Connecting device for electrically connecting at least two energy storage elements for storing electrical energy

Abstract

Connecting device for electrically connecting at least one first energy storage element (10) for storing electrical energy to at least one second energy storage element (12) for storing electrical energy, in particular for a vehicle, with at least one electrically conductive contact element (14) which can be electrically connected to respective contacts of the energy storage elements (10, 12), via which contact element the contacts of the energy storage elements (10, 12) can be electrically connected to one another, comprising: - at least one screw element (20) which can be inserted through a corresponding through-opening (18) of the flexible contact element (14) for clamping the flexible contact element (14) against one of the contacts; - at least one pressure plate (32), by means of which the screw element (20) can be supported on the contact element (14); and - a housing which has at least one lower shell (34) which at least partially covers the contact element (14) and the pressure plate (32) on both sides, characterized in that the housing has at least one upper shell (36) which at least partially covers a respective upper side (40, 42) of the contact element (14) and the pressure plate (32) facing away from the lower shell (34), and which has a further through-opening (50) for the screw element (20).

Description

[0001] The invention relates to a connecting device for electrically connecting at least two energy storage elements for storing electrical energy, in particular of a vehicle, according to the preamble of patent claim 1.

[0002] Such a connecting device for electrically connecting at least one first energy storage element for storing electrical energy to at least one second energy storage element for storing electrical energy, in particular for a vehicle, is already sufficiently known from the general prior art and in particular from series vehicle construction. In vehicles such as electric vehicles and hybrid vehicles, energy storage devices are used by means of which electrical energy or electrical current is stored. Such an energy storage device is, for example, a battery which, due to its operating voltage, which is greater than 60 volts, is usually designed as a high-voltage battery (HV battery). Such a battery serves to store electrical energy with which at least one electric motor can be supplied to drive the vehicle.

[0003] Such a battery typically comprises a plurality of battery modules, also referred to as modules. Such a battery module is an energy storage element for storing electrical energy. The respective battery module can comprise a plurality of further energy storage elements in the form of battery cells for storing electrical energy. The battery cells are electrically connected to one another, in particular via respective electrical contacts, and are connected in series, for example. The respective battery modules, in turn, are also electrically connected to one another, in particular via respective electrical contacts, and are thus interconnected. In order to ensure an electrical current flow, both the battery cells in the modules and the modules themselves are electrically connected to one another.

[0004] For this purpose, the connecting device comprises at least one electrically conductive contact element, which can be electrically connected to the respective contacts of the respective energy storage elements. Thus, the contacts of the energy storage elements can be electrically connected to one another via the contact element.

[0005] DE 696 00 849 T2 discloses a design of a cell pack in which a lower shell is provided for fixing the cells.

[0006] US 2011 / 0 104 555 A1 discloses an arrangement in which cylindrical cells are secured by a holder. The connecting element is designed for the electrical connection of the cells and is protected from unwanted contact by an insulating sleeve.

[0007] Furthermore, JP 09266025 A discloses a connector for charging a capacitor of an electric vehicle and EP 0 524 377 A1 discloses an accumulator battery whose cells are electrically connected on the top side of the housing by cell connectors attached to the cell poles.

[0008] Connecting the energy storage elements of a battery, particularly a high-voltage battery, and in particular disconnecting this connection, for example during maintenance or repair, is usually very difficult to carry out because the high operating voltage poses a potential hazard to the person carrying out the repair or maintenance. A high-voltage battery usually weighs between 400 and 500 kilograms, making transporting such a battery complex and costly. In order to safely service or repair such a battery, the entire battery is usually removed from the vehicle in a workshop and then opened and repaired by specialist personnel at a factory. For safety reasons, only trained personnel are permitted to work on such a battery.

[0009] It is therefore desirable to implement a simple and safe separation of the energy storage elements and thus of a high-voltage current path, especially at the module level, so that the battery can be serviced or repaired in the workshop, for example, rather than requiring complex and costly transport. Typically, each battery module has an operating voltage of less than 60 volts, making it easy to handle.

[0010] The object of the present invention is therefore to provide a connecting device of the type mentioned at the outset, by means of which a simple, cost-effective and safe maintenance or repair of the energy storage elements can be realized.

[0011] This object is achieved according to the invention by a connecting device having the features of patent claim 1. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims.

[0012] In order to further develop a connecting device of the type specified in the preamble of patent claim 1 in such a way that a particularly simple, cost-effective, and safe repair or maintenance of the energy storage elements can be realized, the invention provides at least one screw element for clamping the flexible contact element against one of the contacts of the energy storage elements. Furthermore, the invention provides for the contact element to be flexible. This allows, for example, production-related positional tolerances of the contacts of the energy storage elements to be compensated for, since the contact element can be deformed, in particular bent, in particular manually, and thus adapted to the positional tolerances.Furthermore, the invention provides that the flexible contact element has at least one through-hole corresponding to the screw element, through which the screw element can be inserted. This makes it possible to clamp the contact element particularly tightly against one contact by means of the screw element. Furthermore, it is possible to detach the contact element from the corresponding contact in a particularly simple manner by loosening the screw element.

[0013] According to the invention, the connecting device further comprises at least one pressure plate, by means of which the screw element can be supported on the contact element. In other words, the screw element is screwed into a corresponding thread, whereby the pressure plate arranged between the screw element and the contact element is clamped against the contact element by means of the screw element. As a result, the contact element is clamped against the corresponding contact via the pressure plate by means of the screw element and thus electrically contacted with it. The use of the pressure plate can ensure that electrical current flows via the respective contact surfaces of the contact and the contact element and not via the respective threads of the energy storage element and the screw element or the screw element itself.

[0014] Furthermore, the connecting device according to the invention comprises a housing which has at least one lower shell at least partially covering the contact element and the pressure plate on both sides, and at least one upper shell at least partially covering a respective upper side of the contact element and the pressure plate facing away from the lower shell. The upper shell has a further through-opening for the screw element. This makes it possible to protect the screw element, the contact element and the pressure plate from unwanted contact. In other words, the housing can provide contact protection, so that the risk of a person connecting the energy storage elements by means of the connecting device or breaking the connection between the energy storage elements coming into contact with the pressure plate, the contact element or the screw element can be kept particularly low.This makes it possible to electrically connect the energy storage elements by means of the connecting device according to the invention in a particularly simple and safe manner and to release such an electrical connection, so that, for example, the energy storage elements can be serviced or repaired without having to transport the energy storage elements or a battery comprising the energy storage elements, in particular a high-voltage battery, in a time-consuming and costly manner.

[0015] Further advantages, features, and details of the invention will become apparent from the following description of a preferred embodiment and from the drawings. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respective combinations specified, but also in other combinations or on their own, without departing from the scope of the invention.

[0016] The drawing shows in: Fig. 1 a schematic and perspective top view of a connecting device according to a first embodiment, by means of which at least two energy storage elements for storing electrical energy are electrically connected to one another, wherein the connecting device comprises at least one flexible contact element, at least one screw element, at least one pressure plate and at least one housing; Fig. 2 a schematic and perspective sectional view of the connecting device according to Fig. 1; Fig. 3 shows a further schematic sectional view of the connecting device according to the first embodiment; Fig. 4 is a schematic perspective view of the connecting device according to the first embodiment; and Fig. 5 a schematic and perspective sectional view of the connecting device according to a second embodiment,

[0017] In the figures, identical or functionally identical elements are provided with the same reference symbols.

[0018] Fig. 1 shows a schematic and perspective top view of a connecting device according to a first embodiment for electrically connecting at least one in Fig. 1 partially recognizable first energy storage element 10 with at least one in Fig. 1 also shows a second energy storage element 12, which is also partially visible. The energy storage elements 10 and 12 are used, for example, in a vehicle and serve to store electrical energy or electrical current, wherein the vehicle is designed, for example, as a hybrid vehicle or electric vehicle. The vehicle thus comprises at least one electrical machine, which can be operated, for example, as an electric motor in engine mode. The vehicle can be driven by the electrical machine in its engine mode, so that the electrical machine is a traction machine.

[0019] The energy storage elements 10 and 12 are, for example, respective modules, which are also referred to as battery modules. The respective energy storage element 10 or 12 comprises, for example, a plurality of individual cells or battery cells, each of which serves to store electrical energy. The respective individual cells are electrically connected or interconnected, in particular via respective electrical contacts, wherein the respective individual cell has an operating voltage of a few volts. By electrically interconnecting the individual cells, the respective battery module (energy storage element 10 or 12) has an operating voltage which is significantly higher than the respective electrical voltage of the individual battery cells. For example, the respective battery module has an operating voltage of more than 50 volts but less than 60 volts.

[0020] The respective module (energy storage element 10 or 12) in turn has at least one Fig. 1, so that the energy storage elements 10 and 12 can be electrically connected to one another via their respective electrical contacts. For this purpose, the connecting device is electrically connected to the respective contact elements of the energy storage elements 10 and 12, so that the contacts of the energy storage elements 10 and 12 are electrically connected to one another via the connecting device. Through this electrical connection of the energy storage elements 10 and 12, they can be electrically interconnected. The energy storage elements 10 and 12 are, for example, components of an energy storage device in the form of a battery for storing electrical current. By interconnecting the modules (energy storage elements 10 and 12) as described, an operating voltage of the battery can be achieved which is significantly greater than 60 volts.

[0021] The electric motor can be supplied with electrical current or electrical energy from the battery during motor operation, thus serving as a traction battery. Since the battery's operating voltage is significantly higher than 60 volts, the battery is designed as a high-voltage battery (HV battery).

[0022] In order to realize a particularly secure, simple, and cost-effective connection of the energy storage elements 10 and 12 as well as a simple, secure, and cost-effective separation of this connection between the energy storage elements 10 and 12, the connecting device comprises at least one electrically conductive flexible contact element 14 that can be electrically connected to the respective contacts of the energy storage elements 10 and 12 or—in the finished state of the vehicle—is connected, via which the contacts of the energy storage elements 10 and 12 can be electrically connected to one another or are connected. The energy storage elements 10 and 12 are also referred to as a cell block, wherein the contact element 14 can ensure an electrical current flow from cell block to cell block. The contact element 14 is formed, for example, from a metallic material and can have exactly one layer.Alternatively, it is conceivable for the contact element 14 to be formed by a layering of several parts, in particular sheets, stacked on top of one another. Preferably, the contact element 14 is formed as a flexible strip, in particular made of copper. Alternatively, it is conceivable for the contact element 14 to be formed by a layering of several copper sheets stacked on top of one another. This is particularly well-suited to use in conjunction with . Fig. 2 it can be seen that the contact element 14, which in the present case is designed as a flexible copper strip (Cu strip), is pressed and perforated at its ends 16 so that it has a through opening 18 at each of its ends.

[0023] The contact element 14 is flexible and can thus be deformed, in particular bent, manually, for example by a person who connects the energy storage elements 10 and 12 or releases this connection, so that, for example, production-related positional tolerances of the energy storage elements 10 and 12 and thus of their contacts can be compensated or equalized.

[0024] The connecting device further comprises screw elements in the form of screws, of which Fig. 1 to 4 a screw marked 20 can be seen. The other of the screws is in Fig. 1 to 4 are not shown for clarity. By means of the screw 20, the contact element 14 is clamped against the corresponding contact of the energy storage element 12. By means of the Fig. 1 to 4, the contact element 14 is clamped against the contact of the energy storage element 10. In other words, the contact element 14, which represents a connector element, is firmly clamped to a respective contact point of the respective inch block by means of the respective screw. Fig. 3 shows that the screw 20 has a shaft 22 and a screw head 24 connected to the shaft 22 and, for example, formed integrally with the shaft 22, with a collar 26. The screw 20 is at least indirectly supported on the contact element 14 via the collar 26, so that the contact element 14 is clamped against the corresponding contact by means of the collar 26.

[0025] Out of Fig. 2 that the respective cell block (energy storage element 10 or 12) has a thread, which in this case is formed by a respective threaded bushing 28. The thread of the respective threaded bushing 28 is an internal thread, with the shaft 22 of the screw 20 having an external thread 30 corresponding to the internal thread. If the screw 20 is screwed into the corresponding internal thread of the threaded bushing 28 via its external thread 30, a clamping force is exerted on the contact element 14 - since the screw 20 is supported at least indirectly on the contact element 14 via its collar 26 - and the contact element 14 is clamped against the corresponding contact by means of this clamping force. This means that the clamping force is transmitted to the contact element 14 via the collar 26 on the screw head 24. Since the threaded bushing 28 is fixed to the respective cell block, the internal thread is fixed to the respective cell block.

[0026] The connecting device further comprises—in particular for each screw—a pressure plate 32, which in this case is electrically insulating. For example, the pressure plate 32 is made of a plastic. The screw 20 can be supported or is supported on the contact element 14 via the pressure plate. For this purpose, the pressure plate 32 is arranged between the contact element 14, in particular its end 16, and the collar 26 or the screw head 24, so that the aforementioned clamping force is transmitted via the collar 26 to the pressure plate 32 and, via this, finally to the contact element 14. The clamping force is transmitted via the contact element 14 to respective contact surfaces of the contact element 14 and the corresponding contact of the cell block, so that the contact surfaces are pressed firmly against one another. This means that the contact surfaces touch one another, so that electrical current can flow across the contact surfaces.Thus, the electric current flows via the contact surfaces and not via the external thread 30 or the screw 20 as a whole.

[0027] From a summary of Fig. 2 with Fig. 4 it can be seen that the connecting device comprises a housing which has a particularly well Fig. 4 recognizable lower shell 34 and a section of Fig. 2 has an upper shell 36 which can be connected or is connected to the lower shell 34.

[0028] The lower shell 34 covers the contact element 14 and the pressure plate 32 on both sides, at least partially and in this case at least predominantly, with a partial area of ​​the contact element 14 also being covered downwards towards the energy storage element 12. This means that the lower shell 34 is arranged on both sides of the contact element 14 and the pressure plate 32, as well as on an underside 38 of the contact element 14 facing away from the screw head 24. The upper shell 36 at least partially and preferably at least predominantly or completely covers an upper side 40 or 42 of the contact element 14 or the pressure plate 32 facing away from the lower shell 34 or the energy storage element 12. This allows the risk of the aforementioned person touching the contact element 14, the screw 20, or the pressure plate 32 to be kept particularly low.Preferably, the upper shell 36 and the lower shell 34 are electrically insulating. It may be provided that the lower shell 34 and the upper shell 36 are made of a plastic.

[0029] Looks particularly good Fig. 3 that the through-opening 18 of the contact element 14 has an inner circumference, in particular an inner diameter, which is larger than an outer circumference, in particular an outer diameter, of a length portion of the screw 20, in particular of the shaft 22, arranged in the through-opening 18 or penetrating the through-opening 18. This makes it possible to move the contact element 14 in the radial direction of the shaft 22 relative to the latter, while the shaft 22 penetrates the corresponding through-opening 18. This makes it possible to compensate for positional tolerances of the energy storage elements 10 and 12, in particular of their contacts, since the contact element 14 can be displaced accordingly and thus moved into a position relative to the energy storage elements 10 and 12 and secured in this position by means of the screw 20 on the corresponding cell block (energy storage element 12).This allows for assembly tolerance compensation between the cell blocks. The screw 20 acts as a clamping screw, which is fixed to the corresponding cell block via the corresponding threaded bushing 28. The through-hole 18 on the contact element 14 assumes a travel tolerance, allowing positional tolerances to be compensated.

[0030] The clamping force acting as a contact force between the respective components is created via the screw 20 and the pressure plate 32, which is centered to the screw 20, in particular the shaft 22, via its through-hole 42. In other words, the pressure plate 32 has a particularly well-designed Fig. 3 has a through opening 42 through which the screw 20, in particular the shaft 22, is inserted.

[0031] In this case, the screw 20 functioning as a clamping screw is constructed in two parts. The clamping screw (screw 20) comprises a base body, designated as a whole by 44, which is also referred to as the threaded body. The base body 44 is formed, for example, from a metallic material. The shaft 22 and the screw head 24 and thus the collar 26 are formed by the base body 44. The clamping force is transmitted via the base body 44. The screw 20 also comprises a plastic 46 with which the screw head 24 is provided. The plastic 46 is an electrically insulating plastic. In this case, the screw head 24 is overmolded with the plastic 46. The plastic 46 forms a tool engagement point 48, via which a screwing tool can interact in a form-fitting manner to tighten and loosen the screw 20.In other words, it is possible to transmit torques from the screwing tool via the plastic 46 or the tool engagement point 48 to the screw 20. The plastic 46 is connected, in particular in a form-fitting and / or force-fitting manner, to the base body 44, in particular to the screw head 24, in a rotationally fixed manner, so that the torques transmitted from the screwing tool via the tool engagement point 48 to the plastic 46 can be transmitted from the plastic 46 to the base body 44 and thus to the screw 20 as a whole.

[0032] In this case, the tool engagement point 48 is an outer peripheral tool engagement point and is designed, for example, as a polygon, in particular as an external polygon. For example, the tool engagement point 48 is designed, in this case, as an external hexagon.

[0033] For the rotationally fixed connection of the plastic 46 to the screw head 24, the screw head 24 has, for example, a second tool engagement point, which can be designed as an outer peripheral tool engagement point, such as an external polygon, in particular an external hexagon. The plastic 46 has a third tool engagement point, which corresponds to the tool engagement point of the screw head 24. The further tool engagement point of the plastic 46 is thus, for example, an inner peripheral tool engagement point, in particular an internal polygon, such as an internal hexagon. The torques transmitted to the plastic 46 can thus be transmitted to the base body 44 via the further tool engagement point of the plastic 46 and the tool engagement point of the screw head 24. The plastic 46 is preferably a robust plastic, so that even high torques can be transmitted to the screw 20 without damage.

[0034] The screwing tool comprises, for example, a socket having a tool engagement portion, in particular a polygon socket, corresponding to the tool engagement portion 48. The plastic 46 insulates the screwing tool, in particular the socket, and transmits the torque. To prevent the plastic 46 from detaching from the base body 44, it is preferably provided that the plastic 46 is back-injected onto the screw head 24.

[0035] The housing, i.e., the lower shell 34 and the upper shell 36, can provide protection against contact, so that in particular the contact element 14, the pressure plate 32, and the screw 20 can be protected from unwanted contact by the person. The housing functions, in particular, as an insulating housing. Fig. 2 shows that the upper shell 36 has respective through-openings 50 for the respective screws. Using the example of the screw 20, it can be seen that at least a length of the screw 20 penetrates the corresponding through-opening 50 of the contact element 14. The through-opening 50 allows the screw 20 to be fastened. Preferably, the through-opening 50 is dimensioned in its inner circumference, in particular its inner diameter, such that the aforementioned positional tolerances can be compensated.

[0036] The dimensions of the upper shell 36 and the plastic 46, i.e., a plastic cap of the screw 20 formed by the plastic 46, are preferably coordinated to ensure electrical contact safety. For example, the respective surfaces of the plastic cap and the upper shell 36 overlap. To facilitate handling, ribs and / or eyelets could be provided on the sides of the housing for secure mounting. Overall, Fig. 1 to 4 it can be seen that the connecting device provides a simple and cost-effective solution for safely separating the electrical connection between the cell blocks and thus a high-voltage current path.

[0037] Fig. Figure 5 shows a second embodiment of the connecting device. In the second embodiment, as can be seen particularly well from a summary of Fig. 3 and Fig. 5, the upper shell 36 has a guide collar 52 for each through-hole 18 and thus for each screw 20, through which the respective screw 20 can be inserted. During this insertion, the respective screw 20 is guided by means of the guide collar 52, since the screw 20 can come into radial support with the respective guide collar 52. This allows for particularly simple assembly.

[0038] The respective guide collar 52 is dimensioned in such a way that the plastic 46 with the tool attack 48 also finds space in the respective guide collar 52 and that the tool attack 48 can interact with the screwing tool.

Claims

[1] Connecting device for electrically connecting at least one first energy storage element (10) for storing electrical energy to at least one second energy storage element (12) for storing electrical energy, in particular for a vehicle, with at least one electrically conductive contact element (14) which can be electrically connected to respective contacts of the energy storage elements (10, 12), via which contact element the contacts of the energy storage elements (10, 12) can be electrically connected to one another, comprising: - at least one screw element (20) which can be inserted through a corresponding through-opening (18) of the flexible contact element (14) for clamping the flexible contact element (14) against one of the contacts; - at least one pressure plate (32), by means of which the screw element (20) can be supported on the contact element (14); and - a housing which has at least one lower shell (34) which at least partially covers the contact element (14) and the pressure plate (32) on both sides, characterized by that the housing has at least one upper shell (36) which at least partially covers a respective upper side (40, 42) of the contact element (14) and the pressure plate (32) facing away from the lower shell (34), which upper shell has a further through-opening (50) for the screw element (20). [2] Connecting device according to claim 1, characterized by that the pressure plate (32) is electrically insulating. [3] Connecting device according to claim 1 or 2, characterized by that the upper shell (36) and lower shell (34) are each electrically insulating. [4] Connecting device according to one of the preceding claims, characterized bythat the screw element (20) has a screw head (24) via which the screw element (20) can be supported on the pressure plate (32), wherein the screw head (24) is provided with an electrically insulating plastic (46). [5] Connecting device according to one of the preceding claims, characterized by that the through-opening (18) of the contact element (14) has an inner circumference, in particular an inner diameter, which is larger than an outer circumference, in particular an outer diameter, of a length region of the screw element (20) accommodated in the through-opening (18). [6] Connection arrangement of a first energy storage element (10) for storing electrical energy to a second energy storage element (12) for storing electrical energy, in particular for a vehicle, in which the energy storage elements (10, 12) are electrically connected to one another by means of at least one connection device according to one of the preceding claims.

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