WO2020002552A1 - Sealing segment for temperature control of a fluid-cooled battery - Google Patents

Abstract

The invention relates to a sealing segment (1) with two main surfaces (11, 12) and a passage opening (3), wherein an orthogonal projection of the sealing segment, which bears against a projection plane by way of a main surface, defines a segment projection outline, which surrounds a segment projection surface APS, and at least one opening projection outline, which surrounds an opening projection (total) area APF, the ratio APF to APS lies in the range of from 0.001 to 0.20, all opening projection outline points are at a distance from the segment projection outline and lie in a circumferential segment projection region, the segment projection region is delimited to the outside by the segment projection outline and has a circumferentially constant width which is selected such that the segment projection region takes up 75% of the segment projection area APS, wherein the sealing segment comprises a graphite foil layer (5).

Description

 SEALING SEGMENT FOR TEMPERATURE CONTROL

 FLUID-COOLED BATTERY

description

The invention relates to a sealing segment for a fluid-cooled battery and a sealing segment battery cell unit.

Battery modules are known which have a complex cooling pipeline system which forms a cooling circuit which is separate from the battery cell and the heat dissipation system (US2010279152A). These have the disadvantage that a large number of seals are required, which can leak over time and, on the other hand, there is thermal resistance between the heat dissipation system and the coolant. Complex, wound, fine branched piping systems are complex to manufacture.

DE 10 201 1 100 172 A1 describes a battery pack comprising a stack of battery cells and cooling fins. For liquid cooling / heating, each rib has coolant channels between two welded sheets, as well as coolant inlets and coolant outlets that extend from the ribs in ear-shaped features. A coolant should flow in through the inlet. From the first ear-shaped feature in which the inlet is located, the coolant flows in long coolant channels within the cooling fin to the other ear-shaped feature in which the outlet is located and exits the cooling fin there. A high amount of sealing occurs between the ear-shaped features of successive ribs. In order to fill the gap between the ribs and to provide a proper coolant seal, it is suggested to mold the ear-like extensions with plastic that is sealable. Alternatively, rubber seals should be used. DE 10 201 1 109 306 A1 proposes U-shaped elements with cooling fluid channels. A carrier plate with a battery cell attached to it should be arranged on a U-shaped element such that a fluid flowing through the cooling fluid channel flows along the surface of the carrier plate and extracts heat from the carrier plate. Cooling fluid channels are each formed between the U-shaped elements and the carrier plate. Sealing is therefore essentially required over the entire length of the coolant channels. It is proposed that adhesive be applied over a large area or that the U-shaped elements be poured directly onto the carrier plate in order to achieve a seal. Sealing is therefore only possible with great effort and there is a considerable risk of leakage due to the length of the seals.

The present invention has for its object to provide a sealing segment for a vehicle drive, e.g. of a car (BEV or HEV), aircraft or ship to provide a battery that can be adapted as flexibly as possible to the spatial conditions that exist in the motor vehicle and that achieves efficient cooling and a high energy density with a simple battery construction without create increased risk of coolant leaks.

This object is achieved by a sealing segment having a first main surface (which can, for example, be conceived as the front) and a second flap surface (which can, for example, be conceived as the rear), which merge into one another at the edge of the sealing segment, and at least one passage opening, which Sealing segment penetrates from the first main surface to the second main surface, wherein an orthogonal projection of the sealing segment lying with a main surface on a projection plane has a segment projection outline that surrounds a segment projection surface AP _S and at least one opening projection outline that covers an opening projection (total) surface A _PF surrounds, defines, the ratio A _PF to A _PS in the range of 0.001 to 0.20, all opening projection outline points are spaced from the segment projection outline and lie in a circumferential segment projection area, the segment projection area is limited to the outside by the segment projection outline and has a circumferentially constant width which is chosen such that the segment projection area is 75% of the segment projection area A _PS assumes, the sealing segment comprising a graphite foil layer.

The orthogonal projection is understood to mean the mapping of the sealing segment onto a projection plane, so that the connecting line between a point of the sealing segment and the image of this point forms a right angle with the projection plane. This applies to every point of the sealing segment and the connecting line leading to the representation of this point; it is therefore a special form of parallel projection. In the case of orthogonal projection, the sealing segment which is in contact with a main surface on a projection plane is oriented in such a way that the segment projection surface A _{PS is} as large as possible. Depending on the shape of the main surface, it can, for example, lie completely against the projection plane (in the case of a flat main surface), with only a part of the main surface or with only one or more points of the main surface (if the main surface is not completely flat). The two main surfaces merge into one another at the edge of the sealing segment and at the edge of the passage opening. The transitions can include end faces at the edge of the sealing segment and at the opening edge, as can be seen, for example, from FIGS. 1B and 1C.

The end faces typically run approximately orthogonally to the first and second main surfaces and result, for example, by processing a flat material from which the sealing segment is made by cutting, water jet cutting, laser cutting or punching. However, the edge areas can also have other shapes and, for example, include end faces with rounded transitions to the main areas. The orthogonal projection of the sealing segment lying with one main surface on the projection plane defines a segment projection outline. The segment projection outline surrounds the segment projection area A _PS . The orthogonal projection also defines at least one opening projection outline. The at least one opening projection outline surrounds the opening projection (total) area A _PF . If there is only one passage opening and thus only one opening projection outline, one speaks of an opening projection area A _PF . If there are several through openings and thus several opening projection outlines, one speaks of an overall opening projection area A _PF

The segment projection area A _P s includes the opening projection area (total) area A _PF , since the at least one opening projection outline runs completely within the segment projection outline. The sealing segment comprises a graphite foil layer. The graphite foil layer extends in the sealing segment. Due to the high thermal conductivity of the graphite foil in the plane, the flat heat distribution in the sealing segment is accelerated.

The compressibility of the graphite foil also offers advantages. It increases the tightness of the battery in the area between the frame and the sealing segment. The graphite foil at least partially compensates for a volume expansion of a battery cell adjacent to the sealing segment, for example a pouch cell. In this respect, it is advantageous if the layer of graphite foil extends to the edge of the sealing segment. Furthermore, it is preferred if the graphite foil layer extends in the sealing segment to a point which, in the orthogonal projection, is closer to the segment projection area center than the opening projection outline point closest to the segment projection area center of gravity. At this point, changes in volume of the battery cell can be at least partially compensated for by the graphite foil. In very particularly preferred sealing segments according to the invention, the projection area of the graphite foil in the orthogonal projection takes up more than 90%, in particular more than 95%, for example more than 98% of the segment projection area A _PS . The graphite foil layer can be a synthetic graphite foil layer formed from polymers. However, the graphite foil layer preferably comprises a partially compacted graphite expandate.

The production of graphite foil layers which comprise a partially compacted graphite expandate is generally known. As is known, they can be produced by treating graphite with certain acids, a graphite salt being formed with acid anions embedded between graphene layers. The graphite salt is then expanded by using it at high temperatures e.g. Exposed to 800 ° C. For example, in order to produce expanded graphite (graphite expandate) with a worm-like structure, graphite, such as natural graphite, is usually mixed with an intercalate, such as, for example, nitric acid or sulfuric acid, and at an elevated temperature of e.g. 600 ° C to 1200 ° C heat treated (see

DE10003927A1). The expanded graphite obtained during the expansion is then pressed into the graphite foil. A method for producing graphite foils is described, for example, in EP 1 120 378 B1. DE 10 2012 202 748 A1 also describes a method for producing a graphite foil. The pressing can be controlled so that graphite foils are obtained which are very strong. If the expanded graphite is compressed only slightly (for example to a density in the range from 0.2 to 0.7 g / cm ³ ), a relatively flexible layer of graphite foil is obtained, for example, with a thickness of 0.5 mm. If one presses to higher densities of, for example, 1.5 to 1.9 g / cm ³ , the graphite foil layer obtained is essentially inflexible and plate-like with the same thickness. The sealing segment preferably has an electrically insulating coating on at least one main surface. The coating can be formed, for example, from a plastic, preferably from polyethylene terephthalate (PET) or PTFE, for example expanded PTFE (ePTFE). This has the advantage that even if a battery cell is damaged, undesired electrical charging of the sealing segment is avoided.

The electrically insulating coating can essentially completely cover both main surfaces, e.g. cover more than 90%. The edge of the passage opening can be completely covered by the electrically insulating coating. This has the advantage that a fluid used for cooling, which flows through the passage opening, cannot penetrate into the sealing segment in the region of the opening. The sealing segment then remains intact longer and has to be replaced even less frequently.

In a particularly preferred embodiment, the sealing segment consists of the flat material containing expanded graphite, which is specified in WO 201 1/101391 A1. This enables good thermal conductivity in the surface direction with simultaneous adaptability to changes in volume of the battery cells in both directions - volume expansion and volume reduction. In addition, the graphite-containing flat material of the sealing segment can be adapted particularly well to the most varied forms of battery cells.

In one embodiment of the invention, the sealing segment has a density of 0.6-1.9 g / cm ³ , preferably 0.7-1.4 g / cm ³ and particularly preferably 0.9-1.1 g / cm ³ such as advantageous 1.0 g / cm ³ . In a further embodiment of the invention, the sealing segment has a thermal conductivity in the surface direction of 120-500 W / (m K), preferably 130-480 W / (m K) and particularly preferably 250-450 W / (m K) , Thermal conductivity is measured using the Angström method (“Angström's Method of Measuring Thermal Conductivity ”; Amy L. Lytle; Physics Department, The College of Wooster, Theses).

In one embodiment of the invention, the sealing segment has a springback of 2 to 6%, preferably 2.5 to 5.5% and particularly preferably 3 to 5%, based on its initial thickness, in the thickness direction. The springback is determined in accordance with sections 9.1, 9.2 and 9.2.1 of the

DIN 28090-2: 1995-09. It has now been found that this effectively counteracts an undesired leakage of cooling fluid in the areas in which the sealing segment lies against the frame. Materials with high coefficients of thermal expansion can then also be used for the frames, such as Polymer-based plastic frame. The resilience of the sealing segments compensates for the twisting of the frames associated with local temperature fluctuations, thus ensuring a high level of tightness e.g. even when the vehicle starts at particularly low outside temperatures.

 This enables targeted local compaction in the edges of the sealing segments which are in contact with the frame if the sealing segments are clamped between the frames. An undesirable leakage of cooling fluid is thereby made even more difficult. The frames can then be manufactured with higher manufacturing tolerances, with unevenness being particularly well compensated for by compressible sealing segments. When plastic frames are injection molded, relatively high manufacturing tolerances are specifically accepted in favor of higher manufacturing efficiency. Sealing segments which can be used according to the invention thus enable particularly efficient battery production and are preferably used in conjunction with plastic injection molding frames.

The sealing segment can preferably consist of compressed graphite expandate. In an alternative embodiment, the sealing segment can consist of a mixture of largely uniformly mixed graphite expanded material and plastic particles formed before the compression. In a further alternative embodiment the sealing segment can be impregnated with plastic applied after the compression on the surface or up to the core area of the sealing segment. By means of these embodiments, particularly dimensionally stable and easily manageable sealing segments can advantageously be formed. Thermoplastics, thermosets or elastomers, in particular fluoropolymer, PE, PVC, PP, PVDF, PEEK, benzoaxines and / or epoxy resins, can advantageously be used as plastics.

In order to enable a particularly good heat transfer from a battery cell to the sealing segment, the sealing segment can be adapted to an outer contour of the battery cell. For example, the sealing segment can have a recess for the form-fitting reception of a part of an outer surface of a battery, the recess being specifically designed for the partial reception of certain cylindrical or prismatic batteries, in order to allow a battery to hug as large a surface as possible to a main surface of the sealing segment to allow.

In a preferred sealing segment, one or both of the fluff surfaces are essentially flat. This has the advantage that essentially flat surfaces of pouch cells can rest on the heat exchange surface, thereby ensuring efficient heat transfer.

To ensure that the battery cells, e.g. In order not to impede the expansion of the pouch cells, the sealing segments and the battery cells can advantageously be clamped to one another in the inoperative and discharged state of the energy store in such a way that the sealing segments are compressed only slightly in the thickness direction, preferably by at most 1% based on their initial thickness ,

The number of through openings is not limited. It can be 1, 2, 3, 4, 5 or 6, preferably 1, 2, 3, 4 or 5, further preferably 1, 2, 3 or 4, particularly preferably 1, 2 or 3, for example 1 or 2. In a very particularly preferred sealing segment according to the invention, the number of passage openings is 1.

All opening projection outline points are spaced from the segment projection outline.

If the sealing segment has more than one passage opening, they are located

Through openings are preferably either grouped close together or far apart

A grouping of passage openings close to one another has the advantage that turbulence of the cooling fluid during passage also at lower

Flow speeds are favored. In any case, this applies in comparison to a single passage opening whose opening projection area corresponds to the total opening projection areas of the grouped passage areas.

If there are several passage openings (or groups of passage openings), on the other hand, they should be as far apart as possible. Because this makes it possible in the first place to arrange a passage opening of the sealing segment following in the battery cell stack in the middle between two passage openings in such a way that the cooling fluid flows along the surfaces of the sealing segments over longer distances. This is because the present invention enables particularly effective cooling, inter alia, in that a cooling fluid is guided specifically along the surface of the sealing segment.

The details given in the previous three sections can be specified

preferred distances from through openings as follows:

No opening projection outline point of an opening projection outline is closer to an opening projection outline point of another opening projection outline than 5%, in particular 8%, particularly preferably 10%, for example 15% of the length of the segment projection outline. This only does not apply with regard to the opening projection outlines of grouped openings among one another. Consider as grouped

Passage openings if all opening projection outline points of one

Passage opening a distance of less than 4% of the length of the

 Segment projection outline to an opening projection outline point of a

Take the opening projection outline of at least one other passage opening. The opening projection outline points mean the points which form the opening projection outline or, if there are several passage openings, form the opening projection outline.

All opening projection outline points lie within a circumferential segment projection area. The circumferential segment projection area is limited to the outside by the segment projection outline. The circumferential segment projection area has a circumferentially constant width. The width is selected so that the circumferential segment projection area occupies 75%, preferably 65%, further preferably 55%, particularly preferably 45%, very particularly preferably 35%, for example 30% of the segment projection area A _PS . Circumferential segment projection areas of constant width can be specified for each segment projection outline, as exemplified in FIGS. 4A to 4D.

According to the invention, the passage opening (s) are therefore located in an outer area of the sealing segment, which is delimited with the aid of the orthogonal projection and the circumferential segment projection area. This means that an inner area of the sealing segment surrounded by the outer area is available for a flat thermal contact between the battery cell (s) and the main surface (s). A battery constructed with sealing segments according to the invention can be flexibly adapted to the spatial conditions that exist in a motor vehicle. The sealing segment enables a stacked structure of a battery, as shown for example in FIG. 7. The shape of the sealing segments and the length of individual stacks are essentially freely selectable, so that the flea spaces that are available for a traction battery in a certain type of motor vehicle can be used as completely as possible.

For example, an elevation between the seats of a car, e.g. a cardan tunnel, a given shape and cannot be extended into the passenger compartment at will. In order to use the space available there as completely as possible, a battery could be built based on trapezoidal sealing segments. Sealing segments with an essentially rectangular, triangular, oval or round segment projection surface are also conceivable.

If several batteries are to be arranged directly next to one another or one above the other at other points, fluff spaces between the batteries are generally not desirable since these cavities are difficult to use in other ways. In this case, a sealing segment with an essentially rectangular segment projection surface is recommended, since stacks constructed therefrom can be arranged next to one another with almost no unwanted cavities.

With the sealing segment according to the invention, efficient cooling and a high energy density are achieved with a simple construction. With various elements of a battery that can be assembled with sealing segments according to the invention, the sealing segments bring about synergistic advantages, as described in the following paragraphs. The sealing segments create a seal by being able to be connected directly to the frame; they can be clamped between the frames (sealing function). In addition, the sealing segments position the battery cells in the desired position in the cell stack (positioning function). They allow a defined, punctual passage of cooling fluid through the passage openings and limit the sections of the channels running between passage openings in the stacking direction (fluid guide function). At the same time, excess heat from battery cells is transferred directly to the sealing segments. The heat is also distributed in the sealing segment into areas further out, where one or more main surfaces of the sealing segment are in contact with a cooling fluid to which the heat is transferred (thermal conductivity function).

If the sealing segments are firmly clamped between the frames, the battery behaves like a single solid body that can be anchored to the frame in the motor vehicle (positioning function). The frames form a wall of the cooling channel, so that a cooling fluid can flow along a surface of the frames in the cooling channel (fluid guide function).

In the present invention, the battery cells not only serve to provide electrical energy, but also limit the cooling channel. They help ensure that the fluid is guided along the battery cell (fluid control function). At the same time, this causes efficient cooling, since the cooling fluid flows along the cell surface. The sealing segments make components that would be required according to the state of the art unnecessary. A cooling channel, which extends over the entire length of the stack-like structure of the battery and which surrounds the individual battery cells, is, as is incidentally, defined by frames, sealing segments and battery cells when using the sealing segments according to the invention (see in particular FIGS. 3, 4 and 5) without the need for separate components. This ensures a particularly simple construction.

As a result, particularly efficient cooling of the battery cells is achieved. Excess heat is transferred from battery cells via the sealing segments to the cooling fluid, as described above (first heat path). In addition, excess heat is transferred directly from the battery cells to the cooling fluid, since the cooling channel defined by the sealing segments and their passage openings runs along the battery cells (second heat path). Since heat escapes from the battery cells at the same time over several heat paths, adequate cooling is also possible with relatively low cooling fluid volume flows or with less cold cooling fluids. In this respect, the sealing segment is used according to the invention for temperature control.

Only a relatively small amount of cooling is required. The cooling fluid is also continuously available for heat absorption during the transition from one battery cell to the next. The sealing segments according to the invention can be arranged in such a way and the passage openings can be positioned such that a continuous flow around the battery cells is possible. As a result, dead volumes in which the cooling fluid is not available for absorbing heat from battery cells are kept to a minimum. As a result, the sealing segment according to the invention ultimately enables the heat absorption capacity of the cooling fluid to be used particularly economically, which enables the use of particularly small coolant volumes.

Relative to the entire battery including coolant, this results in particularly high energy densities.

The ratio A _PF to A _PS is in the range from 0.001 to 0.20, preferably from 0.003 to 0.175, further preferably from 0.004 to 0.15, particularly preferably from 0.004 to 0.125. With an even smaller ratio of these areas, the flow Resistance of a cooling fluid is too high even with short stacks with only a few sealing segments. A fluid delivery device, such as a pump, would then use too much energy to deliver sufficient amounts of cooling fluid through the stack. With an even larger ratio of these areas, the heat removal from the battery cells is impaired too much, since the passage opening (s) then uses up too much of the area available for heat exchange (heat conduction in the graphite foil layer).

The shape of the sealing segment is not limited. Basically, all shapes are possible. Special shapes may be required in order to form a traction battery for a specific motor vehicle flea space. In general, however, shapes with short sealing segment edges are preferred, since this further reduces the likelihood of cooling fluid leaks and swelling of the sealing segments due to absorption of cooling fluid over the end faces. For example, the length of the segment projection outline exceeds the circumference of a square, the area of which corresponds to the segment projection area A _PS , at most by 65%, preferably at most by 30%, particularly preferably at most by 10%.

Preferably, the segmental projection outline does not include a concave section. A concave section exists if a straight line can be placed in the segment projection outline in such a way that it intersects the segment projection outline in more than two points and the partial areas of the segment projection area enclosed between the straight line and the segment projection outline amount to at least 3% of A _PS ,

It is less preferred if a passage opening lies in a peripheral area of a sealing segment according to the invention. Orthogonal projections of less preferred sealing segments, in which the passage opening is located in peripheral tabs protruding from the regular base area, are illustrated in FIGS. 3A and 3B. Preferred sealing segments according to the invention can be derived from these Use a polygon to delimit sealing segments, which is used to define the preferred position of the passage opening. It is preferred according to the invention if the opening projection outline lies in the segment projection outline such that there is an equilateral and equiangular polygon, for example a square, the area of which is an eighth, generally a sixth, preferably a fifth, further preferably a quarter and particularly preferred is a third of A _PS , aligned within the segment projection outline so that the opening projection outline lies completely within the polygon. According to the invention, less preferred positions of the passage opening in the sealing segment can be specified not only with the aid of the polygon or square, but instead or in addition to the polygon also with the help of a family of straight lines which intersect the opening projection outline in one or more points. The opening projection outline is preferably in the segment projection outline in such a way that none of the straight lines which intersect the opening projection outline at one point or more points intersect the first segment projection outline at more than two points.

If the passage opening is not in a peripheral region of the sealing segment, the flow resistance is reduced since the cooling fluid does not have to be led into peripheral regions in order to flow through the sealing segment through the passage opening.

According to the invention, the distance from the opening projection outline to the segment projection outline never falls below 50%, preferably 75%, particularly preferably 100% of the sealing segment thickness. This has the advantage that the area of the sealing segment that extends between the passage opening and the segment edge is consistently wide enough and can be securely clamped between the frames without bending or performing any other evasive movements when braced. This reduces the risk of undesirable coolant leaks. The distance from The opening projection outline to the segment projection outline is measured in the orthogonal projection. The seal segment thickness is determined according to DIN EN ISO 5084 from October 1996. The seal segment thickness is measured in the orthogonal projection direction. A pressure stamp with a round test surface is used, the diameter of which corresponds to the shortest distance from the opening projection outline to the segment projection outline, whereby this is placed on each thickness measurement so that the line along which the respective distance from the opening projection outline to the segment projection outline is measured , divides the test area into two halves of equal size. The thickness of the sealing segment is determined at a pressure of 0.1 kPa, this pressure specification relating to the round test surface of the pressure stamp.

At least a first and a third section of the sealing segment edge preferably run parallel to one another. This has the advantage that the sealing segment can then be guided particularly easily between two parallel frames, which makes it particularly easy to replace individual components of a battery, such as sealing segments and battery cells attached to them.

It is further preferred if at least a region of the sealing segment edge which connects the first and the third section of the sealing segment edge comprises a second section of the sealing segment edge which is orthogonal to the first and third section of the sealing segment edge.

Another area of the sealing segment edge, which connects the first and the third section of the sealing segment edge, comprises a fourth section of the sealing segment edge, which runs parallel to the second section of the sealing segment edge.

The edge of the sealing segment preferably has at least four straight sections and four straight lines coinciding with these sections define a square. The segment surface preferably does not protrude beyond this square. For example, define a rectangle with the first, with the second, with the third and with the fourth section of the sealing segment edge, and the segment surface does not protrude beyond this rectangle. This ensures that the segment edge is short in relation to the segment area, which, given the cooling capacity, is relatively low risk of undesired leakage of cooling fluid and ensures low-risk operation of the motor vehicle.

The sealing segment can meet the following conditions: di = xd ₃ , and

d ₂ = yd.

Here di stands for the distance from the opening edge to the first section of the sealing segment edge, d ₂ for the distance from the opening edge to the second section of the

Sealing segment edge, d ₃ for the distance from the opening edge to the third section of the sealing segment edge, d ₄ for the distance from the opening edge to the fourth section of the sealing segment edge, x for a number in the range from 0.25 to 4 and y for a number in the range from 3 to 50. This ensures that the passage opening is close to the second section and far away from the fourth section.

The distance from the first to the third section is preferably greater than the distance from the second to the fourth section. The invention also relates to a sealing segment battery cell unit comprising a battery cell, the battery cell being in thermal contact with a main surface of a sealing segment according to the invention. The thermal contact can be formed in that the battery cell with one of the main surfaces of the sealing segment or with an electrically insulating arranged on this main surface Coating is in physical contact, with the battery cell not overlapping the passage opening. The battery cell does not overlap the passage opening if there is no opening projection outline point in the projection outline of the battery cell in the orthogonal projection.

The battery cell is preferably selected from prismatic cells, pouch cells and cylindrical cells. Particularly preferred sealing segment battery cell units are sealing segment pouch cell units. The particularly preferred battery cell is therefore a pouch cell.

The battery cell, for example a pouch cell, is not restricted with regard to cell chemistry. A reversible oxidation of lithium to Li ⁺ cations is preferably involved in the provision of electric current. Preferably, the pouch cell has a front and a back, which are essentially flat and run parallel to one another. The front and the back take up at least 50%, for example at least 60%, preferably at least 70% of the entire surface of a bag which closes off the pouch cell from the outside. A frame preferably lies against the main surface (or against the electrically insulating coating) with which the battery cell is in thermal contact in such a way that a channel is formed which is delimited by the battery cell, sealing segment and frame and into which a fluid flows through the passage opening can. The channel is preferably circumferential, ie the projection outline of the battery in the orthogonal projection maintains a defined distance from the projection outline of the frame. Each point of the projection outline of the battery preferably maintains a distance from the projection outline of the frame which is at most 20% of the length of the segment projection outline, for example at most 10% of the length of the segment projection outline. In addition, each point of the projection outline preferably stops a distance from the battery to the projection outline of the frame which is at least 0.1% of the length of the segment projection outline, for example at least 0.5% of the length of the segment projection outline. This ensures that a cooling fluid can flow through even particularly narrow areas of the cooling channel unhindered and at the same time the cooling fluid flow does not come to a standstill in particularly wide channel areas. This increases the heat dissipation and thereby ultimately the energy density of the battery and / or the service life of the battery cells.

A particularly preferred sealing segment-battery cell unit comprises a second sealing segment according to the invention, wherein a main surface of the second sealing segment lies against the frame in such a way that the fluid that can flow into the channel through the through opening of the one sealing segment passes through the through opening of the second sealing segment can escape from the channel. The first and the second sealing segment generally lie so firmly against the pouch cell that the pouch cell does not slip between the sealing segments.

In the orthogonal projection, the segment projection outline of the second sealing segment preferably coincides with the segment projection outline of the first sealing segment. This means that at least 95%, preferably at least 98% of the segment projection falls of the second seal segment in the segment projection A _PS and falls that at least 95%, preferably at least 98% of the segment projection A _PS in the segment projection of the second seal segment.

In the orthogonal projection, each opening projection surface of the first sealing segment generally holds to every opening projection surface of the second sealing segment mean a distance. This distance is preferably at least one fiftieth, particularly preferably at least one twentieth, for example at least one tenth of the length of the segment projection outline of the first sealing segment. The passage opening of the first sealing segment and the passage opening of the second sealing segment are preferably connected via two sections of the channel of the same length. The length of the sections of the channel is determined in the orthogonal projection, for which purpose an auxiliary straight line is drawn through the two centroids of the opening projection surfaces. The projection of one section of the channel then runs on one side of the auxiliary straight line and the projection of the other section of the channel runs on the other side of the auxiliary straight line. The length of a section of the channel is the shortest connection from the opening projection outline of one sealing segment to the opening projection outline of the other sealing segment, which does not intersect the projection outline of the battery cell. There are two sections of equal length if the longer section is at most 50%, preferably at most 15% longer than the shorter section. This favors that almost the same amount of heat is transferred to the cooling fluid in all parts of the outer regions of the sealing segments and thus a uniform heat dissipation from all parts of the cell. So-called hot spots that damage battery cells are then less pronounced. Ultimately, this extends the life of the battery cells and a traction battery built up with them.

For the secure heat-conducting connection of the sealing segment to the battery cells, the sealing segment can be designed in such a way that it gives in when the volume of the battery cell that can be attached to it expands and expands when the volume of the battery cells is reduced. In order not to impede the volume expansion that occurs only when the battery cells are in operation, the sealing segments and the battery cells can advantageously be clamped to one another when the energy store is inoperative in such a way that the sealing segment of the sealing segment or segments in Thickness direction is compressed only weakly, preferably by at most 1% based on its initial thickness.

The sealing segments according to the invention are suitable for temperature control in very different batteries. They are particularly suitable for temperature control in high-performance batteries, e.g. in traction batteries in BEV or HEV. BEV refers to a motor vehicle for the transport of people and / or goods, which is driven by an electric motor and which draws the electrical energy required for its movement from the traction battery. HEV refers to a motor vehicle for the transportation of people and / or goods, which is driven by an electric motor and another energy converter and which partly obtains the electrical energy required for its movement from the traction battery.

It is possible to clamp a battery cell between the sealing segments according to the invention and to align them at the same time with the aid of the current-conducting elements in such a way that no further suspension elements are required. This is advantageous because a battery can be easily, i.e. can be assembled with a few simple components. Alternatively, a suspension element can be arranged on the first and / or second main surface or on the electrically insulating coating which is attached to the main surface or the main surfaces, the suspension element emerging, for example, from the main surface. The suspension element can e.g. Foam, graphite and / or a solid metal such as e.g. Steel or aluminum. Sliding of a battery cell arranged on a main surface or an electrically insulating coating is additionally made more difficult by the suspension element.

The suspension element can also be a bracket on which the battery cell is suspended between the sealing segments according to the invention. The bracket can, for example, together with the current-conducting elements in an outside of one Extend frame lying area. The bracket can extend around a battery cell, for example a pouch cell, arranged between two sealing segments.

The invention also relates to a traction battery which comprises a stack of sealing segment battery cell units according to the invention.

The invention also relates to the use of an electrically non-conductive liquid for removing heat from a sealing segment according to the invention, from a sealing segment battery cell unit according to the invention or from a traction battery according to the invention.

Electrically non-conductive means that the liquid does not conduct electrical current. The conductivity is at most 10 ^-8 S-crrf ¹ or the specific electrical resistance is 10 ⁸ W-cm, measured at 25 ° C. It is measured according to DIN EN 60247: 2004.

The use of electrically non-conductive liquids as the cooling fluid has the advantage that there is no short circuit in the event of damage and thermal runaway of a battery cell.

The electrically non-conductive liquid preferably contains a fluorinated organic compound, for example a fully fluorinated organic compound or a partially fluorinated organic compound such as for example a fully fluorinated ketone, or a partially fluorinated ether. The boiling point of the compound determined at a pressure of 1 bar can be, for example, in the range from 45 to 150 ° C., preferably in the range from 55 ° C. to 100 ° C. In fully fluorinated ketone, a seven-fold fluorinated isopropyl group and a five-fold fluorinated ethyl group can be attached to the keto carbon. Further special features and advantages of the invention result from the following description of exemplary embodiments with reference to the drawings. Show it:

1A shows a sealing segment according to the invention;

Fig. 1 B, 1 C two different perspectives of a corner area of the in

 FIG. 1A shows the sealing segment (the corner region is highlighted with a rectangle at the top right in FIG. 1A);

 2, 3A, 3B, 3C orthogonal projections of sealing segments according to the invention;

 4A to 4D the definition of a peripheral segment edge area on

 Example of the orthogonal projection of Figure 3B;

5 shows a sealing segment battery cell unit according to the invention;

6 shows a section through a sealing segment battery cell unit according to the invention;

7 shows a part of a traction battery which is constructed from sealing segment battery cell units according to the invention.

FIG. 1A shows a sealing segment 1 for temperature control of a fluid-cooled battery. The sealing segment 1 has a first flap surface 11 and a second flap surface 12. The sealing segment 1 also has a passage opening 3 which penetrates the sealing segment from the first main surface 11 to the second main surface 12. The second main surface 12 cannot be seen in FIG. 1A, since it is located on a side facing away from the viewer and runs essentially parallel to the first main surface 11, as can be seen from the perspective shown in FIG. 1C. In the perspective shown in FIG. 1C, both main surfaces run towards the viewer. The two main surfaces 11, 12 merge into one another at the sealing segment edge 2 and at the opening edge 4. FIG. 1B shows an example of how the main surfaces 11, 12 can merge into one another at the edge of the sealing segment. Here, the edge 2 forms a surface that is essentially orthogonal to the main surfaces 11 and 12. However, any other transition of the main surfaces 11, 12 in the edge region is also conceivable, for example over a rounded edge. The opening edge 4 surrounds a passage area.

The sealing segment shown in FIG. 1A consists of a graphite film 5, which essentially consists of compacted graphite expandate, which is partially compressed to a density of 1.5 g / cm ³ . The sealing segment thus comprises a graphite foil layer.

The position of the passage opening 4 in the sealing segment is defined via an orthogonal projection. This is illustrated by the orthogonal projections 1 _P shown in FIGS. 2, 3A, 3B, 3C by way of example for four different sealing segments, not shown, in which the two main surfaces 11 and 12 are each flat and essentially parallel to one another and not to one another shown projection plane.

FIGS. 2, 3A, 3B and 3C show the respective segment projection outline 2 _{P which} surrounds the respective segment projection area A _PS , which is also shown. In addition, the opening projection outline 4 _P and the respective opening projection area A _P F are shown. It is obvious that the ratio A _PS to A _PF in the examples is not less than 0.004 and not more than 0.10 and that in all examples all points of the opening projection outline 4 _P (ie all opening projection outline points) are spaced from the segment projection outline 2 _P.

In addition, in the projections shown in FIGS. 2, 3A, 3B and 3C, all of the opening projection outline points lie in a circumferential segment projection area 0 _P , which has a circumferentially constant width b and is limited to the outside by the segment projection contour 2 _P. In FIG. 2, the segment projection area is 0 _P , the has a constant constant width b, highlighted by cross-hatching. The width b is chosen so that the segment projection area Op occupies 75% of the segment projection area A _PS . It is determined as follows whether all of the opening projection outline points are in this circumferential segment projection region Op (the following steps are illustrated in FIGS. 4A to 4D for the orthogonal projection shown in FIG. 3B):

 - First, a point X of the opening projection outline is determined which is further or the same distance from the segment projection outline than all other points of the opening projection outline (see X in FIG. 4A). If necessary, all points of several opening projection contours must be taken into account if a sealing segment has several through openings.

 Then the distance of this point X from the segment projection outline is measured (see double arrow in FIG. 4B).

 - A line is drawn within the segment projection outline that maintains this distance from the segment projection outline. Such a line can e.g. sketch with a compass and a multitude of circles, the centers of which are on the segment projection outline and the radius of which corresponds to the distance shown in FIG. 4B (see FIGS. 4C, 4D). The arrow pointing to the left indicates a tip of the line pointing to the left, which can be clearly seen in FIG. 4D.

 - The ratio of the area enclosed between this line and the segment projection outline to the segment projection area is then determined. If the ratio of the two areas is at most 0.75, there is a sealing segment according to the invention. It can easily be seen from FIG. 4D that the ratio in the case shown there is below 0.75.

In the orthogonal projections shown in FIGS. 2, 3A, 3B and 3C, the length of the segment projection outline 2 _P exceeds the circumference of a square, whose area corresponds to the segment projection area AP _S , only slightly. The segment projection area A _PS has the shape of a rectangle in FIG. 2, the ratio of the length to the width of this rectangle being 2: 3. For a rectangle with a length to width ratio of 2: 3, the edge is only about 2% longer than for a square with the same area. In FIG. 3B, the segment projection area A _{PS has} the shape of two adjoining rectangles of different sizes, each with a length to width ratio of 5: 6, the area of one rectangle being 15 times the area of the other rectangle. The segment projection outline 2 _P is here about 28% longer than for a square with the same area

In Figure 2, the opening projection outline 4 _P is located in the segment projection outline 2 _P so located that a square P ₂ whose area is one-sixth of A _PS, within the segment projection outline 2 can align _P so that the opening projection outline 4 _P completely within the square P ₂ lies. A square P _{3 can also be} aligned in the same way, the area of which is one fifth of A _PS and a square Pi, the area of which is one eighth of A _PS . The orthogonal projections shown in FIGS. 3A and 3B do not meet these conditions, as can be seen from the squares shown there. A suspension element can be arranged on the first main surface 11 and / or the second main surface 12. In the examples shown in the figures, no suspension element is shown. The suspension element can protrude from the main surface. The suspension element is used to suspend a battery cell on the main surface. For example, any type of material protruding from the main surface 11 or 12 can serve as a suspension element with which slipping is made more difficult by a battery cell which is arranged on the main surface. The suspension element can comprise, for example, foam, graphite and / or a metal, such as steel or aluminum. The suspension element makes it more difficult for a battery cell arranged on a main surface to slip. In the sealing segment 1 shown in FIG. 1A, a first 21 and a third section 23 of the sealing segment edge 2 run parallel to one another.

A region of the sealing segment edge 2, which connects the first 21 and the third section 23 of the sealing segment 2, comprises a second section 22 of the sealing segment edge 2, which runs orthogonally to the first 21 and third section 23. Another area of the sealing segment edge 2, which connects the first 21 and the third section 23 of sealing segment edge 2, comprises a fourth section 24 of the sealing segment edge 2, which runs parallel to the second section 22 of the sealing segment edge 2. Four straight lines, which coincide with the first, with the second, with the third and with the fourth section of the sealing segment edge 2, define a rectangle. In FIG. 1A, the straight sections 21, 22, 23, 24 merge into one another, so the sealing segment edge 2 coincides with this rectangle.

FIG. 5 shows a sealing segment battery cell unit 31 which comprises a pouch cell 40. The pouch cell is in physical contact with the main surface 11. In the example shown here, the sealing segment battery cell unit 31 has a frame 50 which bears against the main surface 11 with which the pouch cell 40 is in contact such that a channel K delimited by the pouch cell 40, sealing segment 1 and frame 50 is formed, into which a fluid can flow through the passage opening 3. The pouch cell has a surface 41 facing the viewer and electrically insulated current-conducting elements 43. With a surface running essentially parallel to the surface 41, which cannot be seen here, the pouch cell 40 bears against the main surface 11 of the sealing segment 1. The passage opening 3 is located on the left in the view shown here. The frame 50 has a rectangular profile with four circumferential surfaces 51, 53, 54. One of the four circumferential surfaces lies against the main surface 11 of the sealing element 1. The surface 53 is oriented inwards towards the pouch cell 40 and is spaced apart from the pouch cell 40. The surface 54 closes the frame from the outside. A further sealing element can rest on the surface 51, for example a main surface 112 of a further sealing element 101 according to the invention, as shown in FIG. 6 described below. FIG. 6 shows a section through a sealing segment battery cell unit 31 according to the invention further sealing segment 101 according to the invention, of which only a section is shown. The sealing segment 101 likewise has only one passage opening 103. A main surface 112 of the second sealing segment 101 bears against the frame 50 in such a way that the fluid which can flow into the channel K through the opening 3 of its sealing segment 1 flows out of the channel K through the opening 103 of the second sealing segment 101 can escape.

In the example shown here, the pouch cell 40 is arranged between the sealing segments 1 and 101 and the sealing segments 1, 101 adjoin the frame in such a way that between the surface 53, the pouch cell 40 and the sealing segments 1, 101 a communicating with the passage opening 1 Channel K is formed. The channel also communicates with the passage opening 103 of the second sealing segment 101. The course of the channel can be seen clearly in FIG.

The two through openings 3, 103 are arranged in FIG. 6 in such a way that they communicate over two sections of the cooling channel which are of essentially the same length. In the example shown here, the two sections of the cooling channel run on opposite sides of the pouch cell 40. One section of the cooling channel can be seen clearly in FIG. 6. It leads around the pouch cell on a side facing away from the current conducting elements 43. The other section of the cooling channel leads through an area which is cut off in FIG. 6. It leads along the current-conducting elements 43, which are shown in FIG. 5. It can be seen in FIG. 6 that a cooling fluid which can flow into the cooling duct through the passage opening 3 of the first sealing segment 1 must travel a distance of far more than a twentieth of the length of the segment projection outline 2 _P in the cooling duct before it can flow out of the cooling channel of this sealing segment battery cell unit 31 through the passage opening 103 of the second sealing segment 101.

The part of a traction battery shown in FIG. 7 has a plurality of sealing segment battery cell units 31, 131, 231, 331, 431. The sealing segments 101, 201, 301, 401 are each in contact with one main surface with a pouch cell and with the other main surface with another pouch cell. The pouch cells are each in contact with one surface with a main surface of a sealing segment and with the other surface with a main surface of another sealing segment.

The thickness of the sealing segments is 7 <5 mm in the figure that is not to scale.

As can be seen in FIGS. 6 and 7, the passage openings overlap in sealing segments which do not follow one another in the stacking direction. In Figure 7, the

Through openings 3, 203, 403 are arranged on a side of the battery facing the viewer, while the through openings 103, 303, 503 are arranged on a side of the battery facing away from the viewer. LIST OF REFERENCE NUMBERS

Thermally conductive sealing segments 1, 101, 201, 301, 401, 501

Sealing segment edge and segment projection outline 2 and 2p

Passage opening 3, 103, 203, 303, 403, 503 opening edge and opening projection outline 4 and 4 _P First main surface 11, 111, 511

Second main surface 12, 112

 First section of the sealing segment edge 21

Second section of the sealing segment edge 22

Third section of the sealing segment edge 23

Fourth section of the sealing segment edge 24

Sealing segment battery cell unit 31, 131, 231, 331, 431 pouch cell 40

 Surface of the pouch cell 41

Current conducting elements 43

Frame 50

 Surfaces of the frame 51, 53, 54

APF opening projection surface

Segment projection area Aps

Segment projection center of gravity SP

Polygons Pi, P ₂ , P ₃

Claims

claims 1. Sealing segment (1) having a first main surface (1 1) and a second Main surface (12), which merge into one another at the sealing segment edge (2), and at least one passage opening (3) which penetrates the sealing segment (1) from the first main surface (11) to the second main surface (12), an orthogonal projection (1 _P ) defines a segment projection outline (2 _P ), which surrounds a segment projection area A _P s, and at least one opening projection outline (4 _P ), which surrounds an opening projection (total) area A _PF , defines the sealing segment with a main surface on a projection plane, the ratio A _PF to A _{PS is} in the range from 0.001 to 0.20, all opening projection outline points are spaced from the segment projection outline (2 _P ) and lie in a circumferential segment projection area (0 _P ), the segment projection area (0 _P ) by the segment projection outline ( 2 _P ) is limited to the outside and has an all-around constant width (b), which is chosen so that the segment projection area (0 _P ) occupies 75% of the segment projection area A _PS , characterized in that the sealing segment comprises a graphite foil layer (5). 2. Sealing segment (1) according to claim 1, characterized in that the number of through openings is 1, 2 or 3. 3. Sealing segment (1) according to claim 1, characterized in that no  The opening projection outline point of an opening projection outline is closer to an opening projection outline point of another opening projection outline than 5% of the length of the segment projection outline, whereby this does not apply only with regard to the opening projection outline of grouped passage openings among one another and is considered as grouped passage openings if all  Opening projection outline points of a passage opening a distance of less than 4% of the length of the segment projection outline to one  Take the opening projection outline point of an opening projection outline of at least one other passage opening. 4. Sealing segment (1) according to claim 1, characterized in that the graphite film layer (5) extends to the edge of the sealing segment (2). 5. Sealing segment (1) according to claim 1, characterized in that the graphite foil layer (5) extends in the sealing segment (1) to a point which in the orthogonal projection (1 _P ) is closer to the segment projection surface center of gravity (Sp) than the closest opening projection outline point to the segment projection center of gravity (Sp). 6. Sealing segment (1) according to claim 1, characterized in that the graphite foil layer (5) comprises a partially compacted graphite expanded material. 7. Sealing segment (1) according to claim 1, characterized by an electrically insulating coating (6) on at least one of the main surfaces. 8. Sealing segment (1) according to claim 1, characterized in that the ratio A _PF to A _{PS is} in the range from 0.004 to 0.10. 9. Sealing segment (1) according to claim 1, characterized in that the opening projection outline (4 _P ) lies in the segment projection outline (2 _P ) such that there is an equilateral and equiangular polygon (P ₂ ), the area of which is one sixth of A _PS within the segment projection outline (2 _P ) so that the opening projection outline (4 _P ) lies completely within the polygon (P ₂ ). 10. Sealing segment (1) according to claim 1, characterized in that the opening projection outline (4 _P ) lies in the segment projection outline (2 _P ) such that none of the straight lines which intersect the opening projection outline (4 _P ) in one or more points, intersects the first segment projection outline (2 _P ) in more than two points. U. Sealing segment battery cell unit (31), comprising a battery cell (40),  characterized in that the battery cell (40) is in thermal contact with a main surface (1 1) of a sealing segment (1) according to one of claims 1 to 1 1. 12. Sealing segment battery cell unit (31) according to claim 11, characterized in that the thermal contact is formed by the battery cell (40) is in physical contact with one of the main surfaces (1 1) of the sealing segment (1), the battery cell (40) not overlapping the passage opening (3). 13. Sealing segment battery cell unit (31) according to claim 11, characterized by a frame (50) which bears against the main surface (1 1) with which the battery cell (40) is in thermal contact that a Battery cell (40), sealing segment (1) and frame (50) limited channel (K) is formed, into which a fluid can flow through the passage opening (3). 14. Sealing segment battery cell unit (31) according to claim 13, characterized by a second sealing segment (101) according to one of claims 1 to 1 1, wherein a main surface (1 12) of the second sealing segment (101) so on the frame ( 50) that the fluid that can flow into the channel (K) through the passage opening (3) of the one sealing segment (1) flows out of the channel (K) through the passage opening (103) of the second sealing segment (101) can escape. 15. Sealing segment battery cell unit (31) according to claim 14, characterized in that both passage openings (3, 103) are arranged such that they are connected via two sections (K _Ai , K _A2 ) of the channel (K) of equal length ,