Device for discharging hot gas of a battery cell

Abstract

The invention relates to a device for discharging hot gas of a battery cell (1) in a degassing state, wherein at least one degassing channel (2) comprising an inlet (3) is connected to a degassing opening (4) of the battery cell (1). In order to design such a device in such a way that hot gas exiting the battery cell can be reliably discharged even in the case of degassing channels with compact dimensions, in particular degassing channels with a smaller channel cross-section, the invention proposes that the inlet (3) is provided with a lubricant body which is provided with a lubricant for preventing cell particles from adhering.

Description

[0001] Device for discharging hot gas from a battery cell

[0002] Technical area

[0003] The invention relates to a device for discharging hot gas from a battery cell in an outgassing state, wherein at least one outgassing channel with an inlet is connected to an outgassing opening of the battery cell.

[0004] State of the art

[0005] In battery cells, such as those used in battery modules for high-voltage applications, a cell defect can lead to outgassing. To prevent subsequent thermal runaway, the hot gas escaping from the battery cell is generally discharged via an outgassing duct, which has an inlet connected to an outgassing opening in the battery cell. To achieve the most compact module design possible, it is advisable to dimension such outgassing ducts accordingly, i.e., in particular, with a small duct cross-section.

[0006] However, practice has shown that the cell particles contained in the hot gas adhere particularly to the inlet of the outgassing channel, so that the resulting particle agglomeration can lead to blockage of the outgassing channel. Consequently, the removal of the hot gas becomes difficult or, in the worst case, impossible.

[0007] Description of the invention The invention is therefore based on the object of designing a device of the type described at the outset in such a way that escaping hot gas can be reliably discharged even with compactly dimensioned outgassing channels, in particular with a smaller channel cross section.

[0008] The invention solves the stated problem by providing a lubricant body in the inlet which is provided with a lubricant to prevent the adhesion of cell particles.

[0009] As a result of these features, lubricant is supplied to the outgassing channel in the inlet through the lubricant body, so that the adhesive interaction between cell particles and channel wall is essentially prevented or the friction coefficient between cell particles and channel wall is reduced to such an extent that adhesion of the cell particles and thus particle agglomeration leading to blockage of the outgassing channel is avoided. In principle, it is irrelevant for the effect according to the invention whether the lubricant is only released when the battery cell is in the outgassing state or whether the lubricant from the lubricant body is already supplied to the inlet of the outgassing channel in the normal state of the battery cell and acts, for example, as lubrication for the channel wall. In the outgassing channel, the lubricant body is preferably arranged such that it is located in the hot gas stream that forms when the battery cell is in the outgassing state.It is particularly advantageous, for example, if the lubricant body is located opposite the outgassing opening of the battery cell with respect to an outgassing direction. With regard to simple design and manufacturing conditions, it is also recommended that the lubricant body be made of a polymeric material that, in the event of outgassing, is exposed to the hot gas from the defective battery cell and consequently melts or burns off, as well as releasing fillers that act as lubricants. A lubricant body that is meltable due to hot gas can, for example, be made of a thermoplastic matrix, preferably polyamide-based, and / or a thermoplastic-elastomer matrix. The corresponding plastic matrices can generally be filler-free, so that the lubricating effect results solely from the polymeric sliding properties of the plastic matrix in the molten state.For improved lubricating properties, the thermoplastic or thermoplastic-elastomer matrix can also be provided with fillers that act as lubricants. In the case of a thermosetting matrix, however, it is expedient if fillers that act as lubricants are embedded in it in such a way that they are released when the matrix burns. The features according to the invention thus create the prerequisite for the outgassing channel connected to the outgassing opening of the battery cell to be dimensioned more compactly. For example, the volume of this outgassing channel can be less than 30% of the volume of the battery cell.

[0010] If the lubricant body forms a preferably polymeric coating of the outgassing channel, a layer thickness in the range of 0.5 to 10 mm is recommended. The layer thickness depends on the enthalpy of fusion, the abrasion resistance of the coating material, the flow behavior in the outgassing channel, the hot gas temperature, the heat transfer between the gas and the lubricant body layer, and the degassing time of the battery cell in the outgassing state.

[0011] In order to further improve the safety conditions in the event of an outgassing battery cell in addition to the effect according to the invention, it can also be provided that the lubricant body forms a protective element that at least partially covers the outgassing opening opposite the outgassing channel. In the event of outgassing, not only does the protective element melt or decompose due to hot gas, but the flow resistance resulting from the protective element also reduces any pressure peaks of the hot gas to such an extent that the risk of pressure-induced bursting of the surrounding components or of the outgassing channel itself is reduced. In the case of a battery cell opposite the outgassing battery cell in the outgassing direction, the protective element thus also protects the opposite battery cell from the escaping hot gas. It is recommended that the average protective element thickness be in the range of 0.5 to 10 mm.The average protective element thickness is understood to be the thickness or height of the protective element along a height direction emanating from the protective element base, which is averaged over the protective element width extending transversely to this height direction.

[0012] In this context, particularly advantageous design conditions arise when the protective element is arranged on a carrier plate having an opening for the battery cell and being connected to the battery cell along its longitudinal axis in a shear- and tensile-resistant manner. Thus, relative movement between the battery cell, the carrier plate, and a corresponding electrical conductor connected to the battery cell can be prevented, taking into account a tolerance range, since the carrier plate is connected to the battery cell along its longitudinal axis in a shear- and tensile-resistant manner, and the electrical conductor itself is preferably fixedly connected to the carrier plate, in particular, fixed to the carrier plate.In this way, the carrier plate, together with the electrical conductor, can follow any movements of the battery cell along the longitudinal axis through bending and / or twisting, whereby the protective elements and preferably also the electrical conductor are mechanically relieved and thus protected against forces acting in the tensile and shear directions. The carrier plate is preferably designed such that it forms a channel wall of a channel section of the outgassing channel, in particular in its inlet. To further simplify the mounting or assembly process, the protective element can have at least one locking lug on its side facing the carrier plate, which engages in a locking receptacle of the carrier plate.

[0013] Alternatively, an insulating plate can be provided which has predetermined breaking points around the circumference of the protective element forming the lubricant body. As a result of these features, the predetermined breaking points break when a battery cell is outgassing, with the gas-induced pressure energy dissipating, whereby the protective element melts and the lubricating effect can occur. In addition, any adjacent battery cells remain largely protected from the escaping hot gas by the insulating plate. In order to achieve this effect in a simple manner, the insulating plate can have perforations which define the circumference of the protective element and form the corresponding predetermined breaking points. The insulating plate can be provided separately or arranged on a corresponding carrier plate for the battery cell. For the purposes of the invention, the insulating plate does not necessarily have to be rigid orbe self-supporting, so that in the simplest case an insulating plate can also be understood as an insulating foil.

[0014] To better protect any surrounding battery cells from escaping hot gas when a battery cell is outgassing, the protective element can have a gas baffle that runs at least partially around its circumference and projects towards the outgassing opening when installed. This can provide a directed flow path for the escaping hot gas away from the surrounding battery cells. The gas baffle can be interrupted in sections such that an electrical conductor for the battery cells or its conductor end sections are guided through the interruptions. For even better protection, the opening on the side of the carrier plate opposite the battery cell can also be surrounded at least in sections by a gas baffle that preferably projects beyond the opening.

[0015] Particularly in the case of multiple battery cells, melting, decomposition, or detachment of the protective element due to outgassing from a defective battery cell not only poses the risk of hot gas exposure to surrounding battery cells, but also generally results in a loss of mechanical integrity of the structure housing the battery cells. To achieve the most robust design possible and to improve the protection of surrounding battery cells from escaping hot gas, the protective element can have a regular hexagonal base. Consequently, gaps between adjacent protective elements can be avoided in hexagonally densely packed battery cells, which not only provides favorable insulating properties but also creates the prerequisites for a structurally intact structure.

[0016] Brief description of the invention

[0017] The drawing shows an example of the subject matter of the invention.

[0018] Fig. 1 is a schematic exploded view of a device according to the invention with several battery cells and an exemplary lubricant body designed as a protective element,

[0019] Fig. 2 a section along the line II - II on a larger scale and

[0020] Fig. 3 is an oblique view showing the underside of a protective element, also on a larger scale.

[0021] Ways to implement the invention

[0022] A device for discharging hot gas from a battery cell 1 in an outgassing state comprises an outgassing channel 2, indicated by a dot-dash line, with an inlet 3 connected to an outgassing opening 4 of the battery cell 1. Fig. 1 schematically shows a composite of several battery cells 1, the composite comprising a carrier plate 5, a circuit board 6, and an insulating plate 7.

[0023] Provided in the inlet 3 is a lubricant body designed as a protective element 8, which is opposite the outgassing opening 4 of the battery cell 1 with respect to an outgassing direction A, as shown particularly in the sectional view according to Fig. 2. To prevent the outgassing channel 2 from becoming blocked by the released cell particles when a defective battery cell 1 is outgassing, the protective element 8 melts as a result of exposure to hot gas and acts as a lubricant. This prevents cell particles from adhering to the channel wall. The protective element is made of polyamide, for example.

[0024] The protective element 8 is arranged on the carrier plate 5, which has an opening 9 for the battery cells 1 and is connected to the respective battery cells 1 along its longitudinal axis 10 in a shear and tensile manner.

[0025] On the side of the carrier plate 5 opposite the battery cell 1, openings 9 are at least partially surrounded by a gas guide wall 11 that projects beyond the opening 9. The carrier plate 5 thus forms a channel wall of a channel section of the outgassing channel 2 in its inlet 3. As shown in Fig. 3, the protective element 8 can comprise a base area forming a regular hexagon. On its underside facing the carrier plate 5, the protective element 8 has a partially circumferential gas guide wall 12. For simple assembly conditions, the protective element 8 also comprises locking lugs 13 on its underside facing the carrier plate 5, which engage in locking receptacles 14 in the carrier plate 5. The locking receptacles 14 of the carrier plate 5 can be formed by the gas guide wall 11 of the carrier plate 5.

Claims

Patent claims 1. Device for discharging hot gas from a battery cell (1) in an outgassing state, wherein at least one outgassing channel (2) is connected by an inlet (3) to an outgassing opening (4) of the battery cell (1), characterized in that a lubricant body provided with a lubricant to prevent the adhesion of cell particles is provided in the inlet (3).

2. Device according to claim 1, characterized in that the lubricant body forms a coating of the outgassing channel (2).

3. Device according to claim 1, characterized in that the lubricant body forms a protective element (8) which at least partially covers the outgassing opening (4) with respect to the outgassing channel (2).

4. Device according to claim 3, characterized in that the protective element (8) is arranged on a carrier plate (5) having an opening (9) for the battery cell (1) and which is connected to the battery cell (1) along its longitudinal axis in a shear and tensile manner.

5. Device according to claim 4, characterized in that the protective element (8) has on its side facing the carrier plate (5) at least one locking lug (13) which engages in a locking receptacle (14) of the carrier plate (5).

6. Device according to claim 3, characterized by an insulating plate (7) which has predetermined breaking points circumferentially delimiting the protective element (8).

7. Device according to one of claims 3 to 6, characterized in that the protective element (8) has on its circumference a gas guide wall (12) which runs at least in sections and which, in the installed position, projects in the direction of the outgassing opening (4).

8. Device according to one of claims 3 to 7, characterized in that the protective element (8) has a base forming a regular hexagon.

9. Device according to one of claims 1 to 8, characterized in that the hot gas-meltable lubricant body is made of a thermoplastic and / or thermoplastic-elastomeric plastic matrix.

10. Device according to one of claims 1 to 8, characterized in that the lubricant body is made of a thermosetting plastic matrix, in which fillers are embedded in such a way that they burn off the plastic matrix and act as a lubricant.

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