DE102015007615A1 - Connecting element for the electrical connection of single cells, cell block and electric battery - Google Patents

Abstract

The invention relates to a connecting element (3) for the electrical connection of individual cells (2). According to the invention, the connecting element (3) comprises a current busbar (4) and a cell connector (5), wherein the busbar (4) and the cell connector (5) are electrically connected to each other and arranged against each other, the cell connector (5) for electrically contacting more than two single cells (2) is formed and the current collecting rail (4) extends at least over a length of the cell connector (5). The invention further relates to a cell block (1) for an electric battery (7) having a plurality of individual cells (2), wherein more than two individual cells (2) are electrically interconnected by means of a connecting element (3), and an electric battery (7 ) comprising a plurality of such cell blocks (1).

Description

The invention relates to a connection element for the electrical connection of individual cells, a cell block for an electric battery and an electric battery comprising a plurality of such cell blocks.

From the DE 10 2013 209 391 A1 is a battery module, also referred to as a cell block, from a number of each interconnected battery cells, also known as single cells known. The battery cells are accommodated in a hard shell housing, in which two current busbars for the electrical connection of the battery cells run as connecting elements. The two busbars extend through the hard shell housing and contact the battery cells each at their end faces.

Furthermore, cell blocks for electric batteries, each having a plurality of individual cells interconnected electrically, are generally known from the prior art. The electrical interconnection of the individual cells takes place by means of connecting elements, which are designed as solid and each point-welded with high voltage cell poles of the individual cells. The cell connectors are integrally formed and connect more than two individual cells each other electrically.

The invention is based on the object to provide a comparison with the prior art improved connection element for the electrical interconnection of single cells, an improved cell block for an electric battery and an improved electric battery.

With regard to the connecting element, the object is achieved by the features specified in claim 1, in terms of the cell block by the features specified in claim 7 and in terms of the electric battery by the features specified in claim 10.

Advantageous embodiments of the invention are the subject of the dependent claims.

According to the invention, the connecting element for electrically interconnecting individual cells comprises a busbar and a cell connector, wherein the busbar and the cell connector are electrically connected and arranged to one another, the cell connector is designed for electrical contacting of more than two individual cells and the busbar is at least over a length of Cell connector extends.

By means of the connecting element and the integral formation of current busbar and cell connector for more than two individual cells, a significant reduction of a number of parts and thus a considerably simplified handling during assembly of the connecting element and its mounting to the individual cells is achieved compared to separate cell connectors for every two individual cells. In particular, a complex positioning and alignment of multiple cell connectors are avoided for power bus and a mounting effort and material and parts costs can be reduced.

Embodiments of the invention are explained in more detail below with reference to drawings.

Showing:

1 1 is a schematic perspective view of an exploded view of a cell block according to the prior art;

2 schematically an exploded view of the cell block according to 1 on average,

3 schematically a first embodiment of a connecting element according to the invention in a disassembled and a mounted state,

4 1 is a schematic perspective view of an exploded view of a first embodiment of a cell block according to the invention;

5 schematically a perspective view of the cell block according to 4 in the assembled state,

6 schematically a perspective view of a section of the cell block according to 4 during a welding of a cell connector to a single cell,

7 schematically a perspective view of the section of the cell block according to 6 after welding the cell connector to the single cell,

8th schematically a sectional view of the section of the cell block according to 7 .

9 schematically a sectional view of the cell block according to 5 .

10 schematically a sectional view of a section of the cell block according to 5 in the area of a fusion of the cell connector with the Single cell and a busbar of the connecting element,

11 schematically a perspective view of an exploded view of a section of a plurality of cell blocks according to 5 comprehensive electric battery,

12 schematically a second embodiment of a connecting element according to the invention in a disassembled and a mounted state,

13 1 is a schematic perspective view of a section of a second embodiment of a cell block according to the invention during a welding of a cell connector with a single cell;

fourteen schematically a sectional view of the section of the cell block according to 13 .

15 1 schematically a perspective view of an exploded view of a third exemplary embodiment of a cell block according to the invention with a third exemplary embodiment of a connecting element according to the invention,

16 schematically a perspective view of the cell block according to 15 in the assembled state,

17 schematically a sectional view of the cell block according to 16 .

18 schematically a fourth embodiment of a connecting element according to the invention in a disassembled and a mounted state,

19 1 is a schematic perspective view of an exploded view of a fourth embodiment of a cell block according to the invention;

20 schematically a perspective view of the cell block according to 19 in the assembled state,

21 1 is a schematic perspective view of an exploded view of a fifth embodiment of a cell block according to the invention;

22 schematically a perspective view of the cell block according to 21 in the assembled state,

23 1 is a schematic perspective view of an exploded view of a sixth embodiment of a cell block according to the invention;

24 schematically a perspective view of the cell block according to 23 in the assembled state,

25 schematically a sectional view of a section of the cell block according to

24 in the area of a welding of the cell connector to the single cell and a current busbar of the connecting element,

26 1 is a schematic perspective view of an exploded view of a seventh embodiment of a cell block according to the invention;

27 schematically a perspective view of the cell block according to 26 in the assembled state.

Corresponding parts are provided in all figures with the same reference numerals.

In the 1 and 2 is an exploded view of a cell block in various views 1 illustrated in the prior art for an electric battery, not shown.

The electric battery is a so-called high-voltage battery, which, for example, for vehicle application such. In hybrid, plugin or electric vehicles, or for stationary applications, e.g. B. as electricity supplier or electricity storage is used.

The cell block 1 includes in the illustrated embodiment, five electrically interconnected individual cells 2 , To form a high-voltage battery, a plurality of cell blocks 1 electrically connected in series and / or in parallel. To this electrical interconnection comprises the cell block 1 two connecting elements 3 , wherein the connecting elements 3 each a power bus 4 and five cell connectors 5 include. By means of the cell connectors 5 become the single cells 2 electrically connected in parallel with each other and electrically connected to the busbars 4 interconnects which electrical poles of the cell block 1 form.

The illustrated single cells 2 are designed as round cells with a metal housing and for space and cost reasons without pronounced cell poles. Under pronounced cell poles are led out of a housing base metal lugs or metal pins understood, at which, for example by means of welding or screwing the cell connectors 5 be attached.

To a height of the connecting element 3 To minimize as possible, include the busbars 4 one each with the cell connectors 5 corresponding recess A, in which the cell connectors 5 are each arranged at least in sections.

Is the connection of the cell connectors 5 to the individual cells 2 To ensure a low electrical resistance, a high mechanical strength and to prevent corrosion and contact corrosion by means of material connection, then a particularly low heat input welding process is used for this purpose. As a result, an excessive heat input into a directly below a joint between individual cell 2 and cell connectors 5 within the single cell 2 prevents electrochemically active material located, which is irreversibly damaged or destroyed at temperatures of more than 65 ° C, for example, when trained as lithium-ion cell chemistry. For this reason, the production of the joint takes place for example by means of resistance pressure welding, such. As a spot welding or capacitor discharge welding, or by means of bonding, ultrasonic welding or laser welding.

For generating the cohesive connection between the cell connectors 5 and the single cells 2 after an arrangement of the connecting element 3 at the single cells 2 have the busbars 4 each with a number of single cells 2 corresponding number of openings D, through each of which a tool for generating the cohesive connection can be guided. In the other 3 to 27 is for the sake of clarity, only one breakthrough D per busbar 4 provided with a reference numeral.

As a wall thickness of the metal housing of the individual cells 2 in the area of the joint to the cell connector 5 is very small, for example, 0.2 mm to 0.5 mm, is a cell connector 5 used with a small thickness. In doing so, the thickness of the cell connector becomes 5 chosen smaller than the wall thickness of the metal housing, in order to avoid a so-called Durchschweißung of the metal housing and a resulting opening of the same. Due to the small thickness of the cell connector 5 can the heat input during the production of cohesive connection between cell connectors 5 and single cell 2 be reduced further, since less material must be melted for joining.

However, a disadvantage is the low material cross section of the cell connector 4 caused high ohmic losses during operation of the cell block 1 , In particular, in an electrical parallel connection of the individual cells 2 Therefore, as shown, cell connectors 5 used with short length, which is close to single cells 2 on a massive power bus 4 are fixed. By means of the current busbars 4 the parallel connection of the individual cells takes place 2 with large conductor cross-section and thus reduced contact resistance.

To generate the high-voltage battery are several cell blocks 1 electrically connected in parallel and / or in series with each other, wherein the busbars 4 for this interconnection one, in the illustrated embodiment as a threaded bore formed connecting element 4.1 exhibit.

A disadvantage of the illustrated embodiment according to the prior art, however, is the large number of required cell connectors 5 as well as a resulting great expense for their positioning and alignment prior to the generation of the cohesive connection between cell connectors 5 and single cell 2 as well as between cell connectors 5 and power bus 4 ,

3 shows a possible first embodiment of a connecting element according to the invention 3 in a disassembled state (upper illustration) and an assembled state (lower illustration).

In contrast to the known from the prior art and in the 1 and 2 The solution shown comprises the connecting element 3 a cell connector 5 , which is used for electrical contacting of more than two individual cells 2 , In the illustrated embodiment five individual cells 2 , is trained.

The power bus 4 and the one-piece cell connector 5 are electrically connected to each other and arranged together, wherein the current busbar 4 at least over a length of the cell connector 5 extends.

Furthermore, the cell connector 5 and the power bus 4 arranged such that in the current busbar 4 formed breakthroughs D from the cell connector 5 at least partially covered. Here is the cell connector 5 arranged in the openings D connecting recess A, which is in particular designed as a cutout and with the cell connector 5 corresponds. The recess A further facilitates alignment and positioning of the respective cell connector 5 to the associated busbar 4 ,

The cell connectors 5 are as sheet metal strips, ie band-shaped and punctiform by means of a spot welding process with the respective busbar 4 connected. For example, the cell connectors 5 made of copper, aluminum or steel with a thickness of 0.1 mm to 0.5 mm. Here is the respective cell connector 5 at each two edge regions of the openings D electrically connected to the busbar 4 connected so that a contact resistance between the cell connector 5 and the power bus 4 is low.

To simplify the welding of cell connectors 5 and power bus 4 has the cell connector 5 in a possible embodiment, a surface coating, which in a formation of the cell connector 5 is formed of copper or steel of nickel or tin.

The power bus 4 is solid and made of a metal, such as copper, aluminum or brass, formed and is also provided in a possible embodiment with a surface coating, which in a formation of the busbar 4 is formed of copper, for example, nickel or tin. Due to the massive design of the power busbar 4 this has a large conductor cross-section.

In the 4 to 10 is in various views and views a first embodiment of a cell block according to the invention 1 shown which five single cells 2 and two fasteners 3 according to 3 includes. Here are all positive poles of the single cells 2 by means of a connecting element 3 and all negative poles of the single cells 2 by means of a further connecting element 3 connected.

Also the electrical connection between the single cells 2 and the cell connectors 5 takes place by welding, in the illustrated embodiment in a spot welding process. Here are the first assembled fasteners 3 (Busbar 4 and cell connectors 5 are welded) on the single cells 2 arranged and aligned then the welding of the cell connector takes place 5 with the single cells 2 , For this purpose, a welding tool 6 , which comprises two spot welding electrodes, through the openings D on a surface of the respective cell connector 5 guided and this is with the single cell 2 welded.

Due to the small thickness of the cell connector 5 For example, a welding process can be used which requires only minimal heat input into the individual cells 2 generated.

Due to the fact that the respective cell connector 5 at each two edge regions of the openings D with the busbar 4 (represented by joints F3, F4) and at the joints F1, F2 with the single cell 2 is connected according to 10 a current flow through two different paths possible, so that the electrical contact resistance between the single cell 2 and the power bus 4 and resistive losses are reduced.

11 shows a perspective view of an exploded view of a section of a possible embodiment of a plurality of cell blocks 1 according to 5 comprehensive electric battery 7 ,

For electrical series connection of the cell blocks 1 are several fasteners 8th , also referred to as bridge, provided, which with the connecting elements 4.1 the busbars 4 get connected.

12 shows a possible second embodiment of the connecting element according to the invention 3 in a disassembled state (upper illustration) and an assembled state (lower illustration).

Unlike the in 3 illustrated first embodiment, the cell connector 5 a plurality of slot-shaped openings S, which are arranged such that these between two adjacent welding points, ie between the two spot welding electrodes of the welding tool 6 run.

In the 13 and fourteen is in various views a section of a second embodiment of the cell block according to the invention 1 during a fusion of the cell connector 5 according to 12 with a single cell 2 shown.

Due to the slot-shaped openings S between the spot welding electrodes of the welding tool 6 For example, a welding current (represented by a dashed line) is directed through the joints F1, F2, so that a short circuit effect of the cell connector 5 during welding is prevented.

The 15 to 17 show in different views a third embodiment of the cell block according to the invention 1 with a third embodiment of the connecting element according to the invention 3 , Unlike the in 3 illustrated first embodiment of the connecting element 3 have the busbars 4 the recess A respectively at its top, ie at one of the individual cells 2 on the opposite side. The cell connector 5 has several cranks which are arranged such that they through the openings D to the individual cells 2 protrude. In the remaining areas is the cell connector 5 arranged within the recess A.

18 shows a possible fourth embodiment of the connecting element according to the invention 3 in a disassembled state (upper illustration) and an assembled state (lower illustration).

Unlike the in 3 The first embodiment shown is the cell connector 5 such on an upper side of the busbar 4 arranged that this in the assembled state on in the 19 and 20 closer cell block 1 laterally to the single cells 2 runs. On top of the power bus 4 is the cell connector 5 several times with the power bus 4 spot-welded.

The cell connector 5 has several, at a distance of the individual cells 2 arranged and trained in the direction of these surveys E, in the area of which the cell connectors 5 with the single cells 2 is welded.

The 19 and 20 show in various views a possible fourth embodiment of the cell block 1 with five electrically connected single cells 2 and two connectors 3 according to 18 ,

In the 21 and 22 is in various views a possible fifth embodiment of the cell block according to the invention 1 with a possible fifth embodiment of the connecting element according to the invention 3 shown. Unlike the ones in the 18 to 20 The illustrations shown are the elevations E of the cell connector 5 formed on tab-shaped areas. The comb-like cell connector thus formed 5 can be manufactured with a particularly low material usage and is characterized by a low weight. Due to a slight deformability of the tab-shaped areas is a simple compensation of dimensional tolerances of the individual cells 2 given along the vertical axis and thus an electrical connection between the connecting element 3 and single cells 2 always ensured.

The 23 to 25 show in various views a possible sixth embodiment of the cell block according to the invention 1 with a possible sixth embodiment of the connecting element according to the invention 3 ,

Unlike in the 15 to 17 illustrated third embodiment of the connecting element according to the invention 3 are the also cranked shaped cell connectors 5 designed as a bonding wire and both with the associated power bus 4 as well as with the single cells 2 bonded.

The cranks of the cell connector 5 are arranged such that these through the openings D to the individual cells 2 protrude. In the remaining areas is the cell connector 5 on a top of the power bus 4 arranged. In non-illustrated embodiments, the power bus 4 in these remaining areas one to the cell connector 5 corresponding recess A on.

The bonding wire, for example, has a thickness of about 0.5 mm and is formed, for example, of copper or aluminum.

Also in the training of the cell connector 5 As a bonding wire this is at two edge regions of the openings D in the region of the joints F3, F4 electrically connected to the busbar 4 connected so that a contact resistance between the cell connector 5 and the power bus 4 is low.

The 26 and 27 show in various views a possible seventh embodiment of the cell block according to the invention 1 with a possible seventh embodiment of the connecting element according to the invention 3 ,

Unlike in the 21 and 22 illustrated fifth embodiment of the cell block according to the invention 1 with the fifth embodiment of the connecting element according to the invention 3 are the cell connectors 5 designed as a bonding wire, wherein the tab-shaped areas are formed by corresponding formations of the bonding wire.

The trained as a bonding wire cell connector 5 is so on an upper side of the busbar 4 arranged that this in the mounted state on the cell block 1 laterally to the single cells 2 runs. On top of the power bus 4 is the cell connector 5 several times with the power bus 4 bonded.

LIST OF REFERENCE NUMBERS

1

cell block

2

single cell

3

connecting element

4

Busbar

4.1

connecting element

5

cell connectors

6

welding tool

7

battery

8th

connecting element

A

recess

D

breakthrough

e

survey

F1 to F4

joint

S

breakthrough

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102013209391 A1 [0002]

Claims (10)

Connecting element ( 3 ) for the electrical interconnection of individual cells ( 2 ), characterized by - a power bus ( 4 ) and - a cell connector ( 5 ), wherein - the power bus ( 4 ) and the cell connector ( 5 ) are electrically connected to one another and arranged one against the other, - the cell connector ( 5 ) for the electrical contacting of more than two single cells ( 2 ) is formed and - the current busbar ( 4 ) at least over a length of the cell connector ( 5 ). Connecting element ( 3 ) according to claim 1, characterized in that the current busbar ( 4 ) has a plurality of openings (D), wherein the cell connector ( 5 ) and the power busbar ( 4 ) are arranged to each other such that the openings (D) from the cell connector ( 5 ) are at least partially covered. Connecting element ( 3 ) according to claim 2, characterized in that the cell connector ( 5 ) at each of a plurality of edge regions of the openings (D) electrically connected to the current busbar ( 4 ) connected is. Connecting element ( 3 ) according to one of the preceding claims, characterized in that the cell connector ( 5 ) with the power busbar ( 4 ) is welded. Connecting element ( 3 ) according to one of the preceding claims, characterized in that the cell connector ( 5 ) is designed as a sheet metal strip. Connecting element ( 3 ) according to one of claims 1 to 3, characterized in that the cell connector ( 5 ) is designed as a bonding wire and with the current busbar ( 4 ) and the single cells ( 2 ) is bonded. Cell block ( 1 ) for an electric battery ( 7 ) with - a plurality of individual cells ( 2 ), Where more than two single cells ( 2 ) by means of a connecting element ( 3 ) are electrically interconnected according to one of the preceding claims. Cell block ( 1 ) according to claim 7, characterized in that - the individual cells ( 2 ) are electrically connected to each other in parallel, wherein - positive poles of the individual cells ( 2 ) by means of the connecting element ( 3 ) and - minus poles of the single cells ( 2 ) by means of a further connecting element ( 3 ) are connected. Cell block ( 1 ) according to claim 7 or 8, characterized in that the cell connector ( 5 ) of the connecting element ( 3 ) with pole contacts of the individual cells ( 2 ) is welded or bonded. Electric battery ( 7 ) comprising a plurality of cell blocks ( 1 ) according to one of claims 7 to 9, wherein the busbars ( 4 ) of the connecting elements ( 3 ) of the cell blocks ( 1 ) are electrically interconnected.

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