DE102021111629A1 - Electrical assembly of battery cells and method for producing the same - Google Patents

Abstract

A manufacturing method for an electrical assembly (1) and an electrical assembly (1) of battery cells is proposed. The electrical assembly comprises a first battery cell (2) with a first cell casing (3), a second battery cell (2) with a second cell casing (3), and a thermally insulating glass casing (4) made of solid glass between the first battery cell (2) and the second battery cell (2).

Description

The present invention relates to an electrical assembly of battery cells and a manufacturing method for an electrical assembly of battery cells. In particular, the present invention relates to preventing battery cells from heating up within an electrical network of battery cells due to thermally “runaway” battery cells that have an excessive temperature.

The thermal management of an electrical energy store is one of the main pillars of an electrical energy store. The thermal management influences the service life, performance and operational reliability of the energy store. The energy storage and the battery cells contained in it as the smallest units can be cooled or heated as required. Various media and technologies are used for this. A conflict of objectives in thermal management is that, on the one hand, the individual battery cell should be well connected to the cooling/heating system, and on the other hand, in the event of a thermal event in a battery cell, the thermal energy must be dissipated in a targeted manner and the neighboring cells must be protected against unwanted heat input.

In principle, there are two ways of delaying or even stopping the excessive energy transfer to individual neighboring cells in the event of a thermal event in a battery cell. For example, the heat is distributed as evenly as possible to the neighboring cells and adjacent thermal storage (thermal masses). It should be noted here that the neighboring cells do not experience a thermal anomaly (thermal event) themselves, or only do so with a very long delay. Alternatively, the heat is retained in the affected battery cell, for which purpose neighboring battery cells must be thermally insulated from the affected battery cell and additionally connected to suitable thermal masses for heat dissipation. In the prior art, thermal insulation is achieved, for example, using silicone, mica, mica or other insulating materials.

GB 256,400 discloses a Leclanche or similar type battery cell having a glass can in which the cell chemistry is contained. A lid of the glass cup can also be made of glass yourself.

Insulating materials used in the prior art are usually not dimensionally stable, since the melting point can only be increased upwards to a limited extent and the thermal capacity is limited.

Proceeding from the aforementioned prior art, it is an object of the present invention to improve the thermal management of an assembly of electrical energy stores or battery cells.

According to the invention, an electrical combination of battery cells is proposed, which can also be designed as an accumulator or battery. In particular, the electrical assembly of battery cells is provided for use as a traction battery of an electrically drivable means of transportation. It includes a first battery cell, which has a first cell casing. The cell coat is designed to absorb the cell chemistry, i.e. the electrolyte solutions and solids. The first battery cell can be designed, for example, as a standard battery cell, such as is currently manufactured for use in electrically driven means of transportation, in particular passenger cars. Such battery cells can have an essentially cylindrical body. In this case, the battery cells are referred to as round cells or cylindrical battery cells. The electrical assembly of battery cells also includes a second battery cell with a second cell casing. What was said in connection with the first battery cell applies to the second battery cell in a corresponding manner. In particular, both battery cells can be identical in terms of their specification. In addition, a thermally insulating glass jacket made of solid glass is provided between the first battery cell and the second battery cell. In other words, the glass jacket is located between the first cell jacket and the second cell jacket. Glass has the advantage of a very high melting point and a less pronounced exothermic potential. The cell jacket is to be understood in particular as the cylindrical jacket surface of the respective battery cell. The longitudinal axes of the respective battery cell can lie parallel to one another, so that the end faces of the individual battery cells (first battery cell and second battery cell) lie essentially in an identical plane. In this way, the glass jacket can thermally insulate the first battery cell from the second battery cell (and vice versa), while the end face of the first battery cell and the second battery cell can be thermally coupled to a heating/cooling system without the glass jacket supplying heat or prevents heat dissipation via the end faces.

The dependent claims show preferred developments of the invention.

The glass jacket can be made in one piece or in several pieces. The first battery cell, for example, a first glass jacket and the second battery cell, a second, not integral with the first glass cladding have manufactured second glass cladding. Each glass jacket preferably has a recess, within which at least one battery cell of the electrical assembly of battery cells is arranged. This ensures that a continuous battery cell does not give off its excess heat to other battery cells, but primarily to the heating/cooling system and neighboring cells are thermally protected. The end faces of the first battery cell and the second battery cell can be thermally connected to the heating/cooling system by a cover and/or a base. The cover and the base, together with the glass jacket, can define a volume within which the battery cell and in particular all of the parts belonging to it are contained. This optionally does not include, at least in part, electrical connection lines to be assigned to the battery cell, which allow external electrical contacting of the first battery cell and the second battery cell (optionally with one another) through the cover and/or through the base.

The glass jacket can be a one-piece glass jacket that surrounds the first battery cell and/or the second battery cell. In particular, the glass casing can be a structure made of solid glass, which has two or more recesses, one of the battery cells being arranged in each of the recesses. Such a glass jacket could also be referred to as a “monoblock”, which has cylindrical or other types of bores, the bore axes of which can lie essentially parallel to one another. In this way, the individual battery cells are also mechanically/spatially fixed to one another and in relation to their surroundings by means of the glass casing.

The glass jacket can be prefabricated. For example, the glass jacket can first be cast and/or pressed and only in its final form are the first battery cell and the second battery cell inserted into it. This does not preclude the glass jacket from being able to have a plurality of glass jacket bodies or glass jacket segments, which together represent the glass jacket of a single battery cell or the glass jacket of a plurality of battery cells. For example, tubes (e.g. hollow cylinders), half tubes, quarter tubes or segments of other shapes can be assembled into a respective glass cylinder. This does not rule out the possibility of using a casting compound, in particular glass, after assembly, in order to improve the insulation again and/or to connect the glass jacket bodies to one another or to spatially fix them. The first battery cell and the second battery cell may be inserted into the glass envelopes prior to the aforementioned potting step. Particularly in the event that the first battery cell and the second battery cell are already inserted into the glass casing before they are cast, the casting compound can also fix the respective battery cell within its (respective) glass casing, which means that additional anchoring can be omitted.

A “glass jacket” within the meaning of the present invention is to be understood as a solid structure for isolating two electrical battery cells of the electrical assembly from one another, without necessarily implying a specific spatial structure. Rather, as a glass jacket in the sense of the present invention, the suitability of the feature should be understood to use the thermally insulating property of solid glass to prevent heat transfer from a first battery cell to a second battery cell and at the same time a thermal coupling of the first battery cell and the second battery cell to a enable heating/cooling system. In particular, therefore, there is no glass jacket at that position of the first battery cell and the second battery cell at which the first battery cell or the second battery cell is not directly adjacent to any other battery cell (“front face”).

The glass jacket can be made of glass. In other words, the glass jacket can essentially have no further material apart from glass. This does not preclude the glass jacket from being able to have a coating, in particular a metallic coating, to increase its thermal insulation capacity. The coating can be vapor-deposited, for example. In particular, it can have a glossy surface in order to reflect radiant heat or thermal radiation. The presence of a first glass jacket around the first battery cell or the second battery cell does not rule out the presence of a second glass jacket around the battery cell in question. In other words, a first glass jacket can be thermally insulated from the environment or from other battery cells by a second glass jacket. An air gap also benefits the insulation, which can improve thermal insulation due to the heat transfer properties between glass and air. Another gas that contributes to the thermal insulation can also be provided in the aforementioned gap.

The glass jacket can have a stabilizing structure in the manner of a wire mesh or a plastic inlay. Foreign bodies of this kind in the glass can mechanically stabilize the glass jacket or alleviate the consequences of mechanical overload, as is the case with safety glass for example in automobile construction.

The use of colored glass for the glass jacket is also an option, for example in order to be able to use particularly inexpensive recycled glass or to further reduce thermal radiation. In other words, the glass provides an optical filter that changes the appearance of visible light passing through it.

The cell casing of the first battery cell and the cell casing of the second battery cell can each comprise plastic and/or aluminum and/or steel and/or composite materials, comprising the aforementioned materials. While plastic is cheap and chemically resistant, metallic materials can bring about an external homogenization of the heat dissipation of the first battery cell or the second battery cell in order to prevent thermal overstressing of an immediately adjacent battery cell.

The glass jacket can have a hollow-cylindrical shape, a hollow-prismatic shape (cylinder with a pentagonal or hexagonal cross-section) and/or a rotationally symmetrical shape and/or a square-tubular shape. In this case, the inner surface of the glass jacket and/or the outer surface of the glass jacket can be canted or round (in particular cylindrical) in shape. While a hexagonal external cross-section of the glass jacket enables a particularly dense packing of a large number of battery cells encased according to the invention, a hollow-cylindrical shape of the glass jackets can have advantages in the subsequent encapsulation of the battery cells encased according to the invention.

The glass jacket can have a substantially constant cross section, for example as an extruded and/or continuously cast profile. In other words, the cross-sectional area of the glass jacket does not vary between its opposing end faces or between the cover and the base around the battery cell. This allows a particularly dense packing and a cheap production.

Electrical contacting of the first battery cell and the second battery cell can take place in particular through a metallic cover and/or a metallic base. For example, a first pole of the battery cell can be routed to the outside via the metal cover, while a second pole is routed to the outside electrically via the metal base. Of course, the cover and/or the base can also have a number of segments which are electrically insulated from one another, so that the base or the cover can have both electrical connections.

When “glass” is mentioned in the context of the present disclosure, this means in particular a glass body which, for example, has borosilicate glass or consists of such. This is particularly resistant to heat and temperature changes, has a low coefficient of linear thermal expansion and high mechanical strength. Alternatively or additionally, tempered glass can also be used as the material for the glass jacket.

Spacers may be provided between the first battery cell and its glass envelope to provide an air gap and additional air gap insulation as is known from thermos flasks. The same applies to the second battery cell and its glass jacket or each additional battery cell of the electrical network.

In particular, shock absorbers can be provided on the outside of the glass jacket in order to mechanically decouple the surrounding and supporting structures and to prevent damage to the glass jackets. For example, the glass jackets can be used in a housing to represent the electrical network. The glass jackets can be cast and/or foamed into the housing.

According to a second aspect of the present invention, a method for producing an electrical compound according to the above statements is proposed. The method initially includes inserting a first battery cell, which has the cell chemistry and a cell casing and, if appropriate, electrical connections, into a first thermally insulating glass casing made of solid glass. The same procedure is used with a second battery cell and a second thermally insulating glass jacket. The second thermally insulating glass envelope may be identical to the first thermally insulating glass envelope or even one and the same. In the latter case, however, it has to have a second recess for introducing the second battery cell. In addition, the first battery cell and the second battery cell are electrically connected to one another in order to produce the electrical network. This step can be carried out before the first battery cell is inserted into the first thermally insulating glass jacket and/or before the second battery cell is inserted into the second thermally insulating glass jacket. Alternatively, the first battery cell and the second battery cell can be electrically connected after the first battery cell has been inserted into the first thermally insulating glass jacket and the second battery cell into the second thermally insulating glass jacket. Optionally, the first thermally insulating glass jacket compared to the second thermally insulating glass jacket are fixed by a casting compound. This can be done before inserting the first battery cell into the first thermally insulating glass jacket and before inserting the second battery cell into the second thermally insulating glass jacket. Alternatively, this can be done after the first and second battery cells have been inserted into the respective glass casing. Optionally, the first battery cell can also be encapsulated in the first thermally insulating glass jacket. The same applies to the second battery cell and the second thermally insulating glass jacket.

Further optionally, the first glass jacket can be mechanically connected to the second glass jacket. This can occur as a result of the two glass jackets being cast. Alternatively or additionally, the mechanical connection can take place before the first battery cell is inserted into the first glass casing and the second battery cell is inserted into the second glass casing. Alternatively, the mechanical connection can take place after the first battery cell has been inserted into the first glass casing and the second battery cell has been inserted into the second glass casing.

Before or after the encapsulation, the arrangement comprising the first battery cell and the first glass casing and the second battery cell and the second glass casing can be inserted into a housing of the electrical assembly. Optionally, the glass jackets can also be inserted into the housing beforehand and the first battery cell and the second battery cell can only then be inserted into their respective glass jacket. A substantially closed housing can help with the encapsulation, in that the encapsulation compound is filled into the housing and the glass jackets are mechanically fixed to one another and mechanically within the housing by the encapsulation compound.

The housing can contain positioning aids, e.g. in the manner of a beer crate, through which the glass jackets are mechanically/spatially fixed in the housing (temporarily or makeshift) until a subsequent casting step causes the glass jackets to be finally fixed in the housing. Of course, any other suitable fixation of the glass jackets in the housing is possible. In particular, the housing can have a housing cover which mechanically fixes the glass jackets in the housing.

• 1 eine perspektivische Darstellung eines Ausführungsbeispiels eines elektrischen Verbundes mit im Wesentlichen quaderförmigen Batteriezellen, zwischen welchen jeweils im Wesentlichen quaderförmige Zellmantelsektionen vorgesehen sind;
• 2 eine perspektivische Darstellung eines Ausführungsbeispiels, in welchem im Wesentlichen zylindrische Batteriezellen durch im Wesentlichen hohlzylindrische Glasmäntel thermisch einander gegenüber isoliert und thermisch an ein Heiz-/Kühlsystem angeschlossen sind;
• 3 eine perspektivische Darstellung eines Glasmantels in Form eines Monoblocks mit zylindrischen Bohrungen; und
• 4 ein Flussdiagramm veranschaulichend Schritte eines Ausführungsbeispiels eines erfindungsgemäßen Verfahrens zur Herstellung eines elektrischen Verbundes von Batteriezellen.

Further details, features and advantages of the invention result from the following description and the figures. Show it:

• 1 a perspective view of an exemplary embodiment of an electrical assembly with essentially cuboid battery cells, between which essentially cuboid cell casing sections are provided;
• 2 a perspective view of an embodiment in which essentially cylindrical battery cells are thermally insulated from one another by essentially hollow-cylindrical glass jackets and are thermally connected to a heating/cooling system;
• 3 a perspective view of a glass jacket in the form of a monoblock with cylindrical bores; and
• 4 a flowchart illustrating steps of an exemplary embodiment of a method according to the invention for producing an electrical assembly of battery cells.

1 shows an electrical assembly 1 of battery cells 2, which have a respective cell casing 3 and electrical contacts 9, 10 arranged on an upper end face. Between the electrical contacts 9, 10 respective cell valves (cell vents) 6 are provided. In order to reduce lateral heat propagation in the direction of the arrow P from a defective battery cell to neighboring cells, glass jackets 4 , which are shown proportionately, are arranged between the cell jackets 3 and are configured similarly to a flat pane of glass. Because the glass jackets 4 do not cover the end face of the battery cells 2, the battery cells 2 can dissipate heat upwards and downwards to a heating/cooling system (not shown).

2 shows a perspective view of an electrical assembly 1 of battery cells 2, which have a cell vent 6 on their end face. The upper face has a respective electrical contact 9 and for the sake of clarity is not connected to a heating/cooling system provided on the lower face. The essentially cylindrical battery cells 2 each have a glass jacket 4 made of solid glass. By way of example, a glass jacket is composed of two glass jacket bodies 4a, 4b. Due to the distance between the glass jackets 4, a casting compound can be poured between the glass jackets in order to mechanically fix the glass jackets within the electrical assembly 1 and to thermally insulate the battery cells 2 from one another.

3 shows a glass jacket 4 made in monoblock construction, which has a plurality of recesses 5 in the form of cylindrical through-holes. In a further manufacturing step, battery cells 2 (not shown) can be inserted into the recesses 5, encapsulated and then electrically connected to one another. For example, a front recess 5 has a second glass jacket 41, to which there is a circumferential air gap 8 within the recess 5, which extends over the entire height of the glass jacket 4, in order to further increase the thermal insulation.

4 shows a method illustrating steps of an embodiment of a method according to the invention for producing an electrical assembly of battery cells. In step 100, a first battery cell with a first cell casing is inserted into a thermally insulating glass casing made of solid glass. In principle, the battery cell is already fully functional electrically. In other words, the thermally insulating glass jacket has no effect that defines the cell chemistry and the mechanical components in relation to one another. In step 200, a second battery cell and a second thermally insulating glass jacket are processed in a corresponding manner. In step 300, the first glass cladding is mechanically connected to the second glass cladding. This can include the introduction of a casting compound between the first glass jacket and the second glass jacket, which also results in a mechanical fixation of the two glass jackets with respect to a housing structure surrounding them. Finally, in step 400, the first battery cell is electrically linked to the second battery cell. A housing of the electrical assembly can then be closed and used as a traction battery in an electrically drivable means of transportation.

Reference List

1

electrical network of battery cells

2

battery cell

3

cell coat

4

glass jacket

4a, 4b

glass jacket body

5

recess

6

cell vent

7

floor

8th

air gap

9, 10

electrical connections

11

heating/cooling system

41

another glass coat

100 to 400

process steps

P

Arrow

Claims (13)

Electrical network comprising battery cells - a first battery cell (2) with a first cell casing (3), - A second battery cell (2) with a second cell jacket (3), and - A thermally insulating glass jacket (4) made of solid glass between the first battery cell (2) and the second battery cell (2). Electrical connection according to claim 1 , wherein the glass jacket (4) is arranged between the first cell jacket (3) and the second cell jacket (3). Electrical connection according to claim 1 or 2 , the glass jacket (4) being made in one piece or in several parts and having a recess - which is closed off at the top by a cover which has a high thermal conductivity compared to the glass jacket (4) and/or - which is closed off at the bottom by a base (7). is, which compared to the glass jacket (4) has a high thermal conductivity. Electrical assembly according to one of the preceding claims, wherein the glass casing (4) is a one-piece glass casing which surrounds the first battery cell (2) and/or the second battery cell (2). Electrical assembly according to one of the preceding claims, in which the glass jacket (4) is prefabricated and in particular has a plurality of glass jacket bodies (4a, 4b). Electrical assembly according to one of the preceding claims, in which the glass jacket (4) consists of glass. Electrical assembly according to one of the preceding claims, wherein the glass of the glass jacket (4) has a metallic coating for thermal insulation. Electrical assembly according to one of the preceding claims, wherein the glass jacket (4) has an air gap (8) which is set up to thermally decouple an inner glass jacket and an outer glass jacket (4) from one another. Electrical assembly according to one of the preceding claims, wherein the glass jacket (4) - A hollow cylindrical shape and / or - a rotationally symmetrical shape and/or - Has a tubular shape. Electrical assembly according to one of the preceding claims, in which a cross section of the glass jacket (4) does not vary between opposite end faces. Electrical assembly according to one of the preceding claims, which is set up to allow external electrical contacting of the battery cells (2) through the cover (6) and/or the base (7). Method for producing an electrical assembly of battery cells according to one of the preceding claims, comprising the steps: - Insertion (100) of a first battery cell (2) with a first cell casing (3) in a first thermally insulating glass casing (4) made of solid glass, - Insertion (200) of a second battery cell (2) with a second cell casing (3) in a second thermally insulating glass casing (4) made of solid glass, and - Electrically linking (400) the first battery cell (2) and the second battery cell (2). procedure after claim 12 further comprising: - mechanically connecting (300) the first and the second glass cladding (4).

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