Cell holder for holding battery cells and cell modules

Description

Technical field

[0001] The present invention relates to a cell holder for holding at least one cylindrical battery cell, preferably for use in a traction battery for electric or hybrid vehicles or vehicles with fuel cells, and to a method for producing a cell holder. State of the art

[0002] Battery systems for electric and hybrid vehicles, as well as fuel cell vehicles, are the subject of current research and development. Typically, several cylindrical battery cells are combined into a battery module, also known as a "battery pack." A traction battery for a vehicle, in turn, comprises one or more battery modules.

[0003] A battery module has cell holders whose function is to mechanically secure the battery cells and thus combine them into a larger unit, the battery module. The cell holders can be constructed from one or more molded parts, or they can be completely or partially manufactured from potting compound after the initial placement of the battery cells to permanently secure them in the battery housing.

[0004] A known design uses honeycomb-shaped cell holders, as described, for example, in US 2010 / 0136413 A1. In this case, the battery cells are arranged parallel to each other, upright, and staggered in rows, forming a structure of the closest circular packing, as seen in cross-section relative to the longitudinal extent of the battery cells. The battery cells are held axially on both sides by a cell holder each, which has cup-shaped recesses corresponding to the battery cells, into which the battery cells are inserted.

[0005] The Figure 1shows a cross-sectional view of a section of an exemplary cell holder 1 with cup-shaped holding sections 10, which are formed by a base 11 and side walls 12. The holding sections 10 are designed such that they receive an axial end of each battery cell 2 and fix it in the directions parallel to the base 11 and directed towards the base 11. The battery cell 2 stands upright in the installed state, ie its axial direction or cell axis A is perpendicular to the base 11. By using two such cell holders 1, each of which fixes one end of the battery cells 2, the battery cells 2 are held in a sandwich-like manner and thus form a cell module or battery module.

[0006] It is known to manufacture the cell holders 1 as injection-molded plastic parts. However, such injection-molded cell holders have so-called draft angles or draft slopes to allow for easy demolding from their mold. For illustration, the draft angles α, which are manifested by a tapering of the side walls 12 starting from the base 11 in the axial direction, are shown in the Figure 1 exaggerated. After the plastic has hardened, the cell holder 1 is removed from the mold (not shown in the figures) along a demolding direction E that runs parallel to the cell axis A.

[0007] Such manufacturing-related demolding angles prevent a defined and flat contact between the side walls and the battery cells. The battery cells are generally only supported by the side walls along a linear contour, see contact areas K in the Figure 1, but not across the entire surface, which makes precise positioning and alignment, as well as secure holding of the battery cells, more difficult. This also has a negative impact on assembly, which may require a considerable amount of clearance. The interface between the battery cells and the cell holder is also sensitive to manufacturing tolerances of the cell holder and the battery cells. A holding section whose side walls completely surround the corresponding battery cell generally results in increased installation space, but particularly due to the thickening on the bottom side due to the demolding angle.

[0008] When arranging battery cells, it is important to ensure that sufficient spacing is maintained between adjacent battery cells to prevent thermal propagation to neighboring cells in the event of a so-called "thermal runaway" of a battery cell and to rule out a short circuit. For this purpose, it is common practice to design cell holders to ensure sufficient spacing between the battery cells. The battery cells form a cell pattern, for example, square or hexagonal, in which neighboring cells are all equidistant from one another.

[0009] However, the probability of a short circuit between neighboring battery cells depends not only on the distance but also on their interconnection. For example, a greater distance must be maintained between neighboring battery cells connected electrically in series than between neighboring battery cells connected electrically in parallel. However, today's cell holders generally have identical cell spacing, which, for safety reasons, must then meet the spacing requirements for two battery cells connected in series. If the electrical interconnection within a battery module is known and cannot be changed, this results in a suboptimal packing density of the battery cells and thus a suboptimal energy density.If the cell holder is intended to allow for various electrical connection patterns, the number of technically feasible configurations is still limited, so even in these cases, most cell spacings are kept unnecessarily large. In addition to the loss of energy density, larger cell spacings also result in increased material usage in the cell holder and increased weight. Description of the invention

[0010] An object of the invention is to provide an improved cell holder for holding at least one cylindrical battery cell and an improved cell module.

[0011] The object is achieved by a cell holder having the features of claim 1, a cell holder having the features of claim 8 and a cell module having the features of claim 13. Advantageous further developments follow from the subclaims, the following presentation of the invention and the description of preferred embodiments.

[0012] The cell holder described herein is preferably intended for use in a traction battery for electric or hybrid vehicles or vehicles with fuel cells. A cell module or battery module, typically comprising multiple battery cells, may have one or two cell holders to combine and hold or fix the battery cells.

[0013] The cell holder according to the invention comprises a plurality of holding sections, each having a base and side walls and thus forming a (preferably concave) section which is designed to receive and fix an axial end of a battery cell, i.e. a base area and at least partially the outer surface of the battery cell. Due to the cylindrical shape of the battery cell, it defines a cell axis and an outer surface which extends along the cell axis and in the circumferential direction of the battery cell. The battery cell is fixed by the cell holder in at least one direction, but preferably in several directions. The base and the side walls are therefore preferably designed to fix the corresponding battery cell in all directions parallel to the base and in the direction towards the base.

[0014] From DE 10 2013 207 536 A1 a cell block with a cell fixation for a battery is known, wherein a collar is provided for each opening in the cell fixation in order to fix the respective battery cell.

[0015] The side walls of the respective holding sections comprise at least one contact surface arranged substantially perpendicular to the base in a contact area with the battery cell and configured to be in planar or linear contact with a portion of a lateral surface of the battery cell when the battery cell is inserted, and at least one deformable contact section configured to deform upon insertion of the battery cell into the corresponding holding section. The contact surface preferably does not deform in this case.

[0016] In other words, the concavely curved contact surface aligns with a corresponding section of the battery cell's lateral surface, resulting in flat contact. The deformable contact section is located elsewhere, preferably opposite the contact surface. The contact section is preferably elastically deformable, so that it acts like a spring.

[0017] The contact surface preferably has a cylindrical or partially cylindrical shape. It should be noted that the terms "cylindrical" and "circular" do not necessarily define a complete cylinder circumference or circle, but rather encompass the contour of a corresponding segment, since the contact surface does not completely surround the battery cell, but rather only lies flat against a portion of the battery cell circumference, for example, in the range of 20° to 90°.

[0018] The cell holder constructed in this way can be manufactured in a resource- and cost-efficient manner, as the geometries of the holding sections with the corresponding side walls can be easily manufactured, for example by injection molding. The holding sections enable precise positioning and alignment as well as a defined mechanical connection of the battery cell(s) to the cell holder. Cell assembly is facilitated by the deformable contact section. The holding sections also allow for a particularly space-saving arrangement of the battery cells directly next to one another, as the outer surface of an inserted battery cell can remain free between the contact areas and does not have to be completely covered with cell holder material. The achieved effects are also comparatively insensitive to manufacturing tolerances of the cell holder and the battery cells.Due to its insensitivity to fluctuating cell diameters, the cell holder is able to hold battery cells from different manufacturers without modification, thus saving resources and costs when changing battery cell types / manufacturers.

[0019] Preferably, the contact surface is connected to the base, thereby making that area of ​​the corresponding holding section, which largely defines the position and orientation of the battery cell, particularly stable. The base and the contact surface are preferably formed as a single piece.

[0020] Preferably, the deformable contact section is not connected to the ground, whereby the deformability can be realized in a structurally simple manner.

[0021] Preferably, the contact surface is concave, in particular circular, in a cross-section parallel to the ground, whereby it interacts optimally with a correspondingly shaped circular-cylindrical battery cell.

[0022] According to the invention, the contact surface and the deformable contact section form a non-zero angle without an inserted battery cell, as seen in a cross-section perpendicular to the ground. This allows tolerances to be compensated and the fixation of the battery cell to be improved. Furthermore, the deformable contact section functions as an insertion chamfer for a corresponding battery cell.

[0023] Preferably, the holding sections each comprise a plurality of, in particular exactly two, deformable contact sections, thereby improving the fixation and correct alignment of the corresponding battery cell and stabilizing the holder. The features, technical effects, and advantages described with regard to the use of a deformable contact section apply analogously to any further deformable contact sections.

[0024] Preferably, the side wall of a holding section supporting the contact surface has a deformable contact section of an adjacent holding section. In other words, the contact surface and the one or more deformable contact sections of an adjacent holding section are preferably formed integrally and by precisely one structural part. In this way, adjacent holding sections are structurally integrated with one another, allowing the cell holder to be designed particularly compactly.

[0025] The cell holder is preferably made of plastic, in particular by an injection molding process. The cell holder is preferably formed in one piece. The cell holder according to one of the embodiments described above is particularly suitable as an injection-molded part because its structural properties and the manufacturing process interact synergistically, as will become clear from the description of the process.

[0026] The above-mentioned object is further achieved by a cell holder for holding cylindrical battery cells, preferably for use in a traction battery for electric or hybrid vehicles or vehicles with fuel cells, wherein the cell holder has: a plurality of holding sections, each having a base and side walls and thus each forming a section which is configured to receive and fix a base area and, at least in sections, a lateral surface of a respective battery cell; wherein the holding sections are configured such that battery cells inserted therein have at least partially different distances from their nearest neighbors.

[0027] The cell holder may have one or more of the features defined above. The described technical effects, advantages, and embodiments then apply analogously to the cell holder defined above.

[0028] When determining the distance, the shortest distance between the lateral surfaces of the corresponding, adjacent battery cells in a sectional plane perpendicular to the cell axes is used. Furthermore, it should be noted that the holding sections clearly define the position and orientation of the battery cells, so that the battery cells in their inserted state, in particular their distances defined above, imply a structural definition of the holding sections. To determine the distance between adjacent battery cells, a fully populated cell holder is assumed, thus eliminating differences in distance due to unoccupied holding sections.

[0029] By designing the cell holder so that its holding sections allow for varying spacing between the inserted battery cells, the packing density of the battery cells can be optimized compared to equidistant cell placement without compromising safety. This results in less material usage, lower costs, and a lower weight of the cell holder.

[0030] Preferably, several, for example three, holding sections are combined to form a cell group, thereby combining the advantage of a high packing density with maintaining flexibility with regard to the electrical interconnection.

[0031] Preferably, adjacent cell groups are separated from one another by a group wall, thereby increasing electrical insulation and / or mechanical safety. The cell groups are thus preferably separated from one another by stabilizing webs or group walls. There are no such group walls within the cell groups. Depending on the application, the material of the cell holder, stability requirements, and the like, more or fewer holding sections can be combined to form a cell group. Such a combination, in turn, results in material and space savings, whereby the cell modules constructed from the battery cells and one or two of the cell holders shown here can be designed to be particularly compact.

[0032] Preferably, the holding sections are arranged such that the distance between adjacent battery cells within a cell group is smaller than the distance between adjacent battery cells of adjacent cell groups.

[0033] From a purely electrical perspective, in extreme cases, a cell module can comprise an entire battery group (=logical cell, a group of battery cells connected in parallel) to achieve maximum packing density. For mechanical reasons, however, such a battery group is preferably divided into several cell groups with corresponding cell walls, which also allows flexibility with regard to possible electrical connections without having to change the structure or design of the cell holder. Compared to a conventional design, this still achieves a higher packing density with less material usage, while maintaining flexibility with regard to electrical connections and safety.

[0034] Preferably, the holding sections are arranged in rows, with the holding sections of adjacent rows particularly preferably being arranged offset, approximately offset by half the size of a holding section. In this way, a honeycomb structure or a structure of closest circular packing can be produced, viewed in a cross-section parallel to the ground. In this way, the number of battery cells accommodated per unit area can be maximized.

[0035] For the same reason, one or more of the holding sections are preferably designed such that their side walls do not completely enclose the outer surface of a corresponding inserted battery cell with material. The grouping of the holding sections described above can thereby be created or at least supported.

[0036] Preferably, the holding sections of each cell group are located in a row, i.e. in this case the cell groups do not span several rows, thus achieving a good compromise between flexibility of the electrical circuitry and mechanical stability.

[0037] The above-mentioned object is further achieved by a cell module, preferably for use in a traction battery for electric or hybrid vehicles or vehicles with fuel cells, wherein the cell module comprises: at least one cell holder according to one of the embodiments described above; a plurality of battery cells, each of which is inserted into a holding section of the cell holder and thereby fixed; and a wiring section that electrically connects the battery cells to one another. Preferably, the cell module comprises two cell holders that hold the battery cells in a sandwich-like manner.

[0038] The features, technical effects, advantages and embodiments described with regard to the cell holders apply analogously to the cell module equipped therewith.

[0039] Preferably, the interconnection section is configured such that battery cells within a cell group are interconnected in parallel, while battery cells of different cell groups are interconnected in series, thereby ensuring electrical and mechanical safety despite high packing density.

[0040] Battery cells connected in parallel each define a battery group in the cell module. The battery groups present in the cell module are preferably the same size, i.e., they comprise the same number of battery cells. Preferably, the number of battery cells in a battery group is divisible by the number of holding sections per cell group, thereby combining the advantage of a high packing density with maintaining flexibility in terms of electrical interconnection.

[0041] According to a specific embodiment, the cell module comprises a total of 297 cell positions, arranged in 11 rows and 27 columns, with three battery cells grouped in rows to form a cell group. This design allows for a variety of circuit configurations. For example, the battery cells can be connected in parallel in rows, and the rows can be connected in series. This circuit configuration is referred to as the "basic circuit" and abbreviated as "11s27p," where "s" stands for serial and "p" for parallel in the sp nomenclature. The basic circuit configuration is a preferred configuration with regard to busbar geometry and even current distribution. However, the grouping of the battery cells allows for further circuit patterns and configurations, taking into account the safety aspect of avoiding serial connection of battery cells with close spacing.

[0042] A cell module preferably comprises a plurality of cylindrical battery cells and two cell holders in order to hold the battery cells on both sides in the direction of the cell axis by means of a cell holder each.

[0043] The above-mentioned object is further achieved by a method for producing a cell holder, preferably for use in a traction battery for electric or hybrid vehicles or vehicles with fuel cells, wherein the cell holder is configured to hold at least one cylindrical battery cell that defines a cell axis. According to the method, the cell holder is injection-molded from a plastic using a mold that preferably has two mold halves. If multiple tool parts / tool ​​halves are used, these can be moved, pivoted, or moved relative to one another in some other way to open the tool. In any case, the cell holder can be removed from the mold after the plastic in the mold has sufficiently cured.

[0044] According to the invention, the cell holder is removed from the mold along a demolding direction, wherein the demolding direction and the cell axis do not run parallel.

[0045] By ensuring that the demoulding direction and the cell axis are not parallel, the contact between the battery cell and the cell holder can be improved, since the demoulding angles required or customary for injection moulding do not result in any loss of quality, but can be used directly to stabilise the battery cell(s).

[0046] This technical effect is achieved in particular with a cell holder according to the above description. The features, technical effects, advantages, and embodiments described with reference to the cell holder apply analogously to the method.

[0047] Further advantages and features of the present invention will become apparent from the following description of preferred embodiments. The features described therein can be implemented alone or in combination with one or more of the features presented above, provided the features do not contradict each other. The following description of preferred embodiments is provided with reference to the accompanying drawings. Short description of the characters

[0048] Preferred further embodiments of the invention are explained in more detail by the following description of the figures. In the figures: Figure 1 shows a section of a conventional cell holder, shown in a cross-section parallel to the cell axis, with exaggerated demolding angles and a demolding direction parallel to the cell axes; Figure 2 shows a plan view of a cell holder with a plurality of holding sections, arranged in rows offset from one another; Figure 3 shows a section of a cell holder, shown in a cross-section parallel to the cell axis, whose demolding direction does not run parallel to the cell axis; Figure 4 shows a perspective section of a cell holder, showing a free holding section and a holding section equipped with a battery cell; Figure 5 shows a perspective section of a holding section of a cell holder, viewed obliquely into the holding section; Figure 6 shows a view from below of a holding section of a cell holder with an inserted battery cell.Figure 7 shows a perspective section of a cell holder according to a further embodiment; Figure 8 shows a perspective section of the cell holder, viewed from a different perspective; Figure 9 shows a top view of the cell holder; Figure 10 shows a schematic, qualitative representation of a grouping of battery cells with different spacings; Figure 11 shows a perspective, exploded view of a cell module in a basic circuit; and Figures 12a, 12b and 12c show schematic representations of alternative circuits. Detailed description of preferred embodiments

[0049] Preferred embodiments are described below with reference to the figures. Identical, similar, or equivalent elements are provided with identical reference numerals in the figures, and a repeated description of these elements is partially omitted to avoid redundancy.

[0050] The Figure 2is a plan view of a cell holder 1 with a plurality of holding sections 10 which are used to hold cylindrical battery cells 2, cf. Figures 3, 4 and 6 , are arranged. The cell holder 1 is preferably made of a plastic, in particular by injection molding. Furthermore, the cell holder 1 is preferably formed in one piece or essentially in one piece.

[0051] The holding sections 10 form concave sections, ie they are cup-shaped or designed as depressions, so that one of the two axial ends of a battery cell 2 can be inserted into such a holding section 10, as can be seen particularly clearly from the Figures 3 and 4 emerges.

[0052] In the present embodiment, the holding sections 10 are arranged in rows R, with adjacent rows R being offset by the dimension of half a holding section 10, resulting in a honeycomb structure or a structure of closest circular packing. In this way, the number of battery cells 2 accommodated per unit area can be maximized. However, the holding sections 10 can also be arranged in other ways, for example, without offsetting adjacent rows R.

[0053] The holding sections 10 comprise a base 11 which, when the battery cell 2 is inserted, is in contact with at least part of the corresponding base surface 2a of the battery cell 2 and in this way holds the battery cell 2 axially, ie along the cell axis A (cf. Figure 3). It should be noted that the base surfaces 2a of the battery cells 2 do not have to form perfect planes, but may have curvatures, deformations and the like in the axial direction A of the battery cell 2, as shown, for example, in the Figure 6 is indicated.

[0054] The base 11 preferably has a base opening 11a, which can be a generous recess to enable or facilitate electrical contacting of the battery cells 2.

[0055] The holding sections 10 further comprise side walls 12, which are designed to fix the battery cells 2 in the inserted state in the lateral direction, ie perpendicular to the cell axis A. The side walls 12 have a special structure that improves the hold of the battery cells 2. Such an improvement of the interface between the holding section 10 and the battery cell 2 can be achieved by utilizing production-related demolding angles α, cf. Figure 3, take place.

[0056] With reference to the Figure 3 The direction in which the cell holder 1, if manufactured as an injection-molded part, is removed from the corresponding mold (not shown in the figures), is referred to as the demolding direction E. According to the present exemplary embodiment, the demolding direction E and the cell axis A form an angle β that is different from zero, which angle β corresponds to the demolding angle α in the case of vertically positioned battery cells 2. In other words, the demolding direction E and the cell axis A do not run parallel. By the demolding direction E and the cell axis A not running parallel, the contact between the battery cell 2 and the side walls 12 of the corresponding holding section 10 can be improved, as explained in more detail below.

[0057] According to the present exemplary embodiment, the side walls 12 of a holding section 10 comprise a contact surface 12a, which is substantially perpendicular to the base 11, can be connected to the base 11, and is concavely, in particular cylindrically, curved perpendicular thereto in such a way that it coincides with a corresponding section of the lateral surface 2b of the battery cell 2, thus being in planar contact with the battery cell 2. Preferably, the cylindrical contact surface 12a is circularly curved perpendicular to the cell axis A in order to optimally interact with circular-cylindrical battery cells 2.

[0058] The terms "cylindrical" and "circular" do not necessarily define a complete cylinder circumference or circle. Rather, they encompass the contour of a corresponding partial section, i.e., a segment, since the cylindrical contact surface does not completely surround the battery cell, but only lies flat against a portion of the battery cell circumference, for example, in the range of 20° to 90°.

[0059] The side walls 12 further comprise one or more, preferably exactly two, deformable contact sections 12b for each holding section 10. The deformable contact sections 12b are at least partially deformed when the battery cell 2 is inserted, in contrast to the contact surface 12a, as can be seen particularly clearly from the Figure 3The contact sections 12b are preferably elastic, thus spring-like, and for this purpose are preferably not or not completely connected to the base 11. The deformable contact sections 12b can make planar contact or linear contact in the axial direction with the lateral surface 2b of the battery cell 2.

[0060] In the unpopulated state, ie without the battery cell 2 inserted, the contact surface 12a and a corresponding contact section 12b preferably form an angle 2α different from zero, cf. Figure 3, where α denotes the above-mentioned demolding angle. The demolding angle α defines a taper of the holding section 10 starting from the base 11 in the demolding direction E, which, on the one hand, simplifies the removal of the cell holder 1 from a corresponding injection molding tool and, on the other hand, ensures reliable clamping of a battery cell 2 to be inserted due to the deformability of the contact sections 12b. At the same time, the vertical contact surface 12a ensures precise positioning and alignment of the battery cell 2.

[0061] In the present exemplary embodiment, the side walls 12 comprise a vertical contact surface 12a and two opposing contact sections 12b for each holding section 10. This results in three contact points per battery cell 2, with at least the contact surface 12a establishing a flat contact. The contact sections 12b preferably extend obliquely relative to the cell axis A, so that they function as insertion chamfers for a corresponding battery cell 2. The contact sections 12b are deformed during cell assembly. They can be manufactured by injection molding with conventional draft angles and from only two tool halves.

[0062] The contact surfaces 12a and deformable contact sections 12b can be structurally integrated with each other, as is particularly clear from the Figures 4 and 5The side wall 12 of a holding section 10 carrying the contact surface 12a can simultaneously form a contact section 12b of an adjacent holding section 10. For example, the contact section 12b of the holding section 10 of a particular row R is located at the height of the apex of the contact surface 12a of an adjacent holding section of the row R-1, see also Figure 3 .

[0063] The Figures 7 to 9 show a further embodiment which differs from the previous embodiments in the structure of the contact surface 12a. While the contact surface 12a according to the embodiment of the Figures 2 , 4 and 5is cylindrically bent (seen in a cross section parallel to the base 11) in order to enter into a planar contact with the lateral surface 2b of the battery cell 2, the contact surface 12a and the lateral surface 2b of the battery cell 2 according to the present embodiment essentially form a line contact at two points, as is particularly clear from the Figure 9 The contact surface 12a therefore does not have to correspond to the curvature of the battery cell 2, but can, for example, be straight or polygonal, viewed in a cross-section perpendicular to the base 11. In this way, the cell holder 1 can be used particularly flexibly for battery cells 2 of different shapes and / or dimensions.

[0064] The subdivision of the side walls 12 into a contact surface 12a and one or more deformable contact sections 12b has the consequence that the lateral surface 2b of an inserted battery cell 2 can remain free between these contact areas and does not have to be completely enclosed by material of the cell holder 1 over 360°.

[0065] This allows cell groups 1a to be created from battery cells 2 that are located directly next to each other. Figure 2Cell groups 1a, each consisting of three holding sections 10, are shown as examples. The cell groups 1a are separated from one another by stabilizing webs or group walls 1b in the direction of the rows R. Depending on the application, the material of the cell holder 1, the stability requirements, and the like, more or fewer holding sections 10 can be combined to form a cell group 1a. Such a combination, in turn, results in material and space savings, whereby the cell modules 100 (cf. Figure 11 ) can be made particularly compact.

[0066] The battery cells 2 of a cell group 1a are preferably electrically connected in parallel, since the outer surfaces 2b of the battery cells 2 carry the same electrical potential and are likely to touch each other.

[0067] The cell holder 1 can be manufactured in a resource- and cost-efficient manner, as the geometries of the holding sections with the corresponding side walls 12 can be easily injection-molded, for example, using appropriate mold halves. The holding sections 10 enable precise positioning and a defined mechanical connection of the battery cells 2 to the cell holder 1. Cell assembly is facilitated by insertion bevels formed by the deformable contact sections 12b. The cell holder 1 allows for maintaining a constant component wall thickness, which has a beneficial effect on manufacturability and the fire protection class to be achieved. The holding sections 10 allow for a space-saving arrangement of the battery cells 2 directly next to one another. The achieved effects are also comparatively insensitive to manufacturing tolerances of the cell holder 1 and the battery cells 2.Due to its insensitivity to fluctuating cell diameters, the cell holder 1 is able to hold battery cells 2 from different manufacturers without modification, thus saving resources and costs in the event of a change of battery cell types / manufacturers.

[0068] Returning to the discussion with reference to the Figure 2 described grouping of battery cells 2, the grouping can be realized by different distances between neighboring battery cells 2 within a cell group 1a and neighboring battery cells 2 of neighboring cell groups 1a. This is shown in the Figure 10schematically shown, where a1 denotes the intra-group cell spacing, ie the distance between adjacent battery cells 2 within a cell group 1a, and a2 denotes the group-wise cell spacing, ie the distance between adjacent battery cells 2 of adjacent cell groups 1a. In this case, the shortest distance between the lateral surfaces 2b of the corresponding battery cells 2 is used.

[0069] The grouping of three according to the Figures 2 and 10 is only an example, and more or fewer battery cells 2 can be combined to form a cell group 1a. If the grouping is realized by different distances a1, a2, the cell holder 1 does not necessarily have to have webs or group walls 1b in the sections with larger distances a2, although this is possible according to the Figure 2 is a preferred embodiment.

[0070] Particularly preferably, units of battery cells 2 with a small spacing a1, i.e., battery cells 2 within a cell group 1a, are connected in parallel, while battery cells 2 of different cell groups 1a are connected in series in this case. In this way, a higher packing density is achieved compared to equidistant cell placement without compromising safety.

[0071] The Figure 11 shows a cell module 100 with two cell holders 1 and battery cells 2 held sandwiched between them. Furthermore, a housing section 3, cooling section 4 and a wiring section 5 are shown.

[0072] In the embodiment of the Figure 11The cell module 100 comprises a total of 297 cell positions, oriented in 11 rows R and 27 columns, with three battery cells 2 being grouped in rows to form a cell group 1a. Furthermore, the battery cells 2 are connected in parallel rows and the rows R are connected in series. This connection is referred to as the "basic connection" and abbreviated as "11s27p", where in the sp nomenclature "s" stands for serial and "p" for parallel. The basic connection is defined with respect to busbar geometry by the connection section 5 of the Figure 11 shown, and uniform current distribution is a preferred configuration.

[0073] However, the grouping of the battery cells 2 allows for further wiring patterns or configurations, taking into account the safety aspect that a serial connection of battery cells 2 with a small distance a1 is to be avoided. Figures 12a to 12cshow exemplary configurations that can be reasonably represented in terms of busbar geometry and current distribution. Fields of the same gray level indicate parallel-connected battery cells 2, while fields of different gray levels form serially connected units. The number in parentheses after the sp nomenclature indicates the number of positions in the cell module 100 actually occupied by battery cells 2. Fields marked with "u" ( Figures 12b and 12c ) are unoccupied. The configurations according to the Figures 11 , 12a , 12b , 12c are not complete, other variants are also conceivable.

[0074] In addition, the number and configuration of useful interconnection patterns vary depending on the number of battery cells 2 combined into cell groups 1a. From a purely electrical perspective, in extreme cases, to achieve maximum packing density, a cell module 100 can comprise an entire battery group (=logical cell, group of battery cells 2 connected in parallel). For mechanical reasons, however, such a battery group is usually divided into several cell groups 1a, which also allows flexibility with regard to possible electrical interconnections without having to change the structure or design of the cell holder 1. Compared to a conventional design, a higher packing density is still achieved with less material usage, while maintaining flexibility with regard to electrical interconnection and safety.

[0075] Preferably, the conduction section 5 is arranged such that potential differences between adjacent battery cells, ie serial connections, always occur only along separating walls, in particular group walls 1b.

[0076] The use of different distances a1, a2 between battery cells 2, in particular the grouping of battery cells 2 using group walls 1b, enables optimization of the packing density compared to equidistant cell placement without compromising safety. This results in lower material usage, lower costs, and a lower weight of the cell holder 1. If the number of holding sections 10 per cell group 1a is a divisor of the number of battery cells 2 in a battery group, i.e., a group of battery cells 2 connected in parallel, the advantage of a high packing density is combined with the retention of flexibility with regard to the electrical interconnection.

[0077] Where applicable, all individual features shown in the embodiments may be combined and / or exchanged with one another without departing from the scope of the invention. List of reference symbols

[0078] 1Cell holder 1aCell group 1bGroup wall 2Battery cell 2aBase area 2bShell area 3Housing section 4Cooling section 5Connection section 10Holding section 11Bottom 11aBottom opening 12Side wall 12aContact area 12bDeformable contact section 100Cell module AZell axis / axial direction EEmpolding direction KContact area RRow αDraft angle βAngle a1Intergroup cell spacing a2Group-wise cell spacing

Claims

1. Cell holder (1) for holding cylindrical battery cells (2), preferably for use in a traction battery for electric or hybrid vehicles or vehicles with fuel cells, wherein the cell holder (1) has: multiple holding portions (10) which in each case have a bottom (11) and side walls (12) and thus in each case form a portion which is configured to receive and to fix a base (2a) and, at least sectionally, a lateral surface (2b) of a respective battery cell (2); wherein the side walls (12) of the respective holding portions (10) comprise: at least one contact surface (12a) which is arranged in a region of contact with the battery cell (2) substantially perpendicularly to the bottom (11) and is configured such that, with a battery cell (2) inserted, it is in areal or linear contact with a portion of a lateral surface (2b) of the battery cell (2), and at least one deformable contact portion (12b) which is configured to deform when the battery cell (2) is plugged into the corresponding holding portion (10), characterized in that, without a battery cell (2) inserted, the contact surface (12a) and the deformable contact portion (12b) form a non-zero angle.

2. Cell holder (1) according to Claim 1, characterized in that the contact surface (12a) is attached to the bottom (11) and / or the deformable contact portion (12b) is not or not completely attached to the bottom (11) and / or the contact surface (12a) is concavely curved in a cross section parallel to the bottom (11).

3. Cell holder (1) according to Claim 1 or 2, characterized in that the contact surface (12a) has a cylindrical or partially cylindrical shape, wherein the cylindrical contact surface (12a) is preferably circularly curved in a cross section parallel to the bottom (11).

4. Cell holder (1) according to one of the preceding claims, characterized in that the holding portions (10) in each case comprise exactly two deformable contact portions (12b).

5. Cell holder (1) according to one of the preceding claims, characterized in that the side wall (12) of a holding portion (10) bearing the contact surface (12a) has a deformable contact portion (12b) of a neighbouring holding portion (10).

6. Cell holder (1) according to one of the preceding claims, characterized in that one or more of the holding portions (10) are formed in such a way that the side walls (12) thereof do not completely surround the lateral surface (2b) of a corresponding inserted battery cell (2) with material.

7. Cell holder (1) according to one of the preceding claims, characterized in that the holding portions (10) are configured in such a way that at least some battery cells (2) inserted therein are at different distances (a1, a2) from their nearest neighbours.

8. Cell holder (1) according to one of the preceding claims, characterized in that multiple, preferably three, holding portions (10) are combined to form a respective cell group (1a), wherein neighbouring cell groups (1a) are preferably separated from one another by means of a group wall (1b).

9. Cell holder (1) according to Claim 8, characterized in that the holding portions (10) are configured in such a way that the distance (a1) between neighbouring battery cells (2) within a cell group (1a) is smaller than the distance (a2) between neighbouring battery cells (2) of neighbouring cell groups (1a).

10. Cell holder (1) according to one of the preceding claims, characterized in that the holding portions (10) are arranged in rows (R), wherein the holding portions (10) of neighbouring rows (R) are arranged in an offset manner, preferably in a manner offset by the dimension of half a holding portion (10).

11. Cell holder (1) according to Claim 8 or 9 and Claim 10, characterized in that the holding portions (10) of a respective cell group (1a) are situated in a row (R).

12. Cell module (100), preferably for use in a traction battery for electric or hybrid vehicles or vehicles with fuel cells, wherein the cell module (100) has: at least one cell holder (1) according to one of the preceding claims; multiple battery cells (2) which are in each case inserted into a holding portion (10) of the cell holder (1) and thus fixed; and an interconnection portion (5) which electrically connects the battery cells (2) to one another.

13. Cell module (100) according to Claim 12 and Claim 8, characterized in that the interconnection portion (5) is configured in such a way that battery cells (2) within a cell group (1a) are interconnected in parallel while battery cells (2) of different cell groups (1a) are interconnected in series.

14. Cell module (100) according to Claim 13, characterized in that battery cells (2) in the cell module (100) that are interconnected in parallel in each case define a battery group and the number of battery cells (2) in a battery group is divisible by the number of holding portions (10) per cell group (1a).