Lid assembly, energy storage cell, battery module and method of manufacturing the lid assembly

Abstract

A lid assembly that prevents excessive pressure within a cell housing, an energy storage cell, a battery module, and a method for manufacturing the lid assembly are provided. A lid assembly (140) for an Ethel housing, the lid assembly (140) comprising: a fastening assembly 200 with an opening 220 and a closure plate 120 with a groove 210; a first closing element 230, which is pierced to close the opening 220 before filling the cell housing and for filling the cell housing with a filling element capable of filling the electrolyte into the cell housing; a second closure element 240 for closing the opening 220 after filling of the cell housing; It is equipped with The circumferential groove 210 is configured in such a way that the closure plate 120 can break in the area of ​​the groove 210 if a certain overpressure is reached or exceeded in the cell housing.

Description

[Technical Field]

[0001] The present invention relates to a lid assembly, an energy storage cell, a battery module and a method for manufacturing the lid assembly. [Background technology]

[0002] In the field of energy storage cells, particularly battery cells, especially lithium-ion battery cells, cylindrical, prismatic, and pouch-shaped battery cells are known, among others. Battery cells for storing electrical energy play a central role in the so-called electromobility field, both in vehicles with purely electric drives and in vehicles with hybrid drives. For example, a battery module for a 12V starter battery can have four battery cells, while a high-voltage storage unit can have several battery modules.

[0003] A battery cell may have an energy storage element and electrodes connected to it arranged inside the cell housing. Electrical power can be extracted (utilized) from outside the cell housing via an established electrical connection with the electrodes. The energy storage element may have chemical bonds (compounds) that can lead to gas evolution inside the cell housing. At the same time, high temperatures can create high pressures inside the cell housing, which increases the risk of thermal runaway of the battery cell. Summary of the Invention [Problem to be solved by the invention]

[0004] An object of the present disclosure is to provide a lid assembly, an energy storage cell, a battery module, and a method for manufacturing the lid assembly that improves upon the above-mentioned problems. [Means for solving the problem]

[0005] The problem is solved by a lid assembly, an energy storage cell, a battery module and a method for manufacturing the lid assembly according to claim 1.

[0006] A first aspect of the solution relates to a lid assembly for a cell housing of an energy storage cell, the lid assembly being configured, in an attached state, to allow filling of the cell housing with electrolyte, the lid assembly comprising: (i) a closure plate having a fixing assembly with an opening; (ii) the closure plate further comprising a circumferential groove; (iii) a first closure element configured to close the opening before filling of the cell housing and to be pierced for filling of the cell housing with a filling element capable of filling the cell housing with electrolyte; and (iv) a second closure element configured to close the opening after filling of the cell housing; and (v) the circumferential groove being configured to allow rupture of the closure plate in the area of ​​the groove when a predetermined overpressure in the cell housing is reached or exceeded, such that at least partial release of electrolyte is possible through the ruptured area.

[0007] As used herein, the terms "comprises," "includes," "includes," "comprises," "has," "has," "having," or other variations thereof are intended to cover a non-exclusive inclusion. Thus, for example, a method or apparatus containing or comprising a list of elements is not necessarily limited to those elements and may include other elements not expressly listed or that are inherent to such method or apparatus.

[0008] Also, unless expressly stated to the contrary, the term "or" refers to an inclusive "or" and not an exclusive "or." For example, condition A or B is satisfied by one of the following conditions: A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), and both A and B are true (or exist).

[0009] As used herein, the terms "ein" or "eine" are defined as "one or more." The terms "ein anderer" and "ein weiterer" and other variations thereof are to be understood as meaning "at least one another."

[0010] The term "plurality" as used herein should be understood to mean "two or more".

[0011] As used herein, the terms "configured" or "configured" to perform a predetermined function (and its variations) should be understood to mean that the corresponding device is already capable of performing the function, or at least that the device can be set, i.e., configured, to perform the function after appropriate configuration. Here, configuration can be achieved, for example, by appropriate setting of process parameters or by switching or similarly activating or deactivating a function or setting. In particular, the device has a number of predetermined configurations or operating modes, and can be configured by selecting one of the configurations or operating modes.

[0012] The term "electrode group" as used herein is to be understood as a device used to store chemical energy and release electrical energy, in particular as an assembly of a galvanic cell, in particular a battery cell. For this purpose, the electrode group comprises at least two electrodes, i.e., one anode and one cathode, and a separator, in particular an electrically insulating separator, which can at least partially accommodate the electrolyte. The anode, separator, and cathode are then wound around an axis to form an electrode group. Before the release of electrical energy, the stored chemical energy is converted into electrical energy. During charging of the cell, electrical energy supplied to the electrode group is converted into chemical energy and stored. Particularly preferably, several electrodes are connected to each other, in particular electrically.

[0013] The term "separator layer" or "separator" as used herein is to be understood as an electrically insulating device that separates and spaces the anode from the cathode. Preferably, the separator layer is applied to the anode layer and / or the cathode layer. Preferably, the separator layer is formed as an independent body. The separator layer or separator can also at least partially accommodate an electrolyte, which preferably contains lithium ions. The electrolyte can also be electrochemically connected to adjacent layers of the electrode stack. Preferably, the shape of the separator essentially corresponds to the shape of the anode of the electrode stack. Preferably, the separator is formed as a thin-walled, particularly preferably microporous, film. Preferably, the separator layer or separator is wetted with an additive that also improves the mobility of the separator layer or separator. Particularly preferably, the wetting is performed by an ionic additive. Preferably, the separator layer or separator extends at least partially over the defining edge of at least one electrode. Particularly preferably, the separator layer or separator extends over all defined edges of adjacent electrodes.

[0014] The term "electrolyte" as used herein should be understood to mean, in particular, a liquid or solid material capable of conducting ions and thereby enabling the transport of electrical current between the electrodes of a battery, in particular between the cathode and the anode. Unlike the electronic conductivity (by electrons) of electrode materials, electrolytes must have ionic conductivity, i.e., they must conduct electrical current by transporting charged atoms or molecules (ions). Advantageously, electrolytes are chemically stable against decomposition over a wide temperature range and electrochemically stable over as large a voltage range as possible. Ideally, electrolytes are non-toxic and non-flammable, and have at least a high flash point and a low heat of combustion. Liquid systems may be preferred over polymer electrolytes and solid electrolytes due to their better conductivity.

[0015] The energy storage cell of the first embodiment achieves the following: when a predetermined pressure in the cell housing is reached or exceeded, the closure plate can be broken in the area of ​​the peripheral groove when the lid assembly is attached to the cell housing of the energy storage cell. This prevents further buildup of pressure in the cell housing. This preferably achieves a controlled, managed, and therefore reliable pressure release (decompression). This allows the lid assembly not only to reliably and reliably fill the electrolyte under normal conditions, but also to reduce excess pressure in the cell that may occur, for example, as a result of intense heating due to a short circuit inside the cell. Furthermore, the lid assembly can be manufactured separately from the cell housing. This can be advantageous during installation of the lid assembly on the cell housing, since the opening, first closure element, fastening assembly, and groove can already be positioned or formed before the lid assembly is fixed to the cell housing. Following electrolyte filling, the opening is closed only by the second connecting element. If the lid assembly is already fixed to the cell housing, the formation of openings, for example by a drilling process, can allow dirt, especially metal shavings, into the cell housing, which can impair the function of the energy storage cell, which can be avoided by separate manufacturing of the lid assembly.

[0016] Preferred embodiments of the lid assembly are described below, which may be combined with each other as appropriate and with other aspects as further described, unless expressly excluded or technically impossible.

[0017] In some embodiments, the first closure element comprises a diaphragm and / or film attached to the opening. Here, a diaphragm or film is preferably understood to mean a thin, flat structure, for example, made of synthetic resin, rubber, metal, or other material, or a combination of two or more different materials with a planar extension large compared to its thickness. This allows for good sealing of the opening, on the one hand, and good penetration of the first closure element, on the other hand. Preferably, the diaphragm or film is made of an elastic material. This allows for no or relatively little leakage of electrolyte or solvent at the point where the filling element penetrates the diaphragm or film.

[0018] In some embodiments, the first closure element is configured to be pierced and / or pierced by a filling element formed as a hollow needle for filling the cell housing, thereby allowing filling of the closed cell housing to occur.

[0019] In some embodiments, the second closure element is configured to be matingly coupled, in particular by screwing, to close, in particular seal, the opening. For example, the opening can have an internal thread and the second closure element can have an external thread, so that the second closure element can be screwed onto the opening. This makes it particularly easy to achieve reliable sealing of the opening after filling with the energy storage cell.

[0020] In some embodiments, the second closure element is configured to be connected in a materially (welded) manner, in particular by welding and / or soldering, to close, in particular seal, the opening. For example, for this purpose, the second closure element can be provided with a flange that is welded or soldered to the fastening assembly of the filling connection. This also makes it particularly easy to achieve reliable sealing of the opening after filling the cell.

[0021] In some embodiments, the first closure element is removably attached at the opening so that the first closure element can be at least partially removed, particularly pushed out, from the opening by excess pressure. For example, the opening can be provided with a groove around the opening, which holds the first closure element. When the excess pressure in the cell exceeds a predetermined value, the first closure element can be removed from the groove around the opening, thereby reducing the excess pressure in the cell housing.

[0022] In some embodiments, the second closure element comprises a rupture diaphragm or rupture disk configured to at least partially open or release the opening to allow at least partial release of electrolyte through the opening when a predetermined overpressure is reached or exceeded in the cell housing. The rupture diaphragm or rupture disk is made of a suitable material, such as aluminum, an aluminum alloy, steel, or PTFE, and is configured to rupture and / or release the opening when the predetermined overpressure in the cell is reached or exceeded. This preferably achieves a controlled, managed, and therefore reliable pressure release (decompression). This allows the lid assembly to reduce overpressure in the cell, which may occur, for example, as a result of strong heating due to a short circuit inside the cell.

[0023] A second aspect of the solution relates to an energy storage cell comprising (i) a cell housing, (ii) two electrodes arranged within the cell housing, and (iii) a lid assembly according to the first aspect, the lid assembly being fixed to the cell housing so that the cell housing is closed in a particularly airtight manner.

[0024] A third aspect of the solution relates to a battery module having a plurality of energy storage cells according to the second aspect.

[0025] A fourth aspect of the solution relates to a motor vehicle having an electric or hybrid drive and a battery module according to the third aspect.

[0026] A fifth aspect of the solution relates to a method for producing a lid assembly according to the first aspect, comprising the steps of: (i) providing a closure plate having a circular base surface and a longitudinal axis extending perpendicular to the circular base surface; (ii) forming a through opening essentially centrally located along the longitudinal axis in the circular closure plate; (iii) forming a circumferential groove in the surface of the circular closure plate with respect to the longitudinal axis; (iv) arranging a fixing assembly in the edge area of ​​the opening; (v) arranging a first closure element for closing the opening, the first closure element being configured in an attached state to close the opening before filling the cell housing with electrolyte and to be pierced, in particular to be pierced or pierced, for filling the cell housing with a filler element capable of filling the cell housing with electrolyte; and (vi) arranging a second closure element configured in an attached state and to close the opening after filling the cell housing, following filling of the cell housing.

[0027] The features and advantages described with respect to the first aspect of the solution apply correspondingly to the other aspects described.

[0028] Further advantages, features and applicability will become apparent from the following description of preferred embodiments taken in conjunction with the drawings. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a diagram schematically illustrating a battery cell according to a first embodiment. [Figure 2] 1A and 1B are diagrams illustrating a lid assembly according to a first embodiment; [Figure 3A]3A to 3C are diagrams illustrating the manufacturing stages of the lid assembly according to the first embodiment. [Figure 3B] 3A to 3C are diagrams illustrating the manufacturing stages of the lid assembly according to the first embodiment. [Figure 3C] 3A to 3C are diagrams illustrating the manufacturing stages of the lid assembly according to the first embodiment. [Figure 3D] 3A to 3C are diagrams illustrating the manufacturing stages of the lid assembly according to the first embodiment. [Figure 4] 1 is a flowchart illustrating a preferred embodiment of a method for manufacturing a battery cell. DETAILED DESCRIPTION OF THE INVENTION

[0030] In the various figures, the same reference numbers are used throughout to refer to the same or corresponding elements.

[0031] FIG. 1 shows a schematic diagram of a battery cell 100 according to one embodiment. The battery cell 100 includes a hollow cylindrical cell housing 110 having a longitudinal axis L. The cell housing 110 may also be cubic. The cell housing 110 is made of an electrically conductive material. However, it is also conceivable that the cell housing 110 is made of an electrically insulating material. The cell housing 110 is closed on one side by a bottom plate 130. The cell housing 110 is closed on the side opposite the bottom plate 130 by a lid assembly 140. The lid assembly 140 includes a closure plate 120, which is shown in detail in FIG. 2. The closure plate 120 is arranged in a peripheral groove of the cell housing 110. Between the closure plate 120 and the groove, an electrically insulating element 150 is arranged, which electrically insulates the closure plate 120 from the cell housing 110. In addition, the electrically insulating element 150 acts as a gas-tight seal, so that the cell housing 110 can be hermetically closed by the lid assembly 140, where the opening of the groove faces towards the longitudinal axis L.

[0032] However, it is also conceivable not to arrange an electrically insulating element 150 between the closing plate 120 and the groove. This is sensible if the cell housing 110 comprises an electrically insulating material. Furthermore, it is conceivable that an electrode of one polarity is guided through the bottom plate 130 of the cell housing 110, with a penetration being arranged electrically insulated with respect to the cell housing 110 and attached to the bottom plate 130. In this case too, the lid can be directly connected to the cell housing 110, in particular by welding.

[0033] An electrode group (electrode wound group) 160 is disposed in the cell housing 110. The electrode group 160 includes an electrode 170 having a first positive polarity and an electrode 175 having a second negative polarity. However, the electrode group 160 can also be configured such that the first polarity is negative and the second polarity is positive. The electrode group 160 is disposed in the cell housing 110 such that the positive polarity electrodes 170 and the negative polarity electrodes 175 are alternately arranged in the radial direction. Separators 180 are disposed between the positive polarity electrodes 170 and the negative polarity electrodes 175, respectively, so that the electrodes 170, 175 of different polarities are electrically insulated from each other, and the separators 180 are made of an electrically insulating material. An electrolyte (electrolyte, electrolytic solution) 190 is also shown schematically within the cell housing 110. The electrolyte 190 is filled into the cell housing 110 through the lid assembly 140.

[0034] 2 shows a schematic representation of a lid assembly 140 according to one embodiment. The lid assembly 140 comprises a closure plate 120. The closure plate 120 comprises a groove 210 circumferentially disposed about a longitudinal axis L. The groove 210 has a triangular cross section, which may also have a semicircular, rectangular or other shape. In the region of the groove 210, the closure plate 120 has a thickness that is smaller than the thickness of the closure plate 120 at the time of manufacture, which allows the closure plate 120 to be more easily broken in this region.

[0035] The closure plate 120 is provided with a fixing assembly 200 having an opening 220 that is essentially centrally located with respect to the closure plate 120. The fixing assembly 200 is arranged symmetrically with respect to the longitudinal axis L. The fixing assembly 200 includes a first support ring 203 arranged on one side of the closure plate 120 and a second support ring 207 arranged on the other side of the closure plate 120. The opening 220 is closed by a diaphragm 230. Instead of the diaphragm 230, the opening 220 can also be closed by a film. The electrolyte 190 can be filled into the cell housing 110 through the diaphragm 230 using a filling tool, in particular a hollow needle (not shown here), that is suitable for piercing the diaphragm 230. After filling and after the filling tool is removed from the cell housing 110 and the diaphragm 230, the diaphragm 230 is closed. This closure should prevent a significant amount of the electrolyte 190 from leaking from the cell housing 110. In the case of an electrolyte 190 whose boiling point is below room temperature, boiling can be achieved. However, the closure of the diaphragm 230 is sufficient only for the filling process. During operation of the battery cell 100, a stable and permanent closure is required. For this purpose, an additional lid 240 is provided, which may have metal and is hermetically fixed to the fixing assembly 200.

[0036] In the event of excessive pressure in the closed cell housing 110, the closing plate 120 is configured to break in the area of ​​the groove 210, thereby allowing the gas or electrolyte 190 to also escape from the cell housing 110 and preventing a further pressure buildup.

[0037] 3A-3D show a schematic representation of the manufacture of a lid assembly according to one embodiment.

[0038] 3A, the closure plate 120 is shown in a side view with a longitudinal axis L. The longitudinal axis L extends essentially perpendicular to the closure plate 120 in the side view of the closure plate 120.

[0039] In Fig. 3B, the closure plate 120 has an essentially centrally located opening 220. A first support ring 203 is fixed to one side of the opening 220. The fixing is preferably formed by material connection (welding). The first support ring 203 is arranged axisymmetrically with respect to the longitudinal axis L. The closure plate 120 further comprises a circumferential groove 210, which is arranged further radially outward than the first support ring 203 with respect to the longitudinal axis L. The opening 220 is closed by a diaphragm 230 which rests on the first support ring 203 at the opening 220.

[0040] 3B, a second support ring 207 is also attached to the other side of the opening 220, preferably by material bonding. The diaphragm 230 is thus arranged between the first support ring 203 and the second support ring 207.

[0041] The arrangement shown in Figure 3D corresponds to the arrangement in Figure 2. Compared to Figure 3C, the cover 240 is fixed in the upper area of ​​the fixing assembly 200 relative to the plane of the paper.

[0042] It is also conceivable that instead of the first support ring 203 and the second support ring 207, the fastening assembly 200 is formed in one piece and has a circumferential groove. In this case, the groove is partially open so that the diaphragm 230 can be placed in the groove. In this case, the diaphragm 230 is preferably deformable. The opening can then be closed by mechanical deformation. The one-piece fastening assembly 200 can be correspondingly fixed inside the opening 220 by material bonding (not shown here).

[0043] FIG. 4 shows a flow chart 400 illustrating one embodiment of a method for manufacturing one embodiment of the lid assembly 140.

[0044] The first step 410 of the method involves providing a closure plate 120 having a circular base surface and a longitudinal axis L extending perpendicular to the circular base surface.

[0045] A further step 420 of the method involves the formation of a through opening 220, which is essentially centrally located along the longitudinal axis L in the circular closure plate 120. The opening 220 can in particular be formed by a drilling step.

[0046] A further step 430 of the method involves the formation of a circumferential groove 210 in the surface of the circular closing plate 120, with respect to the longitudinal axis L. The circumferential groove 210 can be formed in particular by milling or laser engraving.

[0047] A further step 440 of the method involves positioning the fixing assembly 200 in the edge area of ​​the opening 220. In particular, the fixing assembly 200 can comprise a first support ring 203 and a second support ring 207, during which one of the support rings 203, 207 is fixed to the closure plate 120 and the other support ring 203, 207 is provided.

[0048] A further step 450 of the method involves the positioning of a diaphragm 230 closing the opening 220, the diaphragm 230 being configured in the installed state to close the opening 220 before filling the cell housing 110 with electrolyte 190 and to be pierced, in particular to be pierced or pierced, for filling the cell housing 110 with a filling element capable of filling the electrolyte 190 into the cell housing 110. When the opening is closed, the diaphragm 230 is placed on support elements 203, 207 fixed to the closing plate 120.

[0049] In a further step 450, the provided further support ring 203, 207 is placed in the opening 220 under contact pressure and connected to the closure plate 120 in a materially bonded manner, such that the diaphragm 230 is arranged between the two support rings 203, 207. It is also conceivable that one or both of the support rings 203, 207 are snap-connected to the closure plate 120. The materially bonded connection can be made by a welding process, and the snap-connected connection can be made by a threaded connection.

[0050] A further step 470 of the method involves placement of a lid 240 following filling of the cell housing 110, configured to close the opening 220 in the attached state and after filling of the cell housing 110.

[0051] While at least one exemplary embodiment has been described above, it should be noted that numerous further aspects exist. It should be noted that the exemplary embodiment described above provides only non-limiting examples and is not intended to limit the scope, applicability, or configuration of the apparatus and methods described herein. Rather, the foregoing description provides guidance to those skilled in the art for implementing at least one exemplary embodiment, and it should be understood that various changes can be made in the function and arrangement of elements described in the exemplary embodiment without departing from the subject matter defined in the appended claims, respectively, and the legal equivalents thereof. [Explanation of symbols]

[0052] 100 battery cells 110 Cell housing 120 Closure Plate 130 bottom plate 140 Lid Assembly 150 insulating elements 160 electrode groups 170 Positive polarity electrode 175 negative polarity electrode 180 Separator 190 Electrolyte 200 Fixed Assembly 203 First support ring 207 Second Support Ring 210 Groove 220 Opening 230 diaphragm 240 Lid 400 Flowchart illustrating one embodiment of a method for manufacturing a lid assembly 410 Closure Plate Provision 420 Formation of an essentially centrally located through-hole 430 Formation of a circumferential trench 440 Fixation Assembly Placement 450 Diaphragm Placement 460 Fixed Assembly Joint 470 Lid placement

Claims

1. A lid assembly (140) for a cell housing (110) of an energy storage cell (100), wherein the lid assembly (140) is configured such that the cell housing (110) can be filled with an electrolyte (190) while it is installed, and the lid assembly (140) is configured A closing plate (120) having a fixed assembly (200) with an opening (220), the closing plate (120) further comprising a groove (210) provided around it, A first closing element (230) is configured to close the opening (220) before filling the cell housing (110), and to penetrate for filling the cell housing (110) with a filling element that can fill the cell housing (110) with an electrolyte (190), A second closing element (240) is configured to close the opening (220) after the cell housing (110) has been filled, and It is equipped with, A lid assembly (140) characterized in that, when a predetermined excess pressure is reached or exceeded in the cell housing (110), the circumferential groove (210) is configured to allow the closing plate (120) to rupture within the range of the groove (210), so that at least a partial release of the electrolytic material (190) is possible through the ruptured area.

2. The lid assembly (140) according to claim 1, characterized in that the first closing element (230) comprises a diaphragm and / or film attached to the opening (220).

3. The lid assembly (140) according to claim 1 or 2, characterized in that the first closing element (230) is configured to be pierced and / or inserted by a filling element formed as a hollow needle for filling the cell housing (110).

4. The lid assembly (140) according to claim 1 or 2, characterized in that the second closing element (240) is configured to be fitted into the fixed assembly (200) in order to close the opening (220).

5. The lid assembly (140) according to claim 1 or 2, characterized in that the second closing element (240) is configured to be materially bonded to the fixed assembly (200) in order to close the opening (220).

6. The lid assembly (140) according to claim 1 or 2, characterized in that the first closing element (230) is removably mounted in the opening (220) so that the first closing element (230) can be removed from the opening (220) by excessive pressure.

7. The lid assembly (140) according to claim 1 or 2, wherein the second closing element (240) comprises a fractured diaphragm or fractured disc, the fractured diaphragm or fractured disc is configured to at least partially open or release the opening (220) in order to allow at least partial release of the electrolytic material (190) through the opening (220) when a predetermined excess pressure is reached or exceeded in the cell housing (110).

8. Cell housing (110) and The cell housing (110) has two electrodes (170, 175) arranged within it, The lid assembly (140) according to claim 1 or 2 and It is equipped with, An energy storage cell (100) characterized in that the lid assembly (140) is fixed to the cell housing (110) so that the cell housing (110) is closed.

9. A battery module having a plurality of energy storage cells (100) as described in claim 8.

10. A motorized vehicle having an electric drive unit or a hybrid drive unit and the battery module described in claim 9.

11. The steps include providing a closing plate (120) having a circular base surface and a longitudinal axis (L) extending perpendicularly to the circular base surface, The steps include forming a through-opening (220) essentially located in the center along the longitudinal axis (L) of the circular closing plate (120), The steps include forming a groove (210) on the surface of the circular closing plate (120) with respect to the longitudinal axis (L), The steps include: positioning a fixed assembly (200) in the edge area of ​​the opening (220); A step of arranging a first closing element (230) for closing the opening (220), wherein the first closing element (230) is configured to be particularly through or pierced so as to close the opening (220) in the installed state before filling the cell housing (110) with the electrolyte (190), and so as to penetrate for filling the cell housing (110) with a filling element that can fill the cell housing (110) with the electrolyte (190), The steps include: positioning the second closing element (240), which is configured to close the opening (220) in an installed state and after the cell housing (110) is filled, following the filling of the cell housing (110); A method for manufacturing a lid assembly (140) having the following.

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