Patent Description:
The present disclosure is additionally directed to an electric battery cell for such a battery assembly.

The present disclosure is also directed to a vehicle comprising a battery assembly.

A coolant being guided in the coolant channel may be used to heat or cool the battery cells of the battery assembly. If the coolant is used for cooling, heat from the battery cells is transferred into the coolant. If the coolant is used for heating, heat from the coolant is transferred into the battery cells. Cooling and heating of battery cells may be summarized as thermal management of battery cells. This is necessary in order to be able to provide a desired electrical performance of the battery cells.

An electric battery cell according to the preamble of claim <NUM> is known from <CIT>.

It is an objective of the present disclosure to further improve the thermal management of battery cells.

According to a first aspect, there is provided an electric battery cell for a battery assembly. The electric battery cell comprises at least a first electrode being electrically connected to a first cell terminal and a second electrode being electrically connected to a second cell terminal. Each of the first cell terminal and the second cell terminal comprises an electric connection surface for electrically connecting the respective first cell terminal or second cell terminal. Moreover, at least one of the first cell terminal and the second cell terminal comprises a thermal connection surface being separate from the respective electric connection surface. The thermal connection surface is configured to transfer heat. Again, the fact that the thermal connection surface is separate from the respective electric connection surface means that the thermal connection surface and the respective electric connection surface are overlap-free. Thus, different surfaces of the respective first cell terminal or second cell terminal are used for the electric connection and the thermal connection. Consequently, the active parts of the battery cell, i.e. the electrodes and the electrolyte, may be heated or cooled via the thermal connection surface in a direct manner. This applies in a geometric sense, since the thermal connection surface is geometrically arranged very close to the electrodes and the electrolyte. Moreover, this applies in a thermal sense since only a comparatively little thermal resistance exists between the thermal connection surface and the active parts of the battery cell. This renders the cooling or heating of the battery cell very efficient. This means that comparatively little energy is required in order to achieve a pre-defined cooling effect or heating effect.

According to present disclosure, the electric connection surface and the thermal connection surface of at least one of the first cell terminal and the second cell terminal are arranged on adjacent sides of the respective first cell terminal or second cell terminal. In this context, adjacent sides of cell terminals are to be understood as sides of a cell terminal that share a common edge. An angle between such sides is for example <NUM>°. In this configuration, the electric connection surface and the thermal connection surface may be arranged in a very compact manner.

If such an electric battery cell is used in a battery assembly, e.g. a battery assembly according to the present disclosure, an electric conductor or bus bar may be connected to the electric connection surface and a coolant channel may be thermally coupled to the thermal connection surface. In such a configuration, the electric conductor may at least partially extend over the coolant channel. Alternatively, the coolant channel may extend at least partially over the electric conductor.

According to the present disclosure, the electric connection surface and the thermal connection surface of at least one of the first cell terminal and the second cell terminal are arranged on opposite sides of the respective first cell terminal or second cell terminal. Also in this example, the electric connection surface and the thermal connection surface are arranged in a compact manner. Additionally, this configuration allows to provide a comparatively big electric connection surface and a comparatively big thermal connection surface on a given cell terminal.

If such an electric battery cell is used in a battery assembly, e.g. a battery assembly according to the present disclosure, an electric conductor may be electrically connected to the electric connection surface and a coolant channel may be thermally coupled to the thermal connection surface. Consequently, the electric conductor and the coolant channel are connected to opposite sides of the respective first cell terminal or second cell terminal. Such a configuration is comparatively compact.

electric battery cell according to the present disclosure is an electric battery cell for a vehicle, especially for propelling a vehicle.

each of the first cell terminal and the second cell terminal comprises a thermal connection surface being configured to transfer heat. Consequently, the battery cell may be heated or cooled via both the first cell terminal and the second cell terminal. In doing so, the cooling performance or heating performance may be enhanced.

When forming part of a battery assembly, the thermal connection surface of the first cell terminal and the thermal connection surface of the second cell terminal may be thermally coupled to the same coolant channel. Alternatively, the thermal connection surface of the first cell terminal and the thermal connection surface of the second cell terminal may be thermally coupled two different coolant channels. In this context, a first coolant channel may be thermally coupled to a first group of cell terminals and a second coolant channel may be thermally coupled to a second group of cell terminals.

In an example, at least one of the first cell terminal and the second cell terminal is tab-shaped or pin-shaped. Cell terminals being tab-shaped or pin-shaped are known as such. In the present context, such a cell terminal has an electric connection surface and a thermal connection surface. Both pin-shaped terminals and tab-shaped terminals offer the possibility to arrange the electric connection surface and the thermal connection surface in a compact manner.

In an example, the electric connection surface and the thermal connection surface of at least one of the first cell terminal and the second cell terminal are arranged on the same side of the respective first cell terminal or second cell terminal. In this context, an edge of the electric connection surface and an edge of the thermal connection surface may contact each other. Alternatively, a gap is provided between the electric connection surface and the thermal connection surface. Arranging the electric connection surface and the thermal connection surface on the same side of the respective first cell terminal or second cell terminal has the advantage that both the electric connection surface and the thermal connection surface are accessible from the same side. This facilitates the assembly of the battery cells within a battery assembly.

In an example, at least one of the first cell terminal and the second cell terminal comprises two or more thermal connection surfaces being separate from one another. Consequently, a comparatively big total thermal connection surface may be provided. This enhances the cooling performance or the heating performance via the total of the thermal connection surfaces. In an example, the electric connection surface may be arranged between two thermal connection surfaces.

In an example, a thermal interface material may be arranged on at least one thermal connection surface. A thermal conductivity of the thermal interface material exceeds the thermal conductivity of the first cell terminal or the second cell terminal comprising the thermal connection surface on which the thermal interface material is arranged. Using a thermal interface material enhances the thermal conductivity of thermal connection surface. Consequently, heat transfer over the thermal connection surface is facilitated. In an example, the thermal interface material is a solder material.

In a case in which the electric battery cell is used in a battery assembly, e.g. a battery assembly according to the present disclosure, the coolant channel may be connected to the thermal connection surface via the thermal interface material. In other words, the thermal interface material is interposed between the thermal connection surface and the coolant channel. This leads to a comparatively low thermal resistance between the interior of the coolant channel and the thermal connection surface.

In an example, a ceramic spacer part is positioned on at least one thermal connection surface. An electric conductivity of the first cell terminal or the second cell terminal on which the ceramic spacer is positioned is at least double the electric conductivity of the ceramic spacer part. In other words, the ceramic spacer part is an electric isolator. Thus, the ceramic spacer part helps to electrically isolate components which are to be coupled to the thermal connection surface.

In a case in which the electric battery cell is used in a battery assembly, e.g. a battery assembly according to the present disclosure, the ceramic spacer part may be interposed between the thermal connection surface and the coolant channel.

It is noted, that a thermal conductivity of the ceramic spacer part may be comparatively high. For example, the thermal conductivity of the ceramic spacer part may be at least double the thermal conductivity of the first cell terminal or the second cell terminal on which the ceramic spacer is positioned. Consequently, the ceramic spacer part may facilitate the heat exchange with the thermal connection surface.

It is further noted, that the thermal interface material and the ceramic spacer part may be used in combination. In this context, the thermal interface material is arranged between the thermal connection surface and the ceramic spacer part. The thermal interface material may additionally be used in order to mechanically connect the ceramic spacer part to the thermal connection surface. Thus, if the electric battery cell is used in a battery assembly, e.g. a battery assembly according to the present disclosure, the thermal interface material and the ceramic spacer part are arranged between the coolant channel and the thermal connection surface.

In an example, the ceramic spacer part comprises an aluminum nitride material or a silicon nitride material. These materials offer a good combination of a comparatively low electric conductivity and a comparatively high thermal conductivity. In simplified words, these materials are electric isolators and thermal conductors.

According to a second aspect, there is provided a battery assembly comprising at least one electric battery cell and at least one coolant channel being configured to guide a coolant. The at least one electric battery cell comprises at least a first electrode being electrically connected to a first cell terminal and a second electrode being electrically connected to a second cell terminal. Each of the first cell terminal and the second cell terminal comprises an electric connection surface for electrically connecting the respective first cell terminal or second cell terminal. Moreover, at least one of the first cell terminal and the second cell terminal comprises a thermal connection surface being separate from the respective electric connection surface. The coolant channel is thermally coupled to the thermal connection surface of the at least one electric battery cell. In the present context, the fact that the thermal connection surface is separate from the respective electric connection surface means that the thermal connection surface and the respective electric connection surface are overlap-free. At the same time, the thermal connection surface is arranged on at least one of the first connection terminal and the second connection terminal. Consequently, the coolant flowing in the coolant channel is able to cool or heat the active parts of the battery cell, i.e. the electrodes and the electrolyte, in a direct manner. This applies in a geometric sense, since the thermal connection surface is geometrically arranged very close to the electrodes and the electrolyte. Moreover, this applies in a thermal sense since only a comparatively little thermal resistance exists between the thermal connection surface and the active parts of the battery cell. This renders the cooling or heating of the battery cell very efficient. This means that comparatively little energy is required in order to achieve a pre-defined cooling effect or heating effect.

In an example, the battery assembly is a battery assembly for a vehicle, especially for propelling a vehicle. In this context, the battery assembly may be called a traction battery assembly.

In an example, the battery cells of the battery assembly are prismatic battery cells.

The electrodes and the electrolyte may be called a jellyroll or jelly stack.

In an example, the coolant channel is made from a plastic material. Consequently, the coolant channel may be designed in a lightweight manner. Additionally, a geometry of such a coolant channel may be chosen in a comparatively free manner. Thus, the geometry of the coolant channel may be easily adapted to given spaces in a given application. In other words, the coolant channel may be designed in a compact manner.

In an example, the plastic material is a polyamide material, especially a polyamide <NUM> material.

The plastic material may have a thermal conductivity of <NUM> W/(m K) to <NUM> W/(m K), preferably <NUM>,<NUM> W/(m K) to <NUM>,<NUM> W/(m K), in a flow direction. In an example, the plastic material has a thermal conductivity of <NUM>,<NUM> W/(m K) in the flow direction.

The plastic material may have a thermal conductivity of <NUM> W/(m K) to <NUM> W/(m K), preferably <NUM>,<NUM> W/(m K) to <NUM>,<NUM> W/(m K), in a crossflow direction. In an example, the plastic material has a thermal conductivity of <NUM>,<NUM> W/(m K) in the crossflow direction.

The plastic material may have a thermal conductivity of <NUM>,<NUM> W/(m K) to <NUM> W/(m K), preferably <NUM> W/(m K) to <NUM>,<NUM> W/(m K), in a through plane direction. In an example, the plastic material has a thermal conductivity of <NUM>,<NUM> W/(m K) in the through plane direction.

The plastic material may have a dielectric constant of <NUM>,<NUM> to <NUM>,<NUM>, preferably <NUM> to <NUM>, at a frequency of <NUM>. In an example, the plastic material has a dielectric constant of <NUM>,<NUM>.

In an example, the battery assembly comprises at least two electric battery cells. The coolant channel is thermally coupled to the thermal connection surfaces of all of the at least two electric battery cells. Thus, one coolant channel may be used in order to cool or heat a plurality of battery cells. This renders the battery assembly structurally simple and compact.

In an example, the at least two electric battery cells are electrically connected by an electric conductor electrically connecting an electric connection surface of each of the at least two electric battery cells. The electric conductor and the coolant channel are formed integrally. In this context, the electric conductor may also be called a bus bar. By forming the bus bar integrally with the coolant channel, the battery assembly is very compact. Additionally, the assembly of the battery assembly is facilitated since the electric conductor and the coolant channel may be assembled to the battery cells in one step.

In an example, the battery assembly further comprises a cooling means being arranged on a side adjacent or opposite to the side of the at least one electric battery cell carrying the respective first and second electric cell terminal. It is emphasized that this cooling means is separate from the coolant channel as mentioned above. This means that the coolant channel does not form part of the cooling means. The location of the cooling means may also be referred to as outside a cell can. The cooling means for example comprises a cooling plate, i.e. a plate comprising a coolant channel. If such a plate is arranged on a side of a battery cell and if coolant flows through the coolant channels of the plate, the battery cell may be heated or cooled. Consequently, the cooling means may be used to additionally cool or heat the battery cells.

According to a third aspect, there is provided a vehicle comprising a battery assembly according to the present disclosure. This means, that the vehicle also comprises at least one electric battery cell according to the disclosure. The battery assembly and the at least one electric battery cell may be used for propelling the vehicle. Since the cooling or heating of the at least one electric battery cell and the battery assembly is very efficient, the vehicle may be operated in a very efficient manner. Consequently, the vehicle may have a comparatively high driving range.

The battery assembly <NUM> comprises a total of twelve identical electric battery cells <NUM> (see also <FIG>).

The electric battery cells <NUM> are arranged side-by-side along a line-up direction <NUM>.

Furthermore, all electric battery cells <NUM> are placed on a cooling means <NUM> which has the form of a cooling plate <NUM>. The cooling plate <NUM> comprises a network of internal coolant channels which can be supplied with coolant via a coolant port 18a.

The cooling plate <NUM> is arranged on a bottom side of each of the battery cells <NUM>. In other words, all battery cells <NUM> are located on top of the cooling plate <NUM>.

It is noted that in the examples shown in the Figures, the cooling means <NUM>, i.e. the cooling plate <NUM>, is optional. The battery cells <NUM> may be sufficiently cooled via the respective thermal connection surfaces which are arranged on the cell terminals of each battery cell <NUM> as will be explained below.

On a respective upper side, each of the battery cells <NUM> comprises a first cell terminal <NUM> and a second cell terminal <NUM>.

The first cell terminal <NUM> is electrically connected to an electrode <NUM>. It is understood, that the first cell terminal <NUM> may also be electrically connected to a plurality of first electrodes. In the representation of <FIG>, the first electrode <NUM> is representative of this plurality of electrodes.

The second cell terminal <NUM> is electrically connected to an electrode <NUM>. It is understood, that the second cell terminal <NUM> may also be electrically connected to a plurality of second electrodes. In the representation of <FIG>, the second electrode <NUM> is representative of this plurality of electrodes.

In an example, the first cell terminal <NUM> is a negative terminal which may also be referred to as the minus pole of the electric battery cell <NUM>. Then, the first electrodes <NUM> are anodes. The second cell terminal <NUM> is a positive terminal which may also be referred to as the plus pole of the electric battery cell <NUM>. The second electrodes <NUM> are cathodes.

In the example shown in the Figures, the first cell terminal <NUM> and the second cell terminal <NUM> are tab-shaped (see especially <FIG> and <FIG>). It is understood that also cell terminals <NUM>, <NUM> of other shapes are possible, especially pin-shaped cell terminals <NUM>, <NUM>.

The first cell terminal <NUM> comprises an electric connection surface <NUM>.

The second cell terminal <NUM> comprises an electrical connection surface <NUM>.

Within the battery assembly <NUM>, the electric battery cells <NUM> are connected in series.

To this end, the electric battery cells <NUM> are arranged in alternating orientations and neighboring first cell terminals <NUM> and second cell terminals <NUM> of neighboring electric battery cells <NUM> are electrically connected via an electric conductor <NUM> respectively. The electric conductor <NUM> may also be designated a bus bar. The electric conductors <NUM> also form part of the battery assembly <NUM>.

Even though the battery assembly <NUM> comprises a total of twelve electric battery cells <NUM> and a total of thirteen electric conductors <NUM>, the following explanations will be focused on one single electric battery cell <NUM> and its connections (cf.

One of the electric conductors <NUM> is electrically connected to the electric connection surface <NUM> and the electric connection surface <NUM> respectively, e.g. by spot welding.

Beyond that, each of the first cell terminal <NUM> and the second cell terminal <NUM> comprises a thermal connection surface. In this context, the thermal connection surface of the first cell terminal <NUM> is designated with reference sign <NUM> and the thermal connection surface of the second cell terminal <NUM> is designated with reference sign <NUM>.

It has to be noted that the thermal connection surface <NUM> of the first cell terminal <NUM> is separate from the electric connection surface <NUM> of the first cell terminal <NUM>. This means that the thermal connection surface <NUM> and the electric connection surface <NUM> do not overlap.

Also the thermal connection surface <NUM> of the second cell terminal <NUM> is separate from the electric connection surface <NUM> of the second cell terminal <NUM>. This means that the thermal connection surface <NUM> and the electric connection surface <NUM> do not overlap.

The battery assembly <NUM> also comprises two coolant channels <NUM>, <NUM>.

Coolant channel <NUM> is arranged adjacent to a first end 10a of the upper side of the electric battery cells <NUM>. Moreover, coolant channel <NUM> is thermally coupled to all the thermal connection surfaces <NUM>, <NUM> which are arranged proximate to the first end 10a.

Coolant channel <NUM> is arranged adjacent to a second end 10b of the upper side of the electric battery cells <NUM>. The second end 10b is opposed to the first end 10a. Coolant channel <NUM> is thermally coupled to all the thermal connection surfaces <NUM>, <NUM> which are arranged proximate to the second end 10b.

The coolant channels <NUM>, <NUM> are both configured to guide a coolant and are arranged substantially parallel.

Both coolant channels <NUM>, <NUM> are made from plastic material.

The coolant channels <NUM>, <NUM> do not directly abut against the respective thermal connection surface <NUM>, <NUM>. Rather, on each of the thermal connection surfaces <NUM>, <NUM> a thermal interface material <NUM> is provided.

The objective of using the thermal interface material <NUM> is to enhance the thermal conductivity of the thermal connection surfaces <NUM>, <NUM>. The thermal interface material <NUM> has a thermal conductivity which exceeds the thermal conductivity of the first cell terminal <NUM> and the second cell terminal <NUM>.

Moreover, a ceramic spacer part <NUM> is interposed between each of the thermal connection surfaces <NUM>, <NUM> and the respective coolant channel <NUM>, <NUM>.

The objective of using such a ceramic spacer part <NUM> is to electrically isolate the coolant channels <NUM>, <NUM> from the first cell terminal <NUM> and the second cell terminal <NUM> respectively. At the same time, thermal conductivity shall not be hindered. Therefore, an electric conductivity of the first cell terminal <NUM> and the second cell terminal <NUM> is at least double the electric conductivity of the ceramic spacer part <NUM>.

In the present example, the ceramic spacer part <NUM> comprises an aluminum nitride material or a silicon nitride material.

The thermal interface material <NUM> is a solder material. It is additionally used to mechanically join the ceramic spacer part <NUM> on the respective thermal connection surface <NUM>, <NUM>. Furthermore, the ceramic spacer part <NUM> may be connected to the respective coolant channel <NUM>, <NUM> by soldering.

It is noted that in the Figures the thickness of the thermal interface material <NUM> and the ceramic spacer part <NUM> is artificially increased with respect to reality.

<FIG> shows an alternative battery assembly <NUM>. For the ease of representation, only the surroundings of one cell terminal, which can be a first cell terminal <NUM> or a second cell terminal <NUM>, are represented.

In the following, only the differences with respect to the example of <FIG> will be explained.

As before, the electric connection surface <NUM>, 30and the thermal connection surface <NUM>, <NUM> of the cell terminal <NUM>, <NUM> are arranged on the same side of the cell terminal <NUM>, <NUM>.

However, in contrast to the example of <FIG>, now the thermal connection surface <NUM>, <NUM> is arranged closer to an end of the upper side of the respective electric battery cell <NUM> than the electric connection surface <NUM>, <NUM>. In other words, the order of the electric connection surface <NUM>, <NUM> and the associated thermal connection surface <NUM>, <NUM> is inversed.

<FIG> shows a further alternative battery assembly <NUM>. Again, for the ease of representation, only the surroundings of one cell terminal are represented. The cell terminal can be a first cell terminal <NUM> or a second cell terminal <NUM>.

In the example of <FIG>, the cell terminal <NUM>, <NUM> is pin-shaped.

The electric connection surface <NUM>, <NUM> is arranged on an upper surface of the cell terminal <NUM>, <NUM>.

The thermal connection surface <NUM>, <NUM> is arranged on a side which is adjacent to the side on which the electric connection surface <NUM>, <NUM> is positioned.

In the example of <FIG>, the thermal connection surface <NUM>, <NUM> is positioned on a lateral side of the cell terminal <NUM>, <NUM>.

This has the effect that in a situation in which the electric conductor <NUM> is connected to the electric connection surface <NUM>, <NUM> and the coolant channel <NUM>, <NUM> is thermally coupled to the thermal connection surface <NUM>, <NUM>, the coolant channel <NUM>, <NUM> is arranged between the electric conductor <NUM> and the electric battery cell <NUM>.

In contrast to the previous examples, now the electric connection surface <NUM>, <NUM> and the thermal connection surface <NUM>, <NUM> are arranged on opposite sides of the respective cell terminal <NUM>, <NUM>.

<FIG> shows another alternative battery assembly <NUM>. Again, for the ease of representation, only the surroundings of one cell terminal are represented. The cell terminal can be a first cell terminal <NUM> or a second cell terminal <NUM>.

The example of <FIG> is similar to the example of <FIG> and the example of <FIG>. This means that again, the electric connection surface <NUM>, <NUM> and the thermal connection surface <NUM>, <NUM> are arranged on the same side of the cell terminal <NUM>, <NUM>. As before, the cell terminal can be a first cell terminal <NUM> or a second cell terminal <NUM>.

However, in contrast to the above examples, in the example of <FIG> two thermal connection surfaces 34a, 34b, 36a, 36b are provided on the cell terminal <NUM>, <NUM>. The thermal connection surface 34a, 36a and the thermal connection surface 34b, 36b are separate from one another. Furthermore, separate coolant channels 38a, 40a and 38b, 40b are provided. They are thermally coupled to the separate thermal connection surface 34a, 36a and 34b, 36b respectively.

The electric connection surface <NUM>, <NUM> is arranged between the thermal connection surface 34a, 36a and the thermal connection surface 34b, 36b.

Moreover, in the example of <FIG>, an electric conductor <NUM> having a T-shaped cross-section is used. This electric conductor <NUM> contacts the electric connection surface <NUM>, <NUM> with the foot of the T-shaped cross-section. The upper part of the electric conductor <NUM> covers the coolant channel 38a, 40a and the coolant channel 38b, 40b.

In all the examples shown in <FIG>, the electric conductor <NUM> and the coolant channels <NUM>, <NUM> are formed integrally. This means that the coolant channel and the electric conductor <NUM> are portions of the same part. This is illustrated using dashed lines.

Claim 1:
An electric battery cell (<NUM>) for a battery assembly (<NUM>), the electric battery cell (<NUM>) comprising at least a first electrode (<NUM>) being electrically connected to a first cell terminal (<NUM>) and a second electrode (<NUM>) being electrically connected to a second cell terminal (<NUM>),
wherein each of the first cell terminal (<NUM>) and the second cell terminal (<NUM>) comprises an electric connection surface (<NUM>, <NUM>) for electrically connecting the respective first cell terminal (<NUM>) or second cell terminal (<NUM>),
characterized in that at least one of the first cell terminal (<NUM>) and the second cell terminal (<NUM>) comprises a thermal connection surface (<NUM>, <NUM>) being separate from the respective electric connection surface (<NUM>, <NUM>), wherein the thermal connection surface (<NUM>, <NUM>) is configured to transfer heat, and
wherein the electric connection surface (<NUM>, <NUM>) and the thermal connection surface (<NUM>, <NUM>) of at least one of the first cell terminal (<NUM>) and the second cell terminal (<NUM>) are arranged on adjacent or opposite sides of the respective first cell terminal (<NUM>) or second cell terminal (<NUM>).