U.S. patent application number 11/699695 was filed with the patent office on 2007-05-31 for battery venting system.
This patent application is currently assigned to Eastway Fair Company, Limited. Invention is credited to Xiao Ping Liu, Roger Q. Smith.
Application Number | 20070122692 11/699695 |
Document ID | / |
Family ID | 33159530 |
Filed Date | 2007-05-31 |
United States Patent
Application |
20070122692 |
Kind Code |
A1 |
Smith; Roger Q. ; et
al. |
May 31, 2007 |
Battery venting system
Abstract
A battery venting system that is useful for cordless power
tools. The system can include a cell that may have a sleeve with a
plurality of apertures surrounding a peripheral side face of the
cell to enhance heat dissipation from the cell. A plurality of
cells may be electrically connected to form a cell pack. A carrier
includes an upper carrier and a lower carrier to sandwich a
plurality of cells that are aligned parallel to each other. The
carriers include at least one vent hole that are aligned with a gap
formed from adjacent cells to define an elongated fluid flow path.
A charger may be provided to receive a housing containing the
carrier and may be provided with a fan to direct a flow into the
fluid flow path.
Inventors: |
Smith; Roger Q.; (Hong Kong,
HK) ; Liu; Xiao Ping; (Nan Chang City, CN) |
Correspondence
Address: |
BRINKS HOFER GILSON & LIONE
P.O. BOX 10395
CHICAGO
IL
60610
US
|
Assignee: |
Eastway Fair Company,
Limited
|
Family ID: |
33159530 |
Appl. No.: |
11/699695 |
Filed: |
January 30, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10453836 |
Jun 3, 2003 |
7189473 |
|
|
11699695 |
Jan 30, 2007 |
|
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Current U.S.
Class: |
429/87 ; 320/107;
429/148; 429/152 |
Current CPC
Class: |
H01M 50/107 20210101;
H01M 10/643 20150401; H01M 10/6563 20150401; H01M 10/613 20150401;
H01M 50/10 20210101; H01M 10/6551 20150401; H01M 10/46 20130101;
H01M 6/42 20130101; H01M 10/6235 20150401; H01M 10/653 20150401;
H01M 10/6557 20150401; Y02E 60/10 20130101; H01M 10/6566
20150401 |
Class at
Publication: |
429/087 ;
429/152; 320/107; 429/148 |
International
Class: |
H01M 2/12 20060101
H01M002/12; H02J 7/00 20060101 H02J007/00 |
Claims
1-22. (canceled)
23. A battery venting system comprising: a. a charger including a
first surface for electrically coupling with at least two
chargeable battery packs; b. a first outlet provided on the first
surface and located adjacent at least a portion of a vent system of
a battery pack; c. a second outlet provided on the first surface
and located adjacent at least a portion of a vent system of another
battery pack; d. a mechanism in the charger for simultaneously
moving fluid through the vent system of the at least two battery
packs.
24. The battery venting system of claim 23 wherein the mechanism in
the charger includes a fan.
25. The battery venting system of claim 24 wherein the mechanism in
the charger includes a duct to fluidically connect an output of the
fan with each of the outlets.
26. The battery venting system of claim 25 wherein the duct
includes a central portion with a first arm and a second arm
extending from the central portion.
27. The battery venting system of claim 26 wherein the duct is
substantially T-shaped.
28. The battery venting system of claim 24 wherein the fan is
modulated by a sensor.
29. The battery venting system of claim 23 wherein the housing is
removably coupled with a cordless power tool.
30. The battery venting system of claim 23 wherein the charger
sequentially charges the at least two chargeable battery packs.
31. The battery venting system of claim 23 wherein the charger
simultaneously charges the at least two chargeable battery
packs.
32. A battery charger comprising: a. a charger including a first
surface for electrically coupling with at least two chargeable
battery packs, wherein the charger simultaneously charges the at
least two chargeable battery packs; and, b. a mechanism associated
with the charger for simultaneously moving fluid through a vent
system of the at least two battery packs.
33. The battery charger of claim 32 further comprising a first
outlet provided on the first surface and located adjacent at least
a portion of the vent system of a respective one of the at least
two battery packs.
34. The battery charger of claim 33 further comprising a second
outlet provided on the first surface and located adjacent at least
a portion of the vent system of a respective another one of the at
least two battery packs.
35. A battery charger comprising a charger including a first
surface for electrically coupling with at least two rechargeable
battery packs, wherein the charger simultaneously charges the at
least two rechargeable battery packs.
36. The battery charger of claim 35 wherein the first surface
slidably receives the at least two rechargeable battery packs.
37. The battery charger of claim 35 wherein the first surface
includes at least two slots to respectively receive the at least
two rechargeable battery packs.
38. The battery charger of claim 37 wherein the at least two slots
include electrical contacts.
39. The battery charger of claim 28 wherein the sensor senses one
of a voltage of at least one cell of the battery pack or a
temperature within the battery pack.
40. The battery charger of claim 28 wherein the sensor senses a
temperature within the charger.
41. The battery charger of claim 34 further comprising an inlet to
the mechanism wherein fluid flows from the inlet through the vent
system of the at least two battery packs.
42. The battery charger of claim 41 further comprising a sensor to
control the mechanism.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to a battery venting
system that is useful for cordless power tools. The system includes
one or more of battery cells, sleeves that may surround the battery
cell, a carrier that can position and hold a number of battery
cells to form a cell pack, and a charger useful with the battery
cells and/or carrier.
[0002] Rechargeable nickel-cadmium cells and nickel-metal hydride
cells are widely used as a battery power source for portable
apparatus, such as power tools. Typically, nickel-cadmium cells or
nickel-metal hydride cells are used in the form of a cylindrical
cell that has a cylindrical shape. In the portable apparatus, the
cylindrical cells are used alone or more typically in the form of a
cell pack in which a plurality of cells are connected and are
contained within a housing that can be removably attached to an
apparatus.
[0003] FIG. 1 shows a typical cylindrical cell, which has a
cylindrical case 1 that contains the cell materials in a closed
fashion by a cover 11. A conductive projection 11a is formed in the
cover 11, and a safety valve for releasing gasses is disposed in
the projection 11a. Generally, the cover 11 having the projection
11a the positive electrode and the case 12 is the negative
electrode. A sleeve 13 usually surrounds the peripheral side of the
cell and is formed from an electrically insulating material so that
when the battery cells are intentionally or unintentionally
touching each other at the peripheral side face, the battery cells
will not short out or discharge.
[0004] When the cylindrical cell 1 is to be used as a power source
for an apparatus, a plurality of cells are connected to each other
to form a cell pack, as shown in FIG. 2. Adjacent cells 1 are
bridged by an electrically conductive plate 9, such as a nickel
plate. The plate may be attached by spot-welding or other methods
of attaching to the projection 11a of the cover 11 of one of the
cells and the bottom face of the case 12 of the other cell,
respectively. To further secure and position the plurality of
cells, it is known to wrap the periphery of the outermost cells
with a shrinkable plastic or tape.
[0005] A disadvantage to providing an electrically insulating case
around each cell is that when a plurality of cells are provided to
form a cell pack, heat generated upon discharge and upon recharging
operations is not easily dissipated. Likewise, when a cell pack is
wrapped with shrinkable plastic or tape, the generated heat is
further hindered from dissipation. When the temperature of the cell
is raised as a result of the heat generation, self-discharge may
reduce the cell capacity or shorten the service life of the cell.
This problem is also applicable to sealed-type cells or other types
such as rectangular cells.
[0006] Accordingly, there have been attempts to address this issue
by providing cell holders such as that shown in U.S. Pat. No.
5,578,392, particularly FIG. 13. There, a cell holder is provided
to hold and position individual battery cells. In this cell holder,
an upper and a lower plate is provided to respectively receive the
upper and lower portion of the individual cells. Each plate has a
plurality of spaced apart cell holes into which a portion of the
upper or lower portion of a battery cell can be received.
Accordingly, a gap is formed between adjacent cells to facilitate
heat dissipation during discharge and charging operations. Although
this solution may be useful, the plates take up space within the
battery pack housing and by virtue of their size still hinder heat
dissipation.
BRIEF SUMMARY OF THE INVENTION
[0007] With the above in mind, in one aspect of the present
invention, a battery cell having a first terminal and a second
terminal is provided without an outer case or covering. In one
embodiment, the battery cell may be cylindrically shaped with a
first end having a first terminal and a second end spaced from the
first end and having a second terminal. A longitudinal axis extends
from the first end to the second end. A peripheral side face is
disposed between the first end and the second end.
[0008] In another aspect of the present invention, a battery cell
is provided with a sleeve to surround the peripheral side face of
the cell. The sleeve is formed from an electrically insulating
material and has a plurality of apertures. The sleeve may be formed
form paper, plastic, or any other suitable electrical insulating
material. The sleeve may also be formed of a plastic mesh such as a
molded plastic mesh.
[0009] The apertures may have a variety of suitable shapes such
that the peripheral side face of the cell is sufficiently exposed
to allow heat to dissipate while still allowing the cell to be
insulated when contacted by a similar cell having a sleeve.
Suitable aperture shapes include those selected from a circle,
ellipse, parabola, crescent, obround, disc, triangle, rectangle,
polygon, and mixtures thereof. Where the aperture has a shape that
provides a longer side (or a pair of longer sides) and a short side
(or a pair of shorter sides, like an obround, the longer side(s)
may be arranged to be parallel to the longitudinal axis.
Alternatively, the longer side(s) may be arranged to be normal to
the longitudinal axis.
[0010] In yet another aspect of the present invention, a carrier of
a plurality of battery cells is provided to arrange and hold the
plurality of battery cells to define a cell pack. The carrier may
be used with battery cells without an outer case, with battery
cells having an outer case, or with battery cells having
electrically non-conductive sleeves according to the present
invention. In one embodiment, the carrier causes the terminals on
each end of the cells to be positioned in a substantially same
plane.
[0011] In this cell pack, a plurality of cells are arranged
side-by-side and are generally parallel to their longitudinal axis.
An electrically conductive connecting member connects the cells
with each other. The electrically conductive material may be
configured of a flexible material. Even when vibration or shock is
applied to the cell pack, therefore, the force acting between the
cylindrical cells is absorbed by the flexible material of the
connecting member.
[0012] It is a still further object of the invention to provide a
cell carrier in which upper and lower end portions of sealed-type
cells are held by a respective upper carrier and lower carrier to
define a vent space between adjacent battery cells, thereby
allowing heat generated from the sealed-type cells to be dissipated
to the exterior via the vent hole. The upper carrier and lower cell
carrier are provided with apertures that are aligned with the vent
space to define an elongated fluid flow path to allow heat to be
dissipated. The upper carrier and lower carrier are also provided
with a connecting member receiving area.
[0013] According to the present invention, a plurality of battery
cells are held between the pair of upper and lower carriers and
heat generated from the cells can be dissipated via the elongated
fluid flow path. Since the outward-directed peripheral side faces
of the battery cells may be free of electrically insulating
material and are exposed to the exterior between the pair of upper
and lower carriers, heat can also be dissipated from the peripheral
side faces of each battery cell. Alternatively, if a sleeve
according to the present invention is provided, i.e., with a
plurality of apertures, a substantial portion the peripheral side
faces of the battery cells will be exposed to the exterior between
the pair of upper and lower carriers so that heat can be dissipated
from the peripheral side faces of each battery cell.
[0014] The venting effect can be further enhanced by forcing a
fluid such as air past and through the cell pack. For example, in
another aspect of the present invention, a charger is provided with
a fan to force a fluid into the cell pack where it can pass through
adjacent cells. Advantageously, the charger may be configured to
provide charging of more than a single cell pack, either
sequentially or simultaneously. The charger is provided with a
mechanism to simultaneously force fluid into two separate cell,
while charging.
[0015] The cell pack may be provided with contacts that operatively
associated with the cell pack to act as a conduit to transfer
electricity to the motor of a power tool or to receive a charge
from a charger. In addition, the cell pack may be provided with an
outer casing or housing, typically formed of plastic to define a
battery pack.
[0016] Additional aspects, objects, and advantages of the invention
will become apparent from the detailed description, the appended
claims, and accompanying drawings, as well as by practice of the
invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The accompanying drawings illustrate an embodiment of the
invention and together with the description serve to explain the
principles of the invention. In the drawings, the same reference
numerals indicate the same parts.
[0018] FIG. 1 is a perspective view of a prior art cylindrical
battery cell.
[0019] FIG. 2 is a perspective view of a plurality of cylindrical
battery cells electrically connected to define a cell pack.
[0020] FIG. 3 is a perspective view of a plurality of cylindrical
battery cells having sleeves according to the present invention and
being electrically connected to define a cell pack.
[0021] FIG. 4 is a perspective exploded view of a carrier for a
plurality of cylindrical battery cells electrically connected to
define a cell pack.
[0022] FIG. 5 is a perspective view of a carrier for a plurality of
cylindrical battery cells electrically connected to define a cell
pack.
[0023] FIG. 6 is a perspective view of a battery charger useful for
simultaneously charging two batteries and containing a venting
system according to one aspect of the present invention.
[0024] FIG. 7 is a rear cut-away view of the charger with elements
removed to better illustrate the venting system of the present
invention. One embodiment of the duct that forms a portion of the
venting system is shown with a portion removed to better illustrate
the flow of fluid through the duct and to a battery pack that
houses the carrier of the present invention. A portion of the
battery pack housings are cut-away to show the carrier. In
addition, the battery pack housings are is shown just before
engagement with the charger.
[0025] FIG. 8 is a bottom view of a portion of a venting system for
a battery charger according to one aspect of the present
invention.
[0026] FIG. 9 is a bottom view of one embodiment of a duct that
forms a portion of the venting system useful in a battery charger
that is capable of receiving two battery packs.
[0027] FIG. 10 is a bottom view of a battery charger that is
capable of receiving two battery packs and the duct of FIG. 9 that
forms a portion of the venting system. Certain parts of the battery
charger and venting system are not shown to better illustrate the
duct.
DETAILED DESCRIPTION OF THE INVENTION
[0028] Referring now to the drawings and initially to FIG. 1, a
prior art battery cell is shown. The prior art battery cell 1 has a
cylindrical case that contains the cell materials in a closed
fashion by a cover 11. A conductive projection 11a is formed in the
cover 11, and a safety valve for releasing gasses is disposed in
the projection 11a. Generally, the cover 11 having the projection
11a is the positive electrode and the case 12 is the negative
electrode. Generally, an outer sleeve 13 is formed from an
electrically insulating material so that when the battery cells are
intentionally or unintentionally touching each other at the
peripheral side face, the battery cells will not discharge.
[0029] When the prior art cylindrical cell 1 is to be used as a
power source for an apparatus, generally, a plurality of cells are
connected to each other to form a cell pack, as shown in FIG. 2.
Two adjacent cells 1 are bridged by an electrically conductive
plate 9, such as a nickel plate. The plate 9 may be attached by
spot-welding or other method of attaching the plate 9 to the
projection 11a of the cover 11 of one of the cells and the bottom
face of the case 12 of the other cell, respectively. The sleeve 13
acts to prevent adjacent cells from shunting. In the description of
the embodiments of the present invention, components having the
same function as those of the prior art described above with
respect to FIG. 1 and 2 are designated by the same reference
numerals.
[0030] Turning now to FIG. 3, one embodiment of the present
invention is shown. Although the cell 1 is depicted with a
cylindrical shape, it is to be understood that the cell 1 can have
any suitable shape presently known or that can be contemplated in
the future. In general, the cell 1 has a first end 2 end and a
second end 3 spaced from the first end 2 to define a peripheral
side face 4 that extends from the first end 2 to the second end 3.
A longitudinal axis 5 extends from the first end 2 to the second
end 3 of the cell 1. The first end 2 has a cover 11 from which a
projection 11a extends. The projection 11a defines a positive
electrode or terminal. The second end 3 defines a negative
electrode or terminal. While the cell 1 may be a nickel-cadmium
cell or a nickel-metal hydride cell, the present invention is not
restricted those types of cells.
[0031] According to another embodiment of the present invention,
the cell 1 is provided with a sleeve 30 that surrounds the
peripheral side face 4 of the cell 1. The sleeve 30 made be made of
any suitable electrically insulating material. For example, the
sleeve 30 may be made from paper, plastic, or any other suitable
insulating materials. The sleeve 30 may be a molded plastic mesh or
similar construction.
[0032] Desirably, the sleeve 30 is provided with a plurality of
apertures 32 to allow heat to dissipate from the cell 1. The
apertures 32 may have any suitable shapes such that the cell 1 is
sufficiently exposed to allow heat to dissipate while still
allowing the cell 1 to be insulated when contacted by a similar
cell 1 having a sleeve 30. Suitable shapes include those selected
from a circle, ellipse, parabolic, crescent, obround, disc,
triangle, rectangular, polygonal, and mixtures thereof. Where the
aperture 32 has a shape that provides a longer side (or a pair of
longer sides) and a short side (or a pair of shorter sides, like an
obround, the longer side(s) may be arranged to be parallel to the
longitudinal axis 5. Alternatively, the longer side(s) may be
arranged to be normal to the longitudinal axis 5.
[0033] To form a cell pack 20, a plurality of individual cells 1
are electrically connected to each other. FIG. 3 shows the case
where a cell pack is configured by six cylindrical cells 1. One
skilled in the art will understand that this embodiment of the
present invention is applicable to any number of battery cells and
is applicable to any shape of battery cell. Of course, in the case
where two or more cells 1 are used, a cell pack 20 is configured by
connecting the cells 1 to each other by an electrically conductive
connecting member 9. Instead of connecting the cells 1 in series,
the cells 1 may be connected in parallel or in a combination of
series and parallel connections. Accordingly, the connecting member
9 may connect adjacent positive terminals, adjacent negative
terminals, both, or adjacent positive and negative terminals.
[0034] The electrically conductive connecting member 9 may be
formed from any suitable electrically conductive material.
Non-limiting examples include nickel, nickel and steel composites,
steel, or nonferrous conductive material. The electrically
conductive connecting member 9 may be attached by spot welding or
by any other suitable attachment method such as laser welding.
[0035] Next, with reference to FIGS. 4 and 5, an embodiment of the
carrier of the present invention in which fifteen cylindrical cells
are held will be described. In the present invention, however, the
kind and shape of the cell 1 are not restricted to nickel-cadmium
or nickel-metal hydride and conventional manganese cells or
sealed-type cells of other types such as those of rectangular cells
may be used. In addition, while the present invention will be
illustrated and described with fifteen cells, one skilled in the
art will appreciate that the carrier will be suitable for use with
any number of cells, for example, twelve, ten, seven, four, or even
two depending on the desired voltage output.
[0036] As shown in FIG. 4, the fifteen cells 1 are arranged in
three rows with each row consisting of five cells 1. The fifteen
cells 1 are sandwiched between an upper carrier 40 and a lower
carrier 50 to define a carrier 60. Desirably, the upper carrier 40
and lower carrier 50 are made of an electrically insulating
material such as a synthetic resin. The upper carrier 40 and the
lower carrier 50 have a significant portion that is substantially
flat. The thickness of the upper carrier 40 and the lower carrier
50 ranges from about 0.25 mm to about 25 mm, desirably from about
0.5 mm to about 10 mm, more desirably from about 0.75 mm to about
1.25 mm. The upper carrier 40 and lower carrier 50 are used while
being disposed opposing each other.
[0037] The upper carrier 40 has an upper surface 41 and a lower
surface 42, which faces the battery cells 1. The upper carrier 40
has a plurality of ribs 43 extending outward from the lower surface
42. The ribs 43 are located on the upper carrier 40 in certain
areas to cooperatively interact with and engage the battery cells 1
to correctly position them with respect to each other. In this
regard, the ribs 43 are spaced from each other and therefore they
do not completely surround the cell 1.
[0038] The number of ribs 43 provided will be that necessary to
selectively position the number of cells 1 forming the desired cell
pack 20. in addition, when the upper carrier 40 is placed on the
plurality of battery cells 1 the ribs 43 extend from upper carrier
40 a distance substantially less than the distance from the top 2
to the bottom 3 of the cell 1. Because the cell 1 may have any of a
variety of different shapes and heights, the length of the ribs 43
will vary depending on the shape of the cell 1. Desirably, the ribs
43 extend a distance less than one-half the distance from the top 2
to the bottom 3 of the cell 1. For example, the ribs 43 extend from
the lower surface 42 a distance ranging from about 0.5 mm to about
10 mm, desirably from about 3 mm to about 6 mm.
[0039] The upper carrier 40 is provided with shaped cut-outs 44
that substantially conform to the shape of the electrically
conductive connecting member 9. Thus, when the connecting member 9
is rectangular, the cut-out 44 will likewise have a rectangular
shape with dimensions substantially the same (slightly larger) as
the dimensions of the connecting member 9. The thickness of the
upper carrier 40 may be substantially the same as the thickness of
the connecting member 9 so that when the upper carrier 40 is placed
on top of the plurality of cells 1 forming the cell pack 20, the
upper surface of the connecting member 9 and the top surface 41 of
the upper carrier 40 will lie in substantially the same plane.
Alternatively, the connecting member 9 can have a thickness
slightly less than the thickness of the upper carrier 40 so that
the connecting member 9 does not extend beyond the top surface 41
of the upper carrier 40.
[0040] The upper carrier 40 is also provided with a plurality of
vent openings 46. In general, the vent openings 46 are provided on
the upper carrier 40 at a location that is aligned with a gap 6
formed by adjacent cells 1. For example, referring to FIG. 4, a gap
6 is formed by three adjacent cells 1. By providing vent openings
46 on the upper carrier 40, fluid flowing through the gap 6 can
also flow through the vent openings 46 to more effectively
dissipate heat generated by the cells 1.
[0041] The lower carrier 50 has a lower surface 51 and an upper
surface 52, which faces the battery cells 1. The lower carrier 50
has a plurality of ribs 53 extending outward from the upper surface
52. The ribs 53 are located on the upper carrier 50 in certain
areas to cooperatively interact with and engage the battery cells 1
to correctly position them with respect to each other. In this
regard, the ribs 43 are spaced from each other and therefore they
do not completely surround the cell 1. In addition, the ribs 53 are
also located in areas on the lower carrier 50 so that when the
upper carrier 40 and the lower carrier 50 are placed on the cells 1
to effectively sandwich the cells 1, the cells 1 will be aligned
substantially vertically and parallel to each other, i.e., parallel
to the longitudinal axis 5.
[0042] The number of ribs 53 provided will be that necessary to
selectively position the number of cells 1 forming the desired cell
pack 20. When the lower carrier 50 is placed on the plurality of
battery cells 1 the ribs 53 extend from lower carrier 40 a distance
substantially less than the distance from the bottom 3 to the top 2
of the cell 1. Because the cell 1 may have any of a variety of
different shapes and heights, the length of the ribs 53 will vary
depending on the shape of the cell 1. Desirably, the ribs 53 extend
a distance less than one-half the distance from the bottom 3 to the
top 2 of the cell 1. For example, the ribs 53 extend from the upper
surface 52 a distance ranging from about 0.5 mm to about 10 mm,
desirably from about 3 mm to about 6 mm.
[0043] The lower carrier 50 is provided with shaped cut-outs 54
that substantially conform to the shape of the electrically
conductive connecting member 9. Thus, when the connecting member 9
is rectangular, the cut-out 54 will likewise have a rectangular
shape with dimensions substantially the same (slightly larger) as
the dimensions of the connecting member 9. The thickness of the
lower carrier 50 may be substantially the same as the thickness of
the connecting member 9 so that when the lower carrier 50 is placed
on the plurality of cells 1 forming the cell pack 20, the exposed
surface of the connecting member 9 and the lower surface 51 of the
lower carrier 50 will lie in substantially the same plane.
Alternatively, the connecting member 9 can have a thickness
slightly less than the thickness of the lower carrier 50 so that
the connecting member 9 does not extend beyond the lower surface 51
of the lower carrier 50.
[0044] The lower carrier 50 is also provided with a plurality of
vent openings 56. In general, the vent openings 56 are provided on
the lower carrier 50 at a location that is aligned with a gap 6
formed by adjacent cells 1. For example, referring to FIG. 4, a gap
6 is formed by three adjacent cells 1. In addition, the vent
openings 56 provided on the lower carrier 50 are aligned with the
vent openings 46 provided on the upper carrier 40. By aligning the
vent openings 46, 56 and the gap 6, fluid flowing through the gap 6
can also flow through the vent openings 46, 56 to more effectively
dissipate heat generated by the cells 1.
[0045] As shown in FIG. 5, the carrier 60 causes the cells 1 to be
positioned in such a manner that the end portions 2 and 3 are in
the substantially same plane. In this case, the electrically
conductive connecting member 9 is not required to be bent and can
be made flat so that the terminals are easily connected to each
other.
[0046] In addition, In the cell pack shown in FIG. 5, in which the
cylindrical cells 1 are held by the carrier 60, as described above,
ventilation is enabled between the exterior and the vicinity of the
inward-directed peripheral side faces of the cylindrical cells 1,
via the vent openings 46, 56 provided in the upper carrier 40 and
lower carrier 50, respectively, which as noted above are
longitudinally aligned. Consequently, heat generated from the
cylindrical cells 1 can be rapidly dissipated to the exterior and
the temperature rise of the cylindrical cells 1 is reduced so that
it does not exceed the specified range.
[0047] It is believed that the cells 1 closest to the center of the
cell pack 20 tend to cool slower than those cells farthest from the
center of the pack. Therefore, the size of the vent openings 46, 56
can be varied so that the vent openings 46, 56 closest to the
center of the cell pack 20 are larger than the vent openings
farthest from the center of the cell pack 20.
[0048] The ventilation due to the vent openings 46, 56 and the like
can occur as a result of natural convection. When the amount of
generated heat is expected to be large or is large, the natural
convection can be enhanced by providing a fluid moving device to
force a fluid around the outward directed peripheral side face 4 of
the cells 1 and through the vent openings 46, 56 provided in the
upper carrier 40 and lower carrier 50.
[0049] The carrier 60 of the present invention may be used with
cells 1 that are bare or do not have any insulating cover. In this
instance, the ribs 43, 53 are located on the upper carrier 40 and
lower carrier 50, respectively so that adjacent cells 1 do not
touch. As a result, effective heat dissipation can occur.
Alternatively, the carrier 60 of the present invention may be used
with cells 1 that are provided with sleeves 30 according to the
present invention or with standard known cells.
[0050] A filter (not shown) may be placed adjacent each of the
upper carrier 40 and lower carrier 50 to reduce or prevent dust
entering the cell pack 20. The filter may be any suitable material
such as a synthetic fiber mesh.
[0051] The cell pack may also have a temperature indicating device
to indicate the temperature of one or more cells 1 in the cell pack
20. The temperature indicating device may be thermistor, a
capacitor, a theromostat, or other temperature indicating
device.
[0052] One skilled in the art will understand that the cell pack of
the present invention can be provided with one or more electrical
contacts that operatively associated with the cell pack 20. The
electrical contacts act as a conduit of electricity from the cell
pack 20 to the motor of a power tool with which the cell pack 20 is
associated. In addition, the electrical contacts act to transfer
the charge from a charger so that the cells in the cell pack 20 can
be recharged.
[0053] In addition, it is customary to provide a housing 100 that
surrounds the cells 1 and cell pack 20 to define a battery pack
102. In this regard, FIG. 6 shows a battery charger 200
incorporating a venting system 220 and having two battery packs 102
operatively associated with the charger 200. The housing 100 may be
formed from any suitable material but is typically formed of a hard
plastic to aid in protecting the cells. The upper 110 and lower 120
faces of the battery pack 102 may contain vents 112, 122 to allow
fluid to pass through the housing 100 and the vents 46, 56 provided
on the upper carrier 40 and the lower carrier 50. Although it is
understood that the upper 110 and lower 120 faces of the battery
pack 102 are relative, for ease of description, the upper face 110
of the battery pack 102 will be considered to be that face adjacent
the upper carrier 40 and the lower face 120 of the battery pack 102
will be considered to be that face adjacent the lower carrier 50.
The battery pack 102 may be slideably engaged with a power tool
such that the battery pack 102 can be removed from the power tool
and placed in a charger 200 for recharging the cells 1.
[0054] The charger 200 includes a housing having one surface that
receives a battery pack. For convenience the charger 200 will be
described as having a top 202, a bottom 204, and at least one side
208. It will be understood, however, that the configuration of the
charger 200 is not particularly important so long as the features
described below are incorporated. In addition, for convenience, the
one surface will be referred to as the top surface 202. The top
surface 202 is provided with at least one slot 210 to removably
receive a battery pack. In a desired embodiment, the charger 200 is
provided with two slots 210a, 210b to simultaneously receive two
separate battery packs 102. Each slot 210 has respective contacts
to couple with the electrical contacts 70 associated with the cell
pack 20 to charge the cells 1. The charging of the cells 1 may be
controlled by a switch, a microcontroller, a circuit or the like.
Methods of designing and operating the charging mechanism are known
and any of several different operating schemes may be used.
[0055] The charger 200 further includes a venting system 220 that
includes an inlet 222, an outlet 224, a fan 226, and a duct 230 to
direct fluid from the fan 226 to the outlet 224. The outlet 224 is
associated with vents 122 provided on the lower face 120 of the
battery housing 100 so that fluid flows from the fan 226, through
the duct 230, into the battery housing 100 and through the vents 56
in the lower carrier 50, across the cells 1 and out the vents 46 in
the upper carrier 40 and the vents 112 in the upper face 110 of the
battery housing 100. Alternatively, the fan 226 may be arranged to
suck fluid from the outlet 224 to the inlet 222 so that the fluid
is moved from the vents 112 on the battery housing 100 through the
vents 46 in the upper carrier 40, across the cells 1 through the
vents 56 in the lower carrier 50 and into the duct 230. It will be
understood by one skilled in the art the terms inlet and outlet are
relative to the direction of the fan flow. For ease description,
the fan flow will be described as moving fluid from the charger
housing 200 into the battery housing 100. Accordingly, the outlet
224 of the charger housing 200 will be disposed on the top 202 of
the charger housing 200 and will be associated with the vents 122
provided on the lower face 120 of the battery housing 100.
[0056] As noted above, the venting system 220 includes an inlet 222
that may be provided on the top 202 of the charger housing 200, the
bottom 206 of the charger housing 200, the side(s) 208 of the
charger housing 200 or each of them. The inlet 222 may be provided
by a grill, slots, or other types of openings such that fluid,
typically air, can pass into the charger housing 200 to the fan
226. A filter may be provided adjacent the inlet to reduce or
prevent particles such as dust from entering the charger housing
200.
[0057] The outlet 224 is provided on the top 202 of the charger
housing 200 such that when a battery pack 102 is positioned on the
charger 200, the outlet 224 is aligned with the vents 122 provided
on lower face 120 of the battery pack 102 so that fluid may enter
the battery pack 102. For example, the top 202 of the charger 200
has a slot 210 to receive the battery pack 102. The outlet 224 may
be provided within the confines of the slot 210 or adjacent to the
slot 210 so long as the outlet 224 is adjacent the vents 122
provided on the lower face 120 of the battery pack 102.
[0058] In the desired embodiment, the charger 200 is provided with
two slots 210a and 210b so that two battery packs 102 may be
simultaneously located on the charger 200. In this instance, at
least one outlet 224a and 224b will be respectively associated with
each slot 210a and 210b. A screen or grill may be located adjacent
the outlet 224 to reduce or prevent dust, chips, or other things
from entering the battery pack 102.
[0059] A duct 230 fluidically connects the fan 226 to the outlet
224. The duct 230 has a bottom wall 232 with a side wall 234
extending from the periphery of the bottom wall 232. The bottom
wall 232 is provided with a central portion 236 having a first arm
240 and a second arm 244 connected with and extending from the
central portion 236. The duct 230 is desirably formed with smooth
contours to minimize flow and pressure gradients. The bottom 232
may be T-shaped, Y-shaped, or shaped in a similar fashion such that
fluid can flow from a central portion 236 to the first 240 and
second 244 arms. The bottom wall 232 has an aperture 238 to receive
the fan 226. Desirably, the aperture 238 is provided in the central
portion 236 so that fluid is distributed about equally to each of
the first arm 240 and second arm 244 of the duct 230.
[0060] The first arm 240 terminates at a terminal end 242 and the
second arm 244 terminates at a terminal end 246 with the terminal
ends 242, 246 located adjacent respective outlets 224a, 224b. A
seal may be provided between the terminal end of the arms 242, 246
and the outlet 224 to reduce or prevent fluid from by passing the
outlet 224.
[0061] The duct 230 is desirably located within the charger housing
200 such that the underside 204 of the top 202 of the charger
housing 200 forms a top surface of the duct 230. In this way, the
duct 230 will be closed except for the portion that is adjacent to
the outlet 224. Alternatively, the duct 230 can be provided with a
top housing (not shown) to enclose the side wall 234 except at the
terminal end of the arms 242, 246. It will be appreciated that when
the fan 226 is activated, fluid is directed from the fan inlet,
into the duct 236 and through the terminal ends of the arms 242,
246 to the respective outlet 224a, 224b and through the vents 122
on the lower face 120 of the battery housing 100.
[0062] The fan 226 can be activated as desired. For example, the
charger electronics could be coupled with a sensor inside the
battery pack 102 that would be activated through the electrical
contacts. The sensor could sense a property of the cell pack 20
such as voltage of one or more cells 1, temperature within the cell
pack 20, or other property. Based on the output of the sensor, the
fan 226 could be activated to run. Alternatively, the fan 226 could
be activated to continuously be activated while the charger is
operating. The fan 226 could also be activated through the use of a
manual switch provided on the charger housing 200.
[0063] In yet another alternative, a mechanical switch may be
provided such that when a battery pack 102 is positioned within a
slot 210 of the charger housing 200, the fan 226 can be activated.
In this embodiment, when the battery pack 102 is removed from the
slot 210, the fan 226 will be de-energized.
[0064] Other fan modulation process may also be used. For example,
the fan 226 may be turned on for a predetermined period and turned
off before a battery pack 102 is disposed on the charger 200. This
period could occur when the charger 300 is either turned on,
connected to an electrical outlet or when a button on the charger
200 is pushed. This would blow foreign particles, such as dust,
that has settled on the charger 200 and or the slot 210.
Accordingly, the particles or dust would not be blown into the
battery pack 102 during charging. This result can also be achieved
if the fan 226 is always on, on after the battery pack 102 has been
removed, or if the fan 226 is periodically turned on and off when
the battery pack 226 is not disposed in the charger 200.
[0065] In addition, rather than fan 226 being completely turned
off, it may be expedient to just regulate the power sent to the fan
226 so that the fan 226 rotates at a lower speed. Accordingly, the
fan 226 can rotate at a first speed before the battery pack 102 is
disposed on the charger 200. When the battery pack 102 is disposed
on the charger 200, the fan 226 can rotate at a second speed, which
is higher than the first speed. When the battery pack 102 is
removed, the fan 226 can be turned off completely or brought back
to a lower speed. This would also help in maintaining the duct 230
free of dust.
[0066] It may be desirable to turn the fan 226 on at a high first
speed for a predetermined period and then lower the speed before a
battery pack 102 is disposed on the charger 200. This period could
occur when the charger 200 is either turned on, connected to an
electrical outlet or when a button on the charger 200 is
pushed.
[0067] Furthermore, the charger 200 can control the speed of the
fan 226 by using information from the temperature indicating
device. For example, the charger 200 would receive information from
the temperature indicating device. If the battery pack 102 is below
a first desired temperature, the charger 200 would lower the speed
or stop the fan 226. Similarly, the charger 200 can control the fan
226 to maintain the temperature of battery pack 102 near a
predetermined temperature.
[0068] In addition, the charger 200 can control the fan 226 to
obtain accurate information from the temperature indicating device.
For example, if the temperature indicating device was exposed to
the air or fluid flow, the temperature indicating device might
indicate a cell temperature lower than the actual cell temperature.
Such result can be minimized or avoided if the charger 200
periodically lowers the speed of or stops the fan 226 for a
predetermined period of time. This would allow the temperature
indicating device to indicate or show a more accurate cell
temperature, which can then be read by the charger 200 and used in
its temperature analysis. The charger 200 can then increase the
speed of or start the fan 226 until the next time the charger 200
needs temperature information.
[0069] While the invention has been described in conjunction with
specific embodiments it is to be understood that many alternatives,
modifications, and variations will be apparent to those skilled in
the art in light of the foregoing detailed description. It is
therefore intended that the foregoing description be regarded as
illustrative rather than limiting, and that it be understood that
it is the following claims, including all equivalents, that are
intended to define the spirit and scope of this invention.
* * * * *