Gasket for an electrical energy store, electrical energy store, arrangement system and motor vehicle

Abstract

The invention relates to a gasket (1) for a mechanical connection (11) between an energy storage module (3) and a housing (4) for an electrical energy store (2) of a motor vehicle, the gasket (1) having an axial bore (17) for receiving a connecting means (10) of the mechanical connection (11) and axially opposite abutment surfaces (9a, 9b) for pressing against metal contact surfaces (7, 8) of the energy storage module (4) and of the housing (4). The gasket (1) has a metal bushing (12) for providing a current path (16) between the contact surfaces (7, 8) for potential equalization between the energy storage module (3) and the housing (4), axially opposite end surfaces (13a, 13b) of the metal bushing forming the abutment surfaces (9a, 9b) and the metal bushing having a cross-sectional narrowing (15) between the end surfaces (13a, 13b) forming a fuse (18) for interrupting the current path (16) in the event of an overcurrent. Furthermore, the gasket (1) has a thermally insulating material (19) surrounding the metal bushing (12) at least in the region of the cross-sectional narrowing (15) to compensate for the cross-sectional narrowing (15) for providing a substantially constant outer diameter of the gasket (1) and for reducing the thermal conductivity of a thermal conduction path between the housing (4) and the energy storage module (3) formed by the gasket (1).

Description

Technical Field

[0001] This invention relates to a gasket for use in a mechanical connection between an energy storage module and a housing of an electric energy storage device for a motor vehicle. The gasket has an axial hole for receiving a connecting device of the mechanical connection and axially opposite contact surfaces for pressing against the metal contact surfaces of the energy storage module and the housing. The invention also relates to an electric energy storage device, an arrangement system including an electric energy storage device and a heat source, and a motor vehicle having such an arrangement system. Background Technology

[0002] This article focuses on electric energy storage devices (EADs) for use in electrified motor vehicles, particularly hybrid vehicles. Hybrid vehicles typically have an electric motor powered by the EAD and an internal combustion engine. The EAD has a housing in which at least one EAD module is housed and held. For this purpose, a modular frame of the EAD module can be mechanically connected to the housing, for example, by screws. This mechanical connection can have a metal washer with axially opposed surfaces for pressing against the modular frame and the housing. This washer is designed to absorb the operating load of the mechanical connection, particularly the pressure and friction caused by the screws. The metal washer exhibits good mounting characteristics, high permissible surface pressure, and high stability. Furthermore, this metal washer allows for the generation of current flow for potential equalization between the EAD module and the housing.

[0003] However, metal gaskets also have good thermal conductivity. This can be detrimental when a heat source, such as the exhaust system of a hybrid vehicle, is located near the housing. The heat input from the exhaust system creates a temperature gradient within the energy storage module, which can adversely affect the operation and lifespan of the individual energy storage cells. To prevent this, the gasket can be made of insulating materials, such as ceramics, which have poorer mounting characteristics, lower permissible surface pressure, and lower stability compared to metal gaskets. Furthermore, such insulating materials are also electrically insulating, thus failing to provide potential equalization. Summary of the Invention

[0004] The objective of this invention is to provide an improved gasket for an electric energy storage device in a motor vehicle, relative to the prior art.

[0005] According to the present invention, this task is accomplished by a gasket, an electrical energy storage device, an arrangement system, and a motor vehicle. Advantageous embodiments of the present invention are the technical solutions described in the specification and accompanying drawings.

[0006] The gasket according to the invention is used in a mechanical connection between an energy storage module and a housing of an electric energy storage device for a motor vehicle. The gasket has an axial bore for receiving a connecting device of the mechanical connection and axially opposite contact surfaces for pressing against the metal contact surfaces of the energy storage module and the housing. Furthermore, the gasket includes a metal bushing for providing a current path between the contact surfaces, the current path serving to equalize the potential between the energy storage module and the housing. The axially opposite end faces of the metal bushing form the contact surfaces. Additionally, the metal bushing has a cross-sectional taper between each of the end faces to form a fuse for interrupting the current path in the event of an overcurrent. Furthermore, the gasket includes a thermally insulating material that compensates for the cross-sectional taper, at least in the region of the cross-sectional taper, surrounding the metal bushing to provide a substantially constant outer diameter of the gasket and to reduce the thermal conductivity of the thermally conductive path formed by the gasket between the housing and the energy storage module.

[0007] The invention also includes an electric energy storage device for a motor vehicle, the electric energy storage device comprising at least one energy storage module, a housing for receiving the at least one energy storage module, at least one connecting device for providing a mechanical connection between the metal contact surfaces of the at least one energy storage module and the housing, and at least one gasket according to the invention. The invention also relates to an arrangement system for a motor vehicle, particularly a hybrid vehicle, having at least one electric energy storage device and a heat source. In its installed state in the motor vehicle, the electric energy storage device can be located near the heat source, particularly near the exhaust system of an internal combustion engine and an electric motor vehicle. For this purpose, the housing can, for example, have a double-shell lower component and a housing cover, thereby forming two interconnected housing regions. At least one energy storage module can be disposed in each housing region. A channel extending in the longitudinal direction of the vehicle can be formed between the housing regions, particularly between the two shells and the housing cover of the lower component, through which an exhaust system pipe passes. Exhaust flowing in this pipe causes undesirable heat input into the electric energy storage device.

[0008] The at least one energy storage module may have multiple energy storage cells, such as prismatic battery cells, which may be held by a cell module frame. The energy storage module is mechanically connected to the at least partially metal housing via the cell module frame. For this purpose, the cell module frame and the housing have contact areas with smooth, planar contact surfaces, and the abutment surface of a washer can abut and press against said contact area. Thus, the washer is positioned between the contact surface of the energy storage module and the contact surface of the housing and is clamped or pressed by a connecting device. The connecting device is, in particular, a screw, so the mechanical connection is a threaded connection. To retain the screw, the contact area of ​​the energy storage module and the washer have through holes or bores through which the shank of the screw passes. The screw head abuts against the side of the contact area of ​​the energy storage module opposite to the contact surface. The contact area of ​​the housing may have a threaded hole for tightening the screw. Alternatively, the contact area of ​​the housing may also have a through hole, thereby securing the screw to the side of the contact area of ​​the housing opposite to the contact surface by means of a nut.

[0009] According to the present invention, the gasket now fulfills multiple functions. The gasket provides a robust mechanical connection between the housing and the energy storage module, exhibiting high permissible surface pressure and good mounting characteristics. Furthermore, the gasket reduces heat input to the energy storage module. Additionally, the gasket provides a conductive connection between the energy storage module and the housing for potential equalization. Moreover, the gasket serves as an overcurrent protection device to prevent overcurrent flow between the energy storage module and the housing. Such overcurrent can be, for example, a short-circuit current propagating through the energy storage module, which may be based, for example, on thermal runaway of the energy storage unit. Therefore, the gasket is constructed as a thermal insulation ring with integrated short-circuit protection.

[0010] To fulfill these functions, the hollow cylindrical gasket, in particular, is formed from two regions of different materials. A metal bushing forms the first region, having a hole for receiving connecting devices, and the metal end face of this bushing forms the contact surface of the gasket. Thus, the metal portion of the gasket is configured to provide a smooth, planar support on the contact surface with the clamping mating parts, i.e., the housing and the monolithic module frame. Because these contact surfaces are metallic, they are particularly robust and reliably absorb the operating load of the clamping mating parts. The metal bushing extends along the entire thickness, or axial height, of the gasket, thereby creating a current path between the monolithic module frame and the housing for potential equalization.

[0011] To form an overcurrent protection device in the form of a fuse, the bushing has a tapered cross-section, or a reduced cross-section, that is fusible in the event of an overcurrent. For this purpose, the cross-section of the bushing in the region of the tapered cross-section is smaller than the cross-section in the end face region. In other words, the cross-section is reduced between the two contact surfaces until only a residual cross-section remains, designed based on the overcurrent or short-circuit current. The design of the residual cross-section can be specifically adapted to the energy storage device and the short-circuit current that occurs there, so that the residual cross-section melts when the short-circuit current flows and interrupts the short-circuit current path from the energy storage module to the housing. The tapered cross-section thus forms a predetermined fracture portion in the event of an overcurrent, which electrically separates the two contact surfaces and therefore the metal contact surfaces in the event of a fault.

[0012] To stabilize the gasket in the region of the tapering cross-section, the gasket has an insulating material, such as a glass fiber reinforced thermosetting plastic, forming a second region of the gasket. This insulating material fills at least in the remaining cross-section of the tapering region of the metal bushing such that the cross-section of the gasket in the tapering region corresponds to its cross-section in the end face region, thus forming a hollow cylindrical shape. Therefore, the outer diameter is substantially constant in the axial height of the gasket. This insulating outer casing allows the gasket to maintain its mechanical operating load even when the fuse is triggered, i.e., when the tapering cross-section melts. Furthermore, the insulating material reduces the thermal conductivity of the gasket and thus reduces heat input from heat sources located outside the housing to the energy storage module.

[0013] This can be specified as follows: the metal bushing has two plate-shaped end members, the surfaces of which form metal end faces, and the end members are connected by a tapering section. Insulating material is disposed between the plate-shaped end members and surrounds the tapering section. Therefore, the bushing is constructed as a perforated metal core, with its opposite end members constructed as plates. A tapering section is provided between the end members, which is, for example, constructed as a tab with a constant thickness. However, the tapering section is preferably constructed as a biconical shape. Thus, the bushing is constructed as essentially hourglass-shaped.

[0014] The present invention also relates to a motor vehicle having an arrangement system according to the invention. The motor vehicle is particularly configured as a hybrid vehicle and includes an electric motor, an internal combustion engine, an exhaust system serving as a heat source, and an electric energy storage device according to the invention.

[0015] The embodiments and advantages proposed regarding the gaskets according to the invention are correspondingly applicable to the electric energy storage devices according to the invention, the arrangement systems according to the invention, and the motor vehicles according to the invention.

[0016] Other features of the invention are derived from the accompanying drawings and description. The features and combinations thereof mentioned above in the specification, as well as the features and combinations thereof mentioned below in the description and / or shown separately in the drawings, may be used not only in the combinations given separately, but also in other combinations or individually. Attached Figure Description

[0017] The present invention will now be described in detail with reference to preferred embodiments and the accompanying drawings. The drawings are as follows:

[0018] Figure 1 A perspective view of a gasket used for an electrical energy storage device is shown.

[0019] Figure 2 Showing according to Figure 1 A cross-sectional perspective view of the washer;

[0020] Figure 3 A schematic cross-sectional view of a portion of an electrical energy storage device with washers is shown; and

[0021] Figure 4 The following is a diagram showing the basis for having a gasket after overcurrent flow. Figure 3 Electrical energy storage device. Detailed Implementation

[0022] In the accompanying drawings, identical and functionally identical elements are given the same reference numerals.

[0023] Figure 1 and Figure 2 Showing the use of in Figure 3 and Figure 4 The image shows a washer 1 of an energy storage device 2. The energy storage device 2 can be used in motor vehicles, particularly hybrid vehicles. The energy storage device 2 has an energy storage module 3 and a housing 4. The energy storage module 3 has multiple stacked energy storage units 5, which are held by a unit module frame 6. The energy storage module 3, disposed within the housing 4, is fixed to the housing 4. For this purpose, the energy storage module 3 has a first contact surface 7 and the housing 4 has a second contact surface 8. The contact surfaces 7 and 8 are constructed of metal. The washer 1 is disposed between the contact surfaces 7 and 8 such that the contact surfaces 9a and 9b of the washer 1 abut against the contact surfaces 7 and 8. The unit module frame 6 and the housing 4 are connected by a screw-type connecting device 10, forming a threaded mechanical connection 11, the screw being guided through the contact surfaces 7 and 8 and the washer 1. The washer 1 is clamped between the contact surfaces 7 and 8 by the screw 10.

[0024] The washer 1 has a metal bushing 12, whose axially opposite metal end faces 13a and 13b form abutment surfaces 9a and 9b. The opposite end faces 13a and 13b are the surfaces of the plate-shaped end members 14a and 14b of the metal bushing 12. The metal bushing 12 also has a tapered section 15 connecting the end members 14a and 14b. A current path 16 can be formed between the monolithic module frame 6 and the housing 4 through the plate-shaped end members 14a and 14b and the tapered section 15 (which is configured as a double cone), enabling potential equalization between the energy storage module 3 and the housing 4. The bushing 12 also has an axial hole 17 for receiving the rod of the screw 10. The tapered section 15 forms a fuse 18, which melts when an overcurrent flows through the washer 1, thus interrupting the current path 16. Figure 4 The image shows washer 1 after fuse 18 is triggered. There, surfaces 9a and 9b are electrically disconnected, and thus the energy storage module 3 is electrically disconnected from the housing 4.

[0025] To prevent the mechanical properties of gasket 1 from deteriorating due to the tapered cross-section 15, a pressure-resistant insulating material 19, such as a thermosetting plastic, is used to supplement the cross-section of gasket 1. Therefore, even after the fuse 18 is triggered, the connection force of the threaded connection 11 can be absorbed. Furthermore, the insulating material reduces the thermal conductivity of gasket 1, thereby reducing the heat input from heat sources outside the housing 4 to the energy storage module 3 via gasket 1.

Claims

1. A washer (1) for use in a mechanical connection (11) between an energy storage module (3) and a housing (4) of an electric energy storage device (2) for a motor vehicle, the washer (1) having an axial hole (17) for receiving a connecting device (10) of the mechanical connection (11) and axially opposite contact surfaces (9a, 9b) for pressing against the metal contact surfaces (7, 8) of the energy storage module (4) and the housing (4), characterized in that - A metal bushing (12) for providing a current path (16) between the contact surfaces (7, 8) for potential equalization between the energy storage module (3) and the housing (4), the metal bushing having axially opposite end faces (13a, 13b) forming abutment surfaces (9a, 9b) and having a tapered section (15) between the end faces (13a, 13b) forming a fuse (18) for interrupting the current path (16) in the event of an overcurrent. - Thermal insulation material (19) that compensates for the narrowing of the cross section (15) surrounds the metal bushing (12) at least in the region of the tapered cross section (15) to provide a substantially constant outer diameter of the gasket (1) and to reduce the thermal conductivity of the thermal path formed through the gasket (1) between the housing (4) and the energy storage module (3).

2. The washer (1) according to claim 1, characterized in that, The insulation material (19) is a thermosetting plastic.

3. The washer (1) according to claim 1, characterized in that, The insulation material (19) is a glass fiber reinforced thermosetting plastic.

4. The washer (1) according to claim 1, characterized in that, The washer (1) is constructed as a hollow cylinder.

5. The washer (1) according to any one of claims 1 to 4, characterized in that, The metal bushing (12) has two plate-shaped end members (14a, 14b), the surfaces of each end member forming metal end faces (13a, 13b), and the end members are connected by a cross-sectional tapering portion (15). Thermal insulation material (19) is disposed between the plate-shaped end members (14a, 14b) and surrounds the cross-sectional tapering portion (15).

6. The washer (1) according to any one of claims 1 to 4, characterized in that, The metal bushing (12) is configured as biconical at least in the region of the tapering section (15).

7. An electric energy storage device (2) for a motor vehicle, the electric energy storage device comprising: - At least one energy storage module (3). - A housing (4) for accommodating the at least one energy storage module (3). - At least one connecting device (10) for providing a mechanical connection (11) between the metal contact surfaces (7, 8) of the at least one energy storage module (3) and the housing (4), and - At least one washer (1) according to any one of claims 1 to 6, wherein the contact surface (9a, 9b) of the washer is abutted against the contact surface (7, 8).

8. The energy storage device (2) according to claim 7, characterized in that, The metal contact surface (7) of the energy storage module (3) is formed on the single module frame (6) of the energy storage unit (5) for holding the energy storage module (3).

9. An arrangement system for a motor vehicle, the arrangement system having an electrical energy storage device (2) according to claim 8 and a heat source designed to input heat into the housing (4).

10. The arrangement system according to claim 9, characterized in that, The heat source is a pipe of the exhaust system of a motor vehicle, and the housing (4) has at least two adjacent housing regions, with the pipe extending between each of the housing regions.

11. A motor vehicle having the arrangement system according to claim 9 or 10.

12. The motor vehicle according to claim 11, characterized in that, The motor vehicle in question is a hybrid vehicle.

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