BATTERY CELL WITH INTERNAL STACK EXPANSION CONTROL MECHANISM

Abstract

A battery cell comprises a cell container having a bottom and a plurality of sidewalls connected to the bottom, the bottom and the plurality of sidewalls defining a cell stack receiving zone. A battery cell stack disposed in the battery stack receiving zone. A resilient expansion limiter is disposed on one of the plurality of sidewalls in the cell stack receiving zone. The resilient expansion limiter controls the expansion of the battery cell stack.

Description

INTRODUCTION

[0001] The subject matter of the disclosure relates to the technology of battery assemblies and, in particular, to a battery cell having an internal stack expansion control mechanism.

[0002] Battery assemblies are formed from a plurality of battery cells. Battery cells comprise electrode stacks arranged within a casing. Charging and discharging of the battery cells causes the stack to expand over time. As the stacks expand, pressure is exerted on the casing's interior wall surfaces. Furthermore, the expansion reduces open spaces within the casing that hold electrolyte. The pressure on the casing and the additional pressure on the electrolyte resulting from a reduction in casing volume can impair battery performance. Accordingly, it is desirable to provide a system for controlling battery stack expansion. SUMMARY

[0003] A battery cell according to one non-limiting example comprises a cell container having a bottom and a plurality of sidewalls connected to the bottom, the bottom and the plurality of sidewalls defining a cell stack receiving zone. A battery cell stack is disposed in the battery stack receiving zone. A resilient expansion limiter is disposed on one of the plurality of sidewalls in the cell stack receiving zone. The resilient expansion limiter controls the expansion of the battery cell stack.

[0004] In addition to one or more of the features described herein, the plurality of sidewalls includes a first sidewall, a second sidewall spaced from the first sidewall, a third sidewall, and a fourth sidewall spaced from the third sidewall, the third sidewall and the fourth sidewall extending between and interconnecting the first sidewall and the second sidewall, the resilient expansion limiter being attached to one of the first and second sidewalls.

[0005] In addition to one or more of the features described herein, the first sidewall comprises a first region and the third sidewall comprises a second region, the first region being larger than the second region.

[0006] In addition to one or more of the features described herein, the elastic expansion limiter includes a first surface attached to one of the first and second side walls and a second surface opposite the first surface.

[0007] In addition to one or more of the features described in this document, the second surface is a substantially planar surface.

[0008] In addition to one or more of the features described in this document, the second surface is a curved surface.

[0009] In addition to one or more of the features described herein, the elastic expansion limiter comprises a plurality of spring elements disposed between the first surface and the second surface.

[0010] In addition to one or more of the features described herein, the elastic expansion limiter comprises a first elastic expansion limiter attached to the first surface and a second elastic expansion limiter attached to the second surface.

[0011] In addition to one or more of the features described herein, a pressure pad is disposed between the elastic expansion limiter and the one of the plurality of side walls.

[0012] In addition to one or more of the features described in this document, the elastic expansion limiter comprises a honeycomb structure.

[0013] A vehicle according to one non-limiting example includes a body having a passenger compartment, a plurality of wheels connected to the body, and a drive unit supported within the body. The drive unit is connected to at least one of the plurality of wheels. A battery assembly is supported by the body and is electrically connected to the drive unit. The battery assembly includes a plurality of battery cells. Each of the plurality of battery cells includes a cell container having a floor, a plurality of sidewalls connected to the floor, the floor and the plurality of sidewalls defining a cell stack receiving zone. A battery cell stack is disposed in the battery stack receiving zone. A resilient expansion limiter is disposed on one of the plurality of sidewalls in the cell stack receiving zone.The elastic expansion limiter controls the expansion of the battery cell stack.

[0014] In addition to one or more of the features described herein, the plurality of sidewalls includes a first sidewall, a second sidewall spaced from the first sidewall, a third sidewall, and a fourth sidewall spaced from the third sidewall, the third sidewall and the fourth sidewall extending between and interconnecting the first sidewall and the second sidewall, the resilient expansion limiter being attached to one of the first and second sidewalls.

[0015] In addition to one or more of the features described herein, the first sidewall comprises a first region and the third sidewall comprises a second region, the first region being larger than the second region.

[0016] In addition to one or more of the features described herein, the elastic expansion limiter includes a first surface attached to one of the first and second side walls and a second surface opposite the first surface.

[0017] In addition to one or more of the features described in this document, the second surface is a substantially planar surface.

[0018] In addition to one or more of the features described in this document, the second surface is a curved surface.

[0019] In addition to one or more of the features described herein, the elastic expansion limiter comprises a plurality of spring elements disposed between the first surface and the second surface.

[0020] In addition to one or more of the features described herein, the elastic expansion limiter comprises a first elastic expansion limiter attached to the first surface and a second elastic expansion limiter attached to the second surface.

[0021] In addition to one or more of the features described herein, a pressure pad is disposed between the elastic expansion limiter and the one of the plurality of side walls.

[0022] In addition to one or more of the features described in this document, the elastic expansion limiter comprises a honeycomb structure.

[0023] The above features and advantages, as well as other features and advantages of the disclosure, will be readily apparent from the following detailed description when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Further features, advantages and details are included by way of example only in the following detailed description, which refers to the drawings in which: Fig. 1 is a left side view of a vehicle including a battery assembly with battery cells provided with an internal stack expansion control mechanism, according to a non-limiting example; Fig. 2 is an exploded view of the battery assembly with battery cells provided with an internal stack expansion control mechanism, according to a non-limiting example; Fig. 3 is a partial perspective view of battery cells provided with an internal stack expansion control mechanism, according to a non-limiting example; Fig. 4 an exploded perspective view of one of the battery cells of Fig. 3 according to a non-limiting example; Fig. 5 a cross-sectional view of the battery cell from above along line 5-5 of Fig. 4 is; Fig. 6 is a top cross-sectional view of a battery cell provided with an internal stack expansion control mechanism, according to another non-limiting example; Fig. 7 is an exploded perspective view of one of the battery cells of Fig. 3 according to a further non-limiting example; Fig. 8 a cross-sectional view of the battery cell from above along line 8-8 of Fig. 7 is; Fig. 9 is a top cross-sectional view of a battery cell according to another non-limiting example; Fig. 10 is a top cross-sectional view of a battery cell provided with an internal stack expansion control mechanism and a pressure pad, according to another non-limiting example; Fig. 11 is a top cross-sectional view of a battery cell provided with an internal stack expansion control mechanism and a pressure pad, according to another non-limiting example; Fig. 12 is a top cross-sectional view of a battery cell provided with an internal stack expansion control mechanism and a pressure pad, according to yet another non-limiting example; and Fig. 13 is a top cross-sectional view of a battery cell provided with an internal stack expansion control mechanism and a pressure pad, according to yet another non-limiting example. DETAILED DESCRIPTION

[0025] The following description is merely exemplary and is not intended to limit the present disclosure, its application, or uses. It should be understood that throughout the drawings, corresponding reference characters designate like or corresponding parts and features.

[0026] A vehicle according to a non-limiting example is in Fig. 1, generally designated 10. The vehicle 10 includes a body 12 supported on a plurality of wheels 16. The body 12 partially defines a passenger compartment 20 having seats disposed behind an instrument panel 26. A steering controller 30 is disposed between the seats 23 and the instrument panel 26. The steering controller 30 is actuated to control the orientation of selected ones of the plurality of wheels 16. The vehicle 10 includes an electric drive unit 34 that drives one or more of the plurality of wheels 16.

[0027] A rechargeable energy storage system (RESS) or battery assembly 38 is disposed within the housing 12 and provides power to the electric drive unit 34. In other arrangements, a fuel cell (not shown) may be used to power the electric drive unit 34. It should be noted that the position of the electric drive unit 34 and the battery assembly 38 may vary. As shown in Fig. 2, the battery assembly 38 includes a housing 50 having a base member 52, an outer cover 54, and a number of inner covers 56. The inner covers 56 shield a plurality of battery cells 60 arranged in a number of adjacent rows 62, as shown in Fig. 3 shown.

[0028] It will now Fig. 4 to describe one of the plurality of battery cells 60, it being understood that the remaining ones of the plurality of battery cells 60 may comprise a similar structure. The battery cell 60 includes a cell container 70 having a bottom 72, a plurality of sidewalls 76, and a top wall 78. The top wall 78 supports a pair of electrodes 80 including a cathode 82 and an anode 84. The bottom 72, the plurality of sidewalls 76, and the top wall 78 form a cell stack receiving zone 86.

[0029] The plurality of sidewalls 76 includes a first sidewall 88, a second sidewall 90 disposed opposite the first sidewall 88, a third sidewall 92, and a fourth sidewall 94 disposed opposite the third sidewall 92. The third sidewall 92 and the fourth sidewall 94 extend between and are connected to the first sidewall 88 and the second sidewall 90. In one non-limiting example, the first sidewall 88 and the second sidewall 90 comprise a first region, and the third sidewall 92 and the fourth sidewall 94 comprise a second region that is smaller than the first region. As shown in Fig. 5, a cell stack 100 is disposed in the cell stack receiving zone 86 between the first side wall 88 and the second side wall 90 and the third side wall 92 and the fourth side wall 94.

[0030] Reference is now made to Fig. 5 and continue on Fig. 4 to describe the cell container 70 according to a non-limiting example. The first sidewall 88 includes a first inner surface 102, and the second sidewall 90 includes a second inner surface 104 opposite the first inner surface 102. The cell container 70 includes a first elastic expansion limiter 108 and a second elastic expansion limiter 110 that restrict and limit the outward expansion of the cell stack 100. Reference will now be made to Fig. 5 to describe the first elastic expansion limiter 108, with the understanding that the second elastic expansion limiter 110 includes a similar structure. Although the cell 70 is illustrated with two expansion limiters, it may be provided with a single expansion limiter or with more than two expansion limiters, depending on design requirements.

[0031] In one non-limiting example, the first elastic expansion limiter 108 includes a first surface 112 and an opposing second surface 114, between which an elastic expansion medium 116 is defined. The first surface 112 is attached to the first inner surface 102 of the first sidewall 88. The first surface 112 may be attached using a variety of techniques, including gluing, welding, soldering, overmolding, and the like, depending on the material used to form the elastic expansion medium 116. In one non-limiting example, the first surface 112 may define a first side (not separately labeled) of the elastic expansion medium 116, and the second surface 114 may define a second side (also not separately labeled) of the elastic expansion medium 116.

[0032] In one non-limiting example, the first elastic expansion medium 116 is a honeycomb element formed from an elastic material such as metal, including aluminum, steel, and various alloys and composites, including polymer composites, that are non-reactive with electrolyte yet have elasticity to accommodate expansions of the cell stack. The first elastic expansion limiter 108 and the second elastic expansion limiter 110, rather than being formed from an elastic material, may comprise spring elements, as shown at 128 in Fig. 6, disposed between the first surface 112 and the second surface 114. Regardless of the material used, the first elastic expansion limiter 108 and the second elastic expansion limiter 110 are designed to expand and contract with the cell stack 100 without increasing the pressure on the first sidewall 88 and the second sidewall 90 in a manner that would result in a change in the external dimensions of the cell container 70.

[0033] It will now Fig. 7, Fig. 8 and Fig. 9 to describe a first elastic expansion limiter 144 and a second elastic expansion limiter 146 according to another non-limiting example. Since the first elastic expansion limiter 144 and the second elastic expansion limiter 146 are substantially similarly shaped, a detailed description will follow relating to the first elastic expansion limiter 144. In one non-limiting example, the first elastic expansion limiter 144 includes a first surface 152 and a second surface 154, between which an elastic expansion medium 156 is defined. The first surface 152 is substantially planar and may be attached to the first surface 102 using a variety of techniques, including gluing, welding, soldering, overmolding, and the like, depending on the material used to form the elastic expansion medium 156.

[0034] In one non-limiting example, the second surface 154 is a wavy or curved surface 158 having peaks 160 and valleys 162. The wavy or curved surface 158 may define a ridged surface 158. Also in a similar manner as described herein, the first surface 152 may define a first side (not separately labeled) of the elastic expansion medium 156, and the second surface 154 may define a second side (also not separately labeled) of the elastic expansion medium 156.

[0035] In one non-limiting example, the elastic expansion medium 156 is a honeycomb element formed from an elastic material such as metal, including aluminum, steel, and various alloys and composites, including polymer composites, that are non-reactive with electrolyte yet have elasticity to absorb cell stack expansion. The first elastic expansion limiter 144 and the second elastic expansion limiter 146, rather than being formed from an elastic material, may comprise spring elements, as shown at 180 in Fig. 9. Regardless of the material used, the first elastic expansion limiter 144 and the second elastic expansion limiter 146 are designed to expand and contract with the cell stack 100 without increasing the pressure on the first sidewall 88 and the second sidewall 90 in a manner that would result in a change in the external dimensions of the cell container 70.

[0036] It will now Fig. 10, Fig. 11, Fig. 12 and Fig. 13 to describe a battery cell 60 according to further non-limiting examples. Referring to Fig. 10, the battery cell 60 includes, in addition to the first elastic expansion limiter 108 and the second elastic expansion limiter 110, a first compression pad 180 and a second compression pad 182. The first compression pad 180 is disposed between the first elastic expansion limiter 108 and the inner surface 102 of the first wall 88, and the second compression pad 182 is disposed between the second elastic expansion limiter 110 and the second inner surface 104 of the second sidewall 90. The first compression pad 180 and the second compression pad 188 provide additional expansion absorption characteristics for the cell stack 100.

[0037] Referring to Fig. 11, the battery cell 60 includes, in addition to the first pressure pad 180 and the second pressure pad 182, a third pressure pad 190 and a fourth pressure pad 192. The third pressure pad 190 is disposed between the first elastic expansion limiter 108 and the cell stack 100, and the fourth pressure pad 192 is disposed between the cell stack 100 and the second elastic expansion limiter 110. In one non-limiting example, the first pressure pad 180, the second pressure pad 182, the third pressure pad 190, and / or the fourth pressure pad 192 may be formed from a variety of materials capable of withstanding contact with an electrolyte. In one non-limiting example, the material may be a purpose-built material capable of accommodating not only dimensional changes of the cell stack 100 but also volumetric changes of the electrolyte.

[0038] In addition to adapting to volume changes, one or more of the first pressure pad 180, second pressure pad 182, third pressure pad 190, and / or fourth pressure pad 192 may include a heat-resistant coating that reduces temperatures on external surfaces of the cell container 70. For example, the second pressure pad 182 may include a thermal barrier layer 200, as shown in Fig. 12 and Fig. 13. In addition, although the pressure pads are shown as a complement to the elastic expansion limiters, they can also be used alone.

[0039] The terms "a" and "an" do not imply a limitation of quantity, but denote the presence of at least one of the stated elements. The term "or" means "and / or" unless the context clearly indicates otherwise. When reference is made throughout this specification to "an aspect," this means that a particular element (e.g., a feature, structure, step, or property) described in connection with the aspect is included in at least one of the aspects described in this specification and may or may not be present in other aspects. It is understood that the described elements in the various aspects may be combined in any suitable manner.

[0040] When an element such as a layer, film, region, or substrate is described as lying "on" another element, it may lie directly on top of the other element, or there may be intervening elements. In contrast, when an element is described as lying "directly on" another element, there are no intervening elements.

[0041] Unless otherwise indicated herein, all examination standards are the most recent standard in force on the filing date of this application or, if priority is claimed, on the filing date of the earliest priority application in which the examination standard appears.

[0042] Unless otherwise defined, technical and scientific terms used in this document have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0043] Although the above disclosure has been described with reference to exemplary embodiments, those skilled in the art will understand that various changes may be made and equivalent elements may be substituted without departing from the scope thereof. Furthermore, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from its essential scope. Therefore, it is intended that the present disclosure not be limited to the particular embodiments disclosed, but will include all embodiments falling within its scope.

Claims

[1] Battery cell, comprising: a cell container having a bottom, a plurality of side walls connected to the bottom, the bottom and the plurality of side walls defining a cell stack receiving zone; a battery cell stack arranged in the cell stack receiving zone; and an elastic expansion limiter disposed on one of the plurality of sidewalls in the cell stack receiving zone, the elastic expansion limiter controlling the expansion of the battery cell stack. [2] The battery cell of claim 1, wherein the plurality of sidewalls includes a first sidewall, a second sidewall spaced from the first sidewall, a third sidewall, and a fourth sidewall spaced from the third sidewall, the third sidewall and the fourth sidewall extending between and interconnecting the first sidewall and the second sidewall, the elastic expansion limiter being attached to one of the first and second sidewalls. [3] The battery cell of claim 2, wherein the first sidewall comprises a first region and the third sidewall comprises a second region, the first region being larger than the second region. [4] The battery cell of claim 2, wherein the elastic expansion limiter comprises a first surface attached to one of the first and second side walls and a second surface opposite the first surface. [5] The battery cell of claim 4, wherein the second surface is a substantially planar surface. [6] The battery cell of claim 4, wherein the second surface is a curved surface. [7] The battery cell of claim 2, wherein the elastic expansion limiter comprises a first elastic expansion limiter attached to the first side wall and a second elastic expansion limiter attached to the second side wall. [8] The battery cell of claim 1, further comprising a pressure pad disposed between the elastic expansion limiter and the one of the plurality of side walls. [9] The battery cell of claim 1, wherein the elastic expansion limiter comprises a honeycomb structure. [10] Vehicle comprising: a body with a passenger cell; a plurality of wheels connected to the body; a drive unit mounted in the body, the drive unit being connected to at least one of the plurality of wheels; and a battery assembly supported by the body and electrically connected to the drive unit, the battery assembly comprising a battery cell according to claim 1.

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