KR20210005943A - Sealing segments to control the temperature of fluid cooled batteries - Google Patents

Abstract

The invention relates to a sealing segment (1) having two main faces (11, 12) and one through opening (3), in which case the orthogonal projection of the sealing segment tangent to the projection plane by one main face is , Defining a segment projection contour surrounding the segmented projection plane (A _PS ) and one or more aperture projection contours surrounding the apertured projection (full) plane (A _PF ), and A _PF The to _APS ratio lies in the range of 0.001 to 0.20, the entire aperture projection contour points are spaced from the segment projection contour and lie within the peripheral segment projection area, the segment projection area is limited to the outside by the segment projection contour, and the segment projection The area has a constant width in the circumferential direction, selected to occupy 75% of the segment projection surface A _PS , in which case the sealing segment comprises a graphite foil layer 5.

Description

Sealing segments to control the temperature of fluid cooled batteries

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

A battery module is known (US2010279152A) with a complex cooling pipeline system that forms a cooling circuit separate from the battery cell and the heat dissipation system. Such a battery module has a disadvantage in that it requires a plurality of seals that may leak over time, and on the other hand, thermal resistance exists between the heat dissipation system and the coolant. Complex and serpentine fine branch pipeline systems are complex to manufacture.

DE 10 2011 100 172 A1 describes a set of batteries comprising a stack of battery cells and cooling ribs. For liquid cooling/liquid heating, each rib comprises a cooling channel between two welded metal sheets; And a coolant inlet and a coolant outlet extending from the ribs to the ear-shaped features. Coolant is introduced through the inlet. Coolant from the first ear-shaped feature in which the inlet is located flows within the long coolant channel inside the cooling rib to another ear-shaped feature in which the outlet is located, where it is discharged out of the cooling rib. A high sealing cost occurs between the ear-shaped features of successive ribs. In order to fill the gaps between the ribs and provide a normal coolant seal, a configuration is proposed in which the ear-shaped extension is molded from sealable plastic. Alternatively, rubber seals are used.

DE 10 2011 109 306 A1 proposes a U-shaped element with cooling fluid channels. In the U-shaped element, the carrier plate to which the battery cells are attached is arranged in such a way that the fluid flowing through the cooling fluid channel flows along the surface of the carrier plate to remove heat from the carrier plate. Here, the cooling fluid channels are respectively formed between the U-shaped element and the carrier plate. That is, sealing is required substantially over the entire length of the coolant channel. In order to achieve sealing, a method of applying an adhesive over a large surface or casting a U-shaped element directly onto a carrier plate is proposed. Thus, only very complicated sealing can be possible, and there is a significant risk of leakage due to the length of the seal.

An object of the present invention is to cause driving of a vehicle, aircraft or ship such as a passenger car (BEV or HEV), and can be flexibly adapted to the space conditions existing in the vehicle, and reduce the risk of coolant discharge in a simple battery structure. It is to provide a sealing segment for the battery that achieves efficient cooling and high energy density without increasing it.

The task is a first main surface (which can be regarded as a front surface) and a second main surface (such as a rear surface) that are connected to each other at the edge of the sealing segment, and from the first main surface. 2 Solved by a sealing segment with one or more through openings penetrating the sealing segment towards the main face, in which case the orthogonal projection of the sealing segment tangent to the projection plane by the main face is the segment surrounding the segment projection plane (A _PS ) Defines the projection contour and one or more aperture projection contours surrounding the aperture projection (overall) plane (A _PF ), and A _PF The to A _PS ratio lies in the range of 0.001 to 0.20, the entire aperture projection contour points are spaced from the segment projection contour and lie within the peripheral segment projection area, the segment projection area is limited to the outside by the segment projection contour, and the segment projection The region has a constant width in the circumferential direction selected to occupy 75% of the segment projection surface A _PS , in which case the sealing segment comprises a layer of graphite foil.

Orthogonal projection means mapping the sealing segment to the projection plane such that the connecting line between a point of the sealing segment and the image of this point forms a right angle to the projection plane. This applies to each point of the sealing segment and to the connecting line leading to the image of this point. Thus, this is a special form of parallel projection. In the case of orthogonal projection, the sealing segments that are in contact with the projection plane by the main surface are aligned so that the segment projection surface A _PS is as large as possible. Depending on the shape of the main face, the main face is, for example, completely in contact with the projection plane (in the case of a flat main face), only by a portion of the main face, or only by one or more points of the main face (the main face is completely If it is not flat).

The two major faces connect to each other at the edge of the sealing segment and at the edge of the through opening. Such transitions may include end faces at the sealing segment edge and the opening edge, which can be seen for example in FIGS. 1B and 1C. The end faces typically extend approximately at right angles to the first and second major faces, for example formed by processing the planar material constituting the sealing segment by cutting, water jet cutting, laser cutting or punching. Alternatively, the edge regions may have other shapes, and for example, may include an end surface having a bend transition portion extending to the main surface.

The orthogonal projection of the sealing segment tangent to the projection plane by one major face defines the segment projection contour. The segment projection contour surrounds the segment projection plane A _PS . Orthogonal projection also defines one or more aperture projection contours. One or more aperture projection contours surround the aperture projection (overall) plane A _PF . When only one through opening exists, and thus only one opening projection contour is present, it is referred to as an opening projection surface A _PF . When a plurality of through openings exist, and thus a plurality of aperture projection contours exist, it is referred to as an aperture projection entire surface A _PF .

The segment projection surface A _PS includes an aperture projection (overall) surface A _PF because one or more aperture projection contours extend completely within the segment projection contour.

The sealing segment comprises a layer of graphite foil. The graphite foil layer extends within the sealing segment. Due to the high thermal conductivity of the in-plane graphite foil, the planar heat distribution in the sealing segment is accelerated. In addition, the compressibility of the graphite foil also provides an advantage. The graphite foil increases the sealing properties of the battery in the area between the frame and the sealing segment. The volumetric expansion of the battery cell, such as a pouch cell, abutting the sealing segment is at least partially compensated for by the graphite foil. In this respect, it is advantageous for the graphite foil layer to extend to the sealing segment edge. It is also preferred that the graphite foil layer extends within the sealing segment, to a point lying closer to the center of the segment projection surface than the aperture projection contour point closest to the center of the segment projection surface in the orthogonal projection. Then at this point the volume change of the battery cell can be at least partially compensated by the graphite foil.

In a very particularly preferred sealing segment according to the invention, the projection surface of the graphite foil in an orthogonal projection occupies at least 90%, in particular at least 95%, for example at least 98% of the segment projection surface A _PS .

The graphite foil layer may be a synthetic graphite foil layer formed based on a polymer. Or preferably the graphite foil layer comprises partially compressed graphite expansion.

The production of graphite foil layers comprising partially compressed graphite expansion products is generally known. As is known, the graphite foil layer can be prepared by treating graphite with a specific acid, in which case a graphite salt is formed by an acid anion intercalated between the graphite layers. The graphite salt is then expanded by exposure to a high temperature, for example 800°C. For example, for the production of expanded graphite having a worm-like structure, graphite such as natural graphite is usually mixed with an intercalate such as nitric acid or sulfuric acid, for example 600° C. to 1200° C. It is heat treated at a high temperature (see DE10003927A1).

Subsequently, the graphite expansion product obtained upon expansion is compressed into graphite foil. A method for producing graphite foils is described for example in EP 1 120 378 B1. In addition, DE 10 2012 202 748 A1 describes a method for making graphite foils.

Compression can be controlled so that a very strong graphite foil is obtained. If the graphite expansion product is compressed only slightly (for example to a density in the range of 0.2 to 0.7 g/cm 3 ), a relatively flexible graphite foil layer is obtained, for example when the thickness is 0.5 mm. When compressed to a higher density, for example 1.5 to 1.9 g/cm 3, the obtained graphite foil layer is substantially inflexible at the same thickness and in the form of a plate.

The sealing segment preferably has an electrically insulating coating on at least one major surface. This coating can be formed, for example, of plastic, preferably polyethylene terephthalate (PET) or PTFE, such as expanded PTFE (ePTFE). This has the advantage that unwanted electrical charging of the sealing segment is avoided even in case of damage to the battery cell.

The electrically insulating coating can cover the two major faces substantially completely, for example up to 90% or more. The edge of the through opening can be completely covered by an electrically insulating coating. This has the advantage that the fluid flowing through the through opening and used for cooling cannot penetrate into the sealing segment in the opening area. In this case, the sealing segment is kept longer and has to be replaced less frequently.

In one particularly preferred embodiment, the sealing segment is made of a flat material containing expanded graphite as specified in WO 2011/101391 A1. Due to this, excellent thermal conductivity in the surface direction can be achieved, and at the same time, the possibility of matching for the volume change of the battery cell can be achieved in both directions (volume expansion direction and volume reduction direction). In addition, the flat material of the sealing segment, containing graphite, can be particularly well matched to a wide variety of battery cell types.

In one embodiment of the invention, the sealing segment has a density of 0.6 to 1.9 g/cm 3, preferably 0.7 to 1.4 g/cm 3 and particularly preferably 0.9 to 1.1 g/cm 3, such as advantageously of 1.0 g/cm 3 Have a density In another embodiment of the invention, the sealing segment is in the surface direction of 120 to 500 W/(m K), preferably 130 to 480 W/(m K), particularly preferably 250 to 450 W/(m K). It has thermal conductivity. Thermal conductivity is determined using the Ångstroem'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 on the entire surface in the thickness direction. Has. The springback is determined according to sections 9.1, 9.2 and 9.2.1 of DIN 28090-2:1995-09. It has been found that this effectively prevents unwanted outflow of cooling fluid in the area where the sealing segment abuts the frame. Further, in this case, a material having a high coefficient of thermal expansion may also be used for a frame such as a plastic frame based on a polymer. The springback of the sealing segment compensates for distortion of the frame associated with localized temperature fluctuations, thereby ensuring a high level of sealing, for example even at vehicle start-up at low external temperatures.

This enables the desired local compression at the sealing segment edges abutting the frame when securing the sealing segment between frames. This makes unwanted cooling fluid outflow more difficult. In this case, the frame can be manufactured with higher manufacturing tolerances, and the unevenness is compensated very well by the compression sealing segments. When injection molding plastic frames, relatively high manufacturing tolerances are tolerated as desired for higher manufacturing efficiency. Thus, the sealing segments that can be used according to the invention enable particularly efficient battery production, and are preferably used with plastic injection molded frames.

Preferably, the sealing segment may consist of compressed graphite expansion. In an alternative embodiment, the sealing segment may consist of a mixture formed prior to compression, ie a mixture composed of graphite expandables and plastic particles uniformly mixed throughout. In another alternative embodiment, the sealing segment may be impregnated at the surface of the sealing segment or into the core region by means of a plastic provided after compression. By means of such embodiments, a sealing segment can be formed which is preferably very shape stable and easy to handle. Preferably, thermoplastic resins, thermosetting resins or elastomers can be used as plastics, in particular fluoropolymers, PE, PVC, PP, PVDF, PEEK, benzoaxine and/or epoxy resins can be used as plastics.

In order to enable particularly good heat transfer from the battery cell to the sealing segment, the sealing segment can be matched to the outer contour of the battery cell. For example, the sealing segment may have a groove for accommodating a portion of the outer surface of the battery in a form-fitting manner, in which case the groove enables close contact over a large area as possible of the battery to the main surface of the sealing segment. In order to be able to do so, it may be formed specially for accommodating portions of a specific cylindrical or prismatic battery.

In one preferred sealing segment, one or two major faces are substantially flat. This has the advantage that efficient heat transfer is ensured by allowing the substantially flat surface of the pouch cell to contact the heat exchange surface.

In order not to interfere with the volumetric expansion that only occurs during operation of the battery cell, such as a pouch cell, the sealing segment and the battery cell are preferably in the idle and discharged state of the energy storage device, and the sealing segment is only weakly in the thickness direction, preferably They can be pressed together so that they are compressed only by up to 1% based on their initial thickness.

The number of through openings is not limited. The number of through openings may be 1, 2, 3, 4, 5 or 6, preferably 1, 2, 3, 4 or 5, more preferably 1 It may be dogs, two, three or four, particularly preferably one, two or three, for example one or two. In one very particularly preferred sealing segment according to the invention the number of through openings is one.

All aperture projection contour points are spaced apart from the segment projection contour.

If the sealing segment has more than one through opening, the through openings are preferably grouped close to each other or lie apart from each other.

Grouping the through openings close to each other has the advantage that turbulence of the cooling fluid is promoted even at a low flow rate during perfusion. This applies in any case in comparison with a single through opening whose aperture projection surface corresponds to the summed aperture projection surface of the grouped through faces.

On the other hand, if a plurality of through openings (or groups of through openings) are present, these through openings should be as far apart from each other as possible. The reason is that, ultimately, only two through openings in the subsequent sealing segments in the battery cell stack so that the cooling fluid flows along the surface of these sealing segments over the longer intervals between the sealing segments. This is because it offers the possibility of placing it in the center of each space. This is because the invention makes effective cooling possible, in particular, as the cooling fluid is guided as intended along the sealing segment surface.

The preferred spacing of through openings specified in the preceding three paragraphs can be defined as follows:

Any aperture projection contour point of one aperture projection contour is closer to an aperture projection contour point of another aperture projection contour than an interval of less than 5%, in particular 8%, particularly preferably 10%, such as 15% of the length of the segment projection contour. Not placed. This does not apply only in relation to the aperture projection contour of the through apertures grouped together. If the total aperture projection contour point of one through opening takes a spacing of less than 4% of the segment projection contour length to the aperture projection contour point of the aperture projection contour of one or more other through openings, the through openings are considered grouped. The opening projection contour point is understood to mean a point at which an opening projection contour is formed, or when a plurality of through openings exist, a point at which opening projection contours are formed.

All aperture projection contour points lie inside the peripheral segment projection area.

The peripheral segment projection area is externally limited by the segment projection contour. The peripheral segment projection area has a constant width in the peripheral direction. This width means that the peripheral segment projection area is 75%, preferably 65%, more preferably 55%, particularly preferably 45%, very particularly preferably 35%, such as 30% of the segment projection surface A _PS Is chosen to occupy. As exemplarily shown in FIGS. 4A to 4D, a peripheral segment projection area having a constant width may be specified for each segment projection contour.

That is, according to the invention, the through opening(s) are in one outer area of the sealing segment, defined using the orthogonal projection and the peripheral segment projection area. Due to this, the inner area of the sealing segment surrounded by the outer area can be used for face-to-face thermal contact between the battery cell(s) and the main side(s).

The battery composed of sealing segments according to the invention can be flexibly adapted to the spatial conditions present in the vehicle. The sealing segment enables a stack-like structure of the battery, for example as shown in FIG. 7. In this case, the shape of the sealing segments and the length of the individual stacks can be selected substantially freely, so that the available hollows for the traction battery in a particular vehicle type can be utilized as fully as possible.

For example, the ridges between passenger car seats, such as the cardan tunnel, have a preset shape and cannot be arbitrarily extended into the interior of the cabin. In order to make use of the mounting space present there as completely as possible, a battery can be constructed, for example based on ladder-shaped sealing segments. In addition, sealing segments having a segment projection surface of substantially rectangular, triangular, elliptical or circular can also be considered.

When a plurality of batteries in different locations are to be arranged directly side by side or stacked up and down, the cavities between the batteries are generally undesirable, because such spaces are difficult to utilize otherwise. In this case, a sealing segment having a substantially rectangular segment projection surface is recommended, since a stack consisting of such sealing segments can be arranged side by side with little undesirable cavities.

With the sealing segment according to the invention, efficient cooling and high energy density are achieved even with a simple design. By means of the various elements of the battery which can be composed of the sealing segments according to the invention, the sealing segments cause a synergistic effect as described in the following paragraphs.

The sealing segments can be connected directly to the frame to achieve sealing, in which the sealing segments can be clamped between the frames (seal function). In addition, the sealing segments place the battery cells at a desired location in the cell stack (positioning function). These sealing segments enable defined point-like penetration of the cooling fluid through the through openings and limit the channel sections extending between the through openings in the stack direction (fluid guiding function). At the same time, excess heat of the battery cell is transferred directly to the sealing segments. This heat is also distributed within the sealing segment into an outermost area, in which one or more major faces of the sealing segment are brought into contact with the cooling fluid, and heat is transferred to the cooling fluid (heat conduction function).

If the sealing segments are firmly fixed between the frames, the battery behaves like a single fixed body that can be fixed in the vehicle via the frame (positioning function). By the frame forming the walls of the cooling channel, it is possible for the cooling fluid to flow along the surface of the frame within the cooling channel (fluid guiding function).

In the present invention, battery cells are used not only to supply electrical energy, but at the same time limit the cooling channel. The battery cells contribute to causing the fluid to be guided along the battery cell (fluid guiding function). This simultaneously results in efficient cooling, since the cooling fluid flows along the cell surface.

By means of the sealing segment, there is no need for parts that have also been required according to the prior art. The cooling channel extending over the entire length of the stacked structure of the battery and surrounding the individual battery cells, when using the sealing segment according to the present invention, does not require a separate dedicated component, and the frame, sealing segment And a battery cell (see in particular FIGS. 3, 4 and 5). This ensures a particularly simple design.

In this way, at the same time very efficient cooling of the battery cells is achieved. Excess heat is transferred from the battery cell via the sealing segment to the cooling fluid as described above (first heat path). Additionally, since the cooling channel defined by the sealing segments and their through openings flows along the battery cell, excess heat is transferred directly from the battery cell to the cooling fluid (second heat path). Since heat is leaked from the battery cells through a plurality of heat paths at the same time, sufficient cooling is possible with a relatively small volume of cooling fluid flow or with a less cold cooling fluid. In this respect, the sealing segment is used according to the invention for temperature control. Thus, relatively less cooling costs are required. In addition, the cooling fluid can be used for heat absorption without interruption when passing from one battery cell to the next. The sealing segments according to the invention can be arranged so as to allow a continuous flow around the battery cell, whereby the through openings can also be positioned in such a way. Through this, the dead volume in which the cooling fluid for absorbing heat from the battery cell cannot be used is limited to a minimum. The sealing segment according to the invention thereby ultimately allows a very economical use of the heat absorption capacity of the cooling fluid, which allows the use of very small coolant volumes.

Thus, a very high energy density is derived with respect to the entire battery including the coolant.

The ratio of A _PF to A _PS lies in the range of 0.001 to 0.20, preferably 0.003 to 0.175, more preferably 0.004 to 0.15, particularly preferably 0.004 to 0.125. When the ratio of these areas is much smaller, the flow resistance of the cooling fluid becomes too large even in a short stack with only a few sealing segments. Fluid delivery devices such as pumps, for example, will consume too much energy to deliver a sufficient amount of cooling fluid through the stack. If the area ratio is much larger, the heat dissipation from the battery cell is excessively deteriorated, because in this case an excessively large proportion of the available area for heat exchange (heat conduction in the graphite foil layer) is through openings Because it is used by (s).

The shape of the sealing segment is not limited. In principle, any shape can be considered. Special shapes may be required to form a traction battery that fits perfectly into a specific cavity in a vehicle. However, in general a shape with short sealing segment edges is preferred, since such shape further reduces the likelihood of cooling fluid drainage and sealing segment expansion due to cooling fluid absorption through the end faces. For example, the length of the segment projection contour exceeds the perimeter of a rectangle having an area corresponding to the segment projection plane A _PS by at most 65%, preferably by at most 30% and particularly preferably by at most 10%.

In a preferred manner, the segmented projection contour does not include concave sections. The concave section is such that one straight line intersects the segment projection contour at two or more points, and the partial area of the segment projection surface contained between this straight line and the segment projection contour is at least 3% of A _PS . It exists when it can be placed within.

It is less preferred if the through opening lies in the peripheral region of the sealing segment according to the invention. Orthogonal projections of the less preferred sealing segment, with through openings in the peripheral lugs projecting from the regular bottom surface, are shown in FIGS. 3A and 3B. Preferred sealing segments according to the invention are distinguished from the sealing segments by means of a polygon used to define the preferred position of the through opening. According to the invention, equilateral and conformal polygons, such as an area of which are equal to one eighth, generally one sixth, preferably one fifth, more preferably one quarter and particularly preferably of A _PS It is preferred if the aperture projection contour lies within the segment projection contour in such a way that a third square can be aligned inside the segment projection contour, but the aperture projection contour lies entirely inside the polygon.

In accordance with the invention the position of the less preferred through opening in the sealing segment can be specified using a polygon or a square, as well as a straight line intersecting the opening projection contour at one or more points instead of a polygon or as a complement of a polygon It can also be specified using a group. Preferably, the aperture projection contour lies within the segment projection contour such that a straight line intersecting the aperture projection contour at one or more points does not intersect the first segment projection contour at two or more points.

If the through opening is not located in the peripheral region of the sealing segment, the flow resistance is reduced because it is not necessary to be guided to the peripheral region in order for the cooling fluid to flow through the through opening and through the sealing segment.

According to the invention, the distance from the aperture projection contour to the segment projection contour does not anywhere below reach 50%, preferably 75% and particularly preferably 100% of the sealing segment thickness. This has the advantage that the area of the sealing segment extending between the through opening and the segment edge is generally sufficiently wide and can be clamped between the frames without twisting or performing other types of disengagement movements upon pressing. This reduces the risk of unwanted coolant emissions. The distance from the aperture projection contour to the segment projection contour is measured in the orthogonal projection. The sealing segment thickness is determined according to DIN EN ISO 5084 (October 1996). The sealing segment thickness is measured in the orthogonal projection direction. A pressure stamp with a circular test face is used, and the diameter of this pressure stamp corresponds to the shortest distance from the aperture projection contour to the segment projection contour, in this case the segment projection contour is, for each thickness measurement, the segment projection contour from the aperture projection contour. When measuring individual distances to, the following line is arranged to divide the test surface into two equally sized halves. The sealing segment thickness is determined at a pressure of 0.1 kPa, and this pressure indication relates to the circular test side of the pressure stamp.

Preferably, at least one first and third sections of the sealing segment edge extend parallel to each other. In this case, the advantage is derived that the sealing segment can be guided very easily between two parallel extending frames, which makes it possible to replace the individual component parts of the battery, such as the sealing segment and the battery cell attached to it as necessary. In particular, it is possible very simply.

Further, at least one region of the sealing segment edge connecting the first section and the third section of the sealing segment edge defines a second section of the sealing segment edge extending at right angles to the first section and the third section of the sealing segment edge. It is preferable to include.

Another region of the sealing segment edge connecting the first section and the third section of the sealing segment edge includes a fourth section of the sealing segment edge extending parallel to the second section of the sealing segment edge.

Preferably, the sealing segment edge has four or more straight sections, and four straight lines coincident with these sections define a square.

Preferably the segment face does not protrude above the rectangle. For example, a straight line coinciding with the first, second, third and fourth sections of the sealing segment edge defines one rectangle, and the segment face does not project above this rectangle. This ensures that the segment edges are short compared to the segment faces, whereby the risk of unwanted discharge of cooling fluid at a given cooling capacity is relatively low, and less hazardous motor vehicle operation is assured.

The sealing segment can meet the following conditions.

d ₁ = x·d ₃ , and

d ₂ = y·d ₄ .

In the above condition, d ₁ represents the distance from the opening edge to the first section of the sealing segment edge, d ₂ represents the distance from the opening edge to the second section of the sealing segment edge, and d ₃ is the sealing segment from the opening edge. Represents the distance to the third section of the edge, d ₄ represents the distance from the opening edge to the fourth section of the sealing segment edge, x represents a number in the range of 0.25 to 4, and y is in the range of 3 to 50 Represents a number. This ensures that the through opening lies close to the second section and far away from the fourth section.

Preferably, the distance from the first section to the third section is greater than the distance from the second section to the fourth section.

The invention also relates to a sealed segment battery cell unit comprising a battery cell, in which case the battery cell is in thermal contact with the main surface of the sealing segment according to the invention. Thermal contact may be formed such that the battery cell is in physical contact with one of the major faces of the sealing segment, or with an electrically insulating coating disposed on the major face, in which case the battery cell does not overlap with the through opening. . If the aperture projection contour point is not placed within the projection contour of the battery cell in the orthogonal projection, the battery cell does not overlap the through opening.

The battery cell is preferably selected from prismatic cells, pouch cells and cylindrical cells. A particularly preferred sealed segment battery cell unit is a sealed segment pouch cell unit. That is, a particularly preferred battery cell is a pouch cell.

Battery cells, such as pouch cells, are not limited in terms of cell chemistry. Preferably, the reversible oxidation of lithium to Li ⁺ cations is involved in the current supply.

Preferably, the pouch cells are substantially flat and have a front side and a rear side extending parallel to each other. The front and rear surfaces occupy at least 50%, such as at least 60%, preferably at least 70%, of the total surface of the part that closes the pouch cell to the outside.

Preferably the frame is in thermal contact with the battery cell (or electrical insulation) so that a channel is formed which is limited by the battery cell, the sealing segment and the frame, and through which fluid can enter through the through opening. Adjacent to the coating).

Preferably the channel is annular, ie the projection contour of the battery maintains a defined distance to the projection contour of the frame in an orthogonal projection. Preferably, each point of the projection contour of the battery maintains a distance of up to 20% of the length of the segmented projection contour to the projection contour of the frame, for example up to 10% of the length of the segmented projection contour. Further, preferably each point of the projection contour of the battery is at least 0,1% of the length of the segment projection contour relative to the projection contour of the frame, for example at least 0.5% of the length of the segment projection contour. This ensures that the cooling fluid can flow through even a particularly narrow area of the cooling channel unobstructed, while at the same time, the cooling fluid flow is not stopped in a particularly large channel area. This increases heat transport, which ultimately increases the energy density of the battery and/or the life of the battery cell.

A particularly preferred sealing segment battery cell unit comprises a second sealing segment according to the invention, in which case the main face of the second sealing segment is a second fluid through which a fluid can enter the channel through the through opening of one sealing segment. Abuts the frame so that it can be discharged out of the channel through the through opening of the sealing segment.

The first and second sealing segments are generally tightly abutting the pouch cell so that the pouch cell does not slip out between the sealing segments.

Preferably, in an orthogonal projection, the segment projection contour of the second sealing segment coincides with the segment projection contour of the first sealing segment. This, the second, at least 95% of the segment, the projection surface of the seal segment, preferably at least 98%, at least 95% of the segment plane, A and segment plane (A _PS) to (A _PS), preferably at least 98% of the 2 means that the sealing segment belongs to the segment projection plane.

In an orthogonal projection, each aperture projection surface of the first sealing segment maintains a generally arbitrary distance to each aperture projection surface of the second sealing segment. This distance is preferably at least one fifty, particularly preferably at least one twenty, such as at least one tenth of the length of the segment projection contour of the first sealing segment.

Preferably, the through opening of the first sealing segment and the through opening of the second sealing segment are connected via two equal length sections of the channel. The length of the channel section is determined in the orthogonal projection, for this purpose an auxiliary straight line passing through the center of both sides of the aperture projection surfaces is arranged. At this time, projection of one section of the channel proceeds from one side of the auxiliary straight line, and projection of the other section of the channel proceeds from the other side of the auxiliary straight line. The length of one section of the channel is the shortest connection from the aperture projection contour of one sealing segment to the aperture projection contour of the other sealing segment that does not intersect the projection contour of the battery cell. If the relatively longer section is at most 50%, preferably at most 15% longer than the relatively shorter section, then two equal length sections are provided. This promotes the transfer of approximately the same amount of heat to the cooling fluid in the entire portion of the outer region of the sealing segment, whereby a uniform heat dissipation from all portions of the cell is achieved. At this time, so-called hot spots damaging the battery cells are less pronounced. Ultimately, this extends the life of the battery cells and the life of a traction battery composed of battery cells.

The sealing segment bends when the volume of the battery cell that can adhere to the sealing segment expands, and when the volume of the battery cell decreases, the sealing segment bends for a safe thermally conductive connection of the sealing segment to the battery cells. It can be formed to expand. In order not to interfere with the volumetric expansion that only occurs during operation of the battery cell, the sealing segment and the battery cell can preferably be pressed together in the non-operating state of the energy storage device, whereby the sealing segment of the sealing segment(s) is initially It is compressed only weakly in the thickness direction based on the thickness, preferably by at most 1%.

The sealing segment according to the invention is suitable for temperature control in completely different batteries. The sealing segment according to the invention is particularly well suited for temperature control in high performance batteries, for example traction batteries in BEVs or HEVs. BEV refers to a vehicle for transporting people and/or objects, driven by an electric motor and drawing electrical energy required for forward movement from a traction battery. HEV refers to a vehicle for transporting people and/or objects, driven by an electric motor and another energy converter, and drawing electrical energy required for forward movement from some traction batteries.

In order that no additional suspension element is required, it is possible to clamp the battery cell between the sealing segments according to the invention, while at the same time aligning the battery cell with a current conducting element. The reason this is an advantage is that the battery can be assembled in a particularly simple way, that is to say from a few simple parts.

Alternatively, a suspension element can be arranged on the first and/or second main face, or in an electrically insulating coating affixed to the main face(s), in which case the suspension element protrudes from the main face, for example do. Suspension elements may include, for example, foam materials, graphite and/or solid metals (eg steel or aluminum). With this suspension element, it becomes more difficult for the battery cells placed on the main surface or the electrically insulating coating to slip out.

The suspension element may be a bracket on which the battery cell is suspended between the sealing segments according to the invention. The bracket can, for example, extend into an area lying outside the frame with current conducting elements. The bracket may extend around a battery cell, such as a pouch cell, disposed between the two sealing segments.

Also a subject of the invention is a traction battery comprising a stack of sealed segment battery cell units according to the invention.

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

Electrically non-conductive means that the liquid does not conduct current. The conductivity measured at each 25°C is 10 ^-8 S·cm ^-1 at the maximum, and the electrical resistivity is 10 ⁸ Ω·cm. The electrical resistivity is measured according to DIN EN 60247:2004.

When an electrically non-conductive liquid is used as a cooling fluid, there is an advantage in that a short circuit is not caused in case of damage to the battery cell and thermal runaway in some cases.

The electrically non-conductive liquid preferably contains a fluorinated organic compound, such as a fully fluorinated organic compound or a partially fluorinated organic compound, such as a fully fluorinated ketone or a partially fluorinated ether. The boiling point of the compound, measured at a pressure of 1 bar, may for example lie in the range of 45 to 150°C, preferably in the range of 55 to 100°C. In the case of a fully fluorinated ketone, a seven-fold fluorinated isopropyl group and a five-fold fluorinated ethyl group may be attached to the keto carbon.

Further details and advantages of the present invention refer to the description of the following embodiments based on the drawings.

1a shows a sealing segment according to the invention.
1B and 1C are two different perspective views of the corner area of the sealing segment shown in FIG. 1A (the corner area is indicated by a rectangle in the upper right corner of FIG. 1A).
2, 3a, 3b and 3c are orthogonal projections of a sealing segment according to the invention.
4A to 4D are diagrams illustrating a definition of a peripheral segment edge region in the example of the orthogonal projection of FIG. 3B.
5 is a view showing a sealed segment battery cell unit according to the invention.
6 is a cross-sectional view of a sealed segment battery cell unit according to the invention.
7 is a partial view of a traction battery composed of sealed segment battery cell units according to the invention.

1A shows a sealing segment 1 for temperature control of a fluid cooled battery. The sealing segment 1 has a first major side 11 and a second major side 12. In addition, the sealing segment 1 has a through opening 3 penetrating the sealing segment from the first main face 11 toward the second main face 12. The second main surface 12 is not visible in FIG. 1A, because as can be seen from the perspective view shown in FIG. 1C, the second main surface faces away from the observer, and with respect to the first main surface 11 This is because it extends substantially parallel. In the perspective view shown in Fig. 1C, both main surfaces face the observer.

The two main faces 11 and 12 connect to each other at the sealing segment edge 2 and at the opening edge 4. Figure 1b shows, for example, how the major faces 11, 12 can connect to each other at the sealing segment edge. Here, the edge 2 forms a surface extending substantially perpendicular to the main surfaces 11 and 12. However, all other types of transitions of the major faces 11 and 12 in the edge region can also be considered, for example transitions through curved edges. The opening edge 4 surrounds the through surface.

The sealing segment shown in FIG. 1A consists of a graphite foil 5 formed substantially of compressed graphite expansion, partially compressed to a density of 1.5 g/cm 3. That is, the sealing segment comprises a layer of graphite foil.

The position of the through opening 4 in the sealing segment is defined via an orthogonal projection. This is shown by the orthogonal projections 1 _P shown in Figs. 2, 3a, 3b, 3c as an example for four different sealing segments not shown, where the two main faces 11 and 12 are Each is flat and extends substantially parallel to each other and to a projection plane not shown in the figure. In Figs. 2, 3a, 3b and 3c an individual segment projection contour 2 _P is shown, which likewise surrounds the individual segment projection surface A _PS shown in the figure. Further, the aperture projection contour _4P and the aperture projection surface A _PF each surrounded by the outline are shown, respectively. In these examples, the ratio of A _PS to A _PF is not less than 0.004 and does not exceed 0.10, and in all examples, all points of the aperture projection contour 4 _P (i.e., all aperture projection contour points) are segmented projection contours ( It can be seen that it is separated from 2 _P ).

Further, in the projections shown in FIGS. 2, 3A, 3B and 3C, all aperture projection contour points lie within the peripheral segment projection area 0 _P , and this peripheral segment projection area has a constant width b in the peripheral direction. ) to have, it is limited to the outside by a projection contour segment _(P 2). In Fig. 2, a segment projection area 0 _P having a constant width b in the peripheral direction is indicated by crossed hatches. The width b was selected so that the segmented projection area O _P occupied 75% of the segmented projection surface A _PS .

Whether all aperture projection contour points are within the peripheral segment projection area O _P is determined as follows (the following steps are shown in Figs. 4A-4D for the orthogonal projection shown in Fig. 3B):

First, a point X of the aperture projection contour which is farther away from the segment projection contour or at the same distance from all other points of the aperture projection contour is determined (see X in Fig. 4A). If necessary, if the sealing segment is provided with a plurality of through openings, all points of the plurality of aperture projection contours have to be considered.

-Then the distance of the point X from the segment projection contour is measured (see double arrows in Fig. 4b).

-A line holding the distance to the segmented projection contour is drawn inside the segmented projection contour. Such a line can be illustrated as a plurality of circles, with its center lying on the segment projection contour, for example using a compass and its radius corresponding to the distance shown in Fig. 4b (see Figs. 4c, 4d). The arrow pointing to the left indicates the peak to the left of the line, which peak can be clearly seen in FIG. 4D.

-Then, the ratio of the plane to the segment projection surface contained between the line and the segment projection contour is determined. If the ratio of the two sides is at most 0.75, then the sealing segment according to the invention is present. From Fig. 4D, it can be easily seen that the ratio is less than 0.75 in the case shown there.

In the orthogonal projections shown in Figs. 2, 3A, 3B and 3C, the length of the segment projection contour 2 _P only slightly exceeds the periphery of the square having an area corresponding to the segment projection surface A _PS . The segment projection plane A _PS has a rectangular shape in FIG. 2, in which case the ratio of the length to width of this rectangle is 2:3. For a rectangle with a length to width ratio of 2:3, the edges are only about 2% longer than for a square with the same area. In Fig. 3b, the segment projection plane A _PS has two rectangular shapes of different sizes in contact with each other, and the ratio of length to width is 5:6, respectively, in which case the area of one rectangle is 15 times the area of the other rectangle. Corresponds to. In this case, the segment projection contour 2 _P is about 28% longer than in a square with the same area.

2, the segment projection outline (2 _P) opening projection contours (4 _P) inside is, in one-sixth of the opening projected onto the contour (4 _P) is such that fully placed inside the square (P _2), A _PS A square P ₂ with the corresponding area is laid in such a way that it is aligned inside the segment projection contour 2 _P. Square having an area that corresponds to one-fifth of the A _PS (P _3), and a square having an area corresponding to one-eighth of the A _PS (P ₁₎ is also aligned with the same. The orthogonal projections shown in FIGS. 3A and 3B do not satisfy the above condition, as can be seen from the squares shown in these figures.

Suspension elements may be arranged on the first main surface 11 and/or the second main surface 12. In the examples shown in each figure, no suspension element is shown. The suspension element can protrude from the main face. Suspension elements are used to suspend battery cells on the main surface. For example, any type of material protruding from the main surface 11 or 12 can be used as the suspension element, which makes it difficult for the battery cells disposed on the main surface to slip out. The suspension element may comprise, for example, a foam material, graphite and/or a metal such as, for example, steel or aluminum. This suspension element makes it difficult for the battery cells arranged on the main surface to slide off.

In the sealing segment 1 shown in FIG. 1A, the first section 21 and the third section 23 of the sealing segment edge 2 extend parallel to each other.

The area of the sealing segment edge 2 connecting the first section 21 and the third section 23 of the sealing segment 2 extends at right angles to the first section 21 and the third section 23 And a second section 22 of the sealing segment edge 2. Another area of the sealing segment edge 2 connecting the first section 21 and the third section 23 of the sealing segment edge 2 is relative to the second section 22 of the sealing segment edge 2 It comprises a fourth section 24 of the sealing segment edge 2 extending in parallel. Four straight lines coincident with the first, second, third and fourth sections of the sealing segment edge 2 define one rectangle. In FIG. 1a the straight sections 21, 22, 23, 24 connect to each other, so that the sealing segment edge 2 coincides with the rectangle.

5 shows a sealed segment battery cell unit 31 comprising a pouch cell 40. The pouch cell is in physical contact with the main surface 11. In the example shown in this figure, the sealing segment battery cell unit 31 is limited by the pouch cell 40, the sealing segment 1 and the frame 50, through which the fluid is passed through the through opening 3 to the inside thereof. A frame 50 in contact with the main surface 11 in contact with the pouch cell 40 is provided so that a channel K through which the flow can be introduced is formed. The pouch cell has a face 41 facing the viewer and an electrically insulated current conducting element 43. The pouch cell 40 abuts the main face 11 of the sealing segment 1 by means of a face not visible in this figure, extending substantially parallel to the face 41. The through opening 3 is located on the left side in the figure shown here. Frame 50 has one rectangular profile with four peripheral surfaces 51, 53, 54. One of the four peripheral surfaces abuts the major surface 11 of the sealing element 1. The surface 53 is oriented inwardly toward the pouch cell 40 and is spaced apart from the pouch cell 40. Surface 54 closes the frame outward. The surface 51 can be abutted by another sealing element, for example a major surface 112 of another sealing element 101 according to the invention, as in FIG. 6 described below.

6 shows a cross section of a sealed segment battery cell unit 31 according to the invention. This battery cell unit comprises another sealing segment 101 according to the invention, in which only one section of this sealing segment is shown. The sealing segment 101 likewise has only one through opening 103. The main surface 112 of the second sealing segment 101 is the second sealing segment 101 with a fluid that can flow into the channel K through the through opening 3 of the one sealing segment 1. It is in contact with the frame 50 so that it can be discharged to the outside of the channel K through the through opening 103 of the.

In the example shown in this figure, the pouch cell 40 is disposed between the sealing segments 1 and 101, the surface 53, the sealing segments 1, 101, the pouch cell 40 and the sealing It is connected to the frame so that a channel K communicating with the through opening 1 is formed between the segments 1 and 101. The channel also communicates with the through opening 103 of the second sealing segment 101. In FIG. 6, the channel extension can be clearly seen because only the section of the sealing segment 101 including the through opening 103 and a portion of the main surface 111 is shown.

In FIG. 6 the two through openings 3, 103 are both arranged so that they communicate through two sections of substantially the same length of the cooling channel. In the example shown in this figure, the two sections of the cooling channel extend on oppositely disposed sides of the pouch cell 40. One section of the cooling channel can be clearly seen in FIG. 6. This section extends around the pouch cell on the side facing away from the current conducting element 43. Another section of the cooling channel passes through the area shown by cutting in FIG. 6. This section is guided along the current conducting element 43 shown in FIG. 5.

In FIG. 6, the cooling fluid which can be introduced into the cooling channel through the through opening 3 of the first sealing segment 1, through the through opening 103 of the second sealing segment 101, is the sealing segment battery cell. It can be seen that before it can be discharged out of the cooling channel of the unit 31, it has to pass a section in the cooling channel that is much longer than one twentieth the length of the segment projection contour 2 _P.

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

The thickness of the sealing segment in FIG. 7 not to scale is less than 5 mm.

As can be seen in FIGS. 6 and 7, through openings in sealing segments that are not continuous with each other in the lamination direction overlap. In Fig. 7, the through openings 3, 203, and 403 are arranged on the side of the battery facing the observer, while the through openings 103, 303, 503 are arranged on the side of the battery facing away from the observer.

Thermally conductive sealing segment 1, 101, 201, 301, 401, 501
Sealed segment edge and segment projection contour 2 and 2 _P
Through opening 3, 103, 203, 303, 403, 503
Aperture edges and aperture projection contours 4 and 4 _P
Week 1 Scenes 11, 111, 511
Week 2, pages 12, 112
First section 21 of the sealing segment edge
Second section 22 of the sealing segment edge
Third section 23 of the sealing segment edge
4th section 24 of the sealing segment edge
Sealed segment battery cell units 31, 131, 231, 331, 431
Pouch cell 40
Surface of the pouch cell 41
Current conducting element 43
Frame 50
Frame surface 51, 53, 54
Aperture projection surface A _PF
Segment projection plane A _PS
Center of the segment projection plane S _P
Polygons P ₁ , P ₂ , P ₃

Claims (15)

The first and second main faces (11) and second main faces (12), which are connected to each other at the sealing segment edge (2), and through the sealing segment (1) from the first main face (11) to the second main face (12). A sealing segment (1) with at least one through opening (3),
An orthogonal projection (1 _P ) of the sealing segment tangent to the projection plane by the main face, one surrounding the segment projection contour (2 _P ) and the aperture projection (total) plane (A _PF ) surrounding the segment projection plane (A _PS ) Define the above aperture projection contour ( _4P ),
A _PF The ratio of _PS to A lies in the range of 0.001 to 0.20,
The entire aperture projection contour points are spaced apart from the segment projection contour (2 _P ) and lie within the peripheral segment projection area (O _P ),
The segment projection area (O _P ) is externally limited by the segment projection contour (2 _P ), and the segment projection area (O _P ) is selected to occupy 75% of the segment projection surface (A _PS ), with a constant width ( In the sealing segment (1) with b),
Sealing segment (1), characterized in that the sealing segment comprises a layer of graphite foil (5). The sealing segment (1) according to claim 1, characterized in that the number of through openings is one, two or three. The method of claim 1, wherein no aperture projection contour point of one aperture projection contour lies closer to the aperture projection contour point of another aperture projection contour than a spacing less than 5% of the segment projection contour length, which It does not apply only in relation to the aperture projection contour; The through openings are considered grouped if the total aperture projection contour point of one through opening takes a spacing of less than 4% of the segment projection contour length to the aperture projection contour point of the aperture projection contour of one or more other through openings; Sealing segment (1), characterized in that. The sealing segment (1) according to claim 1, characterized in that the graphite foil layer (5) extends to the sealing segment edge (2). The segment projection surface according to claim 1, wherein the graphite foil layer (5) extends within the sealing segment (1), but in an orthogonal projection (1 _P ) than the aperture projection contour point closest to the center of the segment projection surface (S _P ). Sealing segment (1), characterized in that it extends to a point lying closer to the center (S _P ). The sealing segment (1) according to claim 1, characterized in that the graphite foil layer (5) comprises partially compressed graphite expansion. The sealing segment (1) according to claim 1, characterized in that at least one of the major faces is provided with an electrically insulating coating (6). The method of claim 1, A _PF The sealing segment (1), characterized in that the ratio of _PS to A lies in the range of 0.004 to 0.10. The method of claim 1, wherein the segment projection outline (2 _P) opening projecting contour in the (4 _P) is an opening projecting contour (4 _P) of 2/6, A _PS so completely placed inside the polygon (P ₂₎ A sealing segment (1), characterized in that equilateral and conformal polygons (P ₂ ) having an area of 1 are laid so as to be aligned inside the segment projection contour (2 _P ). The first segment according to claim 1, wherein within the segment projection contour (2 _P ) the aperture projection contour (4 _P ) is a first segment at two or more points where a straight line intersects the aperture projection contour (4 _P ) at one or more points. The sealing segment (1), characterized in that it lies so as not to intersect the projection contour (2 _P ). In the sealed segment battery cell unit 31 comprising a battery cell 40,
Sealed segment battery cell unit (31), characterized in that the battery cell (40) is in thermal contact with the main face (11) of the sealing segment (1) according to any one of the preceding claims. 12. The method of claim 11, wherein the thermal contact is formed by physical contact of the battery cell (40) with one of the major faces (11) of the sealing segment (1), wherein the battery cell (40) is a through opening (3) Sealed segment battery cell unit 31, characterized in that it does not overlap with. 12. The method of claim 11, wherein a frame (50) abutting the main surface (11) is provided, which is limited by the battery cell (40), the sealing segment (1) and the frame (50), and the fluid is A sealed segment battery cell unit (31), characterized in that it is in thermal contact with the battery cell (40) so that a channel (K) that can be introduced into it through the through opening (3) is formed. 14. A channel (K) according to claim 13, provided with a second sealing segment (101) according to any one of claims 1 to 11, in which case through the through opening (3) of one sealing segment (1) The main surface 112 of the second sealing segment 101 is frame 50 so that fluid that can flow into it can be discharged to the outside of the channel K through the through opening 103 of the second sealing segment 101. A sealed segment battery cell unit (31), characterized in that it contacts ). 15. The method according to claim 14, characterized in that the two through openings (3, 103) are arranged such that these through openings are connected via two sections (K _A1 , K _A2 ) of equal length of the channel (K). Sealed segment battery cell unit (31).

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