Lithium-ion battery cell and methods for manufacturing such a battery cell

Abstract

The invention relates to a lithium-ion battery cell, in the cell housing (1) of which an electrode / separator arrangement is arranged, wherein during the manufacture and / or operation of the battery cell in the cell housing (1) a gas formation takes place, for example O 2 -, H 2 -, HF-, CO- and / or CO 2 containing gas. According to the invention, at least one reactive element (17) made of preferably lithium is arranged in the cell housing interior to eliminate the gas formed, which reactive element forms an ionic compound with the gas formed, i.e., in particular, reacts to form lithium salts.

Description

[0001] The invention relates to a lithium-ion battery cell according to the preamble of claim 1 and a method for its production according to the preamble of claim 10.

[0002] Such a lithium-ion battery cell has an electrode / separator arrangement in its cell housing. During production and / or operation of the battery cell, gas formation occurs in the cell housing, such as O 2 -, H 2 -, HF-, CO- and / or CO 2 -containing gas.

[0003] The invention is based on the following five problems: The first problem concerns normal cell operation: During cell operation, oxygen is generated by the movement of nickel into the lithium space. Free oxygen can lead to an exothermic oxidation reaction with the electrolyte or to a fire in the presence of sparks and a flammable medium such as the electrolyte. Oxygen is generally bound by nickel, manganese, and cobalt (transition metals) in the cathode. During charging, the nickel ion occupies the vacant lithium space and releases oxygen. Manganese also tends to release oxygen in the spinel LMO electrode. In this case, manganese ions move toward the anode. This effect accelerates at high voltage and high temperature. This means that oxygen is normally released from the active materials of the cathode.This oxygen can react with the flammable electrolyte and trigger an exothermic oxidation reaction that leads to thermal runaway and the formation of carbon monoxide. It is also possible for the oxygen to react with hydrogen and generate moisture. This moisture reacts with lithium and converts into irreversible lithium hydroxide.

[0004] Copper and aluminum substrates are used for the anode and cathode. These also react with oxygen during storage and form copper and aluminum oxides. This copper oxide can be released at low voltage in the anode (reduction of the anode). Aluminum oxide can be released when the lithium salt and electrolyte react with the aluminum substrate. This means that copper and the aluminum substrate can also release oxygen.

[0005] At some point during battery operation, the seal strength weakens, and the seal becomes permeable to air. This means that oxygen can penetrate the enclosure even through the weakest point of the seal. Free oxygen is undesirable in a battery, as it can lead to thermal expansion. Oxygen should only be present in the oxide state, or there should be a mechanism to capture this oxygen. Currently, there is no entrapment of free oxygen in the cell.

[0006] A second problem concerns hydrogen, which is generated by the moisture content in the cell: Most cell components have some moisture. The largest part of this is found in the separator. It contains about 400 ppm of moisture. It is not possible to completely remove the moisture because the active material, such as nickel, retains the moisture in its crystals. At a voltage of more than 1.2 volts, the moisture is converted to H 2 and O 2 electrolyzed. This means that 4 V of a lithium-ion cell is sufficient to electrolyze moisture and produce hydrogen and oxygen.

[0007] Hydrogen is also produced by the breaking of ethylene carbonate chains at the cathode. This hydrogen combines with lithium or oxygen. This means there are many sources of hydrogen emissions within the cell. Free hydrogen is highly flammable and reactive.

[0008] Furthermore, electrochemical oxidation of the PF 6 - Anions occur: The solvents or the trace moisture in the electrolyte serve as a proton source for H abstraction. This means that the instability of the PF 6 -anions is the biggest problem in terms of cell lifespan. PF6−→−ePF6+→PF5+F+→H−abst.HF

[0009] The main disadvantage is that the LiPF 6 The SEI formed leads to a higher impedance. It is assumed that HF, which is a hydrolysis product of LiPF 6 caused by traces of moisture in the electrolyte solvents, with the main components of SEI, namely alkyl carbonate or Li 2 CO 3 , reacts and forms the high-resistance LiF compared to other lithium salts. This leads to a higher internal resistance in the cell.

[0010] Even at room temperature, LiPF produces 6 PF 5-Gas. The production of the gaseous product PF 5 drives the equilibrium to the right, and this process is favored by higher temperatures. In the presence of non-aqueous solvents, the strong Lewis acid PF 5 to trigger a series of reactions, such as ring-opening polymerization or the cleavage of ether bonds in ethylene carbonate. LiPF 6 (s) ⇌ LiF(s) + PF 5 (G)

[0011] On the other hand, the PF bond is quite labile to hydrolysis even by traces of moisture in non-aqueous solvents, producing a range of corrosive products. In short, the electrolyte, in reaction with moisture and at temperatures above 60°C, can release many corrosive gases such as HF, PF 5 and CO 2 generate. LiPF 6 (sol.) + H 2 O ⇌ LiF(s) + 2HF (sol.) + POF 3 (Sol.) PF 5(sol.) + H 2 O ⇌ 2HF (sol.) + POF 3 (sun.)

[0012] A fourth issue concerns the generation of carbon monoxide and hydrocarbons during the formation of SEI and CEI: It is important to have a good solid electrolyte interface (SEI) on the anode and a good cathode-electrolyte interface (CEI) on the cathode. The protective SEI and CEI layers prevent the deterioration of the graphite in the anode and the electrolyte on the cathode. SEI is formed by the reduction process of the electrolyte on the anode. CEI is formed by the oxidation of the electrolyte on the cathode. SEI and CEI are essentially reduced and oxidized byproducts. Unfortunately, both SEI and CEI production generate large amounts of gases. These gases are primarily carbon dioxide and hydrocarbons. These gases are collected in a gas pocket and disposed of after the cell is finally sealed. SEI and CEI is a slow process that takes up to seven weeks.This means that gases are always produced inside the cell after formation. These gases accumulate inside the cell and cannot escape.

[0013] A fifth problem concerns particles detached from the electrode, which can move freely inside the cell and cause a short circuit. Electrodes have a coating of active material. The active materials are bonded to the substrate by a binder. As the binder deteriorates over time and through chemical reactions, the bond strength often decreases. This means that some of the active particles can detach and be removed from the anode or cathode surface. The cohesion between the active materials also weakens over time, as the electrode swells during charging and compresses again during discharging. This means that active material falls into the cell and moves freely in the electrolyte. There is no way to contain these materials.

[0014] EP 1 926 162 A1 discloses a temperature-resistant lithium-ion battery cell. The lithium-ion battery is provided with a cathode comprising a cathode layer with a first cathode material and a first electrolyte containing an electrolyte solution in its carrier medium. The lithium-ion battery is further provided with a gas-absorbing reinforcing cathode layer comprising a second cathode material with lower thermal stability than the first cathode material and a polymer cathode layer capable of enclosing the gas generated by the second cathode material.

[0015] The object of the invention is to provide a lithium-ion battery cell and a method for producing such a battery cell, in which a gas formed in the interior of the cell housing during production or operation can be removed or eliminated in a simple manner compared to the prior art.

[0016] The object is solved by the features of claim 1 or 10. Preferred developments of the invention are disclosed in the subclaims.

[0017] The invention is based on a lithium-ion battery cell in whose cell housing an electrode / separator arrangement is arranged. During manufacture and / or operation of the battery cell, gas formation occurs in the cell housing, for example O 2 -, H 2 -, HF-, CO- and / or CO 2-containing gas. According to the characterizing part of claim 1, at least one reactive element, preferably made of lithium, is arranged inside the cell housing to remove gas. This reactive element forms an ionic bond with the gas formed, i.e., reacts in particular to form lithium salts. Alternatively and / or additionally, at least one adsorption element, preferably made of activated carbon, can be arranged inside the cell housing to remove gas formed, with which the gas can be adsorbed inside the cell housing.

[0018] The electrode / separator arrangement can be a stack in which the electrodes, i.e., anodes and cathodes, are stacked one above the other as individual sheets in the stacking direction, with separators interposed between them. Each of the electrodes consists of a substrate film coated on both sides with active material.

[0019] A core of the invention is to entrap freely flowing gases such as oxygen, hydrogen, fluoride, carbon dioxide, water vapor, and hydrocarbons within the cell using a reactive medium. This prevents these gases from moving freely within the cell, even when they are generated, during cell operation. This is achieved using various methods: The first method involves coating the surface of the last anode electrode (referred to as the stacked-end anode), which is not facing the cathode, with lithium. Since this surface of the anode does not contribute to energy generation, it is not relevant from an energy perspective. This surface can be coated with lithium. Lithium is highly reactive and can therefore entrap gases and form lithium salts. For example, lithium reacts with oxygen to form lithium oxide, lithium reacts with hydrogen to form lithium hydride, and lithium reacts with moisture to form lithium hydroxide.Lithium with fluoride forms lithium fluoride, and lithium with carbon dioxide forms lithium carbonate. These salts are ionically bonded, and therefore gases are strongly attracted to lithium. This means that the lithium coating here does not contribute to energy generation, but rather serves as a reactive medium for the formation of ionic bonds with gases. Normally, a gas pocket can only contain gases generated during the formation / aging process. This lithium coating confines gases throughout cell operation.

[0020] This is achieved by activating the stacked-end anode with an external lithium foil, which serves as the cathode and is connected by an electrolyte-filled bridge. If the lithium coating is applied before the formation process, the gases generated during the formation process may react with the lithium coating and consume most of the lithium coating. The surface of the anode to be coated with lithium is provided with an additional binder, leaving virtually no porosity. Therefore, the lithium emerging from the lithium source during charging will not intercalate in the graphite. Another option is to coat the anode surface with an additional binder layer, making it less porous and thus eliminating the need for a lithium coating.

[0021] Once the lithium coating is applied, the electrolyte bridge between the cell and the external lithium source is removed. The cell is sealed and then put into operation. All gases generated thereafter react with the lithium coating (in the form of a lithium plating) and are trapped by the lithium to form an ionic compound. The invention relates not only to the lithium coating but also to its formation inside the cell.

[0022] Each of the two stack-end anodes preferably has its own separate current collector, or cell collector, used for the lithium coating. The lithium coating is formed on the outer surface of the anode, which does not face the cathode, as it has virtually no porosity. The inner surface of the stack, which faces the cathode, has porosity; there, lithium will intercalate into the graphite, causing pre-lithiation of the anode surface and imparting high capacity to the anode, since the lithium is located inside the anode surface facing the cathode.

[0023] It is also possible that once a lithium coating has formed on the outer surface of the first and last anodes, the charging via an external lithium source bypasses other anodes and causes prelithiation of the other anode surfaces. In this way, all anode surfaces are prelithiated while the outermost anode surface receives a lithium coating.

[0024] According to a second option for generating the lithium coating, a lithium film is applied on the inner side of the housing opposite the anode. This coating is made within the housing in an inert atmosphere. Here, it is not necessary to transfer lithium to the anode surface. The lithium coating is generated inside the housing and then covered with an insulator. The insulator is gas-permeable so that gases can penetrate into the insulator and then react with the lithium to produce an ionic compound.

[0025] A third option is to coat the surface with activated carbon instead of lithium. Activated carbon has a larger surface area and adsorbs gases in its pores. Due to its high microporosity, one gram of activated carbon has a surface area of ​​more than 3,000 m². 2 This means that the anode surface (not facing the cathode) is coated with activated carbon instead of graphite. Activated carbon can adsorb gases, moisture, and even metallic contaminants. The activated carbon coating can be up to 1 mm thick and is sprayed onto the anode surface (not facing the cathode) after another surface (with a graphite coating and facing the cathode) has been calendered. Lithium traps gases by forming an ionic compound. Activated carbon adsorbs gases by trapping them in pores and holding them in place through a weak van der Waals bond.

[0026] A fourth option involves coating the interior of the housing with activated carbon in the form of activated carbon cloth or insulating material coated with activated carbon. Activated carbon can adsorb gases in its pores and does not form an ionic compound like lithium.

[0027] Both lithium coatings on the anode or the housing can be used simultaneously. This means that the outer anode surface of the first and last anodes can be coated with lithium, and the inside of the housing can be coated with lithium.

[0028] The option of using activated carbon on the anode surface or in the housing can also be implemented simultaneously or independently.

[0029] The key differences between the invention and the prior art are summarized as follows: In a first option, the upper and lower anodes have additional current collectors. The other anode current collectors are welded together. There is a second cell casing (i.e., the lithium donor) with a lithium source, which can be a lithium foil or a conventional active cathode material such as NMC, LFP, LMO, etc. with intercalated lithium. An electrolyte bridge is located between the two cell casings. The lithium ions migrate from the lithium donor with the lithium source to the battery cell with the stacks and are deposited in the anode surface. The top side of the upper anode (not facing the cathode) and the bottom side of the lower cathode (not facing the cathode) have virtually no porosity due to the high binder content. A lithium coating forms here.This lithium plating serves as a medium for the confinement of gases inside the cell. This means that the lithium coating is intentionally created to confine the gas. All other anode surfaces have sufficient porosity so that the lithium is intercalated into the graphite, forming a pre-lithiation. After the lithium coating and pre-lithiation have been created, the cell casing is sealed. The core idea of ​​the invention is the intentional creation of a lithium layer. Pre-lithiation is optional and of additional benefit. A second option eliminates the need to charge the cell with a lithium source. Here, an activated carbon coating is applied to the anode surfaces (not the cathode). This means that the anode surfaces, which do not contribute any energy, can now contribute to the confinement of gases and other contaminants.It's also possible to apply a lithium or activated carbon coating inside the cell casing. This coating is then covered with an insulating polymer that is permeable to gases. This allows gases to be trapped without affecting the anodes in the electrode / separator stack. The polymer membrane covering the lithium or activated carbon coating can be made of a polyurethane- or silicone-based material. They should have small pores to allow gases to penetrate. They also serve as an insulating material. Because they are compressible, they also act as a pressure cushion.

[0030] The advantages of the invention are described below: Thus, freely flowing gases within the lithium-ion cell during operation can either be captured as an ionic compound with lithium or adsorbed in the pores of the activated carbon. Thereby, the ion mobility is improved. The gas is enclosed so that the internal pressure does not increase. There is a lower risk of cell venting. The inclusion of oxygen reduces the risk of thermal runaway. By the inclusion of hydrogen and fluoride, the formation of strongly acidic hydrofluoric acid gas (HF) is reduced. This reduces the risk of seal failure and thus the risk of cell venting. By the absorption of moisture, the formation of lithium hydroxide is reduced. Therefore, the capacity of the cell does not decrease as quickly.Carbon monoxide and hydrocarbons produced during the formation of a new SEI (after the dissolution of the old SEI) are trapped and prevent the formation of an irreversible lithium carbonate salt. Metallic impurities due to delamination and flash are trapped by activated carbon. Providing the lithium layer also aids in the pre-lithiation of additional anode surfaces. This will increase the cell's capacity. Constant gas evolution occurs within the cell due to the reaction of cell components such as the binder, separator, and active materials with the electrolyte. This is one of the reasons for the cell's increased internal resistance. The containment of these gases can delay cell aging. It is not necessary to limit the moisture content of the cell components to a very strict level. This contributes to extending the shelf life of the cell components.The drying room conditions required for cell production can be relaxed.

[0031] Embodiments of the invention are described below with reference to the attached figures.

[0032] They show: Fig. 1 to 12 are different representations illustrating the structure and functioning of the battery cell according to the invention.

[0033] In the Fig. 1, a finished battery cell is indicated to the extent necessary for understanding the invention. The battery cell has a cell housing 1, indicated by dash-dotted lines, in which an electrode / separator stack is arranged. The electrode / separator stack has anodes A, cathodes K and separators S arranged between them, stacked one above the other in the stacking direction. Each of the electrodes A, K consists of a substrate film 5 coated on both sides with active material 7. In the case of the cathode K, the active material 7 comprises a metal oxide, for example made of nickel, manganese and cobalt, while in the case of the anode A, the active material 7 consists of graphite. The substrate films 5 of the electrodes A, K are each extended laterally outwards with anode conductor lugs 9 and cathode conductor lugs 11. The conductor lugs 9, 11 are each connected (as indicated by dashed lines) to an anode-side cell conductor 13 and to a cathode-side cell conductor 15.The electrode / separator stack terminates at its upper and lower stack ends with a stack-end anode A. The outer (hereinafter "stack-outer") active material 7 on the side of the respective stack-end anode A facing away from the adjacent cathode is not assigned a corresponding cathode K as a counterpart. The stack-outer active material 7 of the two stack-end anodes A therefore does not contribute to the battery capacity. Rather, it is functionless and merely increases the component weight of the battery cell. The cell housing 1 is also filled with a liquid electrolyte E, which wets the electrodes A, K and the separators S.

[0034] A core of the invention is that the stack-outer active material 7 of the respective stack-end anode A forms a carrier for a lithium layer 17. The lithium layer 17 acts as a reactive element that forms an ionic compound with the gas formed during cell production and / or during cell operation, i.e., reacts in particular to form lithium salts.

[0035] The following is based on the Fig. 2 describes a process step for lithium layer formation, which takes place during cell production, namely after the formation / aging process. This means that all gas formed during the formation / aging process has already been removed. Accordingly, each of the two stack-end anodes A is integrated into a charging circuit LK with an external lithium donor 18 outside the cell housing. The lithium donor 18 is constructed like a battery cell, specifically with a cell housing 20 filled with electrolyte E, in which a lithium source 19 is arranged, for example an element made of lithium metal or of NMC, LFP, LMO. The lithium source 19 is led to the outside of the housing via a connection part 24 and is electrically connected to a charging device 23. The interior of the cell housing 20 of the lithium donor 18 is in flow connection with the interior of the cell housing 1 of the battery cell via an electrolyte bridge 21.In addition, the charger 23 is electrically conductively connected to the anode-side discharge lug 9 of the respective stack end anode A.

[0036] In preparation for the lithium layer formation, the surface of the stack-outer active material 7 of the respective stack-end anode A is coated with a binder layer 22, as described in the Fig. 2. This ensures that during the lithium layer formation the lithium ions do not enter the pores 8 ( Fig. 5) of the active material 7, but rather the formation of the lithium layer 17 on the active material surface is ensured. Alternatively, the active material 7 of the stacked-end anode can also have a higher binder content compared to the other anode active materials 7 in order to reduce the active material porosity.

[0037] In the lithium layer formation process step, the charger 23 performs a charging process. During the charging process, the lithium source 19 is positively charged, while the stack-end anode A is negatively charged. In this way, lithium ions move from the lithium source 19 via the electrolyte bridge 21 into the battery cell housing 1 toward the stack-end anode A, where they are deposited to form the lithium layer 17.

[0038] The charging process performed with each of the stack end anodes A can also be repeated with the middle anode A of the electrode / separator stack 3, as shown in the Fig. 3. In this way, pre-lithiation of the middle anode A is achieved.

[0039] The embodiment of the Fig. 4 to 7 relates to a process arrangement with the aid of which a lithium layer formation analogous to the Fig. 2 and Fig. 3 is feasible. Therefore, reference is made to the description of these figures. The process arrangement has Fig. 4 next to the battery cell the lithium dispenser 18. In contrast to the Fig. 2 is in the Fig. 7, a separate charging circuit LK is provided for each stacked end anode A of the battery cell. In addition, each of the stacked end anodes A has its own cell conductor 29. Overall, the battery cell is therefore designed with three anode-side cell conductors 13, 29. The middle cell conductor 13 is assigned to the two middle anodes A. The cell housing 20 of the lithium dispenser 18 is in the Fig. 4 is fluidically connected to the cell housing 1 of the battery cell via two electrolyte bridges 21, which serve to transfer lithium ions.

[0040] In the Fig. Figure 5 shows one of the stacked-end anodes A in isolation. Accordingly, the outermost (i.e., the upper) active material 7 of the stacked-end anode A has virtually no porosity due to the high binder content. Since there is no porosity there, the lithium is deposited as a lithium coating on the upper side of the upper stacked-end anode A or on the underside of the lower stacked-end anode A. The outermost active material 7 of the two stacked-end anodes A has a binder of more than 15% CMC and more than 10% SBR. This is then additionally (optionally) coated with PTFE or PVDF to close all pores 8. The density of the coating is estimated at approximately 1.6 g / cm 2 compressed.

[0041] The stack interior (that is, in the Fig. 5 the lower) active material 7 of the respective stack end anode A is formed like any other anode surface with about 2 to 3% SBR and 3 to 4% CMC as a binder, so that the stack inner active material 7 is interspersed with pores 8 which provide good porosity.

[0042] In the Fig. 6, the charging process required for the formation of the lithium layer has begun. Accordingly, the charger 23 applies a positive charge to the lithium source 19, while the two stack-end anodes A are applied with a negative charge. In this way, lithium ions move from the lithium source 19 via the electrolyte bridges 21 toward the stack-end anodes A, where they are deposited on the outer active material 7 of the respective stack-end anode A, forming the lithium layer 17. The inner active material 7 of the two stack-end anodes A undergoes pre-lithiation, as the lithium is incorporated into the graphite through the pores 8 in the inner active material 7 of the stack.

[0043] The charging process performed with each of the two stack end anodes A is repeated with the two middle anodes A of the electrode / separator stack 3, as shown in the Fig. 7 is indicated. In the Fig. 7, the middle anode-side cell collector 13 is integrated into a charging circuit LK together with the charger 23 and the lithium donor 18. In this way, pre-lithiation of the active material 7 occurs at the two middle anodes A.

[0044] After completion of the lithium layer formation ( Fig. 6) and the pre-lithiation of the middle anodes A ( Fig. 7) the two electrolyte bridges 21 and the lithium dispenser 18 are removed from the battery cell and the battery cell is sealed as described in the Fig. 8 is indicated.

[0045] Accordingly, the electrolyte bridges 21 are cut off from the cell housing 1 of the battery cell at an interface 31, while a sealing seam 33 is formed as a seal at the edge of the cell housing 1, for example.

[0046] In a further process step ( Fig. 9), the three anode-side cell conductors 13, 29 are combined (e.g., by welding) to form a common anode cell conductor 35. The common anode cell conductor 35 and the cathode cell conductor 15 can then be connected in a charge / discharge circuit K.

[0047] In the Fig. 10a and Fig. 10b shows a further embodiment in which the lithium layer 17 acting as a reactive element no longer directly covers the stacked end anodes A, but rather is formed on the inside of a housing wall 16 of the cell housing 1. The lithium layer 17 has, for example, a layer thickness of 50µm and is according to the Fig. 10a or Fig. 10b is coated with a gas-permeable insulating layer 25, such as a polyurethane membrane. In this way, gas can move through the insulating layer 25 and form an ionic bond with the lithium layer 17, i.e., react with the lithium layer 17, in particular, forming lithium salts. The insulating layer 25 acts in the Fig. 10a additionally as a compression pad which is in contact with the electrode / separator stack with an elastically yielding force.

[0048] In the Fig. 11a and Fig. 11b shows a further embodiment in which, instead of the lithium layer 17 acting as a reactive element, an activated carbon layer 27 is arranged on the inside of the housing wall 16 of the cell housing 1. The activated carbon layer 27 can, for example, have a layer thickness of 0.5 to 1 mm and can also be designed, for example, as an activated carbon fabric or as an insulating polymer coated with activated carbon. The activated carbon layer 27 acts as an adsorption element with which the gas formed in the cell housing interior can be adsorbed. The activated carbon layer 27 is according to the Fig. 11a or Fig. 11b is also coated with a gas-permeable insulating layer 25, such as a polyurethane membrane. This allows gas to move through the insulating layer 25.

[0049] In the Fig. 12 is in a view corresponding to the Fig. 1 shows another embodiment. In contrast to Fig. 1 is in the Fig.12, the stack-outer active material 7 (usually graphite) of the respective stack-end electrode A is replaced by the activated carbon layer 27. The activated carbon layer 17 on the respective stack-end anode A is produced by dry coating and subsequent calendering. The detailed steps are as follows: First, the stack-inner active material 7 of the respective stack-end anode A is produced using the conventional method. Then, the stack-outer side of the substrate film 5 of the respective stack-end anode A is coated with activated carbon using a spray process or another dry method. The entire stack-end anode A is calendered again. The calendering force for pressing the activated carbon is much lower in order to create a high porosity of the activated carbon. The calendering force only ensures good adhesion of the activated carbon and binder to the substrate film 5 (e.g., the copper substrate). List of reference symbols 1 cell housing 5 Substrate film 7 Active material 8 pores 9 anode-side arrester lug 11 cathode-side arrester lug 13 anode-side cell arrester 15 cathode-side cell arrester 16 Housing wall 17 Lithium layer 18 lithium dispensers 19 Lithium source 21 Electrolyte bridge 22 Binder course 23 Charger 24 connecting part 25 gas-permeable insulation layer 27 Activated carbon layer 29 outer cell conductor 31 interfaces 33 Seal 35 common cell arrester LK charging circuit A Anode K cathode E Electrolyte 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] EP 1 926 162 A1

[0014]

Claims

[1] Lithium-ion battery cell, in the cell housing (1) of which an electrode / separator arrangement is arranged, wherein during the manufacture and / or operation of the battery cell in the cell housing (1) a gas formation occurs, such as O2-, H2-, HF-, CO- and / or CO2-containing gas, characterized by that in order to eliminate gas formed in the cell housing interior at least one reactive element (17) made preferably of lithium is arranged, which forms an ionic compound with the gas formed, that is to say reacts in particular with the formation of lithium salts, and / or that in order to eliminate gas formed in the cell housing interior at least one adsorption element (27) made preferably of activated carbon is arranged, which adsorbs the gas. [2] Lithium-ion battery cell according to claim 1, characterized bythat the electrode / separator arrangement is a stack in which the electrodes, i.e. anodes (A) and cathodes (K), are stacked one above the other in the stacking direction with separators (S) interposed and are wetted with a liquid electrolyte (E), and that in particular at least one of the two stack end electrodes, in particular stack end anodes (A), has a lithium layer as a reactive element (17) or an activated carbon layer (27) as an adsorption element on its outer side. [3] Lithium-ion battery cell according to claim 2, characterized bythat the electrodes, i.e. anodes (A) and cathodes (K), each consist of a substrate film (5) which is coated on both sides with active material (7), and that in particular the active material (7) on the stack-outer side of the stack-end electrode (A) is coated with the lithium layer (17), or that the active material (7) on the stack-outer side of the stack-end anode (A) is the activated carbon layer (27) instead of graphite. [4] Lithium-ion battery cell according to one of the preceding claims, characterized bythat the lithium layer formation takes place during cell production after a formation / aging process, and that in particular in the lithium layer formation the stack end anode (A) is integrated in a charging circuit (LK) in which an external lithium source (19) outside the cell housing is electrically conductively connected to the stack end anode (A) via an electrolyte bridge (21), and is electrically conductively connected to the stack end anode (A) via a charging device (23). [5] Lithium-ion battery cell according to claim 4, characterized bythat in a charging process the charger (23) applies a positive charge to the lithium source (19) and a negative charge to the stack end anode (A) so that lithium ions move from the lithium source (19) via the electrolyte bridge (21) in the direction of the stack end anode (1) and are deposited there to form the lithium layer (17), and that in particular after completion of the lithium layer formation the electrolyte bridge (21) and the lithium source (19) are removable from the battery cell and the battery cell is sealed in the further course of the process. [6] Lithium-ion battery cell according to claim 5, characterized bythat the active material (7), i.e. graphite, on the side of the stack end anode (A) facing away from the adjacent cathode (K) - in comparison to the other anode active materials (7) in the electrode / separator stack (3) - has an increased binder content in order to reduce the active material porosity, so that during the lithium layer formation the lithium ions do not become embedded in the pores (8) of the active material (7), but rather the lithium layer (17) forms on the active material surface, or that before the lithium layer formation is carried out the active material surface is coated with a binder layer (22) in order to ensure the formation of the lithium layer (17) on the active material surface. [7] Lithium-ion battery cell according to claim 5 or 6, characterized bythat the charging process carried out with the stack end anode (A) is repeatable with the other anodes (A) in the electrode / separator stack (3) in order to achieve pre-lithiation of these anodes (A). [8] Lithium-ion battery cell according to claim 1, characterized by that the lithium layer (17) acting as a reactive element is formed on the inside of a housing wall (16) of the cell housing (1), and that the lithium layer (17) is coated with a gas-permeable insulating layer (25) so that gas moves through the insulating layer (25) and forms an ionic bond with the lithium layer (17). [9] Lithium-ion battery cell according to claim 1, characterized by that the activated carbon layer (27) acting as an adsorption element is formed on the inside of a housing wall (16) of the cell housing (1), for example as an activated carbon fabric or as an insulating polymer coated with activated carbon. [10] A method for producing a lithium-ion battery cell according to one of the preceding claims, in the cell housing (1) of which an electrode / separator arrangement is arranged, wherein during the manufacture and / or operation of the battery cell in the cell housing (1) a gas formation takes place, such as O2-, H2-, HF-, CO- and / or CO2-containing gas, characterized by that in order to eliminate gas formed in the cell housing interior at least one reactive element (17) made preferably of lithium is arranged, which forms an ionic compound with the gas formed, that is to say reacts in particular with the formation of lithium salts, and / or that in order to eliminate gas formed in the cell housing interior at least one adsorption element (27) made preferably of activated carbon is arranged, which adsorbs the gas.

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