DE-102014213719-B4 - Battery of an electric motor vehicle

Abstract

Accumulator (10) of an electric drive of a motor vehicle, comprising at least one cell (12) and an insulating film (18) which protects the accumulator (10) from deformation by external force and/or counteracts gas leakage, characterized in that the cell (12) is surrounded on the outside by the insulating film (18), and/or the insulating film (18) surrounds a cell stack (20) of the accumulator (10), and/or electrically conductive cell connectors (22) are surrounded by the insulating film (18), and/or anode terminals (14) and cathode terminals (16) of the cell(s) (12) are surrounded by the insulating film (18), and/or the insulating foil (18) is arranged on the outside of a module frame of the accumulator (10).

Inventors

• Björn Lath
• Daniel Loos
• Robert Lustig
• Andreas Schleicher

Assignees

• BAYERISCHE MOTOREN WERKE AKTIENGESELLSCHAFT

Dates

Publication Date

20260513

Application Date

20140715

Claims (5)

1. Accumulator (10) of an electric drive of a motor vehicle, comprising at least one cell (12) and an insulating film (18) which protects the accumulator (10) from deformation by external force and/or counteracts gas leakage, characterized in that the cell (12) is surrounded on the outside by the insulating film (18), and/or the insulating film (18) surrounds a cell stack (20) of the accumulator (10), and/or electrically conductive cell connectors (22) are surrounded by the insulating film (18), and/or anode terminals (14) and cathode terminals (16) of the cell(s) (12) are surrounded by the insulating film (18), and/or the insulating film (18) is arranged on the outside of a module frame of the accumulator (10).
2. Accumulator (10) after Claim 1 , characterized in that the insulating film (18) is a polyimide film.
3. Accumulator (10) after Claim 1 or 2 , characterized in that the insulating film (18) is arranged inside the cell (12).
4. Accumulator (10) according to one of the preceding claims, characterized in that the insulating film (18) is arranged in several superimposed layers.
5. Accumulator (10) according to one of the preceding claims, characterized in that the insulating film (18) is glued.

Description

The invention relates to an accumulator for an electric drive of a motor vehicle. The use of batteries in electric vehicles necessitates a high installed energy capacity due to the general desire for long ranges. To guarantee passenger safety at all times, the highest possible resistance to deformation of the battery caused by external forces must be ensured, as otherwise the battery's secondary cells could ignite and decompose. Furthermore, legal guidelines exist for the introduction of electrified vehicles into certain markets, prescribing a minimum level of required deformation and force input before the battery ignites. This set of requirements also takes into account the number of secondary cells to be considered, as an electrical energy storage system typically consists of several batteries or battery cells interconnected. A secondary cell of a battery (hereinafter referred to simply as a cell) ignites when the ignition temperature of the electrolyte within the cell is reached or when the electrolyte comes into contact with a spark. In the case of battery deformation, this is due to a short circuit, as this generates significant heat. In batteries with only a single cell, such a short circuit can logically only occur within that single cell. In contrast, in the case of a cell stack, a short circuit can also result from the interaction of two adjacent cells. For cell modules, an interaction between a module frame of the battery and a cell can also cause a short circuit. Finally, it should also be noted that the ignition of a single cell can trigger a chain reaction, causing other cells to ignite and decompose. Out of JP 2000-173564 A , US 2012/0276441 A1 and JP 2002/175790 A These are accumulators or batteries designed for mobile devices such as laptops or power tools, characterized by special protective measures against shocks, vibrations, drops, etc. However, these accumulators are not suitable for the electric propulsion of a motor vehicle. DE 10 2011 003 741 A1 This describes a battery cell for powering a motor vehicle, comprising a housing and a plurality of electrodes arranged in a winding within the housing. A layer of dielectric strength material is positioned between an uncoated metallic area of the winding and the housing, covering at least part of the uncoated metallic area. Additionally, the inside of the housing may be coated, at least partially, with an insulating film to prevent a short circuit between an electrode and the housing. The object of the invention is to increase the safety of accumulators, in particular accumulators for the electric drive of a motor vehicle. This problem is solved by an accumulator with the features of claim 1. Advantageous and suitable embodiments of the accumulator according to the invention are specified in the dependent claims. The accumulator according to the invention is part of an electric drive system for a motor vehicle and comprises at least one cell. According to the invention, an insulating film is provided which protects the accumulator, i.e., the entire accumulator or at least a part thereof, from deformation caused by external forces and/or prevents gas leakage. The invention is based on the finding that the use of an insulating film can reduce the deformability of a battery or its sensitivity to applied force to such an extent that the risk of ignition due to a short circuit is significantly reduced. The insulating film therefore contributes to improving the safety of batteries in the event of unwanted or unintentional mechanical manipulation. The use of the insulating film according to the invention largely prevents the interaction of a cell or part of a cell with neighboring components, which could lead to a short circuit, depending on the location of application. Furthermore, the insulating film ensures that in the event of a short circuit inside a cell, neighboring cells are less affected by the cell's decomposition, or ideally, not affected at all. If the decomposition process of a cell has begun and gas is emitted, the film's durability prevents the gas from escaping, or at most, from escaping only through a small opening, such as a narrow gap. This prevents gas from escaping. throttled so that in case of ignition, the flame will go out again. To best fulfill these tasks, the insulating film should exhibit excellent chemical and thermal resistance as well as mechanical strength. A polyimide film, particularly Kapton® film (a DuPont product), is suitable as an insulating film. Alternatively, other insulating films with similar properties can be used. According to a first aspect of the invention, the accumulator cell is surrounded on the outside by the insulating film. The insulating film can also be located inside the cell of the accumulator. According to a second aspect of the invention, the insulating film surrounds a cell stack when the accumulator comprises a plurality of interconnected cells. According to a third aspect of the invent