The present invention relates to a battery unit that contains a stack of flat cells, between which metal sheets are placed. Each metal sheet has at least one angled edge.
A similar battery unit is, for example, described in DE 10 2008 016 936 A2. There, the edges of the metal cooling sheets are bent at 90 degrees in order to cover the cells in a form-fitting way and to thereby provide a connection to a heat sink.
Battery units of this type can create levels of pressure inside the cells through overheating, short circuits, or other electrical incidents that cause the cells to burst and subsequently leak the gas that was created in the cells. This process can even lead to the formation of flames. If the flames spread to an adjacent cell, that cell may also overheat, resulting in a chain reaction that can pose a serious safety risk.
The goal of this invention is to create a battery unit inside of which the respective cells are better protected against gas leaks and flames.
This goal is achieved through a battery unit of the aforementioned type, which however, according to the invention, is characterized by adjacent metal cooling sheets having their edges angled in the same direction. Furthermore, these edges partially overlap in order to form die gaps, which are aligned in the same direction.
Thanks to these design features, any gas escaping from a cell is deflected to the side and diverted away from any adjacent—and any opposite—cells, so that these cells are effectively protected from the gases or flames emanating from a single faulty cell. This setup reduces the risk of a chain reaction and, as a result, enables the production of low-cost battery units with considerably enhanced levels of operating safety.
The angle of the bend is preferably greater than or equal to 45 degrees and smaller than 90 degrees. Most preferably, the angle is between about 70 degrees and 85 degrees in order to form a die gap that points as far as possible sideways.
When the battery unit is situated next to at least two adjacent stacks of cells, then the edges inside the battery unit are aligned in the same direction, especially if viewed in three dimensions, in order to protect the respectively opposite stack. In a particular variation of the invention, when the battery unit has at least two adjacent stacks of cells, edges that are opposite to each other in the battery unit are angled in the same direction or in a mirror-symmetric way in order to protect the respectively opposite stack.
Furthermore, the edge design of the present invention creates the possibility to curl the metal cooling sheets in an area close to the edges, so that the cells are protected against slipping towards the edges, which constitutes an additional preferable feature of the invention.
The invention is described in more detail in the enclosed figures and drawings, which present an implementation example. The drawings demonstrate
According to
The angle α formed between the metal sheets and their bent edges 5 is preferably greater than or equal to 45 degrees, but in any case less than 90 degrees, in order to create the die gaps 6. Preferably, the angle α is between 70 degrees and 85 degrees, and ideally around 80 degrees.
In areas 8 that are directly adjacent to the edges 5, the cooling plates 4 are curled in order to prevent the directly adjacent cells (s) from sliding all the way to the edges (5).
The invention is not limited to the illustrated implementation example, but includes all variations and modifications that fall within the scope of the claims listed below.
Number | Date | Country | Kind |
---|---|---|---|
10 2009 020 787.2 | May 2009 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCT/EP2010/056506 | 5/11/2010 | WO | 00 | 11/10/2011 |