U.S. patent application number 12/317805 was filed with the patent office on 2010-07-01 for system for reducing thermal transfer between cells in a battery.
This patent application is currently assigned to Gateway Inc.. Invention is credited to Michael R. Flannery.
Application Number | 20100167108 12/317805 |
Document ID | / |
Family ID | 42285342 |
Filed Date | 2010-07-01 |
United States Patent
Application |
20100167108 |
Kind Code |
A1 |
Flannery; Michael R. |
July 1, 2010 |
System for reducing thermal transfer between cells in a battery
Abstract
A thermal transfer barrier is disclosed that is positionable
adjacent to an electrical storage cell having a vent configured to
release gasses from the cell. The thermal transfer barrier may
comprise a barrier member having a first side for orienting toward
the vent on the cell. The first side is contoured in a manner
configured to collect gas directed toward the first side of the
barrier member from the vent when released from the vent and guide
the collected gas away from a cell positioned adjacent to the
cell.
Inventors: |
Flannery; Michael R.; (Sioux
City, IA) |
Correspondence
Address: |
GATEWAY, INC.;ATTN: Patent Attorney
610 GATEWAY DRIVE, MAIL DROP Y-04
N. SIOUX CITY
SD
57049
US
|
Assignee: |
Gateway Inc.
|
Family ID: |
42285342 |
Appl. No.: |
12/317805 |
Filed: |
December 30, 2008 |
Current U.S.
Class: |
429/82 ;
429/149 |
Current CPC
Class: |
H01M 50/308 20210101;
H01M 2200/00 20130101; H01M 50/502 20210101; H01M 50/213 20210101;
Y02E 60/10 20130101 |
Class at
Publication: |
429/82 ;
429/149 |
International
Class: |
H01M 6/02 20060101
H01M006/02; H01M 2/12 20060101 H01M002/12; H01M 6/42 20060101
H01M006/42 |
Claims
1. A thermal transfer barrier positionable adjacent to an
electrical storage cell having a vent configured to release gasses
from the cell, the thermal transfer barrier comprising: a barrier
member having a first side for orienting toward the vent on the
cell, the first side being contoured in a manner configured to
collect gas directed toward the first side of the barrier member
from the vent when released from the vent and guide the collected
gas away from a cell positioned adjacent to the cell.
2. The thermal transfer barrier of claim 1 wherein the contour of
the first side includes a concave-shaped region.
3. The thermal transfer barrier of claim 2 wherein the contour of
the first side includes a channel in communication with the
concave-shaped region.
4. The thermal transfer barrier of claim 3 wherein the concave
region is substantially centrally located on the barrier member,
and the channel of the contour extends radially outward from the
concave-shaped region.
5. A battery assembly, comprising: at least two electrical storage
cells, at least one of the cells having a vent configured to
release gasses from the cell; and a thermal transfer barrier
positioned between the at least two cells, the thermal transfer
barrier being positioned adjacent to the vent on the at least one
cell such that gasses released through the vent are directed toward
the thermal transfer barrier; wherein the thermal transfer barrier
forms a thermal barrier between the cells.
6. The battery assembly of claim 5 wherein the thermal transfer
barrier comprises an electrically non-conductive material.
7. The battery assembly of claim 5 wherein the thermal transfer
barrier comprises a non-flammable material.
8. The battery assembly of claim 5 wherein the thermal transfer
barrier comprises a ceramic material.
9. The battery assembly of claim 5 wherein the thermal transfer
barrier has a first side being contoured in a manner configured to
collect gas directed toward the first side of the barrier from the
vent when released from the vent and guide the collected gas away
from the cell positioned adjacent to the at least one cell.
10. The battery assembly of claim 9 wherein the contour of the
first side includes a concave-shaped region.
11. The battery assembly of claim 10 wherein the contour of the
first side includes a channel in communication with the
concave-shaped region.
12. The battery assembly of claim 11 wherein the concave region is
substantially centrally located on the barrier member, and the
channel of the contour extends radially outward from the
concave-shaped region.
13. A battery assembly comprising: a housing defining an interior;
at least two electrical storage cells located in the interior of
the housing; and a thermal transfer barrier located in the interior
of the housing, the thermal transfer barrier being positioned
between the at least two cells in the housing; wherein the thermal
transfer barrier is formed of a material having a greater
insulation capability than a material of the housing.
14. The battery assembly of claim 13 wherein the thermal transfer
barrier comprises an electrically non-conductive material.
15. The battery assembly of claim 13 wherein the thermal transfer
barrier comprises a non-flammable material.
16. The battery assembly of claim 13 wherein the thermal -transfer
barrier comprises a ceramic material.
17. The battery assembly of claim 13 wherein the thermal transfer
barrier has a first side being contoured in a manner configured to
collect gas directed toward the first side of the barrier from the
vent when released from the vent and guide the collected gas away
from the cell positioned adjacent to the at least one cell.
18. The battery assembly of claim 17 wherein the contour of the
first side includes a concave-shaped region.
19. The battery assembly of claim 18 wherein the contour of the
first side includes a channel in communication with the
concave-shaped region.
20. The battery assembly of claim 13 wherein the thermal transfer
barrier forms a wall in the housing positioned between the at least
two cells in the housing.
Description
BACKGROUND
[0001] 1. Field
[0002] The present disclosure relates to batteries, and more
particularly pertains to a new system for reducing thermal transfer
between cells in a battery to reduce the possibility of a cascade
thermal runaway of cells in the battery.
[0003] 2. Description of the Prior Art
[0004] The use of portable devices for various tasks has become
ubiquitous, and while the miniaturization of various components
that make up these devices is a part of their increasing
popularity, and the ability to power these devices for longer and
longer time periods has also added to the portability and ease of
use of the devices. Contributing to the improvement in the ability
to power these portable devices is the development of new battery
technologies with seemingly ever increasing charge capacities in
smaller and smaller packages.
[0005] These developments have not been without their occasional
drawbacks, and one example of this is the development of lithium
ion battery technology. While delivering relatively greater charge
capacities in relatively smaller packages, the lithium ion cells
have the potential to generate very high temperatures if there is a
failure in the circuitry or structure of the cell that causes, for
example, a short circuit. These high temperatures are not only
damaging to the battery and the device in which the lithium ion
cell is incorporated or attached, but can cause other damage by
fire if the battery continues to malfunction.
[0006] More specifically, the effort to increase the density of the
cells to provide a greater charge capacity in a smaller space has
tended to make the cells more vulnerable to defects and damage that
can cause such failures. The increasing density has been achieved
through manufacturing techniques that make the components of the
cell thinner, such as the separator between anode and cathode.
Thus, the manufacturing methods have become more critical not only
to the operation of the cell but also to the safety of the cell,
especially as the cells become denser. For example, the presence of
small metallic dust particles in the cell can cause a short circuit
in the cell if these particles come into contact with the
oppositely charged parts of the cell. Elimination of all of these
dust particles from the manufacturing process may be virtually
impossible.
[0007] While a mild short may generate only a small amount of heat
and may lead to an accelerated degree of self-discharge, the
presence of enough metal particles at one location can produce a
major electrical short and a much larger current flow between the
positive and negative plates, causing a more significant
temperature rise and possibly the condition sometimes referred to
as "thermal runaway" in which flaming gases may be vented from the
cell.
[0008] During thermal runaway of a cell, the heat generated in the
malfunctioning cell can be transferred to an adjacent cell in the
battery package, causing the adjacent cell to become thermally
unstable. This heat transfer can lead to a chain reaction in which
failure of a cell cascades to an adjacent cell, and the process may
be repeated to other cells. Thus, not only can the malfunctioning
cell of the battery be affected, but cells adjacent to the
malfunctioning cell can be exposed to the heat generated by the
malfunction and the performance and operation of the adjacent cell
can be affected, even to the point that the adjacent cells can be
caused to also malfunction. Typically, a cell will include a vent
that allows the hot gases to escape from the interior of a cell
when pressures in the interior of the cell exceed a threshold
level. The vent is typically located toward or on the end of the
cell, which often has an elongated cylindrical shape. The
positioning of the vent are the end of the cell, which is often
next to an adjacent cell, can allow the hot, pressurized gases
escaping from the malfunctioning cell to contact, and heat, the
adjacent cell, which can in turn cause overheating and excess
pressure in the adjacent cell.
[0009] It is therefore believed that there is a need in the art for
a device that increases the safety of operation of cells in a
battery, especially but not limited to lithium ion batteries, to
decrease the possibility that a malfunction in one cell of the
battery is able to propagate to another adjacent cell.
SUMMARY
[0010] In view of the foregoing disadvantages inherent in the known
battery designs, the present disclosure describes a new system for
reducing thermal transfer between cells in a battery which may be
utilized to reduce the possibility of a cascade thermal runaway of
cells in a the battery.
[0011] The present disclosure relates to a new thermal transfer
barrier that is positionable adjacent to an electrical storage cell
having a vent configured to release gasses from the cell. The
thermal transfer barrier comprises a barrier member having a first
side for orienting toward the vent on the cell. The first side is
contoured in a manner configured to collect gas directed toward the
first side of the barrier member from the vent when released from
the vent and guide the collected gas away from a cell positioned
adjacent to the cell.
[0012] In another aspect, a battery assembly comprises at least two
electrical storage cells with at least one of the cells having a
vent configured to release gasses from the cell. A thermal transfer
barrier is positioned between the at least two cells, and the
barrier is positioned adjacent to the vent on the at least one cell
such that gasses released through the vent are directed toward the
thermal transfer barrier. The thermal transfer barrier forms a
thermal barrier between the cells.
[0013] In one yet another aspect, a battery assembly comprises a
housing defining an interior and at least two electrical storage
cells located in the interior of the housing. A thermal transfer
barrier is located in the interior of the housing and is positioned
between the at least two cells in the housing. The thermal transfer
barrier is formed of a material having a greater insulation
capability than a material of the housing.
[0014] The foregoing is a general outline of some-of the more
significant aspects of the disclosure, and the detailed description
of this application that follows discloses additional features of
the disclosure which form the subject matter of the claims appended
hereto.
[0015] The advantages of the various embodiments of the present
disclosure, along with the various features of novelty that
characterize the embodiments, are disclosed in the following
descriptive matter and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The disclosure will be better understood when consideration
is given to the following detailed description thereof. Such
description makes reference to the annexed drawings wherein:
[0017] FIG. 1 is a schematic perspective view of a new thermal
transfer barrier according to the present disclosure.
[0018] FIG. 2 is a schematic sectional view of the thermal transfer
barrier, according to an illustrative embodiment, taken along line
2-2 of FIG. 1.
[0019] FIG. 3 is a schematic perspective view of the thermal
transfer barrier positioned between two adjacent cells of a
battery, according to an illustrative embodiment.
[0020] FIG. 4 is a schematic perspective view of a battery housing
with the thermal transfer barrier, according to an illustrative
embodiment.
[0021] FIG. 5 is a schematic sectional view of the battery housing
including the barrier, according to an illustrative embodiment.
[0022] FIG. 6 is a schematic sectional view of the battery housing
including the barrier, according to an illustrative embodiment.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0023] With reference now to the drawings, and in particular to
FIGS. 1 through 6 thereof, the system for reducing thermal transfer
between cells in a battery of the present disclosure generally
includes a thermal transfer barrier designated by the reference
numeral 10 in this description.
[0024] In the following detailed description of preferred
embodiment and other embodiments according to the present
disclosure, reference is made to the accompanying drawings which
form a part hereof, and in which is shown by way of illustration
specific preferred embodiments in which the invention may be
practiced. These embodiments are described in sufficient detail to
enable those skilled in the art to practice the invention, and it
is to be understood that other embodiments may be utilized and that
logical, mechanical and electrical changes may be made without
departing from the spirit or scope of the invention. To avoid
detail not necessary to enable those skilled in the art to practice
the invention, the description may omit certain information known
to those skilled in the art. The following detailed description is,
therefore, not to be taken in a limiting sense, and the scope of
the present invention is defined only by the appended claims.
[0025] The present disclosure relates to a thermal transfer barrier
10 that is highly suitable for use in a battery assembly 12 that
may comprise at least two electrical storage cells 14, 16 that
store electrical energy and discharge that electrical energy
between an anode and a cathode, such as electrolytic cells,
although the barrier 10 of the disclosure is not limited to such
applications. The thermal transfer barrier 10 of the disclosure is
suitable for use in a battery 12 that includes more than two cells,
especially for those batteries incorporating several cells, but
this description will proceed in terms of two cells 14, 16. The
thermal transfer barrier 10 is also especially suitable for use in
a battery 12 in which the cells 14, 16 are positioned in relatively
close proximity to each other in the battery.
[0026] While the thermal transfer barrier 10 is useful with
virtually any type of electrical storage cell technology, it is
especially suitable for use with storage cell technologies that
generate, or have the potential to generate, large amounts of heat
either in normal operation or during a period of malfunction. One
storage cell technology that may experience these conditions is
lithium ion-based storage. Although the usefulness of the barrier
10 is not limited to this type of cell technology, the description
will be in terms of the lithium-based technology, which has many
similarities to other electrolytic cell technologies. The cells 14,
16 are typically (but not necessarily) elongated and cylindrical in
shape, which provides ease of manufacture, high energy density and
good mechanical stability. One common size is designated as
"18650", in which "18" denotes the diameter is 18 mm and "650"
denotes the length is 65 mm. Other cell types, such as for example
button or prismatic, may be used with the system of the
disclosure.
[0027] Significantly, the cells 14, 16 may be provided with a vent
18 to release pressure from the interior of the cell developed
under extreme conditions such as excessive overcharging or physical
damage to the structure of the cell. Opening of the vent 18 may
occur at, for example, pressures between of approximately 150 psi
to approximately 200 psi (approximately 10 Bar to approximately
13.5 Bar). The vent 18 of the cell 14, 16 is typically located on
an end of the elongated cell, and sometimes on or near the positive
terminal or anode of the cell.
[0028] The battery assembly 12 may include a housing 20 which
substantially encloses the cells 14, 16 of the battery and may
perform other functions that are not relevant here, such as
providing structure for mounting the battery on a larger device,
such as, for example, a portable computer. The housing 20 may form
at least one cavity 22, with one or more of the cells 14, 16 being
positioned in the cavity 22. In some embodiments of the housing 20,
two cavities 22, 24 may be formed.
[0029] The cavities 22, 24 may be elongated to hold one, or more
than one, of the cells 14, 16, particularly when the shape of cells
14, 16 is elongated. When multiple cells 14, 16 are positioned in a
cavity, the cells 14, 16 are often positioned in an end to end
relationship, with the end (often the anode terminal) of one of the
cells 14, 16 being positioned adjacent to the end (often the
cathode terminal) of another one of the cells 14, 16. This
configuration typically positions the vent 18 on one end of the
cell in an adjacent relationship to the end of another cell in the
battery, and may orient the vent so that emissions from the vent
are directed at another cell in the battery. In other
configurations, the ends of some cells of a multiple cell battery
are positioned such that the vent on a cell is adjacent to or
directed toward an adjacent cell that may or may not be positioned
in an end to end relationship with the cell. In either of these
configurations, or others not mentioned, gases that are vented from
one cell are directed toward, and will likely come in contact with,
another cell in the housing of the battery 12. As previously noted,
the hot gases vented from one cell can contact an adjacent cell in
the battery 12 and cause that adjacent cell to also overheat and
vent hot gas. Due to the hot and pressurized character of the gases
emanating from the vent 18, an adjacent cell does not have to be in
direct contact with the venting cell to be affected by the venting
gases, and even if the cells are somewhat spaced from each other,
the venting gas of one cell may affect another cell in the battery.
The encasement of walls of the housing 12 may trap the gases and
further accentuate the heat problem. The adjacent cells 14, 16 may
be located sufficiently proximate to each other to permit gases
exiting the vent 18 of one cell 14 to contact the other of the
cells 16.
[0030] The system of the disclosure utilizes the thermal transfer
barrier 10 for positioning between two cells 14, 16, especially
when the two cells are positioned adjacent to each other. The
thermal transfer barrier 10 acts as an obstacle to the movement of
heat through the barrier. The barrier 10 may not function as a
complete barrier or obstruction to the movement of heat through the
barrier 10, although the barrier 10 should provide a substantial
impediment to the movement of heat therethrough. The thermal
transfer barrier 10 may have an additional function of guiding or
directing or diverting gases which may be vented through the vent
18 of a cell away from an adjacent cell.
[0031] In various embodiments, the barrier 10 comprises an element
that is interposed between cells, such as, for example cells that
would otherwise be adjacent to each other if not for the presence
of the barrier 10. In some configurations, the barrier 10 is
positioned adjacent to the location of the vent 18 on one of the
cells so that any gases that are vented from the vent 18 of the one
cell are directed away from the other cell. The barrier 10 may thus
be positioned between ends of adjacent cells 14, 16 in or on a
battery housing or other structure holding the cells in
position.
[0032] In some embodiments, the barrier 10 comprises a barrier
member 26 that may have a disk-like configuration. The barrier
member 26 may have a perimeter 28 with a shape that approximates
the size and shape of the cells 14, 16 between which the barrier
member 26 is positioned. The perimeter 28 of the barrier member 26
may have an edge, and in some configurations the perimeter edge may
be substantially circular. The circular disc configuration may
facilitate the positioning between cells in a cavity 22 of the
housing 20.
[0033] In other embodiments, the barrier 10 comprises a barrier
wall 30 that may form a portion of the housing 20, and the barrier
wall 30 may be incorporated into the battery housing 20. The
barrier wall 30 may be positioned between and form two cavities 22,
24 of the housing 20.
[0034] In the various configurations of the embodiments, the
thermal transfer barrier 10 may have a first side 32 for
positioning toward a first one 14 of the cells, and may be
positioned toward the vent 18 of the cell 14. The surface 34 of the
first side 32 may be contoured to collect gases escaping from the
vent 18 of the first cell and may be contoured to direct those
escaping gases in a direction away from a second one 16 of the
cells which is positioned adjacent to the barrier 10. The contour
of the surface 34 of the first side 32 barrier 10 which is
positioned between the cells 14, 16 is thus able to divert gases
exiting the vent 18 of the cell 14 from an unrestricted path out of
the vent 18 and away from the cell 16. The contour of the surface
34 may extend into the first side 32 of the barrier 10, and the
contour may be such that a portion of the surface 34 is
substantially concave in character. The contour of the surface 34
may include a main portion or region 36, which may be substantially
centered on the first side 32 of the barrier 10. The main region 36
may be substantially circular perimeter shape, although the
invention is not so limited. The main region 36 may be at least
partially surrounded by a ridge 38. The ridge 38 may be
substantially annular in shape or configuration, such that the
ridge forms a raised area or region about the relatively depressed
region of the main region. The ridge 38 thus facilitates the
movement of gases expelled in the direction of the first side 32
are guided or directed toward the main region 36. The contour of
the surface 34 of the first side 32 may also include a channel
region 40 extending outwardly from the main region 26 and through
the ridge 38. The channel region may extend radially outward from
the main region 36. The path of the channel region 40 may extend
substantially perpendicularly to a longitudinal axis of the cell
adjacent to which the barrier is positioned. The channel region 40
is thereby able to channel or direct gases collected in the main
region 36 of the contour of the surface 34 of the first side 32 in
a desired direction, while the presence of the barrier 10 tends to
block the gases from reaching and contacting the adjacent cell.
[0035] The thermal transfer barrier 10 may have a second side 42
that is positioned toward the second cell 16 when the first side 32
is positioned toward the second side 42. Optionally, the surface of
the second side 42 may be contoured in a manner similar to the
contour of the first side to direct gasses from the second cell 16
in a direction away from the first cell 14 that may be positioned
adjacent to the first side 32.
[0036] In various embodiments, the thermal transfer barrier 10
comprises a thermally insulative material that resists the transfer
or communication of heat from one side of the barrier to an other
side of the barrier so that heat transferred to the barrier by one
cell is not transferred in any meaningful degree to the cell on the
other side of the barrier. For example, the housing 20 of a battery
12 is commonly formed of a hydrocarbon plastic which may be
distorted or even caused to catch fire by intense heat, such as the
heat that is present in the gases that may be vented from a cell,
which maybe at 300 degrees Fahrenheit or more. The thermal transfer
barrier may be formed of a material with higher resistance to
deformation when exposed to heat of the temperature of the gases
exhausted by the cell when a malfunction occurs. The material of
the barrier 10 may differ from the material which forms the
remainder of the housing in the heat resistance characteristic.
Thus, those portions of the housing 20 that are not directly
exposed to the heated outgases may be formed of cheaper and lighter
weight materials while the barrier 10, which may be directly
exposed to the outgases, is formed of a relatively more heat
resistant material.
[0037] In some embodiments, the thermal transfer barrier 10 is
formed of a material that experiences a phase change when exposed
to the heat of the temperature of the hot gasses escaping from the
vent 18, so that the heat absorption of the barrier is
increased.
[0038] The thermal transfer barrier 10 may comprise an electrically
non-conductive, or electrically insulative, material that does not
conduct electricity between the adjacent cells. In some
embodiments, a conductor 44 may be utilized to electrically connect
a terminal on one side of the barrier 10 to a terminal on the other
side of the barrier.
[0039] The thermal transfer barrier 10 may further comprise a
non-flammable material that is not readily ignited and thus is
unlikely to combust when exposed to high temperatures such as the
range of temperatures that might be present when gas is exhausted
through the vent of a malfunctioning cell for, for example, the
lithium-ion type.
[0040] The thermally-insulative, electrically non-conductive, and
non-flammable material of the barrier 10 may comprise a
non-metallic material, and may comprise a non-hydrocarbon-based
material. Illustratively, the material of the barrier may comprise
a ceramic material, although those skilled in the art are aware of
other suitable thermally and electrically insulating materials that
are non-flammable.
[0041] Aspects of the invention are disclosed in the foregoing
description and related drawings directed to specific embodiments
of the invention. Alternate embodiments may be devised without
departing from the scope of the invention. Additionally, well-known
elements of the invention will not be described in detail or will
be omitted so as not to obscure the relevant details of the
invention. Although specific embodiments have been illustrated and
described herein, it should be appreciated that any arrangement
calculated to achieve the same purpose may be substituted for the
specific embodiments shown. This disclosure is intended to cover
any and all adaptations or variations of various embodiments. It is
to be understood that the above description has been made in an
illustrative fashion, and not a restrictive one. Combinations of
the above embodiments, and other embodiments not specifically
described herein will be apparent to those of skill in the art upon
reviewing the above description. Thus, the scope of various
embodiments includes any other applications in which the above
compositions, structures, and methods are used.
[0042] As the following claims reflect, inventive subject matter
lies in less than all features of a single disclosed embodiment.
Thus the following claims are hereby incorporated into the Detailed
Description, with each claim standing on its own as a separate
preferred embodiment. In the appended claims, the terms "including"
and "in which" are used as the plain-English equivalents of the
respective terms "comprising" and "wherein," respectively.
Moreover, the terms "first," "second," and "third," etc. are used
merely as labels, and are not intended to impose numerical
requirements on their objects. Further, where the term
"substantially" is used, it is intended to mean "for the most part"
or "being largely but not wholly that which is specified".
* * * * *