiment of the present disclosure, a sum of two minimum distances from any two symmetrical positions on the third edge and the fourth edge to the second heat locking hole is greater than a minimum distance from the fifth edge to the sixth side.

In one embodiment of the present disclosure, the heat locking hole is filled with a fusible material.

In one embodiment of the present disclosure, the fusing portion is provided with a fusing hole having a symmetrical shape.

In one embodiment of the present disclosure, the fusing hole is filled with an auxiliary fuse material.

In one embodiment of the present disclosure, the fusing portion is integrally formed with the first heat locking portion and the second heat locking portion.

In one embodiment of the present disclosure, the fusing portion has a welded connection with the first heat locking portion and the second heat locking portion, the first heat locking portion and the second heat locking portion are made of a high thermally conductive material, and the fusing portion is made of a fusing material.

To achieve the above object, a second aspect of the present invention provides a battery pack, comprising a housing, a circuit board disposed in the housing, a safety device according to the first aspect mounted to the circuit for preventing overcurrent.

Exemplary embodiments will be described in detail herein, and the embodiments are illustrated in the accompanying drawings. When the following description refers to the drawings, unless otherwise indicated, the same numbers in different drawings indicate the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. On the contrary, they are only examples of devices consistent with some aspects of the invention as detailed in the appended claims.

In view of the problem in the prior art, an embodiment of the present disclosure provides a safety device. Referring to <FIG>, the safety device <NUM> comprises a first dissipation portion <NUM>, a second dissipation portion <NUM>, and a connecting part <NUM> disposed between the first dissipation portion <NUM> and the second dissipation portion <NUM>. The connecting part <NUM> is provided with a first heat locking hole <NUM> and a second heat locking hole <NUM>. The first heat dissipation portion <NUM> is provided with a first mounting pin <NUM> on a left side thereof (i.e., the side directed away from the connecting part <NUM>), and two first auxiliary pins <NUM> provided on a front side and a rear side of the first heat dissipation portion <NUM>, respectively. The second heat dissipation portion <NUM> is provided with a second mounting pin <NUM> on a right side thereof (i.e., the side directed away from the connecting part <NUM>) and two second auxiliary pins <NUM> provided on a front side and a rear side of the second heat dissipation portion <NUM>, respectively.

Referring to <FIG>, the first dissipation portion <NUM> has two first auxiliary heat locking openings <NUM> disposed at both sides of a jointing part of the first heat dissipation portion <NUM> and the connecting portion <NUM>. The second dissipation portion12 has two second auxiliary heat locking openings <NUM> disposed at both sides of a jointing part of the second heat dissipation portion <NUM> and the connecting portion <NUM>. The two first auxiliary heat locking opening <NUM> reduces a connecting surface of the first dissipation portion <NUM> and the connecting part <NUM>, and the second auxiliary heat locking opening <NUM> reduces a connecting surface of the second dissipation portion <NUM>, i.e. the connecting part <NUM> can slow down the heat transfer speed and avoid a rapid temperature diffusion.

<FIG> is a top view of the safety device shown in <FIG>. Referring to <FIG>, the connecting part <NUM> has a first heat locking portion <NUM>, a fusing portion <NUM> and a second heat locking portion <NUM> in sequence from left to right. The connecting part <NUM> has a symmetrical structure, the first heat locking hole <NUM> is located in the first heat locking portion <NUM>, the second heat locking hole <NUM> is located in the second heat locking portion <NUM> and the fusing portion <NUM> is integrally formed with the first heat locking portion <NUM> and the second heat locking portion <NUM>.

In some embodiments of the present disclosure, the first heat locking portion <NUM>, the integrally formed fusing portion <NUM>, and the second heat locking portion <NUM> are made of a metallic material, such as copper alloy, nickel, aluminum, etc..

In some embodiments of the present disclosure, the first heat locking portion <NUM>, the integrally formed fusing portion <NUM>, and the second heat locking portion <NUM> are made of brass.

In some embodiments of the present disclosure, referring to <FIG>, the first heat locking portion <NUM>, the fusing portion <NUM> and the second heat locking portion <NUM> all have a symmetrical structure. The first heat locking portion <NUM> is provided with a first edge <NUM> and a second edge <NUM>, which are symmetrical in position and shape. The second heat locking portion <NUM> is provided with a third edge <NUM> and a fourth edge <NUM>, which are symmetrical in position and shape. The fusing portion <NUM> is provided with a fifth edge <NUM> and a sixth edge <NUM>, which are symmetrical in position and shape. The first edge <NUM> is connected with one end of the fifth edge <NUM> and the other end of the fifth edge <NUM> is connected with the third edge <NUM>. The second edge <NUM> is connected with one end of the sixth edge <NUM> and the other end of the sixth edge <NUM> is connected with the fourth edge <NUM>. The first heat locking hole <NUM> is located on a symmetry axis of the first heat locking portion <NUM>, and the second heat locking hole <NUM> is located on a symmetry axis of the second heat locking portion <NUM>.

In some embodiments of the present disclosure, the first heat locking portion <NUM> has the same axis of symmetry as the second heat locking portion <NUM>. In some preferred embodiments of the present disclosure, a maximum distance from the fifth edge <NUM> to the sixth edge <NUM> is less than or equal to a minimum distance from the first edge <NUM> to the second edge <NUM>, and is also less than or equal to a minimum distance from the third edge <NUM> to the fourth edge <NUM>. A sum of two minimum distances from any two symmetrical positions on the first edge <NUM> and the second edge <NUM> to the first heat locking hole <NUM> respectively, is greater than a minimum distance from the fifth edge <NUM> to the sixth edge <NUM>. A sum of two minimum distances from any two symmetrical positions on the third edge <NUM> and the fourth edge <NUM> to the second heat locking hole <NUM> respectively, is also greater than the minimum distance from the fifth edge <NUM> to the sixth edge <NUM>. The maximum distance between two edges is a maximum value of the distances between all the symmetrical points on the two edges; the minimum distance between two edges is the minimum value of the distances between all the symmetrical points on the two edges.

In some embodiments of the present disclosure, the first heat locking hole <NUM> and the second heat locking hole <NUM> are both symmetrical in shape, and the first heat locking hole <NUM> has the same symmetry axis as the first heat locking portion <NUM>, and the second heat locking hole <NUM> has the same symmetry axis as the second heat locking portion <NUM>. Therefore, a distance from a position of the first edge <NUM> to the center of the first heat locking hole <NUM> is equal to a distance from a corresponding symmetrical position of the second edge <NUM> to the center of the first heat locking hole <NUM>, and a distance from a position of the third edge <NUM> to the center of the second heat locking hole <NUM> is equal to a distance from a corresponding symmetrical position of the fourth edge <NUM> to the center of the second heat locking hole <NUM>.

In some embodiments of the present disclosure, the first heat locking hole <NUM> and the second heat locking hole <NUM> have the same shape and size and are symmetrically in position.

In some embodiments of the present disclosure, referring to <FIG>, the first heat locking hole <NUM> and the second heat locking hole <NUM> are circular in shape.

In some embodiments of the present disclosure, the first heat locking hole <NUM> and the second heat locking hole <NUM> are filled with a fusible material, which can melt quickly after absorbing heat, in order to decrease the temperature of the first heat locking portion <NUM> and the second heat locking portion <NUM>, which extends the fusing time of the fusing portion <NUM> and avoid fusing when the fusing requirement is not met.

In some embodiments of the present disclosure, the fusible material is tin whose melting point is <NUM>.

<FIG> is a perspective view of another safety device according to some embodiments of the present disclosure. The safety device shown in <FIG> has the same structure as the safety device shown in <FIG>, with the difference that the fusing portion <NUM> is provided with a fusing hole <NUM>.

In some embodiments of the invention, the first heat locking hole <NUM> communicates with the second heat locking hole <NUM> by the fusing hole <NUM>.

In some embodiments of the present disclosure, the fusing hole <NUM> of the fusing portion <NUM> is filled with a fusible material. When a high heavy current passes through the fusing portion <NUM>, the fusible material can preferentially melt into liquid, according to a diffusion principle- A very strong diffusion motion will occur between the fusible material and the fusing portion <NUM> and since a high temperature of the fusing portion <NUM> is more conducive to the diffusion motion tension will occur between the fusible material in liquid form and the fusing portion <NUM> in solid form during the diffusion process. The tension aggravates the diffusion motion and easily blows the fusing portion <NUM>.

In some embodiments of the present disclosure, the fusible material is tin.

In some embodiments of the present disclosure, the fusing hole <NUM> has a symmetrical shape, such that a distance from the fifth edge <NUM> to the center of the fusing hole <NUM> is equal to the distance from the symmetrical position of the sixth edge <NUM> to the center of the fusing hole <NUM>.

In some embodiments of the present disclosure, the shape of the fusing hole is oval, square, diamond, circle, etc., and the shape of the first heat locking hole and the second heat locking hole may also have corresponding shapes , but are not limited thereto.

<FIG> is a perspective view of another safety device according to some embodiments of the present disclosure. The safety device shown in <FIG> has the same structure as the safety device shown in <FIG>, with the difference that the fusing portion is a welded fusing portion <NUM>. The welded fusing portion <NUM> is connected with the first heat locking portion <NUM> and the second heat locking portion <NUM> in a welded manner. The first heat locking portion <NUM> and the second heat locking portion <NUM> are made of a highly heat conductive material, and the welded fusing portion <NUM> is made of a fusing material. In this case the first heat locking portion <NUM> and the second heat locking portion <NUM> do not need to be blown, and their fusing characteristics do not need to be considered, so that the first heat locking portions <NUM> and the second heat locking portion <NUM> can made of any highly thermal conductive material known in this field.

In some embodiments of the present disclosure, referring to <FIG>, the welded fusing portion <NUM> has some bumps <NUM> after being welded by resistance welding.

In some embodiments of the present disclosure, the welded fusing portion <NUM> has no bumps after being welded by laser welding.

In some embodiments of the present disclosure, the fusing material of the welded fusing portion <NUM> is aluminum, whose melting point is <NUM> , which can meet the fusing requirements.

<FIG> is a top view of another safety device according to some embodiments of the present disclosure. Referring to <FIG> and <FIG>, the safety device <NUM> differs from the safety device <NUM> in that the first heat locking hole <NUM> and the second heat locking hole <NUM> are semicircular.

<FIG> is a top view of another safety device according to some embodiments of the present disclosure. Referring to <FIG> and <FIG>, the safety device <NUM> differs from the safety device <NUM> in that the first heat locking hole <NUM> and the second heat locking hole <NUM> are rectangular.

<FIG> is a top view of another safety device according to some embodiments of the present disclosure. Referring to <FIG> and <FIG>, the safety device <NUM> differs from the safety device <NUM> in that the first heat locking hole <NUM> and the second heat locking hole <NUM> have a circular arc form.

<FIG> is a top view of another safety device according to some embodiments of the invention. Referring to <FIG> and <FIG>, the safety device <NUM> differs from the safety device <NUM> in that the safety device <NUM> does not have the first auxiliary heat locking slot <NUM> and the second auxiliary heat locking slot <NUM>.

<FIG> is a perspective view of another safety device according to some embodiments of the present disclosure. Referring to <FIG> and <FIG>, the safety device <NUM> differs from the safety device <NUM> in that the first heat locking hole <NUM> and the second heat locking hole <NUM> are different in size.

<FIG> is a perspective view of another safety device according to some embodiments of the present disclosure. Referring to <FIG> and <FIG>, the safety device <NUM> differs from the safety device <NUM> in that the first heat locking hole <NUM> and the second heat locking hole <NUM> have e non-symmetrical positions.

<FIG> is a perspective view of another safety device according to some embodiments of the present disclosure. Referring to <FIG> and <FIG>, the safety device <NUM> differs from the safety device <NUM> in that the first heat locking hole <NUM> and the second heat locking hole <NUM> have asymmetric positions and are different in size.

<FIG> is a perspective view of another safety device according to some embodiments of the present disclosure. Referring to <FIG> and <FIG>, the safety device <NUM> differs from the safety device <NUM> in that a first connection section <NUM> comprises a first front edge <NUM> and a first rear edge <NUM>, both of which are parallel to the X-axis.

<FIG> is a top view of another safety device according to some embodiments of the invention. Referring to <FIG>, <FIG> and <FIG>, the safety device <NUM> differs from the safety device <NUM> in that a second connecting part <NUM> comprises a second front edge <NUM> and a second rear edge <NUM> parallel to the second rear edge <NUM>, wherein the second front edge <NUM> is non-parallel to X-axis, and the first auxiliary heat locking portion and the second auxiliary heat locking portion are removed.

<FIG> is a top view of another safety device according to some embodiments of the present disclosure. Referring to <FIG> and <FIG>, the safety device <NUM> differs from the safety device <NUM> in that a first rectangular notch <NUM> is provided at the midpoint of the first front edge <NUM>, a second rectangular notch <NUM> is provided at the midpoint of the first rear edge <NUM>, and the first rectangular notch <NUM> and the second rectangular notch <NUM> are identical in size.

<FIG> is a top view of another safety device according to some embodiments of the present disclosure. Referring to <FIG> and <FIG>, the safety device <NUM> differs from the safety device <NUM> in that a first sub heat locking hole <NUM> and a second sub heat locking hole <NUM> are symmetrically arranged on the central connecting line between the first heat locking hole <NUM> and the second heat locking hole <NUM>, and have the same symmetry axis as the first heat locking hole <NUM> and the second heat locking hole <NUM>.

<FIG> is a top view of another safety device according to some embodiments of the present disclosure. Referring to <FIG>, the safety device <NUM> differs from the safety device <NUM> in that the safety device <NUM> only is provided with the second heat locking hole <NUM> and the second sub heat locking hole <NUM>, and in that the first heat locking hole <NUM> and the first sub heat locking hole <NUM> are removed.

<FIG> is a top view of another safety device according to some embodiments of the present disclosure. Referring to <FIG> and <FIG>, the safety device <NUM> differs from the safety device <NUM> in that the safety device <NUM> is provided with a second heat locking hole <NUM>, and in that the first heat locking hole <NUM> is removed.

Claim 1:
A safety device (<NUM>, <NUM>, <NUM> ,<NUM>, <NUM>) for preventing overcurrent, comprising:
a first heat dissipation portion (<NUM>) made of an electrically conductive material;
a second heat dissipation portion (<NUM>) made of an electrically conductive material; and
a connecting part (<NUM>) made of an electrically conductive material arranged between the first heat dissipation portion (<NUM>) and the second heat dissipation portion (<NUM>), and provided with at least one heat locking hole (<NUM>, <NUM>),
wherein the connecting part (<NUM>) has a first heat locking portion (<NUM>), a fusing portion (<NUM>), and a second heat locking portion (<NUM>), and wherein the at least one heat locking hole (<NUM>, <NUM>) is located in the first heat locking portion (<NUM>) and/or the second heat locking portion (<NUM>),
characterized in that each of the first heat dissipation portion (<NUM>) and the second heat dissipation portion (<NUM>) is provided with a mounting pin (<NUM>, <NUM>) and at least an auxiliary pin (<NUM>, <NUM>), both mounting pins (<NUM>, <NUM>) and the auxiliary pins (<NUM>, <NUM>) being suitable for mounting the safety device (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) on a printed circuit board (<NUM>).