Patent Application
20240234982
The present invention relates to electromechanical connections and more particularly to electromechanical connections with passive fuses.
Module connectors and busbars are generally known from the state of the art. Module connectors are used, for example, to connect battery modules to each other. The interconnected battery modules form a battery or an energy storage device. The battery modules, also known as cell modules, each comprise twelve 60 Ah cells, for example. The battery modules are arranged in a housing tray of an electric vehicle, for example. The battery modules serve as energy storage for the electric vehicle. The busbars in turn connect the interconnected battery modules to the battery management system, the charging interface or the interface to the drive unit.
High safety requirements are placed on energy storage devices in electric vehicles. In the event of unintended reactions within the energy storage device, special safety measures are required to reduce the risk to occupants.
In this context, it has now become apparent that there is a need to further improve such a module connector, in particular there is a further need to provide a cost-effective and safe module connector. It is therefore a task of the present invention to provide an improved module connector, in particular it is a task of the present invention to provide a module connector that is as cost-effective and safe as possible.
These and other tasks, which are still mentioned when reading the following description or can be recognized by the skilled person, are solved by the subject matter of the independent claims. The dependent claims further shape the central idea of the present invention in a particularly advantageous manner.
A device according to the invention for electrically and mechanically connecting battery modules in an energy storage device or two busbars between an energy storage device and a further system, comprising a first connection element with a first interface, wherein the first interface is configured to be electrically and mechanically connected to a first battery module in an energy storage device or a first busbar connected to an energy storage device; a second connection element with a second interface, wherein the second interface is configured to be electrically and mechanically connected to a second battery module in the energy storage device or a second busbar connected to a further system; a connection module, wherein the connection module is configured to provide an electrical and mechanical connection between a first connection region of the first connection element and a second connection region of the second connection element; wherein the connection module is further configured to passively open the electrical and mechanical connection between the first connection region of the first connection element and the second connection region of the second connection element when a triggering temperature is reached.
The electrical connection, in the present case, means a conductive connection of a pole (for example a positive pole) of a first battery module with a pole (for example a corresponding negative pole) of a second battery module for the transmission of current. The electrical connection can be used to connect or interconnect several battery modules and thus increase the capacity of an energy storage device comprising the respective battery modules. Furthermore, the electrical connection in this case means the conductive connection of a first busbar (or power rail), which is connected to an energy storage device of an electric vehicle, to a second busbar (or power rail), which is connected to a further system. The further system is, for example, a battery management system, a charging interface, an interface to the drive unit in the electric vehicle or another energy storage device. The mechanical connection, in the present case, means that the electrical connection is realized via one or more mechanical elements, for example busbars. The mechanical connection is also used to transfer heat via heat conduction between battery modules and/or the energy storage device and other/further systems. Opening the mechanical connection interrupts the heat transfer via heat conduction. Opening the mechanical connection interrupts the electrical connection. The term busbar refers to a conductor for electrical current made of a rigid material, such as copper. The busbar can be in one or more parts. It should be noted that the first busbar and second busbar can also be a first part and a second part of a single busbar. In addition to electricity, the busbar can also transmit heat. In the present case, the term battery module refers to an energy storage device that is designed to be connected to a further energy storage device. Preferably, the term battery module refers to an energy storage device that comprises several pouch cells. The term connection element is to be understood broadly here and includes all mechanical elements that are set up to connect two elements to each other. The connection element can have different geometries. For example, the connection element can have a rod-shaped geometry, an arc-shaped geometry, a triangular geometry or a trapezoidal geometry. The connection element can, for example, have a cylindrical, square, rectangular, polygonal or oval cross-section. The connection element can have a constant or variable cross-section (or material thickness) over the length of the connection element. The connection element serves as a means of transferring electricity and heat, with the heat being dissipated from the battery modules. The connection element can be made of any conductive material. For example, the connection element is made of copper, aluminum with a tin coating or aluminum with a nickel coating. The term interface is to be understood broadly here and means a mechanical interface, for example a through-hole rung, a slotted hole, each of which can be connected to a pole of a battery module with a corresponding screw. For example, the mechanical interface can also be designed as a contact surface for a clamping device that connects the connection element to the terminal with a force fit. The term connection region is to be understood broadly in the present case and includes a mechanical area of the connection element. For example, the connection region is arranged opposite the interface. For example, the connection region is designed as a flat area that is accessible through and is set up to form a force-fit/friction-locked connection (e.g. clamping) with a corresponding counterpart. For example, the connection region has the same cross-section as the remaining region of the connection element excluding the interface. For example, the connection region has a rectangular cross-section and a rectangular and flat connecting surface. In other words, the connection region can be a partial region of the busbar, which region is used for clamping. The term connection module is to be understood broadly here and means a mechanical component that is designed to establish an electrical and mechanical connection between two connection regions and to passively open and/or release the electrical and mechanical connection when a triggering temperature is reached. The connection regions are preferably arranged spatially separated from each other. In the present case, the term passive opening means that no external energy has to be added for opening and there is no active activation. Furthermore, passive means that the opening is automatic and independent. The term trigger temperature means a predetermined temperature, for example 140° C. or 170° C., at which a fault in the battery module can be inferred. When the trigger temperature is reached, the connection module opens the connection between the first connection region of the first connection element and the second connection region of the second connection element. For example, the connection module is designed as a mechanical device with a temperature-dependent safety mechanism. The mechanical device comprises, for example, a spring mechanism, a cable pull system, a clamping mechanism or a gear mechanism for providing the electrical and mechanical connection and for opening it. The passive opening takes place, for example, via temperature-sensitive materials, whereby the materials can be solid or liquid. The temperature-sensitive materials can have positive or negative coefficients of thermal expansion.
The invention is based on the insight that in the event of short circuits, intended thermal reactions and/or unwanted chemical reactions within a battery module, there is a great risk that the event will spread to the neighboring battery modules. The high temperatures and/or excessively high currents are passed on to neighboring connected battery modules via the connection elements. This can lead to a thermal chain reaction, which can ultimately result in a fire and/or an explosion of the energy storage device. Due to the high risk to life and limb of the occupants of a vehicle, it is necessary to delay this thermal chain reaction or the fire and/or explosion for as long as possible when an initial event occurs (i.e. failure of a first battery module) so that the occupants can get to safety. Such an initial event can be triggered, for example, by a traffic accident or by an unintended chemical reaction inside the battery cells. It is a problem that as a result of the traffic accident, not only the parts of the battery module can be damaged, but also the controls, actuators, energy and control lines, such that an active opening of the electrical and mechanical connection may no longer be possible. The present invention solves the problem by providing a connection module that is set up to passively provide an electrical and mechanical connection below a trigger temperature between a first connection region of a first connection element of a first battery module and a second connection region of a second connection element of a second battery module. This ensures operation of the battery under normal conditions. When the trigger temperature is reached, a passive safety mechanism is triggered, which opens the electrical and mechanical connection between the first connection region of the first connection element of the first battery module and the second connection region of the second connection element of the second battery module in such a way that thermal propagation (i.e. thermal runaway) of the entire energy storage device of the vehicle is delayed. This can advantageously give the occupants of the vehicle time to move away from the vehicle. In other words, the invention is a thermal fuse for high-voltage systems.
Preferably, the connection module comprises a passive safety element that is set up to trigger at the temperature limit such that the electrical and mechanical connection between the first connection region of the first connection element and the second connection region of the second connection element is opened. The term passive safety element is to be understood broadly at and means a safety element that is set up to trigger a safety mechanism without external energy supply or control. The passive safety element comprises, for example, a temperature-sensitive material. The temperature-sensitive material changes its volume when the temperature changes, for example. For example, the temperature-sensitive material has a positive coefficient of thermal expansion and is a liquid that is arranged in a glass container, such as an ampoule. When the triggering temperature is reached, the glass container bursts, which passively triggers the safety mechanism. For example, the temperature-sensitive material has a negative coefficient of thermal expansion and is a solid. When the triggering temperature is reached, for example, a clamp is released, which passively triggers the locking mechanism. Advantageously, this makes it possible to reliably ensure the opening of the connection between the first connection element and the second connection element independently of higher-level control systems and/or energy systems.
Preferably, the passive safety element comprises a container with a liquid which is designed to burst when the triggering temperature is reached. Preferably the container is a bursting vessel with liquid according to EP 2630994, EP 3360605, U.S. Pat. Nos. 9,579,531, 9,821,181, 9,889,324 and/or KR 20130097674. The liquid may be, for example, halon, fluorinated ketone or a perfluorinated ethyl isopropyl ketone. The liquid can be selected so that at a certain limit temperature it expands in such a way that the bursting vessel bursts or breaks. The liquid can advantageously undergo a phase transition and become gaseous, which significantly increases the volume and thus the speed of expansion. This can advantageously ensure that the liquid is distributed around the first and second connection regions.
Preferably, the connection module comprises a third connection element that is set up to be electrically and mechanically connected to the first connection region of the first connection element and to the second connection region of the second connection element. The third connection element is made of copper, for example. The third connection element has, for example, a round, oval, square, rectangular or polygonal cross-section. Preferably, the third connection element has a rectangular cross-section. Preferably, the third connection element has a similar cross-section to the first and second connection elements. Preferably, the third connection element is friction-locked to the first connection element and the second connection element. The third connection element can advantageously be used to provide high currents between the first battery module and the two battery modules. The third connection element is pressed against the first connection element and the connection element via the safety element, for example, in such a way that an electrical and mechanical connection is provided. In other words, the high current is not conducted via the safety element, but via the third connection element.
Preferably, the connection module comprises a spring mechanism that is configured to provide the electrical and mechanical connection between the first connection region of the first connection element and the second connection region of the second connection element. The spring mechanism ensures simplified assembly and secure assembly of the three connection elements and the locking element. Advantageously, the safety element can be reliably brought into force-fit engagement with the third connection element via the spring mechanism without damaging it by, for example, an interference fit. Furthermore, the spring mechanism can advantageously compensate manufacturing and/or assembly tolerances. Furthermore, the spring mechanism can advantageously be passively released or opened again when pre-tensioned via the locking element.
Preferably, the spring mechanism is pretensioned via the container in such a way that the third connection element is pressed against the first connection region of the first connection element and the second connection region of the second connection element. This reliably enables an electrical and mechanical connection between the first battery module and the second battery module, which is opened again when the triggering temperature is reached by bursting the safety element or the holder.
Preferably, the connection module comprises a housing with at least one opening, wherein the housing closes the at least one opening when the triggering temperature is reached in such a way that at least the first connection region of the first connection element and the second connection region of the second connection element and a released liquid are enclosed with regard to the environment so that the liquid cannot escape from the housing and can cover the first connection region of the first connection element and the second connection region of the second connection element to extinguish an electric arc. Hot gases or a hot air flow can reach the vicinity of the connection module through the at least one opening in the housing. The hot gases or the hot air flow are caused by the temperature rise of the battery modules as a result of a malfunction. The opening can have a positive effect on the reaction time of the connection module, as the housing does not have to be completely heated until the trigger temperature is reached. This means that the electrical and mechanical connection can be opened passively more quickly. When the connection between two battery modules connected to each other is opened, a direct-current conductor causes an electric arc, which prevents the electrical connection from opening and can therefore initiate or intensify the thermal runaway. The released liquid can then advantageously counteract the resulting electric arc and thus separate or open the electrical and thermal connection in order to prevent or delay the thermal runaway. The housing can, for example, be designed in such a way that it passively closes the opening again when the triggering temperature is reached. This can be realized, for example, via a slider construction, which is also triggered via the passive safety element. The housing can be designed in one or more parts. In the case of a multi-part design, the housing can, for example, be mounted using plug-in connections, screw connections, adhesive connections and/or welded connections.
Preferably, the liquid is an extinguishing liquid. Advantageously, this can better counteract the electric arc.
Preferably, the container is arranged essentially at the level of the first connection region of the first connection element and the second connection region of the second connection element or above it. An arrangement at the level of or above the first connection element and the second connection element advantageously allows the liquid to reach the electric arc directly in order to extinguish it efficiently. The container is therefore not arranged below the third connection element in the obvious way, but above it in the opposite way. This is made possible, for example, via a slider construction, whereby the container is not brought into direct engagement with the third connection element, but indirectly via a slider that is firmly connected to the third connection element.
Preferably, the housing is made of a high-temperature-resistant plastic. This can advantageously ensure the safe and correct functioning of the device for the electrical and mechanical connection of battery modules even in the event of an extreme rise in temperature.
A further aspect relates to a system comprising: at least one device described in more detail above; at least one first battery module and a second battery module; and/or at least one energy storage device and a further system; at least a first and a second busbar between the energy storage device and the further system.
Preferably, the further system is a battery management system, a charging interface, an interface of a drive unit or an additional energy storage device.
A further aspect relates to a vehicle comprising a system described in more detail above.
A further aspect relates to the use of a container with extinguishing liquid contained therein in a device described in more detail above.
A further aspect relates to the use of a connection module with a passive fuse for interrupting the electrical and mechanical connection in a device described in more detail above.
A detailed description of the figures is given below.
The term non-transitory computer-readable medium does not encompass transitory electrical or electromagnetic signals propagating through a medium (such as on a carrier wave). Non-limiting examples of a non-transitory computer-readable medium are nonvolatile memory circuits (such as a flash memory circuit, an erasable programmable read-only memory circuit, or a mask read-only memory circuit), volatile memory circuits (such as a static random access memory circuit or a dynamic random access memory circuit), magnetic storage media (such as an analog or digital magnetic tape or a hard disk drive), and optical storage media (such as a CD, a DVD, or a Blu-ray Disc).
The term “set” generally means a grouping of one or more elements. The elements of a set do not necessarily need to have any characteristics in common or otherwise belong together. The phrase “at least one of A, B, and C” should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.” The phrase “at least one of A, B, or C” should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR.
| Number | Date | Country | Kind |
|---|---|---|---|
| 21183547 | Jul 2021 | EP | regional |
This application is a continuation of International Application No. PCT/EP2022/068327 filed Jul. 1, 2022, which claims the benefit of EP Application No. 21183547 filed Jul. 2, 2021. The entire disclosures of the above applications are incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 20240136677 A1 | Apr 2024 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/EP22/68327 | Jul 2022 | WO |
| Child | 18401550 | US |
