Busbar current interruption device, battery module, battery pack, and vehicle

Abstract

A busbar current interruption device (20) adapted for electrically connecting two battery cells (2) within a battery module (1). The busbar current interruption device (20) comprises a busbar member (22) comprising a first terminal end portion (23), a second terminal end portion (24), and an intermediate portion (25) extending between the first and second terminal end portions (23, 24). The intermediate portion (25) comprises a plurality of through-holes (26, 27, 28) arranged so as to form at least three fuse portions (41, 42, 43, 44) configured to melt in a sequential order. The least three fuse portions (41, 42, 43, 44) comprises a first fuse portion (41) configured to melt last to thereby permanently break an electrical circuit through the busbar member (22). Said first fuse portion (41) has a length (L1), as seen along an electrical path therethrough, which is greater than a length (L2, L3) of each of the other fuse portions of the at least three fuse portions (41, 42, 43, 44).

Description

[0001] BUSBAR CURRENT INTERRUPTION DEVICE, BATTERY MODULE, BATTERY PACK, AND VEHICLE

[0002] TECHNICAL FIELD

[0003] The present disclosure relates in general to a busbar current interruption device adapted for electrically connecting two battery cells within a battery module. The present disclosure further relates in general to a battery module and a battery pack, respectively. Moreover, the present disclosure relates in general to a vehicle.

[0004] BACKGROUND

[0005] The electrification of vehicles has led to great focus on the development of improved energy storage devices for powering propulsion units of vehicles. Such energy storage devices require many battery cells to achieve desired capacity. The most frequently used battery cells today for this purpose are lithium-ion battery cells.

[0006] An energy storage device used for powering a vehicle may comprise one or more battery packs. In case the energy storage device comprises a plurality of battery packs, these may be connected in series and / or in parallel. Each battery pack may typically comprise a plurality of battery modules connected in series and / or in parallel. A battery module typically comprises multiple battery cells connected in series and / or parallel, partly or fully encased in a mechanical structure. Other configurations of energy storage devices are also possible, if desired. For example, it is also possible to arrange individual battery cells in a battery pack, without the use of modules.

[0007] Short circuits in energy storage devices, such as described above, can result in a fire. The risk is increased with increasing voltage and thus, for example, increases with increasing number of battery cells connected in series. The risk of fire caused by external short circuit may be prevented by a current interruption device arranged for example at a terminal of the energy storage device. This may for example be achieved by a pack fuse. Internal short circuits within the energy storage device might however not be disconnected by such a fuse. It has therefore previously been proposed to arrange a busbar current interruption device also at a battery module terminal level to thereby increase safety. Moreover, it is also previously known to arrange a current interruption device inside an individual battery cell. However, a current interruption device arranged inside an individual battery cell is typically only designed to protect the individual cell in case of overpressure and / or internal short circuit within or over the battery cell.

[0008] It would be desirable to be able to arrange a busbar current interruption device also within a battery module, outside of the individual battery cells. This would not only further increase the safety of the battery module, but could also greatly facilitate meeting the current and future legislative requirements for shipping of battery modules. This would in turn make it easier to ship battery modules for the purpose of serving as replacement parts to already existing energy storage devices. The available space within a battery module to accommodate a busbar current interruption device is however limited and it may be difficult to ensure that an electrical circuit within the battery module may be safely broken.

[0009] US 2014 / 0315051 Al discloses an example of a battery module comprising a plurality of rechargeable batteries and a busbar that electrically connects the rechargeable batteries. The busbar includes a first fuse part and a second fuse part separated from each other in a width direction of the busbar by a curved fuse groove, said curved fuse groove being formed at the center in the length direction of the busbar. It is described that, since current has a characteristic that it flows through the shortest path, current does not prefer to flow through the fuse groove but instead flows through the first and second fuse parts. When an overcurrent is generated, the first and second fuse parts are therefore melted before the curved fuse groove. Upon melting of the curved fuse groove, the current is blocked.

[0010] SUMMARY

[0011] The object of the present invention is to provide a current interruption device which may be arranged to connect two battery cells within a battery module and that provides increased safety when breaking an electrical circuit through the current interruption device.

[0012] The object is achieved by the subject-matter of the appended independent claim(s).

[0013] In accordance with the present disclosure, a busbar current interruption device adapted for electrically connecting two battery cells within a battery module is provided. The busbar current interruption device comprises a busbar member. The busbar member comprises a first terminal end portion, a second terminal end portion, and an intermediate portion extending between the first terminal end portion and the second terminal end portion. The intermediate portion comprises a plurality of through-holes arranged so as to form at least three fuse portions configured to melt in a sequential order. Said at least three fuse portions comprises a first fuse portion configured to be the fuse portion that melts last to thereby permanently break an electrical circuit through the busbar member. Each of the at least three fuse portions has a length as seen along an electrical path through the respective fuse portion. The length of the first fuse portion is greater than the length of each of the other fuse portions of the at least three fuse portions.

[0014] By means of the herein described busbar current interruption device, an electrical circuit within an energy storage device comprising a plurality of rechargeable battery cells connected in series (such as a battery module for a vehicle), may safely be broken in case of overload and / or risk for internal short circuit. Still the busbar current interruption device may efficiently operate to electrical connect two battery cells during intended normal operation of the energy storage device without unduly lowering the performance of the energy storage device.

[0015] This is achieved by the busbar member comprising at least three fuse portions configured to melt in a sequential order, i.e. one after another. In general, when a fuse portion is subjected to a current above a threshold for which it has been designed, the temperature in the fuse portion will increase to such a temperature at which the material of the fuse portion will melt, which in turn is intended to lead to break the fuse portion such that current no longer can flow therethrough. Melting of a fuse portion leads to generation of gas which may also contain metal evaporated from the fuse portion. In some cases, a spray of molten metal may also occur. Moreover, melting of the fuse portion may lead to formation of an electrical arc, which in turn may ignite a plasma. Evaporated metal (or even molten metal particles) may be ionized by the electrical arc, which in turn may lead to the plasma being sustained for a longer period of time. When fuse portions are configured to melt in a sequential order, as in the busbar current interruption device according to the present disclosure, less material needs be melted at the same time. This in turn enables gas generated during melting of a fuse portion being able to spread over a larger volume / escape from the region of the fuse portions before the next fuse portion melts. And importantly, less material needs to be melted at the final stage of permanently breaking the electrical circuit (i.e. melting of the fuse portion configured to melt last) compared to if all fuse portions were configured to break at essentially the same time. Furthermore, in view of the fuse portion being configured to melt last being longer than each of the other fuse portions of the at least three fuse portions, an electrical arc and possible sparks generated when said fuse portion melts can be more quickly quenched as a result of the increased distance between remaining solid metallic material. Thus, the possibilities for a plasma to sustain are considerably reduced. This in turn increases the safety of the busbar current interruption device as such, and thus also of the battery cells electrically connected by the busbar current interruption device.

[0016] Moreover, in view of the configuration of the busbar member with its at least three fuse portions, the busbar current interruption device may be made small and compact so as to fit into a battery module. In fact, it may be used as a replacement of a conventional busbar electrically connecting two adjacent cells within a battery module.

[0017] The busbar current interruption device may also be produced at a relatively low cost since the at least three fuse portions may be formed in the busbar member by e.g., stamping (or similar processes) to obtain the plurality of through-holes.

[0018] The safety increases with increasing length of the fuse portion configured to melt last. Therefore, the length of the first fuse portion may be at least 10% greater, preferably at least 25% greater, than the length of each of the other fuse portions of the at least three fuse portions.

[0019] The first fuse portion may not only have a different length than the length of each of the other fuse portions of the at least three fuse portions. The first fuse portion may suitably also have a cross sectional area which is different from a cross sectional area of each of the other fuse portions of the at least three fuse portions. This allows for tailoring the resistance of the first fuse portion relative to the resistance of each of the other three fuse portions. This may be made both to ensure a suitable distribution of current flow between the different fuse portions during normal intended operation of the busbar current interruption device (i.e. before it is designed to break the electrical circuit) as well as to ensure the order and timing of melting of the different fuse portions of the at least three fuse portion. Depending on the length of the first fuse portion compared to the length of the other fuse portions, the first fuse portion may have a greater or smaller cross sectional area than a cross sectional area of each of the other fuse portions of the at least three fuse portions.

[0020] The busbar current interruption device may further comprise a casing through which the busbar member extends. More specifically, the busbar member may extend through the casing so that the first terminal end portion and the second terminal end portion are arranged outside of the casing, whereas each of the at least three fuse is arranged inside the casing. The casing comprises at least one exhaust opening configured to allow escape of vapor from an interior of the casing. The casing serves the purpose of protecting sensitive constituent components arranged in the vicinity of the busbar current interruption device from electrical arcs and / or spraying molten metal generated during melting of the at least three fuse portions. This in turn increases the safety of the energy storage device, such as a battery module, in which the busbar current interruption device is arranged during its intended use. The exhaust opening of the casing ensures that vapor may escape from the interior of the casing to thereby reduce the risk of an internal pressure reaching so high that the casing itself may explode.

[0021] The casing may further comprise an exhaust channel whose outlet is formed by the at least one exhaust opening. In such a case, the exhaust channel may be arranged so as to direct vapor escaping from the interior of the casing, via the at least one exhaust opening, in a direction substantially perpendicular to a longitudinal extension of each of the first terminal end portion and the second terminal end portion. Thereby, vapor escaping from the interior of the casing will be directed in a controlled direction, other than towards the where the terminal end portions are connected to a respective cell terminal. This further improves the safety of the energy storage device in which the busbar current interruption device is arranged during its intended use.

[0022] The casing may comprise a first exhaust channel and a second exhaust channel, each having an outlet formed by a respective exhaust opening configured to allow vapor to escape from the interior of the casing. In such a case, the first and second exhaust channels, with their respective exhaust openings, may be arranged to direct vapor escaping from the interior of the casing in opposing directions as seen in relation to the busbar current interruption device. Thereby, less vapor generated during melting of the at least three fuse portions will be directed in the same direction when leaving the busbar current interruption device. This in turn improves safety of the energy storage device, such as a battery module, in which the busbar current interruption device may be arranged.

[0023] The busbar current interruption device may further comprise a separator arranged to extend through a first through-hole of the plurality of through-holes, said first through-hole separating the first fuse portion from an adjacent fuse portion of the at least three fuse portions. The purpose of such a separator is to reduce the risk of an electrical arc being formed between the adjacent fuse portion and the first fuse portion, and / or spraying of molten metal towards the first fuse portion, when the adjacent fuse portion melts. This in turn further increases safety of the busbar current interruption device. Suitably, each of the plurality of through-holes may have a separator extending therethrough. The separator, or separators, may optionally be an integral part of the casing. The first terminal end portion may have a longitudinal extension parallel to a longitudinal extension of the second terminal end portion. Thereby, the busbar member may have a substantially U-shaped configuration. This in turn allows for a larger intermediate portion, and thus also more space for the at least three fuse portions, while still being able to fit between two adjacent battery cells within for example a battery module. Moreover, this also makes it easier to fit the busbar current interruption device into the limited available space of a battery module also in situations where the busbar current interruption device comprises a casing.

[0024] In case the first terminal end portion has a longitudinal extension parallel to a longitudinal extension of the second terminal end portion, the at least three fuse portions may be arranged at different distances from a free end of each of the first and second terminal end portions, with the first fuse portion being arranged furthest away from the free ends of the first and second terminal end portions, respectively. This allows for the fuse portion being configured to melt last to be arranged furthest away from the cell terminals connected by the busbar current interruption device when it is arranged to connect two battery cells, which is advantageous for safety reasons. It also means that the current has to travel a longer electrical path when passing through the first fuse portion compared to the other fuse portions of the at least three fuse portions. Moreover, this also makes it easier to make the first fuse portion longer than each of the other fuse portions without having to provide a complex design of the fuse portions, which contributes to improved abilities for consistent results during production and thereby also intended performance when in use.

[0025] The busbar current interruption device described herein may be configured to permanently break an electrical circuit through the busbar member at voltages up to at least 1000 V. Additionally, or alternatively, the busbar current interruption device described herein may be configured to permanently break an electrical circuit through the busbar member at currents equal to or above 800 A. This makes it suitable for use in battery modules to be used in vehicles, such as medium-duty or heavy-duty vehicles.

[0026] The busbar current interruption device may suitably be designed to permanently break an electrical circuit in a relatively short period of time. For example, the configuration of the at least three fuse portions may suitably be selected to permanently break an electrical circuit through the busbar member in less than 100 ms, preferably in equal to or less than 60 ms. This improves the safety of a battery module in which the busbar current interruption device may be arranged since it reduces the risk of individual battery cells being damaged. The present disclosure further relates to a battery module comprising a plurality of battery cells connected in series. The battery module further comprises the busbar current interruption device described above. The busbar current interruption device is arranged to electrically connect two adjacent battery cells of the plurality of battery cells.

[0027] The busbar current interruption device of the battery module may suitably be configured to permanently break an electrical circuit therethrough in a time shorter than a time that each of the two adjacent battery cells, electrically connected by the busbar current interruption device, can withstand.

[0028] The present disclosure also relates to a battery pack comprising a plurality of battery modules, wherein at least one of the plurality of battery modules is a battery module as described above. In other words, at least one of the plurality of battery modules of the battery pack comprises a busbar current interruption device as described herein.

[0029] The present disclosure also relates to a vehicle comprising a battery module as described above. In other words, the vehicle comprises a battery module comprising the herein described busbar current interruption device.

[0030] The vehicle may be medium-duty or heavy-duty vehicle, but is not limited thereto. The vehicle may be a fully electric vehicle (such as a battery electric vehicle, BEV), a hybrid vehicle (such as a plug-in hybrid vehicle, PHEV, or a mild hybrid vehicle, mHEV), or a fuel cell vehicle.

[0031] BRIEF DESCRIPTION OF DRAWINGS

[0032] Fig. 1 illustrates a partly exploded perspective view of an example of a previously known battery module,

[0033] Fig. 2 illustrates a perspective view of one example of a battery module comprising a busbar current interruption device according to a first exemplifying embodiment of the present disclosure, Fig. 3 illustrates a perspective view of a second exemplifying embodiment of the herein described busbar current interruption device,

[0034] Fig. 4 illustrates a top view of a first alternative of the busbar member of the busbar current interruption device shown in Figure 3,

[0035] Fig. 5 illustrates a top view of a second alternative of the busbar member of the busbar current interruption device shown in Figure 3,

[0036] Fig. 6 illustrates a cross sectional view of the busbar current interruption device shown in Figure 3,

[0037] Fig. 7 illustrates a top view of a busbar member of a third exemplifying embodiment of the herein described busbar current interruption device,

[0038] Fig. 8 illustrates a cross sectional view of a fourth exemplifying embodiment of the herein described busbar current interruption device, the cross sectional view taken in a plane of a top surface of the busbar member, and

[0039] Fig. 9 schematically illustrates a side view of an example of a vehicle.

[0040] DETAILED DESCRIPTION

[0041] The invention will be described in more detail below with reference to exemplifying embodiments and the accompanying drawings. The invention is however not limited to the exemplifying embodiments discussed and / or shown in the drawings, but may be varied within the scope of the appended claims. Furthermore, the drawings shall not be considered drawn to scale as some features may be exaggerated in order to more clearly illustrate the invention or features thereof.

[0042] In the present disclosure, a current interruption device is considered to mean a device configured to cut off an electrical circuit for the purpose of preventing an incident, such as a short circuit or overload. A current interruption device may be configured to cut off the electrical circuit temporarily or permanently. The busbar current interruption device as described herein belongs to the group of current interruption devices configured to permanently cut off an electrical circuit. Moreover, the busbar current interruption device as described herein may be considered to be a fuse-type current interruption device.

[0043] The term "fuse portion" is in the present disclosure considered to mean an electrically conducting portion configured to melt when subjected to a current above a predetermined threshold, thereby preventing current to flow through the fuse portion due to breaking of the electrical path.

[0044] The present disclosure relates to a busbar current interruption device adapted for electrically connecting two battery cells within an energy storage device, such as a battery module, during normal operation of the energy storage device. The busbar current interruption device has primarily been developed for the purpose of allowing to safely and quickly break an electrical circuit in case of overload or internal short circuit within a battery module comprising a plurality of rechargeable battery cells, particularly a plurality of rechargeable battery cells connected in series. The battery cells may for example be lithium-ion battery cells, sodium-ion battery cells, potassium-ion battery cells, but are not limited thereto. The busbar current interruption device may however advantageously also be used in other energy storage devices comprising a plurality of battery cells. Also in such a case, the busbar current interruption device is used for electrically connecting two battery cells. For example, the busbar current interruption device may be used for electrically connecting two rechargeable battery cells in a battery pack comprising a plurality of battery cells, without said battery cells being organized in battery modules. When battery cells are arranged in a battery pack without being arranged in battery modules, the battery cells may be described as freestanding (although they may be held in place by a frame structure or the like).

[0045] Furthermore, the busbar current interruption device has primarily been developed for use in high- voltage energy storage devices, such as energy storage devices of land-based vehicles. In particular, it has been developed for use in an energy storage device for a medium-duty or heavy-duty vehicle, such as trucks or busses. It may also be used in energy storage devices for other types of vehicles, such as lighter land-based vehicles, watercrafts or aircrafts. Furthermore, the herein described busbar current interruption device may be used in a large variety of other applications, such as stationary or non-stationary energy storage solutions for various purposes. Examples of such solutions include energy storage solutions for storing solar or wind energy, mobile charging stations for charging of vehicles, etc.

[0046] The busbar current interruption device according to the present disclosure comprises a busbar member. The busbar member is suitably may be made of metallic material having high conductivity, such as copper, a copper alloy, aluminum, an aluminum alloy, or copper-clad aluminum. The busbar member comprises a first terminal end portion, a second terminal end portion, and an intermediate portion. The first terminal end portion is configured to be electrically connected to a cell terminal of a first battery cell, whereas the second terminal end portion is configured to be electrically connected to a cell terminal of a second battery cell. Thus, the busbar member is configured for electrically connecting two battery cells. The intermediate portion extends between the first terminal end portion and the second terminal end portion. In other words, the intermediate portion electrically connects the first terminal end portion with the second terminal end portion of the busbar member. Each of the first and second terminal end portions extends longitudinally between a respective first free end and an opposing second end where it connects with the intermediate portion.

[0047] The intermediate portion of the busbar member comprises a plurality of through-holes (i.e. two or more through-holes). The plurality of through-holes are arranged such that at least three fuse portions are formed in the intermediate portion, said at least three fuse portions being configured to melt in a sequential order. A fuse portion melts when the temperature of the fuse portion reaches the melting temperature of the material from which it is formed. The amount of heat generated in a fuse portion is proportional to the square of the current, the resistance and the time the current flows, as given by Joule's first law. The heat generated in turn affects the temperature increase of the material of the fuse portion. Thus, a plurality of fuse portions, such as the at least three fuse portions according to the present disclosure, can be made to melt in a sequential order through designing the fuse portions to have different resistances. In other words, the intermediate portion comprises a plurality of through-holes arranged to form at least three fuse portions, wherein each of the at least three fuse portions has a resistance which is different from a resistance of each of the other fuse portions of the at least three fuse portions. It should here be noted that when different fuse portions, formed in the same busbar member as according to the present disclosure, have different resistance, there will inherently be a difference in the current flowing through the respective fuse portions during normal operation of the busbar current interruption device (i.e. during such operation at which it is not yet designed to break the electrical circuit therethrough). The fuse portion having the highest resistance will inherently have the lowest current flowing therethrough. In other words, the fuse portion having the highest resistance will carry less than the amount of current it would carry if the current would be divided equally between the at least three fuse portions.

[0048] The resistance of a fuse portion is dependent of its size as well as the resistivity. In view of the fuse portions being formed through formation of through-holes in the intermediate portion, the material of the fuse portions will be the same. Consequently, the resistivity of the different fuse portions will be substantially the same (assuming that any difference in resistivity resulting from potential differences in temperature between the different fuse portions is so small that it may be ignored). This in turn means that the resistance of a fuse portion is dependent of its size, i.e. the length along the electrical path through the fuse portion and the cross sectional area of the fuse portion as seen perpendicular to its length. More specifically, the resistance of a fuse portion is proportional to the ratio between length and cross-sectional area.

[0049] The at least three fuse portions of the busbar member of the herein described busbar current interruption device comprises a first fuse portion configured to be the fuse portion that melts last of the at least three fuse portions. Thus, the first fuse portion may have a resistance which is higher than a resistance of each of the other fuse portions of the at least three fuse portions. Since the first fuse portion is configured to melt last, the melting of the first fuse portion permanently breaks an electrical circuit through the busbar member, and thus also through the busbar current interruption device as such.

[0050] The reason for the herein described busbar current interruption device comprising at least three fuse portions (configured to melt in a sequential order) is to reduce the amount of material in the fuse portion which is configured to melt last, while still ensuring that the busbar current interruption device is able to carry sufficient current during normal use (i.e. before it is designed to break the electrical circuit). The amount of material that needs to be melted in the final stage is reduced with increasing number of fuse portions. However, it may be difficult to achieve sufficient production accuracy in terms of dimensions of the fuse portions in case of too many fuse portions being present. Insufficient production accuracy may lead to the produced busbar current interruption devices not providing consistent results when in use, and permanently breaking the electrical circuit at different conditions, which is not desirable. Therefore, the busbar member of the busbar current interruption device may suitably comprise 3-6 fuse portions, preferably 3-5 fuse portions. Irrespectively of the number of fuse portions, all of the fuse portions are arranged in the intermediate portion of the busbar member.

[0051] The first fuse portion of the herein described busbar current interruption device has a length which is greater than the length of each of the other fuse portions of the at least three fuse portions. The length of a fuse portion is in the present disclosure considered to mean a length (or average length in case of e.g., non-straight fuse portions) along the electrical path through the respective fuse portion. Albeit that the resistance of a fuse portion increases with increasing length in case of having the same cross sectional area, the primary reason for the first fuse portion having a greater length than the other fuse portions is to more quickly quench any electrical arc formed during melting thereof. A faster quench of any electrical arc when the fuse portion configured to melt last melts inherently leads to a safer breaking of the electrical circuit. The length of the first fuse portion may for example be at least 10% greater, preferably at least 25% greater, than the length of each of the other fuse portions of the at least three fuse portions. The ability to quickly quench any electrical arc formed increases with increasing length of the first fuse portion, and the upper limit for the length of the first fuse portion is in practice merely set by the ability to produce the at least three fuse portions with sufficient accuracy.

[0052] In view of the at least three fuse portions being formed in the busbar member by forming a plurality of (i.e. two or more) through-holes in the intermediate portion, the at least three fuse portions may be made to melt in a sequential order, and be given their respective lengths (as seen along the electrical paths therethrough), through selection of geometrical configurations, sizes and the arrangement of said through-holes. By way of example, by giving the through-hole separating the first fuse portion from an adjacent fuse portion the shape of a trapezoid with only two parallel sides (said sides forming edges of the respective fuse portions), the first fuse portion may be made longer than the adjacent fuse portion of the at least three fuse portions. As previously mentioned above, the through-holes may also be arranged to give the at least three fuse portions different widths, which in turn may affect their respective cross sectional areas and thereby also their respective resistance. Thus, the first fuse portion may have a cross sectional area, perpendicular to its length, which is different from a cross sectional area of each of the other fuse portions of the at least three fuse portions.

[0053] In addition to the busbar member described above, the busbar current interruption device according to the present disclosure may suitably comprise a casing. If so, the busbar member extends through the casing so that the first terminal end portion and the second terminal end portions are arranged outside of the casing. However, each of the at least three fuse portions are arranged inside the casing. This may suitably be achieved by the casing being arranged to substantially circumscribe, and thus also substantially enclose, the intermediate portion of the busbar member. The casing serves the purpose of protecting sensitive constituent components arranged in the vicinity of the busbar current interruption device from electrical arcs and / or spraying molten metal generated during melting of the at least three fuse portions. The casing however comprises at least one exhaust opening configured to allow vapor, generated inside the casing due to melting of the at least three fuse portions, to escape from the interior of the casing to the surroundings. The exhaust opening of the casing ensures that vapor may escape from the interior of the casing to thereby reduce the risk of an internal pressure reaching so high that the casing itself may explode. The at least one exhaust opening may form an outlet of an exhaust channel formed in the casing. Such an exhaust channel may suitably be arranged so as to direct vapor escaping from the interior of the casing, via the at least one exhaust opening, in a direction substantially perpendicular to a longitudinal extension of each of the first and second terminal end portions.

[0054] According to one alternative, the casing comprises a first exhaust channel and a second exhaust channel, each having an outlet formed by a respective exhaust opening configured to allow escape of vapor from the interior of the casing. In such a case, the first and second exhaust channels, with their respective exhaust opening, are arranged to direct vapor escaping from the interior of the casing in opposing directions as seen in relation to the busbar current interruption device. Such opposing directions may each be substantially perpendicular to a longitudinal extension of each of the first and second terminal end portions, and could be in a plane parallel to a plane of a top surface of the busbar member (in case the busbar member has a plate-like configuration) or angled thereto with an angle of up to e.g., 45° (preferably equal to or less than 30°).

[0055] The busbar current interruption device may further comprise one or more separators arranged to extend through a respective through-hole of the plurality of through-holes of the intermediate portion of the busbar member. Suitably, a separator is arranged to extend through a first through- hole of the plurality of through-holes, said first through-hole separating the first fuse portion from an adjacent fuse portion of the at least three fuse portions. Each of the one or more separators may each be an integral part of the casing, or may be a separate constituent component of the busbar current interruption device. The purpose of the one or more separators is to reduce the risk of an electrical arc being formed between adjacent fuse portions and the first fuse portion, and / or spraying of molten metal therebetween, when the adjacent fuse portions melt.

[0056] The casing of the herein described busbar current interruption device is intended to serve as a protective casing. The casing should thus be formed of a material which is electrically insulating. Moreover, the casing should preferably be made of a material having low weight. Therefore, the casing may suitably be made of a polymeric material. Examples of suitable materials include aramid, nylon or polyurethane, which may or may not be fiber reinforced. Other polymeric materials are also plausible. As previously mentioned, the separator (if present) may be an integral part of the casing and is in such a case formed of the same material as the casing. Naturally, the separator may be formed of the same material as the casing even if not being an integral part of the casing. In some battery modules, the distance between cell terminals of adjacent battery cells may be relatively small. In such cases, it may sometimes be difficult to obtain a sufficiently large intermediate portion to enable the desired sizes of the at least three fuse portions. To overcome said problem, the busbar member may be given a substantially U-shaped configuration (which may alternatively be described as a substantially C-shaped configuration). In such a case, the first terminal end portion would have a longitudinal extension which is substantially parallel to a longitudinal extension of the second terminal end portion.

[0057] In case the busbar member has a substantially U-shaped configuration as described above. The at least three fuse portions may be arranged at different distances from a free end of each of the first and second terminal end portions. More specifically, the first fuse portion may be arranged furthest away from the free ends of the first and second terminal end portions, respectively. Thereby, the fuse portion configured to melt last will be arranged furthest from the cell terminals of the battery cells connected by the busbar current interruption device when in use.

[0058] Figure 1 illustrates a partly exploded view of an example of a previously known battery module 1'. The battery module comprises a plurality of battery cells 2, here illustrated as prismatic battery cells. The battery cells 2 may for example be lithium-ion battery cells or sodium-ion battery cells, but are not limited thereto. The illustrated battery module 1' comprises a total of twelve battery cells 2.

[0059] However, the number of battery cells 2 may vary depending on the requirements of the intended use of the battery module 1'. The battery cells 2 may typically be stacked side-by-side, as shown in the figure.

[0060] Each battery cell 2 comprises a first cell terminal 3 and a second cell terminal 4. The first cell terminal 3 may be a positive cell terminal, and the second cell terminal 4 may be a negative cell terminal, or vice versa. Within the battery module 1', two adjacent battery cells 2 may be electrically connected by a busbar 5. The battery cells 2 of the battery module 1' may typically be connected in series to obtain a desired voltage of the battery module 1' suitable for use in a vehicle. The busbars 5 may optionally be supported by a busbar support structure 6, as shown in the figure.

[0061] The battery cells 2 may be partly or fully encased by a mechanical structure 8 of the battery module 1'. The mechanical structure 8 may for example comprise a bottom structure 9, two opposing side panels 10, two opposing end plates 11, and a top cover 12, as shown in the figure. The bottom structure 9 may suitably comprise a temperature regulating circuit (not shown) configured for controlling the temperature of the battery cells 2 in the battery module 1'. Such a temperature regulating circuit may additionally or alternatively be incorporated in other parts of the mechanical structure 8, such as the side panels 10 and / or the end plates 11, if desired. The mechanical structure 8 may suitably be configured to hold the battery cells 2 in compression, for example to reduce potential swelling of the battery cells 2 during operation.

[0062] The busbar current interruption device according to the present disclosure may for example be used in the exemplified battery module 1' shown in Figure 1 through replacement of any one of the busbars 5 with the herein described busbar current interruption device.

[0063] Figure 2 illustrates a perspective view of an example of a battery module 1 according to the present disclosure. The battery module 1 comprises a busbar current interruption device 20 according to a first exemplifying embodiment of the present disclosure. It should be noted that a mechanical structure (compare with the mechanical structure 8 shown in Figure 1) of the battery module 1 has been omitted in the figure for brevity and clarity.

[0064] Like in the battery module 1' illustrated in Figure 1, the battery module 1 comprises a plurality of battery cells 2, stacked side-by-side. Moreover, the battery cells 2 may be prismatic battery cells. Each battery cell 2 comprises a first cell terminal 3 and a second cell terminal 4. The first cell terminal 3 of one battery cell 2 is connected to the second cell terminal 4 of an adjacent battery cell 2 by a busbar 5. In other words, the battery cells 2 of the battery module 1 are connected in series. The battery module 1 further comprises a first module terminal 13 and a second module terminal 14.

[0065] As previously mentioned, the battery module 1 comprises a busbar current interruption device 20. The busbar current interruption device 20 is arranged to electrically connect two of the battery cells 2 within the battery module 1. In other words, the busbar current interruption device 20 is used for electrically connecting two adjacent battery cells 2, instead of a busbar 5 that is typically used for electrically connecting two other battery cells 2 to each other. The busbar current interruption device 20 may be arranged to electrically connect the two battery cells 2 that are arranged in the middle of the battery module 1, as shown in the figure, but the present disclosure is not limited thereto. It should also be noted that the battery module 1 may comprise more than one busbar current interruption device 20, if desired.

[0066] The busbar current interruption device 20 comprises a busbar member 22 having a first terminal end portion 23 and a second terminal end portion 24. The first and second terminal end portions 23, 24 are each connected to a respective cell terminal 3, 4 of two adjacent battery cells 2 when the busbar current interruption device 20 is arranged in the battery module 1, as shown in the figure. The busbar member 22 according to the first exemplifying embodiment has a substantially rectangular plate-like shape. In other words, the busbar member 22 may be regarded to have an outer shape substantially corresponding to a rectangular cuboid.

[0067] In addition to the busbar member 22, the busbar current interruption device 20 suitably also comprises a casing 30, as shown in the figure. In such a case, the busbar member 22 is arranged to extend through the casing 30 such that the first and second terminal end portions 23, 24 are arranged outside of the casing 30.

[0068] The busbar member 22 further comprises an intermediate portion 25 extending between the first and second terminal end portions 23, 24. In the exemplified embodiment of the busbar current interruption device 20, the intermediate portion 25 is arranged inside the casing 30, and is therefore not visible in the shown perspective view of the exemplified battery module 1. However, the dashed circle shown in the figure illustrates a top view of the intermediate portion 25 of the busbar member 22 in greater detail.

[0069] The intermediate portion 25 of the busbar member 22 comprises a first through-hole 26 and a second through-hole 27. The first and second through-holes 26, 27 are arranged such that a first fuse portion 41, a second fuse portion 42, and a third fuse portion 43 are formed in the intermediate portion 25. Furthermore, the first and second through-holes 26, 27 are arranged such that the three fuse portions 41, 42, 43 will melt in a sequential order. This may be achieved by arranging the through-holes 26, 27 such that the three fuse portions 41, 42, 43 will have different cross sectional areas as seen perpendicular to their respective length (which will be further described below) and / or different lengths. In other words, if assuming that the thickness of the busbar member 22 is substantially constant in the intermediate portion 25, the first and second through-holes 26, 27 may be arranged such that the width of the three different fuse portions 41, 42, 43 differ from each other, thereby resulting in different cross sectional areas of the three fuse portions 41, 42, 43. According to the exemplified embodiment, the second fuse portion 42 is configured to melt before the first fuse portion 41, and the third fuse portion 43 is configured to melt before the second fuse portion 42.

[0070] Moreover, as shown in the figure, the first and second through-holes 26, 27 in the intermediate portion 25 are arranged such that the first fuse portion 41 (i.e., the fuse portion configured to melt last) has a length LI which is greater than the length of each of the second and third fuse portions 42, 43 (the figure illustrating the length L3 of the third fuse portion 43). The length of the respective fuse portions 41, 42, 43 is here considered to correspond to the extension along the electrical path through the respective fuse portion 41, 42, 43. In the exemplified embodiment, each of the three fuse portions 41, 42, 43 are formed as straight fuse portions in the intermediate portion 25 and thus has a length parallel to the longitudinal extension of busbar member 22. The longitudinal extension of the busbar member 22 also coincides with a longitudinal extension of each of the first terminal end portion 23, the intermediate portion 25, and the second terminal end portion 24 in view of geometrical shape of the busbar member 22 according to the first exemplifying embodiment. The first fuse portion 41 may for example have a greater length than the each of the other fuse portions 42, 43 as a result of the first through-hole 26, which separates the first fuse portion 41 from the adjacent second fuse portion 42, having a shape of a trapezoid with only one pair of parallel sides, as shown in the figure. The second through-hole 27, which separates the second fuse portion 42 from the third fuse portion 43, may for example have a substantially rectangular shape, as shown in the figure, or a trapezoid shape similar to that of the first through-hole 26.

[0071] As previously mentioned, the busbar current interruption device 20 suitably comprises a casing 30. If, so, the casing 30 is arranged so as to circumscribe, and thereby enclose, at least the portion of the busbar member 22 where the three fuse portions 41, 42, 43 are arranged, i.e. the intermediate portion 25. The purpose of such a casing 30 is to increase safety by ensuring that the melting of the three fuse portion 41, 42, 43 does not risk damaging other components of the battery module 1, in which the busbar current interruption device 20 is arranged, which in turn could lead to short-circuit within the battery module 1 and / or overload of individual battery cells 2. However, melting of the three fuse portions will lead to generation of vapor. To ensure that the pressure inside the casing may not increase to such a degree that the casing itself may explode, the casing 30 comprises at least one (first) exhaust opening 32 configured to allow vapor to escape to the surroundings outside of the casing 30 in a preselected safe direction. The casing 30 may optionally also comprise a second exhaust opening 34 configured to allow escape of vapor from the interior of the casing 30, as shown in the figure.

[0072] Figure 3 illustrates a perspective view of a second exemplifying embodiment of the herein described busbar current interruption device 20. For the purpose of illustrating how the busbar current interruption device 20 may be arranged in an energy storage device, such as the battery module 1' shown in Figure 1 or the battery module 1 shown in Figure 2, parts of two adjacent battery cells 2 with their respective first / second cell terminals 3, 4 are illustrated by dotted lines. Like in the first exemplifying embodiment shown in Figure 2, the busbar current interruption device 20 comprises a busbar member 22 and a casing 30. The busbar member 22 comprises a first terminal end portion 23 and a second terminal end portion 24, each configured to be connected to a respective cell terminal 3, 4 of two battery cells 2 when the busbar current interruption device 20 is arranged in a battery module. The busbar member 22 further comprises an intermediate portion 25 extending between the first and second terminal end portions 23, 24. The busbar member 22 extends through the casing 30 such that the first and second terminal end portions 23, 24 are arranged outside of the casing 30, whereas the intermediate portion 25 is arranged inside the casing 30. Thus, the intermediate portion 25 is only partly visible in the figure (here visible through an exhaust opening 32, as will be further explained below, of the casing 30). The intermediate portion 25 will however be described in more detail below with reference to Figures 4 and 5.

[0073] However, unlike the first exemplifying embodiment shown in Figure 2, the busbar member 22 according to the second exemplifying embodiment of the busbar current interruption device 20 has a substantially U-shaped plate-like configuration. Thus, the first and second terminal end portions 23, 24 are arranged substantially in parallel so as to form the legs of such a U-shape, with the intermediate portion 25 connecting the first and second terminal end portions 23, 24 to each other. Described differently, the first terminal end portion 23 has a longitudinal extension substantially parallel to a longitudinal extension of the second terminal end portion 24. The longitudinal extension of the first and second terminal end portions 23, 24, respectively, is here considered to be the extension from their respective free ends 23a, 24a to where they connect to the intermediate portion 25.

[0074] The casing 30 circumscribes the intermediate portion 25 of the busbar member 22. The casing 30 comprises a first exhaust opening 32 and a second exhaust opening 34, each configured to allow escape of vapor from the interior of the casing. It should here be noted that although two exhaust openings 32, 34 are shown in the figure, the casing 30 may alternatively comprise a single exhaust opening or more than two exhaust openings configured to allow escape of vapor from the interior of the casing 30, if desired. Each of the first and second exhaust openings 32, 34 may form an outlet of a respective exhaust channel 33, 35 as will be described below with reference to Figure 6. The exhaust channels 33, 35 with their respective exhaust openings 32, 34 are configured to control the direction in which the vapor leaves the casing 30, and thus also any evaporated and / or molten metal that may be generated as a result of melting of fuse portions arranged in the intermediate portion 25. More specifically, vapor escaping from the interior of the casing will be directed in two opposing directions as seen in relation to the busbar current interruption device 20 as a result of the arrangement of the exhaust channels 33, 35 with their respective exhaust openings 32, 34.

[0075] Preferably, each of the exhaust channels 33, 35 with their respective exhaust openings 32, 34 may be arranged so as to direct vapor escaping from the interior of the casing 30 in a direction substantially perpendicular to a longitudinal extension of each of the first and second terminal end portions 23, 24. Moreover, the vapor may be directed in a plane substantially parallel to, or slightly angled relative to, a top plane of the busbar member 22. Naturally, the vapor escaping from the interior of the casing will, after passing the first and second exhaust openings 32, 34, spread out in the available volume. Thus, the directions in which the vapor is controlled to escape as described above shall be regarded to relate to the configuration and arrangement of the exhaust openings 32, 24 and their respective exhaust channels 33, 35. As shown in the figure, the first exhaust opening 32 may have a perimeter which is, at least partly, arranged in a plane Pl perpendicular to an imaginary straight line I passing through a first central point 23b of the first terminal end portion 23 and a second central point 24b of the second terminal end portion 24. Similarly, the second exhaust opening 34 may have a perimeter which is, at least partly arranged in a plane perpendicular to the imaginary straight line I.

[0076] Figure 4 illustrates a top view of a first alternative of the busbar member 22 of the second exemplifying embodiment of the busbar current interruption device 20 as shown in Figure 3. As previously mentioned, the busbar member 22 comprises a first terminal end portion 23, a second terminal end portion 24, and an intermediate portion 25 extending between the first and second terminal end portions 23, 24. The first terminal end portion 23 has a longitudinal extension which is substantially parallel to the longitudinal extension of the second terminal end portion 24. In other words, the busbar member 22 has a substantially U-shaped configuration.

[0077] The intermediate portion 25 comprises a first through-hole 26 and a second through-hole 27. The first and second through-holes 26, 27 are arranged such that a first fuse portion 41, a second fuse portion 42, and a third fuse portion 43 are formed in the intermediate portion 25. The first through- hole 26 separates the first fuse portion 41 from the second fuse portion 42. The second through-hole 27 separates the second fuse portion 42 from the third fuse portion 43. The first and second through- holes 26, 27 are arranged such that the three fuse portions 41, 42, 43 are configured to melt in a sequential order. This may be achieved by arranging the through-holes 26, 27 such that the three fuse portions 41, 42, 43 will have different resistances as a result of their respective sizes. As previously mentioned, the resistance of a fuse portion is proportional to the ratio between its length and cross sectional area. According to the illustrated exemplified embodiment, the first fuse portion 41 has a length LI, as seen along the electrical path therethrough, which is longer than a length L2 of the second fuse portion 42. Moreover, the second fuse portion 42 has a length L2 which is longer than the length L3 of the third fuse portion 43. Moreover, in the exemplified embodiment shown, the three fuse portions 41, 42, 43 are arranged substantially in parallel. The differences in length of the three fuse portions 41, 42, 43 is here a result of the first and second through-holes 26, 27 having the shape of a trapezoid with only one pair of parallel sides. Moreover, albeit not clearly visible in the figure, the fuse portions 41, 42, 43 have different widths, as seen perpendicular to its respective length LI, L2, L3, and thus also different cross sectional areas (assuming that the thickness of the busbar member 22 throughout the intermediate portion 25 is the same).

[0078] The arrangement of the through-holes 26, 27 is selected so that the first fuse portion 41 melts after each of the second fuse portion 42 and the third fuse portion 43 has melted. Moreover, the through- holes 26, 27 are arranged such that the second fuse portion 42 will melt after the third fuse portion 43, or such that the third fuse portion 43 will melt after the second fuse portion 42.

[0079] The fact that the first fuse portion 41 has a greater length LI than each of the other fuse portions 42, 43 may, depending on the cross sections of the respective fuse portions 41, 42, 43, result in the first fuse portion 41 having the highest resistance and thereby be configured to melt last. However, more importantly, the first fuse portion 41 is selected to be longer in order to more quickly quench any electrical arc that may be formed during melting of the fuse portions 41, 42, 43.

[0080] Furthermore, as shown in the figure, three fuse portions 41, 42, 43 are arranged at different distances from the free ends 23a, 24a of the first and second terminal end portions 23, 24. The first fuse portion 41 is arranged furthest away from each of the free end 23a of the first terminal end portion 23 and the free end 24a of the second terminal end portion 24.

[0081] Figure 5 illustrates a top view of a second alternative of the busbar member 22 of the second exemplifying embodiment of the busbar current interruption device 20 as shown in Figure 3. The second alternative of the busbar member 22 essentially corresponds to the first alternative of the busbar member 22 shown in Figure 4, except that it further comprises a third through-hole 28 and hence also a fourth fuse portion 44. The third through-hole 28 separates the third fuse portion 43 and the fourth fuse portion 44. As shown in the figure, the third and fourth fuse portions 43, 44 may have essentially the same lengths along the respective electrical paths therethrough. However, the third and fourth fuse portions 43, 44 may still be configured to melt in a sequential order, e.g., by having different cross sectional areas (as seen perpendicular to their respective lengths).

[0082] Figure 6 illustrates a cross sectional view of the second exemplifying embodiment of the herein described busbar current interruption device as seen in plane P2 of Figure 3. The plane P2 traverses one of the through-holes, more specifically the second through-hole 27, of the intermediate portion 25 of the busbar member 22. Moreover, the plane P2 is substantially perpendicular to the longitudinal extensions of each of the first and second terminal end portions 23, 24.

[0083] As shown in the figure, the casing 30 circumscribes the intermediate portion 25 of the busbar member 22. The casing 30 also comprises a first exhaust channel 33 whose outlet is formed by the first exhaust opening 33. The casing 30 also comprises a second exhaust channel 35 whose outlet is formed by the second exhaust opening 34. The first exhaust channel 33 may for example be separated from the second exhaust channel 35 by a partition wall 36. The exhaust channels 33, 35 with their respective exhaust openings 32, 34 are configured to control the direction in which the vapor escapes to the surroundings. More specifically, the first and second exhaust channels 33, 35, with their respective exhaust openings 32, 34, are arranged so as to direct vapor escaping from the interior of the casing 30 in two, opposing, directions as seen in relation to the busbar current interruption device 20. The opposing flow directions are illustrated by the arrows V in the figure. Vapor escaping from the interior of the casing 30 in the direction of the arrows V will be directed in a direction substantially perpendicular to the longitudinal extension of each of the first and second terminal end portions 23, 24.

[0084] As shown in the figure, the perimeter of the first exhaust opening is partly arranged in a plane Pl. The plane Pl is, as shown in Figure 3, perpendicular to an imaginary straight line I passing through a first central point 23b of the first terminal end portion 23 and a second central point 24b of the second terminal end portion 24.

[0085] The busbar current interruption device 20 according to the second exemplifying embodiment may further comprise a separator 38 extending through the through-hole 27, as shown in the figure. Moreover, although not visible in the figure, a similar separator may also be arranged in the first through-hole 26. The separator 38 is here illustrated as a separate component from the casing 30, but could alternatively be an integral part of the casing 30. The purpose of a separator arranged in any one of the through-holes 26, 27 is to reduce the risk for electrical arcs being formed between the fuse portions 41, 42, 43 during melting thereof as well as to avoid molten metal spraying therebetween.

[0086] Figure 7 illustrates a top view of a busbar member 22 of a third exemplifying embodiment of the herein described busbar current interruption device 20. The busbar member 22 shown in Figure 7 is similar to the busbar member shown in Figure 4, but has a different configuration of the first and second through-holes 26, 27 arranged in the intermediate portion 25. This in turn also leads to the three fuse portions 41, 42, 43 having a different configuration compared to the busbar member shown 22 in Figure 4. More specifically, the three fuse portions 41, 42, 43 are not all substantially straight and arranged in parallel. Instead, each of the first fuse portion 41 and the second fuse portion 42 has a substantially V-shaped longitudinal extension (as seen in the top view shown). However, the third fuse portion 43 has a straight longitudinal extension. The first through-hole 26 may be described as having a substantially V-shaped configuration, whereas the second through-hole 27 may be described to have a shape similar to that of a house gable. By giving the first fuse portion 41 a substantially V-shaped longitudinal extension, it may be made longer compared to if it would have a substantially straight longitudinal extension under the condition of substantially the same sizes of, and the distance between, the first and second terminal end portions 23, 24.

[0087] As can be seen from the figure, the first fuse portion 42 has a length LI, as seen along the electrical path therethrough, which is greater than the length L2 of the second fuse portion 42 as well as the length L3 of the third fuse portion L3. Moreover, the length L2 of the second fuse portion 42 is longer than the length L3 of the third fuse portion.

[0088] In the busbar member 22 shown in Figure 7, the cross sectional area of the third fuse portion 43 may be greater than the cross sectional area of the second fuse portion 42. Moreover, the cross sectional area of the second fuse portion 42 may be greater than the cross sectional area of the first fuse portion 41. The cross sectional areas of the respective fuse portions 41, 42, 43 is here regarded as perpendicular to their respective lengths LI, L2, L3.

[0089] The sizes of the three fuse portions 41, 42, 43 are selected such that they will melt in a sequential order. As previously mentioned, this may be achieved through selecting the respective sizes of the three fuse portions 41, 42, 43 such that the fuse portions will have different resistances, and the resistance of a fuse portion is proportional to the length divided by the cross sectional area. In addition to said busbar member 22 shown in Figure 7, the busbar current interruption device according to the third exemplifying embodiment may suitably further comprise a casing comprising at least one exhaust opening (for example a casing substantially similar to the casing 30 shown in Figures 3 and 6). Such a casing is however not illustrated in the figure for sake of brevity and clarity. When the busbar current interruption device according to the third exemplifying embodiment comprises a casing, the busbar member 22 shown in Figure 7 extends through the casing such that the first and second terminal end portions 23, 24 are arranged outside of the casing, whereas each of the three fuse portions 41, 42, 43 is arranged inside the casing. Moreover, the casing comprises at least one exhaust opening configured to allow escape of vapor from the interior of the casing. The busbar current interruption device according to the third exemplifying embodiment may further suitably comprise a first separator (compare with separator 38 shown in Figure 6) arranged to extend through the first through-hole 26, and preferably also a second separator arranged to extend through the second through-hole 27.

[0090] Figure 8 illustrates a cross sectional view of a fourth exemplifying embodiment of the herein described busbar current interruption device 20. The cross sectional view is taken in a plane of a top surface of the busbar member 22.

[0091] Like in the second and third exemplifying embodiments described above, the busbar member 22 comprises a first terminal end portion 23, a second terminal end portion 24 and an intermediate portion 25, and has a substantially U-shaped plate-like configuration. The intermediate portion 25 comprises a first through-hole 26 and a second through-hole 27 arranged so that a first fuse portion 41, a second fuse portion 42, and a third fuse portion 43 are formed in the intermediate portion 25 of the busbar member 22. The three fuse portions 41, 42, 43 are configured to melt in a sequential order, with the first fuse portion 41 configured to be the fuse portion that melts last.

[0092] Unlike the previously described exemplifying embodiments, the first fuse portion 41 has a substantially C-shaped configuration (as seen in a top view of the busbar member 22). Each of the second and third fuse portions 42, 43 however has a straight longitudinal extension, and are arranged in parallel. The first fuse portion 41 is thus longer than each of the second and third fuse portions 42, 43. The first through-hole 26 here has the shape of a trapezoid with only one pair of parallel sides, whereas the second through-hole 27 has a substantially rectangular configuration.

[0093] As shown in the figure, the busbar member 22 is arranged to extend through a casing 30 such that the first and second terminal end portions 23, 24 are arranged outside of the casing 30. The intermediate portion 25, and thus also the three fuse portions 41, 42, 43, are however arranged inside the casing 30. Albeit not visible in the cross sectional view shown, the casing comprises at least one exhaust opening configured to allow escape of vapor from the interior of the casing 30 (compare with Figures 3 and 6). Said exhaust opening may suitably form an outlet of an exhaust channel in the same manner as described above with reference to the second exemplifying embodiment.

[0094] The busbar current interruption device 20 according to the fourth exemplifying embodiment further comprises a separator 38 arranged to extend through the first through-hole 26. The separator 38 may suitably be configured to substantially fill up the first through-hole 26. Said separator 38 may be an integral part of the casing 30. Moreover, although not illustrated in the figure, a second separator may be arranged to extend through the second through-hole 27. The second separator, if present, may be also an integral part of the casing 30, if desired.

[0095] Figure 9 illustrates a side view of an example of a vehicle 100, here illustrated as a trailer tractor. The vehicle 100 may be a heavy-duty vehicle, such as a truck or a bus, but is not limited thereto. Furthermore, the vehicle 100 may be a fully electrical vehicle (e.g., a battery electric vehicle), a hybrid vehicle (e.g., a plug-in hybrid vehicle), or a fuel cell vehicle.

[0096] The vehicle 100 comprises one or more battery packs 50, schematically represented in the figure by dotted boxes. At least one of the battery packs 50 may comprise a battery module 1 according to the present disclosure, i.e. a battery module 1 comprising the herein described busbar current interruption device 20. Although not shown in the figure, a battery pack 50 of the vehicle 100 may additionally, or alternatively, comprise a plurality of battery cells 2 connected in series without being arranged in a battery module. In such a case, at least two of the battery cells 2 may be electrically connected to each other by a busbar current interruption device 20 according to the present disclosure.

Claims

CLAIMS1. A busbar current interruption device (20) adapted for electrically connecting two battery cells (2) within a battery module (1), the busbar current interruption device (20) comprising a busbar member (22) comprising: a first terminal end portion (23), a second terminal end portion (24), and an intermediate portion (25) extending between the first terminal end portion (23) and the second terminal end portion (24); wherein the intermediate portion (25) comprises a plurality of through-holes (26, 27, 28) arranged so as to form at least three fuse portions (41, 42, 43, 44) configured to melt in a sequential order, said at least three fuse portions (41, 42, 43, 44) comprising a first fuse portion (41) configured to be the fuse portion that melts last to thereby permanently break an electrical circuit through the busbar member (22), each of the at least three fuse portions (41, 42, 43, 44) having a length (LI, L2, L3) as seen along an electrical path through the respective fuse portion, and wherein the length (LI) of the first fuse portion (41) is greater than the length (L2, L3) of each of the other fuse portions of the at least three fuse portions (41, 42, 43, 44).

2. The busbar current interruption device (20) according to claim 1, wherein the length (LI) of the first fuse portion (41) is at least 10% greater, preferably at least 25% greater, than the length (L2, L3) of each of the other fuse portions of the at least three fuse portions (41, 42, 43, 44).

3. The busbar current interruption device (20) according to any one of claims 1 or 2, wherein the first fuse portion (41) has a cross sectional area, perpendicular to its length (LI), which is different from a cross sectional area of each of the other fuse portions of the at least three fuse portions (41, 42, 43, 44).

4. The busbar current interruption device (20) according to any one of the preceding claims, further comprising: a casing (30) through which the busbar member (22) extends so that the first terminal end portion (23) and the second terminal end portion (24) are arranged outside of the casing(30), whereas each of the at least three fuse portions (41, 42, 43, 44) is arranged inside the casing (30), said casing (30) comprising at least one exhaust opening (32, 34) configured to allow escape of vapor from an interior of the casing (30).

5. The bus bar current interruption device (20) according to claim 4, wherein the casing (30) further comprises an exhaust channel (33, 35) whose outlet is formed by the at least one exhaust opening (32, 34), said exhaust channel (33, 35) being arranged so as to direct vapor escaping from the interior of the casing (30), via the at least one exhaust opening (32, 34), in a direction substantially perpendicular to a longitudinal extension of each of the first terminal end portion (23) and the second terminal end portion (24).

6. The busbar current interruption device (20) according to any one of claims 4 or 5, wherein the casing (30) comprises a first exhaust channel (33) and a second exhaust channel (35), each having an outlet formed by a respective exhaust opening (32, 34) configured to allow escape of vapor from the interior of the casing (30), wherein the first exhaust channel (33) and the second exhaust channel (35), with their respective exhaust opening (32, 34), are arranged to direct vapor escaping from the interior of the casing (30) in opposing directions as seen in relation to the busbar current interruption device (20).

7. The busbar current interruption device (20) according to any one of claims 4 to 6, further comprising: a separator (38) arranged to extend through a first through-hole (26) of the plurality of through-holes (26, 27, 28), said first through-hole (26) separating the first fuse portion (41) from an adjacent fuse portion of the at least three fuse portions (41, 42, 43, 44); optionally wherein said separator (38) is an integral part of the casing (30).

8. The busbar current interruption device (20) according to any one of the preceding claims, wherein the first terminal end portion (23) has a longitudinal extension parallel to a longitudinal extension of the second terminal end portion (24).

9. The busbar current interruption device (20) according to claim 8, wherein the at least three fuse portions (41, 42, 43, 44) are arranged at different distances from a free end (23a, 24a) ofeach of the first and second terminal end portions (23, 24), and the first fuse portion (41) is arranged furthest away from the free ends (23a, 24a) of the first and second terminal end portions (23, 24), respectively.

10. The busbar current interruption device (20) according to any one of the preceding claims, wherein the busbar current interruption device (20) is configured to permanently break an electrical circuit through the busbar member (22) at voltages up to at least 1000 V and / or at currents equal to or above 800 A.

11. The busbar current interruption device (20) according to any one of the preceding claims, wherein the configuration of the at least three fuse portions (41, 42, 43, 44) is selected to permanently break an electrical circuit through the busbar member (22) in less than 100 ms; preferably in equal to or less than 60 ms.

12. A battery module (1) comprising a plurality of battery cells (2) connected in series, the battery module (1) further comprising a busbar current interruption device (20) according to any one of the preceding claims, wherein the busbar current interruption device (20) is arranged to electrically connect two adjacent battery cells (2) of the plurality of battery cells (2).

13. The battery module (1) according to claim 12, wherein the busbar current interruption device (20) is configured to permanently break an electrical circuit therethrough in a time shorter than a time that each of the two adjacent battery cells (2), electrically connected by the busbar current interruption device (20), can withstand.

14. A battery pack (50) comprising a plurality of battery modules (1), wherein at least one of the battery modules (1) is a battery module (1) according to any one of claims 12 and 13.

15. A vehicle (100) comprising a battery module (1) according to any one of claims 12 or 13.

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