WO2017194181A1

WO2017194181A1 - Cell module for a motor vehicle battery

Info

Publication number: WO2017194181A1
Application number: PCT/EP2017/000307
Authority: WO
Inventors: Stephan Lauckner; Jens Meintschel; Dirk Schroeter; Knut Welke; Danilo ZSCHECH
Original assignee: Daimler Ag
Priority date: 2016-05-13
Filing date: 2017-03-08
Publication date: 2017-11-16
Also published as: DE102016005967A1

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) that connects the battery cells (12) in a parallel electric circuit; the bus bar (13) forms a cell holder which mechanically secures the battery cells (12) in at least two directions. The invention also relates to a method for manufacturing a cell module (10) of said type.

Description

Cell module for a motor vehicle battery

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

From WO 201 1/33727 A1 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, is already known.

The invention is in particular the object of simplifying a structure and / or assembly of such a cell module. She is going through a

inventive design according to claim 1 and a

inventive method according to claim 10 solved. 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 the

Battery cells mechanically fixed 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 used for electrical contacting of the electrochemically active part are provided. 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 faces the battery cells in the assembled state 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" is to be understood as meaning, in particular, a part of the busbar which is provided for electrically contacting all battery cells of the adjacent cell module, whereby in the cell module a second contact rail, which is provided for this purpose, forms the further contact surfaces of the battery cells of the cell module Preferably, the cell module comprises only a single bus bar, which is provided to a pole of the cell module

train.

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. Under one

"Vergussmasse" should be understood in this context, in particular a mass, which after a fixation of the battery cells to the busbar in

Gaps between the battery cells and the busbar can be introduced and after curing the battery cells and the busbar non-positively and / or materially connects.

Next is a cell block for a motor vehicle battery, in particular a

High-voltage battery, proposed with at least two cell modules according to the invention. In addition, a method for producing a cell module according to the invention is proposed, in which the cell holder formed as one piece executed

Busbar 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 formed components are in the

Description of the figures 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 shows a motor vehicle with a motor vehicle battery,

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

Fig. 3 shows the cell module of Fig. 2 in a second view with an attached

Insulation,

4 shows the cell block with a plurality of cell modules and

5 shows a section through one of the cell modules.

FIGS. 1 to 5 show a motor vehicle with a motor vehicle battery 11. In the illustrated embodiment, the motor vehicle is a hybrid vehicle

educated. The motor vehicle comprises a drive train with an electric motor 24 and an internal combustion engine 25, both of which are provided for driving drive wheels 26. Alternatively, it is also conceivable that the motor vehicle as a

Electric vehicle is formed and the drive train only the electric motor 24th includes. It is also conceivable that the motor vehicle has a decentralized drive concept with a plurality of electric motors which are each provided directly for driving one of the drive wheels 26. The design of the motor vehicle battery 11 is independent of the intended drive concept. Basically, that can

Motor vehicle also have a differently shaped drive train. The

Motor vehicle battery 1 1 is designed as a high-voltage battery.

The motor vehicle battery 1 1 comprises a plurality of cell blocks 23. The cell blocks 23 comprise a plurality of battery cells 12 which are provided for storing and outputting the electric power. The cell blocks 23 and 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, wherein 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. In principle, however, the cell voltage can also have other values. The motor vehicle battery 1 1, 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. If the motor vehicle battery 11 is 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 formed as a high-voltage battery, the motor vehicle battery 11 is for a

Battery voltage of 90 volts or more, especially for a battery voltage of 120 volts, provided.

The motor vehicle battery 11 has a battery housing 27 which receives the cell blocks 23 with the battery cells 12. Furthermore, the motor vehicle battery 11 comprises electronics 28, which are provided in particular for monitoring the battery cells 12 and for setting an electrical power supplied to the battery cells 12 or taken from the battery cells 12. In addition, the includes

Motor vehicle battery 11 a tempering device 29 for the battery cells 12 and / or the electronics 28, which irisbesondere is provided for cooling and / or heating of the battery cells 12. The cell blocks 23 with the battery cells 12, the electronics 28 and the tempering device 29 are arranged in the common battery housing 27 (see FIG. The tempering device 29 comprises a heat exchanger plate 30, which is thermally in contact with the battery cells 12. The heat exchanger plate 30 has Channels, which are flowed through in one operation of a cooling water. The

Heat exchanger plate 30 can also be used to heat the cell modules 10.

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 housing 31 has a cell bottom and a cell lid, which form contact surfaces 19, 20 of the battery cell 12. At the contact surface 19, by the preferably at least substantially flat cell bottom

is formed, 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, for example, in case of short circuit or overcharge, in an electrolyte space

built-up pressure can be reduced. The cell housing 31 has a lateral surface 32, which may be coated for electrical insulation with a kind of shrink tubing made of 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 extension direction of the battery cell 12. The lateral surface 32 extends along the

Longitudinal direction between the contact surfaces 19, 20th

The battery cells 12 have a capacity which is typically less than 10 Ah. In order to be able to provide the cell block 23 with a higher capacity, the battery cells 12 are interconnected to cell modules 10. The battery cells 12 of a cell module 10 are connected together in an electrical parallel connection. The cell module 10 has a module voltage which corresponds 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 that depends on the module voltage and a number of the cell modules 10.

In order to connect the battery cells 12 in electrical parallel connection with each other, the cell module 10 comprises a bus bar 13 which is formed of an electrically conductive material. The busbar 13 is provided to connect the contact surfaces 19, 20 of all battery cells 12 of the cell module 10, which have a same polarity with each other. In addition, the busbar 13 is provided for the electrical interconnection with the adjacent cell module 10 '. The busbar 13 thus forms a pole of the cell module 10. In the illustrated embodiment, the Conductor rail 13 connected to the contact surfaces 19, 20 of the battery cells 12, which form the negative poles.

The busbar 13 forms a cell holder, the battery cells 12 in

mechanically fixed different directions. The busbar 13 is thus provided for the electrical and the mechanical connection of the battery cells 12. Trained as a cell holder busbar 13 has a plurality, the battery cells 12th

facing inner sides 14, 15, 16, 17, 18. Each of the inner sides 14, 15, 16, 17, 18 fixes the battery cells 12 positively in one direction.

The illustrated busbar 13 has the five in different directions

oriented inner sides 14, 15, 16, 17, 18. Through the five inner sides 14, 15, 16, 17, 18, the battery cells 12 are fixed positively in five directions. The busbar 13 is open only on one side. Due to the five inner sides 14, 15, 16, 17, 18, the bus bar 13 has a cup shape, from which the battery cells 12

be recorded. The two inner sides 14, 15 fix the battery cells 12 in the direction parallel to a longitudinal direction 33. The two inner sides 16, 17 fix the battery cells 12 in the direction parallel to a transverse direction 34. The fifth inner side 18 fixes the battery cells 12 in the direction parallel to a vertical direction 35th

Due to the cup shape, the four inner sides 14, 15, 16, 17 arranged in pairs opposite each other. The battery cells 12 are arranged between the four inner sides 14, 15, 16, 17. The four inner sides 14, 15, 16, 17 form one

Beaker wall off. The four insides 14, 15, 16, 17, 18 have

Surface normal, which are oriented substantially parallel to the longitudinal direction 33 and the transverse direction 34. The battery cells 12 are arranged side by side in the form of a stack for a densest ball packing. The inner sides 14, 15, 16, 17, which fix the battery cells 12 in the four directions, have a shape adapted to the stacking of the battery cells 12. In the illustrated embodiment, in which the battery cells 12 are formed as round cells, the inner sides 14, 15, 16, 17 are formed wave-shaped.

The fifth inner side 18 of the busbar 13 forms a bottom of the cup shape. The fifth inner side 18 is provided for electrically contacting the battery cells 12. The formed as a bottom inside 18 is substantially flat. The negative pole forming contact surface 20 of the battery cells 12 is fixed, preferably cohesively connected to the inside 18 of the busbar 13. In a production, the Battery cells 12 placed on the formed as a bottom inside 18 of the busbar 13 and then welded to the inside 18, for example by overlap laser welding, one-sided spot welding, laser soldering or another, the expert appears to be useful process.

The busbar 13 is integrally formed. The busbar 13 is preferably made of a metal or a metal alloy, such as in particular aluminum

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, it is also conceivable to assemble the busbar 13 from a plurality of components.

Preferably, at least that part of the busbar 13 which mechanically fixes the battery cells 12 is produced by a forming process of a blank. The

shown cell module 10 has a total of 29 round cells, which are connected to each other in an electrical parallel connection. The cell block 23 comprises six

Cell modules 10, which are connected to each other in an electrical series connection. The busbar 13 is made of deep-drawn copper sheet, wherein the bottom forming inside 18 in areas which is provided for connection to the contact surfaces 20 of the battery cells 12, is provided with indentations, which allow a play-free contact surfaces 20. The battery cells 12 are fixed to the busbar 13 by laser overlap welding. Additionally or alternatively, it is also conceivable to fix the battery cells 12 in a form-fitting manner, for example by the beaker wall formed by the inner sides 14, 5, 16, 17 being crimped inwards at an upper edge. In addition, the battery cells 12 can be connected by a bond to the busbar 13.

The cell module 10 has an electrical insulation which is provided for electrical insulation with respect to the adjacently arranged cell module 10 '. In particular, the insulation electrically separates the busbars 13, 13 'of the adjacent cell modules 10, 10' when the cell modules 10, 10 'in the cell block 23 are mechanically connected to one another. To form the insulation preferably thin plastic films or plates between the cell modules 10 are inserted or on the

Busbars 13 of the individual cell modules 10 postponed. Alternatively, it is also conceivable to glue the insulation on the conductor rail 13 or to coat the bus bar 13 on its outside with plastic. In the illustrated Embodiment, the insulation is formed by an over-pushed plastic foil blister 36.

Furthermore, the cell module 10 has a potting compound 22 which connects the battery cells 12 to the busbar 13 designed as a cell holder. The busbar 13 serves as a casting mold. In a production of the cell modules 10, the

Battery cells 12 initially connected to the busbar 13. Subsequently, cavities between the battery cells 12 and the inner sides 14, 15, 16, 17, 18 of the bus bar 13 are poured out. Due to the cup shape, the busbar 13 forms the mold for the potting compound.

In order to serve at least partially as a casting mold, the busbar 13, at least the inner side 18, which forms the bottom, and the inner side 17, to which the

Contact tongue 21 is connected. If the busbar 13 only a part of the illustrated inner sides 14, 15, 16, 17, 18, in a production, the cell module 10 is inserted into a mold, which limits the battery cells 12 in directions in which the busbar 13 is open. After curing the

Potting compound 22 has a cell module 10 thus produced on outer sides, which partially through the busbar 13 and partially through the potting compound 22nd

are formed. If the outside, which is opposite to the contact tongue 21, formed by the potting compound 22, can be dispensed with an additional insulation. In such a case, the potting compound 22 forms the electrical insulation, which is provided for electrical insulation with respect to the adjacently arranged cell module 10 ".

The potting compound 22 causes a thermal coupling of the battery cells 12 to the Stromleitschiene. In the illustrated embodiment, the battery cells 12 are arranged in two rows along the transverse direction 34. Each of the battery cells 12 thus has a similar thermal connection to the busbar 13. 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 made of plastic, in which the cell modules 10 are inserted 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 are inserted into the cell block holder with the holding frame 37, takes place

electrical series connection of the cell modules 10 by the welding of the

Contact tongues 21 with the contact surfaces 20 of the battery cells 12 of each

adjacent cell module 10. To fix the cell modules 10 in the vertical direction 35, the cell block 23 on the holding frame 37 patch clamp 38 on. The clamping plate 38 serves as a cover for the cell block 23. If the clamping plate 38 is mounted, the cell block 23 is fixed in the battery case 27, whereby at the same time

Fixing the cell modules 10 in the vertical direction 35 is made downward. The battery housing 27 has a housing bottom, the inside of which is electrically insulated, for example, with a glued-on plastic film. A tolerance-related gap remaining between an underside of the cell modules 10 and the insulation film is preferably filled up with a thermally conductive potting compound which has been applied to the insulation film before installation of the cell block 23. The fluid-flowed heat exchanger plate 30 is mounted on the underside of the battery case 27 and covered with an insulation plate to the outside. By the outside

Heat exchanger plate 30, a short circuit in the battery interior can be prevented by leaking cooling water, for example in a crash.

LIST OF REFERENCE NUMBERS

cell module

'Cell module

Power tool battery

battery cell

'Battery cell

conductor rail

'Busbars

inside

contact area

'Contact surfaces

contact tongue

potting compound

cell block

electric motor

internal combustion engine

drive wheels

battery case

electronics

tempering

heat exchanger plate

cell case

lateral surface

longitudinal direction

transversely

vertical direction

foil blister

stop frame

clamp

Claims

claims

Cell module (10) for a motor vehicle battery (1 1), with a plurality of

Battery cells (12), and having a bus bar (13) which connects the battery cells (12) in an electrical parallel circuit,

characterized in that

the busbar (13) forms a cell holder which mechanically fixes the battery cells (12) in at least two directions.

Cell module (10) according to claim 1,

characterized in that

the busbar (13) has at least two differently oriented inner sides (14, 15, 16, 17, 18), by means of 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 inner sides (14, 15, 16, 17) are arranged.

Cell module (10) according to one of the preceding claims,

characterized in that

one of the inner sides (18) of the busbar (13) forms a bottom, which is provided for electrical contacting of the battery cells (12).

5. Cell module (10) according to claim 4,

characterized in that

each of the battery cells (12) having an electrical contact surface (19, 20) which are fixedly connected to the bottom formed as the inner side (18) of the busbar (13).

6. cell module (10) according to any one of the preceding claims,

characterized in that

the busbar (13) has a contact tongue (21) which is provided for electrically contacting battery cells (12 ') of a cell module (10') arranged adjacently thereto.

7. cell module (10) according to claim 6,

marked by

at least one electrical insulation, which is provided for electrical insulation with respect to an adjacently arranged cell module (10 ').

8. cell module (10) according to any one of the preceding claims

marked by

a potting compound (22) for fixing the battery cells (12), for the

Busbar (13) at least partially serves as a casting mold.

9. cell block (23) for a motor vehicle battery (11), in particular a

High-voltage battery, with at least two cell modules (10) after one of

previous claims.

10. A method for producing a cell module (10) according to any one of claims 1 to 8, characterized in that

formed as a cell holder, integrally designed busbar (13) is produced by means of a forming process.