WO2019040897A1

WO2019040897A1 - Bipolar substrate stress relieving feature

Info

Publication number: WO2019040897A1
Application number: PCT/US2018/047991
Authority: WO
Inventors: Jeffrey L. Troxel
Original assignee: Johnson Controls Technology Company
Priority date: 2017-08-24
Filing date: 2018-08-24
Publication date: 2019-02-28

Abstract

Disclosed is a battery comprising one or more bipolar plates, further comprising a substrate with at least one foil that has one or more features that alleviate stress generated in the foil by a charge/discharge cycle. Specifically, the bipolar plate may include a substrate with a foil on at least one side of the substrate that includes at least one stress-relieving feature at each of a plurality of solder joints at which the foil is attached to the substrate.

Description

BIPOLAR SUBSTRATE STRESS RELIEVING FEATURE

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to United States Provisional Patent Application Number 62/549,597 filed August 24, 2018 the entirety of which is incorporated herein by reference.

FIELD

[0002] This application relates to the field of batteries. More particularly, this application relates to features provided inside of electrochemical batteries.

BACKGROUND

[0003] Bipolar batteries include several cells within the same housing. Each cell in a bipolar battery may include at least one plate with a positive side and a negative side; a "bipolar plate." This format is distinguishable from traditional monopolar batteries, which include several cells each within their own housing and a plurality of plates (positive and negative) per cell.

[0004] In a bipolar battery, a bipolar substrate separates and is the connection element between adjacent cells. Bipolar plates therefore may have a shorter current path and larger surface area than connectors in traditional monopolar cells. As such, bipolar plates may offer a reduction in power loss normally caused by the internal resistance of cells.

[0005] When loading or drawing charge from a bipolar battery (such as when the battery undergoes a charge/discharge cycle), the positive side of the bipolar plate may undergo a volume change. In other words, the positive side of the bipolar plate may change shape during the charge/discharge cycle, for example, as a result of battery (for example, lead-acid) chemistry. Such stress may cause corrosion, for example at solder joints in the battery. This may cause battery active material to separate from battery foil layer(s) and/or may cause foil to separate from battery substrate. Any of these conditions may lead or contribute to battery failure.

[0006] Therefore, what is needed is a solution which allows for, among other things, alleviation of stress generated in the battery.

SUMMARY

[0007] The disclosed device and method in various embodiments seeks to provide a solution to these and other problems in a battery. For example, the disclosed may include a stress- relieving feature which may be provided as part of a bipolar plate, in various embodiments.

[0008] Some embodiments advantageously provide a bipolar plate, such as a bipolar plate used in a lead-acid battery, which includes a substrate with at least one foil that has one or more features that alleviate stress generated in the foil by a charge/discharge cycle. Specifically, the bipolar plate may include a substrate with a foil on at least one side having a stress-relieving feature at each of a plurality of solder joints at which the foil is attached to the substrate. The stress- relieving features may be configured to allow the foil to expand, contract, shift, buckle, flex, or otherwise move in response to forces (such as lateral forces) or stresses acting on the foil as a result of the battery's charge/discharge cycle. This stress-relieving feature may advantageously allow for movement without compromising the integrity of the solder joints.

[0009] Disclosed in various embodiments is a bipolar plate for a bipolar battery that includes: a substrate having a first surface and a second surface opposite the first surface; a first foil affixed to the first surface of the substrate; and a second foil affixed to the second surface of the substrate, the first foil including at least one stress-relieving feature, the at least one stress-relieving feature having at least one deformable area. Further disclosed in various embodiments is a bipolar battery wherein a first foil includes a first surface and a second surface opposite the first surface, the z, second surface of the first foil being affixed to the first surface of the substrate and the at least one stress-relieving feature including a plurality of stress- relieving features. Further disclosed in various embodiments is a bipolar battery wherein a plurality of stress-relieving features are symmetrically arranged on the first surface of the first foil. Further disclosed in various embodiments is a bipolar battery wherein a deformable area of each of the at least one stress-relieving feature is an annular ridge. Further disclosed in various embodiments is a bipolar battery wherein each of the at least one stress-relieving feature includes a planar central point. Further disclosed in various embodiments is a bipolar battery wherein a first foil is affixed to the first surface of the substrate at the planar central point of each of the at least one stress-relieving feature. Further disclosed in various embodiments is a bipolar battery wherein the first foil is soldered to the first surface of the substrate at the planar central point of each of the at least one stress-relieving feature. Further disclosed in various embodiments is a bipolar battery wherein the deformable area of each of the at least one stress- relieving feature is configured such that the deformable area is movable relative to the planar central point. Further disclosed in various embodiments is a bipolar battery wherein the at least one stress- relieving feature includes a plurality of stress-relieving features, the first foil further including a planar area between the plurality of stress-relieving features, each of the plurality of stress-relieving features being configured such that the deformable area is movable relative to the planar area.

Further disclosed in various embodiments is a bipolar battery wherein each of the plurality of stress- relieving features further has a planar central point that is coplanar with the planar area. Further disclosed in various embodiments is a bipolar battery wherein the first foil is soldered to the first surface of the substrate at the planar central point of each of the plurality of stress-relieving features. Further disclosed in various embodiments is a bipolar battery wherein the first foil is coated in a layer of positive active material and the second foil is coated in a layer of negative active material. Further disclosed in various embodiments is a bipolar battery wherein each of the at least one stress-relieving feature has a height, the layer of positive active material having a thickness that is at greater than the height.

[0010] Disclosed in various embodiments is a foil for a bipolar plate for use in a bipolar battery which includes: at least one stress-relieving feature, the at least one stress-relieving feature including a deformable area and a planar central point. Further disclosed in various embodiments is a stress relieving feature wherein the deformable area surrounds the planar central point. Further disclosed in various embodiments is a stress relieving feature wherein the deformable area is an annular ridge. Further disclosed in various embodiments is a stress relieving feature wherein the deformable area is configured to be movable relative to the planar central point. Further disclosed in various embodiments is a foil for a bipolar plate wherein at least one stress-relieving feature includes a plurality of stress-relieving features, the foil further comprising: a first surface and a second surface opposite the first surface, the plurality of stress-relieving features being on the first surface; and a planar area on the first surface between the plurality of stress-relieving features, the planar central point of each of the plurality of stress-relieving features being coplanar with the planar area.

[0011] Disclosed in various embodiments is a bipolar battery comprising: a housing; and at least one bipolar plate within the housing, each of the at least one bipolar plate including: a substrate having a first surface and a second surface opposite the first surface; a first foil affixed to the first surface of the substrate, the first foil including a plurality of stress-relieving features, each of the plurality of stress-relieving features including a deformable area and a planar central point, the first foil being affixed to the first surface of the substrate at the planar central point of each of the plurality of stress-relieving features, the deformable area being movable relative to the planar central point when the deformable area is acted upon by a stress force; and a second foil affixed to the second surface of the substrate. Further disclosed in various embodiments is a bipolar battery wherein the first foil is coated with a layer of positive active material and the second foil is coated with a layer of negative active material. Further disclosed is a bipolar battery wherein the housing includes a first end and a second end opposite the first end, the first foil is a positive foil, and the second foil is a negative foil. Further disclosed is a bipolar battery which further includes a negative monopolar plate at the first end of the housing, the negative monopolar plate being proximate the positive foil, and a positive monopolar plate at the second end of the housing, the positive monopolar plate being proximate the negative foil.

[0012] These and other features and advantages of devices, systems, and methods according to this invention are described in, or are apparent from, the following detailed descriptions of various examples of embodiments.

BRIEF DESCRIPTION OF DRAWINGS

[0013] Various examples of embodiments of the systems, devices, and methods according to this invention will be described in detail, with reference to the following figures, wherein:

[0014] FIG. 1 shows an illustration of an example bipolar battery having a plurality of bipolar battery cells;

[0015] FIG. 2 shows an illustration of a bipolar battery having a plurality of bipolar battery cells which may include the stress-relieving feature according to various embodiments;

[0016] FIG. 3 shows a perspective view of a substrate having a foil with a plurality of stress- relieving features according to various embodiments;

[0017] FIG. 4 shows a close-up view of a stress-relieving feature according to various embodiments;

[0018] FIG. 5 shows a cross-sectional view of a stress-relieving feature according to various embodiments; [0019] FIG. 6 shows a first step of a method of forming the foil of FIG. 3 according to various examples of embodiments;

[0020] FIG. 7 shows a second step of a method of forming the foil of FIG. 3 according to various examples of embodiments;

[0021] FIG. 8 shows a third step of a method of forming the foil of FIG. 3 according to various examples of embodiments;

[0022] FIG. 9 shows a cross-sectional view of a substrate having a two foils, one of which with a plurality of stress-relieving features according to various examples of embodiments; and

[0023] FIG. 10 shows an exemplary portion of a forming die that is configured to produce a stress-relieving feature in a foil and a piece of foil thereon according to various examples of embodiments.

[0024] It should be understood that the drawings are not necessarily to scale. In certain instances, details that are not necessary to the understanding of the invention or render other details difficult to perceive may have been omitted. It should be understood, of course, that the invention is not necessarily limited to the particular embodiments illustrated herein.

DETAILED DESCRIPTION

[0025] The system and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.

[0037] As used herein, relational terms, such as "first" and "second," "top" and "bottom," and the like, may be used solely to distinguish one entity or element from another entity or element without necessarily requiring or implying any physical or logical relationship or order between such entities or elements.

[0026] Referring now to the drawing figures in which like reference designations refer to like elements, various embodiments of battery and its components, and more particularly a bipolar battery and its components, according to various examples of embodiments are shown.

[0027] Referring to FIG. 1, an example background bipolar battery 10 is shown. Bipolar battery 10 may generally comprise a housing 12 and at least one bipolar plate 14 within the housing 12. For example, a bipolar battery 10 shown in FIG. 1 includes two bipolar plates 14, a first monopolar plate 16A within and at a first end (or positive end 71) of the housing 12, and a second monopolar plate 16B within and at a second end (or negative end 73) of the housing 12. Each bipolar plate 14 may include a substrate 18 having a positive side 75 and a negative side 77. The positive side of the bipolar plate 14 may include a first foil 20 A and the negative side of the bipolar plate 14 may include a second foil 20B. For example, each foil may be soldered, welded, or otherwise affixed or coupled to the substrate 18. This coupling may occur at or as at one or more solder joints, and may be coated with an active material. Battery chemistry may comprise, in various embodiments, a lead-acid battery. In the example of FIG. 1, each cell segment, i.e., path from positive substrate to corresponding negative substrate, may provide 2 volts of power.

[0028] Again, when loading or drawing charge from the bipolar battery 10 (such as when the battery undergoes a charge/discharge cycle), the positive side of the bipolar plate 14 may undergo a volume change during the charge/discharge cycle (for example, as a result of battery chemistry, for example lead-acid chemistry). Such stress may cause corrosion at the solder joints, may cause the active material to separate from the foil 20 (in other words, 20A or 20B) and/or may cause the foil 20 (in other words, 20A or 20B) to separate from the substrate 18, and any of which may lead to battery failure. FIG. 2 shows an illustration of a battery, for example, a cross-section of a bipolar battery which may further comprise a lead-acid battery. The bipolar battery 24 may be seen to include a plurality of battery cells, and each of the (for example, but not limited to, lead-acid battery cells) may be seen to include at least one bipolar plate 26. Like the bipolar battery 10 shown in FIG. 1, the bipolar battery 24 shown in FIG. 2 generally may include a housing 28 and at least one bipolar plate 26 within the housing 28. For example, the bipolar battery 24 shown in FIG. 2 includes two bipolar plates 26, a first monopolar plate 30A within and at a first end (or positive end 71) of the housing 28, and a second monopolar plate 30B within and at a second end (or negative end 73) of the housing 28, according to various embodiments. Each bipolar plate 26 may include a substrate 32 having a first surface 34 and a second surface 36 opposite the first surface 34 (see also FIG. 3 and FIG. 9). The bipolar battery 24 further may include a first foil (or positive foil) 38 that may be affixed or coupled (for example, but not limited to, soldered or welded) to the first surface 34 of the substrate 32 at one or more solder joints 40 (while the term "solder joint" is used, various mechanisms for affixing or coupling should be contemplated as within the scope of this disclosure). The first foil 38 may include one or more stress- relieving features 42, as discussed in greater detail below and as shown, for example, in FIG. 3.

[0029] Returning to FIG. 2, The bipolar battery 24 may further include a second foil 44

(or negative foil) that is affixed or coupled (for example, but not limited to, soldered or welded) to the second surface 36 of the substrate 32 at one or more solder joints 40 (see FIGS. 4 and 9). The second foil 44 may further comprise, in various embodiments, one or more stress-relieving features 42. For simplicity, the points of attachment between a foil 38, 44 and the substrate 32 may be referred to herein as solder joints 40, regardless of the actual method of attachment. In one or more examples of embodiments, the first foil 38 is a positive foil, the first monopolar plate 30A is a negative monopolar plate, the second foil 44 is a negative foil, and the second monopolar plate 30B is a positive monopolar plate. Bipolar battery 24 may also include a positive terminal and a negative terminal.

[0030] Referring now to FIG. 3, a substrate 32 and first foil 38 for use with a bipolar plate

26 of a bipolar battery 24, such as a lead-acid battery, according to various embodiments are shown. The substrate 32 may be sized and configured to be included in a battery cell and located within a housing 28 of the bipolar battery 24 (for example the housing 28 of the bipolar battery 24 shown in FIG. 2). The substrate 32 may have any suitable size, shape, and/or configuration, but in particular may include a first surface 34 and a second surface 36 (FIG. 9) opposite the first surface 34. In one or more embodiments, the substrate 32 may be rectangular and the first surface 34 may include a first foil 38 that includes at least one stress-relieving feature 42 and the second surface 36 may include a second foil 44 (see FIG. 9) that has a planar surface (that is, the second foil 44 may be without one or more stress-relieving features 42). Alternatively, the second foil 44 may also include at least one stress-relieving feature 42. The first 38 and second 44 foils may be configured to be affixed to the substrate 32 when the bipolar battery 24 is assembled. In one or more embodiments, the substrate 32 shown in FIG. 3 may include a positive first foil 38 on the first surface 34 and a negative second foil 44 on the second surface 36 (surface shown in FIG. 9). It may be understood that the first foil 38 (and, optionally, the second foil 44) may include more or fewer stress-relieving features than those shown in FIG. 3. For example, while the stress-relieving features may be seen arranged in essentially a 9x9 grid in FIG. 3 having various gaps (approximately 9 gaps), which may be understood to provide a total of 72 stress relieving features, it should be understood that more or less stress-relieving features are contemplated within the scope of this disclosure (for example, approximately 35 stress-relieving features in FIGS. 6 and 8). In various embodiments, between 1 and 81 stress-relieving features may be provided. [0031] The substrate 32, first foil 38, and second foil 44 may together be understood or referred to as the bipolar plate 26. In one or more embodiments, each foil 38, 44 includes a first surface 46 and a second surface 48 opposite the first surface 46, with the second surface 48 of each foil 38, 44 being affixed to either the first 34 or second 36 surface of the substrate 32, and the first surface 46 of each foil 38, 44 including one or more stress-relieving features 42 or, alternatively, the first surface of the second foil 44 may be essentially planar without stress-relieving features 42. Further, a first active material 50 (FIG. 9) may be applied to, adhered to, coupled to, layered on, or otherwise located on the first surface 46 of the first foil 38 and the second surface 48 of the first foil 38 may be coupled to the first surface 34 of the substrate 32. A second active material 52 may be applied to, adhered to, coupled to, layered on, or otherwise located on the first surface 46 of the second foil 44 and the second surface 48 of the second foil 44 may be coupled to the second surface 36 of the substrate 32 (FIG. 9). In one or more examples of embodiments, the first active material 50 may comprise a positive active material and the second active material 52 (FIG. 9) may comprise negative active material.

[0032] The first 38 and second 44 foils may be welded or soldered to the substrate 32 in one or more locations, which may be referred to herein as solder joints 40 (depicted with an "X" in FIG. 4), regardless of the actual method of attachment. In one or more examples of embodiments, the first foil 38 may include a plurality of solder joints 40 that are symmetrically arranged on the first 38 and/or second foil 44, such as in a grid distribution or pattern as shown in FIG. 3.

Alternatively, the plurality of solder joints 40 may be asymmetrically or randomly arranged on the first 38 and/or second 44 foil. A circular portion of the first foil 38 is shown in FIG. 4.

[0033] Further, the first foil 38 that may be coupled to the first surface 43 of the substrate

32 may further include a stress-relieving feature 42 at each solder joint 40. As discussed above, the charge/discharge cycle of a battery, (for example, but not limited to, a bi-polar lead-acid battery) may cause stress, such as lateral forces, to act on the battery, particularly on solder joints 40. Typically, the solder joints 40 between the foils 20 and substrate 18 of currently known bipolar plates 14 resists or opposes these forces, which can lead to corrosion at the solder joints, separation of the active material 22 from the foil 20, and/or separation of the foil 20 from the substrate 18. These stresses, as noted above, may lead to battery failure.

[0034] Unlike currently known bi-polar batteries comprising foils 20 and solder joints, the first foil 38 shown and described herein includes a stress-relieving feature 42 at each solder joint 40. As seen in FIG. 4, each stress-relieving feature 42 may include a planar central point 54 and deformable area 56 that is configured to be deformable or movable relative to the solder joint 40, planar central point 54, and/or a planar area 58 of the first foil 38 between the stress- relieving features 42.

[0035] Referring now to FIG. 4 and FIG. 5, the stress-relieving features 42 are shown and described in more detail. Each stress-relieving feature 42 may include at least one deformable area 56 that may allow the first foil 38 proximate the solder joint 40 to move when acted upon by a stress force, such as a lateral force. In various embodiments, for example but not limited to as shown in FIG. 3, the first foil 38 includes a plurality of stress- relieving features 42, at least a portion of each of which being raised relative to the planar area 58 of the first foil 38 located between the stress- relieving features 42. Put another way, each stress-relieving feature 42 includes a deformable area 56 that may be deformed without affecting or moving the solder joint 40, thus preventing or ameliorating damage to the solder joint 40. As shown in FIG. 4, for example, the deformable area 56 of each stress-relieving feature 42 may include an annular bump or ridge on the first surface of the foil that surrounds the planar central point 54. Although a single annular ridge is shown, however, it will be understood that the deformable area 56 of each stress-relieving feature 42 may include more than one annular ridge and/or one or more other ridges, bumps, or raised portions with different configurations, in various embodiments.

[0036] In one or more non-limiting examples of embodiments, the deformable area 56 of each stress-relieving feature 42 includes a first annular ridge that has a first height and a second annular ridge surrounding the first annular ridge that has a second height that is greater than, less than, or equal to the first height. In another non- limiting example, each stress-relieving feature may include a rectangular, oval, square, or polygonal ridge surrounding the planar central point. The planar central point 54 may be coplanar, or at least substantially coplanar, with the planar area 58 of the first foil 38 located between the stress- relieving features 42. Further, the location of the planar central point 54 may or may not be in the geometric center of the stress-relieving feature 42. The actual weld (e.g coupling, attachment, etc.) location between the first foil 38 and the substrate 32 may be at/within the planar central point 54 of the stress-relieving feature 42. Further, the raised portion(s) of each stress-relieving feature 42 on the first surface of the first foil 38 may comprise corresponding indented or depressed portion(s) on the second surface of the first foil 38.

[0037] Referring now to FIG. 6, FIG. 7, and FIG. 8, a method of forming a foil having a plurality of stress- relieving features 42 is shown, according to various embodiments, such as the first foil 38 described herein. In a first step shown in FIG. 6, a flat or planar foil 60 (that is, a foil without stress-relieving features) may be inserted into a machining tool, such as a forming die 62, that is configured to create a stamped first foil 38 with at least one stress-relieving feature 42 (FIG. 8). A non-limiting example of a portion of a forming die 62 being configured to produce a single stress- relieving feature 42, and a circular piece of foil 64 having been stamped by the forming die 62, may be seen in FIG. 10.

[0038] The foil 60 may be composed of any suitable material, such as (but not limited to) lead, lead alloy, or lead dioxide. In one or more examples of embodiments, the foil 60 is composed of lead dioxide for use as a positive foil. In a second step shown in FIG. 7, the forming die 62 may be closed over the foil.

[0039] After the foil 60 has been formed, the foil, now including one or more stress- relieving features 42 (in various embodiments, a plurality of stress-relieving feature) and thus being referred to with reference number 38, may be removed from the forming die 62 in a third step shown in FIG. 8. In the non-limiting example shown in FIG. 8, the first foil 38 includes a plurality of stress-relieving features 42 symmetrically arranged on the first foil 38. However, it will be understood that the forming die 62 may be configured to produce a stamped and formed first foil 38 with more or fewer stress-relieving features 42 and/or stress-relieving features 42 that have a different size, shape, configuration, or arrangement that shown in FIG. 8.

[0040] After the first foil 38 is formed, the first foil 38 may then be affixed to the substrate

32. In one or more examples of embodiments, the first foil 38 may be affixed (for example, but not limited to, welded or soldered) to the first surface 34 of the substrate 32 at several locations (solder joints 40), such as at/within the planar central point 54 of at least one of the stress-relieving features 42. In such a configuration, the area of the first foil 38 surrounding the solder joint 40 may include the deformable area 56, such as an annular ridge as shown in the figures, which may allow the first foil 38 to move when acted upon by stress forces and mitigate or prevent damage to the solder joint 40. For example, the deformable area 56 may be movable relative to the planar central point 54, the planar area 58, and/or the solder joint 40. In the non-limiting example shown in FIG. 9, the substrate 32 may include a first foil 38 on a first surface 34 and a second foil 44 on a second surface 36. Further, the first foil 38, which may be used on the positive side of the substrate 32, may include a plurality of stress-relieving features 42, whereas the second foil 44, which may be used on the negative side of the substrate 32, may not. Alternatively, the second foil 44 may also include one or more stress-relieving features 42, and may be formed in the same way as the first foil 38. [0041] After the foils 38, 44 are affixed to the substrate 32, an active material may be applied to each foil. In various examples of embodiments, a layer of an active material 50, such as a positive active material, is applied to the first surface 46 of the first foil 38 and a layer of an active material 52, such as a negative active material, is applied to the first surface 46 of the second foil 44. In various embodiments, the positive active material and the negative active material may be known active materials to support lead-acid battery chemistry. The thickness of the layers of active material 50, 52 may vary, but the layer of the active material 50 that is applied to the first foil 38 having a plurality of stress-relieving features 42 may, in various embodiments, be at least as thick as the height of the tallest stress-relieving feature 42. As a non-limiting example, the layer of active material 50 on the first foil 38 shown in FIG. 9 may be understood as shown thicker than the height of the plurality of stress-relieving features 42. If the second foil 44 also includes one or more stress- relieving features 42, the layer of active material 52 on the second foil 44 may also be thicker than the height of the tallest stress-relieving feature 42, in various embodiments. Put another way, each stress-relieving feature 42 may be completely covered by active material 50, 52. In this way, each side of the bipolar plate 26 may have a smooth surface. In various embodiments, each of the stress- relieving features in the plurality of stress-relieving features may have a same tallest height. In other embodiments, each of the stress-relieving features in the plurality of stress-relieving features may have differing heights.

[0042] In one or more examples of embodiments, a bipolar plate 26 for a bipolar battery

24 includes: a substrate 32 having a first surface 34 and a second surface 36 opposite the first surface 34; a first foil 38 affixed to the first surface 34 of the substrate 32; and a second foil 44 affixed to the second surface 36 of the substrate 32, the first foil 38 including at least one stress- relieving feature 42, each of the at least one stress-relieving feature 42 having at least one deformable area 56. In one or more aspects of one or more examples of embodiments, the first foil 38 includes a first surface 46 and a second surface 48 opposite the first surface 46, the second surface 48 of the first foil 38 being affixed to the first surface 34 of the substrate 32 and the at least one stress-relieving feature 42 including a plurality of stress-relieving features 42. In one or more aspects of one or more examples of embodiments, the plurality of stress-relieving features 42 are symmetrically arranged on the first surface 46 of the first foil 38.

[0043] In one or more aspects of one or more examples of embodiments, the deformable area 56 of each of the at least one stress-relieving feature 42 is an annular ridge. In one or more aspects of one or more examples of embodiments, each of the at least one stress-relieving feature 42 includes a planar central point 54. In one or more aspects of one or more examples of embodiments, the first foil 8 is affixed to the first surface 34 of the substrate 32 at the planar central point 54 of each of the at least one stress-relieving feature 42. In one or more aspects of one or more examples of embodiments, the first foil 38 is soldered to the first surface 34 of the substrate 32 at the planar central point 54 of each of the at least one stress-relieving feature 42. In one or more aspects of one or more examples of embodiments, the deformable area 56 of each of the at least one stress-relieving feature 42 is configured such that the deformable area 56 is movable relative to the planar central point 54. In one or more aspects of one or more examples of embodiments, the at least one stress-relieving feature 42 includes a plurality of stress-relieving features 42, the first foil 38 further including a planar area 58 between the plurality of stress- relieving features 42, each of the plurality of stress-relieving features 42 being configured such that the deformable area 56 is movable relative to the planar area 58. In one aspect of the embodiment, each of the plurality of stress-relieving features 42 further has a planar central point 54 that is coplanar with the planar area 58. In one or more aspects of one or more examples of

embodiments, the first foil 38 is soldered to the first surface 34 of the substrate 32 at the planar central point 54 of each of the plurality of stress-relieving features 42.

[0044] In one or more aspects of one or more examples of embodiments, the first foil 38 is coated in a layer of positive active material 50 and the second foil 44 is coated in a layer of negative active material 52. In one or more aspects of one or more examples of embodiments, each of the at least one stress-relieving feature 42 has a height, the layer of positive active material 50 having a thickness that is at greater than the height In one or more aspects of one or more examples of embodiments, a foil 38 for a bipolar plate 26 for use in a bipolar battery 24 includes: at least one stress-relieving feature 42, the at least one stress-relieving feature 42 including a deformable area 56 and a planar central point 54. In one or more aspects of one or more examples of embodiments, the deformable area 56 surrounds the planar central point 54. In one or more aspects of one or more examples of embodiments, the deformable area 56 is an annular ridge. In one or more aspects of one or more examples of embodiments, the deformable area 56 is configured to be movable relative to the planar central point 54.

[0045] In one or more aspects of one or more examples of embodiments, the at least one stress-relieving feature 42 includes a plurality of stress-relieving features 42, the foil 38 further comprising: a first surface 46 and a second surface 48 opposite the first surface 46, the plurality of stress-relieving features 42 being on the first surface 46; and a planar area 58 on the first surface 46 of the foil 38 between the plurality of stress-relieving features 42, the planar central point 54 of each of the plurality of stress-relieving features 42 being coplanar with the planar area 58.

[0046] In one or more aspects of one or more examples of embodiments, a bipolar battery

24 includes: a housing 28; and at least one bipolar plate 26 within the housing 28, each of the at least one bipolar plate 26 including: a substrate 32 having a first surface 34 and a second surface 36 opposite the first surface 34; a first foil 38 affixed to the first surface 34 of the substrate 32, the first foil 38 including a plurality of stress-relieving features 42, each of the plurality of stress- relieving features 42 including a deformable area 56 and a planar central point 54, the first foil 38 being affixed to the first surface 34 of the substrate 32 at the planar central point 54 of each of the plurality of stress-relieving features 42, the deformable area 56 being movable relative to the planar central point 54 when the deformable area 56 is acted upon by a stress force; and a second foil 44 affixed to the second surface 36 of the substrate 32. In one or more aspects of one or more examples of embodiments, the first foil 38 is coated with a layer of positive active material 50 and the second foil 44 is coated with a layer of negative active material 52.

[0047] In one or more aspects of one or more examples of embodiments, the housing 28 includes a first end and a second end opposite the first end, the first foil 38 is a positive foil, and the second foil 44 is a negative foil. The bipolar battery 24 may further include, in one or more aspects of one or more examples of embodiments, a negative monopolar plate 30A at the first end of the housing 28, the negative monopolar plate 30A being proximate the positive foil 38, and a positive monopolar plate 30B at the second end of the housing 28, the positive monopolar plate 30B being proximate the negative foil 44.

[0048] It will be appreciated by persons skilled in the art that the present embodiments are not limited to what has been particularly shown and described herein above. In addition, unless mention was made above to the contrary, it should be noted that all of the accompanying drawings are not to scale. A variety of modifications and variations are possible in light of the above teachings.

[0049] Various advantages may be achieved by using the disclosed embodiments. For example, the disclosed may advantageously allow for stress reduction and prolonged life of the battery. In other words, while charging and discharging of a battery may cause stresses inside the battery, the disclosed may alleviate those stressors and prevent battery failure.

[0050] As utilized herein, the terms "approximately," "about," "substantially", and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the invention as recited in the appended claims.

[0051] It should be noted that references to relative positions (e.g., "top" and "bottom") in this description are merely used to identify various elements as are oriented in the Figures. It should be recognized that the orientation of particular components may vary greatly depending on the application in which they are used.

[0052] For the purpose of this disclosure, the term "coupled" means the joining of two members directly or indirectly to one another. Such joining may be stationary in nature or moveable in nature. Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another. Such joining may be permanent in nature or may be removable or releasable in nature.

[0053] It is also important to note that the construction and arrangement of the system, methods, and devices as shown in the various examples of embodiments is illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited. For example, elements shown as integrally formed may be constructed of multiple parts or elements show as multiple parts may be integrally formed, the operation of the interfaces may be reversed or otherwise varied, the length or width of the structures and/or members or connector or other elements of the system may be varied, the nature or number of adjustment positions provided between the elements may be varied (e.g. by variations in the number of engagement slots or size of the engagement slots or type of engagement). The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the various examples of embodiments without departing from the spirit or scope of the present inventions.

[0054] While this invention has been described in conjunction with the examples of embodiments outlined above, various alternatives, modifications, variations, improvements and/or substantial equivalents, whether known or that are or may be presently foreseen, may become apparent to those having at least ordinary skill in the art. Accordingly, the examples of embodiments of the invention, as set forth above, are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit or scope of the invention.

Therefore, the invention is intended to embrace all known or earlier developed alternatives, modifications, variations, improvements and/or substantial equivalents.

[0055] The technical effects and technical problems in the specification are exemplary and are not limiting. It should be noted that the embodiments described in the specification may have other technical effects and can solve other technical problems.

Claims

CLAIMS IN THE CLAIMS:

1. A bipolar plate comprising:

a substrate having a first surface and a second surface opposite the first surface; a first foil affixed to the first surface of the substrate; and

a second foil affixed to the second surface of the substrate,

the first foil including at least one stress-relieving feature having at least one deformable area.

2. The bipolar plate of claim 1, wherein a plurality of stress-relieving features are

symmetrically arranged on the first surface of the first foil.

3. The bipolar plate of claim 1, wherein the deformable area of each of the at least one stress- relieving feature is an annular ridge.

4. The bipolar plate of claim 3, wherein each of the at least one stress- relieving feature

includes a planar central point.

5. The bipolar plate of claim 4, wherein the first foil is affixed to the first surface of the

substrate at the planar central point of each of the at least one stress-relieving feature.

6. The bipolar plate of claim 4, wherein the first foil is soldered to the first surface of the substrate at the planar central point of each of the at least one stress-relieving feature.

7. The bipolar plate of claim 4, wherein the deformable area of each of the at least one stress- relieving feature is configured such that the deformable area is movable relative to the planar central point.

8. The bipolar plate of claim 1, wherein the at least one stress- relieving feature comprises a plurality of stress-relieving features, the first foil further including a planar area between the plurality of stress-relieving features, each of the plurality of stress- relieving features being configured such that the deformable area is movable relative to the planar area.

9. The bipolar plate of claim 8, wherein each of the plurality of stress- relieving features further has a planar central point that is coplanar with the planar area.

10. The bipolar plate of claim 1, wherein the first foil is coated in a layer of positive active material and the second foil is coated in a layer of negative active material.

11. The bipolar plate of claim 10, wherein each of the at least one stress- relieving feature has a height, the layer of positive active material having a thickness that is at greater than the height.

12. A foil for a bipolar plate for use in a bipolar battery, the foil comprising:

at least one stress-relieving feature, the at least one stress-relieving feature including a deformable area and a planar central point.

13. The foil of claim 12, wherein the deformable area surrounds the planar central point.

14. The foil of claim 12, wherein the deformable area is an annular ridge.

15. The foil of claim 12, wherein the deformable area is configured to be movable relative to the planar central point.

16. The foil of claim 15, wherein the at least one stress-relieving feature includes a plurality of stress-relieving features, the foil further comprising:

a first surface and a second surface opposite the first surface, the plurality of stress- relieving features being on the first surface; and a planar area on the first surface of the foil between the plurality of stress-relieving features, the planar central point of each of the plurality of stress-relieving features being coplanar with the planar area.

17. The foil of claim 16, wherein the at least one stress-relieving feature includes a plurality of stress-relieving features, the foil further comprising:

a first surface and a second surface opposite the first surface, the plurality of stress- relieving features being on the first surface; and

a planar area on the first surface of the foil between the plurality of stress-relieving features, the planar central point of each of the plurality of stress-relieving features being coplanar with the planar area.

18. A bipolar battery comprising: a housing; and

at least one bipolar plate within the housing comprising:

a substrate having a first surface and a second surface opposite the first surface; a first foil affixed to the first surface of the substrate, the first foil including a plurality of stress- relieving features, each of the plurality of stress-relieving features including a deformable area and a planar central point, the first foil being affixed to the first surface of the substrate at the planar central point of each of the plurality of stress-relieving features, the deformable area being movable relative to the planar central point when the deformable area is acted upon by a stress force; and

a second foil affixed to the second surface of the substrate.

19. The bipolar battery of claim 18, wherein the first foil is coated with a layer of positive active material and the second foil is coated with a layer of negative active material.

20. The bipolar battery of claim 18, wherein the housing includes a first end and a second end opposite the first end, the first foil is a positive foil, and the second foil is a negative foil, the bipolar battery further comprising: a negative monopolar plate at the first end of the housing, the negative monopolar plate being proximate the positive foil; and a positive monopolar plate at the second end of the housing, the positive monopolar plate being proximate the negative foil.