Note: Descriptions are shown in the official language in which they were submitted.
BATTERY PACK AND METHOD OF FORMING SAME
Field of the Invention
This invention relates generally to battery cell packs,
and more specifically to battery pack construction.
1 0 Background
Battery packs for portable devices such as two-way
radios typically comprise a number of cells having contacts
welded together all within a housing. The individual cells
are interconnected using sheet metal tabs which are spot
welded to the cell terminals. Usually, the interconnected
cells are then spot welded to a flex circuit and subsequently
inserted into a battery housing. This method of
manufacture is wrought with inefficient assembly
procedures and unnecessary parts and labor resulting in
excessive manufacturing expense and compromised
reliability.
Consumer loaded batteries for consumer electronics
such as cameras, radios, CD players, etc., typically have
spring loaded contacts on one end and metal contacts
coupled to the opposite end of the primary cells. Consumer
loaded battery packs do not require the extra circuitry
typically found in battery packs. Battery packs for portable
radios will usually include resistors, thermistors, diodes and
other components that enable the battery packs to be
rechargeable and/or intrinsically safe. Thus, consumer
loaded battery compartments may only have stamped metal
on the housing and electrical loss between battery cells and
circuitry is of little concern in these applications.
Other battery packs, which are either consumer
loaded or loaded and sealed by the manufacturer typically
comprise a
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number of cells that are shrink wrapped together or packaged in a
plastic housing. Again, many of these cells are t,vpically coupled
together electronically by welding steel tabs to unlike terminals
(positive and negative) on separate cells. S~bse~uently, the
welded cells are shrink wrapped together and inserted into a
housing. Again, this assembly procedure is inefficient, resulting
in excessive labor and manufacturing costs.
The drive to reduce weight in el~:tronic consumer products
is now impacting battery pack assembly as much as the drive to
increase the ease of assembly or manlJf~turability of battery
packs. Therefore, the ability to inleg.ale features in less
components and parts is critical in reducing the number of
assembling steps. Therefore, a need exists for a battery pack that
provides the convenience of consumer loaded batter,v packs,
provides for a reduction in weight, and allows for greater
efficiency and re-llJced cost in assembly and manufacture.
Rrief Descr~plion of the Dr~win~s
FIG. 1 is a perspective view of a battery pack.
FIG. 2 is a perspective view of a batter,v pack according to
a first embodiment of the present invention.
FIG. 3 is a perspective view of a batter,v pack according to
a second embodiment of the presehl invention.
FIG. 4 is a perspective view of a batter,v pack accor~ g to a
third embodiment of the present invention.
FIG. 5 is an exploded view of wall 310 taken at lines 5-5 in
FIG.4.
FIG. 6 is an exploded view of a first e,nlJod;."ent of an
attachment mechanism according to the present invention.
FIG. 7 is an exploded view of a second embodiment of an
attachment mechanism according to the present invention.
FIG. 8 is an exploded view of a third embodiment of an
attachment mechanism according to the present invention.
FIG. 9 is a perspective view of a batter,v pack according to a
fourth embodiment of the present invention.
FIG. 10 is an exploded view of an alignment mechanism
according to the present invention.
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FIG. 11 is a cross-sectional view of the baKery pack taken
at lines 11-11 of FIG. 9.
FIG. 12 is an alternate embodiment of the cross-sectional
view of FIG. 1 1.
petailed DescriDtion of the Preferred Fmbodiment
A battery pack comprises a first housing member having an
integrated latch feature, a header frame detachably mounted to
the first housing member, a plurality of cells for insertion into the
10 header frame and first housing member, circuitry on the header
for coupling the plurality of cells and providing charger and power
contacts, and a second housing member being substantially
laminar and being adhesively attached to said first housing
member.
Referring to FIG. 1, there is shown a perspective view of a
battery pack 10 discussed in US Patent No. 5,180,644 entitled
Weldless Battery Pack, issued on January 19, 1993 to Mark S. Bresin,
assigned to the present assignee. The battery pack 10 comprises a
housing having a top portion 2 and a bottom portion 4. The housing
portions are preferably constructed to snap together. Alternatively! the
housing portions could be ultrasonically welded together. The top
housing member 2 also includes a latch feature 3 that mates with a
recessed area 5 in the bottom portion 4 to allow the detachable
coupling of the battery pack 10 to a radio (not shown). Within the
housing portions 2 and 4, lies a header frame 1 1 (for holding cells 12)
being detachably mounted into at least one of the housing portions.
Referring to FIG. 2, there is shown a perspective view of a
30 battery pack 100 in accordance with the present invention. The
battery pack 100 preferably comprises a first housing member
104 having a latch feature 103 incorporated or integrated into the
first housing member 104. Next, a header frame 111 is mounted
into the first housing member 104. The header frame is
35 preferably snapped into the first housing member via the groove
150 in the header and the mating railing 152 within the housing
member 104. Alternatively, the header frame t 11 could be
WO 95/08848 2 1 ~ 812 ~ PCT/I~S94/08475
integrated as part of the first housing member 104 as well.
Another option is to ultrasonically weld the header frame 111 to
the first housing member 104. Battery cells 112 having positive
and negative terminals 114 and 113 respectively are then
oriented and inserted into the header frame 111. Circuitry means
preferably including resistors (not shown), po!yswitches (30), and
thermistors (40) are mounted on the header frame 111 to provide
charging and power contacts and the appr~p~riate circuitry for
safely charging rechargeable battery packs 8S iS known in the art.
1 0 Alternatively, the circuitry means could comprise a flex circuit
having some of the components such as the resistors,
polyswitches and thermistors, which further interconnects the
cells. Finally, a second housing member 102 is preferably
adhesively attached to the first housing member. In order to
maximize the reduction in weight, the second housing member
102 is preferably a laminar piece of plastic such as polycarbonate
having adhesive on itls interior surface for adhering to the first
housing member 104. Alternatively, the second housing member
102 could be ultrasonically welded to the first housing member
104. Additionally, the second housing member 102 could serve
as a label for the battery 100.
Referring to FIG. 3, there is shown an alternative battery
pack 200 in accordance with the present invention. The pack 200
comprises a first housing 202 preferably having snap features
204 integrally formed in the first housing. A plurality of cells 206,
pre~erably pre-packaged into a cell pack is placed and retained
within the snap features 204. The cell pack also preferably
includes a flex circuit 212 providing further interconnection
between cells, contacts and other required components such as
resistors and thermistors (not shown). Finally a second housing
member 220 is placed on top of the cell pack 206 and snaps to
the first housing member 202. The Second housing member
preferably has openings 214 for retention by the snap features
204. Additionally, openings 216 are formed in the second
housing member allowing for contact points when contacts shown
on the flex 212 are inserted within the openings 216. Likewise,
the first housing member 202 has openings 205 allowing for the
5 ~ ~ 4 ~ ~ 2 7
insertion of contact points shown on the flex 212. Optionally
further integrity can be provided to the battery pack 200 by using
double sided adhesive (208) (such as tape) between the inner
potion of the first housing and the bottom of the cell package 206
and using double sided adhesive (207) between the inner portion
of the second housing 220 and the top of the cell package 210.
Referring to FIG. 4, a third embodiment of a battery pack
according to the present invention is shown. The battery pack
generally includes a base portion or outer casing 302 adapted to
hold a battery of cells 304. It will be understood that battery 304
will include any flex strips or circuitry described in earlier
embodiment. In order to maintain battery 304 within the outer
casing 302, one or more layers of adhesive material 306 could be
used. For exa",pl~ adhesive 306 could be a glue or some form
of double sided tape. An adhesive layer 306 could be used to
attach the battery 304 to the outer case 302. Also, another
adhesive layer 306 could be employed on top of the battery to
attach an inner casing 308 to maintain battery 304 within outer
casing 302.
Generally outer casing 308 is adapted to fit over a wall
310 generally extends around the periphery of outer casing 302.
Wall 310, abutment 311 and any adhesive 306 which may be
used prevents battery 304 from shifting within outer casing 302.
Inner casing 308 is co""~osed of a molded thermoformed plastic
material or some other suitable ll,ate,ial. r,e~er~l)ly, inner casing
308 includes a label integrally formed in the thermoformed
pl~stic Wall 310 prefe,ably includes an energy di,ector 312
(shown in detail in the cross section of FIG. 5 taken at lines 5-S of
FIG. 4). Energy director 310 is employed in an ultrasonic bonding
technique. In particular a shoulder portion 314 of outer casing
308 can be ultrasonically bonded to energy director 312. The
ultrasonic bonding can be provided along the entire wall 310 or at
selected portions as needed. Any ultrasonic bonding mechanism
which is well known in the art could be used.
Also an attachment mechanism includes a plurality of tab
portions 316 positioned around the base of wall 310 to attach
inner casing 308 to outer casing 302. Corresponding receiving
W 0 95t08848 812 ~ PCT~US94tO847S
portions 318 along a foot 320 are included in outer casing 308. A
variety of embodiments for latch 316/receiving portion 320 are
described in detail in reference to FlGs. 6-8. Finally, an adhesive
material can be positioned around foot 310 to attach inner casing
308 to outer casing 302. Any one or any combination of the
adhesive bonding, ultrasonic bonding and lat~rhg can be used.
Referring to FIG. 6, an exploded view o~f a first embodiment
of an attachment mechanism is shown. The-attachment
mechanism includes a tab 322 which is generally inserted into a
dimple 324. The attachment mechanism of FIG. 6 could be used,
for example, to maintain the position of inner casing 308 relative
to outer casing 302 when ultrasonic bonding.
Referring to ~IG. 7, an exploded view of a second
embodiment of an attachment mechanism is shown. The
attachment mechanism includes a tab portion 326 adapted to
retain a notch 328 of outer casing 308. The attachment
mechanism of FIG. 6 could also be used to maintain the position
of inner casing 308 relative to outer casing 302 when ultrasonic
bonding.
Finally, referring to FIG. 8, an exploded view of a third
embodiment of an attachment mechanism is shown. The
attachment mechanism includes a latch 330 adapted to positively
engage a hole 332 positioned within the foot 318 of the outer
casing 308. In particular, latch 330 includes two portions which
can be compressed to engage hole 330. However, it will be
understood that other types of latching mechanisms commonly
known within the art could be used to positively engage the upper
casing.
Turning now to FIG. 9, a perspective view of a battery pack
according to a fourth embodiment of the battery pack is shown.
The battery pack generally includes an outer casing 402 adapted
to hold a battery of cells 404. In order to maintain battery 404
within the outer casing 402, an adhesive material 406 could be
used on either side of the battery. For example, adhesive 406
could be a glue or some form of double sided tape. Finally, an
inner casing 408 is included to maintain battery 404 within outer
casing 402.
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Unlike the embodiment of FIG. 4, the embodiment of FIG. 9
does not include a wall 310 to retain the battery from shifting
within the outer casing and to provide an energy director to
enable ultrasonic binding to the shoulder of the outer casing.
5 Rather, an energy director 410 is provided along the surface of
outer casing 402 to provide ultra sonic bonding to foot 412 of
outer casing 408. The ultrasonic bonding can be provided along
the entire energy director 410 or at selected portions.
Outer casing 402 can optionally include an alignment tab
1 0 414 to enable proper positioning of inner casing 408 relative to
outer casing 402 during ullrasonic bonding. The alignment
mechanism is shown in detail in FIG.10. Foot 412 includes a
notch 415 adapted to receive a tab 414. Flnally, positioning
guides 416 can also be selectively positioned to aid the
15 manufacture of the battery. The alignment mechanisms 416 are
shown in detail in the cross sections of FlGs.11 and 12 taken at
lines 11-11 of FIG. 9 .
Turning now to FIG.11, a cross sectional view taken at
lines B-B of FIG. 9 shows the alignment of the inner casing 408
20 with outer casing 402 and the ulll~sonic bonding at energy
di~ector 410. In particular, positioning guide 416 provides a
re~erence point for inner casing 408. Additionally, an
embankment 418 can be inclu~ed to prevent the movement of
foot 412 of inner casing 408 during ultrasonic bonding. That is,
25 bec~se the energy director is positioned along an inclined
portion of outer casing 402, foot 412, which is norrnally horizontal,
is forced into an inclined position during the ultrasonic bonding.
Accwdingly, e"lbankl"ent 418 prevents the movement of foot 412
away from positioning guide 416. Although foot 412 is shown
30 positioned at a particular location along the outer casing 402, it
will be understood that energy director 410 be positioned at any
location along wall 410.
Tuming to FIG. 12, an alternate embodiment incorporates a
leveling surface 420 including the energy director 410. Leveling
35 surface 420 prevents foot 412 from being forced to an inclined
position during ultrasonic bonding.
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WO95/08848 PCT/US94/08475
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In summary, the present invention reduces the complexity
for manufacturing and the weight of the completed battery. In
particular, a combination of ultrasonic bonding and adhesive
bonding can reduce the weight and complexity of the device. A
5 wall can contain the battery. An energy director positioned at the
top of the wall to contain the cells of a battery can provide a
region for ultrasonic bonding. An inner case can be positioned
over the wall to seal the battery. A shoulder of the inner casing
can be ultrasonically bonded to the energy director at the top of
10 the wall. Alternatively, the wall can be replaced with an energy
director positioned on the outer casing wherein a foot of the inner
casing is ultrasonically bonded to the energy director.
Accordingly, the present invention reduces complexity and cost
compared to prior art devices.
