Mounting device for the adjacent arrangement of planar electrochemical energy storage cells, accumulator block and manufacturing method therefor

Abstract

Mounting device for the adjacent arrangement of planar electrochemical energy storage cells (Z) along an extension direction (E), comprising: a plurality of buffer elements (10) made of plastic, which have a thermal conductivity of more than 0.5 W / mK and a specific electrical resistance of more than 10 10 Ωm, wherein each buffer element (10) has positioning and connecting means in a first edge region (11) and the positioning and connecting means are designed such that that they hold the buffer elements (10) at a periodic distance (D) from one another, wherein the positioning and connecting means in the first edge region (11) of the buffer elements (10) are formed as a one-piece base connecting element (15) extending along the extension direction (E) between the buffer elements (10), characterized in that the base connecting element (15) is formed from a material such that it can be elastically deformed between two adjacent buffer elements (10) to such an extent from the direction of extension (E) that edge regions of adjacent buffer elements (10) spaced apart from the base connecting element (15) assume an extended bending distance (B) which is at least 1.5 times the value of the periodic distance (D) compared to a parallel alignment of adjacent buffer elements (10) with the periodic distance (D).

Description

[0001] The invention relates to a holding device for the adjacent arrangement of planar electrochemical energy storage cells and a manufacturing method for an accumulator block with such a holding device.

[0002] Double-layer capacitors or electrochemical energy storage cells coupled to battery blocks in the form of lead batteries, nickel-metal hydride, lithium-ion, or lithium-polymer batteries can be used as energy suppliers and storage devices for electric vehicle applications (hybrid vehicles and pure electric vehicles).

[0003] The most important requirements when assembling the individual electrochemical energy storage cells into a battery block are that the energy storage cells within the modular assembly of the battery block have sufficient mechanical fixation, good thermal coupling to the provided cooling devices, and sufficient electrical insulation between the energy storage cells. In addition, mechanical tolerance compensation of the energy storage cells due to temperature fluctuations and aging, as well as vibration damping, must be ensured.

[0004] Typically, the individual energy storage cells have a flat shape. In the context of the present invention, the feature of a flat electrochemical energy storage cell is understood to mean an energy storage cell that has an average thickness that is at most one-fifth to one-eighth of the height or width of the energy storage cell. Preferably, the thickness is only one-tenth to one-twentieth of the width or height. Such flat energy storage cells are typically arranged with their large-area sides facing one another, viewed in the direction of their thickness, and in this way are mechanically and electrically coupled to form accumulator blocks. The large-area side is also referred to below as the coupling surface. The coupling surface is preferably flat and can have any two-dimensional geometry.Preferably, this is rectangular or square, because the coupling of such energy storage cells described above results in cuboid-shaped accumulator blocks.

[0005] The electrochemical energy storage cells are usually coupled to accumulator blocks via a holding device consisting of a plurality of plastic buffer elements.

[0006] DE 198 49 491 C1 describes an electrochemical energy storage device. The electrochemical energy storage device comprises a plurality of storage cells arranged adjacent to one another in at least one row. A heat exchanger structure for temperature control is associated with the storage cells. A temperature control medium can flow through the storage cells and the storage cells have at least one flow channel and at least one corresponding return channel, which are connected to one another via at least one closed heat exchanger channel.

[0007] DE 102011 002 415 A1 describes a temperature control system for galvanic cells using heat-conducting plastic compounds. For this purpose, a temperature control plate or a plastic housing for galvanic cells comprises at least one section intended for heat dissipation, which is formed from a plastic compound containing at least one additive to increase thermal conductivity.

[0008] From DE 602 13 474 T2 a device and a method for temperature control in electrochemical cells with a high energy density are known.

[0009] EP 2 200 109 A2 discloses a holding and cooling device for at least one energy storage unit, wherein the holding and cooling device comprises a cooling base plate with a plurality of holding elements fastened thereto in a materially bonded manner, wherein a receiving pocket for an energy storage unit is formed by at least two holding elements.

[0010] DE 10 2011 011 375 A1 describes a cooling assembly for a battery assembly having at least one conduit and at least one cooling plate, wherein the conduit has a flexible portion to support relative movement between an inlet end and an outlet end thereof to selectively expand and contract the cooling assembly, and wherein the cooling plate has a flow channel formed therein, wherein at least one battery cell is arranged adjacent to and in heat transfer communication with the at least one cooling plate to transfer heat from the at least one battery cell to a fluid arranged in the flow channel.

[0011] DE 10 2012 112 392 A1 discloses a high-voltage battery with a cooling device comprising a plurality of cooling elements spaced apart from one another, each of which has a receiving space for a battery cell device. To simplify and / or improve the cooling of the high-voltage battery, the cooling elements are combined in a one-piece heat sink.

[0012] The present invention is based on the object of providing a holding device and a manufacturing method of an accumulator block with such a holding device, wherein the holding device significantly simplifies the coupling of individual electrochemical energy storage cells to an accumulator block and thus makes it more cost-effective.

[0013] This object is achieved by a holding device having the features of claim 1 and by a manufacturing method having the features of claim 10.

[0014] Each energy storage cell is assigned a buffer element, so that in the coupled accumulator block, a buffer element is located between each two energy storage cells. This buffer element can also encompass or cover sections of the energy storage cells in a frame-like manner. The plastic of the buffer elements preferably has a thermal conductivity of more than 0.5 W / mK and a specific electrical resistance of more than 10 10 Ωm. Furthermore, plastics with a thermal conductivity of more than 1 W / mK and a specific electrical resistance of more than 10 15Ωm are used. Particularly preferred are plastics with a thermal conductivity of more than 2 W / mK and a specific electrical resistance of more than 10 20 Ωm. All measured values refer to room temperature. The thermal conductivity of the plastics is determined according to DIN 53612 and DIN 52613.

[0015] Each buffer element has positioning and connecting means in a first edge region. The positioning and connecting means are designed such that they maintain a periodic spacing between the buffer elements, particularly when the buffer elements are aligned parallel in a battery block along the extension direction.

[0016] The positioning and connecting means are formed in the first edge region of the buffer elements as a one-piece base connecting element extending along the direction of extension between the buffer elements.

[0017] This results in a mounting device that provides space between adjacent buffer elements for accommodating energy storage cells. The adjacent buffer elements are already arranged in a defined position and mechanically connected to one another by the positioning and connecting means integrally formed in the form of the base connecting element. Thus, no further assembly step is required to couple the assembly of an energy storage cell with an associated buffer element to a neighboring assembly of such an energy storage cell and buffer element.

[0018] In the interest of technological rationalization, it is preferable to design the buffer elements with the same geometric shape and to arrange them on one side of the base connecting element at a periodic spacing transverse to the direction of extension. This results in a comb-like structure, viewed transversely to the direction of extension, which provides mounting space for energy storage cells between the adjacent buffer elements.

[0019] According to the invention, the base connecting element is formed from a material such that it can be elastically deformed between two adjacent buffer elements to such an extent from the direction of extension that edge regions of adjacent buffer elements spaced from the base connecting element assume an extended bending distance compared to a parallel alignment of adjacent buffer elements with the periodic spacing. According to the invention, this corresponds to at least 1.5 times the value of the periodic spacing. In this way, the comb-like structure of the adjacent buffer elements can be bent open, and cells can be inserted into the resulting space. When the bending force is no longer exerted after insertion, a (light) press fit exists between the buffer elements and the cells.The further the spaced edge regions of the buffer elements are from the base connecting element, the greater the effect on the expanded bending distance between the spaced edge regions of two adjacent buffer elements when the base connecting element is deformed. Ultimately, the elastic deformation preferably results in a rotation of the buffer elements, which were originally aligned parallel to one another, about an axis of rotation arranged perpendicular to the extension axis. The buffer elements are therefore preferably all mechanically coupled to the base connecting element at the same connection regions in their first edge regions. The simple widening of the comb-like structure in this way enables uncomplicated insertion of the energy storage cell between two adjacent buffer elements without the spatial relationship between the buffer elements being canceled or having to be re-established.

[0020] All of the previously described variants of the holding device are preferably designed such that the base connecting element and the buffer elements are formed as a single piece and, in particular, are made of the same material. This allows the holding device to be manufactured particularly cost-effectively and efficiently from plastic granules or blanks using injection molding or compression molding processes. Plastic granules are used as the basis, which may contain additives, such as particles or other structures with high thermal conductivity. In particular, boron nitride particles can be added to the plastic. Boron nitride exhibits very high thermal conductivity while also providing a high electrical insulation effect. Therefore, it is predestined for the present application to impart the desired properties to the injection molding material. Silicones or silicone foams with boron nitride additives are particularly preferred.Boron nitride particles with an average diameter of more than 300 µm, preferably more than 400 µm, and particularly preferably more than 500 µm, should be used. It has been shown that in this diameter range of the boron nitride particles, the packing density of the boron nitride in the plastic matrix and thus the thermal conductivity can be maximized. Thermally conductive silicones constructed in this way act as a heat transfer medium, as permanent dielectric insulation for permanent all-round insulation of the energy storage cells, particularly against electrical voltage breakdowns, as protection against environmental influences, and as relieving shock and vibration dampers over a wide temperature and humidity range. Due to its very soft surface texture, the holding device adapts very well to the contact surfaces of the energy storage cells, thereby reducing the thermal contact resistance and the total thermal transfer resistance to the heat sink, such asa coupled heat sink or housing, without the need for auxiliary means such as thermal paste.

[0021] Likewise, for all of the previously described variants of the mounting device, it is advantageous for the buffer elements to be flat and, in particular, disc-shaped. The two-dimensional geometry of the buffer element discs corresponds to the two-dimensional geometry of the energy storage cell coupling surfaces. This maximizes the heat transfer between the energy storage cells and the buffer elements.

[0022] For all variants described above, it is advantageous that each buffer element has support means in a second edge region spaced from the first edge region of the buffer element, which support means form a supporting mechanical contact between adjacent buffer elements that acts in the direction of extension when the buffer elements are aligned parallel as viewed along the direction of extension. Suitable support means are all geometric structures that bridge the space between adjacent buffer elements at a distance from the base connecting element when the buffer elements are aligned parallel. This creates mechanical contact between the adjacent buffer elements, which preferably creates a positive connection in the second edge region. Support means can be present opposite each other on both adjacent buffer elements and interact to achieve the desired supporting effect.Or each buffer element has a support means that extends along the direction of extension to the adjacent buffer element.

[0023] In variants of the mounting device that provide support means, it is preferred that the support means form a supporting mechanical contact between adjacent buffer elements along the entire second edge region when the buffer elements are aligned parallel along the extension direction, as viewed along the extension direction. This mechanical support effect is in turn ensured by a positive connection. The second edge region is preferably arranged along the edge of the buffer element. The support means can be arranged in sections or along the entire edge contour of the buffer elements, which are spaced apart from the base connecting element.

[0024] For the reasons described above, it is particularly advantageous, in the variants of the mounting device with support means, to design these support means as a one-piece structure made of the same material as the buffer elements.

[0025] If one of the above variants uses a particularly soft plastic mixture, it is advantageous to incorporate fiberglass or spring steel inserts into the plastic of the buffer elements to increase their torsional rigidity. This prevents the buffer elements from collapsing under their own weight, thus making the comb-like structure with the energy storage cell receiving areas provided between the buffer elements inaccessible without first straightening the collapsed buffer elements. The inserts are preferably made of a heat-conducting material.

[0026] Furthermore, an accumulator block is described which has at least one of the holding devices as described here. The energy storage cells are inserted between the buffer elements. In particular, an energy storage cell is inserted between at least two of the buffer elements, preferably between two directly successive buffer elements. The energy storage cells and the buffer elements are arranged alternately in the longitudinal direction of the holding devices. The at least one energy storage cell contacts one side of a buffer element directly or via a thermally conductive connection (such as a thermally conductive layer) and preferably the sides of the buffer elements located on both sides of the energy storage cell facing the energy storage cell.For example, with the exception of the two buffer elements at the two ends of the holding device, essentially each buffer element contacts two energy storage cells, preferably one energy storage cell on each side of the respective buffer element. Furthermore, two or more than two energy storage cells can be provided between two (preferably adjacent) buffer elements. Each side of the buffer elements contacts one side of the energy storage cells. This applies in particular to the buffer elements that are not located at one end of the holding devices. The buffer elements and the energy storage cells are aligned with one another. The buffer elements and the energy storage cells preferably lie against one another with their largest side surfaces, whereby these can overlap one another. The buffer elements and the energy storage cells are aligned essentially parallel to one another.

[0027] Furthermore, a manufacturing method for an accumulator block comprising a plurality of electrically and mechanically coupled electrochemical energy storage cells is claimed, comprising the following method steps: - Providing a holding device according to one of the variants described above; - first bending the base connecting element transversely to the direction of extension such that the distance between two adjacent buffer elements is increased in areas spaced from the base connecting element, - Inserting an electrochemical energy storage cell between the two buffer elements, the distance between which has been increased at least in sections by bending the base connecting element, - Bending back the base connecting element in the direction of extension in the area of the inserted electrochemical energy storage cell, - simultaneous or subsequent further bending of a region of the base connecting element and / or buffer element adjacent to the inserted electrochemical energy storage cell in the manner of the first bending and - Repeating the steps of inserting an electrochemical energy storage cell, bending it back and further bending it until electrochemical energy storage cells are inserted between all buffer elements of the holding device.

[0028] Using the method described above, electrochemical energy storage cells can be coupled to form a battery block using the mounting device according to the invention in a particularly simple manner. This method can be easily automated and thus enables cost-effective assembly. The mounting device is preferably moved along its extension direction. This movement sequence is configured such that the base connecting element is bent in sections such that regions of adjacent buffer elements spaced apart from the base connecting element are moved apart from each other beyond the periodic spacing. An energy storage cell can be inserted or placed particularly easily between these spaced-apart buffer elements.The spread buffer elements, already equipped with an energy storage cell arranged between them, are then returned to a parallel position by bending back the base connecting element. In this position, the energy storage cell fills the entire installation space between two adjacent buffer elements. The thickness of the energy storage cell, viewed in the direction of extension of the holding device, corresponds exactly to the periodic spacing of the parallel-aligned buffer elements, within the limits of manufacturing tolerances.

[0029] Further aspects of the invention are explained with reference to two exemplary embodiments explained below: They show: Fig. 1 a side view of a first embodiment of the holding device; Fig. 2 a perspective view of the first embodiment of the holding device from Fig. 1; Fig. 3 a side view of a second embodiment of the holding device; Fig. 4 a perspective view of the second embodiment of the holding device from Fig. 3 and Fig. 5 the perspective view of the first embodiment of the holding device from Fig. 1, illustrating the assembly process of the energy storage cells into an accumulator block.

[0030] Fig. 1 shows a side view of a first embodiment of the holding device. A base connecting element 15 runs largely in a straight line along an extension direction E. In the right-hand edge region of the base connecting element 15, this is curved about a rotation axis positioned perpendicular to the extension direction E. Buffer elements 10, positioned at periodic intervals D, extend perpendicular to the extension axis E from the upper side of the base connecting element. In the straight-line region of the base connecting element 15, the buffer elements 10 are thus aligned parallel to one another. The resulting structure is thus comb-shaped. In its first edge regions 11, which for all buffer elements 10 face the base connecting element 15, the base connecting element 15 assumes the function of a positioning and connecting means between the individual buffer elements 10 arranged uniformly in a comb-like manner.In the right-hand edge region of the base connecting element 15, the distance between edge regions of the buffer elements 10 that are spaced from the base connecting element 15 is increased due to its curved shape. The periodic, uniform distance D is increased to the extended bending distance B. The amount of the extended bending distance B is naturally dependent on the distance of the edge regions in question from the base connecting element and increases linearly with increasing distance, as can be seen from a comparison of the two representations of the distance B. The distance D also designates the space that the energy storage cells take up between the buffer elements for the accumulator block. The buffer elements are arranged in the space designated as distance D in the accumulator block. Fig. 1 therefore also shows some relevant features of an exemplary embodiment of the accumulator block.

[0031] Fig. 2 shows a perspective view of the first embodiment of the holding device from Fig. 1. Identical components and their sections are provided with the same reference symbols. To avoid repetition, reference is made to the explanations for Fig. 1. In Fig. 2, the three-dimensional shape of the lateral comb-like structure of the holding device can be seen. The buffer elements 10 are designed as rectangular discs, which are arranged periodically spaced on the likewise rectangular base connecting element 15. As a result, cuboid-shaped spaces are formed between adjacent buffer elements 10 when the buffer elements 10 are aligned in parallel. These spaces serve to accommodate individual electrochemical energy storage cells. Taking into account usual manufacturing tolerances, the cuboid-shaped spaces represent the exact size of the energy storage cells to be used. The energy storage cells, periodically spaced from one another by the holding device, form an accumulator block. This is described in connection with Fig. 5 is explained in more detail.

[0032] Fig. Figure 3 shows a side view of a second embodiment of the holding device. The same components are again provided with the same reference numerals and the explanations for Fig. 1 are not repeated here but apply accordingly. Unlike the first embodiment, only the buffer elements 10 are formed in the second edge region 12. There, each buffer element has support means 13, which are designed as projections oriented in the direction of the base connecting element 15. Fig. 4 is a perspective view of the second embodiment of the mounting device of Fig. 3 that the projections 13 extend across the entire width of the upper edge of the rectangular buffer elements 10. The support means 13 of adjacent buffer elements 10 lie in a form-fitting manner with respect to one another when the buffer elements 10 are aligned parallel. As a result, the support means 13 can absorb forces occurring in the direction of extension E in addition to the base connecting element and the areas of the buffer means between their upper and lower edges. This is particularly important when installing the accumulator block in an encapsulated housing for use in the automotive sector. The structure thus serves to provide better mechanical protection, shock absorption, and vibration damping compared to the energy storage cells and ensures sufficient structural stability in the event of a crash.

[0033] In both described embodiments, the base connecting element 15 and all buffer elements 10 are constructed in one piece from the same material. This is the preferred and most advantageous variant. However, it is also conceivable to provide a structure consisting of individual parts, which can also be constructed from different materials. However, this is not shown in the figures.

[0034] Fig. 5 shows the perspective view of the first embodiment of the holding device from Fig. 1 in the already out Fig.2. Here, energy storage cells Z are inserted into most of the free spaces between adjacent buffer elements 10. During the automated loading of the holding device with energy storage cells Z, these can be used particularly well in areas where the distance between the adjacent buffer elements 10 is increased by bending the base connecting element 15. For this purpose, the energy storage cells Z can be inserted, for example, along a lateral mounting direction E1 and / or along a top-oriented mounting direction E2 into the associated free spaces between adjacent buffer elements 10. The insertion takes place in the curved sections of the base connecting element 15, which is moved there along a curved direction of movement E3. Once the free spaces there are loaded, the holding device can be moved further in a straight line along the extension direction E of the holding device.In the rectilinearly oriented area, the compact contour of the accumulator block formed by the energy storage cells Z and the holding device can be seen. List of reference symbols 10 Buffer element 11 first edge area 12 second edge area 13 Proppant 15 Base connecting element E Extension direction E1 Mounting direction from the side E2 Mounting direction from above E3 Direction of movement of holding device D periodic distance B extended bending distance Z Energy storage cell

Claims

[1] Mounting device for the adjacent arrangement of planar electrochemical energy storage cells (Z) along an extension direction (E), comprising: a plurality of buffer elements (10) made of plastic, which have a thermal conductivity of more than 0.5 W / mK and a specific electrical resistance of more than 10 10 Ωm, wherein each buffer element (10) has positioning and connecting means in a first edge region (11) and the positioning and connecting means are designed such that that they hold the buffer elements (10) at a periodic distance (D) from one another, wherein the positioning and connecting means in the first edge region (11) of the buffer elements (10) are formed as a one-piece base connecting element (15) extending along the extension direction (E) between the buffer elements (10), characterized bythat the base connecting element (15) is formed from a material such that it can be elastically deformed between two adjacent buffer elements (10) to such an extent from the direction of extension (E) that edge regions of adjacent buffer elements (10) spaced apart from the base connecting element (15) assume an extended bending distance (B) which is at least 1.5 times the value of the periodic distance (D) compared to a parallel alignment of adjacent buffer elements (10) with the periodic distance (D). [2] Holding device according to claim 1, characterized by that the buffer elements (10) are of identical geometric shape and are arranged on one side of the base connecting element (15) transversely to the direction of extension (E) at the periodic distance (D) from one another. [3] Holding device according to one of claims 1 to 2, characterized bythat the base connecting element (15) and the buffer elements (10) are formed in one piece from the same material. [4] Holding device according to one of claims 1 to 3, characterized by that the buffer elements (10) are flat. [5] Mounting device according to one of the preceding claims, characterized by that each buffer element (10) has, in a second edge region (12) spaced from the first edge region (11) of the buffer element (10), support means (13) which, when the buffer elements (10) are aligned parallel as viewed along the direction of extension (E), form a supporting mechanical contact between adjacent buffer elements (10) acting in the direction of extension (E). [6] Mounting device according to claim 5 characterized bythat the support means (13) form a supporting mechanical contact between adjacent buffer elements (10) acting in the direction of extension (E) when the buffer elements (10) are aligned parallel along the entire second edge region (12) as viewed along the direction of extension (E). [7] Holding device according to claim 5 or 6, characterized by that the support means (13) are designed as a one-piece structure made of the same material as the buffer elements (10). [8] Mounting device according to one of the preceding claims, characterized by that in order to increase the torsional rigidity of the buffer elements (10), inserts made of glass fibre or spring steel are incorporated into the plastic of the buffer elements (10). [9] Accumulator block with at least one holding device according to one of the preceding claims, wherein the accumulator block further comprises energy storage cells (Z), wherein the energy storage cells (Z) are inserted between the buffer elements (10). [10] Manufacturing method for an accumulator block comprising a plurality of electrically and mechanically coupled electrochemical energy storage cells (Z) with the following method steps: - Providing a holding device according to one of claims 3 to 8; - first bending of the base connecting element (15) transversely to the direction of extension (E) such that a distance between two adjacent buffer elements (10) is increased in regions spaced apart from the base connecting element (15), - inserting an electrochemical energy storage cell (Z) between the two buffer elements (10), the distance between which has been increased in sections by bending the base connecting element (15), - Bending back the base connecting element (15) in the direction of extension (E) in the region of the inserted electrochemical energy storage cell (Z), - simultaneous or subsequent further bending of a region of the base connecting element (15) adjacent to the inserted electrochemical energy storage cell (Z) in the manner of the first bending and - Repeating the steps of inserting an electrochemical energy storage cell (Z), bending back and further bending until electrochemical energy storage cells (Z) are inserted between all buffer elements (10) of the holding device.

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