DE102011109208A1 - Battery e.g. lithium-ion battery has spacers for electrically insulating heat-conducting material are provided between cell stack and temperature control device - Google Patents

Abstract

The battery has several unit battery cells (2) which are directly or stacked together with the intermediate frame (5) to form a cell stack (1). A temperature control device (6) is mounted on one side of the cell stack. An electrically insulating material (10) is provided between the temperature control device and the cell stack. Several spacers are provided between cell stack and temperature control device, so that gap for electrically insulating heat-conducting material in set with small size.

Description

The invention relates to a battery of a plurality of individual battery cells according to the closer defined in the preamble of claim 9. The invention also relates to the use of such a battery.

Batteries are known from the general state of the art. In particular, so-called high-voltage batteries or high-performance batteries for vehicle applications, which are typically used as traction battery in at least partially electrically powered vehicles, typically consist of a plurality of battery cells, which are stacked to one or more cell stacks. The one cell stack or the plurality of cell stacks then form the overall battery, which can be embodied for example in lithium-ion technology. As a traction battery, it is also used for storing drive power in hybrid vehicles or electric vehicles, such as in vehicles powered by a combination of a fuel cell system and a battery with electric drive power. The battery cells are electrically connected in series and / or in parallel and are located with associated electronics and cooling typically in a common housing. The individual battery cells which are combined to form the cell stacks are mechanically connected to one another, for example, by pressure gauges and tie rods to the cell stack.

Now it is the case that the cell stacks from the battery cells typically require a predetermined operating temperature in order to be able to work ideally. This means that the cell stacks typically need to be cooled during normal operation. During commissioning, it may also be useful / necessary to heat them accordingly, in order to bring them to operating temperature as quickly as possible and thus be able to make very careful use of the batteries with regard to their service life. Each of the cell stacks therefore has a tempering device, which is often designed in the form of a cooling or heating plate, which is typically traversed by a fluid, such as water, air conditioning of an air conditioner, air or the like to dissipate waste heat. When the cell stack is very cold, it is heated accordingly by the medium flowing through the cooling plate. In addition, in the area of the cooling plates, in addition or as an alternative thereto, electrical heating or cooling elements, for example resistance heating elements, Peltier elements or the like, are also known.

In general, it is now the case that the tempering device is arranged on one side of the cell stack and either is in direct contact with the cell housing or the cell poles or is indirectly thermally coupled to the battery individual cells via intermediate frames, cell connectors, cooling plates or the like. To compensate for tolerances and in particular for the electrical insulation between the tempering device, which is generally metallic, and the battery individual cells or the components of the battery individual cells, an electrically insulating heat-conducting material is arranged between the tempering device and the stack of individual battery cells. This is typically designed as a heat-conducting foil or potting compound.

By way of example, the German Offenlegungsschrift DE 10 2009 035 461 A1 which shows an example of a cell stack of individual battery cells, in which a heat-conducting foil is arranged between the cell stack and a tempering device, which is designed here as a cooling plate.

Now, with the use of an electrically insulating thermally conductive material, the thermal conductivity typically decreases with the thickness of the material. It is therefore desirable as thin a material as possible. On the other hand, it must be prevented that the material is damaged in the assembly or in a possible force on the cell stack, for example in a carelessness during installation or in an accident to prevent a short circuit of the battery cells by the temperature control in each case. Therefore, the electrically insulating thermally conductive materials are typically made thicker in practice than is technically necessary. However, this means that a correspondingly greater cooling power or heating power must be applied in the region of the tempering device for exact temperature control of the cell stack. This is energy intensive and degrades the efficiency of the battery. In addition, the construction becomes more expensive and heavier than necessary.

The object of the present invention is now to provide a battery with a plurality of individual battery cells, which circumvents this problem and can be constructed compact and energy-efficient.

According to the invention this object is achieved by the features in the characterizing part of patent claim 1. Further advantageous embodiments of the battery according to the invention will become apparent from the dependent therefrom dependent claims.

In the battery according to the invention it is provided that between the cell stack and the tempering are arranged spacers, which ensures a minimum of a gap for the electrically insulating heat-conducting material. Such spacers define a minimum dimension for the gap, in which the electrically insulating heat-conducting material is arranged, by means of mechanical striking. Thus, this minimum dimension between the tempering device and the cell stack is always ensured both during assembly and in the subsequent handling of the cell stack. The electrically insulating heat-conductive material therein is thus not further compressed than predetermined by the spacers. For a very safe and reliable construction is achieved, which allows the use of a correspondingly thin electrically insulating thermally conductive material, without this being so far compressed during assembly and / or handling of the cell stack, thereby causing damage to the electrically insulating heat-conducting material , which then leads to a malfunction of the cell stack.

By using the spacers to maintain a minimum gap of the electrically insulating material can thus be very simple and efficient to achieve a structure which both during assembly and during handling of the cell stack and force effects, such as due to a collision or the like can occur when used in a vehicle, works safely and reliably. In addition, the electrically insulating heat-conducting material can be made correspondingly thinner so that the temperature of the battery cells of the cell stack can be made much more energy efficient. Nevertheless, an electrically insulating distance is ensured even under mechanical or thermal overload due to the spacers in each case.

The construction of the battery thus becomes very energy efficient, compact and safe.

According to a particularly advantageous embodiment of the battery according to the invention, the spacers may be formed integrally with the tempering device. This structure allows a very simple and efficient handling, since during assembly, the tempering must be mounted only on the cell stack after a heat-conducting foil has been applied or a potting compound has been painted. The spacers integrated in the tempering device then ensure that the minimum gap dimension is maintained in any case and the heat-conducting foil is not excessively pressed too much or the sprayed-on potting compound is fixed in exactly the thickness in which this is necessary and sensible.

In a supplementary or alternative embodiment thereof, it may of course also be possible for the spacers to be formed integrally with parts of the battery individual cells or of the cell stack. The functionality is essentially the same. In principle, it is of course also possible to form the spacers in one piece in part in the region of the tempering device and partly in the region of the individual battery cells or of the cell stack.

The battery of the invention allows in the described embodiment a simple, fast and safe construction and allows a very energy-efficient operation. It may in particular be designed as a lithium-ion battery and may preferably be used as a traction battery in an at least partially electrically driven vehicle. Particularly in the case of at least partially electrically driven vehicles, a simple and efficient construction of the battery during assembly is of crucial importance due to the high expected number of units. In addition, when installing the battery in the vehicle, a high safety standard must be met, which is ensured by the spacer according to the invention to the effect that no short circuit of the battery individual cells can be done via the temperature control device even with rough shocks in the assembly.

Also with regard to a mechanical or thermal overload, for example, by an accident or fire on board the vehicle, the inventively constructed battery in the area between the tempering and the cell stack can run very safe. The battery according to the invention is thus particularly well suited for use in a vehicle.

Further advantageous embodiments of the battery according to the invention will become apparent from the remaining dependent claims and will be apparent from the embodiment, which will be described below with reference to the figures.

Showing:

1 a cell stack battery in a first embodiment;

2 the cell stack the 1 in an exploded view;

3 a section of the cell stack according to 1 in an exploded view;

4 the section of the cell stack according to 3 in assembled condition;

5 a cross section through the cell stack according to 1 in an exploded view;

6 a cross section through the cell stack according to 1 in assembled condition;

7 a cross section through the cell stack according to 1 in the assembled state in a first alternative embodiment;

8th a cross section through the cell stack according to 1 in the assembled state in a second alternative embodiment;

9 a cell stack in a second embodiment;

10 a cell stack according to 9 in an exploded view;

11 Section through the cell stack according to 9 in a first sectional plane;

12 Section through the cell stack according to 9 in an exploded view in a second sectional plane;

13 Section through the cell stack according to 9 in the second cutting plane in the assembled state;

14 a cell stack in a third embodiment;

15 a cell stack according to 14 in an exploded view;

16 Sectional view through the cell stack according to 14 ; and

17 a three-dimensional representation of an intermediate frame of the cell stack according to 14 ,

In the presentation of the 1 is a cell stack 1 to recognize in a first embodiment. It consists of a large number of individual battery cells 2 leading to the cell stack 1 piled up and between two pressure goggles 3 with tie rods 4 to the cell stack 1 are performed braced. The battery cells 2 are in the presentation of 1 not recognizable, as they are from intermediate frames 5 to be covered. In the exploded view of the 2 are the intermediate frames 5 and some of the battery cells 2 however, to recognize explicitly. In the presentation of the 1 At the top of the cell stack are two tempering devices 6 , here in the form of two cooling plates 6 which have connections 7 be traversed by a liquid and / or vaporous cooling medium to recognize. About the tempering devices 6 lets the cell stack 1 during normal operation, for example when starting the cell stack 1 , especially at low ambient temperatures, can be via the tempering 6 and a corresponding "cooling medium" which is warmer than the battery cells 2 of the cell stack 1 is, also a warming of the cell stack 1 make.

As can be seen from the following illustrations, the tempering devices are 6 in thermal contact with cell connectors 8th through which electrodes 9 the battery cells 2 electrically connected to each other. About the cell connectors 8th so become the electrodes 9 the battery cells and thus the battery cells 2 in itself by the tempering 6 heated accordingly and in particular cooled. As the tempering 6 Typically formed of metallic, good heat conducting material, these would be in direct contact with the cell connectors 8th the battery cells 2 Short circuit accordingly, which of course should not happen. Therefore, between the tempering 6 and the battery cells 2 of the cell stack 1 or the cell connectors 8th an electrically insulating heat conducting foil 10 arranged, which has a thermally conductive contact between the cell connectors 8th and the tempering 6 allows these electrically but isolated from each other. Instead of the electrically insulating heat conducting foil 10 would also be an electrically insulating, but thermally conductive potting conceivable, which in a thin layer, in particular to the tempering 6 is applied, and hardens after assembly.

In the presentation of the 3 is an enlarged view of two battery cells 2 and the intermediate frame arranged between them 5 to recognize. There is also a cell connector 8th shown. In 4 is the in 3 to recognize assembly shown in exploded view then assembled. The cell connector 8th is with the electrodes 9 the two adjacent battery cells 2 appropriately connected, for example by ultrasonic welding or the like. The other electrodes 9 the battery cells 2 are not connected, but with each on the other side adjacent battery cells 2 connected so within the cell stack 1 a series connection of the battery individual cells 2 arises.

On the in the cell stack 1 then each spaced apart cell connectors 8th in each case the in 2 heat-conducting foil to be recognized 10 applied, then the temperature control 6 with the cell stack 1 screwed. This is in the sectional views of 5 and 6 shown again, where 5 the condition before the assembly and 6 shows the state after the successful installation. Now it is so that the heat-conducting foil 10 to achieve a good thermal connection between the tempering 6 and the cell connector 8th about in the 5 and 6 shown screws 11 as fasteners or clamping means on the cell connector 8th is pressed. During assembly, there is a risk that the thin and mechanically comparatively sensitive heat-conducting foil 10 Inadmissible pressed and thereby crushed. This can lead to electrical contact of the current-carrying cell connector 8th and the metallic tempering device 6 to lead. A short circuit of the battery individual cells 2 would be the result. Comparable problems can also be seen later on the cell stack 1 occurring shocks, for example during assembly of the cell stack 1 in a vehicle or even in an accident of the vehicle occur. To prevent this, now are spacers 12 intended. These spacers 12 are in the 3 to 6 each as a hump-like one-piece with the intermediate frame 5 recognize trained elements. They provide a defined gap between the cell connector 8th and the tempering device 6 In any case, make sure the heat-conducting foil 10 during assembly and in subsequent force effects not on dimensions below this gap defined, which in the representation of the 5 located and designated S, can be pressed.

This creates a very secure structure. It also makes it possible to use comparatively thin heat-conducting foils 10 because of the spacers 12 on big additional safety in the thickness of the heat conducting foil 10 can be waived. This is the heat-conducting foil 10 thinner and the thermal connection of the tempering 6 to the battery cells 2 better. The energy efficiency of the battery is thereby improved.

An alternative embodiment of the spacers 12 is in the representation of 7 to recognize which in their construction essentially the representation in 6 equivalent. Instead of the one-piece design of the spacers 12 with the intermediate frame 5 of the cell stack 1 It is provided here that the spacers 12 integral with the tempering device 6 are executed.

In the presentation of the 8th is another alternative embodiment analogous to the illustrations in FIGS 6 and 7 to recognize, in which the spacers 12 are designed as independent elements. The spacers 12 must be incorporated in this construction during assembly with.

In the presentation of the 9 is an alternative embodiment of the cell stack 1 to recognize. Instead of two tempering devices 6 Here is only a tempering 6 provided on the underside of the cell stack 1 is appropriate. It is in turn about a variety of screws 11 and one between the tempering device 6 and the cell stack 1 arranged Wärmeleitfolie 10 electrically isolated, but thermally conductive with the cell stack 1 connected. Otherwise applies to the structure of the cell stack 1 essentially the one already said, also here are corresponding intermediate frames 5 between the battery cells 2 provided and over pressure goggles 3 is the cell stack 1 by tie rods 4 braced. Instead of cell connectors 8th Here is a cell connector board 13 intended.

In the sectional view of 11 is a section plane in the middle of an intermediate frame 5 shown in a section. The mounted state of the tempering device 6 shows the electrically insulating heat conducting foil 10 which is a certain distance to the intermediate frame 5 having. in the presentation of the 12 , a comparable section of a sectional plane through the middle of a single battery cell 2 before assembly, the structure can be seen again. The spacers 12 are in this case integral with the intermediate frame 5 trained and leave so the turn designated S defined gap. The single battery cell 2 protrudes slightly above the lower edge of the intermediate frame 5 in the sectional plane as shown in FIG 11 out so that the heat-conducting foil 9 safe and reliable with the single battery cell 2 and not with the intermediate frame 5 comes in contact. This is also a certain tolerance compensation between the dimensions of the battery individual cells 2 possible. In the presentation of the 13 is then the assembled state to recognize, in which by the spacers 12 a defined minimum of the gap between the battery cells 2 and the tempering device 6 in which the heat-conducting foil 10 is arranged, guaranteed in every situation.

Another alternative embodiment of a cell stack 1 is in the representation of 14 to recognize. This corresponds essentially to that in the illustration of 9 already described construction. Instead of tie rods 4 assume here two tempering 6 However, a double function in the way that they form both the tempering and take over the functionality of the tie rods with. This is realized in such a way that the temperature control devices rest laterally and over in the exploded view of FIG 15 better recognizable screws 14 with the pressure goggles 3 are performed braced. Otherwise, the structure corresponds to the representation of the cell stack 1 according to 9 ,

In the presentation of the 16 is again a sectional view of the cell stack 1 according to 9 through the middle of a single battery cell 2 analogous to the representation in 13 to recognize. Again, the spacers 12 in the intermediate frame 5 integrated and provide a defined gap for the electrically insulating Wärmeleitfolie 10 or a potting compound introduced in their place safely.

In the presentation of the 17 is in a three-dimensional representation of the intermediate frame 5 again shown individually. Very good is the spacer 12 in the form of a stage in the for the tempering 6 to recognize the intended recess.

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 102009035461 A1 [0005]

Claims (10)

Battery from a large number of individual battery cells ( 2 ), which directly or together with intermediate frames ( 5 ) to a cell stack ( 1 ) are stacked on at least one side of the cell stack ( 1 ) a tempering device ( 6 ), and wherein between the tempering device ( 6 ) and the cell stack ( 1 ) an electrically insulating material ( 10 ), characterized in that between the cell stack ( 1 ) and the tempering device ( 6 ) Spacers ( 12 ) are arranged, through which a minimum of a gap (S) for the electrically insulating heat-conducting material ( 10 ) is guaranteed. Battery according to claim 1, characterized in that the spacers ( 12 ) in the area of fasteners ( 11 ) for fixing the tempering device ( 6 ) on the cell stack ( 1 ) are arranged. Battery according to claim 1 or 2, characterized in that the electrically insulating heat-conducting material ( 10 ) is designed as a heat conducting foil. Battery according to claim 1 or 2, characterized in that the electrically insulating heat-conducting material ( 10 ) is designed as potting compound. Battery according to one of claims 1 to 4, characterized in that the spacers ( 12 ) at least partially in one piece with the tempering device ( 6 ) are formed. Battery according to one of claims 1 to 5, characterized in that the spacers ( 12 ) at least partially integral with parts of the single battery cell ( 2 ) or the cell stack ( 1 ) are formed. Battery according to claim 6, characterized in that the battery cells ( 2 ) together with intermediate frames ( 5 ) to the cell stack ( 1 ) are stacked, the spacers ( 12 ) at least partially integral with the intermediate frames ( 5 ) are formed. Battery according to one of claims 1 to 7, characterized in that the tempering device ( 6 ) is formed as flowed through by a liquid and / or vapor medium plate. Battery according to one of claims 1 to 8, characterized in that the tempering device ( 6 ) has electrical heating elements and / or electrical cooling elements. Use of a battery according to one of claims 1 to 8 as a traction battery in an at least partially electrically driven vehicle.

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