WO2011012203A1 - Individual battery cells comprising a housing - Google Patents

Abstract

The invention relates to an individual battery cell (1) comprising a housing. In addition, it comprises a configuration of active material (electrode stack 5) in the housing. In addition, the housing also comprises an electrolyte in the region of the active material. According to the invention, at least one packing (8) of electrically insulating material is arranged in the housing.

Description

 Single battery cell with a housing

The invention relates to a single battery cell with a housing according to the closer defined in the preamble of claim 1.

The construction of batteries, especially of high-performance batteries, as they

used for example in electric vehicles or in hybrid vehicles, typically consists of a plurality of battery cells. Because of the high

Power density are preferred battery single cells used, which have a lithium-ion cell chemistry. Alternatively, too

Nickel metal hydride cells are used, but which have a significantly lower power density. The construction of such batteries or

High-performance batteries are now typically that of a variety of

Battery individual cells is interconnected. In general, this is a series connection of battery individual cells or optionally one

Parallel connection of individual groups in turn connected in series

Battery cells.

The battery cells may be in the most common embodiment

cup-shaped housing. Such round cells are typically provided with a wound-up electrode coil as the active material. Alternatively, a construction with prismatic cells is possible, which better exploit the typically available installation space, since cavities do not remain between the battery individual cells, as in the case of round cells. With such prismatic cells can thus be realized even higher power volume. A typical structure for such prismatic cells is described, for example, in the non-prepublished German application DE 10 2007 063 184.9. The structure of this so-called Frame flat cell provides that a frame made of an insulating material together with two cladding forms the housing of the battery single cell. Inside the frame, the active material array is then typically arranged as a stack of electrode foils. These electrode films are alternately stacked in accordance with their polarity and each electrically insulated from each other by a separator. The electrode stack is then connected to the corresponding cladding sheets, so that one cladding sheet forms one pole of the single battery cell, while the other cladding sheet forms the other pole of the single battery cell. This so-called bipolar structure has the advantage that by a simple juxtaposition or

Stacking the battery single cell already an electrical contact of the battery individual cells can be realized in the manner of a series connection. On one side of the stack of battery cells, one battery pole is then arranged, on the other side of the stack of battery cells, the other battery pole.

Regardless of the structure of a single cell battery must now in addition to the active material, which consists for example in a lithium-ion cell chemistry of aluminum-containing electrode films for one pole and copper-containing films for the other pole, a corresponding electrolyte, for example, a lithium-ion-containing solution or a Lithium-ion-containing gel, are introduced into the housing of the battery single cell. If there are corresponding cavities in the housing, as they typically occur in such housings, the electrolyte will not only collect in the region of the electrode stack or electrode winding, but also flow into the region of these cavities. In order to ensure that there is always a sufficient amount of electrolyte in the area of the electrodes, it must

a corresponding amount of electrolyte to be filled in order to prevent leakage of the electrolyte into the cavities and thus to leave parts of the active material without electrolyte. The case of the single battery cell must always be filled completely with electrolyte, which requires a correspondingly large amount of electrolyte.

It is now the object of the present invention to avoid the above-mentioned disadvantages and to achieve that a single battery cell with the lowest possible

Expenditure on costs can be produced. This object is solved by the features in the characterizing part of claim 1. Advantageous embodiments and variants of the solution according to the invention will become apparent from the dependent claims.

The use of at least one filling body to fill corresponding cavities in the battery housing, has the advantage that less total electrolyte is needed to completely fill the remaining volume of the battery case with this. Despite the smaller amount of electrolyte required can be ensured by the use of at least one packing that the entire free volume is filled with electrolyte and thus the electrolyte is present in all areas of the arrangement of the active materials accordingly, so that the available for the active material Space can be ideally exploited. The structure according to the invention with the filler can be used both in prismatic cells and in round cells.

In a particularly favorable embodiment of the invention, it is provided that the filler has a closed surface. This closed surface of the filling body makes it possible for the filling body to be sealed against the electrolyte and for no electrolyte to penetrate into the region of the filling body. Thus, on the one hand, absorption of electrolyte can be prevented so that no volumes without electrolyte arise in the region of the housing. On the other hand, swelling of the filler of electrically insulating material can be prevented thereby.

In a particularly favorable embodiment of the invention, the at least one filling body may be formed from an elastic material. This elastic material of the filling body is able to compensate for any length expansions of the materials of the battery single cell accordingly, without causing a correspondingly high pressure in the region of the battery single cell. These different ones

Material expansions may be, for example, different material expansions due to the heating of the housing and the arrangement of active material. The elastically formed at least one filler can also at

corresponding pressure fluctuations in the battery individual cells are compressed and relaxed again. Such pressure fluctuations generally occur during charging and discharging in the single battery cell. Due to the elastically formed filling body can act on the case of the battery Pressure fluctuations are reduced so that a longer life of the housing can be achieved without this shows leaks.

In a particularly advantageous embodiment of the battery single cell according to the invention, it is further provided that the at least one filler body of a

closed-cell foam is formed. Such a filling body

Closed-cell foam, which ideally has a closed surface, can realize the above-mentioned advantages. He is due to the

closed surface or at least after a short distance piece within the closed at least one filling body pores formed so that no / only little electrolyte penetrates into the packing. In addition, it has a certain elasticity, which allows the above advantages. Furthermore, such a packing of closed-cell foam is a very light component, so that hardly any additional mass is introduced into the structure of the single battery cell by the filling body.

As already mentioned above, the housing of the battery can be cup-shaped or prismatic. Due to the higher volume of power to be achieved, special attention is paid to the prismatic housings of the individual battery cells. Therefore, according to a particularly advantageous and advantageous development of the invention, the housing of the single battery cell is prismatic. In a corresponding embodiment thereof, it is further provided that the housing has a frame and two cladding sheets, wherein the arrangement of the active material is formed as a stack of electrode films and separators, and wherein each of the poles of the arrangement is respectively connected to one of the Hüllbleche. This results in a corresponding structure of the single battery cell as a so-called bipolar Rahmenflachzelle, which is equipped according to the invention with the at least one filler. This allows a high volume design with the least possible use of expensive electrolyte.

According to a particularly advantageous embodiment of the invention, it is provided that the frame is a step in the region of the connection of the arrangement with one of

Sheaths has. In a particularly favorable and advantageous development of this idea, it can further be provided that the at least one filling body is arranged in the region of the connection of the arrangement with the enveloping sheet, which does not lie in the region of this step. This structure allows the two typically resulting Cavities in the area in which the electrode stack connected to the respective cover plate, for example, welded, is to fill up accordingly. Due to the step-shaped design of the frame on the one hand and the insertion of a filling body on the other hand can be achieved that with simple and efficient means all larger cavities are filled with corresponding packing or the material of the frame itself. The structure as described here has the advantage that the frame can be sprayed onto one of the cladding sheets. There are no

Undercuts are possible in the area of the sprayed frame, the stage is realized so that it comes to rest on the cover plate, on which the frame is sprayed on the opposite side. In the area in which the connection of the electrode stack to the cladding to which the frame is sprayed on, the frame is formed correspondingly reset so that above the junction a corresponding cavity between the terminal region of the electrode stack and the opposite cladding, which still must be created arises. This cavity, whose equivalent on the

opposite side is filled by the step in the frame is now filled by the inventive at least one filler.

This filler may be formed as a separate insert, which is inserted accordingly, or it may, as in all other embodiments of the invention, be connected to a part of the housing. A corresponding part of the housing would be, for example, a housing cover, or in the specific embodiment described here, the one of the Hüllbleche. It may be particularly advantageous to spray the at least one filler on this one of the cladding with. This embodiment variant of the idea according to the invention not only makes it possible to save costs with respect to the use of the amount of electrolyte used, but also to achieve corresponding savings in the production, since the spraying of the frame onto one of the cladding sheets and, if appropriate, the

Packing on the other of the cladding each own manufacturing steps can be saved. Another advantage can be achieved by spraying the filler onto one of the cladding sheets. The filler can not only have the functionality of filling of corresponding cavities in the housing of the battery single cell, but it can also serve to secure the cover plate firmly connected with him during the manufacture of single battery cell safely and accurately against the frame before this firmly with the Frame is connected, for example by a hot pressing process. For this purpose, namely, a structure can be selected, in which molded-on filling body comes to rest on at least two surfaces of the frame already connected to the other covering sheet, so that the second covering sheet can be easily positioned without additional device.

Further advantageous embodiments of the invention will become apparent from the remaining dependent claims and from the embodiments, which are explained below with reference to the figures.

Showing:

 Fig. 1 is an exploded view of a single battery cell;

2 shows a cross section through such a battery single cell.

Fig. 3 is an enlarged detail of a portion of the cross section of FIG. 2; and FIG. 4 is a three-dimensional representation of an alternative construction of the

 Battery single cell.

In the embodiments, which are explained with reference to the following figures, a single battery cell 1 in each case by the example of a prismatic

Single battery cell 1, in particular in an embodiment as Rahmenflachzelle described. This construction of the single battery cell 1 is to be understood merely as an example, since other structures with prismatic housings or cup-shaped housings would be conceivable accordingly. On the basis of the embodiments described for the following examples of single battery cells 1, the person skilled in the art can easily apply the features essential to the invention to other types of construction

Adjust battery cells 1 analog.

The single battery cell 1 can be seen in the illustration of Figure 1 in an exploded view. In this case, a frame 2 can be seen, which can be laterally closed by a first Hüllblech 3 and a second Hüllblech 4. The frame 2 forms so together with the Hüllblechen 3, 4 a housing of the single battery cell 1, which is not provided here with its own reference numerals. Inside the frame 2, a stack 5 comes to lie on electrodes, which is known per se from the prior art and will be described in more detail with reference to one of the following figures. The electrode stack 5 has corresponding at two of its ends

Terminal areas 6, in which the anode foils on one side and the Cathode foils are led out of the electrode stack 5 on the other side. These connection areas 6 practically represent the poles of the arrangement of the active ones

These materials are correspondingly connected to the cladding sheet 3 or the cladding sheet 4, so that the cladding sheets 3 and 4 form the respective poles of the single battery cell 1.

On the cladding sheet 3, a beveled area 7 is also visible, which in the

assembled state below the frame 2 comes to rest. Also, the second cover plate 4 has a corresponding area, which, however, is difficult to see here. The two bevelled areas 7 are designed so that they do not touch each other below the frame 2, since they each have different polarities of the battery single cell 1, so that a contact would lead to a short circuit. The purpose of this also known from the prior art folds 7 is it, a possible large area for heat transfer from the Hüllblechen 3, 4 to a not shown here

To allow cooling device. This cooling device can, for example, after stacking the battery cells 1 as a cooled plate below the stack of

Battery individual cells 1 are arranged. The resulting waste heat from the

Single battery cells 1 can then be derived via the Hüllbleche 3, 4. The folded regions 7 of the respective cladding sheets 3, 4 are in heat-conducting contact with the cooling device, so that active cooling of the battery individual cells 1 in a manner known per se can take place via this contact. It can the

Cooling device may be formed, for example, as a cooling plate, which is connected via a thermally conductive and electrically insulating film with the battery cells 1, wherein the cooling plate itself is flowed through by a liquid coolant or an air conditioning coolant to cool the stack of the battery cells 1 accordingly active.

After the components of the battery single cell 1 shown here are connected to each other, this can be done for example by a hot pressing process. In this case, in which a thermoplastic material from which the frame 2 is formed, or which has the frame 2 in certain sub-areas, melted accordingly, so that a secure and tight connection between the frame 2 and the Hüllblechen 3, 4 takes place. In this structure, an electrolyte is then filled, for example, a liquid electrolyte. This must be present in the region of the electrode stack 5 between the corresponding electrode films in order to prevent the To operate single battery cell 1 in the desired manner electrochemically. In addition, it can be seen that in the region in which the one connection region 6 is connected to the first cladding sheet 3, a corresponding cavity will occur in the interior of the frame. Such cavities occur not only in the design described here accordingly, but can in all possible types of

Battery individual cells 1 occur accordingly. In order to ensure that the electrolyte is present everywhere in the region of the electrode stack 5, the electrolyte would have to be filled with the exception of the region of the electrode stack 5 into the region of this hollow space within the housing of the single cell cell 1. In this area, however, the electrolyte is not chemically active, since no corresponding active materials of the arrangement of the electrode stack 5 are present here.

In the illustration of Figure 1, therefore, a filler 8 can be seen. About this

Packing 8, the resulting in the final assembly of the single battery cell 1

Cavity are largely filled, so that the amount of required electrolyte can be reduced accordingly. This will allow for that volume

Costs incurred in the case of the material costs of the single battery cell 1

be saved accordingly.

As can be seen from the illustration in FIG. 1, the filling body 8 can also have corresponding means 9 for positioning in the housing of the single battery cell 1. These means 9 are hereby exemplified as grooves, which correspond with corresponding projections 10 in the region of the frame 2. This allows a simple, safe and accurate insertion of the filling body 8, which is to be designed here as a separate filler, can be achieved without this when assembling the battery single cell 1 changes its position and causes any damage, for example, to the electrode stack 5.

In the sectional view of Figure 2, this structure can be seen again, the electrode stack 5 is here shown comparatively indistinct. From the

corresponding enlargement of one side of the longitudinal section of Figure 2 in Figure 3, the structure is, however, to recognize more clearly. In the illustration of Figure 2, the frame 2 is shown together with the Hüllblechen 3, 4 and the electrode stack 5. It is clear here that the frame 2 in the area in which the connection area 6 of

Electrode stack 5 is connected to the second Hüllblech 4, a stage 11 has. This stage 11 fills the space below the terminal region 6 of the electrode stack 5 accordingly. On the opposite side of this structure with the stage is not visible. Instead, the already described packing 8 is arranged in the comparable area. This structure now has the advantage that the frame 2 can be connected to the cladding sheet 3 before the electrode stack 5 is inserted into the battery single cell 1. This bonding can be done for example by gluing or hot pressing. However, it is also conceivable to spray the frame 2 directly onto the first cladding sheet 3. The electrode stack 5 can now be connected with its connection regions 6 to the respective cladding sheet 3, 4, for example by welding, eg ultrasonic welding

Spot welding or the like. The construction is now such that the two enveloping plates 3, 4 connected to one another via the electrode stack 5 are still flexible enough to be held at a certain distance from each other via the flexibility of the foils of the electrode stack 5. Thus, the filler body 8 in the remaining cavity above the connection of the terminal portion 6 of the

Electrode stack 5 can be inserted with the first Hüllblech 3. Only then is the second cover plate 4 lowered onto the frame 2 and can be connected thereto, for example by a hot pressing method, gluing or the like. In addition to the saving of electrolyte, this construction also makes it possible to realize a very simple and inexpensive production since, for example, an additional manufacturing step can be saved by injecting the frame 2 on the first covering sheet 3.

In the illustration of Figure 3, the filler 8 can be seen in detail again in an enlarged section. In this illustration, the electrode stack 5 is also shown in such detail that the anode foils 12, the cathode foils 13 and the separators 14 arranged therebetween can be seen. The electrode stack 5 is formed such that the anode foils 12 and the cathode foils 13 are alternately stacked on each other, which are separated from each other by the electrically insulating separator 14. The anode foils 12 and the cathode foils 13 are formed in the preferred cell chemistry based on lithium ions while aluminum or copper or an aluminum or copper-containing material. The electrolyte used is typically a liquid electrolyte based on lithium ions. On one side of the electrode stack 5, shown here on the side of the anode, the anode foils 12 are led out of the electrode stack 5 and form corresponding to the connection area 6, which can then be connected to the first cover plate 3. In the illustration of FIG. 3, above this connection of the connection region 6 with the first enveloping sheet 3, the filling body 8 is located around the

To minimize void volume of the single battery cell 1. The filler 8 may be formed in a particularly favorable manner elastic or deformable. It can then, as indicated by the two arrows in Figure 3, exert a corresponding force on the connection portion 6, so as to ensure that it rests securely and firmly against the Hüllblech 3 and the connection is secured by the elastic properties of the filler 8 accordingly , In addition, resulting from the elasticity of the filling body, which may be formed, for example, as closed-cell foam, the advantages already mentioned above.

In addition to the separate packing 8, which in the area of the housing

Battery single cell can be inserted before the final assembly of the same, also a structure can be realized, in which the filler 8 is formed integrally with a part of the housing of the battery single cell 1. For this purpose, it would be conceivable, in the cladding sheet 4 in the area in which the filling body 8 is shown here, a

imprint corresponding trough, so that a part of the cladding itself the

forms corresponding filler. However, in this case an electrically insulating coating or the like is to be provided, since a direct contact of the enveloping sheet 4 with the connection region 6, which is connected to the enveloping sheet 3,

must be avoided, of course, as this is a short circuit of

Battery single cell 1 would result. Accordingly, the second enveloping sheet 4 can also be provided with an electrically insulating filling body 8, which is glued to the second enveloping sheet 4 or molded onto it. Such a structure is in the

Representation of Figure 4 can be seen. Here, the frame 2 is fixedly connected to the first Hüllblech 3, for example, molded onto this. With the Hüllblech 4 is the

Packing 8 firmly connected, for example, also molded on this. During assembly, then these two parts, so the unit of frame 2 and the first cover plate 3 and the unit of filler 8 and second cover plate 4, are simply placed on each other. Of course, the arrangement of active material, in particular the electrode stack 5, which can not be seen in the representation of FIG. 4, must first be introduced into the interior of the housing of the single battery cell 1. In addition to the advantage which results from the reduction of the production steps, a further advantage can be realized in the structure according to FIG. By firmly connected to the second Hüllblech 4 filler 8 and the fold 7, which comes to rest on the frame 2, two corresponding elements are now present, to which the structure of second Hüllblech 4 and 8 filling body rests against the frame 2 accordingly. This makes it possible to safely and reliably position the second cover plate 4 relative to the frame 2, so that in a later connection of the frame 2 with the cover plate 4, for example by a

Hot pressing method, on elaborate positioning aids for the cover plate. 4

can be waived accordingly.

In addition to the structure shown here and in particular in Figure 2 to be recognized with the stage 1 1 in the frame 2, it would of course also conceivable to introduce instead of the step 11 another filler 8 in this area, so that the frame 2 formed continuously with a rectangular cross-section can be.

Claims

claims A single cell battery comprising a housing having an arrangement of active material in the housing, the housing having an electrolyte at least in the area of the active material,  characterized in that  in the housing at least one filler body (8) made of electrically insulating material is arranged. 2. single battery cell according to claim 1,  characterized in that  the at least one filling body (8) has a closed surface. 3. single battery cell according to claim 1 or 2,  characterized in that  the at least one filler (8) is formed of elastic material. 4. single battery cell according to claim 1, 2 or 3,  characterized in that  the at least one filling body (8) is formed from a closed-cell foam. 5. single battery cell according to one of claims 1 to 4,  characterized in that the at least one filling body (8) is designed as a separate insert part. 6. single battery cell according to one of claims 1 to 5,  characterized in that  the at least one filler (8) is connected to a part of the housing. 7. single battery cell according to one of claims 1 to 6,  characterized in that  the at least one filling body (8) has means (9) for positioning in the housing. 8. single battery cell according to one of claims 1 to 7,  characterized in that  the housing is cup-shaped. 9. single battery cell according to claim 8,  characterized in that  the arrangement of active material as a winding of electrode films and  Separators is formed. 10. Single battery cell according to one of claims 1 to 7,  characterized in that  the housing is formed prismatic. 11. Single battery cell according to claim 10,  characterized in that  the housing comprises a frame (2) and two cladding sheets (3, 4), wherein the array of active material is formed as a stack (5) of electrode foils (12, 13) and separators (14), and wherein each of the poles of the array each with one of the Hüllbleche (3, 4) is connected. 12. single battery cell according to claim 11,  characterized in that  the frame (2) is sprayed onto one of the cladding sheets (3, 4). 13. single battery cell according to claim 11 or 12, characterized in that the at least one filler (8) is arranged in the region of the connection of the arrangement of active material (electrode stack 5) with one of the cladding sheets (3, 4). 14. single battery cell according to claim 10, 11 or 12,  characterized in that  the frame (2) has a step (11) in the region of the connection of the arrangement of active material (electrode stack 5) with one of the cladding sheets (3, 4). 15. single battery cell according to claim 14,  characterized in that  the at least one filling body (8) is arranged in the region of the connection of the arrangement with the one of the enveloping sheets (3, 4) which does not lie in the region of the step (11). 16. Single battery cell according to one of claims 1 to 15,  characterized in that  the electrode foil is formed from aluminum or an aluminum-containing material for one pole and copper or a copper-containing material for the other pole, wherein the electrolyte is formed as a liquid containing lithium ions.