DE102022102620A1 - Cell holder for holding a plurality of battery cells and vehicle battery assembly - Google Patents

Abstract

The present invention relates to a cell holder (1) for holding a plurality of battery cells (7) in a battery module, comprising a holding section (2) made of a first plastic, formed from a plurality of holders (4) arranged next to one another and connected to one another for holding each at least one battery cell (7), and a connecting section (3) which is formed in one piece with the holding section (2) and is made of a second plastic that is different from the first plastic and adjoins the holding section (2) for thermally connecting the cells held in the receptacles (4). Battery cells (7) to a temperature control device (10); it also relates to a vehicle battery arrangement (100) having such a cell holder (1).

Description

technical field

The present invention relates to a cell holder for holding a plurality of battery cells in a battery module and a vehicle battery assembly.

State of the art

It is known to form electrochemical energy stores, such as vehicle batteries, in particular lithium ion batteries, from a large number of individual battery cells. A predetermined number of battery cells are often combined in a battery module, with the vehicle battery often having a plurality of such battery modules which are arranged in a battery housing stacked approximately in a stacking direction. Particularly in the case of battery storage systems that are formed from cylindrical cells, the individual battery cells are often held, positioned and spaced apart from one another by cell holders. In addition to sufficient structural integrity of the battery, battery cells that do not have their own insulation, as is often the case with cylindrical battery cells, for example, can also be electrically insulated from one another.

Cell holders are often made of a plastic. They usually have a complex geometry because they have to accommodate a large number of battery cells.

Electrochemical energy stores, in particular lithium-ion batteries, have a limited operating temperature range. Outside of this range, such battery cells lose their performance, age faster or reach safety-critical states.

For this reason, battery cells are actively temperature-controlled in many applications, particularly in the case of lithium-ion batteries in electric and hybrid vehicles, and are therefore thermally conditioned. This means that they are heated or cooled as required in order to remain within a specified temperature range that is safe and advantageous for the operation and maintenance of the battery cells.

In most electric vehicles, this takes place via a temperature control device through which a liquid temperature control medium, for example cooling water, flows. The battery cells are thermally connected to the temperature control device, so that heat transfer between the battery cells and the temperature control device is possible. Depending on the temperature of the temperature control medium, the battery cells can be actively heated or cooled.

In many cases, the temperature control device has a flat, planar geometry. It is therefore often designed in the form of an essentially flat temperature control plate. The battery cells are usually connected to the temperature control plate using a flexible, thermally conductive mat, the so-called “gap pad”, or using a liquid or pasty, partially hardening material, the so-called “gap filler”. These elements make it possible to compensate for tolerances and surface irregularities and roughness of the battery cells and/or the tempering plate. In addition, a low thermal resistance between the battery cells and the tempering plate can be achieved.

The use of gap fillers is relatively expensive due to the comparatively high material price. In addition, the application process is complex. In the case of gap fillers that do not harden, there is also the risk that parts of the gap filler will migrate as a result of the later effects of temperature and acceleration forces, for example flowing out of the intended position between the battery cells and the temperature control device. In the case of hardening gap fillers, subsequent disassembly of a battery cell module is made more difficult or even impossible, among other things because the battery cells, the cell holder and/or the temperature control device are at least partially glued to one another via the hardened gap filler. Furthermore, when the gap filler is applied, it cannot be ruled out that air bubbles are trapped within the gap filler and/or at the interfaces to the battery cells and/or the temperature control device. Accordingly, gap fillers are not suitable as the sole electrical insulation between the battery cells and the mostly metallic temperature control device, so that an additional insulating layer, e.g. a foil, is required to ensure the electrical insulation of the battery cells from the temperature control device. The film represents a further intermediate layer between the battery cells and the temperature control device. It introduces two further interfaces between the battery cells and the temperature control device.

Gap pads, on the other hand, only have a limited heat transfer capacity due to the contact surface being limited to one level. In addition, the handling and positioning of the gap pads in production are associated with a comparatively high level of effort, since the gap pads to be used are generally flexible and at least partially have sticky surfaces.

Presentation of the invention

Based on the known prior art, it is an object of the present invention to provide an improved cell holder for holding a plurality of battery cells in a battery module, and to provide an improved vehicle battery assembly.

The object is achieved by a cell holder for holding a plurality of battery cells in a battery module having the features of claim 1. Advantageous developments result from the dependent claims, the description and the figures.

Accordingly, a cell holder for holding a plurality of battery cells in a battery module is proposed, comprising a holding section made of a first plastic, formed from a plurality of receptacles arranged next to one another and connected to one another, each for holding at least one battery cell.

The cell holder also includes a connection section, which is formed in one piece with the holding section and is made of a second plastic that is different from the first plastic, and adjoins the holding section, for thermally connecting the battery cells held in the receptacles to a temperature control device.

Due to the fact that the cell holder comprises a connection section, which is formed in one piece with the holding section and is made of a second plastic that is different from the first plastic and adjoins the holding section, for thermally connecting the battery cells held in the receptacles to a temperature control device, the otherwise required provision of a separate gap Fillers and/or a separate gap pad are dispensed with. In other words, the connection section can simulate or provide the thermally conductive function of a gap filler or a gap pad.

Accordingly, when using a cell holder designed in this way, it is possible to simplify the construction of a battery arrangement in comparison to conventional battery arrangements. In particular, the provision of a separate heat transfer element, for example a gap filler or gap pad, can be dispensed with. Even if the use of a gap filler is also planned, its quantity can be significantly reduced compared to conventional battery arrangements. Furthermore, the risk of a non-hardening gap filler penetrating due to running between the battery cells can be reduced by the connection section or—with a correspondingly closed shape of the connection section—can even be completely avoided.

The reduction in the number of parts also results in lower production costs, which, in addition to the elimination of material costs with regard to gap fillers or gap pads, reduces the manufacturing costs of a battery arrangement that includes the cell holder compared to conventional battery arrangements.

Manufacturing complexity and manufacturing costs are also favorably influenced in that the cell holder according to the invention achieves functional integration in a molded part by providing the connection section, so that complex application steps and/or curing processes are eliminated in the manufacture of the battery arrangement.

Furthermore, such a cell holder can provide a comparatively high degree of security against insulation faults due to liquid entering between the battery cells and/or between battery cells and temperature control device, in particular due to the one-piece, essentially closed design of the one-piece multi-component part.

A comparatively good thermal contact between the battery cells and the temperature control device can also be achieved, in particular due to the reduction to a single intermediate layer.

The cell holder can also provide reliable electrical insulation between the battery cells and the temperature control device via the connection section, without additional insulating films or the like being required.

Furthermore, the cell holder can provide protection for battery cells received in the receptacles during transport and storage due to the preferably substantially closed contour on the underside.

In contrast to the use of (partially) hardening gap fillers, when using a cell holder according to the invention there is no direct adhesion between the battery cells and the temperature control device, so that the battery mode can be disassembled without any problems or at least comparatively easily.

In order to be able to achieve secure mechanical retention of the battery cells in the retaining section and at the same time a two-dimensional thermal coupling of the connection section to the battery cells and to the temperature control device, the first plastic can have a greater Shore hardness than the second plastic. The first plastic can therefore be designed to be sufficiently hard and/or dimensionally stable in order to provide mechanical retention of the battery cells, which withstands the mechanical forces during transport and operation of the battery cells in a dimensionally stable manner. The second plastic can be sufficiently soft and deformable be formed, consequently having such a deformability, so that an adaptation of the surface of the connection section to the surface of the battery cells and the surface of the temperature control device and therefore a surface contact with these is possible. In other words, the second plastic or the connection section has a deformability due to its Shore hardness, which allows it to nestle against the surface and contour of the battery cells and those of the temperature control device.

The Shore hardness is preferably measured or indicated in the form of Shore C or Shore D. The Shore hardness degrees preferably relate to values as they are from a method according to a standard, preferably ISO 7619-1 , EN ISO 868 , DIN 53505 or ASTM 2240.

The difference in Shore hardness between the first plastic and the second plastic is preferably at least 5 Shore C degrees of hardness or at least 2 Shore D degrees of hardness, with the second plastic preferably having a Shore C hardness in the range from 9 to 65 Shore C and/or the first plastic has a Shore C hardness greater than or equal to 60 Shore C, and/or preferably the second plastic has a Shore D hardness in the range from 6 to 44 Shore D and/or the first plastic has a Shore D hardness greater than 40 Shore D, preferably greater than 45 Shore C and/or the first plastic has a Shore D hardness in the range from 40 to 95 Shore D.

According to a further preferred embodiment, the cell holder is a two-component injection-molded part, with the holding section preferably being primary formed in a first injection molding step and the connection section being primary formed integrally with the retaining section in a second injection molding step. Alternatively, the connection section can also be primary formed in a first injection molding step and the holding section can be primary formed integrally with the connection section in a second injection molding step.

The receptacles are preferably arranged next to one another in one plane, with the connection section preferably adjoining the holding section in a direction transverse to the plane.

According to a further preferred embodiment, the receptacles of the holding section are designed to receive at least one, preferably precisely one, cylindrical battery cell, prismatic battery cell and/or pouch battery cell.

It has proven to be advantageous if the receptacles of the holding section for holding a battery cell are formed on a side surface of the battery cell in relation to a longitudinal axis of the battery cell.

The connection section is preferably designed to make planar contact with a base of the battery cells. Due to the areal connection, a comparatively large interface with low thermal resistance can be achieved between the battery cell and the connection section and thus a particularly efficient heat transfer.

The connection section can also be designed for areal contacting of a base and a side surface section of the battery cells adjoining the base. With such a structure, an additional increase in the heat transfer from or into the battery cells can be achieved--particularly in comparison to gap pads or fillers.

If the connection section is designed to contact a bottom of the battery cells, the connection section preferably represents a bottom of the receptacles, which are then formed in the manner of a blind hole Plastic is formed and the bottom or the bottom and a lower part of the side wall of the receptacle are formed by the second plastic.

According to a further preferred embodiment, the connection section is essentially plate-shaped.

On a side facing the holding section, the connection section can have a contacting surface for preferably planar thermal contacting of the battery cell and opposite the contacting surface a connection surface for preferably planar thermal contacting of the temperature control device, preferably a temperature control surface of the temperature control device.

In order to be able to provide sufficient heat conduction between the battery cells and the temperature control device and also to be able to achieve sufficient thermal decoupling between the battery cells, the second plastic can preferably have a higher specific thermal conductivity than the first plastic, preferably by at least 0.5 W / (m*K), preferably at least 1 W/(m*K), particularly preferably at least 1.5 W/(m*K), very particularly preferably at least 2 W/(m*K) higher specific thermal conductivity at room temperature and medium humidity.

Here, room temperature is understood to be in particular 20° C., mean atmospheric humidity being in particular 50% atmospheric humidity.

The second plastic preferably has a specific thermal conductivity of at least 0.5 W/(m*K), preferably at least 1 W/(m*K), particularly preferably at least 1.5 W/(m*K), and very particularly preferably at least 2 W/ (m*K), 2.5 W/ (m*K) or 3 W/ (m*K) at room temperature and average humidity. A high heat transfer capacity or a low thermal resistance between the battery cells and the temperature control device can thus be achieved.

The second plastic can in particular be a thermoplastic, an elastomer, a thermoplastic elastomer, silicone or silicone rubber.

To increase the thermal conductivity of the base material of the second plastic, the second plastic can have a filler to increase the thermal conductivity, preferably aluminum oxide or boron nitride.

Preferably, the first plastic and the second plastic are electrically insulating. A material with an electrical conductivity of less than 10 ^-8 S·cm ^-1 or a specific resistance greater than 10 ⁸ Ω·cm can be understood as “insulating”.

The first plastic is preferably a standard plastic or an engineering plastic, preferably polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), polyvinyl chloride (PVC), polybutylene terephthalate (PBT), polyamide (PA), preferably polyamide 6, polyamide, polyamide 6.6, polyamide 11 or polyamide 12, polyvinylidene fluoride (PVDF), ethylene tetrafluoroethylene (ETFE), ethylene vinyl acetate (EVA), chlorinated polyethylene (PE-C), thermoplastic elastomer (TPE), preferably olefin-based thermoplastic elastomer (TPO) polyetherester block copolymer (TPA), polyurethane block copolymer (TPU), polyether block amide (TPA) or thermoplastic styrene block copolymer (TPS), particularly preferably radiation-crosslinked polyethylene (PE), polybutylene terephthalate (PBT), polyamide (PA), the first plastic preferably a at least partially radiation-crosslinked plastic, preferably a radiation-crosslinked plastic with ionizing radiation, preferably beta radiation and/or gamma radiation.

The object set above is also achieved by a vehicle battery arrangement having the features of claim 12 . Advantageous developments result from the present description and the figures.

Accordingly, a vehicle battery arrangement is proposed, comprising a plurality of battery cells, a temperature control device for temperature control of the battery cells, and a cell holder according to one of the above embodiments, wherein the battery cells are held mechanically by the holding section of the cell holder and are thermally connected to the temperature control device by the connection section.

Because the vehicle battery arrangement includes a cell holder according to the invention, the advantages and effects described with regard to the cell holder are also achieved in an analogous manner by the vehicle battery arrangement.

The battery cells are preferably connected directly to the temperature control device via the connection section. In other words, no further material, in particular no gap filler, thermally conductive paste or insulating film, is preferably provided between the battery cells and the connection section and between the connection section and the temperature control device.

character list

• 1 schematisch eine Schnittansicht durch eine Fahrzeugbatterieanordnung mit einem erfindungsgemäßen Zellhalter.

Preferred further embodiments of the invention are explained in more detail by the following description of the figure. It shows:

• 1 schematically a sectional view through a vehicle battery assembly with a cell holder according to the invention.

Detailed description of preferred embodiments

Preferred exemplary embodiments are described below with reference to the figure.

In 1 A vehicle battery assembly 100 is shown schematically. The vehicle battery arrangement 100 includes a plurality of battery cells 7, which are held by two cell holders 1, 13 in a predetermined position relative to one another.

The upper cell holder 13 has a conventional design and accommodates the battery cells 7 in receptacles provided for them in the upper cell holder 13 .

The vehicle battery arrangement 100 also includes a temperature control device 10 for temperature control of the battery cells 7.

The lower cell holder 1 represents a cell holder 1 proposed here A plurality of battery cells 7 formed in a battery module. For this purpose, it comprises a holding section 2 made of a first plastic, formed from a plurality of receptacles 4 arranged next to one another and connected to one another, each for holding a battery cell 7. Attached to the holding section 2 is a connection section 3, which is connected in one piece to the holding section 2, for thermally connecting the in the battery cells 7 held in the receptacles 4 to the temperature control device 10 .

The connection section 3 is formed from a second plastic that is different from the first plastic.

The first plastic has a greater Shore hardness than the second plastic, the difference in Shore hardness preferably being at least 5 Shore C degrees of hardness or 2 Shore D degrees of hardness.

In the present case, the second plastic is a silicone provided with a filler to increase the thermal conductivity, for example aluminum oxide or boron nitride, with an optional hardness of 25 Shore D and an optimal specific thermal conductivity of about 2.5 W/(m*K).

The first plastic is polyamide, it has an optimal hardness of 82 Shore D and an optimal specific thermal conductivity of 0.23 W/ (m*K).

The lower cell holder 1 is a two-component injection molded part consisting of the first plastic and the second plastic.

In the present case, the receptacles 4 of the holding section 2 are designed to receive a cylindrical battery cell 7, specifically on a side surface 5 of the battery cell 7 in relation to a longitudinal axis of the battery cell 7.

In the present case, the connection section 3 represents an essentially plate-shaped component. It forms a base 6 of the cell holder 1 and thus also of the receptacles 4, which are therefore formed as blind holes.

The connection section 3 is designed for surface contacting of a base 14 of the battery cells 7 .

On a side 8 pointing toward the holding section 2, the connection section 3 has a contacting surface for surface thermal contacting of the battery cells 7 and opposite the contacting surface on a side 9 pointing toward the temperature control device 10, a connection surface for surface thermal contacting of a temperature control surface 15 of the temperature control device 10.

In the present case, the temperature control device 10 is designed in the form of a temperature control plate 11 which comprises a plurality of channels 12 through which a temperature control medium flows or can flow.

As far as applicable, all individual features that are presented in the exemplary embodiments can be combined with one another and/or exchanged without departing from the scope of the invention.

Reference List

1

cell holder

2

holding section

3

connection section

4

Recording

5

side of the battery cell

6

bottom of the cell holder

7

battery cell

8th

Side facing the holding section

9

Side facing the temperature control device

10

temperature control device

11

tempering plate

12

channel

13

Upper cell holder

14

bottom of the battery cell

15

tempering surface

100

vehicle battery assembly

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Non-patent Literature Cited

• ISO 7619-1 [0024]
• DIN EN ISO 868 [0024]
• DIN 53505 [0024]

Claims (12)

Cell holder (1) for holding a plurality of battery cells (7) in a battery module, comprising a holding section (2) made of a first plastic, formed from a plurality of receptacles (4) arranged next to one another and connected to one another, each for holding at least one battery cell (7 ), characterized by a connecting section (3) which is formed in one piece with the holding section (2) and is made of a second plastic that is different from the first plastic and adjoins the holding section (2) for thermally connecting the battery cells (7) held in the receptacles (4) to a temperature control device (10). Cell holder (1) according to claim 1 , characterized in that the first plastic has a greater Shore hardness than the second plastic, preferably measured in the form of Shore C or Shore D, the difference in Shore hardness preferably being at least 5 Shore C degrees of hardness or 2 Shore D degrees of hardness, wherein preferably the second plastic has a Shore C hardness in the range from 9 to 65 Shore C and/or the first plastic has a Shore C hardness greater than or equal to 60 Shore C, and/or preferably the second plastic has a Shore D hardness in the range from 6 to 44 Shore D and/or the first plastic has a Shore D hardness greater than 40 Shore D, preferably greater than 45 Shore C and/or the first plastic has a Shore D hardness in the range from 40 to 95 Shore D. Cell holder (1) according to claim 1 or 2 , characterized in that the cell holder (1) is a two-component injection-molded part, the holding section (2) preferably being primary formed in a first injection molding step and the connection section (3) being primary formed integrally with the retaining section (2) in a second injection molding step , or preferably in a first injection molding step the connection section (3) was primary formed and in a second injection molding step the holding section (2) cohesively with the connection section (3) was primary formed. Cell holder (1) according to one of the preceding claims, characterized in that the receptacles (4) are arranged next to one another in one plane, with the connection section (3) preferably adjoining the holding section (2) in a direction transverse to the plane. Cell holder (1) according to one of the preceding claims, characterized in that the receptacles (4) of the holding section (2) are designed to receive a cylindrical battery cell (7), a prismatic battery cell or a pouch battery cell, and/or the receptacles ( 4) of the holding section (2) for holding a battery cell (7) on a side face (5) of the battery cell (7) relative to a longitudinal axis of the battery cell (7). Cell holder (1) according to one of the preceding claims, characterized in that the connection section (3) is designed for surface contacting of a base (14) of the battery cells (7), or for surface contacting of a base (14) and a base (14) on the base (14) subsequent side surface portion of the battery cells (7) is formed. Cell holder (1) according to one of the preceding claims, characterized in that the connection section (3) is essentially plate-shaped, and/or the connection section (3) has a contacting surface for the preferably flat surface on a side (8) pointing towards the holding section (2). thermal contacting of the battery cells (7) and opposite the contacting surface has a connection surface for preferably areal thermal contacting of the temperature control device (10), preferably a temperature control surface (15) of the temperature control device (10). Cell holder (1) according to one of the preceding claims, characterized in that the second plastic has a higher specific thermal conductivity than the first plastic, preferably at least 0.5 W/(m*K), preferably at least 1 W/(m*K). K), particularly preferably at least 1.5 W / (m * K), very particularly preferably at least 2 W / (m * K) higher specific thermal conductivity at room temperature and average humidity, and / or the second plastic preferably has a specific thermal conductivity of at least 0.5 W/(m*K), preferably at least 1 W/(m*K), particularly preferably at least 1.5 W/(m*K), very particularly preferably at least 2 W/(m*K), 2.5 W/ (m*K) or 3 W/ (m*K) at room temperature and medium humidity. Cell holder (1) according to one of the preceding claims, characterized in that the second plastic is a thermoplastic, an elastomer, a thermoplastic elastomer, silicone or silicone rubber, and/or preferably the second plastic has a filler to increase the thermal conductivity, preferably aluminum oxide or boron nitride. Cell holder (1) according to one of the preceding claims, characterized in that the first plastic and/or the second plastic is electrically insulating. Cell holder (1) according to one of the preceding claims, characterized in that the first plastic is a standard plastic or an engineering plastic, preferably polyethylene (PE), polypropylene (PP), polymethylpentene (PMP), polyvinyl chloride (PVC), polybutylene terephthalate (PBT) , Polyamide (PA), preferably polyamide 6, polyamide, polyamide 6.6, polyamide 11 or polyamide 12, polyvinylidene fluoride (PVDF), ethylene tetrafluoroethylene (ETFE), ethylene vinyl acetate (EVA), chlorinated polyethylene (PE-C), thermoplastic elastomer (TPE ), preferably olefin-based thermoplastic elastomer (TPO), polyetherester block copolymer (TPA), polyurethane block copolymer (TPU), polyether block amide (TPA) or thermoplastic styrene block copolymer (TPS), particularly preferably radiation-crosslinked polyethylene (PE), polybutylene terephthalate (PBT ), Polyamide (PA), wherein the first plastic is preferably an at least partially radiation-crosslinked plastic. Vehicle battery arrangement (100), comprising a plurality of battery cells (7) and a temperature control device (10) for temperature control of the battery cells (7), characterized in that the battery cells (7) are held by the holding section (2) of a cell holder (1) according to one of above claims are held mechanically and are thermally connected to the temperature control device (10) by the connection section (3) of the cell holder (1).

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