High-voltage battery having at least two adjacent battery modules

Abstract

The invention relates to a high-voltage battery (1) having at least two adjacent battery modules (3) which are in electrical contact with one another, the battery modules (3) each having a module housing (4) which is connected to earth and is less high than individual battery cells (2) of the battery modules (3), and the electrical contact (6) between the battery modules (3) being located above the module housings (4). The high-voltage battery according to the invention is characterised in that a plastic element (10) is located between the upper edges of the adjacent module housings (4) and the electrical contact (6) between the battery modules (3).

Description

[0001] High-voltage battery with at least two adjacent battery modules

[0002] The invention relates to a high-voltage battery with at least two adjacent battery modules of the type defined in more detail in the preamble of claim 1.

[0003] High-voltage batteries, which are used, for example, in motor vehicles to store electrical drive energy, are known from the prior art. The term "high-voltage battery" is defined according to ECE R100, which classifies components with a minimum voltage of 60 V direct current as high-voltage components.

[0004] German patent DE 102022000465 describes such a battery, which is constructed as a stack of individual battery cells. These form a battery module, with several such battery modules being assembled within a battery housing to create the high-voltage battery.

[0005] WO 20247090936 Al describes a fire-resistant bus connection. This is provided with a silicone coating which ceramicizes at high temperatures.

[0006] From WO 2024 / 054098 Al, another fire-resistant bus connection made of a metal plate is known. There, insulation is used that forms a chemical bond with the metal plate to insulate the structure.

[0007] DE 102012 219782 A1 describes a battery module. This module is designed to be stackable with identical modules. DE 10 2020 200 006 A1 further discloses a vehicle battery in which an insulating layer is arranged between the battery modules and a housing cover of a battery housing. In addition, a separating element is provided which galvanically isolates the electrical series connection of the battery modules in the event of a thermal event.

[0008] High-voltage batteries, as used today for storing electrical energy in electric vehicles, are mostly based on lithium-ion technology. The individual battery cells have a correspondingly high energy density. If, for example, an internal short circuit occurs within one of these individual battery cells, a very large amount of heat can be generated. This causes a correspondingly large amount of gas to be released within the individual battery cell, which is typically vented into the environment via a pressure relief element or rupture element to relieve the stress on the structure. However, this process results in heat being transferred to neighboring cells, as described in the aforementioned prior art.

[0009] One potential problem is that hot gases and particles from the affected battery cell can cause short circuits within the battery module. This can occur, for example, if the hot gases and particles degrade insulating coatings, leading to a short circuit on electrically conductive elements that are relatively close together. For instance, a cell connector linking the positive terminals of two adjacent battery modules and the module housing, which is grounded, can cause a short circuit. Such a short circuit then further propagates the thermal event, which should ideally be contained as quickly as possible to ensure the safety of the assembly.

[0010] The object of the present invention is to provide an improved high-voltage battery with at least two adjacent battery modules, which is optimized with regard to a possible short circuit in the event of a thermal event.

[0011] According to the invention, this is achieved by a high-voltage battery with the features of claim 1, and in particular in the characterizing part of claim 1. Advantageous embodiments and further developments are described in the dependent claims. The high-voltage battery according to the invention comprises at least two adjacent battery modules which are electrically contacted with each other, i.e., in particular in the region of their current-carrying poles, have at least one cell connector spanning multiple modules as an electrical contact. The battery modules each have a module housing that is grounded, which is typically less tall than the individual battery cells themselves. The module housings are positioned relatively close to each other, so that only a small gap remains between them.

[0012] In the event of a thermal event, the cell connector—the electrical contact between the battery modules, which, according to a further advantageous development, is electrically insulated by a coating—can be damaged. For example, hot gases containing glowing and / or abrasive particles can damage the coating. This can then lead to a short circuit between the cell connector, which is connected to the positive terminal of one or both battery modules, and the module housings, which are grounded. In the event of a thermal event within one of the battery modules, this creates an additional critical area that can contribute to the thermal event spreading further and faster, in the worst case throughout the entire high-voltage battery.

[0013] To remedy this, the invention provides that a plastic element is arranged between the module housings and the electrical contact between the battery modules.

[0014] This plastic element can be designed to be made of a plastic that melts in the event of a thermal event within the battery modules. During production, the plastic element can be loosely inserted between the two adjacent module housings and the cell connectors. "Loosely" in this context means that a certain gap remains, so the plastic element does not need to be pressed into the space. For example, the plastic element can be a rectangular, square, or round rod, which, in the typical arrangement, maintains a distance of a few tenths of a millimeter from the respective battery modules. This allows for loose insertion or sliding of the plastic element, even within the usual manufacturing tolerances. This makes assembly very simple and efficient.In the event of a thermal event, this plastic element melts and seals the gap between the module housings and, if applicable, between the cell housings of the individual battery cells and the walls of the module housing. The plastic also provides insulating insulation to the end faces of the module housings. This prevents a short circuit from occurring, even if the electrically insulating coating on the cell connector is damaged. The plastic element can therefore reliably prevent a short circuit in this area.

[0015] According to a highly advantageous further development, the plastic element can be manufactured as a rod or strip from a suitable plastic material. This can be a solid material or a foamed material to save weight.

[0016] The module housing itself can, for example, consist of lateral strips that hold the individual battery cells of the battery module in position. In particular, these can be prismatic individual battery cells with a stable cell housing or a foil bag with a frame, which are stacked on top of each other. According to an advantageous embodiment, the plastic element then extends in the stacking direction between the battery modules and can, in particular, be longer than the module housing. It can thus project beyond the module housing in the stacking direction in order to reliably insulate all parts of the module housing from areas with any cell connectors.

[0017] In addition to the above-described design of the module housing with lateral elements such as sheet metal strips for fixing the individual battery cells, a trough-shaped module housing in which the individual battery cells are positioned accordingly would also be conceivable.

[0018] Further advantageous embodiments of the high-voltage battery according to the invention can also be seen from the exemplary embodiment, which is described in more detail below with reference to the figures.

[0019] This shows:

[0020] Fig. 1 shows a schematic cross-section through a part of a battery module according to the prior art; Fig. 2 shows the structure analogous to the representation in Fig. 1 in an embodiment according to the

[0021] invention; and

[0022] Fig. 3 shows a top view of a possible embodiment of a high-voltage battery according to the invention.

[0023] Figure 1 shows a schematic side view of a section of a high-voltage battery, designated 1 in its entirety, according to the prior art. On the far left, a portion of a prismatic battery cell 2 is depicted. This cell, together with many similar battery cells 2, forms a first battery module, designated 3. The battery cells 2 are stacked in a stacking direction that projects into the plane of the sheet and are located within a module housing 4, of which only one side wall is visible. Two such battery modules 3 are shown here by way of example, positioned adjacent to each other, leaving a small gap, designated 5, between the two module housings 4.

[0024] The module housings 4 are designed to be less high in a vertical direction h than the individual battery cells 2, so that a free space remains above the module housings 4 or their side walls.

[0025] Above this free space is a cell connector, designated 6, which connects two battery terminals, each designated 7, of individual battery cells 2 of the respective battery modules 3. To prevent a short circuit between the cell connector 6 and the grounded module housings 4, a lacquer layer, designated 8, is provided for the electrical insulation of the cell connector 6. This design functions very well unless a thermal event occurs within one of the battery modules 3. If this happens, hot gas from the individual battery cells 2 will flow through the free space between the two module housings 5 ​​and the cell connector 6, carrying with it, for example, glowing particles, liquid aluminum droplets, or other hot and abrasive substances.This can lead to the degradation or at least damage of the coating layer 8 within the high-voltage battery 1 in the event of such a so-called thermal event. In this case, an undesirable short circuit can occur between the cell connector 6 and the module housings 4, with these potential short-circuit paths indicated here by two jagged arrows 9. Such short circuits are highly undesirable because, due to the high energy content of the battery modules 3, they cause a further energy input into the high-voltage battery 1, which is already affected by a thermal event. They are therefore highly critical to safety.

[0026] To efficiently prevent such short circuits, the improved design shown in Figure 2 incorporates a plastic element 10, for example, a plastic rod made of solid or foamed plastic material, which is inserted into the cavity between the two module housings 4 and the cell connector 6. This plastic element 10 is dimensioned so that it lies loosely in this area during normal operation, i.e., it has a distance of, for example, a few tenths of a millimeter from the individual battery cells 2.

[0027] The plastic material is selected such that, in the event of a thermal event in the high-voltage battery 1, it melts, thereby sealing the gap 5, covering the upper edges of the module housings 4, and reliably sealing any gaps between the individual battery cells 2 and the module housing 4. This prevents the short-circuit paths shown in Figure 1 and labeled 9, even if the coating 8 deteriorates or is damaged. The plastic element 10 thus prevents the risk of additional short circuits in an exceptionally simple and efficient manner, thereby increasing the safety of such a high-voltage battery 1 in the event of a thermal event.

[0028] Finally, Figure 3 shows a top view of the assembly according to Figure 2. One of the battery modules 3 is shown at the top and the other at the bottom. Between the battery modules are the module housing parts 4 shown here, as well as the plastic element 10, which is located below the two cell connectors 6 indicated by way of example. It extends beyond the stacks of individual battery cells 2 forming each module in the stacking direction; only some of these cells are shown here, and only some are labeled with a reference numeral.

[0029] The structure of the two adjacent battery modules 3 of the high-voltage battery 1 shown here as a purely exemplary example can then be arranged in a battery housing (not shown).

Claims

Patent claims 1. High-voltage battery (1) with at least two adjacent battery modules (3) which are electrically contacted together, wherein the battery modules (3) each have a module housing (4) lying on ground which is less high than the individual battery cells (2) of the battery modules (3), and wherein the electrical contacting (6) between the battery modules (3) is arranged above the module housings (4), characterized in that a plastic element (10) is arranged between the upper edges of the adjacent module housings (4) and the electrical contacting (6) between the battery modules (3).

2. High-voltage battery (1) according to claim 1, characterized in that the electrical contact (6) is electrically insulated by means of a varnish (8).

3. High-voltage battery (1) according to claim 1 or 2, characterized in that the material of the plastic element (10) is selected such that it melts in the event of a thermal event in at least one of the battery modules (3).

4. High-voltage battery (1) according to one of claims 1 to 3, characterized in that the plastic element (10) is designed as a rod or strip.

5. High-voltage battery (1) according to one of the preceding claims, characterized in that the plastic element (10) is solid or foamed.

6. High-voltage battery (1) according to one of the preceding claims, characterized in that the plastic element (10) is loosely inserted between the battery modules (3).

7. High-voltage battery (1) according to one of the preceding claims, characterized in that each of the battery modules (3) has a stack of prismatic battery individual cells (2).

8. High-voltage battery (1) according to claim 7, characterized in that the plastic element (10) extends in the stacking direction (s).

9. High-voltage battery (1) according to one of the preceding claims, characterized in that the plastic element (10) is longer than the module housings (4).

10. High-voltage battery (1) according to one of the preceding claims, characterized in that at least one of the module housings (4) is designed in a trough shape.

Images