METAL-ION ACCUMULATOR PROVIDED WITH A DEGASSING DUCT, ASSOCIATED BATTERY MODULE OR BATTERY PACK WITH LIQUID COOLING

Abstract

The invention relates to a metal-ion electrochemical battery or accumulator, comprising: a housing (6) of longitudinal axis (X), a rupture zone (60) of a part of the housing, forming a safety vent for the degassing of the accumulator, at least one duct (10) comprising at least one rigid part (14) forming a stiffener, fixed or formed integrally with the part of the housing, around the safety vent, and a flexible part (15) arranged tightly with the housing or with the stiffener which is itself tight with respect to the housing, in the extension of the stiffener and around the latter, the flexible part being adapted to be deformed elastically on three orthogonal axes (X, Y, Z), so as to compensate for the plays on these axes when it is inserted and held tightly in a through opening (12) of a casing (11) of a module or battery pack.

Claims

1. A metal-ion electrochemical battery or accumulator, comprising: a housing of longitudinal axis, a rupture zone of a part of the housing, forming a safety vent for the degassing of the accumulator, at least one duct comprising at least one rigid part forming a stiffener, fixed or formed integrally with the part of the housing, around the safety vent, and a flexible part arranged tightly with the housing or with the stiffener that is itself tight with respect to the housing, in the extension of the stiffener and around the latter, the flexible part being adapted to be deformed elastically on three orthogonal axes, so as to compensate for the plays on these axes when it is inserted and held tightly in a through opening of a casing of a module or battery pack.

2. The metal-ion electrochemical battery or accumulator according to claim 1, wherein the stiffener and the flexible part constitutes a single one-piece part.

3. The metal-ion electrochemical battery or accumulator according to claim 2, wherein the stiffener is a part directly fixed onto the part of the housing, the flexible part being overmolded on the stiffener.

4. The metal-ion electrochemical battery or accumulator according to claim 2, wherein the flexible part is a part directly fixed onto the part of the housing, the stiffener comprising at least one ring overmolded inside the flexible part.

5. The metal-ion electrochemical battery or accumulator according to claim 1, wherein the stiffener is a part distinct from a part forming the flexible part.

6. The metal-ion electrochemical battery or accumulator according to claim 5, wherein the part forming the stiffener is directly fixed onto the part of the housing, the part forming the flexible part being also directly fixed onto the part of the housing.

7. The metal-ion electrochemical battery or accumulator according to claim 5, wherein the stiffener is a part directly fixed onto the part of the housing, the flexible part being an elastic ring force-fitted onto the stiffener.

8. The metal-ion electrochemical battery or accumulator according to claim 5, wherein the top portion of the stiffener comprise at least two lugs that are diametrically opposite in a radial direction of the duct and that protrude outward therefrom.

9. The metal-ion electrochemical battery or accumulator according to claim 1, wherein the flexible part is a bellows comprising: a fixing portion forming a base, a central portion in the extension of the base, comprising at least one fold adapted to be deformed elastically on the three orthogonal axes, a blocking portion in the extension of the central portion, the blocking portion being adapted to be inserted and held in the through opening.

10. The metal-ion electrochemical battery or accumulator according to claim 1, wherein the stiffener is made of a high-temperature plastic, chosen from among polyetheretherketone (PEEK) or polyetherimide (PEI), or made of aluminum, or of ceramic.

11. The metal-ion electrochemical battery or accumulator according to claim 1, wherein the flexible part is made of elastomer chosen from among a rubber, a nitrile or a silicone.

12. The metal-ion electrochemical battery or accumulator according to claim 1, wherein the flexible part comprises, at its free end, a precut tapered end-fitting, adapted to produce the centering and the positioning of the flexible part in the through opening.

13. A module or battery pack, comprising: a plurality of metal-ion electrochemical batteries or accumulators according to claim 1, a heat-transfer fluid circuit for cooling or heating up the accumulators, comprising a tank of heat-transfer fluid in which the accumulators are immersed, the tank comprising a casing drilled with a plurality of through openings in each of which the flexible part of an accumulator duct is inserted and held tightly.

14. The module or battery pack according to claim 13, comprising, as member for tightly holding the flexible part of the duct of each accumulator, a fixing flange force-fitted in the flexible part inserted into a through opening.

15. The module or battery pack according to claim 13, configured so that each accumulator duct can discharge the gases likely to be given off through its vent, in a space outside of the casing of the module or battery pack.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0105] FIG. 1 is an exploded perspective schematic view showing the various elements of a lithium-ion accumulator.

[0106] FIG. 2 is a front view showing a lithium-ion accumulator with its flexible packaging according to the state of the art.

[0107] FIG. 3 is a perspective view of a lithium-ion accumulator according to the state of the art with its rigid packaging consisting of a housing of cylindrical form.

[0108] FIG. 4 is a perspective view of a lithium-ion accumulator according to the state of the art with its rigid packaging consisting of a housing of prismatic form.

[0109] FIG. 5 is a perspective view of an assembly, by means of busbars, of lithium-ion accumulators of cylindrical geometry according to the state of the art, forming a battery pack.

[0110] FIG. 6 is a perspective view of an example of mounting of a lithium-ion accumulator of prismatic geometry according to the invention in a battery pack casing.

[0111] FIG. 7 is a partial longitudinal cross-sectional view of FIG. 6, showing in detail the accumulator provided with its duct according to the invention.

[0112] FIG. 8 is a top view of a lithium-ion accumulator of prismatic geometry according to the invention, showing the safety vent.

[0113] FIG. 9 is a perspective view of a first embodiment of a duct as fixed to an accumulator according to the invention.

[0114] FIG. 10 is a perspective view of the flexible part of the duct according to FIG. 9.

[0115] FIG. 11 is a perspective view of the rigid part of the duct according to FIG. 9.

[0116] FIG. 12 is a perspective view of a second embodiment of a duct according to the invention.

[0117] FIG. 13 is a perspective view of a third embodiment of a duct according to the invention.

[0118] FIG. 14 is a perspective view of a fourth embodiment of a duct according to the invention.

[0119] FIG. 15 refers back to FIG. 9, showing by transparency the rigid part surrounded by the flexible part of the duct according to the invention.

[0120] FIG. 16 is a perspective view of a variant of the duct according to FIG. 15.

[0121] FIG. 17 is a perspective view of a variant of the flexible part of a duct according to the invention, according to which a precut tapered end-fitting is arranged.

[0122] FIG. 18 is a perspective view of a battery pack with the placement in the casing for each of the accumulators by means of a tapered end-fitting according to FIG. 17.

DETAILED DESCRIPTION

[0123] FIGS. 1 to 5 relate to different examples of a Li-ion accumulator, with flexible packagings and accumulator housings and a battery pack according to the state of the art. These FIGS. 1 to 5 have already been commented on in the preamble and are not therefore discussed more hereinbelow.

[0124] For clarity, the same references designating the same elements according to the state of the art and according to the invention are used for all the FIGS. 1 to 18.

[0125] Throughout the present application, the terms “low”, “high”, “below”, “above”, “bottom” and “top” should be understood with reference to the arrangement of a metal-ion accumulator according to the invention vertically in a battery pack.

[0126] FIGS. 6 and 7 illustrate a Li-ion accumulator of prismatic geometry of longitudinal axis X with a duct 10 according to the invention, and as it is inserted into a battery pack casing 11.

[0127] The casing 11 is that of a tank of heat-transfer liquid in which the Li-ion accumulators according to the invention are at least partially immersed.

[0128] As illustrated, the duct 10 is inserted into a through opening 12 and is held with the accumulator in the latter by means of a fixing flange 13 according to a plugging method.

[0129] More specifically, the duct 10 comprises a rigid part forming a stiffener 14, fixed tightly to the cover 9 of the accumulator housing 6, around the safety vent 60. The section of the stiffener 14 corresponds to that of the vent 60, which makes it possible to comply with and secure the section of passage of the gas flows defined by the manufacturer of the accumulator.

[0130] The stiffener 14 can be made of high-temperature technical plastic of PEEK or PEI type. It can be bonded directly to the cover 9 of the housing around the safety vent 60.

[0131] The duct 10 also comprises a flexible part 15 arranged tightly in the extension of the stiffener 14 and around the latter.

[0132] As illustrated in FIGS. 6 and 7, one end of the flexible part 15 is fixed directly onto the cover 9 of the housing 6 and/or onto the stiffener 14, while the other end is inserted into the through opening 12 and held therein by the fixing flange 13 which is force-fitted therein.

[0133] The integrity of the flexible part 15 subjected to the mechanical stresses of pressure or crushing types, notably by the heat-transfer liquid in the tank, is ensured by the stiffener 14.

[0134] The flexible part 15 can be made of elastomer, such as a rubber, a nitrile, a silicone.

[0135] According to the invention, the flexible part 15 adapted to be deformed elastically on three orthogonal axes (X, Y, Z), so as to compensate for the plays on these axes. The plays can be those linked to the assembly of each accumulator in the casing of a module or battery pack, or minor movements of the accumulators linked to their geometrical variations during their lifetime, such as volume variations in cycling.

[0136] As an example, the flexible part 15 can be dimensioned with a possible deformation of +/−1.5 mm on the axes X-Y and 0 to 2 mm on the axis Z.

[0137] The duct 10 as such and its two parts 14, 15 of which it is formed are represented in FIGS. 9 to 11.

[0138] The stiffener 14 comprises, in its top part, two lugs 140 that are diametrically opposite in a radial direction of the duct and that protrude outward therefrom. The function of these lugs 140 is to limit the deformation (crushing) of the flexible part 15 under the various possible stresses linked to the environment, more particularly to the liquid cooling of the battery pack, inside the casing.

[0139] The part 15 forming the flexible part is a bellows comprising three adjacent portions 150, 151, 152.

[0140] The annular portion 150 forming the base of the bellows serves as plane of bonding to the cover 9 of the housing 6 or to the stiffener 14. The bonding is done by deposition of a bead of glue on the cover 9 and the annular portion 150 is pressed against this bead of glue.

[0141] The central portion 151 in the extension of the base 150 comprises a gauged fold whose function is to compensate for the plays on the 3 axes X, Y, Z.

[0142] The top portion 152 in the extension of the central portion 151 allows the insertion and the blocking of the bellows 14 in a through opening 12 of the casing 11.

[0143] Various other embodiments of the degassing duct 10 based on overmolding can be envisaged in order to simplify the mounting and the incorporation of the duct and also lower the production costs for significant volumes.

[0144] FIG. 12 shows a flexible part 15′ directly overmolded on the stiffener 14. In this FIG. 12, the visible holes, produced on the top periphery of the stiffener 14, serve as a die for the attachment of the flexible material of the overmolded part 15′.

[0145] FIG. 13 illustrates an overmolding of two rigid rings 14.1, 14.2 forming the stiffener 14 directly inside the bellows 15.

[0146] FIG. 14 illustrates an embodiment whereby the stiffener 14 extends over the entire height, i.e. from the cover 9 of the housing 6 to the top part of the through opening, an elastic ring 15″ of silentbloc type forming the flexible part being force-fitted around the top part of the stiffener 14.

[0147] In the embodiment in which the bellows 15 completely surrounds the stiffener 14, two rectilinear lugs 140 can be provided in the form of small bars, that are diametrically opposite (FIG. 15), or a greater number of spot lugs 140 (FIG. 16).

[0148] As shown in FIGS. 17 and 18, in order to facilitate the placement of the bellows 15 upon the closure of the casing 11 of the battery pack, it is possible to implement a precut tapered end-fitting 16 at the top end of the bellows 15. This tapered end-fitting 6 allows the centering and the positioning of the bellows 15 through a through opening 12 of the casing 11.

[0149] Once the positioning has been done, the tapered end-fitting 16 is cut easily, in order to allow the duct 10 to emerge on the outside of the casing 11 and allow the final fixing, notably by means of a fixing flange 13 in a plugging method.

[0150] At the end of this method, with the duct 10 emerging on the outside, the safety vent is in contact with the outside atmosphere.

[0151] The invention is not limited to the examples which have just been described; notably, features of the examples illustrated can be combined with one another in variants that are not illustrated.

[0152] Other variants and enhancements can be envisaged without in any way departing from the scope of the invention.

[0153] While, in the example illustrated, the safety vent has an elliptical section, it is possible to envisage any other vent section and consequently duct section, notably a cylindrical section.

[0154] Also, while the duct according to the invention around the safety vent can consist, as previously described, of two different parts, it can perfectly well be produced as a single part, preferably made of a single material, fixed directly and tightly to the housing. In the case of a single part, the choice of the material and its dimensioning should be made to guarantee both the integrity of the duct as such with respect to the degassing and the coolant and sufficiently flexible to compensate for the plays. Typically, the material can be a grade of rubber with a local thickening to locally provide greater rigidity.