EXPANDABLE HOUSINGS FOR PRISMATIC AND CYLINDRICAL BATTERY CELLS

Abstract

A housing for a prismatic battery cell comprises first side faces, second side faces connected between the first side faces, a top face connected between the first and second side faces, and a bottom face connected between the first and second side faces. The first side faces, the second side faces, the top face, and the bottom face are designed to accommodate a battery cell stack. The second side faces, the top face, and the bottom face expand / contract to allow guided expansion / contraction of the housing in a first direction, while expansion in a second and third direction is limited perpendicular to the first direction.

Description

INTRODUCTION

[0001] The information provided in this section is intended to provide a general context for the disclosure. Work by the presently named inventors, to the extent described in this section, as well as aspects of the description that may not otherwise be considered prior art at the time of filing, are not expressly or impliedly admitted as prior art against this disclosure.

[0002] The present disclosure relates to battery cells and, more particularly, to a housing for prismatic and cylindrical battery cells.

[0003] Electric vehicles (EVs), such as battery electric vehicles (BEVs), hybrid vehicles, and / or fuel cell vehicles, comprise one or more electric machines and a battery system with one or more battery cells, modules, and / or packs. A power control system is used to control the charging and / or discharging of the battery system during charging and / or driving. SUMMARY

[0004] A housing for a prismatic battery cell comprises first side surfaces, second side surfaces connected between the first side surfaces, a top surface connected between the first side surfaces and the second side surfaces, and a bottom surface connected between the first side surfaces and the second side surfaces. The first side surfaces, the second side surfaces, the top surface, and the bottom surface are configured to receive a battery cell stack. The second side surfaces, the top surface, and the bottom surface expand / contract to allow guided expansion / contraction of the housing in a first direction while limiting expansion in second and third directions transverse to the first direction.

[0005] In other features, the second side surfaces, the top surface, and the bottom surface include ridges. The second side surfaces, the top surface, and the bottom surface of the housing are made of a first material that is less stiff than a second material of the first side surfaces. The second side surfaces, the top surface, and the bottom surface of the housing are made of a first material having a first thickness, wherein the first side surfaces are made of the first material and have a second thickness that is greater than the first thickness.

[0006] In other features, the second side surfaces, the top surface, and the bottom surface comprise first portions and second portions. The first portions are hardened or softened relative to the second portions by one of the following: The first portions of the second side surfaces, the top surface, and the bottom surface are hardened or softened by at least one of laser and infrared heating.

[0007] In other features, the first portions of the second side surfaces, the upper surface, and the lower surface are softened by ultrasonic vibration. The first side surfaces are one of inwardly and outwardly curved. The second side surfaces, the upper surface, and the lower surface include grooved areas and non-grooved areas, wherein the grooved areas are thinner than the non-grooved areas. One or more reinforcing beads are arranged on the first side surfaces.

[0008] In other features, an offset surface is arranged on the first side surfaces, wherein the offset surface comprises more than 50% of a surface area of ​​the first side surfaces. An offset surface is arranged on the first side surfaces. The offset surface comprises more than 50% of a surface area of ​​the first side surfaces.

[0009] A housing for a prismatic battery cell comprises first side surfaces, second side surfaces connected between the first side surfaces, a top surface connected between the first side surfaces and the second side surfaces, and a bottom surface connected between the first side surfaces and the second side surfaces. The housing is configured to receive a battery cell stack. The first side surfaces include at least one of a plurality of stiffening beads and an offset surface comprising more than 50% of the surface area of ​​the first side surfaces. The second side surfaces, the top surface, and the bottom surface expand to allow guided expansion / contraction of the housing in a first direction while limiting expansion in second and third directions transverse to the first direction.

[0010] In other features, the second side surfaces, the top surface, and the bottom surface include ridges. The second side surfaces, the top surface, and the bottom surface of the housing are made of a first material that is less stiff than a second material of the first side surfaces. The second side surfaces, the top surface, and the bottom surface of the housing are made of a first material having a first thickness, wherein the first side surfaces are made of the first material and have a second thickness that is greater than the first thickness.

[0011] In other features, the second side surfaces, the top surface, and the bottom surface comprise first portions and second portions. The first portions are hardened or softened using at least one of laser heating, infrared heating, and ultrasonic vibration relative to the second portions.

[0012] In other features, the first side surfaces are curved inwardly and outwardly. The second side surfaces, the upper surface, and the lower surface, include grooved areas and non-grooved areas, with the grooved areas being thinner than the non-grooved areas.

[0013] In other features, one or more reinforcing beads are arranged on the first side surfaces.

[0014] Further areas of applicability of the present disclosure will become apparent from the detailed description, claims, and drawings. The detailed description and specific examples are for illustrative purposes only and are not intended to limit the scope of the disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present disclosure will be more fully understood from the detailed description and the accompanying drawings, in which: Fig. 1 is a side cross-sectional view of an example of a battery cell having cathode electrodes, anode electrodes, and separators disposed within a battery cell casing according to the present disclosure; Fig. 2A to 2C are perspective and cross-sectional views illustrating an example of a housing for a prismatic battery cell with corrugated side surfaces according to the present disclosure; Fig. 3A to 3C are perspective and cross-sectional views illustrating an example of a casing for a prismatic battery cell with grooved side surfaces according to the present disclosure; Fig. 4A to 4C are perspective and cross-sectional views illustrating an example of a housing for a prismatic battery cell with laser softened and / or hardened side surfaces according to the present disclosure; Fig. 5A to 5C are perspective and cross-sectional views illustrating an example of a housing for a prismatic battery cell with weakened side surfaces according to the present disclosure; Fig. 6A to 6C are perspective and cross-sectional views illustrating an example of a housing for a prismatic battery cell with softened edges and / or corners according to the present disclosure; Fig. 7A to 7C are perspective and cross-sectional views illustrating an example of a housing for a prismatic battery cell with convex or inwardly curved side surfaces according to the present disclosure; Fig. 8A to 8C are perspective and cross-sectional views illustrating an example of a housing for a prismatic battery cell with offset side surfaces according to the present disclosure; Fig. 9A to 9C are perspective and cross-sectional views illustrating an example of a housing for a prismatic battery cell with stiffening beads according to the present disclosure; and Fig. 10 is a perspective view illustrating an example of a housing for a cylindrical battery cell having sides and / or a top surface including stiffening beads according to the present disclosure.

[0016] Reference numerals may be reused in the drawings to identify similar and / or identical elements. DETAILED DESCRIPTION

[0017] Although the enclosures are described in the context of battery cells for electric vehicles, the enclosures can also be used in stationary or other applications.

[0018] Charge / discharge cycles, battery cell aging, and / or battery cell malfunctions (such as overheating and / or thermal runaway) lead to changes in the volume and / or internal pressure of the battery cells. Current casings for prismatic and / or cylindrical cells experience bulging of the larger side surfaces in response to the increase in volume / pressure. This bulging can lead to uneven pressure distribution within the casing, which can result in uneven electrode wear and / or electrode detachment.

[0019] A housing for prismatic and / or cylindrical battery cells according to the present disclosure enables the guided expansion of an internal volume in response to cell expansion and / or increases in vent gas pressure by facilitating deformation in structurally rigid regions and / or limiting deformation in regions prone to bulging. Housings according to the present disclosure promote more uniform deformation and, consequently, a more uniform internal pressure distribution. A more uniform pressure distribution improves the battery's service life and / or electrical performance.

[0020] A housing for prismatic and / or cylindrical battery cells according to the present disclosure enables guided contraction of an internal volume upon application of external compressive forces, thereby facilitating uniform pressure application to the electrodes during the cell formation process.

[0021] Additionally, some of the housings support additional features (e.g., locking and / or arranging battery cells, cooling functions, etc.) for the housing. Although the present disclosure is illustrated using prismatic battery cells, the features may also be used for other battery cell formats, such as cylindrical or other types of battery cells.

[0022] The housings according to the present disclosure guide expansion due to battery cell swelling and / or an increase in vent gas pressure, or guide contraction upon application of external pressure in a predetermined manner to achieve uniform deformation and / or pressure distribution. In other words, the housings facilitate material expansion or compression in some predetermined directions while restricting material deformation in other directions and / or limiting local deformations. In one approach, structurally rigid areas are deliberately softened or weakened. For example, thinner material and / or less stiff material is strategically placed in some sections / locations of the housing. In other examples, some sections / locations of the housing (e.g., edges and / or corners of the housing) are strengthened or weakened using heat and / or ultrasonic vibration.Another approach involves stiffening areas that are prone to bulging (e.g., small or large sides of the case).

[0023] Referring to Fig. 1, a battery cell 10 includes C cathode electrodes 20, A anode electrodes 40, and S separators 32 arranged in a predetermined order in a battery cell stack 12 within a housing 50. The C cathode electrodes 20-1, 20-2, ..., and 20-C (where C is an integer greater than one) include active cathode layers 24 disposed on one or both sides of cathode current collectors 26. The A anode electrodes 40-1, 40-2, ..., and 40-A (where A is an integer greater than one) include active anode layers 42 disposed on one or both sides of the anode current collectors 46. In some examples, the current collectors are made of one or more materials selected from a group consisting of copper, stainless steel, brass, bronze, zinc, aluminum, and / or their alloys.In some examples, external tabs connected to the current collectors of the anode and cathode electrodes are located on opposite sides of the battery stack (as in . Fig. 1) or on the same side of the battery stack.

[0024] With reference now to Fig. 2A to 2C, a housing 100 for a prismatic battery cell includes first side surfaces 110, second side surfaces 112, a top surface 114, and a bottom surface 116. In this example, the first side surfaces 110 correspond to the surfaces with the largest surface area and are arranged parallel to an xy plane. The second side surfaces are arranged parallel to a yz plane. The top surface 114 and the bottom surface 116 are arranged parallel to an xz plane.

[0025] In this example, the top surface 114, the bottom surface 116, and the second side surfaces include corrugations 115. The corrugations 115 allow for accordion-like expansion or contraction in the z-axis direction to increase or decrease the overall length in the z-axis direction (e.g., within the same width of the housing 100 in the x- and y-axis directions).

[0026] When the battery cell swells and / or the internal gas pressure increases, the corrugations 115 along the second side surfaces 112, the top surface 114 and the bottom surface 116 flatten to allow expansion in the z-axis direction (compare Fig. 2B and Fig. 2C), which reduces the tendency of the large surfaces to bulge. The serrations 115 increase the rigidity of the side surfaces, preventing them from bulging in the y-axis direction.

[0027] When external pressure is applied to the housing, the corrugations 115 shorten along the second side surfaces 113, the upper surface 114 and the lower surface 116 to allow contraction in the z-axis direction.

[0028] In some examples, the housing 100 is made of metal. In some examples, the metal is selected from a group consisting of aluminum, aluminum alloys, steel, coated steel, stainless steel, high-strength steel, and / or combinations thereof. Some metals, such as aluminum alloys, are strengthened by heating, while other materials, such as high-strength steel, are weakened by heating. In some examples, the expansion of the housing during normal charging and / or discharging or the contraction of the housing during compression for cell formation does not exceed the elastic properties of the materials used for the housing 100. In other words, the expansion or contraction is reversible. However, major thermal events associated with battery cell malfunction may exceed the elasticity of the housing materials.

[0029] With reference now to Fig. 3A to 4C, the side surfaces of the housing are locally softened or hardened. Softening can be achieved by locally thinning the side surfaces to create a grooved structure through machining, laser ablation, or other processes. In other examples, the mechanical properties of the side surfaces can be locally modified and structured by laser softening / hardening without causing thickness changes. For example, a heat source such as a laser or an infrared emitter and / or local vibration such as ultrasonic vibration can be used.

[0030] In some examples, insulating layers and / or thermal interface materials are disposed between adjacent battery cells in a battery module and / or pack to contract and absorb all or part of the expansion. The insulating layers and / or thermal interface materials expand to fill the volume when the battery cells contract.

[0031] In Fig. 3A to 3C, a housing 200 for a prismatic battery cell includes first side surfaces 210, second side surfaces 212, a top surface 214, and a bottom surface 216. In this example, the top surface 214, the bottom surface 216, and the second side surfaces 212 include a plurality of grooves 215. The grooves 215 correspond to thinner locations disposed between thicker locations (e.g., at 217).

[0032] The plurality of grooves 215 enables accordion-like expansion or contraction in the z-axis direction (e.g., while simultaneously limiting expansion in the x- and y-axis directions). With increasing swelling and / or rising internal gas pressure, the plurality of grooves 215 expand in the z-axis direction (see Fig. 3B and Fig. 3C), thereby reducing uncontrolled bulging of the large surfaces. Upon application of external pressure, the plurality of grooves 215 shorten in the z-axis direction. The grooves 215 increase the rigidity of the second side surfaces 212, the top surface 214, and the bottom surface 216 to resist bulging or other undesirable non-uniform deformations in the x- and / or y-axis directions.

[0033] In Fig. 4A to 4C, a housing 300 for a prismatic battery cell includes first side surfaces 310, second side surfaces 312, a top surface 314, and a bottom surface 316. In this example, the top surface 314, the bottom surface 316, and the second side surface 312 include a plurality of sections 315 that have been softened by heating using a laser relative to a plurality of adjacent sections 317. When the plurality of sections 315 are softened by laser (generally without changing the material thickness), the plurality of sections 315 may expand more than the plurality of sections 317 (see, for example, Fig. 4B and Fig. 4C) or contract.

[0034] In other examples, the plurality of sections 315 are laser-hardened relative to the plurality of sections 317, and the plurality of sections 317 expand and contract as the bulging and / or internal pressure decreases. In some examples, the plurality of sections 315 and / or the plurality of sections 317 have a rectangular shape and extend from one side of the housing to the other side of the housing. In some examples, the plurality of sections 315 and the plurality of sections 317 alternate.

[0035] With reference now to Fig. 5A to 6C, the side surfaces are softened or weakened overall by using materials with a smaller thickness and / or lower strength, and / or the edges and / or corners are weakened by heat and / or vibration to allow for more uniform expansion / deformation. This allows the first side surfaces to lengthen or shorten in the z-axis direction (and suppresses buckling or other undesirable uneven deformation of the larger side surfaces).

[0036] In Fig. 5A to 5C, a housing 400 for a prismatic battery cell includes first side surfaces 410, second side surfaces 412, a top surface 414, and / or a bottom surface 416. In this example, the top surface 414, the bottom surface 416, and the second side surfaces 412 are weakened by using thinner material (compared to other portions of the housing) and / or using materials with lower overall strength. The top surface 414, the bottom surface 416, and / or the second side surfaces 412 allow expansion / contraction in the z-axis direction (while limiting expansion / contraction in the x- and y-axis directions). As the internal / external pressure increases, the top surface 414, the bottom surface 416, and / or the second side surfaces 412 deform in the z-axis direction (see FIG. Fig. 5B and Fig. 5C), thereby reducing the tendency for bulging or other undesirable uneven deformation of the large surfaces.

[0037] In Fig. 6A to 6C, a housing 500 for a prismatic battery cell includes first side surfaces 510, second side surfaces 512, a top surface 514, and a bottom surface 516. In this example, the edges 522 and / or corners 524 of the first side surfaces 510 (adjacent to the second side surfaces 512, the top surface 514, and the bottom surface 516) are softened. As the internal or external pressure increases, the edges 522 and corners 524 expand (see FIG. Fig. 6B and Fig. 6C) or contract in the z-axis direction, thereby reducing the tendency for bulging or other undesirable non-uniform deformation of the large surfaces.

[0038] With reference now to Fig. 7A to 7C, a housing includes an inwardly directed (or concave) curvature on the first side surfaces 610 to counteract the effect of bulging due to swelling and / or internal gas pressure. A housing 600 for a prismatic battery cell includes first side surfaces 610, second side surfaces 612, a top surface 614, and a bottom surface 616. In this example, the top surface 614, the bottom surface 616, and / or the second side surfaces 612 include corrugations 615. As described above and below, the corrugations 615 allow for accordion-like expansion in the z-axis direction while limiting expansion in the x- and y-axis directions. With increasing swelling and / or increasing internal pressure, the corrugations 615 flatten, and the curvature of the first side surfaces 610 straightens out in order to accommodate the expansion in the z-axis direction (cf. Fig. 2B and Fig. 2C), thereby reducing the tendency of the first side surfaces to bulge. The corrugations 615 increase the rigidity of the upper surface 614, the lower surface 616, and the second side surfaces 612 to counteract bulging in the x- and / or y-axis directions.

[0039] With reference now to Fig. 8A-9C, one or more stiffening features may be added to the first side surfaces (or the second side surface, the top surface, and / or the bottom surface) to counteract bulging. In some examples, the stiffening features include, but are not limited to, offset surfaces and / or stiffening beads. The stiffening features may be formed in a direction toward or away from the battery cell stack. The orientation of the stiffening beads may vary (e.g., the stiffening beads may be vertical, horizontal, or slanted). In combination with guided expansion / contraction features (such as ridges, weakened sections, grooves, etc.) on the second side surface, the top surface, and / or the bottom surface, the housing expands in a controlled manner without bulging the first side surface.

[0040] In Fig. 8A to 8C, a housing 700 for a prismatic battery cell includes first side surfaces 710, second side surfaces 712, a top surface 714, and a bottom surface 716. In this example, the first side surface 710 includes an offset surface 711. In this example, the offset surface 711 extends inwardly and encompasses more than 50% of the area of ​​the first side surfaces 710. The offset surface 711 increases the stiffness of the first side surface 710.

[0041] In Fig. 9A to 9C, a housing 800 for a prismatic battery cell includes first side surfaces 810, second side surfaces 812, a top surface 814, and a bottom surface 816. In this example, the first side surface 810 includes stiffening beads 811. The stiffening beads 811 extend in the x-axis direction, the y-axis direction, or both the x-axis and y-axis directions to stiffen the first side surface 810.

[0042] In Fig.10, a housing 900 for a cylindrical battery is shown having one or more stiffening features for stiffening the cylindrical side surfaces, the top surface, and / or the bottom surface. The housing 900 includes a side surface 910 defining an open cylinder, a top surface 914 enclosing one end of the open cylinder, and a bottom surface 916 enclosing an opposite end of the cylinder. In some examples, the side surface 910 includes one or more annular stiffening ridges 912 arranged parallel to the xz-plane and spaced apart in the y-axis plane. In some examples, the top surface 914 and the bottom surface 916 include annular ridges 915 arranged concentrically.

[0043] The foregoing description is merely illustrative and is in no way intended to limit the disclosure, its application, or uses. The broad teachings of the disclosure may be embodied in a variety of forms. While this disclosure contains particular examples, the true scope of the disclosure should not be considered so limited, since other modifications will become apparent upon a study of the drawings, the specification, and the following claims. It is understood that one or more steps within a method may be performed in different orders (or simultaneously) without departing from the spirit of the present disclosure.Although each of the embodiments described above includes certain features, one or more of these features described with respect to any embodiment of the disclosure may be implemented in any other embodiment and / or combined with features of any other embodiment, even if that combination is not explicitly described. In other words, the described embodiments are not mutually exclusive, and combinations of one or more embodiments remain within the scope of this disclosure.

[0044] Spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including "connected," "engaged," "coupled," "adjacent," "beside," "on," "over," "below," and "disposed." When a relationship between a first and a second element is not explicitly described as "direct" in the above disclosure, that relationship may be a direct relationship, with no other intervening elements present between the first and second elements, but may also be an indirect relationship, with one or more intervening elements (either spatial or functional) present between the first and second elements.As used herein, the phrase "A, B and / or C" should be construed as logical (A ORed with B ORed with C) using a non-exclusive logical OR, rather than as "at least one of A, at least one of B and at least one of C."

[0045] In the figures, the direction of an arrow, as indicated by the arrowhead, generally indicates the flow of information (such as data or instructions) of interest for the illustration. For example, if element A and element B exchange a lot of information, but the information communicated from element A to element B is relevant for the illustration, the arrow may point from element A to element B. This unidirectional arrow does not imply that no other information is communicated from element B to element A. Further, when communicating information from element A to element B, element B may send requests or acknowledgments for the information to element A.

Claims

[1] Housing for a prismatic battery cell, comprising: first side surfaces; second side surfaces connected between the first side surfaces; an upper surface connected between the first side surfaces and the second side surfaces; and a lower surface connected between the first side surfaces and the second side surfaces, wherein the first side surfaces, the second side surfaces, the upper surface and the lower surface are configured to receive a battery cell stack, and wherein the second side surfaces, the top surface and the bottom surface expand / contract to allow guided expansion / contraction of the housing in a first direction while limiting expansion in second and third directions transverse to the first direction. [2] The housing of claim 1, wherein the second side surfaces, the top surface and the bottom surface comprise corrugations. [3] The housing of claim 1, wherein the second side surfaces, the top surface and the bottom surface of the housing are made of a first material that is less stiff than a second material of the first side surfaces. [4] The housing of claim 1, wherein the second side surfaces, the top surface and the bottom surface of the housing are made of a first material having a first thickness, the first side surfaces being made of the first material and having a second thickness that is greater than the first thickness. [5] Housing according to claim 1, wherein: the second side surfaces, the upper surface and the lower surface comprise first sections and second sections, and the first sections are hardened or softened relative to the second sections of one of. [6] The housing of claim 5, wherein the first portions of the second side surfaces, the top surface, and the bottom surface are hardened or softened by at least one of laser and infrared heating. [7] The housing of claim 5, wherein the first portions of the second side surfaces, the upper surface and the lower surface are softened by ultrasonic vibration. [8] A housing according to claim 2, wherein the first side surfaces are curved one of inwardly and outwardly. [9] Housing according to claim 1, wherein: the second side surfaces, the upper surface and the lower surface comprise grooved areas and non-grooved areas, the grooved areas being thinner than the non-grooved areas. [10] The housing of claim 1, further comprising one or more reinforcing beads disposed on the first side surfaces.

Images