Method for applying potting compound

Abstract

The invention relates to a method for applying potting compound (4) to at least one cell module (1) of an electrical energy storage device comprising a predetermined number of electrically connected individual cells (2). According to the invention, the potting compound (4) is applied to an upper side of the cell module (1) by means of a single-compartment or 14-compartment mixing head of a potting system in at least one predetermined travel path (V1, V1', V2, V2', V3, V4).

Description

[0001] The invention relates to a method for applying potting compound with respect to at least one cell module of an electrical energy storage device comprising a predetermined number of electrically connected individual cells.

[0002] From WO 2023 / 072523 A2, a battery fire prevention system and a method for preventing a battery fire resulting from a thermal runaway of a battery cell are known, wherein a battery of a motor vehicle comprises several battery cells.The battery fire prevention system comprises a cell degassing channel which can be connected to the battery cells and into which a gas escaping from a respective one of the battery cells can be introduced and discharged to an outlet opening of the cell degassing channel, a gas flow influencing structure as part of the cell degassing channel which is designed to influence the course of the gas flow flowing through the cell degassing channel, which gas flow is formed by the gas escaping from the first battery cell, and a cooling device for cooling the thermally permeable first battery cell, wherein the cooling device is configured such that a coolant flows through it, at the latest when the first battery cell thermally permeates.

[0003] Furthermore, DE 10 2015 102 688 A1 describes a method for providing a battery cell structure. The method comprises providing a battery cell; providing a first tab and a second tab extending from the battery cell; and providing a potting compound on the battery cell.

[0004] The invention is based on the object of specifying a method for applying potting compound with respect to at least one cell module of an electrical energy storage device.

[0005] The object is achieved according to the invention by a method which has the features specified in claim 1.

[0006] Advantageous embodiments of the invention are the subject of the subclaims.

[0007] A method for applying potting compound with respect to at least one cell module of an electrical energy storage device comprising a predetermined number of electrically connected individual cells provides according to the invention that the potting compound is applied to an upper side of the cell module by means of a 1-compartment or 14-compartment mixing head of a potting system in at least one predetermined travel path.

[0008] By applying the method, it is possible to apply the potting compound in a defined and comprehensive manner to the top side of the cell module, i.e. to provide the spaces between individual cells and on the top sides of the individual cells running in the direction of a longitudinal axis with a required respective layer thickness of potting compound.

[0009] The potting compound prevents or limits the spread of thermal runaway from one individual cell to neighboring individual cells. Applying the potting compound in this way can thus largely limit thermal runaway to the individual cell.

[0010] The encapsulation system's process program is optimized to apply a specified layer thickness to the top surface of the cell and fill the gaps between the individual cells. Such a coating of the top surface of the cell module, partially filling the gaps, can be referred to as top encapsulation.

[0011] In one embodiment of the method, during a travel movement of the single- or 14-way mixing head, a volume of dispensed potting compound is adjusted depending on the position of the single- or 14-way mixing head relative to the top side of the cell module. In particular, the volumes, i.e., the dosage amount, are adjusted depending on whether the single- or 14-way mixing head moves over the gaps between the individual cells or over the top sides of the individual cells. For example, a larger amount of potting compound is dispensed relative to the gaps than when the single- or 14-way mixing head moves over the top side of the individual cells.

[0012] In one possible embodiment, during a travel path of the single- or 14-way mixing head for sealing the gaps between individual cells, the sealing compound is dispensed in such a way that a predetermined layer thickness of, for example, approximately 5.5 mm is created. In particular, the individual cells are arranged in a cell holder and / or displacement body, by means of which the individual cells are positioned and aligned with one another, and whose surface forms an application area for the sealing compound, so that the sealing compound is filled to a specific depth into the gaps, especially between the individual cells.

[0013] In one embodiment, during a travel path of the single-cell or 14-cell mixing head for encapsulating the top surface of the individual cells, the encapsulating compound is dispensed in such a way that a predetermined additional layer thickness of, for example, approximately 1 mm is created on the top surface of the cell. In particular, the encapsulating compound is applied to the top surface of the cell in a predetermined layer thickness, covering a cell rupture disc of the respective individual cell. The layer thickness is predetermined, in particular to largely prevent thermal runaway from spreading to neighboring individual cells in the event of thermal runaway of an individual cell.

[0014] In a further embodiment of the method, the potting compound dispensed by the single- or 14-way mixing head is first introduced into at least the spaces between the individual cells, creating the specified layer thickness of, for example, approximately 5.5 mm. The potting compound is first introduced into the spaces between the individual cells, as the potting compound flows optimally in the spaces to achieve the layer thickness of, for example, approximately 5.5 mm.

[0015] In another possible design, the single- or 14-cell mixing head performs a meandering movement to introduce the casting compound into the spaces between the individual cells. This means that the spaces between the individual cells are filled in one movement, particularly with the single-cell mixing head, and the layer thickness of 5.5 mm is adjusted.

[0016] In one embodiment, the potting compound is applied to the top side of the cell module at a temperature in a temperature range of 40°C to 60°C, in particular at a temperature of approximately 50°C, so that the potting compound has sufficient flowability to distribute itself optimally over the top side of the cell module, in particular in the intermediate spaces, so that the layer thickness is achieved and the top side of the cell module is provided with the potting compound as a cover potting over its entire surface.

[0017] In a further development of the method, the travel path of the 1-way or 14-way mixing head runs in the direction of a longitudinal axis of the cell module, so that a number of the travel paths of the 1-way or 14-way mixing head are optimized to produce the cover casting of the top side of the cell module.

[0018] Embodiments of the invention are explained in more detail below with reference to drawings.

[0019] Showing: Fig. 1 schematically shows a perspective view of a cell module of an electrical energy storage device comprising several individual cells, Fig. 2 schematically shows a perspective view of the cell module with potting compound applied to a top side, Fig. 3 schematically shows a sectional view of the cell module with applied potting compound, Fig. 4 schematically shows an enlarged section of a sectional view of the cell module Fig. 5 schematically shows a top view of the cell module with a travel path of a single mixing head of a casting system, Fig. 6 schematically shows a top view of the cell module with a travel path of a 14-fold mixing head of a casting system and Fig. 7 schematically shows a top view of the cell module with alternative travel paths of a single mixing head of a casting system.

[0020] Corresponding parts are provided with the same reference numerals in all figures.

[0021] Fig. Figure 1 shows a perspective view of a cell module 1 for an electrical energy storage device, in particular for a vehicle. The electrical energy storage device is, for example, a traction battery of an electric vehicle, a hybrid vehicle, or a fuel cell-powered vehicle.

[0022] The cell module 1 has a predetermined number of cells electrically connected in series and / or parallel to one another, Fig. 3 to 7, which according to the present embodiments are arranged in the Fig. 1 to 7 are designed as round cells, i.e., they have a cylindrical cell housing 2.1. The individual cells 2 of the cell module 1 are arranged in a common housing 6, which is box-shaped.

[0023] The individual cells 2 have a so-called cell bursting disc 3 in the area of ​​a cell top, for example, incorporated in a cell lid, as shown by way of example and in a greatly simplified manner in Fig. 3. This cell rupture disc 3 is designed to burst, i.e., break open, when an individual cell 2 has an internal pressure that exceeds a predetermined threshold, in order to specifically reduce the internal pressure of the individual cell 2. Such a case is referred to as thermal runaway of the individual cell 2. The gases escaping from the cell housing 2.1 have a comparatively high temperature, so that the gases pose a fire risk for the cell module 1 and thus also for the electrical energy storage device.

[0024] In order to prevent as far as possible that neighboring individual cells 2 of the defective individual cell 2 also thermally break down, it is provided that an upper side of the cell module 1 is provided with a potting compound 4, which is, for example, a thermally conductive epoxy resin and / or polyurethane. Fig. 2 a perspective view of the cell module 1 with applied potting compound 4.

[0025] Fig. 3 shows a sectional view of one of the cell modules 1 with potting compound 4 and cell holder 5, wherein in Fig. 4 shows a sectional view of an enlarged section of the cell module 1 with potting compound 4 and cell holder 5.

[0026] The individual cells 2 of the cell module 1 are aligned and positioned by means of a cell holder 5, alternatively or additionally by means of a displacement body, so that, for example, a predetermined distance between adjacent individual cells 2 can be set. The cell holder 5, which extends essentially over the entire surface of the cell module 1, is arranged in the region of an upper half of the cell housing 2.1 of the individual cells 2, wherein a defined distance is set between a surface side of the cell holder 5 and a cell top side of the individual cells 2. The cell holder 5 is thus predefinedly positioned with respect to the individual cells 2.

[0027] For example, the cell holder 5 is plate-shaped and has a number of recesses corresponding to the number of individual cells 2, the shape of which corresponds to a shape of the cell housing 2.1 of the individual cells 2. The respective individual cell 2 is in particular pushed into a recess A, whereby a positive connection is established between the cell housing 2.1 and the recess A, i.e., the cell holder 5.

[0028] In order to ensure that the potting compound 4 is applied in a defined manner to the top side of the cell module 1, the cell module 1 is fed to a potting system (not shown in detail), wherein the potting compound 4 is applied to the top side of the cell module 1 by means of a 1-compartment mixing head or a 14-compartment mixing head.

[0029] An upper side of the cell holder 5 forms a support surface for the potting compound 4, which is introduced in particular into spaces Z, in particular in the direction of a longitudinal axis of the cell module 1, between rows of adjacent individual cells 2.

[0030] In particular, the cell holder 5 is arranged with respect to the individual cells 2 of the cell module 1 such that a predetermined layer thickness S1 of the potting compound 4 in the region of the gaps Z is approximately 5.5 mm. A predetermined further layer thickness S2 of the potting compound 4 applied to the cell tops is approximately 1 mm, wherein by means of the potting compound 4 a comprehensive cover potting is formed on the top side of the cell module 1, as in Fig. 2 is generated.

[0031] Fig. 5 shows a top view of the cell module 1 with travel paths V1, V2 of a 1-compartment mixing head and in Fig. Figure 6 shows a top view of cell module 1 with travel paths V3 and V4 of a 14-way mixing head. Travel paths V1 to V4 each form a so-called potting line.

[0032] According to the Fig. In the embodiment shown in Figure 5, the travel paths V1, V2 run according to a Fig. 7 shown travel direction R.

[0033] A first travel path V1 is provided in particular for closing the gaps Z, on the one hand between a housing wall 6.1 of the housing 6 of the cell module 1 and on the other hand between individual cells 2, which are arranged substantially in a row along the longitudinal axis of the cell module 1.

[0034] Along the first travel path V1, in particular along the gaps Z between the housing wall 6.1 and the individual cells 2, the potting compound 4 is dispensed with a volume of approximately 12 ml or with a volume of approximately 14 ml, depending on the length of the cell module 1, and applied into the gap Z. The higher volume of the dispensed potting compound 4 is assigned to the longer cell module 1.

[0035] Along the first travel path V1 for applying the potting compound 4 into spaces Z between the individual cells 2 along the travel direction R, in particular in the direction of the longitudinal axis of the cell module 1, the potting compound 4 is dispensed with a volume of approximately 10.23 ml or with a volume of approximately 12.5 ml depending on a length of the cell module 1 and applied into the space Z.

[0036] A second travel path V2 of the single-compartment mixing head of the casting system runs directly above the cell tops of the individual cells 2, for example directly above the respective cell rupture disc 3.

[0037] On a second travel path V2, which is arranged closest to the first travel path V1 facing the housing wall, the potting compound 4 is dispensed with a volume of approximately 6.55 ml or with a volume of 8 ml depending on a length of the cell module 1 and applied to the top sides of the cells.

[0038] On the remaining second travel paths V2 of the single-compartment mixing head, the potting compound 4 is dispensed with a volume of approximately 8.2 ml or approximately 6.71 ml in order to completely seal the top side of the cell module 1 with the potting compound 4.

[0039] The potting compound 4 is applied to the top of the cell module 1 at a temperature of approximately 50°C, whereby the gaps Z are first filled with the potting compound 4, which improves the flow of the potting compound 4 in the gaps Z. The dosing speed at which the potting compound 4 is applied is the same on all travel paths V1, V2 of the single-compartment mixing head.

[0040] Fig. 6 shows the travel paths V3, V4 of the 14-way mixing head of the potting system, with which the potting compound 4 is applied over the entire surface, in particular over the entire surface, of the top side of the cell module 1.

[0041] The potting compound 4 is dispensed along a third travel path V3 for applying the potting compound 4 into the spaces Z between the housing wall 6.1 and a row of individual cells 2 arranged along this, depending on a length of the cell module 1, with a volume of approximately 11.8 ml or a volume of approximately 15 ml.

[0042] Along the third travel paths V3 between the third travel paths V3 facing the housing walls 6.1, the potting compound 4 is introduced into the spaces Z between the rows of individual cells 2 with a volume of approximately 10.6 mm or with a volume of approximately 13.4 ml, depending on the length of the cell module 1.

[0043] Along fourth travel paths V4, the potting compound 4 is dispensed with a volume of approximately 4.5 ml or with a volume of 5.8 ml depending on a length of the cell module 1 and applied to the cell tops of the individual cells 2, wherein the further layer thickness S2 of the potting compound 4 is approximately 1 mm.

[0044] Thus, a closed cover potting is created on the top side of the cell module 1, wherein the potting compound 4 applied over the entire surface largely prevents the spread of thermal runaway.

[0045] In Fig.Figure 7 shows a top view of the cell module 1 with alternative travel paths V1', V2' of a single mixing head of the casting system.

[0046] The single-compartment mixing head is provided to follow a first travel path V1' in a meandering manner, so that the potting compound 4 is dispensed in a travel movement to fill the gaps Z between housing walls 6.1 and individual cells 2, as well as between rows of individual cells 2. For example, it is also possible here to vary the volume of the potting compound 4 to be dispensed by the single-compartment mixing head according to a position of the single-compartment mixing head relative to the top side of the cell module 1.

[0047] Respective second travel paths V2', which run between two respective first travel paths V1' over the cell tops of the individual cells 2, are traversed by means of the single-compartment mixing head in such a way that one side of the cell module 1, in particular a further housing wall 6.2 of the housing 6, at which a second travel path V2' ends, represents a start of a further second travel path V2', which ends on an opposite side of the cell block 1 and thus on an opposite further housing wall 6.2. List of reference symbols 1 cell module 2 single cells 2.1 Cell housing 3 Cell rupture disc 4 Potting compound 5 cell holders 6 housings 6.1 Housing wall 6.2 additional housing wall R travel direction S1 layer thickness S2 additional layer thickness V1, V1' first travel path V2, V2' second travel path V3 third travel path V4 fourth travel path Z space QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2023 / 072523 A2

[0002] DE 10 2015 102 688 A1

[0003]

Claims

[1] Method for applying potting compound (4) with respect to at least one cell module (1) of an electrical energy storage device comprising a predetermined number of electrically connected individual cells (2), characterized by that the potting compound (4) is applied to an upper side of the cell module (1) by means of a 1-compartment or 14-compartment mixing head of a potting system in at least one predetermined travel path (V1, V1', V2, V2', V3, V4). [2] Method according to claim 1, characterized by that during a movement of the 1-way or 14-way mixing head, a volume of a dispensed potting compound (4) is adjusted depending on a position of the 1-way or 14-way mixing head in relation to the top side of the cell module (1). [3] Method according to claim 2, characterized bythat during a travel path (V1, V1', V3) of the 1-way or 14-way mixing head for casting gaps (Z) between individual cells (2), the casting compound (4) is dispensed in such a way that a predetermined layer thickness (S1) is produced. [4] Method according to claim 2 or 3, characterized by that during a travel path of the 1-way or 14-way mixing head for potting a cell top side of the individual cells (2), the potting compound (4) is dispensed in such a way that a predetermined further layer thickness (S2) is produced on the cell top side. [5] Method according to claim 3 or 4, characterized by that the casting compound (4) dispensed by means of the 1-way or 14-way mixing head is first introduced into the spaces (Z) at least between the individual cells (2) and the predetermined layer thickness (S1) is produced. [6] Method according to one of claims 3 to 5, characterized bythat a meandering movement is carried out by means of the 1-way or 14-way mixing head to introduce the casting compound (4) into the spaces (Z) between the individual cells (2). [7] Method according to one of the preceding claims, characterized by that the potting compound (4) is applied to the top of the cell module (1) at a temperature in a temperature range of 40°C to 60°C. [8] Method according to one of the preceding claims, characterized by that the travel path (V1, V1', V2, V2', V3, V4) of the 1-way or 14-way mixing head runs in the direction of a longitudinal axis of the cell module (1).

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