EP4654241A1

EP4654241A1 - Fuse holder device for high-power electrical circuit

Info

Publication number: EP4654241A1
Application number: EP25177902.1A
Authority: EP
Inventors: Erwan Guillanton; Laurent TRICHARD; Cesar MURGUIA
Original assignee: Aptiv Technologies AG
Current assignee: Aptiv Technologies AG
Priority date: 2024-05-21
Filing date: 2025-05-21
Publication date: 2025-11-26

Abstract

A fuse-holder device (1) is provided comprising a housing (2), a conductive plate (4), a fuse (3), a fastening element (5), and a spacer ring (18). The spacer ring (18) is interposed between the fastening element (5) and other conductive components and is made of an electrically insulating material whose deformation at 150°C is less than that of the plastic material of the housing (2).

Description

FIELD OF THE INVENTION

The present disclosure relates to the field of connecting devices for automotive applications, and more particularly to automotive connecting devices for fuse-boxes, such as engine fuse boxes. More particularly, the invention concerns the connection of a fuse in an electrical power circuit such as may be found in a Battery Electric Vehicle (BEV) or a Plug-In hybrid Electrical Vehicle (PHEV). An electrical circuit of this type may comprise one or more conductive plates, such as busbars or the like, and at least one fuse electrically connected such a conductive plate.

BACKGROUND

Automotive connecting devices are essential components in modern vehicles, providing electrical connections between various systems and devices. These connecting devices must be robust, reliable, and capable of withstanding harsh environmental conditions, including vibration, humidity, and extreme temperatures. Further, fuse-holder connecting devices are critical for overcurrent protection in automotive circuits.
A key challenge in automotive connecting device design is maintaining consistent electrical performance and safety over the vehicle's lifespan. Automotive environments can expose connecting devices to significant temperature variations, particularly in engine compartments or near high-power electronic components. Furthermore, heat generated by the passage of electrical current of high intensity through the connecting device itself can contribute to elevated temperatures. Many insulating materials used in connecting devices, especially plastics, can experience deformation or degradation at these elevated temperatures. This deformation can reduce the insulation distance between conductive elements, potentially leading to short circuits, signal degradation, or even fire hazards.
Traditional solutions to this problem include using connecting devices with housings made of higher-temperature plastics, employing more complex connecting device geometries to increase insulation distances, or incorporating cooling mechanisms. However, these approaches can add significant cost, weight, and complexity to the connecting device design. Higher-temperature plastics may be more expensive or have other undesirable properties, such as reduced flexibility or increased brittleness. Increased spacing leads to larger, bulkier connecting devices, which can be a problem in space-constrained automotive applications. Cooling mechanisms add cost, complexity, and potential points of failure.
Therefore, there is a need for an improved automotive fuse-holder connecting device that can reliably maintain electrical insulation at elevated temperatures without significant increases in size, weight, cost, or complexity.

SUMMARY OF THE DISCLOSURE

At least one of the problems posed by prior art devices can be at least partially resolved by a fuse-holder device comprising at least a housing, an electrically conductive fastening element, a conductive plate, a fuse and a spacer ring. The housing is formed from an insulating plastic material and comprises a passage passing through a fixing portion of the housing. This passage is extended by a sleeve extending from a first face of the fixing portion. The electrically conductive fastening element comprises a rod and a head. The rod passes through the passage, and the head is configured to be blocked by a second face of the fixing portion, on a side of the passage opposite that on which the sleeve is located. The conductive plate is mounted in the housing and comprises an opening through which the rod passes. The conductive plate is electrically insulated from the rod by the sleeve. The fuse comprises a conductive armature forming a cage having two terminals, each being passed through by the rod. A first terminal is in contact with the conductive plate and is insulated from the rod by the sleeve. A second terminal is configured to retain the fuse on the housing by means of a clamping element mounted on the rod. The rod passes through the spacer ring. The spacer ring is interposed between at least a first element included in a list comprising the head and the housing and a second element included in a list comprising the conductive plate and the first terminal. The spacer ring is made of an electrically insulating material whose deformation at 150°C is less than that of the plastic material of the housing.
This provides an automotive fuse-holder connecting device with improved high-temperature performance and enhanced electrical safety. It addresses the challenges posed by potential temperature rises in automotive environments while requiring only a minor design modification and the addition of a ring, that is a single, simple, and low-cost component.
According to an embodiment of the disclosure, the spacer ring is made of at least one ceramic material. This provides high heat resistance and dimensional stability, further enhancing the reliability of the insulation at high temperatures.
According to an embodiment of the disclosure, the spacer ring is made of at least one plastic material whose glass transition temperature is higher than that of the plastic material of the housing. This ensures that the spacer ring remains rigid and maintains its insulating properties even if the housing material softens at elevated temperatures, providing a cost-effective solution.
According to an embodiment of the disclosure, the spacer ring is made of at least one plastic material selected from the list comprising polyester and polyphenylene sulfide. These materials offer a good balance of high-temperature resistance of the fuse-holder device.
According to an embodiment of the disclosure, the spacer ring is interposed between the head and the conductive plate. This positioning provides effective insulation between the fastening element and the conductive plate, minimizing the risk of short circuits in automotive electrical systems.
According to an embodiment of the disclosure, the spacer ring comprises an open cylindrical wall. This geometry provides adequate insulation while minimizing material usage and weight, and adapting to the constraints of molding channel required to mold the housing, and more specifically the sleeve.
According to an embodiment of the disclosure, the spacer ring comprises a cylindrical wall with an edge comprising at least one notch. This geometry provides adequate insulation while minimizing material usage and weight, and adapting to the constraints of molding channel required to mold the housing, and more specifically the sleeve.
According to an embodiment of the disclosure, the conductive plate consists of a portion of busbar. This allows for a direct and robust electrical connection to the busbar, simplifying assembly and improving current carrying capacity.
A method of mounting a fuse-holder connecting device is also disclosed. This method comprises

at least one step consisting in providing a housing made of insulating plastic material, an electrically conductive fastening element with a rod and a head, a conductive plate and a fuse comprising a conductive armature with a first terminal and a second terminal,
at least one assembly step during which the housing, the conductive plate and the fuse are passed through by the fastening element, bringing the first terminal into electrical contact with the first terminal and keeping the fastening element insulated from the first terminal and the busbar.

During the assembly step a spacer ring is interposed between at least a first element included in a list comprising the head and the housing and a second element included in a list comprising the conductive plate and the first terminal, the spacer ring being made of a material whose deformation at 150°C is less than that of the plastic material of the housing. This provides a reliable and efficient method for assembling an automotive fuse-holder connecting device with improved high-temperature insulation.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure can be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, emphasis instead being placed upon an illustrating embodiment example of a fuse-holder device.

Fig. 1 is a schematic perspective exploded view of a fuse-holder according to an embodiment of the disclosure.
Fig. 2 is a schematic perspective sectional view of the fuse-holder of Fig. 1.
Fig. 3 is a detailed view of the spacer ring component of the fuse-holder of Figs. 1 and 2 highlighting its geometry.

DETAILED DESCRIPTION

Described below is an exemplary embodiment of a fuse-holder device. For example, such a fuse-holder device 1 is part of a fuse box. This fuse-holder device 1 comprises a housing 2 in which a fuse 3 is mounted in electrical contact with a conductive plate 4 such as a portion of a busbar. The housing 2, fuse 3 and conductive plate 4 are held together by a fastening element 5 having a rod 6 and a head 7. For example, the fastening element 5 is an M6 screw (see fig. 1).
For example, the housing 2 is made of a molded insulating plastic material. The housing 2 comprises a fixing portion 8 configured to receive, or at least partially accommodate, the fuse 3. For example, the fixing portion 8 is traversed by an essentially cylindrical passage 9. This passage 9 extends longitudinally, parallel to a longitudinal axis LA, essentially between a first face 10 and a second face 11 of the fixing portion 8. A sleeve 12 extends from the first face 10 of the fixing portion 8 on one side of the passage 9. On the other side of the passage 9, the housing 2 comprises a cavity 13 configured to receive and lock an end of the fastening element 5 (see fig. 2). For example, this end of the fastening element 5 corresponds to the head 7. In other words, the head 7 cannot pass through the fixing portion 8 because it is blocked in the cavity 13 located on the second face 11, opposite the first face 10 (with respect to the passage 9). Advantageously, the cavity 13 prevents the head 7 of the fastening element 5 from being touched, or at least from being touched too easily, by a user. Advantageously, the head 7 and cavity 13 have complementary shapes to limit rotation of the fastening element 5 when tightening a clamping element (not shown) mounted on the rod 6 (e.g., the clamping element is a bolt screwed onto the rod 6).
The fuse 3 comprises a conductive armature forming a cage with two electrically conductive terminals: a first terminal 14 is in contact with the conductive plate 4 (e.g., a busbar portion) and a second terminal 15 is intended to establish an electrical connection with a conductive element (not shown) mounted on the fixing portion 8, by means of the clamping element. The conductive armature can also be connected to the fixing element 5 while being located on the side of the head 7.
An electric current can therefore flow from the conductive plate 4 to the fastening element 5 through the fuse 3.
The sleeve 12 electrically isolates the conductive plate 4 from the fastening element 5 so that the conductive plate 4 does not come into direct electrical contact with the fastening element 5 (i.e., without passing through the fuse 3).
The sleeve 12 is integrally formed with the fixing portion 8 of housing 2. To mold the sleeve 12, channels are formed in the mold. For example, these channels comprise one main channel and five secondary channels. The secondary channels ensure even distribution of the plastic material injected into the mold to form the sleeve 12. It is important that the sleeve 12 should be free of defects to avoid short-circuiting between the conductive plate 4 (and/or the first terminal) and the fastening element 5.
To mount and secure the fuse 3 to the housing 2, the conductive plate 4 and the fuse 3 are placed on the fixing portion 8 (or in a recess provided therein), bringing the first terminal 14 into electrical contact with the conductive plate 4. The conductive plate 4 and the first terminal 14 are kept electrically insulated from the fixing portion 8 by the sleeve 12. The clamping element keeps the first terminal 14 in electrical contact with the conductive plate 4. For example, the conductive plate 4, the first terminal 14 and the second terminal 15 respectively have an opening 23, 24, 25 through which the rod 6 passes.
For example, if the clamping element is a bolt screwed on the rod 6, this bolt is tightened with an appropriate predefine torque. However, during the life of the vehicle on which the fuse-holder device 1 described here is mounted, temperature and vibration can induce deformations in the plastic material of the housing 2 and the sleeve 12. In particular, such deformations may occur (above 150°C, for example) at the sleeve 12, and more particularly at the base of the sleeve 12, i.e. at an area of the sleeve 12 on which the first terminal 14 and/or the conductive plate 4 may rest. There is therefore a risk of short-circuit between the conductive plate 4 and the fastening element 5.
To avoid this risk, a spacer ring 18 is inserted between the head 7 and the conductive plate 4. This is an advantageous configuration. However, other configurations are possible (with washer(s) inserted between the head 7 and the conductive plate 4, between the housing 2 and the conductive plate 4, between the head 7 and the first terminal 14, etc.).
Advantageously, this spacer ring 18 is made of an electrically insulating material whose deformation at 150°C is less than that of the plastic material of the housing 2. Many insulating materials can satisfy this requirement. However, the cost of the material used may also be a criterion for its choice. For example, the ring material is chosen from ceramic or plastic materials. If a plastic material is used, it has a higher glass transition temperature than the plastic material of the housing 2. An example of such a plastic material is a Polyesther or a Polyphenylene Sulfide - PPS - (e.g. PPS GF40). Advantageously, the spacer ring 18 has a cylindrical wall 19 (See Fig. 3). Advantageously, this wall 19 is open. In other words, the wall 19 has an open longitudinal slot 20 between its inner and outer faces. This slot 20 allows the passage of a main tab 16 resulting from the presence of the main channel used to inject the plastic material forming the sleeve 12. Similarly, the cylindrical wall 19 has an edge with several notches 22 (for example, five notches 22) , i.e. a serrated edge, corresponding to the secondary channels used to inject the plastic material forming the sleeve 12. l.e., these notches 22 allow the passage of secondary tabs 17 resulting from the presence of the secondary channels used to inject the plastic material forming the sleeve 12.

Claims

A fuse-holder device (1) comprising
- a housing (2) formed from an insulating plastic material and comprising a passage (9) passing through a fixing portion (8) of the housing (2), this passage (9) being extended by a sleeve (12) extending from a first face (10) of the fixing portion (8),

- an electrically conductive fastening element (5) comprising a rod (6) and a head (7), the rod (6) passing through the passage (9), and the head (7) being configured to be blocked by a second face (11) of the fixing portion (8), on a side of the passage (9) opposite that on which the sleeve (12) is located,

- a conductive plate (4) mounted in the housing (2) and comprising an opening (23) through which the rod (6) passes, the conductive plate (4) being electrically insulated from the rod (6) by the sleeve (12),

- a fuse (3) comprising a conductive armature forming a cage having two terminals (14, 15), each passed through by the rod (6), a first terminal (14) being in contact with the conductive plate (4) and being insulated from the rod (6) by the sleeve (12) and a second terminal (15) configured to retain the fuse (3) on the housing (2) by means of a clamping element mounted on the rod (6), characterized in that it comprises a spacer ring (18) through which the rod (6) passes and which is interposed between at least a first element included in a list comprising the head (7) and the housing (2) and a second element included in a list comprising the conductive plate (4) and the first terminal (14), the spacer ring (18) being made of an electrically insulating material whose deformation at 150°C is less than that of the plastic material of the housing (2).
The fuse-holder device (1) according to claim 1, in which the spacer ring (18) is made of at least one ceramic material.
The fuse-holder device (1) according to claim 1, in which the spacer ring (18) is made of at least one plastic material whose glass transition temperature is higher than that of the plastic material of the housing (2).
The fuse-holder device (1) according to claim 3, wherein the spacer ring (18) is made of at least one plastic material selected from the list comprising polyester and polyphenylene sulfide.
The fuse-holder device (1) according to one of the preceding claims, in which the spacer ring (18) is interposed between the head (7) and the conductive plate (4).
The fuse-holder device (1) according to one of the preceding claims, in which the spacer ring (18) comprises an open cylindrical wall (19).
The fuse-holder device (1) according to one of the preceding claims, in which the spacer ring (18) comprises a cylindrical wall (19) with an edge comprising at least one notch (22).
The fuse-holder device (1) according to one of the preceding claims, in which the conductive plate (4) consists of a portion of busbar.
Method of mounting a fuse-holder device (1) comprising
- at least one step consisting in providing
∘ a housing (2) made of insulating plastic material,

∘ an electrically conductive fastening element (5) with a rod (6) and a head (7),

∘ a conductive plate (4) and

∘ a fuse (3) comprising a conductive armature with a first terminal (14) and a second terminal (15),

- at least one assembly step during which the housing (2), the conductive plate (4) and the fuse (3) are passed through by the fastening element (5), bringing the first terminal (14) into electrical contact with the first terminal (14) and keeping the fastening element (5) insulated from the first terminal (14) and the busbar,
Characterized in that during this assembly step a spacer ring (18) is interposed between at least a first element included in a list comprising the head (7) and the housing (2) and a second element included in a list comprising the conductive plate (4) and the first terminal (14), the spacer ring (18) being made of a material whose deformation at 150°C is less than that of the plastic material of the housing (2).