Connecting element with spring elements

Abstract

Connecting element (10) for electrically connecting battery cells (6) and / or battery modules (8), wherein the connecting element (10) has a connection area (18) for connection to a terminal (12) and a receiving area (22) for detachable connection of a connector (28), wherein at least one spring element (26) is provided for the purpose of establishing an electrically conductive connection with the terminal (12), characterized by the fact that the connection area (18) can be positively connected to the terminal (12), wherein In addition to a locking connection (32), a further spring element (38) is provided for fixing the terminal (12).

Description

State of the art

[0001] The invention relates to a connecting element for electrically connecting battery cells or battery modules, as well as to a battery cell module comprising the connecting element. The invention further relates to a battery having a plurality of battery cells and / or battery modules, each comprising a battery cell, wherein at least two battery cells and / or two battery modules are connected by means of a connecting element.

[0002] Batteries, which have a wide range of applications, for example, in vehicles (e.g., hybrid, plug-in hybrid, and electric vehicles), stationary systems (e.g., wind turbines), and mobile electronic devices (e.g., laptops and communications devices), are subject to very high demands in terms of reliability, service life, and performance. Lithium-ion technology, which is characterized by, among other things, high energy density and extremely low self-discharge, is particularly suitable.

[0003] In order to increase the voltage level or current strength of lithium-ion accumulators or rechargeable lithium-ion batteries, individual accumulator or battery cells are connected in series or parallel to form modules. These modules or battery modules can in turn be combined to form larger sub-units, whereby two or more sub-units ultimately form a complete battery. The individual battery cells are generally connected to form modules using a cell connector, and individual modules are connected using a module connector. In the following, cell or module connectors are generally referred to as connectors or connecting elements. The cell connection is usually a material-to-material connection and is preferably produced using welded connectors, e.g. using laser, ultrasonic, and / or friction welding and similar methods, or riveted connectors.

[0004] An electrically conductive connection between individual modules is often made in a similar way, but primarily through a detachable connection, preferably a screw-on connector. However, the large number of individual components results in a relatively high contact resistance. Corrosion, particularly oxidation, or decreasing contact force, as well as electrochemical voltage potential differences, can further increase the contact resistance over the battery's lifetime. Furthermore, electrical losses increase, initiating heat generation that must be compensated for by increased cooling capacity.

[0005] DE 10 2009 058 953 A1 discloses a module connector that connects individual modules of a battery, comprising multiple battery cells. The module connector is welded to a first module on one side and can be inserted into a socket of another module on the other side.

[0006] From the prior art, for example DE 100 38 650 A1, US 4 778 408 A, EP 1 439 610 A2 and WO 97 / 36344 A1, connectors with spring elements are known which are either simple and inexpensive in design but require a high level of assembly effort, or those which are complex in design but allow comparatively simple and quick fastening.

[0007] Furthermore, the documents WO 2014 / 020 731 A1, US 2012 / 0121 966 A1, JP 2012 - 038 558 A, EP 2 390 945 A1 and KR 10 2014 0 011 664 A are also prior art in this regard. Disclosure of the invention

[0008] According to the invention, a connecting element for electrically connecting two battery cells or battery modules is proposed. The connecting element comprises a connection area for connection to a terminal of a battery cell and / or a battery module and a receiving area for the detachable connection of a connector, wherein at least one spring element is provided to establish an electrically conductive connection to the terminal.

[0009] The connecting element according to the invention provides a detachable connection between battery cells and / or battery modules, offering very low contact resistance at the contact surfaces. Furthermore, a universally applicable connection is available, which can be implemented cost-effectively due to the reduced number of individual parts. Furthermore, positioning errors can be compensated for.

[0010] The connecting element according to the invention is designed such that it can be received on a terminal of a battery cell and / or a battery module. The connecting element comprises a connection region which can be connected to a terminal of a battery cell and / or a battery module in a material-locking, force-locking and / or form-fitting manner. In particular, the connection region is designed such that it can be connected to a terminal of a first battery cell or a first battery module in a material-locking manner by welding, in particular by laser welding. In one embodiment variant according to the invention, the connection region is designed such that the connecting element can be fastened to the terminal by means of a latching element and a latching device or a clip connection. For example, latching lugs, latching hooks or overlaps can be provided on the connecting element, which latch into or engage with correspondingly designed latching devices.overlap them. Furthermore, the locking element can be supplemented by a spring element, which is accommodated in a correspondingly designed recess on the connecting element in such a way that the terminal is secured in addition to the intended clip connection.

[0011] Furthermore, an adapter can be provided on the terminal, particularly in the case of a terminal with a small cross-sectional area, which can be connected to the terminal, for example, by welding, and to which the connecting element according to the invention can be connected in a material, force, and / or form-fitting manner. The adapter can be designed as an intermediate plate.

[0012] The connecting element further comprises a receiving area. The receiving area is designed as a hollow space in which spring elements are provided. In particular, the hollow space, in which a connector, preferably a high-current connector, can be received, has a rectangular shape. The spring elements are preferably arranged such that two spring elements lie opposite one another. Such a spring element is made of a material with good electrical conductivity and is received in a prestressed manner in the receiving area. In particular, such a spring element is designed as a spiral spring, preferably as a leaf spring, with its respective ends being resiliently received in the walls of the receiving area of ​​the connecting element that define the hollow space. Furthermore, the spring elements can be designed as disc springs, disc spring assemblies, or spiral springs in various arrangements.The spring elements provide a spring contact so that a current flows between the terminal of the battery cell and / or the battery module and the connector via the spring elements or the spring contact.

[0013] The connecting element can be provided with a protective device, which is electrically insulating, preferably implemented as a suitable coating, e.g., a coating or lacquer, or a sheath, to eliminate the risk of electric shock for personnel handling the connecting element and provide protection against contact. Furthermore, the risk of short circuits is minimized.

[0014] In a further preferred embodiment, the surfaces of the spring elements that are in contact with the received connector are provided with a coating, preferably with highly conductive materials, such as metallic coatings. The coating permanently ensures low contact and / or transition resistance between the spring elements and the connector under the prevailing conditions, and also prevents or minimizes oxidation and contact corrosion. Preferably, the areas of the connector that are in contact with the at least one spring element are also coated.

[0015] The connector accommodated in the receiving area of ​​the connecting element, e.g., the high-current connector, can be inserted into the receiving area and is secured in this position by the preloaded spring elements. In one embodiment, the inserted connector is secured to a connector section located outside the receiving area by means of additional locking elements to prevent the inserted connector from accidentally slipping out of the receiving area. These locking elements can include locking lugs, locking hooks, projections, or the like.

[0016] Furthermore, further devices can be accommodated on the connecting element, for example sensor devices, e.g. temperature and / or current sensors, and / or voltage detection devices for monitoring the battery cell and / or the battery module.

[0017] According to the invention, at least one battery cell module is provided, which comprises at least two battery cells, in particular lithium-ion battery cells, wherein the terminals of the battery cells or battery modules are electrically conductively connected to one another by means of the connecting element according to the invention. Furthermore, a battery pack is provided, which comprises a plurality of battery cell modules according to the invention.

[0018] Furthermore, the connector is proposed for use in a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), or an electric vehicle (EV). Further applications include e-bikes, stationary storage systems, e.g., solar power systems, and wind turbines. Advantages of the invention

[0019] The solution proposed by the invention for a connecting element for connecting battery cells and / or battery modules enables simple connection of the individual components without the use of special tools and without special assembly and monitoring technology. Thus, the connecting element according to the invention can be used to connect both individual battery cells to each other and individual battery modules to each other. Due to the small component size and correspondingly simple handling and assembly, a battery cell and / or battery module connection can be realized cost-effectively. Another advantage is that the required installation space is minimal.

[0020] The contact resistance at the contact surfaces is very low and can be further improved and protected, especially by suitable coatings.

[0021] Due to the universal detachable connection option provided by the connecting element according to the invention, individual battery cells and / or individual battery modules can be easily dismantled if necessary, for example for maintenance work.

[0022] Furthermore, the connecting element according to the invention can compensate for displacements and / or positioning errors. The connecting element according to the invention permanently reduces and minimizes mechanical and thermal interference factors on the contact resistance. In particular, mechanical and thermal influences on the contact resistance, such as tolerances, vibrations, and thermal expansion, are compensated. The overall system of the battery cell and / or battery module connection becomes less sensitive and thus more robust against external mechanical and thermal stresses.

[0023] An adapter, if arranged between the connecting element and the terminal, allows the connecting element to be arranged independently of the cross-sectional area of ​​the terminal of the battery cell and / or the battery module.

[0024] Furthermore, the protection, in the form of a coating or covering, provides, among other things, contact protection, providing additional protection against electric shocks for maintenance or repair personnel. Consequently, short circuits are prevented and risks to people and the environment are reduced.

[0025] The connecting element according to the invention also offers the possibility of integrating devices for battery cell monitoring, for example a corresponding sensor system, in a simple manner, whereby the required installation space is extremely small. Short description of the drawings

[0026] Further advantages and embodiments of the inventive objects are illustrated by the drawings and explained in more detail in the following description. They show: Fig. 1 a connecting element according to a variant, arranged on a terminal; Fig. 2 shows an embodiment of a connecting element according to the invention. Versions

[0027] From the presentation Fig. 1 shows a connecting element 10 according to the prior art, which is arranged on a terminal 12 of a battery cell 6. The terminal 12 shown protrudes beyond a housing 7 of the battery cell 6. Reference numeral 8 indicates a battery module. An adapter 14 designed as an intermediate plate is arranged on the terminal 12. Fig. 1 shows that the adapter 14 is welded to the terminal 12, indicated by welding zones 16. This material connection can be realized in particular by laser welding, although alternatively a force-fitting and / or form-fitting connection can also be used.

[0028] The connecting element 10 has in the Fig. 1, the embodiment shown has a connection area 18. The connection area 18 is designed to complement the adapter 14 in such a way that the adapter 14 can be fixed thereto in a materially bonded manner, schematically indicated by welding areas 20. The connection of the connecting element 10 or the connection area 18 to the adapter 14 can also be made, for example, via a screw connection. If the terminal 12 is sufficiently large, the connecting element 10 can be connected directly to the terminal 12, for example, in a materially bonded manner, without a corresponding intermediate plate 14.

[0029] The connecting element 10 has a receiving area 22, which is designed as a rectangular cavity 24. At least one spring element 26 is arranged on the receiving area 22 or in the cavity 24 in such a way that it is fixed in the receiving area 22 in a prestressed manner, for example, ends of the spring element 26 are clamped with prestress into the walls of the receiving area 22 that delimit the cavity 24. In the Fig. In the embodiment shown in Figure 1, a connector 28 is inserted between opposing spring elements 26, which connector is fixed by the prestressed spring elements 26 and is in electrically conductive contact with them. The connector 28 is preferably a high-current connector made of an electrically conductive material, for example, a sheet metal or an aluminum and / or copper alloy. The at least one spring element 26 is made of a highly electrically conductive and resilient material, wherein the connector 28 received between the spring elements 26, in particular a high-current connector, is in resilient contact with the spring elements 26. By means of the connector 28 in spring contact, the current of the battery cell 6 and / or the battery module 8 can flow without significant losses.

[0030] The spring elements 26, which are arranged opposite one another in the cavity 24, provide a receptacle for a connector 28, wherein the receptacle can also be designed in the form of a snap closure, wherein barbs or locking elements or the like can be included.

[0031] The connecting element 10 is provided with a coating 30 to protect against accidental contact by personnel handling the connecting element 10. The coating 30 can be implemented as a coating, for example in the form of a paint, powder coating, or foil, which provides insulation on the connecting element 10.

[0032] In Fig. 2 shows a variant embodiment of the connecting element 10 according to the invention.

[0033] Identical elements are identified by identical reference numerals. This embodiment of the connecting element 10 differs in the connection area 18 in that the connecting element 10 is connected to the adapter 14 by means of a locking connection 32. In particular, the connection area 18 is provided with a locking device 34, for example as an edge area overlapping the adapter 14, in which the adapter 14 is positively received. The locking connection 32 can, however, also be designed as a locking element, e.g. as a locking lug and a locking mechanism designed complementarily thereto. In the case of the Fig.2, which is attached to the adapter 14 by means of a type of clip connection, a further spring element 38 is arranged such that a surface 36 of the adapter 14 is in resilient contact with the further spring element 38 and is fixed by it. With sufficient dimensioning of the terminal 12 and a corresponding fastening geometry, the connecting element 10 can be connected directly to the terminal 12 in a form-fitting and / or force-fitting manner without the use of the adapter 14.

[0034] By means of the connecting element 10 according to the invention, individual battery cells 6 can be connected to one another to form the battery module 8. In particular, battery cells 6 and / or battery modules 8 connected in this way are used in hybrid vehicles (HEVs), plug-in hybrid vehicles, or electric vehicles (EVs), as well as in e-bikes and stationary energy storage systems, such as solar systems and wind turbines.

[0035] The connecting element 10 according to the invention can be manufactured as an injection-molded component from an electrically insulating material or from an extruded or drawn profile, wherein the spring elements 26 can be injected or subsequently introduced. It is possible for the spring elements 26 and possibly 38 to be overmolded, for example, with a plastic and connected as a semi-finished product to the connecting element 10, as a sheet metal part or extruded part made of metal, in particular by gluing, locking, clipping, etc. However, the spring elements 26, possibly 38, and the connecting element 10 can also be completely overmolded with a plastic, so that no further connection processes are necessary.

[0036] The invention is not limited to the embodiments described here and the aspects highlighted therein. Rather, numerous modifications are possible within the scope of the claims, which are within the scope of one skilled in the art.

Claims

[1] Connecting element (10) for electrically connecting battery cells (6) and / or battery modules (8), wherein the connecting element (10) has a connection area (18) for connection to a terminal (12) and a receiving area (22) for the detachable connection of a connector (28), wherein at least one spring element (26) is provided for the purpose of establishing an electrically conductive connection with the terminal (12), characterized by , that the connection area (18) can be positively connected to the terminal (12), wherein in addition to a locking connection (32), a further spring element (38) is provided for fixing the terminal (12). [2] Connecting element (10) according to claim 1, characterized by that an adapter (14) is arranged on the terminal (12) and can be connected to the connection area (18). [3] Connecting element (10) according to claim 1 or 2, characterized bythat the connection area (18) is designed such that it can be connected to the terminal (12) in a materially bonded manner. [4] Connecting element (10) according to one of the preceding claims, characterized by that the at least one spring element (26) is pre-tensioned and arranged in the receiving area (22) designed as a cavity in such a way that the connector (28) can be inserted between two opposite spring elements (26) and is in resilient contact with the at least one spring element (26). [5] Connecting element (10) according to one of the preceding claims, characterized by that the at least one spring element (26) is made of an electrically conductive material. [6] Connecting element (10) according to one of the preceding claims, characterized bythat the connector (28) and the at least one spring element (26) in contact with it are at least partially provided with a coating to reduce contact resistance. [7] Connecting element (10) according to one of the preceding claims, characterized by that the connecting element (10) is at least partially provided with a coating (30) which forms an insulation. [8] Connecting element (10) according to one of the preceding claims, characterized by that locking elements are provided on the connector (28) which prevent the inserted connector (28) from slipping out of the receiving area (22). [9] Connecting element (10) according to one of the preceding claims, characterized by that sensor devices and / or voltage detection devices for monitoring the battery cell (6) and / or the battery module (8) are integrated therein. [10] Battery module (8) with at least two battery cells (6) with connecting elements (10) according to one of claims 1 to 9, with which terminals (12) of the battery cells (6) are electrically connected to one another. [11] Battery pack comprising a plurality of battery modules (8) according to claim 10. [12] Use of the connecting element (10) according to one of claims 1 to 9 in a hybrid vehicle (HEV), in a plug-in hybrid vehicle (PHEV), in an electric vehicle (EV), in e-bikes, in stationary solar and / or wind power plants.

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