FR3058840A1 - FEMALE POWER ELECTRICAL CONTACT - Google Patents

Abstract

A female electrical contact (10) adapted to be integrated with a connector for connecting electric charging cables of hybrid or electric vehicles comprises a base (16) and a socket (18) extending continuously along a longitudinal central axis (A). ), the base (16) being intended to be connected to an electric cable, the socket (18) being provided to receive a male electrical contact (46), the base (16) and the socket (18) being made of a conductive metal; the sleeve (18) has at least two short elastic tongues (28) and two long elastic tongues (30), the tongues (28, 30) being electrically conductive, each tongue (28, 30) extending along the central axis longitudinal (A) from the base (16) to a free end (38, 40), the short tongues (28) and the long tongues (30) being distributed alternately around the longitudinal central axis (A), each free end (38, 40) comprising a contact surface (34, 36) provided to exert a contact force on a male electrical contact (46) inserted in the socket (18) along the longitudinal central axis (A), the long tabs (30) being longer longitudinally than the short tabs (28),

Description

Holder (s): DELPHI INTERNATIONAL OPERATIONS LUXEMBOURG S.A R.L. Limited liability company.

Extension request (s)

Agent (s): DELPHI FRANCE SAS Simplified joint-stock company.

FR 3 058 840 - A1 (54) FEMALE POWER CONTACT (© A female electrical contact (10) intended to be integrated into a connector for connecting electric charging cables for hybrid or electric vehicles comprises a base (16) and a socket (18) extending in continuity along a longitudinal central axis (A), the base (16) being provided to be connected to an electric cable, the socket (18) being provided to receive a male electrical contact (46), the base (16) and the socket (18) being made of a conductive metal; the socket (18) comprises at least two short elastic tongues (28) and two long elastic tongues (30), the tongues (28, 30) being electrically conductive, each tab (28, 30) extending along the longitudinal central axis (A) from the base (16) towards a free end (38, 40), the short tabs (28) and the long tabs (30) being distributed alternately around the axis c longitudinal (A), each free end (38, 40) comprising a contact surface (34, 36) provided to exert a contact force on a male electrical contact (46) inserted in the socket (18) along the axis longitudinal center (A), the long tongues (30) being longer longitudinally than the short tongues (28),

DP-322836

FEMALE POWER CONTACT

TECHNICAL AREA

The invention relates to the field of automotive connectors. More particularly, the invention relates to a female electrical power contact for a motor vehicle.

TECHNOLOGICAL BACKGROUND OF THE INVENTION

Power connectors can be used in particular in hybrid and electric vehicles to connect electric charging cables and / or different components of a power circuit (converters, batteries, motors, etc.). Such connectors must be able to withstand currents of up to 63 Amps, 97 Amps, or even 125 Amps or more in the future. In order to withstand high current densities, the male and female electrical power contacts used in these connectors must be relatively large.

During the recharging of electric or hybrid vehicles by the electric recharging cables, safety devices prevent the disconnection of these cables. However, failure of these devices is still possible. This is why, according to the IEC 62196 standard, it is also required to test the robustness of the charge connectors in a particular degraded mode. It is particularly requested to check the robustness of the charge connectors during multiple connection / disconnection cycles of the charge connector when the latter is still energized. When disconnected under voltage, electrical arcs degrade the electrical terminals of the charge connectors, eventually leading to the failure of these connectors.

It is therefore important to offer a new solution to these problems.

SUMMARY OF THE INVENTION

A female electrical contact, intended to be integrated into a connector for connecting electric charging cables for hybrid or electric vehicles, comprises a base and a socket extending in continuity along a longitudinal central axis, the base being provided to be connected to an electric cable, the socket being designed to receive a male electrical contact, the base and the socket being made of a conductive metal. The socket has at least two short elastic tongues and two long elastic tongues, the tongues being electrically conductive. Each tongue extends along the longitudinal central axis from the base to a free end, the short tongues and the long tongues being distributed alternately around the longitudinal central axis, each free end comprising a contact surface provided for exert a contact force on a male electrical contact inserted into the socket along the longitudinal central axis, the long tongues being longer longitudinally than the short tongues, the female electrical contact comprising a transition zone between the free ends of the short tongues and the free ends of the long tabs, allowing the male electrical contact to be in contact only with one or more long tabs, without being in contact with a short tab, during an operation for removing the male electrical contact so that when disconnected under load, the current flows only by means of at least one long tab resting on the male electrical contact, the circulating current becoming weaker than the nominal charging current thus limiting the risk of electric arc.

Long elastic tabs can be two to three times longer than short elastic tabs. Short elastic tabs can have a contact force of at least 8 times greater than long elastic tabs. The short elastic tongues can have a contact resistance at least twice lower than the long elastic tongues. The contact surfaces of the elastic short tabs can be coated with Silver. The contact surfaces of the long elastic tabs can be covered with Nickel.

The female electrical contact can comprise three elastic short tongues and three elastic long tongues, the three elastic short tongues and the three elastic long tongues being able to be regularly distributed in a circle equidistant from the longitudinal central axis. The short elastic tongues can have a length of between 10 and 15 millimeters. The long elastic tabs can have a length of between 20 and millimeters. The short elastic tongues and the long elastic tongues may differ geometrically only in their length.

BRIEF DESCRIPTION OF THE DRAWINGS

Other characteristics, objects and advantages of the invention will appear on reading the detailed description which follows, and with reference to the appended drawings, given by way of non-limiting example and in which:

- Figure 1 shows schematically in perspective, the body of a female electrical power contact according to the invention.

Figure 2 shows schematically in perspective, the female electrical power contact of Figure 1 into which is inserted a male electrical power contact when charging a vehicle.

- Figure 3 shows schematically in perspective, the female electrical power contact of Figure 1 in which the male electrical power contact is in the transient phase of disconnection with the female electrical contact.

- Figure 4 is a graph showing the evolution of the electrical resistance of contact between the tabs of the female contact and the male electrical contact inserted as a function of the contact force exerted by the tabs of the female contact on the male contact, and also depending on the surface coating of the tabs.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

According to Figure 1 an exemplary embodiment of a female electrical contact 10 of power is shown. This electrical contact 10 is in particular intended to be integrated into a power connector which can be used in particular in hybrid and electric vehicles for connecting electric charging cables.

The female electrical contact 10 extends longitudinally in a direction D between a rear end 12 and a front end 14. The rear end 12 is intended to be connected to a cable (not shown) by welding or crimping, for example. The front end 14 is provided to guide the insertion of a male electrical contact.

The female electrical contact 10 comprises, from the rear to the front, a base 16 and a socket 18. A shoulder 20 is arranged between the base 16 and the socket 18 so as to be able to fit a protective sleeve on the socket 18 coming in continuity from the base 16. The female electrical contact 10 consists of an electrically conductive material such as a copper alloy (for example CuNiPblP).

The base 16 has a fixing end 22 intended to be connected to the cable. It also has a groove 24, between two ribs 26, intended to receive an O-ring (not shown).

The socket 18 being designed to receive a male electrical contact. The socket 18 comprises six elastic tongues 28, 30 formed integrally with the base 16 and distributed around a longitudinal central axis A parallel to the direction D. The six tongues 28, 30 are electrically conductive. The tabs are made of an electrically conductive material such as a copper alloy (e.g. CuNiPblP).

Each elastic tongue 28, 30 extends longitudinally from the base 16 towards a free end 38, 40. The six tongues 28, 30 are distributed in a first group of three short tongues 28 and a second group of three long tongues 30. The three short tabs 28 and the three long tabs 30 are regularly distributed in a circle equidistant from the axis A. The short tabs 28 and the long tabs 30 are distributed so that each short tab 28 is arranged between two long tabs 30. And therefore also, each long tongue 30 is arranged between two short tongues 28. The tongues 28, 30 are spaced from their neighboring tongues 28, 30 by an inter-tongue space 32. The inter-tongue spaces 32 are therefore six in number . The inter-tab spaces 32 are generally of the same dimension.

According to the embodiment shown, the long tongues 30 differ from the short tongues 28 only in their length, the long tongues 30 being longer longitudinally than the short tongues 28. Preferably, the short tongues 28 are all of the same length. Preferably, the long tongues 30 are all of the same length. The length, according to Tax A, of the long tongues 30 is generally two to three times greater than the length of the short tongues 28. By way of example, the short tongues 28 measure approximately ten millimeters while the long tongues 30 measures about thirty millimeters.

The short tongues 28 and the long tongues 30 are slightly inclined (for example by 3 ° relative to the longitudinal direction D), from the rear towards the front, towards the inside of the socket 18 relative to the direction D so as to be pushed elastically radially outwards from the socket 18, when a male contact of a male connector is inserted between the tongues 28, 30. This inclination gives the tongues 28, 30 elastic properties allowing 'exert a contact force on a male contact inserted in the socket 18. Due also to the inclination, the contact surfaces 34, 36 of the tongues 28, 30 are located at the free ends 38, 40 of the tongues 28, 30. More specifically, the contact surfaces 34, 36 are located on the internal surface 42, 44 of each free end 38, 40 of the tongues 28, 30 directed towards the axis A, the said internal surface 42, 44 t provided for making electrical contact with a male electrical power contact.

According to Figure 2, a male electrical contact 46 of power is inserted into the socket 18 of the female electrical contact 10 along the longitudinal central axis A. The male contact 46 is sufficiently inserted into the socket 18 so that as well the contact surfaces 36 of the long tongues 30 that the contact surfaces 34 of the short tongues 28 come to bear on the male contact 46. This configuration is that for which an electric charge current can flow from the male electric contact 46 towards the contact electric female 10 when charging a vehicle. The vehicle is charged at constant voltage.

As the short tongues 28 differ from the long tongues 30 by their length, the difference in contact force exerted by the tongues 28, 30 of the embodiment shown is proportional to the length of the tongues 28, 30. The contact force exerted decreases by cubically with the length of the tongues 28, 30. The longer the tongues 28, 30, the lower the contact force. In this case, the long tongues 30 being overall a little more than twice as long as the short tongues 28, their contact force on the male contact 46 is therefore at least eight times weaker. For example, the short tongues 28 measuring approximately ten millimeters can exert on the male contact 46 a force of 6.5 Newtons while the long tongues 30 measuring twenty millimeters can exert on the male contact 46 a force of 0.8 Newton . It will therefore be understood that, according to the invention, the short tongues 28 essentially guarantee the mechanical maintenance of the male contact 46 in the socket 18 while the long tongues 30 serve as an insertion guide for the male contact 46 in the socket 18.

In the configuration illustrated in FIG. 2, an electric charge current flows from the male electric contact 46 to the female electric contact 10. The electric charge current le, flowing in the male contact 46 represented by a cylindrical bar, must be distribute through the three short tongues 28 and the three long tongues 30. This distribution of the electrical charge current le in the tongues 28, 30 is made in proportion to the value of the electrical contact resistance of the tongues 28, 30. The short tongues 28 being different from the long tongues by their length, the electrical contact resistance of the tongues 28, 30 is proportional to the length of the tongues 28, 30. The electrical contact resistance increases almost linearly with the length of the tongues 28, 30. In this case, the long tongues 30 being overall a little more than twice as long as the lan short lookouts 28, their electrical contact resistance is therefore at least twice as great. For example, the short tongues 28 generally measuring around ten millimeters may have an electrical contact resistance of the order of half a milli-ohm, while the long tongues 30 measuring around twenty millimeters may have an electrical contact resistance on the order of a milli-ohm. It will therefore be understood that according to the invention, the electric charging current flows essentially through the short tongues 28.

According to FIG. 3, the male electrical contact 46 is in the disconnection phase with the female electrical contact 10. According to the configuration shown, the male contact 46 has been moved in the direction D, from its initial position provided for charging the vehicle, that is to say from its position illustrated through FIG. 2, to the free ends 40 of the three long tongues 30. The male electrical contact 46 is therefore still in contact with the socket 18 by only through the intermediary of the three tongues long 30. An electric current, called electric disconnection current ld, flows through the male electrical contact 46 and long tabs 30 of the female electrical contact 10.

In order to reproduce the load cut-off system failure test, the constant voltage load is maintained in this configuration. According to this configuration, the only possible path allowing the electric discharge current ld to flow from the male electrical contact 46 to the female electrical contact 10, is that through the three long tongues 30. The three long tongues 30 not only have a force contact resistance but above all a contact resistance two to three times higher than that of the three short tabs 28. The contact resistance of the three long tabs 30 is dimensioned so that the electric current that of disconnection ld is two to three times more weak, or even more, than the electric charge current le. Consequently, this disconnection current ld is not optimal for charging the vehicle. It will be understood that this configuration is not a normal charging configuration.

The major technical effect of this invention is to be able to reduce the electric charge current flowing in the electrical contacts before the complete removal of the male electrical contact 46 so as to minimize the effects of electric arcs. The female electrical contact 10 therefore comprises a transition zone 48 comprised between the free ends 38 of the short tongues 28 and the free ends 40 of the long tongues 30. The transition zone is a zone for which the current flowing in the male electrical contact and the female electrical contact 10 is reduced. Part of the three long tongues 30 therefore serves as a transition zone 48 to reduce the current when the male electrical contact 46 is disconnected with the female electrical contact 10 in order to limit the appantation of electric arcs. In this transition zone 48, the male contact 46 can only be only in contact with at least one long tongue 30. In this transition zone 48, the male electrical contact 46 is not in contact with a short tongue 28 In other words, in the transition zone 48, the male electrical contact 46 is only in contact with one or more long tongues 30, without being in contact with a short tongue 28.

According to the embodiment shown, the male electrical contact 46 is in contact with the three long tongues 30, but is not in contact with the three short tongues 28. In this disconnection configuration under load, the disconnection current Id flows transiently only through the three long tabs 30 bearing on the male electrical contact 46, the circulating disconnection current becoming weaker than the electrical charging current thus limiting the risk of electric arc during the complete removal of the male electrical contact 46 .

The limitation of electric arcs not only avoids the deterioration of the electrical contacts but also protects an individual carrying out this disconnection.

Without this transition zone 48, the electric current before disconnection would have been that optimum for the load, that is to say for example at least 63 amperes. In this case, the sudden disconnection under voltage would have generated an electric arc phenomenon leading to the degradation of the electrical contacts.

According to FIG. 4, two curves Cni, Cag represent the evolution of the electrical contact resistance between the tongues 28, 30 of the female electrical contact 10 and the male electrical contact 46 inserted as a function of the contact force exerted by the tongues 28 , 30 from female contact 10 on male contact 46.

The abscissa axis F represents the contact force of a tongue 28, 30. The values indicated in Newton are therefore proportional to the length of the tongue 28, 30. The ordinate axis O represents the ohmic value of the resistance of contact of a tongue 28, 30 as a function of its contact force, that is to say as a function of the length of the tongue 28, 30.

The two curves Cni, Cag are each produced with a different surface coating on the tongues 28, 30.

The first curve Cag is obtained when the contact surface 34, 36 of a tongue 28, 30, that is to say the zone intended to come to establish an electrical contact with the male electrical contact 46 of power, is completely covered with a layer of noble metal, in this case silver. For example, the noble metal layer is 40pm thick.

The second curve Cni is obtained by covering the contact surface

34, 36 with a tab 28, 30 with nickel.

From these two curves Cni, Cag, it will be understood that covering the contact surfaces 34 of the short tongues 28 with silver makes it possible to reduce the contact resistance. For example, a short tongue 28 covered with Silver, of a length such that the contact force is of the order of 6.5 Newton has an electrical contact resistance of the order of a quarter of a milli- ohm. On the other hand, by way of example, a long tab 30 covered with nickel of a length such that the contact force is of the order of one Newton has an electrical contact resistance of the order of 2.5 milli-ohms .

In a particular embodiment, the contact surfaces 34 of the three short tabs 28 are entirely covered with Silver, while the contact surfaces 36 of the three long tabs 30 are entirely covered with Nickel.

Alternatively, the three short tongues 28 as well as the base 16 of the female electrical contact 10 may be entirely covered with Silver in order to present the lowest electrical resistance to optimize the electric charge current le, while the three long tongues 30 can be entirely covered with Nickel in order to present the highest electrical resistance to minimize the disconnection current Id during a disconnection under voltage.

Also, the contact surfaces can be only partially covered with Silver or Nickel.

Other metals intended to cover the tabs 28, 30 are possible, the aim being to reduce the electrical contact resistance of the short tabs 28 as much as possible and to maximize the electrical contact resistance of the long tabs 30.

The lengths along the longitudinal central axis A and proportions of the short tongues 28 and of the long tongues 30 described through the described embodiment are not limiting. Shorter tabs 28 associated with much longer tabs 30 also make it possible to obtain the desired result, namely to minimize the formation of electric arcs during disconnection under load.

Also, the geometric shape of the tongues 28, 30, their thickness as well as the material chosen, can be as many adjustable parameters to obtain the contact resistance and the desired contact force of the tongues 28, 30.

Although the invention has been described through an embodiment of a female electrical contact 10 comprising three short tongues 28 and three long tongues 30, other embodiments comprising at least two short tongues 28 and two tongues long 30 arranged around the axis A and alternately are possible. The long tabs 30 must serve as a guide for inserting the male electrical contact 46 and the short tabs 28 for maintaining the male electrical contact 46, in addition to their electrical role when charging the vehicle and when disconnected under voltage of the male electrical contact 46 with the female electrical contact 10.

Claims (10)

1. Female electrical contact (10) intended to be integrated into a connector for connecting electric charging cables for hybrid or electric vehicles, the female electrical contact (10) comprising a base (16) and a socket (18) extending in continuity along a longitudinal central axis (A), the base (16) being provided to be connected to an electric cable, the socket (18) being provided to receive a male electrical contact (46), the base (16) and the socket (18) being made of a conductive metal, characterized in that the socket (18) comprises at least two short elastic tongues (28) and two long elastic tongues (30), the tongues (28, 30) being electrically conductive ; each tab (28, 30) extending along the longitudinal central axis (A) from the base (16) towards a free end (38, 40), the short tabs (28) and the long tabs (30) being distributed by alternately around the longitudinal central pin (A), each free end (38, 40) comprising a contact surface (34, 36) provided to exert a contact force on a male electrical contact (46) inserted in the socket (18 ) according to longitudinal central tax (A), the long tongues (30) being longer longitudinally than the short tongues (28), the female electrical contact (10) comprising a transition zone (48) between the free ends (38) short tongues (28) and the free ends (40) of the long tongues (30), allowing the male electrical contact (46) to be in contact only with one or more long tongues (30), without being in contact with a short tongue (28), during an opera tion of withdrawal of the male electrical contact (46) so that during a disconnection under load, the current (Id) flows transiently only through at least one long tab (30) bearing on the male electrical contact (46 ), the circulating current (Id) becoming lower than the nominal load current (le) thus limiting the risk of electric arc. 2. Female electrical contact (10) according to claim 1 characterized in that the long elastic tongues (30) are two to three times longer than the short elastic tongues (28). 3. Female electrical contact (10) according to any one of the preceding claims, characterized in that the short elastic tongues (28) have a contact force at least 8 times greater than the long elastic tongues (30). 4. Female electrical contact (10) according to any one of the preceding claims, characterized in that the short elastic tongues (28) have a contact resistance at least twice lower than the long elastic tongues (30). 5. Female electrical contact (10) according to any one of the preceding claims, characterized in that the contact surfaces (34) of the short elastic tabs (28) are covered with Silver. 6. Female electrical contact (10) according to any one of the preceding claims, characterized in that the contact surfaces (36) of the long elastic tabs (30) are covered with Nickel. 7. female electrical contact (10) according to any one of the preceding claims, characterized in that it comprises three short tongues (28) elastic and three long tongues (30) elastic; the three short elastic tongues (28) and the three long elastic tongues (30) being regularly distributed in a circle equidistant from the longitudinal central axis (A). 8. Female electrical contact (10) according to any one of the preceding claims, characterized in that the short elastic tongues (28) have a length of between 10 and 15 millimeters. 5 9. Female electrical contact (10) according to any one of the preceding claims, characterized in that the long elastic tongues (30) have a length of between 20 and 30 millimeters. 10. Female electrical contact (10) according to any one of 10 previous claims characterized in that the short elastic tongues (28) and the long elastic tongues (30) differ geometrically only in their length. 2/2