Battery cell with electrode stack support designed to allow gas flow

Abstract

A battery cell comprising: a housing; a stack of anode electrodes and cathode electrodes within the housing; a vent configured to open to allow gas to escape from within the housing when pressure within the housing exceeds a threshold; and a support within the housing supporting the stack, the support defining at least one passageway through the support configured to allow gas to flow through the support to the vent.

Description

INTRODUCTION

[0001] The present invention relates to a battery cell according to the preamble of claim 1, as is essentially known from CN 2 18 602 675 U.

[0002] Essentially comparable battery cells are disclosed in the documents CN 1 16 544 488 A, US 2015 / 0 295 217 A1, US 2021 / 0 305 655 A1 and US 2023 / 0 018 297 A1.

[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. Each battery includes electrodes with current collectors coated with an active material. A power control system is used to control the charging and / or discharging of the battery system during charging and / or driving. SUMMARY

[0004] According to the invention, a battery cell is presented which is characterized by the features of claim 1.

[0005] In other features, the battery cell is designed as a prismatic cell.

[0006] In further features, the bracket is a first bracket, the battery cell further comprising a second bracket; and the first bracket and the second bracket are located on opposite sides of the vent.

[0007] In further features, the holder includes an upper end in contact with the stack, a lower end in contact with a bottom surface of the housing, and an intermediate surface extending between the upper and lower ends.

[0008] In further features, the intermediate surface extends at an acute angle to the bottom surface of the housing.

[0009] The present invention further provides, in various features, a battery cell comprising: a prismatic housing; a stack of anode electrodes and cathode electrodes within the prismatic housing; a vent opening on a bottom surface of the prismatic housing, the vent opening configured to open to allow gas to escape from within the prismatic housing when pressure within the prismatic housing exceeds a threshold; and at least one support within the prismatic housing supporting the stack, the at least one support resting on the bottom surface of the prismatic housing and defining passageways on opposite sides of the vent opening to allow gas to flow through the at least one support to the vent opening.

[0010] In further features, an insulating material is located between the stack and the at least one holder.

[0011] Further areas of applicability of the present invention will become apparent from the detailed description, claims, and drawings. The detailed description and specific examples are provided for illustrative purposes only. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present invention 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 exemplary battery cell having an electrode stack supported within a housing by retainers according to the present invention; Fig. 2A is another cross-sectional view of the exemplary battery cell with brackets according to the present invention configured to support the electrode stack; Fig. 2B a floor area of Fig. 2A illustrates; Fig. 2C is a side view of an exemplary holder according to the present invention configured to support the electrode stack; Fig. Figure 2D is a side view of another holder according to the present invention configured to support the electrode stack; Fig. 2E is a side view of another holder according to the present invention configured to support the electrode stack; Fig. Figure 2F is yet another support according to the present invention configured to support the electrode stack; Fig. 3A is a cross-sectional view of a bottom portion of the exemplary battery cell with another exemplary support according to the present invention configured to support the electrode stack; Fig. 3B a side view of the bracket of Fig. 3A is; Fig. 3C a bottom view of the bracket of Fig. 3A is; Fig. 4A is a cross-sectional view of a bottom portion of the exemplary battery cell with further exemplary supports according to the present invention configured to support the electrode stack; Fig. 4B is a bottom view of the brackets of Fig. 4A is; Fig. 5A, Fig. 5B and Fig. 5C are side views of further exemplary supports configured to support the electrode stack, wherein the supports are each configured to be foldable, as in Fig. 6 and Fig. 7 illustrates; Fig. 6 a cross-sectional view of a bottom portion of the exemplary battery cell with the holder of Fig. 5A, which is corrugated folded according to the present invention to support the electrode stack; and Fig. 7 a cross-sectional view of a bottom portion of the exemplary battery cell with the holder of Fig. 5A, which is folded at a right angle to support the electrode stack according to the present invention.

[0013] Reference numerals may be reused in the drawings to identify similar and / or identical elements. DETAILED DESCRIPTION

[0014] The present invention encompasses various fixtures configured to support an electrode stack within a battery cell casing. The present invention relates to any suitable battery cell, such as, but not limited to, prismatic can cells, including tall can cells. The fixtures form passages through which gas can flow to relieve pressure within the battery cell, such as during a thermal runaway. Gas released during a thermal runaway can flow through the fixtures to a vent through which the gas is released once the gas pressure within the casing exceeds a threshold. The present invention is configured for use with tall prismatic cells having a bottom vent and any other suitable battery cell configuration having a passage for gas flow.

[0015] Fig. 1 illustrates an exemplary battery cell 10 configured to include a holder according to the present invention, wherein the holder is configured to support a battery electrode stack. The battery cell 10 may be configured for use in any suitable application, such as any suitable automotive or non-automotive application. The battery cell 10 includes C cathode electrodes 20, A anode electrodes 40, and S separators 32 arranged in a predetermined order in a stack 12 that rests within a housing 50. C, A, and S are integers each greater than one. In some examples, A = C+1. The C cathode electrodes 20-1, 20-2, ..., and 20-C include cathode active layers 24 disposed on one or both sides of cathode current collectors 26. The anode electrodes 40-1, 40-2, ...and 40-A include anode active layers 42 disposed on one or both sides of the anode current collectors 46.

[0016] Fig. 2A illustrates further features of the battery cell 10. In the example of Fig. 2A, the battery cell 10 is configured as a tall prismatic cell. The housing 50 may have a rectangular cross-section or a cross-section with any other suitable shape. The cathode current collectors 26 and / or the anode current collectors 46 include external connecting tabs 60 and 62, respectively, which are laser-welded to internal terminals 64 and 66 and in contact with external terminals 70 and 72 of the battery cell 10.

[0017] The housing 50 includes a vent 80. The vent 80 is configured to open to relieve pressure within the housing 50, such as during thermal runaway. For example, in the event of a thermal runaway, gases may escape from the stack 12. Fig. 2A includes arrows 82 illustrating an exemplary gas flow during a thermal runaway event. The vent 80 is configured to open to allow gas to escape from the interior of the housing 50 when the pressure of the gas within the housing 50 exceeds a predetermined threshold. In the illustrated example, the vent 80 is located on the bottom surface 90 of the housing 50 opposite the tabs 60 and 62 located on the top of the housing 50. The vent 80 may also be located at any other suitable location on the housing 50.

[0018] The stack 12 is supported within the housing 50 by one or more battery electrode stack supports. In the illustrated examples, the supports rest on the bottom surface 90. The supports may also be disposed at any other suitable locations on the housing 50. As explained herein, the supports define passageways configured to allow gas released from the stack 12 to flow through the supports, such as to the vent opening 80 on the bottom surface 90 or to any suitable location throughout the housing 50.

[0019] The supports may be in direct or indirect contact with the stack 12. For example, an insulating film 92 may be arranged between the stack 12 and the supports, as shown in Fig. 2B. The insulating film 92 may be any suitable insulating material, such as any suitable foil or layer. The insulating film 92 is configured to reduce stress concentration at the supports and / or provide additional insulation between the supports and the stack 12 when the supports are made of metal.

[0020] Fig. 2A, Fig. 2B and Fig. 2C illustrate an exemplary support 110A in accordance with the present invention. The support 110A is configured to support the stack 12 within the housing and to allow gases released from the stack 12 during a thermal runaway to flow through the support 110A to the vent 80. Fig. 2A and Fig. 2B shows two of the brackets 110A spaced apart on opposite sides of the lower vent opening 80. The battery cell 10 may include any other suitable number of brackets 110A, such as one, three, or more.

[0021] Each of the supports 110A is generally shaped like a coil or spring. The supports 110A define many passages between the coils to allow gas to flow through the supports 110A. The supports 110A are generally not flexible, but may be flexible depending on the application. In the example of Fig. 2C, the support 110A includes an upper end 112A and a lower end 114A, both of which have the same or substantially the same diameter. The coils 116A form the passages through which the gas flows through the support 110A. In addition, the support 110A of Fig. 2C, a uniform spacing (a uniform pitch) between the spirals 116A along the length of the support 110A. The support 110A may be dimensioned and shaped in any other suitable manner.

[0022] For example and as in Fig. 2D, the holder 110A may have a spiral pitch in the upper half that is relatively larger than the spiral pitch in the lower half. In the example of Fig. 2E, a spiral pitch in the upper half can be relatively smaller than a spiral pitch in the lower half. In the example of Fig. 2F, the diameter at the lower end 114A may be larger than the diameter at the upper end 112A. In another example, each spiral 116A of the support 110A may have a different pitch, such that adjacent spirals 116A have different pitches. The support 110A may also be configured so that groups of spirals 116A have different pitches, with each spiral 116A of a particular group having the same pitch. The support 110A may also include any other suitable pitch and diameter dimensions.

[0023] Fig. 3A, Fig. 3B and Fig. 3C illustrate another support 110B according to the present invention for supporting the stack 12 within the housing 50. The support 110B includes a generally planar support 130B. Extending from the support 130B are a plurality of legs 132B. The legs 132B stand on the bottom surface 90 of the housing 50. With particular reference to Fig. 3C, the legs 132B are spaced apart and offset from each other to form passageways configured to allow gas released from the stack 12, such as during a thermal runaway, to flow between the legs 132B to the vent opening 80. The support 130B defines a passageway in the form of an opening 134B at its center to allow gas released from a bottom of the stack 12 to flow through the support 130B to the lower vent opening 80. The opening 134B may have any suitable shape, such as oval, round, rectangular, square, etc.

[0024] Fig. 4A and Fig. 4B illustrate a pair of supports 110C according to the present invention for supporting the stack 12. The supports 110C each include a generally planar beam 130C. Legs 132C extend from each beam 130C. The legs 132C are spaced apart and offset from one another to form passageways configured to allow gas released from the stack 12, such as during a thermal runaway, to flow between the legs 132C to the vent opening 80. The two supports 110C are spaced apart on the bottom surface 90 on opposite sides of the stack 12 to allow gas escaping from the stack 12 to flow unobstructed to the vent opening 80.

[0025] Fig. 5A, Fig. 5B and Fig. 5C illustrate further supports 110D, 110E, and 110F for supporting the stack 12 within the housing 50, which supports are configured to allow gas released from the stack 12 to flow through the supports 110D, 110E, and 110F to the vent opening 80. The support 110D according to the invention includes a carrier 130D defining a passageway in the form of an opening 140D at a center or generally at a center of the carrier 130D. The opening 140D may be oval, as shown, or have any other suitable shape. The support 110E includes a carrier 130E that, contrary to the invention, defines a plurality of passageways in the form of openings 140E staggered around the carrier 130E. The openings 140E may be oval, as shown, or have any other suitable shape.The holder 110F comprises a support 130F which, contrary to the invention, defines a plurality of passages in the form of openings 140F, which may be rectangular as illustrated or have any other suitable shape.

[0026] To space the stack 12 from the bottom surface 90 of the housing 50, the supports 130D, 130E, 130F are folded one or more times at any angle, such as an angle less than 90°, greater than 90°, or at a 90° angle. The folded supports 130D, 130E, 130F are then placed on the bottom surface 90 to support the stack 12. The gas released from the stack 12 can flow through the openings 140D, 140E, 140F through the supports 110D, 110E, 110F to the vent opening 80.

[0027] Fig. 6 illustrates two of the supports 110D spaced on opposite sides of the vent opening 80 and folded to have a wave-like or sawtooth-like shape when viewed from a long side of a rectangular prismatic battery cell 10. For example, an upper end 112D contacts the stack 12, a lower end 114D contacts the bottom surface 90, and an intermediate surface 118D extends therebetween at an acute angle relative to the bottom surface 90.

[0028] Fig. Figure 7 illustrates two of the holders 110D which, contrary to the invention, are folded to have a columnar shape when viewed from a long side of a rectangular prismatic battery cell 10. In the example of Fig. 7, the intermediate surface 118D extends at a right angle to the upper end 112D and the lower end 114D and at a right angle to the bottom surface 90. The brackets 110E and 110F can be Fig. 6 and Fig. 7 can be folded and arranged in a similar manner. Thus, the bracket 110D can be Fig. 6 can be replaced by the bracket 110E or 110F. And in Fig. 7, the bracket 110D can be replaced by the bracket 110E or 110F. Regardless of whether the brackets 110D, 110E, 110F are used as in Fig. 6 and Fig. 7 or folded in any other suitable manner, the openings 140D, 140E, 140F provide passageways configured to allow gas released from the stack 12 to flow through the supports 110D, 110E, 110F to the vent opening 80, for example, during a thermal runaway.

[0029] Each of the brackets 110A, 110B, 110C, 110D, 110E, 110F may be made from any suitable material, such as any suitable polymeric material, metallic material, polymer-coated metals, carbon fiber composite, etc. Examples of polymeric materials include, but are not limited to: polytetrafluoroethylene (PTFE), polyethylene (PE), polypropylene (PP), etc. Examples of metallic materials include, but are not limited to: stainless steel, copper, aluminum, etc.

Claims

[1] Battery cell (10), comprising: a housing (50) having a bottom surface (90); a stack (12) of anode electrodes (40-1, 40-2, 40-A) and cathode electrodes (20-1, 20-2, 20-C) within the housing (50); a vent opening (80) formed in the bottom surface (90) of the housing (50) and configured to open to allow gas to escape from the interior of the housing (50) when the pressure within the housing (50) exceeds a threshold value; and a support (110D) within the housing (50) resting on the bottom surface (90) and supporting the stack (12), the support (110D) defining at least one passage through the support (110D) configured to allow gas to flow through the support (110D) to the vent opening; characterized by , that the holder (110D) comprises a support (130D) which is penetrated by a single opening (140D) and which is folded in an accordion-like manner such that the folds of the fold extend beyond the one opening (140D). [2] Battery cell (10) according to claim 1, wherein the battery cell (10) is designed as a prismatic cell.

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