BATTERY MODULE FOR A TRACTION BATTERY OF AN ELECTRIC VEHICLE, TRACTION BATTERY FOR AN ELECTRIC VEHICLE, AND METHOD OF MANUFACTURING SUCH A TRACTION BATTERY

Abstract

A battery module for a traction battery of an electric vehicle is disclosed. The battery module includes a heat transfer surface for tempering cells of the battery module and at least one cavity disposed between partial surfaces of the heat transfer surface for receiving excess heat conductive material.

Claims

1. A battery module for a traction battery of an electric vehicle, the battery module comprising: at least one heat transfer surface configured to temper cells of the battery module; and at least one cavity arranged between partial surfaces of the heat transfer surface and configured to receive excess heat conducting material.

2. The battery module according to claim 1, wherein the cavity is a pocket in the heat transfer surface and the sub-surfaces surround the cavity.

3. The battery module according to claim 1, wherein the cavity is arranged between two fins of the heat transfer surface, and the sub-surfaces are disposed on the fins.

4. The battery module according to claim 1, wherein the partial surfaces are formed by end portions, disposed outside gaps between the cells, of heat conducting sheets of the battery module disposed in the gaps.

5. The battery module according to claim 4, wherein the end portions are bent transversely to a main extension plane of the heat conducting sheets.

6. The battery module according to claim 4, wherein the end portions are slotted.

7. The battery module according to claim 4, wherein each two adjacent end portions form a rib.

8. The battery module according to claim 1, wherein the sub-surfaces are oriented at an acute angle to a reference plane of the heat transfer surface.

9. A traction battery for an electric vehicle, the traction battery comprising: a temperature control device; at least one battery module comprising at least one heat transfer surface configured to temper cells of the battery module and at least one cavity arranged between partial surfaces of the heat transfer surface and configured to receive excess heat conducting material; wherein the battery module is thermally coupled to the temperature control device using a heat conductive material, and wherein excess thermally conductive material is displaced from a contact region between the partial surfaces of the heat transfer surface of the battery module and the temperature control device into the at least one cavity of the battery module.

10. A method of manufacturing a traction battery, comprising the steps of: arranging a temperature control device in the traction battery; arranging at least one battery module in the traction battery, the traction battery comprising at least one heat transfer surface configured to temper cells of the battery module and at least one cavity arranged between partial surfaces of the heat transfer surface and configured to receive excess heat conducting material; metering pasty heat conductive material into a contact area between partial surfaces of a heat transfer surface of at least one battery module and a temperature control device, placing the heat transfer surface on the temperature control device and pressing the temperature control device with a setting force, wherein the battery module is thermally coupled to the temperature control device using a heat conductive material, wherein excess thermally conductive material is displaced from a contact region between the partial surfaces of the heat transfer surface of the battery module and the temperature control device into the at least one cavity of the battery module, and wherein the heat conductive material is at least partially displaced from the contact area into the at least one cavity of the battery module.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0026] Further advantages, features, and details of the various embodiments of this disclosure will become apparent from the ensuing description of a preferred exemplary embodiment and with the aid of the drawings. The features and combinations of features recited below in the description, as well as the features and feature combination shown after that in the drawing description or in the drawings alone, may be used not only in the particular combination recited, but also in other combinations on their own, without departing from the scope of the disclosure.

[0027] An advantageous embodiment of the present invention is set out below with reference to the accompanying figures, wherein:

[0028] FIG. 1 depicts a representation of a battery module according to an embodiment example; and

[0029] FIG. 2 depicts a sectional view of a traction battery according to an embodiment.

[0030] The figures are merely schematic representations and serve only to explain the invention. Identical or similarly acting elements are marked throughout with the same reference signs.

DETAILED DESCRIPTION OF THE INVENTION

[0031] As used throughout the present disclosure, unless specifically stated otherwise, the term “or” encompasses all possible combinations, except where infeasible. For example, the expression “A or B” shall mean A alone, B alone, or A and B together. If it is stated that a component includes “A, B, or C”, then, unless specifically stated otherwise or infeasible, the component may include A, or B, or C, or A and B, or A and C, or B and C, or A and B and C. Expressions such as “at least one of” do not necessarily modify an entirety of the following list and do not necessarily modify each member of the list, such that “at least one of “A, B, and C” should be understood as including only one of A, only one of B, only one of C, or any combination of A, B, and C.

[0032] FIG. 1 depicts an illustration of a battery module 100 according to an embodiment. Several such battery modules 100 can be connected in parallel and/or in series in a traction battery of an electric vehicle. For this purpose, the individual battery modules 100 are inserted into a housing or frame of the traction battery and electrically connected to one another. For tempering the battery modules 100, the traction battery has a tempering device, which can be arranged in a bottom of the housing, for example, or can form the bottom of the traction battery. The battery modules 100 are thermally coupled to the temperature control device using a thermal conductive material. In particular, the temperature control device may be used to cool the battery modules 100. At low temperatures, the temperature control device may also be used to heat the battery modules 100.

[0033] The battery module 100 includes a plurality of pouch cells or prismatic cells 102. The cells 102 are arranged flat side to flat side, side by side, within a housing 104 of the battery module 100. The flat sides of the cells 102 are oriented perpendicular to a heat transfer surface 106 of the battery module 100. The heat transfer surface 106 is thus arranged here at a bottom of the housing 104. The battery module can be coupled to the temperature control device of the traction battery via the heat transfer surface 106.

[0034] Alternatively, the cells 102 may be stacked horizontally on top of each other. In that case, the battery module 100 may have at least one lateral heat transfer surface 106. Depending on the design of the temperature control device, the battery module 100 may also have multiple heat transfer surfaces 106.

[0035] In the approach presented herein, the heat transfer surface 106 is divided into a plurality of sub-surfaces 108. The partial surfaces 108 define a contact area to the temperature control device. Cavities 110 are disposed between the partial surfaces 108. The cavities 110 are recesses behind a main extension plane of the heat transfer surface 106. The cavities 110 interrupt the contact area. The cavities 110 are configured to receive excess heat transfer material during assembly of the traction battery, which is disposed between the partial surfaces 108 and the temperature control device to thermally connect the battery module 100 to the temperature control device.

[0036] The thermally conductive material is pasty at least during assembly of the traction battery, completely filling a gap between the partial surfaces 108 and a surface of the temperature control device when the battery module 100 is placed on the temperature control device and pressed against the temperature control device with a setting force. Upon pressing, the paste flows along the gap and excess heat conductive material can swell out of the gap into the adjacent cavity.

[0037] The heat transfer surface 106, which is divided into the partial surfaces 108, results in short flow paths to the next cavity 110. Due to the short flow paths, only a low pressure builds up within the pasty heat transfer material between the temperature control unit and the partial surfaces 108 when the battery module 100 is pressed against the temperature control unit. Due to the low pressure, a low setting force is required to press the battery module 100. The tempering device is subjected to only a small amount of stress due to the low setting force.

[0038] Here, the housing 104 is open at the heat transfer surface 106 and the partial surfaces 108 are formed by bent end portions 112 of heat baffles 114 disposed between the cells 102. Here, the heat baffles 114 are disposed between every other cell 102 and the end portions 112 of adjacent heat baffles 114 are bent in opposite directions. As a result, two each of the end portions 112 projecting between the cells form ribs 116 between which cavities 110 are disposed. The cells 102 are exposed in the cavities 110. The cavities 110 form channels 118 between the ribs 116. The channels 118 extend to the edge of the heat transfer surface 106. Air trapped between the battery module 100 and the temperature control device can escape laterally through the channels 118.

[0039] In an alternative embodiment, the housing 104 is closed at the heat transfer surface 106 and the heat transfer surface 106 is a continuous side of the housing 104. The partial surfaces 108 are contiguous and the cavities 110 are formed as recesses in the heat transfer surface 106. The depressions may be referred to as pockets.

[0040] In one embodiment, the end regions 112 of the heat conducting sheets 114 are slotted. As a result, each end region 112 forms a plurality of partial surfaces 108. The individual sub-surfaces 108 can thus deform individually during press-off without affecting the adjacent sub-surfaces 108.

[0041] FIG. 2 shows a sectional view of a section of a traction battery 200 according to an embodiment. The traction battery 200 has a temperature control device 202 and at least one battery module 100. The battery module 100 is substantially the same as the battery module in FIG. 1. The battery module 100 is thermally coupled to the temperature control device 202 using thermal conductive material 204. The thermally conductive material 204 bridges gaps 206 between the sub-surfaces 108 of the heat transfer surface 106 and the temperature control device 202. Excess thermally conductive material 204 has been displaced laterally from the gaps 206 into the cavities 110 located between the sub-surfaces 108.

[0042] In one embodiment, the partial surfaces 108 are oriented at a slight angle to the surface of the temperature control device 202. As a result, the gaps 206 taper from the adjacent cavity 110 to an acute angle. The acute angle of the gaps 206 has facilitated lateral displacement of the thermally conductive material 204 into the cavities 110, as the widest point of the gaps 206 is directly adjacent to the respective cavity 110.

[0043] In other words, a flow path optimized bottom structure of a battery module is presented.

[0044] When placing cell modules in a battery housing, a gap filler is used for homogeneous thermal connection to a cooling area (e.g. cooling plate). This paste-like material is applied to the connection surface and then compressed when the modules are placed. To ensure that the gap filler can flow evenly and the excess can be displaced to the side edges of the module, the modules have so far been inserted into the battery frame with very high setting forces, which can lead to deformation or undesirable deformation of the components. For this reason, additional mounting aids have so far been used to counteract the setting forces. Furthermore, a long holding force has been necessary up to now so that the gap filler can overcome the long flow distances.

[0045] In the approach presented here, cavities are provided on the thermal contact surface which can absorb excess gap filler during setting, thus enabling very short flow paths and greatly reducing the setting forces. Furthermore, the short flow paths allow faster setting and thus shorter cycle times.

[0046] The cell module presented here has cavities on the thermal bonding surface into which the gap filler is partially displaced during placement. The cavities can be formed by a rib structure. Alternatively, the cavities may be formed as pockets. The cavities can be arranged in such a way that the flow path of the gap filler is reduced to at most 50 mm. In particular, the cavities may be arranged such that the flow path of the gap filler is reduced to at most 20 mm. The cell module may comprise pouch cells or prismatic cells. The cells may be lithium cells for a vehicle. The bottom structure can be formed by the heat conducting sheets.

[0047] Since the devices and methods described in detail above are examples of embodiments, they can be modified to a wide extent by the skilled person in the usual manner without leaving the scope of the invention. In particular, the mechanical arrangements and the proportions of the individual elements with respect to each other are merely exemplary. Some preferred embodiments of apparatus according to the invention have been disclosed above. The invention is not limited to the solutions explained above, but the innovative solutions can be applied in different ways within the limits set by the claims.