Simplified assembly of the ruptured membrane through reinforcement.

Abstract

The present invention relates to a membrane arrangement comprising a rupture membrane and at least one reinforcing frame, wherein the reinforcing frame is connected to the rupture membrane, and the reinforcing frame connected to the rupture membrane is inserted into the cell housing internally and connected to the cell housing externally by a thermal bonding process. The present invention also relates to a method for connecting a rupture membrane to a battery cell housing and a battery cell having the membrane arrangement.

Description

Technical Field

[0001] The present invention relates to a membrane arrangement including a rupture membrane and at least one reinforcing frame. Further, the present invention relates to a method of connecting a rupture membrane to a cell housing of a battery cell and a battery cell having the membrane arrangement.

Background Art

[0002] Electrochemical storage devices such as lithium-ion batteries can release gas components under certain circumstances and thus accumulate overpressure within the cell housing. Excessive pressure within the battery cell housing or inside the cell housing can pose a risk of explosion. Battery cells having an integrated predetermined breaking point are already known. For example, in order to avoid dangerous overpressure, a predetermined breaking point can be incorporated into the wall of the battery cell housing in the form of a punch hole.

[0003] Furthermore, rupture membranes connected to the outside of the housing cover of a battery cell are already known. However, the problem of connecting the rupture membrane outside, especially by welding, is that a certain material thickness is required in order to enable a reliable connection of the rupture membrane to the corresponding part of the battery cell. For this reason, in order to avoid this problem, the rupture membrane is mainly arranged within a cell cover having a sufficient material thickness. The cell cover usually forms the uppermost part of the battery cell and also has an electrical connection. However, depending on the arrangement and orientation of the cell stack, the generated gas is either insufficiently dissipated through the cell cover or not dissipated at all. Furthermore, the electrical connection can impair the formation of a gas channel for removing gas from the battery cell. In particular, in order to enable a controlled discharge of gas components from a battery system having a plurality of battery cells, the rupture membrane incorporated into the cell cover has to be gas-tightly coupled to an external channel with additional effort.

Summary of the Invention

[0004] Accordingly, the present invention aims to create a method for arranging and connecting ruptured membranes that enables technically simple positioning of the ruptured membrane in the bottom region of a cell housing, particularly an extruded or stretched cell housing. This objective is achieved by the features described in claim 1. Further advantageous embodiments of the present invention are part of the subordinate claims.

[0005] A membrane arrangement is provided according to one aspect of the present invention. The membrane arrangement comprises a rupture membrane and at least one reinforcing frame connected to the rupture membrane. According to the present invention, the reinforcing frame connected to the rupture membrane is arranged such that its inner side is inserted into a battery cell housing or cell housing and its outer side is connected to the cell housing by a thermal bonding process.

[0006] A battery cell is provided according to a further aspect of the present invention. The battery cell has a cell housing having at least one cell stack arranged in the internal volume of the cell housing. Furthermore, the battery cell has at least one membrane arrangement according to the present invention. Advantageously, the membrane arrangement is located in the bottom region of the cell housing.

[0007] This allows for the connection of the rupture membrane to a battery cell housing, particularly a thin-walled one, in two steps. This measure also allows for the placement of the rupture membrane in any region of the cell housing, especially the bottom region of the battery cell. In the first step, the rupture membrane is connected to a reinforcing frame. This step can be performed using friction-fit and / or material-fit and / or shape-fit connections. For example, the rupture membrane can be welded to the reinforcing frame. The resulting placement can then be inserted into an opening provided for this purpose, or positioned within such an opening in the cell housing. The additional material thickness formed by the reinforcing frame can then be used to connect the rupture membrane to the cell housing in the second step.

[0008] The rupture membrane can be welded to the cell housing wall via a reinforcing frame. The additional material thickness of the reinforcing frame allows for a process-reliable connection of any rupture membrane, eliminating the need for separate fabrication of the rupture membrane as part of the battery cell manufacturing process.

[0009] By using a reinforcing frame, joints such as welded seams can be placed in areas of the cell housing that do not serve any other function. This means, for example, that the sealing surface or outer surface of the cell housing to which the sealant is applied can be kept free of joints or welded seams, especially in order to achieve the most optimal sealing effect.

[0010] In another embodiment, the rupture membrane is plate-shaped. Advantageously, the rupture membrane is connected to the reinforcing frame by being placed on the edge of the reinforcing frame or inserted into a recess of the reinforcing frame. This measure allows the rupture membrane to be connected to the reinforcing frame in a particularly versatile manner.

[0011] Joining methods such as laser welding, ultrasonic welding, and soldering can be used to join the ruptured membrane to the reinforcing frame. Advantageously, at least one first joining connection can be introduced to connect the ruptured membrane to the reinforcing frame by a material bond. Such a first joining connection may take the form of, for example, a surrounding welded joint.

[0012] Next, the membrane arrangement may be connected to a portion or wall of the cell housing using at least one second bonding connection.

[0013] In this case, the first joint connection may be offset from the second joint connection in at least some area. As a result, the openings of the cell housing and the rupture membrane can have different sizes, increasing the selection of usable rupture membranes.

[0014] When the reinforcing frame is designed as a perimeter reinforcing frame, the rupture membrane can be mechanically supported optimally. Advantageously, the reinforcing frame is bonded to the rupture membrane along its entire circumference. This ensures a liquid-tight connection between the rupture membrane and the reinforcing frame.

[0015] In a further embodiment, the reinforcing frame has at least one positioning pin. The reinforcing frame connected to the ruptured membrane can be aligned with the opening of the cell housing by at least one positioning pin. Advantageously, at least one positioning pin protrudes at least partially into the opening of the cell housing. The use of positioning pins allows for easier assembly of the membrane arrangement and precise alignment of the membrane arrangement with respect to the opening of the cell housing.

[0016] When the positioning pins are designed as perimeter positioning pins, the alignment of the film arrangement can be particularly precise. Furthermore, the perimeter positioning pins are inserted into the opening and shaped to extend parallel to the edge contour of the opening in the cell housing. This measure allows at least one second bonding connection to extend along the contour of the opening in the cell housing, thus connecting the opening contour to the positioning pins by material bonding. This allows the reinforcing frame to be connected to the cell housing in a particularly process-reliable manner. The course of the positioning pins parallel to the opening contour allows for particularly optimal tool access for inserting the second bonding connection.

[0017] If at least one reinforcing cage is placed on the reinforcing frame, the membrane arrangement can be further hardened or structurally reinforced.

[0018] In further embodiments, at least one reinforcing cage is positioned inside the cell housing or outside the cell housing on a reinforcing frame. Positioning the reinforcing cage inside the cell housing can effectively prevent blockage of the area in front of the rupture membrane, thus ensuring that the rupture membrane protection mechanism is always reliable. Similarly, positioning the reinforcing cage outside the cell housing can be used to ensure that gaseous components of the battery cell can be reliably released if overpressure occurs through the rupture membrane, and to maintain openness in the outer area of ​​the cell housing.

[0019] If the reinforcing frame connected to the ruptured membrane is configured to be connected to the outside of the cell housing directly or indirectly via at least one reinforcing cage using a thermal bonding process, then at least one reinforcing cage can be connected to the reinforcing frame particularly efficiently. This allows a bonding connection, such as a welded joint, to be made across the area of ​​the reinforcing cage, enabling the reinforcing frame to be connected to the cell housing simultaneously.

[0020] In an example of a further embodiment, the reinforcing frame has at least one edge bevel and / or stall edge. The edge bevel may allow particularly optimal aerodynamics for the flow out through the actuated or ruptured membrane. The use of a stall edge may be used to convert the flow from the battery cell resulting from overpressure from a laminar flow state into a turbulent state, thereby increasing the flow velocity and allowing the overpressure to decrease more rapidly.

[0021] A further aspect of the present invention provides a method for connecting a rupture membrane to a battery cell housing. In one step, the rupture membrane is aligned with a reinforcing frame and connected to the reinforcing frame with a material bond. In a further step, the reinforcing frame connected to the rupture membrane is positioned inside the internal volume of the cell housing at the opening of the cell housing. The reinforcing frame is then bonded to the cell housing by applying a thermal bonding process to the outside of the cell housing in the region of the opening.

[0022] The method according to the present invention ensures optimal tool access to the corresponding joint connections during the application of the joining method. In particular, the method avoids the introduction of weld seams from the inside of the cell housing, along with the resulting need for particularly small or narrow tools. The method enables joining of each component by introducing the joint connections to an external surface, such as the outward contour of the opening of the cell housing.

[0023] According to one embodiment, the reinforcing frame is joined to the cell housing by a thermal joining process in the form of laser welding, soldering, contact welding or thermally activated bonding. As a result, the introduction of the first joining connection and / or the second joining connection can be flexibly realized using different tools or joining processes.

[0024] In particular, when the reinforcing frame connected to the rupture membrane is positioned inside the internal volume of the cell housing using at least one positioning pin at the opening of the cell housing, the membrane arrangement can be technically easily inserted into the cell housing. In particular, when the positioning pin is arranged adjacent to the edge contour of the opening of the cell housing, the membrane arrangement is inserted into the opening of the cell housing and can optionally be latched to the opening. In this way, when the membrane arrangement is connected to the cell housing by a material bond, subsequent slippage of the membrane arrangement can be avoided.

[0025] According to an example of a further embodiment, the reinforcing frame is connected to the cell housing by inserting at least one weld seam into the region between at least one positioning pin and the edge contour of the opening of the cell housing. This measure enables the region between the edge contour of the opening and the positioning pin to be reliably connected by inserting a weld seam. In such a connection, the requirements for the accuracy of tool guidance are relatively low, so such a connection is particularly quick and easy to implement technically.

Brief Description of the Drawings

[0026] Hereinafter, some example embodiments of the present invention will be described in more detail with reference to the drawings. These show [Figure 1] FIG. 1 is a schematic cross-sectional view of a membrane arrangement according to one embodiment of the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view of the bottom side region of a cell housing of a battery cell into which the membrane arrangement from FIG. 1 is inserted. [Figure 3]FIG. 3 is a schematic cross-sectional view of the bottom side region of a cell housing having a membrane arrangement according to a second embodiment of the present invention. [Figure 4] FIG. 4 is a schematic cross-sectional view of the bottom side region of a cell housing having a membrane arrangement according to a third embodiment of the present invention. [Figure 5] FIG. 5 is a schematic cross-sectional view of the bottom side region of a cell housing having a membrane arrangement according to a fourth embodiment of the present invention. [Figure 6] FIG. 6 is a schematic cross-sectional view of the bottom side region of a cell housing having a membrane arrangement according to a fifth embodiment of the present invention. [Figure 7] FIG. 7 is a schematic cross-sectional view of the bottom side region of a cell housing having a membrane arrangement according to a sixth embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In the figures, the same reference numerals indicate the same elements or components. The sizes and relative positions of the elements in the figures are not necessarily drawn to an exact scale, and some of these elements are enlarged and positioned for clarity. Further, the particular shapes of the drawn elements are not intended to convey information regarding the actual shapes of the individual elements, but are selected only to facilitate recognition in the figures.

[0028] FIG. 1 shows a schematic cross-sectional view of a membrane arrangement 10 according to one embodiment of the present invention. In the example of the embodiment shown, the membrane arrangement 10 has a rupture membrane 11 and a reinforcing frame 12. The cross-sectional view serves to illustrate the extension of the membrane arrangement 10 along the width direction B and the height direction H.

[0029] The reinforcing frame 12 is connected to the rupture membrane 11 by a material bond. For this purpose, a first joint connection 21 creating a material-bonded joint connection between the reinforcing frame 12 and the rupture membrane 11 is introduced through the rupture membrane 11. The arrows illustrate the direction of action by a tool, not shown, such as a laser welding tool. The first joint connection 21 can be designed, for example, as a circumferential weld seam.

[0030] The reinforcing frame 12 is designed as a perimeter frame and has a centrally located recess 13, which allows the rupture membrane 11 to rupture or fold into the recess 13 in the event of an overpressure event.

[0031] The reinforcing frame 12 connected to the ruptured membrane 11 is designed to be inserted into the battery cell housing or cell housing 30 on the inside and connected to the cell housing 30 on the outside by a thermal bonding process (see Figure 2).

[0032] The reinforcing frame 12 has, for example, positioning pins 14. The reinforcing frame 12 connected to the ruptured membrane 11 can be aligned by the positioning pins 14 to the opening 33 of the cell housing 30 shown in Figure 2. The positioning pins 14 protrude into the opening 33 of the cell housing 30.

[0033] The positioning pin 14 has a circumferential or annular shape and surrounds the recess 13 of the reinforcing frame 12 on its outer circumference. When inserted into the opening 33 of the cell housing 30, the positioning pin 14 is shaped to extend parallel to the edge contour of the opening 33 of the cell housing 30, or to extend along this contour of the opening 33.

[0034] Figure 2 shows a schematic cross-sectional view of the bottom region 31 or bottom of the cell housing 30 of the battery cell 100 having the membrane arrangement 10 inserted from Figure 1. For clarity, other components of the battery cell 100, such as the cell stack, cell connector, battery terminals, and electrolyte, are not shown.

[0035] The membrane arrangement 10 is positioned in the bottom region 31 such that positioning pins 14, which are molded as positioning rings, protrude in the positive direction into the opening 33. Preferably, the entire reinforcing frame 12 is placed flat and flush with the inside of the bottom region 31.

[0036] The opening 33 may have a circular, elliptical, rectangular, or similar cross-section. The membrane arrangement 10 reinforces the bottom region 31 of the cell housing 30. The membrane arrangement 10 is connected to the bottom region 31 of the cell housing 30 by a second periphery joint connection 22. The second joint connection 22 is typically designed as a welded seam.

[0037] The arrows in Figure 2 illustrate the effect of an external joining tool, such as a laser welding tool, on the surrounding gap between the positioning pin 14 and the contour of the opening 33 of the cell housing 30.

[0038] In the illustrated embodiment, the reinforcing frame 12 protrudes to the side wall 32 of the cell housing 30, and thus hardens the bottom side of the cell housing 30.

[0039] Figure 3 shows a schematic cross-sectional view of the bottom region 31 of a cell housing 30 having a membrane arrangement 10 according to a second embodiment of the present invention. In contrast to the embodiment shown in Figure 2, here the membrane arrangement 10 has additional structural curing material in the form of a reinforcing cage 40.

[0040] The reinforcing cage 40 surrounds the ruptured membrane 11 on the outside, allowing free flow into the ruptured membrane 11 within the internal volume V of the cell housing 30.

[0041] In an alternative or additional embodiment shown in Figure 4, the membrane arrangement 10 has a reinforcing cage 40 connected to the outside of the reinforcing frame 12. Thus, the area outside the internal volume V of the cell housing 30 is kept open by the reinforcing cage 40.

[0042] Furthermore, the reinforcing cage 40 allows for further reinforcement of the ruptured membrane 11 and the reinforcing frame 12.

[0043] In Figure 4, the reinforcing frame 12 connected to the ruptured membrane 11 is also directly connected to the outside of the cell housing 30 via the reinforcing cage 40. In this way, a second joint connection 22, such as a welded seam, can be introduced through a region or portion of the reinforcing cage 40, and at the same time, the reinforcing frame 40, in addition to the reinforcing frame 12, is also connected to the cell housing 30.

[0044] Figure 5 shows a schematic cross-sectional view of the bottom region 31 of a cell housing 30 having a membrane arrangement 10 according to a fourth embodiment of the present invention. In contrast to the figures already described, this cross-sectional view shows an extension of the membrane arrangement 10 along the longitudinal direction L.

[0045] To enable particularly efficient reinforcement or hardening of the bottom region 31, the reinforcing frame 12 protrudes beyond the opening 33 on one side and extends substantially along the extension of the cell housing 30 in the longitudinal direction L, spanning the entire bottom region 31 of the cell housing 30.

[0046] For clarity, joint connections 21 and 22 are not shown in Figures 5, 6, and 7.

[0047] Figure 6 shows a schematic cross-sectional view of the bottom region 31 of a cell housing 30 having a membrane arrangement 10 according to a fifth embodiment of the present invention. In this embodiment, the reinforcing frame 12 has at least one edge bevel 41.

[0048] Such a veranda slope 41 can improve the aerodynamics of the flow flowing out through a rupture membrane 11 that is activated or ruptured by overpressure. The flow may have gaseous and liquid components of electrolytes, as illustrated by arrows.

[0049] A further membrane arrangement 10 having a reinforcing frame 12 is illustrated according to the sixth embodiment shown in Figure 7. The reinforcing frame 12 has a stall edge 42.

[0050] The stall edge 42 is essentially perpendicular to the bottom region 31 and therefore protrudes into the internal volume V of the cell housing 30. Depending on the configuration, the stall edge 42 may be positioned on the edge of the reinforcing frame 12 in the longitudinal direction L to force a stall in the resulting turbulence when flow occurs.

[0051] Similar to Figure 6, the flow arises from the activation or rupture of the rupture membrane 11 due to the pressure exceeding a predetermined level in the internal volume V of the cell housing 30. Therefore, the flow consists of a component leaking from the cell housing 30, as illustrated by the arrows.

Claims

1. A membrane arrangement (10) having a rupture membrane (11) and at least one reinforcing frame (12), wherein the reinforcing frame (12) is connected to the rupture membrane (11), characterized in that the reinforcing frame (12) connected to the rupture membrane (11) is designed to be inserted into a cell housing (30) on the inside and connected to the cell housing (30) of a battery cell (100) on the outside by a thermal bonding process.

2. The membrane arrangement according to claim 1, wherein the rupture membrane (11) is in the form of a plate, and the rupture membrane (11) is placed on the edge of the reinforcing frame (12) or placed in a recess of the reinforcing frame (12) and connected to the reinforcing frame (12).

3. The membrane arrangement according to claim 1 or 2, wherein the reinforcing frame (12) is designed as a periphery reinforcing frame (12), and the reinforcing frame (12) is connected to the ruptured membrane (11) along its entire circumference in a material-fixing manner.

4. The membrane arrangement according to any one of claims 1 to 3, wherein the reinforcing frame (12) has at least one positioning pin (14), and the reinforcing frame (12) connected to the ruptured membrane (11) can be aligned with the opening (33) of the cell housing (30) by the at least one positioning pin (14), and the at least one positioning pin (14) protrudes at least partially into the opening (33) of the cell housing (30).

5. The membrane arrangement according to claim 4, wherein the positioning pin (14) is designed as a periphery positioning pin (14) and is shaped to extend parallel to the edge contour of the opening (33) of the cell housing (30) when the periphery positioning pin (14) is inserted into the opening (33).

6. The membrane arrangement according to any one of claims 1 to 5, wherein at least one reinforcing cage (40) is placed on the reinforcing frame (12).

7. The membrane arrangement according to claim 6, wherein at least one reinforcing cage (40) is positioned inside or outside the cell housing (30) on the reinforcing frame (12).

8. The membrane arrangement according to claim 6 or 7, wherein the reinforcing frame (12) connected to the ruptured membrane (11) is designed to be connected externally to the cell housing (30) directly or indirectly via at least one reinforcing cage (40) by a thermal bonding process.

9. The film arrangement according to any one of claims 1 to 8, wherein the reinforcing frame (12) has at least one edge bevel (41) and / or stall edge (42).

10. A method for connecting a rupture membrane (11) to a cell housing (30), particularly a cell housing (30) of a battery cell (100), wherein the rupture membrane (11) is aligned with a reinforcing frame (12) and connected to the reinforcing frame (12) in a material-fixed manner, the reinforcing frame (12) connected to the rupture membrane (11) is positioned inside the internal volume (V) of the cell housing (30) at an opening (33) of the cell housing (30), and the reinforcing frame (12) is joined to the cell housing (30) in a material-fixed manner by applying a thermal bonding process outside the cell housing (30) in the region of the opening (33).

11. The method according to claim 10, wherein the reinforcing frame (12) is joined to the cell housing (30) in a material-fixing manner by a thermal joining method configured as laser welding, soldering, contact welding, or thermal activation bonding.

12. The method according to claim 10 or 11, wherein the reinforcing frame (12) connected to the ruptured membrane (11) is positioned inside the internal volume (V) of the cell housing (30) at the opening (33) of the cell housing (30) using at least one positioning pin (14), and the positioning pin (14) is positioned adjacent to the edge contour of the opening (33) of the cell housing (30).

13. The method according to claim 12, wherein the reinforcing frame (12) is connected to the cell housing (30) by introducing at least one welded joint in the region between the at least one positioning pin (14) and the edge contour of the opening (33) of the cell housing (30).

14. A battery cell (100) comprising a cell housing (30) having at least one cell stack disposed within the internal volume (V) of the cell housing (30), comprising a membrane arrangement (10) according to any one of claims 1 to 9, wherein the membrane arrangement (10) is disposed in the bottom region (31) of the cell housing (30).

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