DE102010012998A1 - Battery e.g. lithium ion battery, for storing traction energy in e.g. electric propelled car, has battery single cells comprising intermediate member whose surfaces correspondingly form recesses on surfaces of battery single cells - Google Patents

Abstract

The battery (1) has battery single cells (2) i.e. coffee bag type cells, whose stack (3) is formed as self-contained flat cells, where the stack of the battery single cell is alternatively stacked with an intermediate member. Surfaces of the member of the battery single cells correspondingly form recesses on the surfaces of the battery single cells. The cells are formed, so that electrochemical active materials are welded into a film. The recess is formed, so that an edge area of the intermediate member lies beside the recess without contacting the respective cell in stacking direction.

Description

The invention relates to a battery with a stack of battery cells according to the closer defined in the preamble of claim 1.

As batteries, in particular as high-performance batteries for storing traction energy in an at least partially electrically driven vehicle batteries with stacks of battery cells are known. The individual battery cells may preferably be formed in lithium-ion technology. A typical design for such battery cells is the so-called flat cell, which is essentially flat and has the shape of a cuboid. Such flat cells are then stacked into a stack of battery cells. The battery itself is now formed by one or more such stacks, which are also referred to as module. For example, reference is made to the battery, which by the US 5,756,227 is described.

In the flat cells, which are very often used as battery cells for lithium-ion batteries, two different types are common. One type is a so-called frame flat cell, in which a stable frame two cover elements spaced from each other. The interior forming space is then filled with the electrochemically active material, typically a stack of anode foils, cathode foils, separators, and electrolyte. As an alternative, cells are conceivable which have a housing throughout, which is formed for example as a cuboid cavity, as can be seen in the above-mentioned US-Script. A much simpler and less expensive variant of this is a battery single cell, which is constructed so that the electrochemically active materials are formed in a shrink-wrapped film. The film then forms a kind of bag around the electrochemically active part of the single battery cell. The poles of the two electrical connections of the single battery cell, protrude from this welded bag typically on one side. Due to the bag shape, the single battery cell thus constructed is also referred to as a pouch or coffee bag cell.

The problem with stacking such trained as Pouch- or Coffeebag cells battery cells now lies in the fact that they move very easily against each other and thus are already relatively expensive during stacking and assembly. Even if the stacking is done and the stack is present, for example, strained by tension bands, tie rods or the like, the cells can continue to move transversely to the stacking direction against each other, for example, if there is an expansion of the cells due to different states of charge.

Even in the preferred use of the battery as a battery in an electric or hybrid vehicle, vibrations or the like can cause situations in which the stability of the stack from the battery individual cells is jeopardized. This is especially true when the vehicle equipped with the battery is involved in an accident. In the then occurring accelerations on the battery, for example, in a collision of vehicles, the stability of the stack of battery cells may be at great risk. If the battery individual cells are now formed in lithium-ion technology, care must also be taken, in order to meet dangerous goods regulations, to prevent such instability of the stack of individual battery cells. For example, if the shells of the battery individual cells are injured, the battery poses a considerable risk. The contact between lithium and the water used, for example, for cooling could lead to violent chemical reactions.

It is now the object of the present invention to avoid the disadvantages mentioned above and to provide a structure for a battery, which allows a very simple and reliable installation, and which also ensures high security for the battery.

According to the invention this object is achieved by the features mentioned in the characterizing part of claim 1.

Characterized in that the stack is stacked alternately from battery individual cells and at least one intermediate element, wherein the intermediate element on its / the battery single cell / n facing surface has a corresponding to the surface of the battery single cell shape, there is a safe and reliable investment of Single battery cell in the area of this corresponding shape. Thus, the single battery cell is held securely and reliably transversely to the stacking direction in the corresponding shape of the intermediate element. The intermediate element can be designed as a very simple and lightweight intermediate element, for example made of a plastic, a fiber-reinforced plastic or the like. Alternatively, it would also be conceivable to produce the intermediate element from a metallic material, which has as a corresponding shape, for example, deep drawing introduced depression or the like. Again, this would fulfill the functionality and could also take over other functionalities, such as a thermal or electrical line, with.

In a further particularly advantageous embodiment of the battery according to the invention, it is provided that between each two of the battery individual cells exactly one intermediate element is arranged, which has on each of its individual battery cells facing surfaces corresponding to each battery single cell shape. This structure with a single intermediate element, which is designed for example as a kind of double trough, between two adjacent battery individual cells can ensure a secure stacking of the battery individual cells with a minimum number of components.

If, for example, the corresponding shape is formed as a depression, then, according to a very favorable and advantageous development of the invention, it is designed such that the edge region of the intermediate element lying next to the depression does not touch the respective single battery cell. The corresponding recess thus receives the single battery cell, without being so deep that the single battery cell touches the intermediate element in the edge regions. This can be ensured that a frictional contact between the edge region and the battery single cell, which is designed for example as a sealed-in foil pouch cell, is prevented. Thus, the film can not be rubbed or damaged even with vibrations, such as those that occur in motor vehicles, for example, and no electrolyte can escape or the vacuum of the single battery cell can be destroyed.

Furthermore, according to a particularly advantageous development of the construction according to the invention, it can be provided that at least some of the intermediate elements have elastic elements in the region of their regions lying between the battery individual cells. These elastic elements, which protrude in a particularly favorable development of this idea transverse to the stacking direction on at least two sides over the stack of battery cells, can be used as damping elements. Thus, any shocks experienced by the stack of battery cells, taken over these elastic elements and can be cushioned or damped in these. This prevents hard impacts on the stack, especially in the event of a crash. Damage to the individual battery cells or the stack of individual battery cells can be avoided or at least minimized.

In a particularly favorable and advantageous development of this idea, it is also provided that the stack of battery cells is arranged in a housing, wherein the elastic elements rest in the installed state of the stack to the housing. The elastic elements thus carry the stack relative to the housing. This system can be done under a certain bias according to a very advantageous development. The stack is therefore safe and easy in the housing of the battery without any further elements. Nevertheless, it is decoupled from the housing of the battery by the elastic elements, so that not all vibrations, shocks, impacts and the like from the housing strike the stack with full hardness on the stack. This also serves the security of the stack, for example, in the event of a crash and can protect the stack in normal operation of a load caused by vibration.

In a very favorable and advantageous development of the battery according to the invention, it is also provided that the intermediate elements are at least partially formed of metal and connected in the metallic areas with the corresponding poles of the two adjacent battery individual cells. In this way, a corresponding contacting of the adjacent individual battery cells can be achieved via the intermediate elements or via the metallic regions in the intermediate elements, so that they can be interconnected, for example, in series with one another. This makes it possible to avoid expensive structures for contacting the electrical poles of the individual battery cells.

In a very favorable and advantageous development of this idea, it is provided that the intermediate element between two adjacent battery cells with a separation transverse to the stacking direction is constructed in two parts of metal, each part of the intermediate element is connected to one pole of the battery cell adjacent to the part. This construction with two-part intermediate elements thus provides that, for example, during the assembly of the individual battery cells, it is provided on each of its flat sides with a part of the intermediate element which is connected to one of the poles of the single battery cell. If this construction of individual battery cells and two parts of an intermediate element is then stacked, the two parts of the intermediate element come into contact with one another and form the two-part intermediate element arranged between two adjacent individual battery cells. At the same time, this contact represents the electrical contact between the single battery cell and the other single battery cell. By simply stacking these assemblies on each other, it is therefore possible to contact the battery individual cells. The stack is automatically connected in series with appropriate stacking direction, so that on one side of the stack of a pole and on the side of the stack of the other pole is applied. This is relatively simple and inexpensive, since during assembly, the electrical contact is formed automatically, without the need for additional installation effort would be necessary.

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 is explained below with reference to the figures.

Showing:

1 a plan view of an exemplary battery;

2 a three-dimensional representation of a single battery cell;

3 a representation of two battery cells with an intermediate element;

4 a representation of 3 on average;

5 a sectional view of the intermediate element with an elastic element;

6 a cross section through the stack of battery cells in a housing; and

7 an alternative embodiment of the intermediate element.

In 1 is a possible construction of a battery 1 shown in principle. The battery 1 consists of a large number of individual battery cells 2 of which only a few are provided with a reference numeral here. The battery cells 2 are formed as so-called flat cells and a stack 3 of battery cells 2 piled up. This pile 3 the battery cells 2 is electrically contacted in a manner explained in more detail later and can, in particular in an embodiment of the individual battery cells 2 in lithium-ion technology, have a suitable, known per se cooling. The stack 3 the battery cells 2 is between two end plates 4 over clamping devices 5 braced. The clamping devices 5 can be formed in any manner, are particularly common in such batteries 1 Tension bands, tie rods or the like for clamping the two end plates 4 , In the chosen representation of the 1 are the clamping devices 5 designed as a tie rod, which with the end plates 4 are connected by screwing. Now it comes when charging and discharging the battery cells to a variation of their volume depending on the state of charge. This volume change, referred to as "breathing," may well be on the order of about 0.1-0.4 mm in conventional flat cells in lithium-ion technology, which for example have a thickness in the stacking direction of about 10-15 mm. Will the battery 1 now used for storing traction energy in an electric vehicle, a hybrid vehicle, a fuel cell vehicle or the like, so are correspondingly high voltages of the battery 1 necessary. The number of battery cells 2 is therefore correspondingly high, in general, certainly much higher than in the exemplary representation of 1 , An extension of each individual battery cell 2 in the stacking direction by, for example, 0.2-0.3 mm thus leads overall to a significant length expansion or length shortening of the stack 3 , depending on the state of charge of the battery 1 , The in the presentation of the 1 tensioning devices designed as tie rods 5 Therefore, have a resilient element to compensate for such length expansion. This element 6 , which is an elasticity of the clamping devices 5 ensured in the stacking direction, ensures even pressure on the battery individual cells 2 of the pile 3 , regardless of the state of charge.

In the presentation of the 2 is one of the battery single cells 2 to recognize in a three-dimensional representation. It is a single battery cell 2 whose electrochemically active materials are welded between films in the manner of a bag. Battery cells 2 This type are also referred to as Pouch or Coffeebag cells. The electrochemically active materials, which are not visible here, generally consist of a stack of anode foils, cathode foils and separators arranged therebetween. This stack is soaked in electrolyte and sealed between the films or in a bag and sealed, typically under vacuum. On one side of the battery single cell 2 protrude two electric poles 7 . 8th out of the bag. This construction of single battery cell 2 is so far known and customary.

In the presentation of the 3 is one between two battery cells 2 introduced intermediate element 9 to recognize. The intermediate element 9 has at its two the battery cells 2 facing surfaces on a shape which corresponds approximately to the shape of the battery cells. In the embodiment shown here, this corresponding shape is designed in the manner of a depression, so that the intermediate element 9 in the direction of the respective single battery cell 2 trough-shaped opens. In the sectional view of 4 this can be seen again. The intermediate element 9 It has a substantially T-shaped cross-section and thus consists of two back-to-back troughs, which the battery cells 2 record accordingly. The battery cells 2 are thus fixed in all directions across the stacking direction in the tubs and are held with a slight clearance or preferably form-fitting. In the sectional view of 4 It can also be seen that the Depressions in the intermediate elements 9 are formed so that the edge areas lying next to the depression 10 in the stacking direction of the battery individual cells 2 not to the surface of the respective single battery cell 2 pass. This will ensure that the battery cells 2 only in the recesses of the intermediate elements 9 are held accordingly while their edge areas 10 are arranged at a certain distance from the battery individual cells. This allows the edge areas 10 of the intermediate element 9 the surface of the single cell battery 2 and so that the film in which it is welded, do not touch. Thus, it can not, for example, by vibrations, as they can occur when used in a vehicle, to a chafing of the film by the edge regions 10 come. This ensures a safe construction, in which the tightness of the individual battery cell 2 is safe. In addition to the holder of the battery individual cells 2 in the depression in the intermediate elements 9 , the battery can single cell 2 also with a flexible adhesive with the intermediate element 9 glued to an even safer construction of the stack 3 to ensure.

In the presentation of the 5 is now a section of two of the battery single cells 2 with the intermediate element 9 or its edge area 10 at one end of the battery cells 2 to recognize. The border area 10 is designed so that it has an approximately arcuate contour. In this arcuate contour is an elastic element in the embodiment shown here 11 arranged. This elastic element 11 may be formed, for example, as a rubber element with a circular or oval cross-section or as a hose, hollow chamber profile or the like. In particular, it may be in the nature of an O-ring around the entire edge area 10 of the intermediate element 9 be laid around. The elastic element 11 towers over, as in the presentation of 5 it can be seen, the battery individual cells in particular in the region of the projecting welds of the films. The structure can be designed so that the elastic element 11 the battery cells 2 Transversely to the stacking direction on at least two, in particular three sides surmounted accordingly. As from the representation of 3 It can be seen in the field of electric poles 7 . 8th such a structure rather not be possible, since this would require a correspondingly thick material, which would then adversely affect the electrical contact of the battery cells. Assuming, however, that by an appropriate material on the bottom and the two sides of the elastic element 11 the stack 3 the battery cells 2 surmounted accordingly, such a structure, for example, if he on a certain number of evenly distributed intermediate elements 9 in the pile 3 or on all of the intermediate elements 9 in the pile 3 is arranged, the stack 3 support the battery individual cells elastic. This elastic support over the elements 11 For example, in an in 6 illustrated housing 100 the battery 1 respectively. The stack 3 the battery cells 2 So it can be mounted and in the case of the battery 1 be introduced. Waiving further fasteners, the attachment then takes place in that the elastic elements 11 with a certain bias on the housing 100 to come to rest and the pile 3 the battery cells 2 Hold on like that. 6 is this integration of at least some elastic elements 11 provided stack 3 in single battery cells 2 in the case 100 indicated in principle in a cross section. It can be seen that the elastic element 11 in the embodiment shown here on three sides about the battery single cell 2 hierausragt. Will this construction of the stack 3 now in the in this embodiment in cross-section U-shaped housing 100 introduced, so are the elastic elements 11 at least on the sides where they are between the intermediate elements 9 and the housing 100 are arranged, biased accordingly and thus hold the pile 3 safe in the case 100 ,

By the elastic elements 11 can also be achieved that vibrations and vibrations are damped, so that the stack 3 to individual battery cells 2 this is not directly exposed. This can play a decisive role, especially when used in vehicles. Even stronger punches, such as those in the event of a crash with the battery 1 equipped vehicle can occur through the elastic elements 11 at least to a certain extent be damped, so the battery 1 at a corresponding load, for example, in the event of a crash, greater safety than a conventional battery.

The intermediate elements 9 can be formed in a preferred manner from a plastic material, only the secure mounting of the battery individual cells 2 and to ensure their fixation among each other. From a corresponding plastic material or a fiber-reinforced plastic, the intermediate elements 9 Do not add any significant weight to the structure of the battery. This creates a very light, easy to install construction of a stack 3 to individual battery cells 2 ,

However, it is also conceivable, the intermediate elements 9 from a metallic material form or plastic and form by metallic elements, for example, in the material incorporated copper bands or the like, an electrical conductivity sure. If such electrical conductivity of the intermediate elements 9 is present, this can be used selectively by adding parts of the intermediate elements 9 with the respective poles of the adjacent battery cells 2 be connected and so the stack 3 to individual battery cells 2 electrically contact, for example, a series connection of the individual battery cells 2 enable.

This is exemplary in one embodiment of the intermediate elements 9 in the presentation of the 7 indicated. In the embodiment shown here, the intermediate element 9 from two parts 9.1 and 9.2 built up. Each of the parts 9.1 and 9.2 is intended to be constructed of a metallic material, for example aluminum, copper or suitable alloys with at least one of these elements. In particular, a copper-beryllium alloy can be used.

The metallic parts 9.1 and 9.2 of the intermediate element 9 For example, by bending or deep drawing are formed so that in the area in which they are connected to the battery cells 2 abut, to the battery cells 2 corresponding areas, in this case corresponding wells train. In the in the presentation of the 6 The area shown below is also an elastic element 11 at the edge 10 of the intermediate element 9 to recognize. For the elastic element 11 , which is formed in this case as an annular cross-section hollow profile, the just described applies. This elastic element 11 can in particular on three sides of the intermediate element 9 be arranged.

At the electric poles 7 . 8th the battery individual cells facing side are the intermediate elements 9 over the edge area 10 also with one contact area each 12 Mistake. This contact area 12 , which is transverse to the stacking direction of the battery cells 2 over the areal extent of the intermediate element 9 extends, is made for example by folding or the like. It has the shape of at least one double shaft, so that it allows for a certain flexibility with corresponding changes in the thickness of the battery individual cells, which may occur, for example, by different charging and discharging states. This contact area 12 is now each with one of the poles of the adjacent battery cells 2 connected. The part 9.2 is with his contact area 12 with the negative pole 8th the right single battery cell in the illustration 2 connected while the contact area 12 of the part 9.1 of the intermediate element 9 with the positive pole 7 the other single battery cell 2 connected is. By doing that, the two parts 9.1 and 9.2 are arranged at least in the area of their substantially planar training "back-to-back", it comes through the contact to contact the two parts 9.1 and 9.2 of the intermediate element 9 , These therefore connect the positive electrical pole 7 the one battery cell 2 with the electric negative pole 8th the other single battery cell 2 , Is now on each side of each of the individual battery cells 2 one of the parts 9.2 and 9.1 the later intermediate elements 9 arranged, so can the battery individual cells 2 by simply stacking up when building the stack 3 electrically contacted and connected in series with each other. About the intermediate element 9 then both the fixation is made possible across the stacking direction and the electrical interconnection. On further electrical contacts can then be dispensed with. This ensures a very simple and efficient construction of the battery 1 ,

The connection between the contact area 12 and the poles 7 . 8th can be done by a terminal, in which, for example, the contact area 12 in the area where he has the electric pole 7 or 8th touched, screwed with this. This can be done for example by holes and inserted screws, but also by screwing with a corresponding flat profile, U-profile, L-profile or the like. Alternatively, it is also conceivable, the respective electrical pole 7 or 8th and the contact area 12 connect by welding together. Here, for example, ultrasonic welding, laser welding or seam welding as preferred options should be mentioned. In addition to the welding of course, a soldering, for example, a Ultraschalltotung or Hochfrequenzlötung conceivable. Alternatively, a mechanical joining can be considered, for example by grimping or squeezing. Also, the squeezing of clamping elements or analogous to the above-mentioned fitting the attachment of rivets, would be conceivable.

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

• US 5756227 [0002]

Claims (17)

Battery comprising a stack of individual battery cells, which are formed as self-contained flat cells, wherein the stack is alternately stacked of battery individual cells and in each case at least one intermediate element, characterized in that the intermediate element ( 9 ) on his / her battery cell (s) ( 2 ) surfaces facing one with the surface of the battery cell ( 2 ) has corresponding shape. Battery according to claim 1, characterized in that the corresponding shape is formed as at least one recess. Battery according to claim 1 or 2, characterized in that each of the individual battery cells ( 2 ) is formed so that the electrochemically active materials are sealed in foil. Battery according to one of claims 1 to 3, characterized in that between each two of the battery individual cells ( 2 ) exactly one intermediate element ( 9 ) arranged on each of its individual battery cells ( 2 ) facing surfaces to the battery single cell ( 2 ) has corresponding shape. Battery according to claim 4, characterized in that the intermediate element ( 9 ) has a substantially T-shaped in cross-section. Battery according to one of claims 2 to 5, characterized in that the recess is formed so that the lying adjacent to the recess edge region ( 10 ) of the intermediate element ( 9 ) the respective battery single cell ( 2 ) not touched in the stacking direction. Battery according to one of claims 1 to 6, characterized in that the battery individual cells ( 2 ) with the intermediate elements ( 9 ) are glued. Battery according to one of claims 1 to 7, characterized in that at least some of the intermediate elements in the region of their adjacent to the recesses edge regions ( 10 ) elastic elements ( 11 ) exhibit. Battery according to claim 8, characterized in that the elastic elements ( 9 ) across the stacking direction on at least two sides over the stack ( 3 ) of the battery individual cells ( 2 ) protrude. Battery according to claim 8 or 9, characterized in that the elastic elements ( 9 ) around the intermediate elements ( 9 ) are formed. Battery according to claim 8, 9 or 10, characterized in that the intermediate elements ( 9 ) at the edge ( 10 ) have a groove in which the elastic elements ( 11 ) are arranged. Battery according to one of claims 8 to 11, characterized in that the stack ( 3 ) of the battery individual cells ( 2 ) is arranged in a housing, wherein the elastic elements ( 11 ) in the installed state of the stack ( 3 ) abut the housing. Battery according to claim 12, characterized in that the elastic elements ( 11 ) abut against the housing under prestress. Battery according to claim 11, 12 or 13, characterized in that the groove has an arcuate contour in cross-section, wherein the elastic elements have a corresponding circular cross-section. Battery according to one of claims 11 to 14, characterized in that the elastic elements ( 11 ) are formed as hollow chamber profiles. Battery according to one of claims 1 to 15, characterized in that the intermediate element ( 9 ) is formed at least partially from metal and in the metallic regions with the corresponding electrical poles ( 7 . 8th ) of the two adjacent battery cells ( 2 ) connected is. Battery according to one of claims 1 to 16, characterized in that the intermediate element ( 9 ) with a separation across the stacking direction in two parts ( 9.1 . 9.2 ) is constructed of metallic material, each part ( 9.1 . 9.2 ) of the intermediate element ( 9 ) each with a pole ( 7 . 8th ) to the part ( 9.1 . 9.2 ) adjacent battery single cell ( 2 ) connected is.

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