BATTERY MODULE WITH A FUSE MIXED FUSE

Description

[0001] The present invention relates to a battery module comprising a housing, at least one terminal, and a plurality of electrochemical energy storage cells within the housing. Furthermore, the battery module has at least one fuse. FIELD OF APPLICATION AND STATE OF THE ART

[0002] Battery modules are rechargeable electrical energy storage devices used in stationary energy storage systems, for example, but also in many other areas. A battery module combines a large number of individual electrochemical energy storage cells to provide the high energy densities required for various applications. Several battery modules can, in turn, be combined to form a larger battery storage system.

[0003] Each electrochemical energy storage cell of the battery module comprises at least one positive and at least one negative electrode, which are separated from each other by a separator. In general, an electrochemical, energy-producing reaction takes place in electrochemical cells. This reaction consists of two electrically coupled but spatially separated partial reactions. One partial reaction, which takes place at a comparatively lower redox potential, takes place at the negative electrode, and one at a comparatively higher redox potential at the positive electrode. During discharge, electrons are released at the negative electrode through an oxidation process, resulting in an electron flow via an external consumer to the positive electrode, from which a corresponding amount of electrons is absorbed. A reduction process therefore takes place at the positive electrode.At the same time, an ion current corresponding to the electrode reaction occurs within the electrochemical cell for the purpose of charge equalization. This ion current flows through the separator and is maintained by an ion-conducting electrolyte.

[0004] In secondary (rechargeable) electrochemical cells, this discharge reaction is reversible, meaning that it is possible to reverse the conversion of chemical energy into electrical energy that occurs during discharge.

[0005] An electrochemical energy storage cell often used in battery modules is the lithium-ion cell. This cell comprises electrodes that can reversibly absorb and release lithium ions, as well as an electrolyte containing lithium ions.

[0006] Electrochemical cells, and especially lithium-ion cells, come in various designs. In addition to prismatic shapes, button cells and cylindrical round cells are widely used. Both button cells and cylindrical round cells have a circular base. Cylindrical round cells differ from button cells in that button cells have a height that is less than their diameter. Cylindrical round cells, on the other hand, have a height that is greater than their diameter. In addition to prismatic energy storage cells, these cylindrical round cells are primarily used for the construction of battery modules.

[0007] DE 102010055918 A1 discloses a fuse device for a high-voltage cable in a motor vehicle. The fuse device comprises a fusible element in the form of a stranded wire made of a plurality of individual wires. The high-voltage cable connects the high-voltage battery to the electric drive motor of the motor vehicle. The fuse device, including the fusible element, is arranged between the high-voltage battery and the drive motor.

[0008] DE 102017004915 A1 discloses an overcurrent protection device with a stranded wire made of individual wires, which can be designed as a fuse. Within a battery module, the individual energy storage cells can be secured using cell holders. Several energy storage cells can be combined and interconnected in the form of battery blocks. For example, two or more such battery blocks can be combined in a battery module within a housing, thus forming a single unit. The battery modules can then, in turn, form the building blocks of a battery system.

[0009] Heat is generated during the operation of electrochemical cells, and especially during the operation of a battery module. The cells heat up both during energy release and during charging. Overheating can lead to impairments and damage to the electrochemical cells. Furthermore, an overheated battery module, and especially a short circuit, can pose a significant fire hazard. Therefore, a battery module is usually equipped with a fuse, usually a melting fuse, which ensures that the battery module is shut down in the event of an emergency. Once the fuse is triggered, the battery module is generally defective and can no longer be used.

[0010] Such fuses are primarily used to protect against overcurrents, which can occur particularly in the event of short circuits in battery modules with higher power and / or capacity. Conventionally used fuses are open blade fuses, which essentially consist of a stamped part, e.g., made of copper sheet. Such fuses are relatively inexpensive. However, they are mechanically sensitive and have only limited breaking capacity. Furthermore, when they are cut or melted, glowing metal droplets can form, which can pose a fire hazard.

[0011] As a further development of these open blade fuses, housed blade fuses are used. Although these housed blade fuses are mechanically less sensitive and typically do not release glowing particles when melted, they still have only limited breaking capacity and are relatively expensive.

[0012] So-called ceramic tube fuses, which are mechanically robust and have a high breaking capacity, are widely used. These ceramic tube fuses are filled with quartz sand, for example. The melt products generated during the breaking process, especially glowing metal drops, cannot escape, are quickly extinguished, and remain safely contained within the ceramic tube. However, such ceramic tube fuses are relatively expensive.

[0013] All of these known fuses are mechanically rigid, which can pose problems from a design perspective. Especially with the mechanically very sensitive blade fuses, no bending moments must be exerted on the rigid fuse element when screwing it on, as otherwise the fuse element could be damaged and possibly no longer meet its specifications.

[0014] Furthermore, especially in large-volume battery modules, thermal expansion and temperature changes, and the associated volume changes, can exert mechanical stress on the installed fuse, which can also lead to functional impairments of the fuse. In addition, there are other possible mechanical stresses on the installed fuse within the battery module, for example, during transport or installation of a battery module. When handling battery modules, which can weigh approximately 40 kg, vibrations or similar movements can occur. All of these mechanical influences can negatively impact the integrity of the fuse.

[0015] A damaged fuse may, under certain circumstances, trigger at currents below the fuse's rated current. This would lead to premature shutdown and failure of the battery module.

[0016] Furthermore, problems can arise due to mechanical tolerances during battery module manufacturing. Such tolerances make the installation of a conventional rigid fuse difficult. TASK AND SOLUTION

[0017] Against this background, the invention seeks to provide an improved fuse that is particularly suitable for use as a short-circuit protection device in battery modules. The aim is to propose a battery module equipped with a fuse that can be installed in the battery module in a structurally practical manner and that is also mechanically robust, so that there is no risk of damage or impairment to the fuse during normal operation of the battery module, and in particular during transport and assembly of the battery module.

[0018] This object is achieved by a battery module as is the subject matter of claim 1. Preferred embodiments of the battery module and in particular of the fuse of the battery module emerge from the dependent claims.

[0019] The battery module according to the invention comprises a housing and at least one connection element, in particular a connector plug, for connecting the battery module. A plurality of electrochemical energy storage cells are provided within the housing. The battery module according to the invention further comprises at least one fuse, which serves in particular to protect the battery module against short circuits. The fuse comprises at least one fusible conductor.

[0020] The core of the invention is that the fuse comprises a stranded wire. Stranded wires are known to be constructed from a plurality of individual wires. This measure gives the fuse a mechanical flexibility that distinguishes it from conventional fuses. The mechanical flexibility of the fuse offers various advantages, particularly from a design perspective. Above all, such a flexible fuse can compensate for mechanical tolerances within the battery module during assembly. Furthermore, the flexible fuse can yield without being damaged in the event of length or volume changes within the battery module, which may be caused thermally and / or mechanically.

[0021] The flexibility of the fuse is combined with its bendability and a certain elasticity, so that the material of the fuse is not compromised when bending moments occur. Above all, the wire strand of the fuse allows the fuse to be bent in more than two directions—not just up and down, for example, but also to the right and left. The flexibility of the fuse is preferably designed such that a deviation from the original orientation of the wire strand in more than two directions by a bending angle of up to at least 45°, preferably by a bending angle of up to at least 90°, is possible without causing damage to the fuse or impairing its function.

[0022] Overall, the mechanical flexibility of the fuse allows for the compensation and bridging of mechanical stresses and tolerances within the battery module. Furthermore, thermal stresses can be compensated for, as the fuse is flexible and compliant.

[0023] Depending on the various design options for the fuse of the battery module according to the invention, the fuse element of the fuse can be formed by the stranded wire, or another element of the fuse can be formed by the stranded wire. Further details on these various embodiments can be found in the following description.

[0024] The fuse of the battery module is expediently adapted to the respective requirements of the battery module's design. In particular, the fuse is adapted to the respective current conditions and the desired or required cut-off voltages. In this regard, the fuse in preferred embodiments of the battery module is characterized by the following additional feature: a. The fuse is designed for a nominal current (rated current) in a range between 10 and 1000 amperes, preferably between 200 and 500 amperes.

[0025] Such a fuse is particularly suitable for high-current protection in conventional battery modules, where currents in the range of 500 to 5,000 amperes are to be expected in the event of a short circuit. With a rated current in the range between 10 and 1,000 amperes, and especially between 200 and 500 amperes, the fuse reliably blows in the event of a short circuit, immediately shutting down the battery module.

[0026] According to the invention, the battery module has the following feature: a. The fuse includes two terminals for connection to mounting points in the battery module.

[0027] In preferred embodiments, the two connections are cable lugs and / or connectors and / or wire end ferrules.

[0028] Such connections are ideal for quick and easy installation. However, the fuse can also be connected by welding or soldering, for example.

[0029] Various points within the battery module can be considered as mounting points. Power rails or circuit boards, for example, can also serve as mounting points. To protect the battery module against short circuits, it is particularly advantageous if the fuse protects all of the energy storage cells, so that the entire battery module is immediately shut down or all cells are disconnected in the event of an overcurrent. Particularly preferably, the fuse can be arranged, for example, between a busbar or power or connection bar that combines all of the energy storage cells and the power line that leads to a plug or the connection element of the battery module.

[0030] The fuse of the battery module according to the invention can be designed in two basic embodiments. In both cases, the wire strand of the fuse forms the flexible element of the fuse, which gives the fuse a mechanical flexibility overall, which offers many advantages, especially in connection with a fuse in battery modules.

[0031] In a first basic embodiment, the stranded wire itself forms the fuse element of the fuse. In a second basic embodiment, a stranded wire is provided as a flexible element in addition to the actual fuse element. In this second basic embodiment, the stranded wire is generally not designed as a fuse element itself; rather, it is characterized by a higher current-carrying capacity than the fuse element. In this second basic embodiment, the fuse element can also be formed from a stranded wire and thus also be mechanically flexible. However, a rigid fuse element can also be provided.

[0032] The following explanations initially refer to the first basic embodiment, in which the wire strand itself is the fusible conductor.

[0033] Preferably, in particular in this embodiment, it is provided that the wire strand is characterized by at least one of the following additional features: a. The individual wires of the stranded wire are made of a metallic material. b. The metallic material includes silver and / or tin and / or copper.

[0034] For example, in this embodiment, the wire strand can be made from a plurality of thin, conventional fusible conductor wires. The individual wires can be processed, for example, into a braided flat conductor or a twisted strand with a round cross-section.

[0035] Silver is particularly suitable for use in such fuse wires. Combinations with tin, for example, in the form of tin coatings on silver wires, are particularly advantageous in terms of their melting properties. Alternatively, silver-plated copper, for example, can be used as a material for the fuse.

[0036] By selecting the dimensions and material for the wire strand, the fuse can be adapted to various requirements and conditions. For example, the length of the wire strand can be adjusted to accommodate different interruption voltages. By adjusting the thickness of the entire wire strand, for example, by adjusting the number or diameter of the individual wires, the fuse can be adapted to the respective current conditions.

[0037] In a particularly preferred embodiment, the battery module is characterized by the following additional feature: a. The fusible element has a length of at least 2 cm.

[0038] A length of at least 2 cm is particularly suitable for battery modules in the high-current range, where the fuse should be triggered in a range of, for example, 300 amperes. The thickness or cross-sectional area of ​​the fuse element or wire strand in this design can, for example, be in a range of 0.4 to 10 mm². The fuse element can, for example, have a roughly round cross-section or a profiled cross-section.

[0039] A minimum length of 2 cm is particularly advantageous because if the fusible element burns through, i.e. if the fuse is triggered, the two remaining ends of the fusible element fall downwards due to gravity, thus enlarging the separation point between the molten fusible element ends. This is advantageous because any arc that may arise due to the burn-through is more easily extinguished. Current flows through a resulting arc and generates heat of over 2,000 °C, thus representing a significant fire hazard. Quick extinguishing of the arc is therefore advantageous and important. The longer the fusible element, the lower the risk of a persistent arc. It may therefore be further preferred for the fusible element to be 3 cm or more.

[0040] In a simple design of such a fuse, a stranded wire forming the fuse element and having a corresponding length, for example, 2 or 3 cm, is equipped with a connector on both sides for installation within the battery module. For example, a cable lug can be located at both ends of the stranded wire. In this simple design of the fuse, the fuse is formed by a stranded wire designed as a fuse element with two cable lugs or, if necessary, other connecting elements attached to it.

[0041] In a preferred development of this embodiment of the fuse, at least one of the following additional features is provided: a. The wire strand is surrounded by an electrically insulating material that is mechanically flexible; b. the electrically insulating material is formed by a ceramic material, in particular ceramic beads.

[0042] Preferably, the aforementioned features a. and b. are implemented in combination with one another.

[0043] The flexibility of the insulation material ensures the overall mechanical flexibility of the fuse.

[0044] The insulation material is made of a plurality of ceramic beads, which is a particularly simple and highly advantageous design. When the fuse is intact, the ceramic beads enclose the stranded wire that forms the fuse element. When an overcurrent triggers, the fuse element or the stranded wire burns through. The separated ends of the stranded wire fall downwards or are pulled downwards by the weight of the ceramic beads. This rapidly increases the distance between the ends of the stranded wire, so that the arc gap or arc zone quickly expands and any arc that may have occurred is extinguished.

[0045] In addition to maintaining the mechanical flexibility of the fuse, ceramic beads have the advantage over other flexible electrical insulation materials, such as glass fiber fabric, that the ceramic beads promote the extinguishing of the arc by quickly separating the melting ends from each other and do not, as would be the case with a glass fiber fabric, hinder the separation of the ends within the melting zone.

[0046] Ceramic beads suitable for this design are generally available at low cost and are made of steatite, for example. Suitable ceramic beads should have a thermal resistance of up to 1,000 °C or 1,200 °C, for example.

[0047] In a further, particularly preferred development of this first basic embodiment of the fuse, in which the wire strand forms the fusible conductor, at least one of the following additional features is provided: a. The battery module or the fuse comprises at least one means for pulling apart parts of the wire strand after they have melted; b. the at least one means for pulling apart parts of the wire strand is one or more spring elements; c. the spring elements are spiral springs.

[0048] Preferably, the aforementioned features a. and b., and in particular the aforementioned features a., b. and c., are implemented in combination with one another.

[0049] These measures further assist in pulling the melted ends of the fusible element apart, resulting in a rapid extinguishing of any arc that may occur.

[0050] In a preferred embodiment of this aspect of the invention, at least one of the following additional features is provided: a. The at least one means for pulling apart parts of the wire strand acts in the longitudinal direction of the wire strand; b. the means for pulling apart parts of the wire strand is a spiral spring which extends in the longitudinal direction of the wire strand and which is mechanically connected to the wire strand at at least one point, preferably at two or more points.

[0051] Preferably, the aforementioned features a. and b. are implemented in combination with one another.

[0052] In a particularly preferred manner, the spiral spring extends over the entire length of the stranded wire that forms the fusible link. When the fuse is installed in the battery module, the spiral spring, which is preferably connected to the stranded wire at several points, for example at two or more points, is pulled apart so that the fuse is energized when installed. When an overcurrent occurs, i.e. when the fuse is triggered, the fusible link melts first. The current then flows through the spiral spring, which is for example a steel spring, and the spiral spring also melts quickly. Both ends of the melted fusible link are pulled apart by the two remaining parts of the spiral spring and quickly moved away from each other. This also leads to very rapid extinguishing of any arc that may occur.

[0053] The mechanical connection of the spiral spring to the fusible element or the wire strand can, for example, be designed in such a way that each spring turn of the spiral spring passes through the wire strand.

[0054] In another embodiment of this aspect of the invention with means for pulling apart parts of the wire strand after it has melted through, at least one of the following additional features is provided: a. The at least one means for pulling apart parts of the wire strand acts perpendicularly with respect to the longitudinal extent of the wire strand; b. the at least one means for pulling apart parts of the wire strand is at least one spring element, preferably two spring elements; c. the at least one means for pulling apart parts of the wire strand is implemented by two spring elements that act on different sections of the wire strand.

[0055] In this design of the fuse, for example, a single spring element can engage the wire strand perpendicular to its longitudinal extension and place it under tension. This means for pulling apart can be, for example, a coil spring, a leaf spring, or a resilient housing structural component. In this design, too, the arcing zone is pulled apart or, depending on the design, pushed apart by the force of the spring element or another comparable means, resulting in rapid extinguishing of any arc that may occur.

[0056] In other embodiments, for example, two means for pulling the wire apart may be provided, for example, two coil springs or other spring elements that, when installed, exert mechanical force on the fuse element. These two means advantageously act in different directions, so that if the wire strand melts, the remaining ends of the wire strand are pulled in different directions, thus reliably extinguishing any arc that may occur very quickly.

[0057] These fuse designs with spring elements or other means for pulling apart parts of the wire strand, which act perpendicularly to the longitudinal extension of the wire strand, can particularly advantageously be additionally equipped with mechanically flexible insulating materials, such as ceramic beads. The flexible insulating materials provide electrical insulation for the fuse element. The insulating materials, especially the ceramic beads, also assist in quickly pulling apart the melted fuse element ends.

[0058] In the second basic design of the fuse mentioned above, the stranded wire does not form the fuse element, but rather an additional, flexible element of the fuse element, which is provided next to the actual fuse element. In this design, the stranded wire has a higher current-carrying capacity than the fuse element, so that the stranded wire generally does not melt under load. The fuse element itself can be rigid or flexible and, for example, also be formed from a stranded wire, but in this case, it is made of fuse elements.

[0059] In this embodiment of the fuse, at least one of the following features is provided: a. In addition to the fusible element, the fuse comprises a mechanically flexible electrical line section formed by the stranded wire; b. The mechanically flexible line section formed by the stranded wire is under prestress, in particular under spring tension, in the assembled state; c. The prestress, in particular the spring tension, acts in the longitudinal direction of the mechanically flexible electrical line section and causes a contraction of the mechanically flexible electrical line section when the fusible element melts.

[0060] In particularly preferred embodiments of this embodiment of the fuse, the aforementioned features a. and b. and, particularly preferably, the aforementioned features a. and b. and c. are implemented in combination with one another.

[0061] In the simplest case, the fuse in this design comprises a fuse element, which can be rigid or flexible, and a flexible line section formed by a stranded wire, for example, a copper wire. Both sections are connected in series, for example, by means of a butt connector or by welding, so that both line sections are electrically and mechanically connected. Together, they form the fuse element, which can be attached to the corresponding mounting points in the battery module via appropriate connections, for example, using two cable lugs. The flexible line section, i.e. the stranded wire, has a higher current-carrying capacity than the fuse element.

[0062] The fusible element can be a rigid fusible element, such as a stamped copper part. In other embodiments, the fusible element can also be a stranded wire, but then it has the corresponding melting properties.

[0063] According to the aforementioned preferred feature b, the mechanically flexible cable section is prestressed in the assembled state. For this purpose, a spring element, for example a coil spring, can span the area of ​​the mechanically flexible cable section and place it under tension.

[0064] In the event of an overcurrent that causes the fuse to blow, the fusible element melts, while the flexible section of the wire remains intact. However, the pre-tension causes the flexible section to contract, effectively spreading the arcing zone in the area of ​​the melted ends of the fusible element and extinguishing any arc that may occur.

[0065] In preferred refinements of the various fuse designs, the fuse can be coated with a drop of solder, thus serving as a full-area fuse. By adding solder, the characteristics of the fuse can be intentionally modified and / or adjusted. This adjustment can apply to the entire fuse or just a portion of it. For example, if a copper fuse element is coated with a small amount of tin, the tin initially alloys with the copper surface to form bronze. Bronze has a significantly higher resistance than copper, increasing the resistance of the fuse element. This increases the thermal output at this point, causing the fuse element to become even hotter and thus accelerating the further alloying process. This can also be referred to as deliberate "thermal runaway."The advantage of this is that there is no current range in which the fuse element remains permanently extremely hot, such as glowing. The adjustability of the characteristic in this design therefore offers particular advantages, even though the fuse in this design may age more quickly under load.

[0066] The invention further comprises a battery storage system comprising at least one battery module according to the above description with a mechanically flexible fuse. Preferably, all battery modules of the battery storage system are equipped with such a flexible fuse. For further features of the fuses of the battery modules of the battery storage system, reference is made to the above description.

[0067] Finally, the invention includes a fuse as described above. Such a fuse is particularly suitable for short-circuit protection of a battery module, but can, in principle, also be used for other applications. For further features of this fuse, reference is made to the above description.

[0068] Further features and advantages of the invention will become apparent from the following description of preferred embodiments in conjunction with the drawings. The individual features may be implemented individually or in combination with one another. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] The figures show: Fig. 1 schematic representation of a battery module according to the invention with a fuse; Fig. 2 representation of a fuse in a first embodiment with illustration of the stages when the fuse is triggered (partial figures A to C); Fig. 3 representation of a fuse in a further embodiment with illustration of the stages when the fuse is triggered (partial figures A to D); Fig. 4 representation of a fuse in a further embodiment with illustration of the stages when the fuse is triggered (partial figures A to D); Fig. 5 representation of a fuse in a further embodiment; Fig. 6 representation of a fuse in a further embodiment with illustration of the stages when the fuse is triggered (partial figures A to C); and Fig. 7 representation of a fuse in a further embodiment with illustration of the stages when the fuse is triggered (partial figures A to D). DETAILED DESCRIPTION OF THE EMBODIMENTS

[0070] Fig. 1 schematically illustrates a battery module 100 according to the invention with a housing 101, wherein a plurality of cylindrical round cells are provided as energy storage cells 102 within the housing 101. The illustration shows a plan view of the end faces of the energy storage cells 102, which are combined in the form of a battery block, for example by means of a cell holder (not shown). The energy storage cells 102 can be connected to one another in parallel and / or in series, depending on the application. The negative potential and the positive potential of the interconnected energy storage cells 102 are connected to a negative busbar 103 and a positive busbar 104, respectively. The busbars 103 and 104 are each connected via a power line 105 and 106 to a connector plug 107, which forms the housing's external contact.To protect against short circuits, a fuse 10 is inserted between one of the connecting bars, in this case the positive connecting bar 104, and the power line 106 leading to the connecting plug 107. Reference numeral 10 here represents a fuse according to the invention, which can also be designed, for example, according to the embodiments 20, 30, 40, 50, or 60 explained below. According to the invention, the fuse 10 comprises a stranded wire and is mechanically flexible. This mechanical flexibility allows the fuse 10 to compensate for mechanical tolerances. Furthermore, it can yield without being damaged in the event of changes in the length or volume of elements of the battery module 100, which may be thermally or mechanically induced.

[0071] Fig. 2 Illustrates a first possible embodiment of the fuse 10, in which the stranded wire 11 forms the fuse element. The stranded wire can be made of conventional thin fuse elements. The individual fuse elements can be twisted or braided, for example. This produces a flexible stranded wire with a defined melting behavior and can be used as a fuse for overcurrent or short circuits.

[0072] In this exemplary embodiment, the ends of the fuse element 11 or the stranded wire are provided with cable lugs 12. Using the cable lugs 12, the fuse can be mechanically and electrically connected to mounting points 110 of the battery module (not shown here). Other connection techniques are also conceivable, such as flat plugs or direct welding of the ends. Compacting the ends of the stranded wire 11 with or without a through-hole for screwing is also possible.

[0073] Figure 2A shows the installed state of the fuse 10 at mounting points 110 in the battery module. In this way, the fuse can, for example, bridge a connector of the battery module on one side and the interconnected energy storage cells on the other side.

[0074] Part 2B indicates the occurrence of an overcurrent 99, which causes the fuse 10 to blow. The fuse element 11 heats up due to the overcurrent and melts, as shown in Part 2C. The ends of the flexible fuse element 11 fall downward due to gravity. This increases the length of any arc that may have formed, so that the arc is quickly extinguished.

[0075] Fig. 3 shows a further embodiment of a fuse 20. Comparable to the embodiment of Fig. 2 The fuse 20 is formed by a flexible stranded wire as a fuse element 11, with cable lugs 12 attached to the ends of the fuse element 11. Several ceramic beads 13 are mounted on the fuse element 11, as indicated in Figure 3A. Figure 3B shows the assembled state of the fuse 20, in which the cable lugs 12 are attached to fixed mounting points 110 of the battery module.

[0076] Partial Figure 3C indicates the occurrence of an overcurrent 99, which leads to the triggering of the fuse 20. The overcurrent 99 heats up the fuse element 11 and melts. As shown in Partial Figure 3D, the severed ends of the fuse element 11 fall downward, further assisted by the falling ceramic beads 13. The arc zone between the ends of the molten fuse element 11 rapidly expands, and any arc that may have formed is extinguished.

[0077] Fig. 4 illustrates a further embodiment of a fuse 30. Here, too, the fuse 30 comprises a flexible stranded wire as a fuse element 11, at both ends of which cable lugs 12 are attached for attaching the fuse to mounting points (not shown here) of a battery module. Furthermore, this embodiment is characterized by a spiral spring 14 arranged in the longitudinal direction of the fuse element 11 and extending over the entire length of the fuse element 11. The spiral spring 14 is firmly connected to the fuse element 11 at several points, in that the spiral spring 14, in this embodiment, passes through the fuse element 11 with each spring turn.

[0078] Partial Figure 4A shows the initial state of the fuse 30 in the unassembled state. Partial Figure 4B shows the assembled state of the fuse 30, in which the cable lugs 12 are attached to mounting points of the battery module (not shown here), and the coil spring 14 is subjected to mechanical tension by pulling the fuse 30 apart during its assembly.

[0079] Sub-Figure 4C illustrates the occurrence of an overcurrent 99, which leads to the triggering of the fuse 30. The fuse element 11 heats up and melts. The fuse element 11 has a lower resistance than the coil spring 14, which is, for example, a steel spring. The current therefore flows primarily through the fuse element 11, so that the fuse element 11 melts first. The current then also flows through the coil spring 14, so that the coil spring 14 also melts, since it can only carry a small amount of current. As illustrated in Sub-Figure 4D, after the melting, the separated parts of the coil spring 14 very quickly pull the melted ends of the fuse element 11 apart, thus extinguishing any arc that may have occurred.

[0080] Fig. 5 illustrates a further embodiment of a fuse 40 with a stranded wire as the fuse element 11. Cable lugs 12 or, if appropriate, other connecting elements for attaching the fuse 40 to fixed mounting points 110 of the battery module are provided at the ends of the fuse element 11. A spring element 15 is fixed to an external suspension point 16 in the battery module on one side. On the other side, the spring element 15 acts perpendicularly with respect to the longitudinal extent of the fuse element 11 on the fuse element 11 in the mounted state and puts the fuse element under tension. Instead of the spiral spring 15 shown here, other spring elements can also be used, for example a leaf spring or springy housing structural components. If the fuse element 11 melts during an overcurrent event, the arc zone is pulled apart by the force of the spring element 15 or, depending on the design, compressed.

[0081] Fig. 6 illustrates a further, particularly preferred embodiment of a fuse 50. Here, too, a stranded wire forms the fuse element 11. Cable lugs 12 are provided at both ends of the fuse element 11 for the electrical and mechanical connection of the fuse element 50 to the corresponding mounting points 110 of the battery module. In this embodiment, two coil springs 17 act from different directions in a vertical direction on the fuse element 11. The coil springs 17 are attached to opposing structures 18 of the battery module, in particular the battery housing, so that the spring forces act on the fuse element 11 in different directions when the fuse element 50 is installed (partial figure 6A).

[0082] Figure 6B illustrates the occurrence of an overcurrent 99, which leads to the triggering of the fuse 50. The fuse element 11 melts, and the two coil springs 17 pull the ends of the melted fuse element 11 in opposite directions according to the acting spring forces, so that the ends of the stranded wire or the fuse element 11 are very quickly pulled out of the melting zone. Any arc that may have formed is thus extinguished particularly quickly (Figure 6C).

[0083] Fig. 7 illustrates a preferred embodiment of a fuse in another basic embodiment of the fuse 60, in which, in addition to a fusible conductor 62, a flexible line section 61 is provided, which is formed by a stranded wire. The flexible line section 61 is designed, for example, as a stranded copper wire or as a strand made of a plurality of copper wires. This stranded copper wire 61 primarily forms the flexible element of the fuse 60, so that the mechanical flexibility of the fuse 60 can compensate for mechanical tolerances of the battery module and, at the same time, ensures flexibility in the event of changes in length or volume, which may be caused thermally and / or mechanically, without damaging the fuse 60.

[0084] In addition to the stranded wire or copper strand 61 (flexible conductor section), a fusible element 62 is provided. This element can preferably also be a stranded wire made of fusible conductor wires. In other embodiments, however, the fusible element 62 can also be a rigid fusible element, such as a stamped copper part.

[0085] The flexible copper strand 61 and the fusible element 62 are connected in series with each other by a connecting element 63, for example, a conventional butt connector or, in other designs, by welding. The copper strand 61 has a higher current-carrying capacity than the fusible element 62, so that in the event of an overcurrent, the fusible element 62 melts first.

[0086] Cable lugs 12 are provided at the free end of the copper strand 61 and the free end of the fuse element 62, with which the fuse 60 can be mounted in a battery module. In the embodiment shown here, the section with the flexible copper strand 61 is spanned by a spiral spring 64. This spiral spring 64 runs parallel to the copper strand 61 when tensioned.

[0087] Partial Figure 7A shows the unassembled state of the fuse 60, in which the coil spring 64 (tension spring) is in a relaxed state. Partial Figure 7B shows the fuse 60 in the assembled state, with the two cable lugs 12 mechanically and electrically connected to fixed mounting points 110 within the battery module. Assembly is performed in such a way that the fuse 60 is tensioned. In particular, the coil spring 64 is tensioned, so that the flexible line section formed by the copper strand 61 is under tension.

[0088] In the embodiment illustrated here, the fuse element 62 is also designed as a flexible conductor, in particular as a stranded wire made of thin fuse wires. Due to the tensioned mounting of the fuse element 60, the fuse element 62 also stretches in this embodiment. The flexibility of the fuse element 62 provided in this embodiment by using a stranded wire as the fuse element is not absolutely necessary. However, a flexible design of both the supply line or the stranded copper wire 61 and the fuse element 62 is particularly advantageous, as this further increases the mechanical flexibility of the fuse element 60.

[0089] Sub-figure 7C illustrates the occurrence of an overcurrent 99, which leads to the triggering of the fuse 60. Due to the overcurrent 99, the fuse element 62 heats up to such an extent that it melts. The copper strand 61 forming the current supply line remains intact due to its dimensioning. After the fuse element 62 is severed or melted, the coil spring 64, which lies above the flexible wire strand or the copper strand 61, contracts and very quickly pulls the separated ends of the fuse element 62 apart, so that any arc that may have formed is extinguished very quickly.

[0090] In the various fuse designs illustrated here, the fuse element 11, 62 and, if applicable, the flexible supply line or the copper strand 61 can be additionally insulated with ceramic beads. This additional insulation is particularly suitable for the Fig. 5 , 6 and7 shown designs.

[0091] The described fuses can be used particularly in battery modules to prevent the risk of fire, particularly due to externally induced short circuits, for example, during assembly. The fuses described result in very rapid shutdown of the battery module. The fuses are primarily used for high-current protection, with the nominal value for triggering the fuse advantageously being in a range between 300 and 500 amperes, for example, 300 amperes.

Claims

1. Battery module (100) comprising a housing (101), at least one connection element (107), in particular a connection plug, and a plurality of electrochemical energy storage cells (102) within the housing, wherein the battery module comprises at least one fuse (10; 20; 30; 40; 50; 60) which has a fusible conductor (11; 62), characterized by the following feature: a. the fuse (10; 20; 30; 40; 50; 60) comprises a wire strand (11; 61), which is formed from a plurality of individual wires, and two connections (12) for attachment to mounting points (110) in the battery module (100).

2. Battery module according to Claim 1, having the following additional feature: a. the fuse (10; 20; 30; 40; 50; 60) is designed for a nominal current in a range between 10 and 1000 amps, preferably between 200 and 500 amps.

3. Battery module according to Claim 1 or Claim 2, having the following additional feature: a. the fuse (10; 20; 30; 40; 50; 60) comprises cable lugs and / or plug-in connectors and / or wire end sleeves as connections (12) for attachment to the mounting points (110) in the battery module (100).

4. Battery module according to one of the preceding claims, having the following additional feature: a. the wire strand (11) is the fusible conductor (11).

5. Battery module according to Claim 4, having the following additional feature: a. individual wires of the wire strand (11) are made of a metallic material; b. the metallic material comprises silver and / or tin and / or copper.

6. Battery module according to Claim 4 or Claim 5, having the following additional feature: a. the fusible conductor (11) has a length of at least 2 cm.

7. Battery module according to one of Claims 4 to 6, having at least one of the following additional features: a. the wire strand (11) is surrounded by an electrically insulating material, which is mechanically flexible; b. the electrically insulating material is formed by a ceramic material, in particular by ceramic beads (13).

8. Battery module according to one of Claims 4 to 7, having at least one of the following additional features: a. the battery module or the fuse (30; 40; 50) comprises at least one means (14; 15; 17) for pulling apart parts of the wire strand (11) after they have melted through; b. the at least one means (14; 15; 17) for pulling apart parts of the wire strand (11) is at least one spring element; c. the at least one spring element is at least one helical spring.

9. Battery module according to Claim 8, having at least one of the following additional features: a. the at least one means (14) for pulling apart parts of the wire strand (11) acts in the longitudinal direction of the wire strand; b. the means (14) for pulling apart parts of the wire strand (11) is a helical spring which extends in the longitudinal direction of the wire strand and is mechanically connected to the wire strand at least at one point.

10. Battery module according to Claim 8, having at least one of the following additional features: a. the at least one means (15; 17) for pulling apart parts of the wire strand (11) acts perpendicularly in relation to the longitudinal extent of the wire strand; b. the at least one means (15; 17) for pulling apart parts of the wire strand (11) is at least one spring element, preferably two spring elements; c. the at least one means (17) for pulling apart parts of the wire strand is realized by two spring elements, which act on different portions of the wire strand (11).

11. Battery module according to one of Claims 1 to 3, having at least one of the following additional features: a. the fuse (60) comprises, in addition to the fusible conductor (62), a mechanically flexible electrical line portion (61), which is formed by the wire strand (61); b. the mechanically flexible line portion (61) which is formed by the wire strand is under bias, in particular under spring tension, in the mounted state; c. the bias, in particular the spring tension, acts in the longitudinal direction of the mechanically flexible electrical line portion (61) and causes the mechanically flexible electrical line portion (61) to contract when the fusible conductor (62) melts through.