Temperature regulating device

Abstract

A temperature regulating device is described, which has individual battery cells (2) assembled into modules, which are arranged in a flow channel (3) through which a temperature regulating fluid flows in a main flow direction (6). In order to design a temperature regulating device of the type mentioned at the outset in such a way that the temperature regulation of the temperature regulating device is improved with a smaller amount of temperature regulating fluid while the packing density of the battery cells (2) remains unchanged, it is proposed that for each battery cell (2) in the group a flow guide surface (8) is provided which is spaced apart from an outer peripheral section (9) of the battery cell (2), which flow guide surface has an entry section (10) and a discharge section (11) which are each essentially parallel to the outer peripheral section (9), and between the entry section (10) and the discharge section (11) there is arranged a diffuser section (12) which is recessed with respect to the entry section (10) and the discharge section (11) and the outer peripheral section (9).

Description

TECHNICAL FIELD

[0001] The present application relates to a temperature regulating device having individual battery cells assembled into modules, which are arranged in a flow channel through which a temperature regulating fluid flows in a main flow direction. BACKGROUND

[0002] Temperature regulating devices are known from the prior art for battery modules of different construction, in which individual battery cells are arranged in a flow channel (DE 102 015 013 377 A1). Here, the temperature regulating fluid flows through the flow channel in a main flow direction from a first fluid connection group to a second fluid connection group. Disadvantageously, however, different flow speeds between the battery cells in the flow channel form, especially in the case of cylindrical battery cells, so that uniform heat exchange between the battery cells and the temperature regulating fluid is impeded. This problem is exacerbated when the battery cells are particularly tightly packed, since even small dead volumes are then sufficient to make high-efficiency flow around the battery cells impossible and thus highly dynamic temperature regulation with a small amount of temperature regulating fluid impossible. However, it is precisely at power peaks, both when charging and when discharging, that it is important for the long service life of the battery cells to operate them in a low temperature range and to allow only low temperature differences within the battery module. SUMMARY

[0003] The technical problem addressed by the present application is therefore to improve the temperature regulation of the temperature regulating device with a small amount of temperature regulating fluid, while the packing density of the battery cells remains the same.

[0004] The present invention solves the technical problem by providing a flow guide surface spaced apart from the outer circumference of the battery cell for each battery cell in the pack. The flow guide surface comprises an inlet section and an outlet section substantially parallel to the outer circumference, and a diffuser section is arranged between the inlet and outlet sections, which is recessed relative to the inlet and outlet sections and the outer circumference. The invention is based on the recognition that the flow around the battery cells known from the prior art only produces a localized and short-term cooling effect, without allowing for a complete heat exchange between the temperature control fluid and the battery cells. Therefore, according to the invention, a flow guide channel for the temperature control fluid is formed between the flow guide surface spaced apart from the battery cell and at least one outer circumference of the battery cell, by uniformly and continuously flowing around the outer circumference of the battery cell. The diffuser section ensures that no stagnation points occur for the temperature control fluid and minimizes pressure losses along the channel. On the other hand, with appropriate arrangement, the flow-guiding surfaces reduce dead volume in the flow channel, enabling more dynamic temperature control. In a particularly preferred embodiment, the temperature-regulating fluid flows directly onto the periphery of the battery cells. This means that the periphery of the battery cells, like the flow-guiding surfaces, is in direct contact with the temperature-regulating fluid.

[0005] Flow simulations have shown that particularly efficient cooling is achieved if the distance between the peripheral section and the diffuser section is 5% to 30% greater than the distance between the peripheral section and the inlet or outlet section. In particular, stagnation points and the associated pressure losses can be sufficiently reduced if the distance between the peripheral section and the diffuser section is 5% to 15% greater than the distance between the peripheral section and the inlet or outlet section. Furthermore, it has been shown that the ratio of distances within the flow channel can also vary. Therefore, it is recommended that the ratio of the distance between the peripheral section and the diffuser section to the distance between the peripheral section and the inlet or outlet section be greater in the edge region of the flow channel than in the center region of the flow channel. In particular, when using cylindrical battery cells, the distance between the peripheral section and the diffuser section can be in the range of 1.25 mm to 2.25 mm, preferably 1.75 mm, while the distance between the peripheral section and the inlet or outlet section can be in the range of 1 mm to 2 mm, preferably 1.6 mm.

[0006] In order to ensure not only the distribution of the fluid flow but also a uniform flow of fluid to the battery cells using the simplest possible structural design measures, it is recommended that the flow-guiding surfaces of adjacent battery cells form a flow divider. This means that the flow divider fills the gaps between adjacent battery cells, excluding the guide channels formed between the flow-guiding surfaces and the battery cells, thereby reducing any dead volume that would otherwise be present. Thus, in the case of cylindrical battery cells, when the individual battery cells are arranged in the most compact circular packaging, a flow divider with an approximately star-shaped cross-section and three radial structures is produced.

[0007] Tests have shown that the ventilation properties of the flow channel can be improved by forming a flow diverter group with an additional flow-guiding surface that extends essentially parallel to the inner wall of the flow channel. In addition to the already described effect of the flow diverter, the amount of air initially present in the flow channel is reduced and discharged more efficiently during ventilation. Venting can be further improved if the distance between the additional flow-guiding surface and the inner wall is greater than the distance between the inlet or outlet sections of the remaining flow-guiding surfaces and the outer circumference of the corresponding adjacent battery cell.

[0008] In order to allow the cooling fluid to be introduced into the guide channel at a uniform flow velocity across the entire flow channel cross section, it is recommended that the flow channel have at least two fluid connections at each of two edge sections lying opposite one another in the main flow direction, with at least one battery cell being arranged between at least two fluid connections in an edge section. This arrangement of multiple fluid connections not only reduces velocity differences transverse to the main flow direction, thereby enabling more uniform heat exchange across all battery cells, but also allows for immediate use of locally higher flow velocities perpendicular to the inflow direction of the temperature control fluid to cool the battery cells held between the at least two fluid connections in the edge section. In this context, "a battery cell is arranged between at least two fluid connections" means that the cross section of the battery cell, extending in the main flow direction, is at least partially located at the level of the fluid connections in the main flow direction. In a particularly preferred embodiment of the temperature control device, the inflow direction of the fluid connections extends perpendicular to the main flow direction in the longitudinal direction of, for example, a cylindrical battery cell.

[0009] By providing a flow guide element between the fluid connection and the two battery cells adjoining the fluid connection and the flow guide element having a flow guide surface which is convexly shaped towards the fluid connection, a more uniform distribution of the temperature regulating fluid can be achieved, especially in the area directly adjoining the fluid connection. The flow guide surface here forms a flow resistance which limits the amount of temperature regulating fluid flowing into the area behind the flow guide element. If, as mentioned above, two fluid connections adjoin on a battery cell, it is proposed to provide a flow guide element according to the application between each fluid connection and the battery cell, so that the volume of temperature regulating fluid flowing in through both fluid connections can be reduced in relation to the battery cell which is only met by one fluid connection.

[0010] In order to avoid turbulence in the inflow area, the fluid connection can have an oval, preferably elliptical, cross section which is flattened in the main flow direction. Thereby, not only the available space of the temperature regulating device which is not available for the battery cell is optimally used, but also a pressure drop along the fluid connection in the main flow direction is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0011] The technical solution of the application is shown exemplarily in the drawings. In the drawings

[0012] Figure 1 a top view of a temperature regulating device according to the application is shown,

[0013] Figure 2 a side view of the temperature regulating device according to the application is shown and

[0014] Figure 3 a detail view is shown on a larger scale Figure 1 . DETAILED DESCRIPTION

[0015] The temperature regulating device according to the application has an opening 1 for accommodating a battery cell 2 in a flow channel 3. The flow channel 3 has two inlet-side fluid connections 4 and two outlet-side fluid connections 5, between which inlet-side and outlet-side fluid connections a main flow direction 6 is formed. A flow divider 7 is arranged in the flow channel 3, which, in a preferred embodiment, extends from the opening 1 to the opening 1 opposite the flow channel 3 transversely to the main flow direction 6 within the flow channel 3.

[0016] As can be seen especially from Figure 3As can be seen, at least one set of flow splitters 7 has flow faces 8 which extend substantially parallel to the peripheral section 9 of the cell 2. These flow faces 8 have an entry section 10 and a discharge section 11 which are arranged at the same distance, i.e. a standard distance, from the peripheral section 9. Between the entry section 10 and the discharge section 11 there is a diffuser section 12 which is arranged at a distance from the peripheral section 9 which is 5% to 30% greater than the distance of the peripheral section 9 from the entry section 10 or the discharge section 11.

[0017] In the edge region of the flow channel 3 there is a further flow splitter 13 which forms a further flow face 15 which extends substantially parallel to the inner wall 14 of the flow channel 3 and which ensures the exhaust performance of the flow channel 2 and optimised flow conditions in the edge region.

[0018] As shown in Figure 3 , the further flow face 15 can also have an entry section 10, a discharge section 11 and a diffuser section 12 which is recessed with respect to the inner wall 14 and which is located therebetween.

[0019] The fluid connections 4, 5 at the opposite edge sections are ensured by their arrangement that more uniform flow characteristics are achieved when the temperature-regulating fluid enters the flow channel 3. The cross-section of the fluid connections 4, 5 is designed as oval and is flat in the main flow direction 6. Thus, on the one hand, the space available is used optimally and, on the other hand, the turbulence in the inflow and outflow regions is minimised. In order to also ensure that uniform flow characteristics are already formed in the region immediately after the fluid connections 4, 5, flow guide elements 16 are provided which have a flow face 17 which is convexly shaped towards the fluid connections 4, 5 as a flow resistance and which act as flow splitters.

Claims

1. Temperature regulating device, having individual battery cells (2) assembled into modules, which are arranged in a flow channel (3) through which a temperature regulating fluid flows in a main flow direction (6), characterized in that, A flow guide surface (8) is provided for each battery cell (2) in the group, spaced apart from the peripheral section (9) of the battery cell (2), the flow guide surface having an entry section (10) and an exit section (11) which are substantially parallel to the peripheral section (9), and a diffuser section (12) which is recessed relative to the entry section (10) and exit section (11) and the peripheral section (9) arranged between the entry section (10) and the exit section (11), wherein the distance between the peripheral section (9) and the diffuser section (12) is 5% to 30% greater than the distance between the peripheral section (9) and the entry section (10) or the exit section (11).

2. The temperature regulating device of claim 1, wherein, The flow guide surfaces (8) of the battery cells (2) which adjoin one another form a flow divider (7).

3. The temperature regulating device of claim 2, wherein, The groups of flow dividers (13) form further flow guide surfaces (15) which extend substantially parallel to the inner wall (14) of the flow channel (2).

4. The temperature regulating device of claim 1, wherein, The flow channel (2) has at least two fluid connections (4, 5) on two edge sections which lie opposite one another in the main flow direction (6), wherein at least one battery cell (2) is arranged between the at least two fluid connections (4, 5) of an edge section.

5. The temperature regulating device of claim 4, wherein, Between a fluid connection (4, 5) and the two battery cells (2) which adjoin the fluid connection (4, 5), a flow guide element (16) is provided, which has a flow guide surface (17) which is convexly shaped towards the fluid connection (4, 5).

6. Temperature regulating device according to claim 4 or 5, characterized in that The fluid connections (4, 5) have an oval, flattened cross section in the main flow direction (6).

Images