DE102016005967A1 - Cell module for a motor vehicle battery - Google Patents

Abstract

The invention relates to a cell module (10) for a motor vehicle battery (11), comprising a plurality of battery cells (12), and a bus bar (13) connecting the battery cells (12) in an electrical parallel connection, the bus bar (13 ) forms a cell holder mechanically fixing the battery cells (12) in at least two directions, and a method of manufacturing such a cell module (10).

Description

The invention relates to a cell module for a motor vehicle battery and a method for producing such a cell module.

From the WO 2011/33727 A1 is already known cell module for a motor vehicle battery, with a plurality of battery cells, and with a bus bar, which connects the battery cells in an electrical parallel circuit with each other.

The invention is in particular the object of simplifying a structure and / or assembly of such a cell module. It is achieved by an embodiment according to the invention according to claim 1 and an inventive method according to claim 10. Further developments of the invention will become apparent from the dependent claims.

The invention is based on a cell module for a motor vehicle battery, with a plurality of battery cells, and with a bus bar, which connects the battery cells in an electrical parallel connection with each other.

It is proposed that the busbar forms a cell holder which mechanically fixes the battery cells in at least two directions. In that the busbar is simultaneously formed as a cell holder for the individual battery cells, a number of components can be reduced. Due to the smaller number of components, a structure of the cell module can be simplified. In addition, a mounting can be simplified. A "battery cell" is to be understood in particular as a unit having a cell housing and an electrochemically active part for receiving, storing and / or delivering electrical power, wherein the cell housing has two contact surfaces which are provided for electrically contacting the electrochemically active part. The battery cell can basically have different shapes.

Preferably, the bus bar has at least two differently oriented inner sides, by means of which the battery cells are positively fixed in the at least two directions and / or can be fixed. As a result, a good fixation of the battery cells can be achieved. In this context, an "inner side" is to be understood as meaning, in particular, a surface of the busbar which, in the mounted state, faces the battery cells. Preferably, the at least two differently oriented inner sides span a space in which the battery cells are arranged.

In a particularly advantageous embodiment, the inner sides are at least partially opposite each other and the battery cells are arranged between the inner sides. This allows a particularly good backup of the battery cells can be achieved. By "inner sides facing each other" is meant in particular inner sides whose surface normals lie in common planes.

In a particularly advantageous embodiment, it is proposed that one of the inner sides of the busbar forms a base which is provided for making electrical contact with the battery cells. As a result, the battery cells can be connected in a particularly simple manner parallel to one another. In this context, an "inner side which forms a floor" is to be understood in particular to mean an inner side whose surface normals are oriented along a "vertical direction". A "vertical direction" should be understood to mean a direction which is oriented along the directions of longitudinal extension of the assembled battery cells, wherein the direction of longitudinal extension of the individual battery cells is preferably defined by the two opposing contact surfaces of the corresponding battery cell.

It is further proposed that each of the battery cells has an electrical contact surface, which are firmly connected to the bottom of the busbar designed as a bottom. As a result, in addition to the electrical connection, a thermally well-conductive connection to the power-conducting rail can be produced, by means of which the power-conducting rail can be used well for controlling the temperature of the battery cells. Also, by the battery cells are arranged between two inner sides of the busbar, a good temperature of the battery cells can be achieved. In particular, the design of the busbar as a cell holder enables a uniform and good temperature control of the battery cells.

It is further proposed that the bus bar has a contact tongue which is provided for electrically contacting battery cells of a cell module arranged adjacently. As a result, a connection of the individual cell modules in an electrical series circuit can be easily realized. In this context, a "contact tongue" should be understood as meaning, in particular, a part of the busbar which is provided for making electrical contact with all the battery cells of the adjacent cell module, thereby providing in the cell module a second contact rail, which is provided for this purpose, the further contact surfaces of the battery cells of the cell module to connect, can be dispensed with. Preferably, the cell module comprises only a single bus bar, which is intended to form a pole of the cell module.

It is further proposed that the cell module has at least one electrical insulation which is provided for electrical insulation in relation to a cell module arranged adjacently. As a result, an electrical connection of the cell modules by means of the busbar can be easily realized. The insulation is preferably arranged between the two cell modules and separates the busbars of adjacent cell modules from one another when the cell modules are arranged without play relative to one another.

Preferably, the cell module comprises a potting compound for fixing the battery cells, for which the busbar at least partially serves as a casting mold. As a result, a particularly simple fixation of the battery cells to the busbar is possible. In addition, a thermally good conductive mechanical connection between the battery cells and the busbar can be easily made. A "potting compound" is to be understood in this context in particular a mass which can be introduced after a fixation of the battery cells to the busbar in spaces between the battery cells and the busbar and after curing the battery cells and the power rail force and / or cohesive combines.

Furthermore, a cell block for a motor vehicle battery, in particular a high-voltage battery, with at least two cell modules according to the invention is proposed.

In addition, a method for producing a cell module according to the invention is proposed, in which the integrally designed bus bar designed as a bus bar is produced by means of a forming process. By manufacturing by a forming process, the busbar can be made particularly simple. Due to the one-piece design a simple production is possible. By "one piece" should be understood in particular at least materially connected connected, for example, by a welding process, a gluing process, a Anspritzprozess and / or another, the skilled person appear useful process, and / or advantageously formed in one piece, such as by a Manufacture from a casting, by production in a forming process and / or by production in a one- or multi-component injection molding process and advantageously from a single blank.

Further advantages will become apparent from the following description of the figures. In the figures, an embodiment of the invention is shown. The figures, the description of the figures and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations. Analogously designed components are designated in the figure description with the same reference numerals. To distinguish the analogously formed components whose reference numerals, if an assignment is necessary, provided with a dash.

Showing:

1 a motor vehicle with a motor vehicle battery,

2 a cell module of a cell block of the motor vehicle before assembly,

3 the cell module 2 in a second view with an attached insulation,

4 the cell block with a plurality of cell modules and

5 a section through one of the cell modules.

The 1 to 5 show a motor vehicle with a motor vehicle battery 11 , In the illustrated embodiment, the motor vehicle is designed as a hybrid vehicle. The motor vehicle includes a drive train with an electric motor 24 and an internal combustion engine 25 , both for driving drive wheels 26 are provided. Alternatively, it is also conceivable that the motor vehicle is designed as an electric vehicle and the drive train only the electric motor 24 includes. It is also conceivable that the motor vehicle has a decentralized drive concept with a plurality of electric motors, each directly for driving one of the drive wheels 26 are provided. The embodiment of the motor vehicle battery 11 is independent of the planned drive concept. In principle, the motor vehicle can also have a differently designed drive train. The motor vehicle battery 11 is designed as a high-voltage battery.

The motor vehicle battery 11 includes several cell blocks 23 , The cell blocks 23 comprise a plurality of battery cells 12 , which are provided for storage and delivery of electrical power. The cell blocks 23 as well as the battery cells 12 in the cell blocks 23 are electrically connected in parallel and / or in series to provide a voltage and power required for the powertrain. The battery cells 12 each have a cell voltage in the low voltage range, the cell voltage depends on a cell chemistry used. In an embodiment of the battery cells 12 as lithium-ion batteries, the cell voltage is 3.6 volts, for example. Basically, the Cell voltage but also have other values. The motor vehicle battery 11 indicates depending on the interconnection of the battery cells 12 a battery voltage, which may be in the low voltage range or in the high voltage range depending on a intended use. Is the motor vehicle battery 11 designed as a starter battery, the battery voltage may for example be 12 volts. In the illustrated embodiment, in which the motor vehicle battery 11 is designed as a high-voltage battery is the motor vehicle battery 11 for a battery voltage of 90 volts or more, in particular for a battery voltage of 120 volts, provided.

The motor vehicle battery 11 has a battery case 27 on, that's the cell blocks 23 with the battery cells 12 receives. Next comprises the motor vehicle battery 11 an electronics 28 , in particular for monitoring the battery cells 12 as well as for adjusting an electrical power to the battery cells 12 fed or the battery cells 12 is taken is provided. In addition, the motor vehicle battery includes 11 a tempering device 29 for the battery cells 12 and / or the electronics 28 which in particular for cooling and / or heating of the battery cells 12 is provided. The cell blocks 23 with the battery cells 12 , the Electronic 28 and the tempering device 29 are in the common battery case 27 arranged (cf. 1 ). The tempering device 29 includes a heat exchanger plate 30 , which thermally with the battery cells 12 in contact. The heat exchanger plate 30 has channels that are flowed through by a cooling water in one operation. The heat exchanger plate 30 can also be used to warm up the cell modules 10 be used.

The battery cells 12 are designed as round cells in the illustrated embodiment. They can be of a standard type, such as 18650, 26650, 32650, and so on. The battery cells 12 typically have a cell housing 31 in the form of a cylinder. The cell case 31 has a cell bottom and a cell lid, which contact surfaces 19 . 20 the battery cell 12 form. At the contact surface 19 , which is formed by the preferably at least substantially flat cell bottom, is usually the negative pole. At the contact surface 20 , which is formed by the preferably slightly raised cell cover, is usually the positive pole. The battery cell 12 may have a Ventingöffnung through which a, for example, in the case of short circuit or overcharging, constructed pressure in an electrolyte space can be reduced. The cell case 31 has a lateral surface 32 on, which may be covered for electrical insulation with a kind of heat shrink plastic or the like, which usually slightly around corners of the battery cell 12 is guided around and also covers parts of the cell bottom and the cell lid. The contact surfaces 19 . 20 define a longitudinal direction of extension of the battery cell 12 , The lateral surface 32 extends along the longitudinal direction between the contact surfaces 19 . 20 ,

The battery cells 12 have a capacity which is typically less than 10Ah. To the cell block 23 to provide with a higher capacity, are the battery cells 12 to cell modules 10 connected together. The battery cells 12 a cell module 10 are connected together in an electrical parallel circuit. The cell module 10 has a module voltage corresponding to the cell voltage. The individual cell modules 10 of the cell block 23 are connected together in an electrical series connection. The cell block 23 has a cell block voltage, which is the module voltage and a number of cell modules 10 depends.

To the battery cells 12 in the electrical parallel connection to each other, includes the cell module 10 a power rail 13 which is formed of an electrically conductive material. The busbar 13 is intended to be the contact surfaces 19 . 20 all battery cells 12 of the cell module 10 , which have a same polarity, to connect together. In addition, the busbar 13 for the electrical connection with the adjacent cell module 10 ' intended. The busbar 13 thus forms a pole of the cell module 10 out. In the illustrated embodiment, the bus bar 13 with the contact surfaces 19 . 20 the battery cells 12 connected, which form the minus poles.

The busbar 13 forms a cell holder that holds the battery cells 12 mechanically fixed in different directions. The busbar 13 is thus for the electrical and the mechanical connection of the battery cells 12 intended. The trained as a cell holder busbar 13 has several, the battery cells 12 facing insides 14 . 15 . 16 . 17 . 18 on. Each of the insides 14 . 15 . 16 . 17 . 18 fixes the battery cells 12 positive in one direction.

The illustrated busbar 13 shows the five inner pages oriented in different directions 14 . 15 . 16 . 17 . 18 on. Through the five insides 14 . 15 . 16 . 17 . 18 are the battery cells 12 fixed positively in five directions. The busbar 13 is only open on one side. Through the five insides 14 . 15 . 16 . 17 . 18 has the busbar 13 a cup shape from which the battery cells 12 be recorded. The two insides 14 . 15 fix the battery cells 12 in the direction parallel to a longitudinal direction 33 , The two insides 16 . 17 fix the battery cells 12 in the direction parallel to a transverse direction 34 , The fifth inside 18 fixes the battery cells 12 in the direction parallel to a vertical direction 35 ,

Due to the cup shape are the four inner sides 14 . 15 . 16 . 17 arranged in pairs opposite each other. The battery cells 12 are between the four insides 14 . 15 . 16 . 17 arranged. The four insides 14 . 15 . 16 . 17 form a beaker wall. The four insides 14 . 15 . 16 . 17 . 18 have surface normal, which is substantially parallel to the longitudinal direction 33 and the transverse direction 34 are oriented. The battery cells 12 are arranged side by side in the form of a stack for a densest ball packing. The insides 14 . 15 . 16 . 17 which the battery cells 12 fix in the four directions, have one to the stacking of the battery cells 12 adapted form. In the illustrated embodiment, in which the battery cells 12 are designed as round cells are the insides 14 . 15 . 16 . 17 wavy formed.

The fifth inside 18 the busbar 13 forms a bottom of the cup shape. The fifth inside 18 is for electrical contacting of the battery cells 12 intended. The formed as a bottom inside 18 is essentially flat. The negative pole forming contact surface 20 the battery cells 12 is solid, preferably cohesive, with the inside 18 the busbar 13 connected. In a production, the battery cells 12 on the formed as a bottom inside 18 the busbar 13 put on and then with the inside 18 welded, for example by overlap laser welding, one-sided spot welding, laser soldering or another, the expert appears to be useful method.

The busbar 13 is formed in one piece. Preferably, the busbar 13 of a metal or a metal alloy, in particular aluminum, an aluminum alloy, copper or a copper alloy. Trained as a cell holder, integrally running busbar 13 is produced by means of a forming process. The preparation preferably takes place from a sheet-like raw material in a deep-drawing process or by extrusion from ingot-shaped blanks. In principle, the busbar is also conceivable 13 from several components. Preferably, at least the part of the busbar 13 which the battery cells 12 mechanically fixed, produced by a forming process of a blank. The cell module shown 10 has a total of 29 round cells, which are connected together in an electrical parallel circuit. The cell block 23 includes six cell modules 10 , which are connected together in an electrical series connection. The busbar 13 consists of deep-drawn copper sheet, with the bottom forming the inside 18 in areas that connect to the contact surfaces 20 the battery cells 12 is provided, is provided with indentations, which a backlash-free contact surfaces 20 enable. The battery cells 12 are by a laser overlap welding to the power rail 13 fixed. Additionally or alternatively, it is also conceivable, the battery cells 12 to fix positively, for example by the through the insides 14 . 15 . 16 . 17 formed beaker wall is flattened inwardly at an upper edge. In addition, the battery cells can 12 by gluing to the busbar 13 get connected.

The cell module 10 has an electrical insulation, which for electrical insulation against the adjacent cell module 10 is provided. The insulation separates in particular the busbars 13 . 13 ' the neighboring cell modules 10 . 10 ' electrically from each other when the cell modules 10 . 10 ' in the cell block 23 mechanically interconnected. To form the insulation preferably thin plastic films or plates between the cell modules 10 inserted or on the busbars 13 the individual cell modules 10 postponed. Alternatively, it is also conceivable, the insulation on the busbar 13 stick on or the busbar 13 to coat on its outside with plastic. In the illustrated embodiment, the insulation by an over-pushed foil blister 36 made of plastic.

Next points the cell module 10 a potting compound 22 on which the battery cells 12 with the trained as a cell holder busbar 13 combines. The busbar 13 serves as a casting mold. In a production of the cell modules 10 become the battery cells 12 first with the busbar 13 connected. Subsequently, cavities between the battery cells 12 and the insides 14 . 15 . 16 . 17 . 18 the busbar 13 poured out. Through the cup shape forms the busbar 13 the casting mold for the potting compound.

To at least partially serve as a casting mold, the busbar must 13 at least the inside 18 , which forms the floor, and the inside 17 to which the contact tongue 21 is connected. Indicates the busbar 13 only a part of the illustrated insides 14 . 15 . 16 . 17 . 18 out, becomes the cell module in a production 10 used in a mold, which the battery cells 12 in directions in which the busbar 13 open, limited. After curing of the potting compound 22 has a cell module made in this way 10 Outer sides, which partly through the busbar 13 and partly by the potting compound 22 are formed. Is the outside, which is the contact tongue 21 opposite, by the potting compound 22 trained, can on one additional insulation can be dispensed with. In such a case, the potting compound forms 22 the electrical insulation, which is for electrical insulation against the adjacent cell module 10 ' is provided.

The potting compound 22 causes a thermal coupling of the battery cells 12 to the power rail. In the illustrated embodiment, the battery cells 12 along the transverse direction 34 arranged in two rows. Each of the battery cells 12 know by a similar thermal connection to the busbar 13 on. The double row ensures a uniform temperature of the battery cells 12 , which is particularly advantageous for parallel connection. The potting compound 22 preferably has admixtures which cause increased thermal conductivity, such as graphite.

The cell block 23 has a holding frame 37 , preferably of plastic, on, in which the cell modules 10 are used with the insulation. The holding frame 37 forms side contours of the cell modules 10 and thus secures them against displacement in the longitudinal direction 33 and the transverse direction 34 , After all cell modules 10 of the cell block 23 in the cell block holder with the holding frame 37 are used, the electrical series connection of the cell modules takes place 10 by the welding of the contact tongues 21 with the contact surfaces 20 the battery cells 12 of the respective adjacent cell module 10 , For fixing the cell modules 10 in the high direction 35 indicates the cell block 23 one on the support frame 37 attached clamping plate 38 on. The clamping plate 38 serves as a lid for the cell block 23 , Is the clamping plate 38 mounted, the cell block becomes 23 in the battery case 27 fixed, thereby simultaneously fixing the cell modules 10 in the high direction 35 down is made. The battery case 27 has a housing bottom, the inside of which is electrically insulated, for example with a glued-on plastic film. One between a bottom of the cell modules 10 and the insulating film remaining, tolerance-related gap is preferably filled with a thermally conductive potting compound, prior to installation of the cell block 23 was spread on the insulation film. The fluid-flow heat exchanger plate 30 is on the bottom of the battery case 27 attached and covered with an insulation plate to the outside. Through the external heat exchanger plate 30 a short circuit in the battery interior can be prevented by escaping cooling water, for example in a crash.

LIST OF REFERENCE NUMBERS

10

cell module

10

cell module

11

Motor vehicle battery

12

battery cell

12 '

battery cell

13

conductor rail

13 '

busbars

14

inside

15

inside

16

inside

17

inside

18

inside

19

contact area

20

contact area

20 '

contact surfaces

21

contact tongue

22

potting compound

23

cell block

24

electric motor

25

internal combustion engine

26

drive wheels

27

battery case

28

electronics

29

tempering

30

heat exchanger plate

31

cell case

32

lateral surface

33

longitudinal direction

34

transversely

35

vertical direction

36

foil blister

37

stop frame

38

clamp

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

• WO 2011/33727 A1 [0002]

Claims (10)

Cell module ( 10 ) for a motor vehicle battery ( 11 ), with a plurality of battery cells ( 12 ), and with a busbar ( 13 ), the battery cells ( 12 ) in an electrical parallel connection with each other, characterized in that the busbar ( 13 ) forms a cell holder which holds the battery cells ( 12 ) mechanically fixed in at least two directions. Cell module ( 10 ) according to claim 1, characterized in that the busbar ( 13 ) at least two differently oriented insides ( 14 . 15 . 16 . 17 . 18 ), through which the battery cells ( 12 ) are positively fixed and / or fixable in the at least two directions. Cell module ( 10 ) according to claim 2, characterized in that the inner sides ( 14 . 15 . 16 . 17 ) are at least partially opposite each other and the battery cells ( 12 ) between the insides ( 14 . 15 . 16 . 17 ) are arranged. Cell module ( 10 ) according to one of the preceding claims, characterized in that one of the insides ( 18 ) of the busbar ( 13 ) forms a bottom, which is used for electrical contacting of the battery cells ( 12 ) is provided. Cell module ( 10 ) according to claim 4, characterized in that each of the battery cells ( 12 ) an electrical contact surface ( 19 . 20 ) formed with the bottom ( 18 ) of the busbar ( 13 ) are firmly connected. Cell module ( 10 ) according to one of the preceding claims, characterized in that the busbar ( 13 ) a contact tongue ( 21 ), for the electrical contacting of battery cells ( 12 ' ) of a cell module ( 10 ' ) is provided. Cell module ( 10 ) according to claim 6, characterized by at least one electrical insulation, which is provided for electrical insulation with respect to an adjacently arranged cell module ( 10 ' ) is provided. Cell module ( 10 ) according to one of the preceding claims characterized by a potting compound ( 22 ) for fixing the battery cells ( 12 ), for which the busbar ( 13 ) at least partially serves as a casting mold. Cell block ( 23 ) for a motor vehicle battery ( 11 ), in particular a high-voltage battery, with at least two cell modules ( 10 ) according to any one of the preceding claims. Method for producing a cell module ( 10 ) according to one of claims 1 to 8, characterized in that the formed as a cell holder, integrally running busbar ( 13 ) is produced by means of a forming process.

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