EP-4736262-A1 - HIGH-VOLTAGE BATTERY

EP4736262A1EP 4736262 A1EP4736262 A1EP 4736262A1EP-4736262-A1

Abstract

The invention relates to a high-voltage battery (1) acting as a traction battery for a motor vehicle, the high-voltage battery comprising a plurality of individual battery cells (2), the battery terminals (8, 10) of which are arranged on a first side of a cell housing (4) and are connected by cell connectors (16), wherein each of the individual battery cells (2) has an overpressure relief element (12) which opens the cell housing (4) when a predefined pressure is exceeded therein, wherein the overpressure relief element (12) is arranged together with the battery terminals (8, 10) of the individual battery cell (2) on a first side of the cell housing (4), wherein the battery terminals (8, 10), which are connected by the cell connectors (16), and the overpressure relief element (12) are covered with an electrically insulating potting compound (20) that is chemically, mechanically, and thermally resistant. The high-voltage battery according to the invention is characterised in that the potting compound (20) comprises a phase change material (18).

Inventors

WIGGER, STEFAN
POTT, ANDRES
Pegel, Hendrik
UZUN, AHMET
Böld, Robin
GEISLER, TOBIAS

Assignees

Mercedes-Benz Group AG

Dates

Publication Date: 20260506
Application Date: 20241112

Claims (9)

1. A high-voltage battery (1) as a traction battery for a motor vehicle, comprising a plurality of individual battery cells (2), the battery terminals (8, 10) of which are arranged on a first side of a cell housing (4) and connected by cell connectors (16), each of the individual battery cells (2) having an overpressure relief element (12) which opens the cell housing (4) when a predetermined pressure is reached, the overpressure relief element (12) being arranged together with the battery terminals (8, 10) of the individual battery cell (2) on a first side of the cell housing (4), the battery terminals (8, 10) connected to the cell connectors (16) and the overpressure relief element (12) being covered by an electrically insulating, chemically, mechanically and temperature-resistant potting compound (20), characterized in that the potting compound (20) comprises a phase change material (18).
2. High-voltage battery (1) according to claim 1, characterized in that the phase change material (18) is designed as a microencapsulated phase change material (18).
3. High-voltage battery (1) according to claim 1 or 2, characterized in that the phase change material (18) has polymer-coated cores (21) with phase change properties.
4. High-voltage battery (1) according to claim 1, 2 or 3, characterized in that the phase change material (18) is designed in such a way that almost no volume change occurs during the phase change.
5. High-voltage battery (1) according to one of claims 1 to 4, characterized in that the phase change material (18) has a particle size of a few pm.
6. High-voltage battery (1) according to one of claims 1 to 5, characterized in that the potting compound (20) is based on polyurethane or on the basis of silicone.
7. High-voltage battery (1) according to one of claims 1 to 6, characterized by a heat exchanger (5) which, on a second side opposite the first side, is in heat-conducting contact with the cell housings (4) of the individual battery cells (2).
8. High-voltage battery (1) according to one of claims 1 to 7, characterized in that the individual battery cells (2) are designed as round cells.
9. High-voltage battery (1) according to one of claims 1 to 8, characterized in that the individual battery cells (2) are formed using lithium-ion technology with a liquid electrolyte.

Description

High-voltage battery The invention relates to a high-voltage battery as a traction battery for a motor vehicle, with a plurality of individual battery cells according to the type defined in more detail in the preamble of claim 1. So-called high-voltage batteries according to ECE R100 are known from the state of the art and are used, for example, in motor vehicles as traction batteries. They typically consist of one or more modules, each of which contains a plurality of individual battery cells, which can be implemented in various mechanical designs, for example, as round cells with a cup-shaped housing, as prismatic cells with a solid housing, or the like. Often, the battery terminals are located on one side of the housing of each individual battery cell, for example, to enable electrical contact of the fully assembled battery from above via cell connectors. Many currently common battery types, such as lithium-ion batteries, also feature an overpressure relief element that opens the cell housing in the event of thermal runaway of the individual battery cell, allowing the excess pressure to be released and hot gases to be released into the environment. This is typically referred to as cell venting. To prevent flames or sparks from escaping from the battery casing along with the hot gases, DE 102021 000 029 A1 describes a multi-layer protective element for thermal insulation that filters the escaping gases through a fiber layer. This prevents flames and sparks from escaping. From the applicant's two non-German prior publication applications 102023 128 877.6 and 102023 128 879.2, the use of electrically insulating casting compounds is also known to provide a protective cover for the cell connectors and the overpressure relief element. In addition, the individual battery cells require temperature control, typically cooling during operation, and possibly preheating during commissioning at very low ambient temperatures. Heat exchangers are provided for this purpose. These are generally arranged between the individual battery cells to ensure temperature control without locally competing with the battery terminals or the overpressure relief element. From DE 102021 005260 A1 it is further known to hold the cell connectors in an electrically insulating carrier, wherein this carrier, which holds and carries the cell connectors, has an embedded phase change material. Based on this initial situation, the object of the present invention is to provide an improved high-voltage battery which enables simple and efficient cooling. According to the invention, this object is achieved by a high-voltage battery having the features in claim 1, and in particular by the features in the characterizing part of claim 1. Advantageous embodiments and further developments of such a high-voltage battery according to the invention emerge from the dependent claims. In the high-voltage battery according to the invention, it is provided that the overpressure relief element is provided together with the battery terminals of the individual battery cell on a first side of the cell housing, wherein the battery terminals connected to the cell connectors and the overpressure relief element are covered with an electrically insulating, temperature-resistant potting compound. This can preferably be designed such that, in the event of the overpressure relief element being activated, it ruptures in the area of the affected individual battery cell, and only in this area. The high-voltage battery thus achieves a very A compact design in which both the cell venting via the overpressure relief element and the battery terminals, which are connected to the cell connectors, are arranged on the same side. A further side, in particular the opposite side, can then, according to a very advantageous development, be connected to a heat exchanger, for example, a cooled base plate. No installation space for cooling is then required between the individual battery cells. For the high-voltage battery according to the invention, it is crucial that the potting compound contains a phase-change material. The phase-change material in the area of the potting compound can be added very easily and efficiently as a filler to the potting compound. With minimal effort and without requiring additional installation space, this phase-change material can now cool the cell connectors, as well as the battery terminal connected to them and the top of the cell housing when needed. Such a need arises predominantly when the individual battery cells are being charged at high power or when very high power is required, for example during acceleration while driving uphill. In such operating phases in which a large amount of waste heat is generated, the phase-change material can absorb heat by changing from a solid to a liquid phase. During subsequent normal operation, this heat can then be released back into the individual battery cell and dissipated by conventional cooling, so that the cooling