BACKGROUND
TECHNICAL FIELD
Embodiments of the invention relate to rechargeable batteries. Other
embodiments relate to a method and apparatus for assembling a rechargeable battery.
BACKGROUND
Energy storage devices may have challenges with damage and
manufacturability. Loosely packaged batteries may result in vibration or shaking, which
may damage the energy storage cells or connections between the energy storage cells,
especially when the batteries are used in vehicles or other moving platforms.
It may be desirable to have a battery package that differs from those packages
that are currently available.
SUMMARY
Presently disclosed is a method of assembling a rechargeable battery. In an
embodiment, the method includes inserting rechargeable energy storage cells into a
battery housing, the battery housing having a base portion, a side portion extending from
the base portion, and an aperture defined by the side portion, wherein the rechargeable
energy storage cells are inserted into the battery housing through the aperture; installing
an insulator on the rechargeable energy storage cells; and securing a housing cover to the
battery housing such that the insulator and the rechargeable energy storage cells are
maintained in compression between the housing cover and the housing base portion.
Also disclosed is a rechargeable battery. In an embodiment, a battery housing
having a base portion, a side portion extending from the base portion, and an aperture
defined by the side portions; a housing cover secured to the battery housing; a plurality of
rechargeable energy storage cells disposed within the battery housing with at least a
portion of the energy storage cells electrically connected to one another; and an insulator
disposed between the rechargeable energy storage cells and the housing cover; wherein
the insulator and the energy storage cells are maintained in compression between the
housing cover and the housing base portion.
2
In another embodiment, the rechargeable battery comprises a battery housing
having a base portion, a side portion extending from the base portion, and an aperture
defined by the side portions. The rechargeable battery further comprises a housing cover
secured to the side portion of the battery housing and covering the aperture. The
rechargeable battery further comprises a plurality of electrically interconnected,
rechargeable energy storage cells disposed within the battery housing. The rechargeable
battery further comprises a plurality of mica sheets disposed between the rechargeable
energy storage cells and the housing cover. The plurality of mica sheets and the energy
storage cells are maintained in compression between the housing cover and the housing
base portion, for inhibiting movement of the energy storage cells between the housing
cover and the housing base portion. The amount of compression comprises: 1.7 kpa or
more of compressive force; and/or a compressive force suitable to compress the plurality
of mica sheets by at least 5% in the vertical dimension from an uncompressed state of the
plurality of mica sheets.
BRIEF DESCRIPTION OF DRAWINGS
Reference is made to the accompanying drawings in which particular
embodiments and further benefits of the invention are illustrated as described in more
detail in the description below, in which:
FIG. 1 is a perspective view of an energy storage device;
FIG. 2 is a perspective view of an enclosure for an energy storage device;
FIG. 3 is a perspective view of another enclosure for an energy storage device;
FIG. 4 is a perspective view of another enclosure for an energy storage device;
FIG. 5 is a perspective view of another enclosure for an energy storage device;
FIG. 6 is a perspective view of a cover for an energy storage device enclosure;
FIG. 7 is a perspective view of another cover for an energy storage device
enclosure;
FIG. 8 is a perspective view of another cover for an energy storage device
enclosure;
FIG. 9 is a perspective view of another cover for an energy storage device
enclosure; and
3
FIG. lOis a cross-section view of an energy storage device.
DETAILED DESCRIPTION
The subject matter disclosed herein relates to an enclosure for an energy
storage device, such as a rechargeable battery. Referring generally to FIGS. 1 through
10, embodiments of an enclosure for an energy storage device and a method for
packaging an energy storage device are disclosed. The enclosure for an energy storage
device may support a wide variety of electrochemical cells, such as sodium-halide (e.g.,
sodium-metal-halide), sodium-sulfur, lithium-sulfur, and other available electrochemical
cells used for energy storage. In one embodiment, the electrochemical cells have an
operating temperature determined by the melting point of the materials utilized in the
cells. For example, the operating temperature may be at least or greater than about 100
degrees Celsius, such as between 250 degrees Celsius and 400 degrees Celsius, or
between 400 degrees Celsius and 700 degrees Celsius, but other desired operating
temperatures are possible. In one embodiment, the operating temperature is between 250
and 350 degrees Celsius.
In some embodiments, the rechargeable energy storage cells have dimensions
of about 37mm x 27mm x 240mm, any of which dimensions may vary by up to +/- 50%,
in accordance with various embodiments. In other embodiments, the energy storage cells
may have a diameter of about 10mm and a length of between l10mm and 2l0mm. In
embodiments, the chemistry of a cell is of the sodium-metal-halide type, in which NaCI
and Ni are converted to Na and NiCh during battery charging. The energy capacity of an
energy storage cell can range from about 2 amp*hours to about 250 amp*hours. The
rechargeable battery includes a plurality of energy storage cells with the battery housing
sized to accommodate the plurality of energy storage cells. In one embodiment, the
rechargeable battery includes one hundred energy storage cells and the battery housing
has dimensions of about 400mm x 300mm x 300mm. In other embodiments, the
rechargeable battery may include at least 20 cells, at least 50 cells, or at least 150 cells,
with the battery housing sized accordingly. In some embodiments, the battery housing is
sized to accommodate more energy storage cells than are provided in the rechargeable
battery. For example, a battery housing may accommodate up to 50 cells, but the
4
rechargeable battery may be populated with only 40 cells based on the electrical
requirements, and the remaining space within the housing may be occupied by a packing
material or other support to inhibit movement of the battery cells disposed within the
battery housing.
In various embodiments, a rechargeable battery includes a battery housing
having a base portion, side portions extending from the base portion, and an aperture
defined by the side portions. The rechargeable battery also includes a housing cover
secured to the battery housing with a plurality of rechargeable energy storage cells
disposed within the battery housing. In one embodiment, the energy storage cells are
electrically connected by welded connections between the respective positive and
negative terminals of the energy storage cells. The rechargeable battery also includes an
insulator disposed between the rechargeable battery cells and the housing cover that
inhibits movement of the energy storage cells and avoid stress to the welded intercell
connections. In one embodiment, the housing includes a peripheral edge defining an
aperture distal from the base portion through which the rechargeable energy storage cells
are inserted into the interior volume of the battery housing. The aperture is sized to
receive the one or more electrochemical cells during assembly of the rechargeable
battery. In various embodiments, the insulator disposed between the energy storage cells
and the housing cover is formed of one or more materials that are electrically or
thermally insulating, or both. In one embodiment, the insulator includes discrete portions
where a first portion such as an outer covering of the insulator is electrically insulating,
while a second portion such as an interior portion of the insulator is thermally insulating.
In one embodiment, the housing cover is securable to the peripheral edge of the battery
housing. In this manner, the housing and cover are configured to contain at least one
electrochemical cell at an operating temperature that is greater than about 100 degrees
Celsius. In some embodiments, the housing and cover are configured to house
electrochemical cells operating at temperatures greater than about 250 degrees Celsius, or
greater than about 400 degrees Celsius.
Referring to FIG 1, a cutaway of an embodiment of a rechargeable battery
assembly 100 is illustrated. In the embodiment shown, the rechargeable battery includes
a battery housing 102 for receiving one or more rechargeable energy storage cells 104. A
5
cover 108 is secured to the battery housing 102 to enclose the cells 104 within the
housing. An insulator 106 is provided between the housing cover 108 and the cells 104.
In one embodiment, the insulator 106 includes a material having sufficient thickness in
the direction "D" (see FIG 10) between the housing cover and the housing base such that
when the cover 108 is secured to the battery housing 102, pressure is applied to the
insulator and to the cells 104 to inhibit movement of the cells. In some embodiments,
when the housing 102 is enclosed by the cover 108, the insulator 106 is compressed.
FIG 2 illustrates a perspective view of an embodiment of the battery housing
102. The housing 102 includes a base portion 110 and side portions 112 extending
substantially perpendicular to the base portion 110 to form an aperture 114. In the
embodiment illustrated, the base portion 110 is a rectangle and the battery housing 102
includes four side portions 112 arranged about the perimeter of the base portion 110. The
aperture 114 therefore has a rectangular profile. Further, according to the illustrated
embodiment, the side portions 112 are joined to one another in an abutting relationship.
According to various other embodiments of the battery housing 102 the base
portion 110 may have a circular, hexagonal, oval, or other shaped profile and the side
portions 112 extend from the perimeter of the base portion 110 to form the aperture 114.
According to further variations, the side portions 112 may extend at an angle other than
perpendicular to the base portion 110, or may be of unequal height, defining an irregular
aperture 114.
Further embodiments of the battery housing 102 are shown and described with
reference to FIGS. 3-6. According to the embodiment shown in FIG 3, the side portions
112 of the housing 102 terminate at a top edge. According to a second embodiment, such
as that shown in FIG 4, attached to the side portions 112 may be a perimeter edge 116
extending about the open side of the aperture 114. According to the embodiment
illustrated in FIG 5 the perimeter edge 116 extends away from the aperture 114 and may
be perpendicular to the side portion 112. According to the embodiment illustrated in FIG
6, the perimeter edge 116 may extend into the aperture 114 and be perpendicular to the
side portion 112. In various alternative embodiments, the perimeter edge 116 may extend
at an acute or obtuse angle relative to the side portion 112 and may be bent, rolled,
curved, or otherwise extend into or away from the aperture 114.
6
According to one embodiment, the housing 102 is constructed of a single
stamped piece of metal. However, other fabrication methods are contemplated, including
welding, extrusion, assembly with fasteners, casting, or other metal fabrication method or
combination of fabrication methods. In one embodiment, the battery housing is a deep
drawn enclosure. A deep drawn enclosure is formed from material, such as a section of
sheet metal, that is press formed one or more times to achieve the desired configuration.
In one embodiment, press forming includes stamping a section of steel metal using a die
to alter the shape of the metal. The resulting deep drawn enclosure retains the continuity
of the original material avoiding the formation of seams or other discontinuities. A deep
drawn enclosure is a monolithic structure consisting of a single unbroken component.
Shown in FIGS. 7-10 are a variety of embodiments illustrating various covers.
According to an embodiment, shown in FIG. 7, the cover 108 may be a planar member
that has a profile matching the aperture 114. According to another embodiment, the
cover 108 may include a channel 118 as shown in FIG. 8 for engaging the perimeter edge
116, for example in a sliding arrangement. According to another aspect shown in FIG. 9,
the cover 108 may include a plug 120 to be received within the aperture 114 and the
planar portion of the cover 108 may engage the side portions 112 or perimeter edge 116.
According to yet another aspect, the cover 108 may include a lip edge 122 which may
surround the side portion 112 when the cover 108 is positioned over the aperture 114.
According to the embodiment illustrated in FIG. 1, the rechargeable battery
assembly 100 also includes an insulator 106 that provides thermal and electrical
insulation between at least the cover 108 and rechargeable energy storage cells 104.
According to various aspects of this embodiment, the insulator 106 may be constructed
from Teflon® or other brand PTFE, fiberglass, mica, or other thermal and/or electrical
insulator.
According to a first arrangement, the insulator 106 includes sheets of a
substantially rigid insulating material that resists deformation when compressed, such as
one or more mica sheets, arranged either in an overlapping, side-by-side, or stacked
arrangement. According to alternative arrangements, the insulator 106 is a deformable
insulation, such as woven fiberglass, that may compress, deform, and change in shape
when a force is applied.
7
With regard to the first embodiment, the insulator 106 is positioned between
the rechargeable energy storage cells 104 and cover 108 and a compressive force is
applied to the cover 108. According to one aspect, this compressive force is at least 0.25
pounds per square inch ("psi") (at least 1.7 kpa). Alternatively or additionally, the
compressive force may be sufficient to compress the insulator 106 at least 5% in the
vertical dimension from its uncompressed state. Various methods for achieving this
arrangement may be used, as will be described later with reference to the various
arrangements of the housing 102 and cover 108.
Also disclosed is a method of assembling a rechargeable battery.
Rechargeable energy storage cells 104 are inserted into a battery housing 102 having a
base portion 110 and side portions 112 extending from the base portion 110 defining an
aperture 114. The rechargeable energy storage cells 104 may be inserted through the
aperture 114. An insulator 106 is provided on the rechargeable energy storage cells 104
and a housing cover 108 is secured to the housing 102 so as to compress the insulator
106. The method of assembling a rechargeable battery may also include evacuating the
rechargeable battery after securing the housing cover to the battery housing. In an
embodiment, the battery housing includes a sealable port configured for evacuating the
interior of the battery housing such that the rechargeable energy storage cells are
maintained at a reduced pressure. In one embodiment, the reduced pressure is a
substantial vacuum that is maintained once the sealable port is sealed after evacuating the
battery housing.
According to various embodiments of the above-described method, the battery
housing 102 may include additional structure for supporting, engaging, receiving, or
locking the rechargeable energy storage cells 104 in the housing 102. This structure may
include, without limitation, clasps, rails, lips for frictional engagement, fasteners,
openings for receiving fasteners, recesses, or other engagement structure.
Also according to various embodiments, the insulator 106 may include
Teflon® or other brand PTFE, mica, fiberglass, or other thermal and electrical insulator.
The insulator 106 may have a low ratio between applied force and displacement, such as
woven fiberglass, or may have a high ratio, such as mica sheets. The compression ratio
8
may alter the amount of force applied to the cover 108 in order to protect the
rechargeable energy storage cells 104 against displacement due to vibration or damage.
According to the first embodiment, the cover 108 is secured to the housing
102 in order to provide a compression force to the insulator 106, thereby securing the
rechargeable battery cells 104 against vibration forces.
According to a first aspect of this embodiment, the cover 108 may be first
placed on the insulator 106. Next, a force may be applied to the cover 108 to compress
the insulator 106 and electrochemical cells 104, either by deforming the insulator 106,
some portion of the electrochemical cells 104, or some portion of the housing 102 (such
as a bottom insulating layer or springs, not shown). This deformation will allow the
cover 108 to contact the housing 102, whereby the cover 108 is secured to the housing by
means of welding, fasteners, or other type of permanent or semi-permanent connection.
According to this aspect, the compression force may be at least 0.25 psi (at least 1.7 kpa).
In other embodiments, the compressive force may be at least 0.5 psi, or at least 1.0 psi.
The level of compression force used in any given application will vary depending on the
expected amplitude of the vibration of the rechargeable electrochemical cells 104.
According to another aspect, screws, nails, or other mechanical fasteners are
used to secure the cover 108 to the housing 102. According to this aspect, the cover 108
includes through holes (not shown) and the perimeter edge 116 includes counter-fasteners
(not shown), such as nuts, for receiving the fasteners. The cover 108 is first placed on the
insulator 106 and screws are inserted into the through holes to engage the counterfasteners.
The screws may then be tightened, driving the cover 108 to the housing 102,
thereby compressing the insulator 106 through displacement. According to one
arrangement, the insulator 106 may be compressed by 10% of its thickness. In this
aspect, the length of the fasteners will depend on the type of insulator chosen.
According to a further aspect of the invention, the cover 108 may include a
channel 118 for slideably engaging the perimeter edge 116 of the housing 102. A
compressive force may be applied to the insulator 106, for example at least 0.25 psi (at
least 1.7 kpa), and the cover 108 may be slid on to the housing 102, thereby maintaining
the compression by means of the interaction between the channel 118 and perimeter edge
9
116. According to one arrangement, once the cover 108 is in a secured position the cover
108 may be welded, fastened, or otherwise permanently secured to the housing 102.
According to a further aspect of the invention, the insulator 106 may have a
thermal expansion rate so that the thickness of the insulator varies with ambient
temperature. The insulator 106 is maintained at a base temperature during assembly
whereby the insulator 106 is in an unexpanded state. Owing to the high operating
temperature of the energy storage device, the temperature within the housing 102 will
increase during operation, thereby causing the insulator 106 to try to expand. As heated
cells expand, greater compression of the insulating material may result depending upon
the coefficient of expansion of the materials used to construct the energy storage cells, the
insulation, and the housing. However, expansion of the insulator 106 will be resisted by
the cover 108, thereby providing the necessary compressive force against vibration.
According to one variation, once thermally activated the insulator 106 maintains its
expanded state even when the temperature is lowered. According to an alternative
variation, the insulator 106 may be thermally responsive, expanding when heated and
contracting when cooled.
According to a further aspect of the invention, the insulator 106 may be
provided in an unexpanded state and expand upon contact with the air or other some
other accelerator, such as a chemical accelerant. In this aspect, the cover 108 is
positioned on the housing 102 when the insulator 106 is in an unexpanded state and the
insulator 106 is allowed to expand after the cover 108 is secured to the housing 102.
According to one variation, the insulator 106 may be provided on the rechargeable
electrochemical cells 104 prior to the cover 108 being positioned on the housing 102.
The cover 108 is then secured to the housing 102 and the insulator 106 is allowed to
expand, thereby providing a compressive force. According to another variation, the
insulator 106 may require an accelerator to expand. The insulator 106 may be provided
on the rechargeable electrochemical cells 104 and the cover 108 secured to the housing
102. The cover 108 according to this variation includes an opening or through hole for
receiving the accelerator. Once the insulator 106 receives the accelerator, the insulator
may expand, thereby causing the desired compression force between the rechargeable
electrochemical cells 104 and cover 108.
10
According to a further aspect of the invention, a combination of insulators
may be provided. According to one variation of this aspect, a first insulator 106, such as
a rigid mica sheet, is provided across the electrochemical cells 104 to provide structural
support. A second insulator, such as a foaming insulation, is then provided between the
rigid mica sheet and the cover 108, thereby providing the necessary compression force
for securing the electrochemical cells 104 against vibration. According to another
variation of this aspect, an easily deformable insulator 106, such as fiberglass, is first
provided onto the electrochemical cells 104 to protect terminals or other components of
the cells 104. A second, more rigid insulator 106, such as a mica sheet, is then provided
over the first insulator, thereby providing additional structure and insulation. According
to yet another variation a first insulator exhibiting high electrical resistance is provided
across the electrochemical cells 104 and a second insulator exhibiting high thermal
resistance is provided between the first insulator and the cover 108. Various other
embodiments may also be appreciated.
In the specification and claims, reference will be made to a number of terms
that have the following meanings. The singular forms "a", "an" and "the" include plural
referents unless the context clearly dictates otherwise. Approximating language, as used
herein throughout the specification and claims, may be applied to modify any quantitative
representation that could permissibly vary without resulting in a change in the basic
function to which it is related. Accordingly, a value modified by a term such as "about"
is not to be limited to the precise value specified. In some instances, the approximating
language may correspond to the precision of an instrument for measuring the value.
Similarly, "free" may be used in combination with a term, and may include an
insubstantial number, or trace amounts, while still being considered free of the modified
term. Moreover, unless specifically stated otherwise, any use of the terms "first,"
"second," etc., do not denote any order or importance, but rather the terms "first,"
"second," etc., are used to distinguish one element from another.
As used herein, the terms "may" and "may be" indicate a possibility of an
occurrence within a set of circumstances; a possession of a specified property,
characteristic or function; and/or qualify another verb by expressing one or more of an
ability, capability, or possibility associated with the qualified verb. Accordingly, usage
11
of "may" and "may be" indicates that a modified tenn is apparently appropriate, capable,
or suitable for an indicated capacity, function, or usage, while taking into account that in
some circumstances the modified tenn may sometimes not be appropriate, capable, or
suitable. For example, in some circumstances an event or capacity can be expected,
while in other circumstances the event or capacity cannot occur - this distinction is
captured by the tenns "may" and "may be." The tenns "generator" and "alternator" are
used interchangeably herein (however, it is recognized that one tenn or the other may be
more appropriate depending on the application). The tenn "instructions" as used herein
with respect to a controller or processor may refer to computer executable instructions.
This written description uses examples to disclose the invention, including the
best mode, and also to enable one of ordinary skill in the art to practice the invention,
including making and using any devices or systems and perfonning any incorporated
methods. The patentable scope of the invention is defmed by the claims, and may include
other examples that occur to one of ordinary skill in the art. Such other examples are
intended to be within the scope of the claims if they have structural elements that do not
different from the literal language of the claims, or if they include equivalent structural
elements with insubstantial differences from the literal language of the claims.
12
PARTS LIST
100 rechargeable battery assembly
102 housing
104 cell
106 insulator
108 cover
110 base portion
e 112 side portion
114 aperture
116 perimeter edge
120 plug
122 lip edge

We Claim:
1. A method of assembling a rechargeable battery comprising:
inserting rechargeable energy storage cells into a battery housing, the battery
housing having a base portion, a side portion extending from the base portion, and an
aperture defined by the side portion, wherein the rechargeable energy storage cells are
inserted into the battery housing through the aperture;
installing an insulator on the rechargeable energy storage cells; and
securing a housing cover to the battery housing such that the insulator and the
rechargeable energy storage cells are maintained in compression between the housing
cover and the housing base portion.
2. The method of assembling a rechargeable battery as claimed in claim 1, wherein
the insulator comprises a plurality of mica sheets.
3. The method of assembling a rechargeable battery as claimed in claim 2, wherein
installing the insulator on the rechargeable energy storage cells further comprises
installing the plurality of mica sheets such that the mica sheets extend through a plane
defined by the perimeter ofthe aperture ofthe battery housing.
4. The method of assembling a rechargeable battery as claimed in claim 1, wherein
the insulator is compressed at least 5% in the direction between the base portion and
the housing cover when the housing cover is secured to the battery housing.
5. The method of assembling a rechargeable battery as claimed in claim 1, wherein
securing the housing cover to the battery housing comprises applying at least 1.7 kpa
of force to the housing cover to compress the insulator.
6. The method of assembling a rechargeable battery as claimed in claim 1, wherein
the compression of the insulator inhibits movement of the energy storage cells in a
direction between the housing cover and the housing base portion.
l'i
7. The method of assembling a rechargeable battery as claimed in claim 1, wherein
the side portion of the battery housing comprises four sides forming a substantially
rectangular cross-section ofthe battery housing.
8. The method of assembling a rechargeable battery as claimed in claim 1, wherein
the battery housing comprises a deep drawn enclosure.
9. The method of assembling a rechargeable battery as claimed in claim 1, wherein
the side portion of the battery housing is welded to the base portion to form the
battery housing.
10. The method of assembling a rechargeable battery as claimed in claim 1, wherein
the housing cover is secured to the battery housing by welding.
11. The method of assembling a rechargeable battery as claimed in claim 1, wherein
the housing cover is secured to the battery housing by mechanical fasteners.
12. The method of assembling a rechargeable battery as claimed in claim 1, further
comprising the step of evacuating the rechargeable battery after securing the housing
cover to the battery housing.
13. The method of assembling a rechargeable battery as claimed in claim 1, wherein
the rechargeable energy storage cells are sodium-halide cells.
14. A rechargeable battery comprising:
a battery housing having a base portion, a side portion extending from the base
portion, and an aperture defined by the side portions;
a housing cover secured to the battery housing;
a plurality of rechargeable energy storage cells disposed within the battery
housing with at least a portion ofthe energy storage cells electrically connected to one
another; and
an insulator disposed between the rechargeable energy storage cells and the
housing cover;
wherein the insulator and the energy storage cells are maintained in
compression between the housing cover and the housing base portion.
15. The rechargeable battery as claimed in claim 14, wherein the insulator comprises
a plurality of mica sheets.
16. The rechargeable battery as claimed in claim 14, wherein the insulator is
maintained in compression with at least 1.7 kpa of compressive force.
17. The rechargeable battery as claimed in claim 14, wherein the compression of the
insulator inhibits movement of the energy storage cells between the housing cover and
the housing base portion.
18. The rechargeable battery as claimed in claim 14, wherein said at least the portion
of the energy storage cells are electrically connected by welded connections.
19. A rechargeable battery comprising:
a battery housing having a base portion, a side portion extending from the base
portion, and an aperture defined by the side portions;
a housing cover secured to the side portion of the battery housing and covering
the aperture;
a plurality of electrically interconnected, rechargeable energy storage cells
disposed within the battery housing; and
a plurality of mica sheets disposed between the rechargeable energy storage
cells and the housing cover;
wherein the plurality of mica sheets and the energy storage cells are
maintained in compression between the housing cover and the housing base portion,
for inhibiting movement of the energy storage cells between the housing cover and
the housing base portion, and wherein said compression comprises at least one of 1.7
kpa or more of compressive force or a compressive force suitable to compress the
•
plurality of mica sheets by at least 5% in the vertical dimension from its
uncompressed state.
20. The rechargeable battery as claimed in claim 19, wherein the energy storage cells
are sodium-halide cells having an operating temperature of at least 100 degrees C.