Note: Descriptions are shown in the official language in which they were submitted.
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LAMINOUS MULTI-POLYMERIC HIGH AMPERAGE OVER-MOLDED CONNECTOR
ASSEMBLY FOR PLUG-IN HYBRID ELECTRIC VEHICLE CHARGING
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Field of the Invention
The present invention is directed to an electrical connector for supplying
power to an electric
vehicle and more particularly to such a connector having improved resistance
to water in the
environment and improved user-friendliness.
Description of Related Art
Electric vehicles are increasingly receiving attention. These include plug-in
hybrid vehicles
such as the Chevrolet Volt and purely electric vehicles such as the Nissan
Leaf.
Electrical connectors for recharging the batteries of electric vehicles are
standardized in
North America by Society of Automotive Engineers (SAE) standard SAE J1772.
Other
applications, such as forklifts and industrial equipment, may also adopt that
standard.
According to that standard, the front of the connector has a standardized
shape and five pins
in a standardized layout, so that all connectors work with all electric
vehicles. The five pins are
two AC power pins, a ground pin, a proximity detection pin and a control pilot
pin. Regarding
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the rest of the connector, the manufacturer of each connector has some
discretion. Known
connectors typically use spring latches to secure the connector to the vehicle
during charging.
Since such connectors are typically used outdoors, environmental
considerations, such as
water, must be taken into account. For example, water may get into the
mechanism of the spring
latch and cause corrosion or other degradation. The usual way to prevent such
degradation is to
use a rubber seal to protect the spring latch. However, seals fail.
There are also the problems of using the connector at night, when the motorist
may not be
able to see properly, and of letting the motorist know when the connector has
been fully and
properly inserted.
Moreover, known connectors are typically manufactured from multiple parts. As
a
consequence, they can be expensive to manufacture and prone to failure.
To date, all solutions currently available in the Electric Vehicle (EV) market
space are
constructed from two halves (or clamshells) which are mechanically assembled
with tamper-
resistant fasteners such as TorxTm screws. The old or current SAE J1772
mechanically
assembled connectors currently allow water to enter the handle assembly,
leading to an
opportunity for ice and debris to become trapped. Additionally, the clamshells
add a bulky
appearance at the handle and overall body, which is driven by the additional
mechanical features
required to resist vehicle roll-over and crush requirements, as stated in UL
2251. These current
devices are suitable for garage and indoor applications. When used outdoors,
these clam-shell
designs may exhibit shorter life cycles due to exposure to the elements.
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Summary of the Invention
It is therefore an object of the invention to address the above concerns.
It is another object of the invention to provide a low-cost, attractive,
ergonomic and adaptable
solution.
To achieve the above and other objects, the present invention is directed to a
connector
having at least one of the following features.
The spring latch is not sealed; instead, the connector body has holes allowing
water entering
the spring latch mechanism to drain harmlessly out of the connector. A forward-
facing LED or
other light source acts as a flashlight. Once the connector is connected, the
forward-facing LED
is switched off, and a rear-facing LED or other light source is switched on to
confirm that the
connector is connected and capable of charging the vehicle,
The connector is produced by overmolding. For example, the connector can be
produced in a
three-layer configuration, with potting material, a premold, and a one-piece
overmold. Each of
the layers can be formed of a different material that gives it the properties
needed for its location
in the connector. The modular design allows for faster product updates and a
common platform
for product diversification.
The above features can be combined in any way.
The problem being solved by this invention is offering the EV (electric
vehicle) market space
(such as Original Equipment Manufacturers (OEM) and Electric Vehicle Supply
Equipment
(EVSE) manufacturers) a ruggedized and integrated overrnolded SAE Jl 772
connector and cable
assembly solution that offers reduced life-cycle costs and improved product
reliability, and that
also reduces the risks of tampering and vandalism associated with mechanical
locking features
and hardware (such as Torxm Screws). This over-molded solution offers
exceptional
environmental protection from the extreme environmental elements which may
include: water,
ice, dust, ultra-violet rays, oils and automotive fluids.
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Brief Description of the Drawings
A preferred embodiment will be set forth in detail with reference to the
drawings, in which:
Figures 1-8 are various views of the connector according to the preferred
embodiment and of
various components thereof;
Figures 9A-21 are views showing steps in the production of the connector of
Figures 1-8; and
Figures 22A-22D are views of a connector according to a variation of the
preferred
embodiment.
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Detailed Description of the Preferred Embodiment
A preferred embodiment will be set forth in detail with reference to the
drawings, in which
like reference numerals refer to like elements throughout.
As shown in Figures 1-8, the connector 100 according to the preferred
embodiment includes
a connector front piece 102 with a plurality of pins 104, 106, 108, 110, 112.
In the preferred
embodiment, the connector front piece 102 and the pins 104-112 follow the
standard SAE J1772.
The pins 104-112 are electrically connected to a cable 114 at a location which
is sealed inside of
the connector front piece 102 with potting 116. A connector body 118 is formed
over the
connector front piece 102 and the cable 114 by a premold 120 and an overmold
122. The
premold 120 and the overmold 122 are formed with ridges 124, 126 to increase
the strength of
the connector body 118. The connector body has a latch area 128 with a spring
latch 130 having
a pin 132 and a spring 134.
A first LED or other light 136 can be provided to act as a flashlight, so that
the user can use
the connector at night in situations of poor lighting. A second LED or other
light 138 can be
provided on the back to indicate when the proper electrical connection between
the connector and
the vehicle is achieved, at which time the first LED is switched off.
Circuitry 140, such as a
printed circuit (PC) board to be described below, is provided for controlling
the LED's.
The latch area 128 does not have to be sealed against water. Instead, water
entering the latch
area 128 exits through holes 142. As shown, there are three holes 142 on
either side of the latch
area 128, extending through the overmold 122 and into the latch area 128. The
holes 142 are
open to the latch area 128 at a bottom surface 144 of the latch area 128 so
that there will be no
places for the water to accumulate. However, any suitable number and
configuration of holes
can be used instead of, or in addition to, the holes shown.
For example, in use in a rainy situation, rain water incident on the connector
100 enters the
latch area 128 by flowing around the spring latch 130. Instead of accumulating
in the latch area
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128, the water exits the latch area 128 through the holes 142. As noted above,
the holes 142 are
positioned relative to the bottom surface 144 of the latch area 128 so that
all of the water drains
out of the latch area 128 rather than forming puddles below the holes 142.
The holes 142 are shown as extending horizontally to facilitate overmolding.
The left and
right components of the mold used in the overmolding can have projections
corresponding to the
holes 142 and thus form the holes 142. After the overmolding process, the left
and right
components are pulled off in a horizontal direction to pull the projections
out of the holes 142
thus formed. However, the configuration of the holes 142 can be varied in
accordance with
various manufacturing techniques. For example, in different manufacturing
techniques, the holes
142 could slope downwardly from the latch area 128 or even extend vertically
downwardly from
the latch area 128. Moreover, holes 142 can be formed in any other suitable
manner, e.g., by
drilling.
Still other configurations are possible. For example, the latch area 128 could
have a bottom
surface 144 that is flat or that is crowned to urge water out through the
holes 142. Also, while
the holes 142 are shown as elongated, they could have any suitable shape,
e.g., round.
The preferred embodiment provides an overmolded, ruggedized, and robust high-
amperage
SAE J1772 connector assembly. The production of the preferred embodiment
begins with an
insert molded SAE J1772 10 amp through 90 amp connector, shown in Figures 9A
and 9B as
146, made of a polycarbonate material with a UL94 V-0 flame rating with an
environmental (f1)
ultra-violet rating and a relative thermal index (RTI) equal to or exceeding
100 for electrical and
physical impact and strength characteristics, as specified by the standard UL
2251.
The SAE J1772 connector body architecture 146 is that of a rigid body design,
which
incorporates mechanical features promoting cross-linking adhesion and/or
enabling mechanical
bonding and mechanical locking features with the premold 120 and the overmold
122. These
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mechanical features may include flow-through channels, pierced holes, raised
joggles or
ridgelines.
The connector body contains five 353 1/2 hard brass contacts 104, 106, 108,
110, 112, as
described above, which can be silver or gold plated. The two Size 8 power
contacts 104, 112
incorporate elliptically wound high amperage and low insertion force internal
helical springs 148
to enable higher amperage with reduced opportunities for heating due to micro-
arcing, as well as
offering additional opportunities of success for reverse compatibility to
vehicle inlets (IAW SAE
1772) manufactured by other manufacturers. These internal helical springs 148
also aid in
accommodating the natural tendencies of process shift over time. The springs
148 can be
configured as a plurality of toroidal springs, as shown, e.g., in U.S. Patent
No. 4,810,213 to
Chabot,
The insert molded SAE 11772 connector body 146 also incorporates a flame
retardant (FR)
UL listed closed cell gasket 150 on the mating face to aid in the prevention
of attack on the
contacts from corrosive gases such as carbon dioxide, sulfur dioxide, and
hydrogen sulfide.
The connector body 146 is then assembled to an FFSO UL listed cable 114, shown
by itself
in Figure 10, by means of a soldering operation to accommodate the pin-out
diagram as specified
in SAE 31772, as shown in Figure 11. The soldered contacts of the insert
molded SAE 31772
allow for improved cable retention of the overall assembly as well as reduced
opportunities for
micro-arcing and stray strands, which could lead to risks of shorts and ground
faults, reducing the
life cycle of the product. Additionally, soldered contacts provide for an
additional level of
defense to deter the wicking and capillary effect of moisture absorption at
the exposed contacts.
Water and moisture absorption, or wicking, accelerates copper corrosion and
reduces the product
life cycle, which may result in higher amperage draw from the branch circuit
resulting in
excessive heat and customer dissatisfaction.
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An environmentally sealed micro-switch sub assembly 152 is soldered to an FR-4
PC UL
listed PC board 154, which incorporates one 150 Ohm '72 watt resistor 156 and
one 300 Ohm 1/2
watt resistor 158, to implement the circuitry 140 described above as a micro-
switch assembly. A
grommet, shown in Figures 13A and 13B as 164, is then added to the micro-
switch sub-assembly
140 and assembled into position, as shown in Figure 14. The grommet is
manufactured from a
polymeric molding compound which is UL94 V-1 flame rating with an
environmental (fl) ultra-
violet rating and a relative thermal index (RTI) equal to or exceeding 90 for
electrical and
physical impact and strength characteristics, as specified by UL 2251. The
assembly 152 and
board 154 are attached to the connector body 146, as shown in Figure 15, by
means of soldering
the two flying leads (proximity and ground) 160, 162 to the proximity and
ground pin contacts
106, 108, enabling the DC pulse signals required by the SAE J1772 Standard.
This PC board 154
also provides for the silver path provisions to incorporate LED signals for
charge and flashlight
requirements that may be activated or required by the EVSE.
When the soldering operation has been completed, the connector body 146, PC
board
assembly 154, and cable 114 are environmentally and dielectrically potted, as
shown in Figures
16A and 16B, with a two-part potting compound 166 that has a UL94 HB or V-0
flame rating
and a relative thermal index (RTI) equal to or greater than 90 for electrical,
physical impact and
strength characteristics, as specified by UL 2251, to form the potting 116.
This potting compound
166 will then be cured either by overnight stall, or with a heat assist
manufacturing aid. The
FFSO electric vehicle cable jacket, insulated conductors and soldered
connections will be
encapsulated with this two part potting compound.
This potting compound 166 provides for the first level of defense to deter the
wicking and
capillary effect of moisture absorption at the exposed contacts. Copper
stranding can, over time,
enable a capillary effect in which moisture wicks from the exposed contact
area into the copper
stranding which accelerates copper corrosion and reduces the product life
cycle, which may
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result in higher amperage draw from the branch circuit resulting in excessive
heat and customer
dissatisfaction. The potting compound 166 also offers dielectric properties,
further insulating the
assembly from potential in air arcing between the power contacts and ground.
This potting
compound 166 is the foundation in which the additional polymeric materials
will use for
additional structure and support within the design.
After the two-part environmentally and dielectrically potted compound 166 has
cured and
outgassed completely to form the potting 116, a pre-mold 120 will then be
molded over the sub-
assembly that includes the connector body 146, the FFS0 electric vehicle cable
114, and the
potted contact, as shown in Figure 17. The pre-mold is a high impact Polyamide
(PA6 or PA66)
based material with a UL94 V-0 flame rating and a relative thermal index (RTD
equal to or
greater than 100. Other specially engineered compounds, such as glass filled
polyethylene
terephthalate (PET), acrylonitrile butadiene styrene (ABS), thermoplastic
elastomer (TPE),
thermoplastic vucanizate (TPV), or high impact polypropylene (HIPP), can be
used. The pre-
mold 120 encapsulates the subassembly, providing for the 'backbone' of the
architecture, as well
as adding additional environmental and dielectric properties to the overall
SAE J1772 molded
connector assembly system. The pre-mold 120 includes holes 168 corresponding
to the holes
142 of the finished product.
The pre-mold architecture is that of a rigid body design, which incorporates
mechanical
features promoting either cross-linking adhesion and/or enabling mechanical
bonding and
mechanical locking features of an outer 'over-mold skin' layer. These
mechanical features may
include flow-through channels, raised joggles or ridgelines, or depressed
valleys and flow-
through T-channels.
The over-mold or skin, shown in Figure 18 as 122, is for user interface,
impact energy
absorption, abrasion resistance, fluid and gasoline resistance and overall
ultra-violet (UV)
protection of the overall SAE j1772 molded connector assembly system. The
overmold material
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of the SAE J1772 Connector Assembly has a UL94 HB or V-1 flame rating and a
relative
thermal index (RTI) equal to or greater than 90 for electrical, physical
impact and strength
characteristics, as specified by UL 2251. Alternate thermoset materials, such
as EPT, EPDM, and
silicone or liquid silicone injection, may also be incorporated to accommodate
the physical and
performance requirements of the outer skin.
Once the system is completely molded, a latch arm 130 manufactured from a
polymeric
material such as polycarbonate (PC) with a UL94 V-0 flame rating, an
environmental (fl) ultra-
violet rating and a relative thermal index (RTI) equal to or exceeding 100 for
electrical and
physical impact and strength characteristics, as specified by UL 2251, is
attached. This latch arm
is attached by means of a molded or stainless steel (300 Series) pin. The
latch provides for the
mechanical interlock to the SAE J1772 vehicle inlet as well as the mechanical
lever activating
the micro-switch sub-assembly prior to commencing charging as well as upon
completion of
charging. The steps of attaching the latch arm include inserting the latch
spring 134 into the latch
area 128, as shown in Figure 19; inserting the latch arm 130 over the spring
134 into the latch
area 128, as shown in Figure 20; and inserting the latch pin 132, as shown in
Figure 21.
Additionally, the market currently only offers 30 AMP and 75 AMP listed
assemblies, which
are mostly governed by the cable and contact size. The technologies
implemented in the
preferred embodiment allow a higher current rated (higher amperage) cable
assembly to future
proof the design for any DC fast charge requirements.
The preferred embodiment provides a ruggedized and robust SAE J1772 overmolded
connector assembly incorporating dielectric and environmental potting
compounds, with an
integrated polymeric substrate and overmolded polymeric skin offering
protection from extreme
and harsh environmental conditions. The preferred embodiment combines an
overmolded
integrated polymeric (laminated) approach and an integrated PC board with
micro-switch and
provisions for LED lights for a charge indicator and a flashlight. The
solution offers reduced
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life-cycle costs, improved product reliability, and a reduced risk of
tampering and vandalism
associated with mechanical locking features and hardware (such as TomTm
screws). This over-
molded solution offers exceptional environmental protection from the extreme
environmental
elements which may include: water, ice, dust, ultra-violet rays, oils and
automotive fluids.
The preferred embodiment, or any other embodiment, can be modified to
accommodate both
AC charging and rapid DC charging and to allow the user to select which
charging mode will be
used. Figure 22A shows a head-on view of a connector 2200 thus modified,
Figure 22B shows a
cross-sectional view of the connector, taken along lines XXIIA-XXIIA in Figure
22A. Figures
22C and 22D show side and top views, respectively. The connector 2200 is
constructed and used
like the connector 100 previously disclosed, except that in addition to the
connector front piece
102 and pins 104-112, the connector 2200 also has two additional pins 2202,
2204 connected to
leads 2206 and enclosed in a second connector front piece 2208. Any suitable
switch can be
provided to allow the user to select between AC charging and rapid DC
charging.
While a preferred embodiment has been set forth above, those skilled in the
art who have
reviewed the present disclosure will readily appreciate that other embodiments
can be realized
within the scope of the invention. For example, any suitable latching
mechanism can be used, as
can any suitable materials. Also, the connector can be adapted to any standard
or proprietary
layout. Therefore, the present invention should be construed as limited only
by the appended
claims.
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