Cell connectors for an electrical energy storage system

Abstract

A cell connector for an electrical energy storage device is described, wherein the cell connector is configured to electrically connect different storage cells of the energy storage device. The cell connector is made of a composite material comprising at least two different material layers.

Description

[0001] The invention relates to a cell connector for an electrical energy storage device.

[0002] A vehicle that is at least partially electrically powered has an energy storage device for storing electrical energy to operate the vehicle's electric drive motor. The energy storage device typically comprises a plurality of individual storage cells, in particular a plurality of cylindrical cells, arranged in a housing of the energy storage device. The energy storage device may further comprise a cell contacting system with a plurality of cell connectors, wherein the cell contacting system is configured to electrically connect the individual storage cells to one another according to a specific electrical wiring configuration (e.g., a 3P, a 4P, or a 5P configuration).

[0003] The cell contacting system, in particular the multitude of cell connectors of the cell contacting system, are subject to mechanical stresses during the operation of the vehicle.

[0004] This document addresses the technical challenge of providing a particularly robust cell connector for a cell contacting system of an electrical energy storage device.

[0005] The problem is solved by the independent claim. Advantageous embodiments are described, inter alia, in the dependent claims. It should be noted that additional features of a claim dependent on an independent claim, without the features of the independent claim itself or only in combination with a subset of the features of the independent claim, can constitute a separate invention independent of the combination of all features of the independent claim, which can be made the subject of an independent claim, a divisional application, or a subsequent application. This applies equally to technical teachings described in the description, which can constitute an invention independent of the features of the independent claims.

[0006] According to one aspect, a cell connector for an electrical energy storage device is described, where the energy storage device typically comprises a multitude of storage cells. The cell connector is designed to electrically connect different storage cells of the energy storage device to one another.

[0007] The cell connector is made of a composite material comprising at least two different material layers. The cell connector can, in particular, be manufactured from a sheet of the composite material, especially by stamping. In a preferred example, the cell connector consists entirely of the composite material.

[0008] The cell connector typically has a first contact area for contacting a first memory cell and a second contact area for contacting a second memory cell, which are electrically connected to each other via a connecting bridge of the cell connector. The first contact area, the connecting bridge, and the second contact area can each be made of the composite material, or in particular, each consist of the composite material.

[0009] The composite material can comprise a first material layer and a second material layer. The at least two material layers of the composite material can be clad, in particular roll-clad, to form the composite material. The first material layer can comprise pure aluminum. In particular, the first material layer can consist of pure aluminum.

[0010] The second material layer can consist of a material that has a higher stiffness and / or strength than pure aluminum. Alternatively or additionally, the second material layer can comprise (or consist of) an aluminum alloy.

[0011] This describes a cell connector consisting of a composite material with multiple layers of different materials. This allows for the creation of a particularly stable and robust cell connector.

[0012] The cell connector can have a fusible link (on the connecting bridge), which is preferably also made of the composite material.

[0013] The (sheet-shaped) composite material can have a specific overall thickness, and the first layer of material (made of pure aluminum) can have a first thickness. The first thickness is preferably 50% or more, or 60% or more, and particularly 80% or more, of the total thickness. This allows for the provision of a particularly efficient and stable cell connector.

[0014] According to another aspect, a cell connection system for an electrical energy storage device is described, wherein the energy storage device comprises a plurality of storage cells. The cell connection system comprises a plurality of cell connectors, each configured as described in this document.

[0015] According to another aspect, an electrical energy storage device for a motor vehicle is described. The energy storage device comprises a multitude of storage cells and a cell contacting system, configured as described in this document.

[0016] According to another aspect, a (road) motor vehicle (in particular a passenger car or a truck or a bus or a motorcycle) is described that includes the energy storage device described in this document.

[0017] It should be noted that the devices and systems described in this document can be used both alone and in combination with other devices and systems described in this document. Furthermore, any aspect of the devices and systems described in this document can be combined with one another in a variety of ways. In particular, the features of the claims can be combined with one another in a variety of ways. Features listed in parentheses are to be understood as optional features.

[0018] The invention will now be described in more detail using exemplary embodiments. Fig. 1 an exemplary vehicle with an energy storage system for storing electrical energy; Fig. 2a an example of a round cell; Fig. 2b an exemplary contacting system for an energy storage device; Fig. 2c an exemplary contacting system for a 4P connection; Fig. 3a an exemplary cell connector; and Fig. 3b different layers of a cell connector.

[0019] As stated at the outset, this document deals with providing a particularly robust cell connector for the cell contacting system of an electrical energy storage device. In this context, it shows Fig. 1 an exemplary vehicle 100 with an electrical energy storage device 110 for storing electrical energy and with an electric drive motor 102, which is operated with electrical energy from the energy storage device 110.

[0020] The Energy Storage 110 comprises a variety of storage cells, especially cylindrical cells. Fig. Figure 2a shows an exemplary storage cell 200, in particular a cylindrical cell, for an electrical energy storage device 110. The storage cell 200 has a circular cylindrical shape. A negative contact point 201 and a positive contact point 202 for electrical connection of the storage cell 200 are arranged on an end face of the storage cell 200. The negative contact point 201 can be formed by the end face of the cylindrical storage cell 200. The end face of the storage cell 200 can be arranged on the end face of a (circular cylindrical) housing side wall 206 of the storage cell 200. The positive contact point 202 can be formed by a bolt that protrudes from the end face of the storage cell 200. In another example, the polarity of the contact points 201 and 202 can be exactly reversed.

[0021] The electrical energy storage device 110 typically comprises a large number of storage cells 200. The storage cells 200 can be, as exemplified in Fig. As shown in Figure 2b, the cell contacting system 216 connects the cells in a specific electrical arrangement. The energy storage device 110 can, for example, have Z storage cells 200, which are subdivided into subgroups of M storage cells 200 each. The M storage cells 200 of a subgroup can be electrically connected in parallel to each other by a (partial) contacting system 220 of the cell contacting system 216. The storage cell arrangement 210 then has a so-called MP (e.g., 3P for M=3, 4P for M=4, or 5P for M=5) arrangement.

[0022] Fig. Figure 2b shows an exemplary section of a cell contacting system 216, in which two (partial) contacting systems 220 are depicted, each configured to connect a subgroup 240 of M=5 memory cells 200 in parallel. The individual contacting systems 220 are further configured to connect two different subgroups 240 in series.

[0023] A (partial) contacting system 220 comprises M connecting bridges 230, each configured (in pairs) to electrically connect the first contact point 201 of a memory cell 200 from a first subgroup 240 to the second contact point 202 of a memory cell 200 from a second subgroup 240 (so that the first and second subgroups 240 are connected in series). Furthermore, a (partial) contacting system 220 may optionally have (M-1) connecting bridges 221, each configured to connect two memory cells 200 from the same subgroup 240 in parallel.

[0024] Fig. Figure 2c shows an exemplary (partial) contact system 220 for an MP arrangement, with M=4. The (partial) contact system 220 is made of a metal sheet (in particular, stamped). The connecting bridges 230 for the serial connection of two memory cells 200 from different subgroups 240 have at one end a first contact area (or a first contact element) 231 (for connection with the first contact point 201 of one memory cell 200) and at the opposite end a second contact area (or a second contact element) 232 (for connection with the second contact point 202 of the other memory cell 200).

[0025] The combination of a first contact area 231, a connecting bridge 230, and a second contact area 232 can be called a cell connector. A cell connector can (as part of the connecting bridge) include a fuse designed to melt in the event of excessive current. Fig. Figure 3a shows an example of a cell connector 350 with a fuse 310.

[0026] During operation, the individual cell connectors 350 of the cell contacting system 216 of the energy storage device 110 of a vehicle 100 are typically subjected to relatively high mechanical loads, which can lead to impairment of the energy storage device 110. In the Fig. 3a and Fig. Figure 3b shows a cell connector 350 consisting of a ribbon-shaped composite material 300 extending from the first contact area 231, via the locking device 310, to the second contact area 232. The ribbon-shaped composite material 300 has several different material layers 301, 302, each consisting of a different material. The use of multiple material layers 301, 302 makes it possible to provide a particularly robust cell connector 350.

[0027] In a preferred example, the composite material 300 has a first material layer 301 made of (pure) aluminum to provide high electrical conductivity. A second material layer 302 can comprise an aluminum alloy, in particular AlMg3, to increase the strength of the (sheet-shaped) composite material 300.

[0028] Technical aluminum alloys (such as Al-Mg, Al-Si, Al-Cu) typically have a lower melting range than pure aluminum due to their composition. To utilize this lower melting range, pure aluminum sheets can be roll-clad with an alloy, so that, for example, 90% of the sheet thickness consists of Al-99.5 and 10% of AlMg3. The cell connectors 350 constructed from this composite 300 combine the following advantages: • Current flow through the pure aluminum portion, • Increased mechanical strength due to the higher-strength Al alloy (e.g. AlMg3), and / or • Earlier tripping of the fuse due to the lower melting point of the Al-X alloy, leading to an increase in the electrical intrinsic protection.

[0029] The present invention is not limited to the embodiments shown. In particular, it should be noted that the description and the figures are intended only to illustrate the principle of the proposed devices and systems by way of example.

Claims

[1] Cell connector (350) for an electrical energy storage device (110); wherein - the cell connector (350) is set up to electrically connect different storage cells (200) of the energy storage device (110) to each other; and - the cell connector (350) is made of a composite material (300) which has at least two different material layers (301, 302). [2] Cell connector (350) according to claim 1, wherein - the cell connector (350) has a first contact area (231) for contacting a first memory cell (200) and a second contact area (232) for contacting a second memory cell (200), which are electrically connected to each other via a connecting bridge (230) of the cell connector (350); and - the first contact area (231), the connecting bridge (230) and the second contact area (231) are made of the composite material (300), in particular consist of. [3] Cell connector (350) according to one of the preceding claims, wherein the cell connector (350) consists entirely of the composite material (300). [4] Cell connector (350) according to one of the preceding claims, wherein the cell connector (350) is made from a sheet consisting of the composite material (300), in particular by stamping. [5] Cell connector (350) according to any one of the preceding claims, wherein the composite material (300) comprises, - a first layer of material (301) made of pure aluminum; and - a second layer of material (302) made of a material that has a higher stiffness and / or strength than pure aluminum. [6] Cell connector (350) according to claim 5, wherein the second material layer (302) comprises an aluminum alloy. [7] Cell connector (350) according to one of claims 5 to 6, wherein - the composite material (300) has a total thickness; - the first material layer (301) has a first thickness; and - the first thickness is 50% or more of the total thickness. [8] Cell connector (350) according to one of the preceding claims, wherein the at least two material layers (301, 302) of the composite material (300) are clad, in particular roll clad. [9] Cell connection system (216) for an electrical energy storage device (110) comprising a plurality of storage cells (200); wherein the cell connection system (216) comprises a plurality of cell connectors (350) according to any one of the preceding claims. [10] Electrical energy storage device (110) for a motor vehicle (100), comprising, - a large number of memory cells (200); and - a cell contacting system (216) according to claim 9.

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