Battery module

Abstract

The present invention relates to a battery module (1) comprising a plurality of battery cells (2) and a cell connector (3) that electrically connects a battery electrode (6) of one of the battery cells (2) to a battery electrode (7) of an adjacent battery cell (2), wherein each battery cell (2) has an exhaust region (5) weakened by a predetermined break point (4) in its cell housing, and one of the battery electrodes (6) is arranged in the exhaust region (5). The battery module according to the invention is characterized by having at least one flow guiding element (12) surrounding at least a portion of the circumference of the exhaust region (5) and configured to block or at least disperse exhaust gas from the adjacent battery cells (2), wherein the cell connector (3) extends to the battery electrode (6) arranged in the exhaust region (5) via the circumferential portion excluding one or more flow guiding elements (12).

Description

Technical Field

[0001] The present invention relates to a battery module of the type defined in more detail in the preamble of claim 1, comprising a plurality of battery cells and having a cell connector for electrically connecting the battery electrode of one of the battery cells to the battery electrodes of adjacent battery cells. Background Technology

[0002] Battery modules comprising multiple individual battery cells are known in the art, and these cells are electrically connected via cell connectors. Furthermore, for battery cells employing lithium-ion technology, so-called vents are typically provided. This can be an overpressure valve, or in most cases simply a predetermined break point in the cell casing area. If overpressure occurs inside a battery cell, the vent will open, or possibly the vent valve will open, thereby releasing the overpressure. Hot gases escape here, often carrying sparks, incandescent particles, etc. If these vented gases then directly enter the area of ​​adjacent battery cells, they will correspondingly heat those cells and cause thermal reactions in those adjacent cells as well. This can ultimately lead to a thermal cascade reaction and cause "thermal runaway" of the entire battery module. In this paper, this is also referred to as thermal propagation.

[0003] This is particularly problematic if one of the battery electrodes is located within the venting area. This typically occurs with round cells, but is not limited to them. Because of the contact with the cell connector (which usually leads to the battery electrode from one side), the venting area, when opened, partially opens in only one direction, like a hinged lid. All the gas generated inside the cell casing then flows out through this opening. Thus, it is directed in a preferential direction with almost full volumetric flow, causing adjacent battery cells in that direction to be correspondingly heated intensely and thus endangered.

[0004] DE 10 2013 213 877 A1 therefore describes a battery system in which the battery casing is spatially divided into two regions by a hermetically designed separator. Here, each individual battery cell is partially arranged in the first region and partially in the second region, specifically in that the vent of the individual battery cell extends into the second region. Therefore, any potentially released gas only enters the second region, which is sealed relative to the first region. This avoids the danger of a chain reaction, but the battery casing is very complex because it must be divided into two hermetically separated separate casings, and because the penetration point of the individual battery cell through the separator must be reliably sealed.

[0005] Conversely, the solution in WO 2023 / 003 260 A1 provides a separator frame that isolates individual battery cells from each other in the vent area. The separator frame has notches through which cell connectors, implemented as busbars, are guided to the cell electrodes.

[0006] US 2021 / 0 104 718 A1 describes a similar frame with integrated cell connectors that are mounted on individual battery cells.

[0007] For more information on existing technologies, see US 2009 / 0 111 015 A1. Summary of the Invention

[0008] Therefore, the object of the present invention is to provide an improved battery module according to the preamble of the main claim, wherein the risk of thermal damage to adjacent battery cells during the release of exhaust gases is minimized in a simple and efficient manner.

[0009] According to the invention, this objective is achieved by a battery module having the features of claim 1 (particularly in the characterizing portion of claim 1). Advantageous designs and improvements are given in the dependent claims.

[0010] The battery module according to the invention is constructed such that one of the battery electrodes is arranged in a venting region weakened relative to the rest of the cell housing. According to the invention, at least one guiding element is provided, which surrounds a portion of the circumference of the venting region and is configured to block or at least disperse venting gases from adjacent battery cells, i.e., distribute them over a larger volume area. This minimizes heat input to adjacent battery cells located in this direction. Further, in the battery module according to the invention, the cell connector then leads to the battery electrode arranged in the venting region via a circumferential portion without the guiding element. Therefore, the guiding element is preferably arranged in a region where the cell connector does not extend into the venting region to contact the battery electrode. In the event of venting, the venting region typically opens away from the side where the cell connector is introduced. Therefore, the venting gas flows in the direction of the guiding element, which causes the venting gas to be dispersed or deflected, thereby providing thermal protection to the adjacent battery cells at that location.

[0011] According to the invention, the cell connector includes a first contact area for connection with a battery electrode within a venting region and a second contact area for connection with another battery electrode of an adjacent battery cell. These two contact areas are connected to each other by a connecting strip, wherein the first contact area is formed at one end of the connecting strip and can be, for example, simply implemented as a trapezoidal or square connecting strip with rounded corners. Further, the second contact area is designed to partially surround the venting region of the battery cell to be contacted in the circumferential direction. Therefore, the second contact area can be designed, for example, as a C-shape, semi-circle, or similar shape to at least partially surround the venting region. According to the invention, at least one flow guiding element is constructed as part of the second contact area. This arrangement, in which the contact area at least partially surrounds the venting region in the circumferential direction, allows for an integrally constructed flow guiding element also arranged in the region along with the second contact area. In the simplest flange case, the contact area can simply be implemented as an upward bend at its end facing the venting region. Corresponding flow guiding pins, rods, grilles, or the like can also be arranged here.

[0012] Here, the at least one guiding element can be arranged to surround more than half of the circumference of the exhaust region. For example, two-thirds of the circumference is ideal, so that exhaust gas can be reliably diverted from adjacent battery cells.

[0013] Furthermore, another highly advantageous design is that the at least one flow-guiding element is constructed as a plane substantially perpendicular to the exhaust region. This reliably disperses the exhaust gas, or preferably deflects it perpendicularly from the exhaust surface, and thus perpendicularly from the individual battery cells of the battery module. In this way, the exhaust gas will not, or at least will not, enter the critical areas of adjacent battery cells before being adequately cooled.

[0014] Here, another highly advantageous design of the battery module according to the invention is that the at least one current-guiding element is constructed as part of the cell housing and / or the battery housing. Therefore, the current-guiding element can be fully or partially mounted on the cell housing, or it can be integrally formed from the material of the cell housing. Here, the current-guiding element can interact with corresponding mating elements of the battery housing, or it can be formed solely by corresponding elements of the battery housing extending into the region of the cell housing, making the desired effect possible.

[0015] As described above, the at least one flow guiding element can be constructed in the form of a separate rod or grid. The airflow is then dispersed, thereby accelerating its cooling and distributing the gas concentration, and thus the gas's thermal energy content concentration, over a larger area.

[0016] As an alternative, according to another highly advantageous design, the at least one flow guiding element can be constructed in the form of a flange. Unlike a rod or grille, this flange is a continuous flow guiding element made of a strip of material, which preferably stands upright in the area of ​​the cell housing so that the outflowing exhaust gas approaches from the side and is accordingly guided upward.

[0017] According to a highly advantageous improvement, the flange can be integrated into the cell connector as part of its design. Integrating this flange as a current-guiding element into the cell connector is particularly simple and efficient. Integration into the cell connector (which is feasible not only in the case of flanges but also, in principle, in the case of rods or grids) achieves an extremely simple structure that can also be effectively used for conventional battery cells. Only minor adjustments to the cell connector are required, which is significantly easier to implement and execute compared to correspondingly altering the cell housing of the battery cell.

[0018] Here, according to a very advantageous improvement, the second contact area itself can be constructed in a C-shape, wherein the connecting strip is arranged on the side opposite to the opening of the C-shape, so that the C-shape can correspondingly surround the exhaust area from the connecting strip.

[0019] Here, the use of at least one current-guiding element, or according to a particularly advantageous design of a cell connector incorporating an integrated current-guiding element, can be applied to any type of battery cell. Thus, the battery can be, for example, a prismatic battery cell. However, when the battery cell is constructed as a cylinder, this structure has particular advantages, as is the case with a very advantageous battery module design according to the invention. Such a circular cell can have a venting region containing a first battery electrode at the center of one end face, wherein the cell housing itself constitutes a second battery electrode, so that the second contact area of ​​the cell connector can be mounted at any position on the cell housing. It is particularly advantageous if the cell connector is constructed to include a C-shaped portion (e.g., with an upright flange) and arranged around the venting region of a battery cell. Then, the connecting strip containing the second contact area can extend through the empty portion of the circumference of the adjacent cell connector to the battery electrode of the adjacent battery cell located within the venting region. Attached Figure Description

[0020] Other advantageous designs of the battery module according to the invention are also derived from the embodiments described in more detail below with reference to the accompanying drawings.

[0021] in: Figure 1 An exemplary battery module with a structure according to the prior art is shown; Figure 2 It shows according to Figure 1The battery module, in which the venting area of ​​the middle battery cell has been opened; Figure 3 The design of the battery module according to the present invention is shown; and Figure 4 It shows according to Figure 3 The design scheme of the battery module has opened the venting area of ​​the middle battery cell. Detailed Implementation

[0022] exist Figure 1 The diagram shows a battery module, generally labeled 1. Here, a portion of battery module 1 shown includes seven individual battery cells, each labeled 2. Some of these individual battery cells 2 are electrically connected to each other via cell connectors labeled 3; here, three of the individual battery cells 2 are connected in series, purely illustratively. The cylindrical cell housing of each battery cell 2, configured as a circular cell, has a predetermined break point 4 on its upper end face, indicated only by reference numerals on the rear-middle portion of the battery cell 2 (cell connector 3 not shown). Within this predetermined break point 4 is a venting region labeled 5, which opens in the event of overpressure inside the battery cell 2 to release the gas causing the overpressure. At the center of this venting region 5 is one of the battery electrodes 6, typically the positive electrode. The outer annular portion of the cell housing surrounding the venting region 5 forms another electrode 7, typically the negative electrode.

[0023] Each cell connector 3 includes a first contact area 8 for electrical contact with the first battery electrode 6, and a corresponding second contact area 9 for contact with the battery electrode 7. Here, the second contact area 9 is substantially C-shaped and surrounds approximately two-thirds of the circumference of the venting area 5. The first contact area 8 and the second contact area 9 are interconnected by a connecting strip labeled 10, one end of which directly constitutes the contact area 8.

[0024] exist Figure 2 The same structure is presented again in the illustration using the same markings. Unlike... Figure 1As shown in the diagram, the venting region 5 of the middle battery cell 2 is open, exposing the vent marked 11. Due to the contact between the battery electrode 6 arranged within the venting region 5 and the first contact area 8 of the cell connector 3, the vent 11 is primarily formed on the side of the venting region 5 away from the inlet side of the connecting strip 10, mainly on the left side. Accordingly, all vented gases are discharged from the vent 11 to the left or in the main flow direction to the left. The battery cell 2 shown in the middle on the left, as well as the battery cells 2 shown in the middle on the left rear and front, receive most of the vented gases and thus the heat energy contained therein. Therefore, these battery cells 2 are subjected to particularly high loads, creating an imminent danger of thermal events occurring in these battery cells 2, causing their venting regions to open and vented gases to flow out there as well. In the worst case, this could lead to a thermal cascade, i.e., the battery module 1 or the high-voltage battery composed of such battery modules 1 experiencing so-called "thermal runaway."

[0025] To prevent this situation in a simple and efficient manner, a current-guiding element 12 is provided in the design of the battery module 1 according to the present invention. Figure 3 and Figure 4 This is illustrated in the diagram with a particularly efficient embodiment as an example. Figure 3 The structure of battery module 1 shown in the figure is similar to... Figure 1 The embodiment shown is exactly the same, the only difference being that a flow guide element 12 in the form of a flange 12 is provided here. Hereinafter, the term flange 12 will be used only for the flow guide element 12, as only this type is shown in the selected embodiment. Of course, other forms are conceivable, such as individual upright elements, grilles, etc.

[0026] The flange 12 is constructed as part of the battery cell connector 3, and specifically constitutes part of the second contact area 9. It is implemented as an upwardly bent area, surrounding more than half of the circumference of the vent area 5, thus leaving only a portion of the circumference exposed through which the connecting strip 10 of the adjacent battery cell connector 3 can extend. At this point, if the vent 11 opens again (which is related to...), Figure 2 Similar diagrams, such as Figure 4 As shown in the diagram for the middle battery cell 2, the exhaust gas discharged from the exhaust port 11 is directed upwards, as indicated by the arrow here again. Therefore, the exhaust gas is diverted from the adjacent battery cells 2, effectively preventing them from being heated by the exhaust gas. This structure, which employs an upward diversion method as shown here, can also be adapted to a lateral or reverse method, allowing the exhaust gas to be diverted downwards, and, for example, guided from at least one battery casing surrounding the battery module 1 through a known exhaust channel.

Claims

1. A battery module (1) comprising a plurality of individual battery cells (2) and a cell connector (3), wherein the cell connector (3) electrically connects the battery electrode (6) of one of the individual battery cells (2) to the battery electrode (7) of an adjacent individual battery cell (2), wherein, Each battery cell (2) has an exhaust region (5) weakened by a predetermined break point (4) in its cell housing, in which one of the battery electrodes (6) is arranged, wherein at least one flow guiding element (12) is provided, the flow guiding element (12) surrounding at least a portion of the circumference of the exhaust region (5) and configured to block or at least disperse exhaust gas from adjacent battery cells (2), wherein the cell connector (3) extends through a portion of the circumference excluding the flow guiding element (12) to the battery electrode (6) arranged in the exhaust region (5), and wherein the cell connector (3) has a first contact area (8) for connecting with the battery electrode (6) in the exhaust region (5) and a second contact area (9) for connecting with another battery electrode (7) of an adjacent battery cell (2). Its features are, The contact areas (8, 9) are connected by a connecting strip (10), wherein the first contact area (8) is formed by one end of the connecting strip (10), and wherein the second contact area (9) is constructed such that it at least partially surrounds the exhaust area (5) of the battery cell to be contacted in the circumferential direction, and wherein the at least one flow guiding element (12) is constructed as part of the second contact area (9).

2. The battery module (1) according to claim 1. Its features are, The at least one flow guide element (12) surrounds more than half of the circumference of the exhaust region (5).

3. The battery module (1) according to claim 1 or 2. Its features are, The at least one flow guiding element (12) is configured as a plane that is substantially perpendicular to the exhaust region (5).

4. The battery module (1) according to any one of claims 1 to 3. Its features are, The at least one flow guiding element (12) is constructed in the form of a single rod or a grid.

5. The battery module (1) according to any one of claims 1 to 3. Its features are, The at least one flow guiding element (12) is constructed in the form of a flange.

6. The battery module (1) according to any one of claims 1 to 5. Its features are, The at least one current-conducting element (12) is configured as part of the cell housing and / or part of the battery housing.

7. The battery module (1) according to any one of claims 1 to 5. Its features are, The at least one current-conducting element (12) is constructed as part of the cell connector (3) and is integrated with it.

8. The system (1) according to any one of claims 1 to 7. Its features are, The second contact area (9) is constructed in a C-shape.

9. The battery module (1) according to any one of claims 1 to 8. Its features The battery cell (2) has a cylindrical design, with its exhaust area (5) and the first battery electrode (6) arranged in the center of one end face, wherein the cell casing constitutes the second battery electrode (7).

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