Traction battery of a motor vehicle and motor vehicle

Abstract

Traction battery (11) of a motor vehicle (10), comprising a plurality of battery cells (12), each of the battery cells (12) having a first electrode (13) serving as a cathode, a second electrode (14) serving as an anode, an electrolyte (15) arranged between the electrodes (13, 14), and a separator (16) arranged between the electrodes (13, 14), and wherein the separator (16) is a membrane made of poly-(meta phenylene isophthalamide) with a framework compound made of zeolitic imidazolate, the framework compound made of zeolitic imidazolate making up 80% by volume to 99% by volume of the separator (16) and the poly-(meta phenylene isophthalamide) making up 20% by volume to 1% by volume of the separator (16).

Description

[0001] The invention relates to a traction battery of a motor vehicle and a motor vehicle with at least one traction battery.

[0002] The structure of a motor vehicle's traction battery is well known. A traction battery comprises several battery cells. The battery cells are arranged either directly in a battery housing of the traction battery or indirectly in battery module housings of battery modules of the traction battery, which are positioned within the battery housing. The main components of a battery cell of a traction battery are an anode, a cathode, an electrolyte, and a separator. The electrolyte and separator are arranged between the anode and cathode.

[0003] US 2024 / 0 021 804 A1 shows the basic structure of a battery cell with an anode, a cathode, an electrolyte and a separator.

[0004] EP 2 677 591 B1 discloses a secondary battery.

[0005] CN 1 15 810 867 A1, CN 1 13 571 840 A1, CN 1 13 594 628 A, CN 1 17 342 567 A disclose separators of battery cells.

[0006] CN 1 17 613 509 A discloses a separator of a lithium-sulfur battery.

[0007] WO 2021 / 200 587 A1 discloses further prior art.

[0008] In a motor vehicle's traction battery, thermal runaway, which can lead to the battery burning out, must be avoided. Therefore, there is a need for a traction battery with a reduced risk of thermal runaway. Currently known battery cell separators are only stable at temperatures up to 120°C. At temperatures above 120°C, there is a risk of the separators decomposing, causing a short circuit and, as a result, thermal runaway of the battery cell and thus the traction battery.

[0009] There is a need for a traction battery with a reduced risk of thermal runaway.

[0010] The object of the invention is to create a novel traction battery of a motor vehicle and a motor vehicle with at least one such traction battery.

[0011] This object is achieved by a traction battery according to patent claim 1 and a motor vehicle according to patent claim 7.

[0012] According to the invention, the separator of the battery cells of the traction battery is a membrane made of poly-(meta-phenylene isophthalamide) with a framework compound made of zeolitic imidazolate, wherein the framework compound made of zeolitic imidazolate makes up 80 vol.% to 99 vol.% of the separator and the poly(meta-phenylene isophthalamide) makes up 20 vol.% to 1 vol.% of the separator.

[0013] The separator of the battery cells of the traction battery according to the invention is stable even at temperatures of up to 250°C or even up to 300°C. In particular, in the temperature range from 120°C to 300°C, there is no risk of the separator of the battery cells of the traction battery according to the invention decomposing. The traction battery according to the invention has a reduced risk of thermal runaway.

[0014] Preferably, the zeolitic imidazolate framework compound is a metal-organic framework compound containing cobalt. This can further improve the thermal stability of the separator and reduce the risk of thermal runaway of the traction battery.

[0015] Preferred developments of the invention emerge from the subclaims and the following description.

[0016] Exemplary embodiments of the invention are explained in more detail with reference to the drawings, without being limited thereto. Fig. 1 is a schematic view of a motor vehicle with a traction battery, Fig. 2 a schematic view of a battery cell of the traction battery of the motor vehicle.

[0017] Fig. 1 shows a motor vehicle 100 with a traction battery 11. The traction battery 11 is a rechargeable battery having several battery cells 12, wherein Fig. 2 shows a highly schematic view of the structure of a battery cell 12.

[0018] The battery cells 12 are arranged either directly in a battery housing of the traction battery or indirectly in battery module housings of battery modules of the traction battery, which are positioned in the battery housing.

[0019] The main components of a battery cell 12 are a first electrode 13 serving as a cathode, a second electrode 14 serving as an anode, an electrolyte 15 arranged between the electrodes 13, 14 and a separator 16 also arranged between the electrodes 13, 14. Furthermore, Fig. 1 a battery cell housing 17.

[0020] The separator 16 of the battery cell 12 is a membrane made of poly(meta-phenylene isophthalamide) with a framework compound made of zeolitic imidazolate.

[0021] Poly(meta-phenylene isophthalamide) can be abbreviated as PMIA and zeolitic imidazolate as ZIF-L.

[0022] The zeolitic imidazolate framework compound is formed in situ in the poly(meta-phenylene-isophthalamide) membrane and provides a metal-organic framework compound preferably containing cobalt (Co). Zeolitic imidazolate with cobalt can be abbreviated as ZIF-L(Co).

[0023] The separator, consisting of the poly(meta-phenylene isophthalamide) membrane and the zeolitic imidazolate framework compound, which preferably contains cobalt, exhibits thermal stability of up to 250°C or even up to 300°C and a tensile strength of more than 10 MPa. Such a separator 16 is highly temperature-stable, meaning it does not decompose at temperatures of up to 250°C or even up to 300°C, thus preventing the risk of thermal runaway of the battery cell due to a short circuit between the anode and cathode.

[0024] In a lithium battery or a lithium-sulfur battery, the separator 16 effectively suppresses lithium dendrite growth, especially from a lithium anode. High charging and discharging performance can be achieved.

[0025] The framework compound of zeolitic imidazolate, which preferably contains cobalt, makes up 80 vol.% to 99 vol.%, preferably 80 vol.% to 97 vol.%, particularly preferably 85 vol.% to 95 vol.% of the separator.

[0026] The poly-(meta phenylene isophthalamide) makes up 20 vol.% to 1 vol.%, preferably 20 vol.% to 3 vol.%, particularly preferably 15 vol.% to 5 vol.%, of the separator 16.

[0027] The invention accordingly provides a traction battery 11 of a motor vehicle 100 with battery cells 12 which have a thermotolerant separator 16.

[0028] The battery cells 12 are preferably lithium-ion battery cells or lithium-sulfur battery cells. In the case of lithium-sulfur battery cells, the separator 16 allows for a high sulfur loading and a low electrolyte-to-sulfur ratio.

Claims

[1] Traction battery (11) of a motor vehicle (10), with several battery cells (12), wherein each of the battery cells (12) has a first electrode (13) serving as a cathode, a second electrode (14) serving as an anode, an electrolyte (15) arranged between the electrodes (13, 14) and a separator (16) arranged between the electrodes (13, 14), characterized by , that the separator (16) is a membrane made of poly(meta-phenylene isophthalamide) with a framework compound made of zeolitic imidazolate, wherein the framework compound made of zeolitic imidazolate makes up 80 vol.% to 99 vol.% of the separator (16) and the poly(meta-phenylene isophthalamide) makes up 20 vol.% to 1 vol.% of the separator (16). [2] Traction battery (11) according to claim 1, characterized by that the framework compound made of zeolitic imidazolate is a metal-organic framework compound. [3] Traction battery (11) according to claim 1 or 2, characterized by that the framework compound of zeolitic imidazolate contains cobalt. [4] Traction battery (11) according to claim 1, 2 or 3, characterized by that the framework compound of zeolitic imidazolate constitutes 80 vol.% to 97 vol.% of the separator (16) and the poly(meta-phenylene isophthalamide) constitutes 20 vol.% to 3 vol.% of the separator (16). [5] Traction battery (11) according to claim 1, 2 or 3, characterized by that the framework compound of zeolitic imidazolate constitutes 85 vol.% to 95 vol.% of the separator (16) and the poly(meta-phenylene isophthalamide) constitutes 15 vol.% to 5 vol.% of the separator (16). [6] Traction battery (11) according to one of claims 1 to 5, characterized by that it is a lithium battery or a lithium-sulfur battery with lithium battery cells or lithium-sulfur battery cells. [7] Motor vehicle (10) with at least one traction battery (11) according to one of claims 1 to 6.

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