DE102021131308A1 - Cell contacting system and method for manufacturing a cell contacting system - Google Patents

Abstract

The present invention relates to a cell contacting system (100) for an electrochemical device (200) which has a plurality of electrochemical cells, the cell contacting system (100) having the following: a large number of cell connectors (110) for the electrically conductive connection of a large number of electrochemical cells ( 210); a plurality of bonding wires for contacting the cell connectors for voltage tapping of the electrochemical cells (210); a holding device (130) made of a three-dimensional one-piece plastic film molding for holding the plurality of cell connectors (110) and the plurality of contacting wires (120). The invention also relates to a method for producing a cell contacting system (100).

Description

The present invention relates to a cell contacting system for an electrochemical device that has a plurality of electrochemical cells. Furthermore, the invention relates to a method for producing a cell contacting system.

STATE OF THE ART

Cell contacting systems for electrochemical devices are well known in the prior art. Such cell contacting systems are used to allow a power current to flow by connecting a plurality of electrochemical cells. To this end, cell contacting systems have a large number of cell connectors. In addition, cell contacting systems typically include a contacting device to enable measurement and monitoring of physical variables, such as voltage and temperature, of the electrochemical device. Such contacting devices are usually used in the form of FPC (Flexible Printed Circuits). In order to measure the cell voltage of an electrochemical cell, a contacting pad for voltage tapping is arranged on the cell. For arranging and fixing the cell connectors and the contacting device on the electrochemical device, a holding device which is produced by means of injection molding is usually used.

The conventional cell contacting systems are expensive to manufacture due to their structure described above. In addition, the known cell contacting systems are not sufficiently suitable for use in larger electrochemical devices with significantly more than 12, in particular 48, electrochemical cells.

Proceeding from the prior art listed above, it is an object of the present invention to specify a device which eliminates the above-mentioned problems and disadvantages of the prior art. In particular, it is an object of the present invention to specify a cell contacting system that has a simple structure, can be produced inexpensively and is particularly suitable for large electrochemical devices.

DISCLOSURE OF THE INVENTION

The object is achieved with a device according to claim 1 and a method according to claim 12. Advantageous developments of the invention are the subject matter of the dependent claims.

The solution according to the invention consists in particular in specifying a cell contacting system for an electrochemical device which has a plurality of electrochemical cells, the cell contacting system having the following: a large number of cell connectors for the electrically conductive connection of a large number of electrochemical cells, in particular for the electrically conductive connection of cell terminals of different types electrochemical cells; a plurality of contacting wires for contacting the cell connectors for voltage tapping of the electrochemical cells; a holding device made of a three-dimensional integral plastic film molding for holding the plurality of cell connectors and the plurality of bonding wires.

The electrochemical device can be an energy storage device with a number of energy storage cells, for example lithium-ion cells.

The cell connectors are preferably in one piece, but can, for example, be made in several layers. The cell connectors are designed to connect a first cell terminal of a first electrochemical cell to a second cell terminal of a second electrochemical cell. The cell connector has a first contact area for connecting to the first cell terminal and a second contact area for connecting to the second cell terminal. The two contact areas are connected to one another in one piece. A compensation area can be arranged between the two contact areas in order to enable a movement of the contact areas relative to one another.

The bonding wires are formed from an electrically conductive material and preferably have an outer insulating layer.

The holding device is produced as a three-dimensional, one-piece plastic film molding from a deep-drawn plastic film. The holding device has been given a three-dimensional structure during deep-drawing. The holding device is in particular a so-called blister. Overall, the holding device is preferably at least essentially plate-shaped and can have a rectangular basic shape. The holding device is designed to be placed directly on the electrochemical cells or their cell terminals. The holding device preferably has a length of at least 60 cm, preferably at least 100 cm, particularly preferably about 200 cm.

The advantage of the cell contacting system is in particular that the cell contact tion system is particularly easy and inexpensive to produce. Using a plastic sheet molding instead of an injection molding is easy and saves costs. In the case of larger holding devices in particular, costs can be saved by dispensing with injection molding tools. On the one hand, the use of contacting wires instead of an FPC has the advantage that the intrinsic mass of the contacting device can be kept particularly low by the contacting wires. As a result, the contact is less susceptible to vibration than the usual contact when using an FPC with a contact pad. In addition, costs can be saved by the contacting wires.

According to an advantageous development of the invention, the holding device has positioning structures for the cell connectors and/or guide structures for the contacting wires.

The structures are introduced during deep-drawing of the holding device. This results in a simple possibility of holding the cell connectors and/or contacting wires on the holding device in a form-fitting manner. The guide structures also serve in particular to guide the contacting wires from one longitudinal end of the holding device along the length of the holding device to the corresponding cell connector. At least some of the guide structures are designed in the form of ribs and extend parallel to the longitudinal edges of the holding device.

An advantageous development of the invention provides that the holding device is designed as a protection against accidental contact to cover the electrochemical cells.

This prevents a user from accidentally touching one of the cell terminals. The holding device is preferably designed in such a way that it has no passages except for positions at which the cell connectors are arranged on the holding device.

In a further advantageous development of the invention, the holding device has a thickness or layer thickness of 0.5 mm to 3 mm. The holding device preferably has a thickness of approximately 1.5 mm.

As a result, the holding device has sufficient stability, especially in the case of a larger size, i.e. length.

An advantageous development of the invention provides that the cell connectors have a welding hook for electrically conductive connection to the contacting wires. In particular, each cell connector has a welding hook for connection to a respective contacting wire.

The cell connectors can, for example, be at least essentially U-shaped, with the welding hook then preferably being arranged on one of the legs. The welding hook enables a contacting wire to be attached to the welding hook particularly quickly.

In an advantageous development of the invention, the contacting wires are in the form of enamelled copper wires.

Enamelled copper wires are particularly cheap and readily available. The contacting wires preferably have a diameter of between 0.3 mm and 0.6 mm, preferably approximately 0.4 mm, in particular independently of their material.

According to an advantageous development of the invention, the contacting wires have contacting loops for electrically conductive connection to the cell connectors.

In particular, each contacting wire has a contacting loop for connection to a respective cell connector.

In particular in combination with the welding hooks of the cell connectors, it is possible to ensure that the contacting wire is held securely on the cell connectors. Furthermore, the connection by means of welding hooks and contacting wire with a contacting loop can be carried out quickly.

In a further advantageous development of the invention, the contacting wires are routed to the outside and arranged outside in a common connector for direct connection to a battery management system or a cell monitoring circuit.

Outside here means outside of the cross section of the holding device in a top view of the holding device. The battery management system is a Battery Management System (BMS), and the cell monitoring circuit is a Cell Supervision Circuit (CSC). This enables a simple connection to a monitoring system. In the event of vibration, the connector of an FPC is often exposed to many bending cycles, which can lead to failure of the interface. This can be prevented by suitably guiding the contacting wires outwards and suitably arranging them in a common connector.

In an advantageous development of the invention, the common connector is designed as an insulation displacement connector.

This eliminates cable convection. A simple, robust and inexpensive system is created, especially in combination with enameled copper wires.

According to an advantageous development of the invention, the cell contacting system has at least one temperature sensor, the temperature sensor having welding hooks for connecting to the corresponding contacting wires.

The temperature sensors are preferably arranged on the cell connectors. In this case, the positioning structures, which are used to position the corresponding cell connector, can also be used to position the temperature sensor at the same time. In the case of a U-shaped cell connector, the temperature sensor is particularly preferably arranged on the leg that is not connected to a contacting wire.

An advantageous development of the invention provides that the cell contacting system has an insulating film for protecting and fixing the contacting wires on the holding device, the holding device having a multiplicity of fastening structures for fastening the insulating film to the holding device.

For example, the insulating film can be welded or glued to the attachment structure.

Furthermore, the object is achieved by means of a method for producing a cell contacting system, the method having the following steps: deep-drawing a plastic film to form a holding device; placing a plurality of cell connectors on the fixture; arranging a multiplicity of contacting wires for contacting the cell connectors for voltage tapping of the electrochemical cells on the holding device; and electrically conductively connecting the bonding wires to the cell connectors.

Since the cell contacting system that can be produced in the method can be one of the cell contacting systems already described, all individual aspects and advantages of the individual cell contacting systems can be transferred here. In particular, the manufacturing method is particularly simple and inexpensive and is particularly suitable for manufacturing long cell contacting systems. These cell contacting systems can have a length of more than 60 cm, preferably more than 100 cm and particularly preferably about 200 cm.

According to an advantageous development of the invention, a contacting loop of a contacting wire is welded to a welding hook during the electrically conductive connection of the contacting wires to the cell connectors.

In general, the dimensioning of the cell contacting system depends on the total voltage of the electrochemical device or the battery module. Until now, the module voltage was usually kept below 60 V in accordance with the low-voltage directive. With the progress of the cell-to-system approach in the installation of battery systems and the associated reduction in volumetric energy density, this will hardly be practicable in the future. The cell contacting system according to the invention can therefore be used in particular for a 48s1p interconnection. It has a length of about 2 meters and the electrochemical device achieves a nominal voltage of about 175.2 V. A 5s connection of the 48s1 p-connection corresponds to an 800V system. In this regard, parallel interconnections, such as a 24s2p interconnection, would of course also be possible.

character list

• 1 eine schematische Darstellung eines Zellkontaktierungssystem gemäß der vorliegenden Erfindung;
• 2 eine vergrößerte schematische Detailansicht des in 1 gezeigten Zellkontaktierungssystems ohne Darstellung einer Isolierfolie; und
• 3 eine schematische Darstellung eines Zellverbinders gemäß der vorliegenden Erfindung.

The different and exemplary features described above can be combined with one another according to the invention, insofar as this is technically meaningful and suitable. Further features, advantages and embodiments of the invention result from the following description of exemplary embodiments and with reference to the figures. Show it:

• 1 a schematic representation of a cell contacting system according to the present invention;
• 2 an enlarged schematic detail view of the in 1 shown cell contacting system without showing an insulating film; and
• 3 a schematic representation of a cell connector according to the present invention.

EXEMPLARY EMBODIMENTS OF THE INVENTION

1 shows a schematic representation of a cell contacting system 100 according to the present invention. In this case, only a right-hand part of the cell contacting system 100 is shown in FIG 1 shown. However, the remainder of the cell contacting system 100 that is not shown is designed like the part shown. Also is an electrochemical pro Direction 200 only indicated schematically by means of two cells 210.

The cell contacting system 100 has a holding device 130 which is formed from a one-piece three-dimensional molded plastic film part. In this case, the holding device 100 has a plurality of structures which are used to arrange elements on the holding device 100 . To clarify the difference from the prior art, the upper half of the cell contacting system 100 is shown schematically with an FPC. In reality, however, the upper half has the same structure as the lower half.

Like in the 1 indicated, the cell contacting system 100 is at least essentially a molded part in a rectangular plate-like basic shape with three-dimensional structures.

In a lower area of the cell contacting system 100, a multiplicity of cell connectors 110 are shown, which the cell contacting system 100 has in order to connect a multiplicity of electrochemical cells 210 to one another. In this case, the cell connectors 110 connect a first cell terminal of a first electrochemical cell 210 to a second cell terminal of a second electrochemical cell 210. One or more temperature sensors 150 are also arranged in order to enable the temperature of the electrochemical device 200 or its electrochemical cells 210 to be monitored.

A contacting device in the form of a contacting wire 120 is electrically conductively connected to the cell connectors 110 and the temperature sensors 150, the contacting wires 120 in FIG 1 are covered by an insulating film 160. This insulating film 160 serves on the one hand as protection and on the other hand as a fixation for the contacting wires 120. The contacting wires 120 are guided outwards from the holding device 130 and end there in a common connector 140.

The components cell connector 110, temperature sensor 150 and contacting wire 120 are the components previously referred to more generally as elements.

2 FIG. 12 shows an enlarged view of the cell contacting system 100, the insulating film 160 not being shown here in order to be able to show the structure of the system more clearly.

The holding device 130 has as below 1 several structures already indicated, which are introduced into the preliminary product, which is present as a film, for the holding device 130 during deep-drawing. The structures are positioning structures 131, guiding structures 132 and fastening structures 133.

The positioning structures 131 serve to position the cell connectors 110 on the holding device 130, ie to fix their position in a form-fitting manner. Like in the 2 clearly recognizable, a positioning structure 131 can also serve to position a temperature sensor 150 in addition to the cell connector 110 at the same time. Here, for example, both the cell connector 110 and the temperature sensor 150 have a bore into which a positioning structure 131 designed as a projection protrudes.

The guide structures 132 serve to guide the bonding wires 120 . At least some of the guide structures 132 are designed as ribs running parallel to the length of the holding device 130 , between which the contacting wires 120 can be arranged along the length of the holding device 130 .

Furthermore, the attachment structures 133 are primarily designed to provide an attachment option, in particular an attachment surface, for the insulating film 160 . In this case, the insulating film 160 can be applied to the fastening structure 133 by means of gluing or welding, for example.

It goes without saying that the functional elements positioning structure 131, guiding structure 132 and fastening structure 133 do not have to be separate functional elements. Rather, a functional element can be configured as a fastening structure 133 and a guide structure 132 at the same time, for example.

In the 3 An enlarged view of cell connector 110 is shown. The cell connector 110 has a first contact area 110a and a second contact area 110b. The first contact area 110a is used for the electrically conductive connection to a cell terminal of a first electrochemical cell 210 and the second contact area 110b is used for the electrically conductive connection to a cell terminal of a second electrochemical cell 210. Between the first contact area 110a and the second contact area 110b is a compensation area 110c educated. The compensation area 110c is in particular an area which has an arc or wave shape.

The cell connector 110 has two bores 110d in order to be able to arrange it on the holding device 130 in a form-fitting manner. An example is one of the two holes 110d as Round hole and one of the two holes 110d designed as a slotted hole.

The cell connector 110 is at least essentially U-shaped and has two legs. The cell connector 110 has a welding hook 111 at a front end of one of the legs. The welding hook 111 is an upturned hook and serves as shown in FIG 2 shown to come into engagement with a bonding loop 121 of bonding wire 120 . This makes positioning before welding much easier.

The temperature sensor 150 also has a welding hook 151 . In particular, the temperature sensor 150 has two welding hooks 151 in order to be able to connect the temperature sensor 150 to two contacting wires 120 .

It goes without saying that in the case of the present invention there is a relationship between, on the one hand, features that have been described in connection with method steps and, on the other hand, features that have been described in connection with corresponding devices. Thus, method features described are also to be regarded as device features belonging to the invention—and vice versa—even if this was not explicitly mentioned.

It should be noted that the features of the invention described with reference to individual embodiments or variants, such as the type and design of the individual components and their exact dimensioning and spatial arrangement, can also be present in other embodiments, unless otherwise stated or is automatically prohibited for technical reasons. In addition, of such features of individual embodiments described in combination, not all features necessarily have to be implemented in a relevant embodiment.

Reference List

100

cell contacting system

110

cell connector

110a

first contact area

110b

second contact area

110c

compensation area

110d

drilling

111

welding hook

120

bonding wire

121

contact loop

130

holding device

131

positioning structure

132

management structure

133

mounting structure

140

common connector

150

temperature sensor

151

welding hook

160

insulating film

200

electrochemical device

210

electrochemical cell

Claims (13)

Cell contacting system (100) for an electrochemical device (200) having a plurality of electrochemical cells (210), the cell contacting system (100) having: - a plurality of cell connectors (110) for electrically conductively connecting a plurality of electrochemical cells; - A multiplicity of contacting wires (120) for contacting the cell connectors (110) for voltage tapping of the electrochemical cells (210); - A holding device (130) made of a three-dimensional one-piece plastic film molding for holding the plurality of cell connectors (110) and the plurality of bonding wires (120). Cell contacting system (100) according to claim 1 , characterized in that the holding device (130) has positioning structures (131) for the cell connectors (110) and/or guide structures (132) for the contacting wires (120). Cell contacting system (100) according to claim 1 or 2 , characterized in that the holding device (130) is designed as a protection against accidental contact to cover the electrochemical cells (210). Cell contacting system (100) according to one of the preceding claims, characterized in that the holding device (130) has a thickness of 0.5 mm to 3 mm. Cell contacting system (100) according to one of the preceding claims, characterized in that the cell connectors (110) have a welding hook (111) for electrically conductive connection to the contacting wires (120). Cell contacting system (100) according to one of the preceding claims, characterized in that the contacting wires (120) are constructed as enameled copper wires. Cell contacting system (100) according to one of the preceding claims, characterized in that the contacting wires (120) have contacting loops (121) for electrically conductive connection to the cell connectors (110). Cell contacting system (100) according to one of the preceding claims, characterized in that the contacting wires (120) are routed to the outside and are arranged outside in a common connector (140) for direct connection to a battery management system or a cell monitoring circuit. Cell contacting system (100) according to claim 8 , characterized in that the common connector (140) is designed as an insulation displacement connector. Cell contacting system (100) according to one of the preceding claims, characterized in that the cell contacting system (100) has at least one temperature sensor (150), the temperature sensor (150) having welding hooks (151) for connecting to the corresponding contacting wires (120). Cell contacting system (100) according to one of the preceding claims, characterized in that the cell contacting system (100) has an insulating film (160) for protecting and fixing the contacting wires (120) on the holding device (130), the holding device (130) having a plurality of Fastening structures (133) for fastening the insulating film (160) to the holding device (130). Method for producing a cell contacting system (100), in particular according to one of the preceding claims, characterized in that the method has the following steps: - thermoforming a plastic film to form a holding device (130); - arranging a plurality of cell connectors (110) on the holding device (130); - arranging a plurality of contacting wires (120) for contacting the cell connectors (110) for voltage tapping of the electrochemical cells (210) on the holding device (130); and - electrically conductive connection of the contacting wires (120) to the cell connectors (110). Method for producing a cell contacting system (100). claim 12 , characterized in that when electrically conductively connecting the contacting wires (120) to the cell connectors (110), a contacting loop (121) of a contacting wire (120) is welded to a welding hook (111).

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