ENERGY STORAGE DEVICE

Abstract

An energy storage device is configured by stacking an electrically conductive current collector plate, a plurality of battery modules, each containing one or more battery cells, and a heat sink for cooling the battery modules. A groove is provided on a surface of the current collector plate facing the battery module.

Description

BACKGROUND OF THE INVENTION 1. Field of the invention

[0001] The technology described in the present disclosure relates to energy storage devices. 2. Description of the state of the art

[0002] Energy storage devices are not only used in small portable devices such as mobile phones and laptops, but have also recently been increasingly used in vehicles such as battery electric vehicles (BEVs) and hybrid electric vehicles (HEVs).

[0003] For example, Japanese unpublished patent application No. 2023-177537 (JP 2023-177537 A) discloses an energy storage device comprising: a cooler arranged between adjacent energy storage modules; a first current collector plate layered on one side of the energy storage modules; and a second current collector plate layered on the other side of the battery modules. OVERVIEW OF THE INVENTION

[0004] Reliable cooling of battery modules (energy storage modules) used in an energy storage device helps to maintain the performance of the energy storage device over a longer period. However, there is still room for improvement regarding the cooling performance of such energy storage devices.

[0005] The present disclosure was made taking into account the problems described above, and its aim is to provide an energy storage device that can effectively cool battery modules.

[0006] To achieve the aforementioned objective, an energy storage device according to claim 1 is configured by stacking an electrically conductive current collector plate, a plurality of battery modules, each comprising one or more battery cells, and a cooler configured for cooling the battery modules. A groove is provided on a surface of the current collector plate facing the battery module.

[0007] In the energy storage device according to claim 1, the heat generated in the battery modules can be transferred to the slots, thereby improving the cooling performance of the energy storage device.

[0008] According to an energy storage device according to claim 2, in the energy storage device according to claim 1 at least one end of the groove extends to an outer edge of the current collection plate.

[0009] In the energy storage device according to claim 2, the heat released into the groove can be smoothly transferred to the outside of the current collector plate.

[0010] According to an energy storage device according to claim 3, in the energy storage device according to claim 1 or 2, a plurality of grooves are provided such that they extend over the surface of the current collection plate facing the battery module.

[0011] In the energy storage device according to claim 3, the heat released into the groove can be better transferred to the outside of the current collection plate.

[0012] According to an energy storage device as claimed in claim 4, the energy storage device as claimed in any one of claims 1 to 3 further comprises an electrically conductive electrical connection plate. The electrical connection plate is arranged between the battery modules.

[0013] In the energy storage device according to claim 4, the cooler can be arranged efficiently.

[0014] According to the energy storage device described above, the battery modules can be cooled efficiently. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Features, advantages and technical and industrial significance of exemplary embodiments of the invention are described below with reference to the accompanying drawings, in which the same symbols denote the same elements, wherein: Fig. Figure 1 is an exploded view showing an example of an energy storage device according to an embodiment of the present disclosure; Fig. 2 is a perspective view showing an example of a power busbar located in the Fig. The energy storage device shown in section 1 is included; Fig. 3. An example of a surface of the current collector plate in Fig. 2 shows the one opposite a battery module; Fig. 4 a schematic front view of a section of an energy storage unit made of Fig. 1 shows; and Fig. 5 is a section along line AA in Fig. 4. DETAILED DESCRIPTION OF THE EXECUTION FORMS

[0016] Embodiments for carrying out the present disclosure are described below with reference to the drawings. The following description schematically represents the scope necessary to achieve the objectives of the present disclosure and focuses primarily on the relevant sections required for the explanation, while descriptions of sections based on known techniques are omitted. Identical or corresponding components in the drawings are indicated by the same or similar symbols, and redundant descriptions are omitted. If several identical or corresponding components are included in the drawings, only some of them may be indicated by symbols for the sake of simplicity.

[0017] Fig. Figure 1 is an exploded view showing an example of an energy storage device according to an embodiment of the present disclosure. An energy storage device 1 according to the present embodiment is illustrated below as an energy storage device mounted in a vehicle, for example, a battery electric vehicle (BEV) or a hybrid electric vehicle (HEV). In the following description, the direction indicated by arrow X is defined as the left-right direction, arrow Y as the front-back direction, and arrow Z as the up-down direction.

[0018] As in Fig. As shown in Figure 1, the energy storage device 1 comprises at least one energy storage unit 2, which includes a pair of current collector plates 10A, 10B, a plurality of battery modules 20, and a cooler 30. The energy storage unit 2 can be formed by stacking the battery modules 20 and the cooler 30, with the cooler 30 arranged between the battery modules 20, and then the resulting stack sandwiched between the current collector plates 10A, 10B.

[0019] The current collector plates 10A, 10B can comprise two current collector plates 10A, 10B configured as plate-shaped elements made of an electrically conductive material. Of the current collector plates 10A, 10B, one current collector plate (hereinafter referred to as the "first current collector plate") 10A can be stacked on top of the uppermost battery module 20A in the same layering direction as the battery modules 20 (e.g., up-down) (hereinafter this battery module can be referred to as the "first battery module"). The other current collector plate (hereinafter referred to as the "second current collector plate") 10B can be stacked upwards on the underside of the lowermost battery module 20B (hereinafter this battery module can be referred to as the "second battery module"). For example, the first current collector plate 10A can be a current collector plate for a cathode, and the second current collector plate 10B can be a current collector plate for an anode.In this context, the first current collector plate can be rated 10A with a cathode connection of 11A (see . Fig. 2) be connected, and the second current collector plate 10B can be connected to an anode terminal 11B (see Fig. 2) be connected.

[0020] The battery modules 20 are arranged in a predetermined first direction, for example, the up-down direction. The battery modules 20 can be configured as secondary batteries with a substantially rectangular parallelepiped shape and each contain a plurality of battery cells 21 (see Fig. 4) include. The battery modules 20 of the present embodiment can be configured as so-called bipolar batteries. More specifically, the battery modules 20 can be, for example, laminate lithium-ion batteries or nickel-metal hydride batteries. The battery modules 20 are not limited to bipolar batteries and can, for example, be solid-state batteries or capacitors.

[0021] The cooler 30 can be configured as an essentially plate-shaped element whose dimensions in the left-right and front-back directions are adapted to approximately match those of the battery module 20. The cooler 30 is arranged between adjacent battery modules 20. The cooler 30 can be made of a material with high thermal conductivity and can be provided with an internal coolant channel (not shown) through which a coolant can flow. The specific cooling structure of the cooler 30 is not limited to the example described above, and any configuration can be adopted as long as it provides a cooling function.

[0022] A cooler 30 need not be provided between each pair of adjacent battery modules 20 in the energy storage unit 2. In particular, in the energy storage unit 2 of the present embodiment, an electrical connection plate 35 can be arranged between two battery modules 20 that are arranged in the middle in an upward-downward direction, instead of a cooler 30.

[0023] The electrical connection plate 35 can be configured as an electrically conductive, plate-shaped element that can electrically connect adjacent battery modules 20. It is advantageous to use a material with high thermal conductivity for the electrical connection plate 35, as such a material will not impair the cooling effect provided by the cooler 30. By appropriately positioning the electrical connection plate 35, the number of coolers 30 used in a single energy storage device 1 can be adjusted, thereby reducing the manufacturing costs of the energy storage device 1. A cooler 30 can be arranged instead of the electrical connection plate 35, or the electrical connection plate 35 can be omitted.

[0024] The energy storage unit 2, comprising the configuration described above, can be housed in a casing 40. The casing 40 can comprise at least one upper plate 41 and one lower plate 42.

[0025] The top plate 41 can cover the upper surface of the first power collection plate 10A. The bottom plate 42 can cover the underside of the second power collection plate 10B. A side wall covering the side surfaces of the energy storage unit 2 can be provided to extend along the outer circumference of the bottom plate 42. An insulating film and an elastic film (both not shown) can further be arranged between the top plate 41 and the first power collection plate 10A and between the bottom plate 42 and the second power collection plate 10B, respectively.

[0026] In the energy storage unit 2, each of the first battery modules 20A and the second battery modules 20B is configured such that the cooler 30 is located on one surface and the first or second power collection plate 10A, 10B is located on the other surface. Since, in this case, the cooler 30 is not located on the other surface of the first and second battery modules 20A, 20B, its cooling function is less effective on the other surface than on the surface where the cooler 30 is located. Consequently, a temperature difference can occur in each of the first and second battery modules 20A, 20B between the battery cells 21 adjacent to one surface (in particular, a first battery cell 21A, described later, etc.) and the battery cells 21 adjacent to the other surface (in particular, a second battery cell 21B, described later, etc.).When such a temperature difference occurs, some insufficiently cooled battery cells may degrade faster than other cells. This can shorten the service life of the battery module 20 or the entire energy storage device 1 compared to a case where such a temperature difference does not occur. To reduce such a temperature difference and suppress uneven cooling of the battery modules 20, the present embodiment includes a structure for improving the cooling performance of the current collector plates 10A, 10B. The structure of the current collector plates 10A, 10B is described in more detail below.

[0027] Fig. 2 is a perspective view showing an example of a power busbar located in the Fig. The energy storage device shown in section 1 is included. Fig. Figure 3 schematically shows an example of a surface of the current collector plate in Fig. 2, which is opposite a battery module. The current collector plates 10A, 10B in the present embodiment can have the same configuration except for their arrangement and polarity. Therefore, the first current collector plate 10A is identified based on the Fig. 2 and Fig. Figure 3 is described by way of example. Reference symbols corresponding to the second current collector plate 10B are indicated in parentheses in these figures, and essentially the same description applies to the second current collector plate 10B.

[0028] As in Fig. As shown in Figure 2, the first current collector plate 10A of the energy storage device 1 according to the present embodiment is configured as a plate-shaped electrically conductive element, and the cathode terminal 11A is provided at one end of the first current collector plate 10A. A surface of the first current collector plate 10A that faces the battery module 20, more precisely the first battery module 20A (hereinafter referred to as the “module-facing surface” 12A), is provided with a groove 13A.

[0029] The groove 13A forms a passage that can absorb heat dissipated from the upper section of the first battery module 20A towards the first current collector plate 10A. Preferably, at least one end of the groove 13A extends to the outer edge of the first current collector plate 10A to allow heat absorbed by the first battery module 20A to be dissipated to the outer surface of the first current collector plate 10A. The number of grooves 13A and their width and direction of extension can be adjusted accordingly, as long as the function described above is maintained. As in Fig. As shown in Figure 3, in the present embodiment the first current collector plate 10A is provided with a plurality (e.g., five) of substantially parallel grooves 13A, extending linearly in the front-to-back direction across the module-opposite surface 12A from the front end to the rear end of the module-opposite surface 12A. It is preferable to configure the grooves 13A in the manner described above, as this allows the heat absorbed by the first battery module 20A to be dissipated from both ends of the grooves 13A to the outside of the first current collector plate 10A. The grooves 13A can have any configuration as long as they are capable of absorbing heat. The ends of the grooves 13A need not necessarily extend to the outer edge of the first current collector plate 10A, as in the example above.Furthermore, the cross-sectional shape of the grooves 13A is not particularly restricted and can, for example, be essentially triangular, rectangular, trapezoidal, or semicircular. Fig. Figure 4 shows, by way of example, groove 13B with an essentially triangular cross-section.

[0030] As in Fig. As shown in Figure 3, it is advantageous that the slots 13A are positioned such that they do not overlap an adhesive application area 14 onto which an adhesive is applied to connect the first power busbar 10A to the first battery module 20A. Since the slots 13A are arranged so that they do not overlap the adhesive application area 14, it is less likely that the adhesive will flow into the slots 13A and partially clog them. For example, as shown in Figure 3, this ensures that the adhesive will not flow into the slots 13A and partially clog them. Fig. Figure 3 shows that an essentially aligned orientation of the extending direction of the grooves 13A with that of the adhesive application area 14 ensures a reliable connection between the first current collector plate 10A and the first battery module 20A, while furthermore maintaining the heat dissipation function of the grooves 13A. Preferably, an electrically conductive adhesive is used as the adhesive applied to the adhesive application area 14.

[0031] Fig. 4 is a schematic front view of a section of the in Fig. 1 energy storage unit shown. Fig. Figure 4 shows a part of the energy storage unit 2. In particular, only the second power collection plate 10B, the second battery module 20B, and the cooler 30, which is located on the top of the second battery module 20B, are shown in an enlarged view. The in Fig. The second battery module 20B shown in Figure 4 is configured, for example, by layers of a plurality (e.g., 30) of plate-shaped battery cells 21. If no grooves 13B are provided in the second power collection plate 10B of the second battery module 20B, the battery cell (second battery cell) 21B, which is located adjacent to the second power collection plate 10B, and the battery cells 21 surrounding it, will tend to be cooled less effectively than the other battery cells, for example, the battery cell (first battery cell) 21A, which is located adjacent to the cooler 30, and the cells 21 surrounding it. As a result, a significant temperature difference can occur between the thirty battery cells 21.Therefore, in the present embodiment, a plurality of grooves 13B are formed in a module-opposite surface 12B of the second current collection plate 10B in order to improve the cooling performance for the second battery cell 21B and the surrounding battery cells 21, thereby reducing the occurrence of temperature differences between the battery cells 21 within the second battery module 20B.

[0032] Fig. 5 is a section along line AA in Fig. 4. When the charging or discharging of the energy storage unit 2 of the present embodiment begins, heat is generated by each battery cell 21 within the second battery module 20B. At this time, the heat generated by the battery cells 21 adjacent to the cooler 30, such as the first battery cell 21A, is dissipated via the cooler 30. On the other hand, as described in Fig.Figure 5 shows that the heat 50 generated in the battery cells 21 adjacent to the second power collection plate 10B, for example in the second battery cell 21B, is dissipated to the outside of the energy storage unit 2 through the nuts 13B formed in the second power collection plate 10B. By using a configuration that allows the heat 50 dissipated by the battery cells 21 adjacent to the second power collection plate 10B, including the second battery cell 21B, to be dissipated to the outside via the nuts 13B, insufficient cooling of the second battery cells 21B can be reduced. This makes it less likely that temperature differences will occur between the battery cells 21.

[0033] As described above, in the energy storage device of the present embodiment the battery modules contained in the energy storage device can be effectively cooled, thereby reducing adverse effects on the service life of the battery modules or the energy storage device due to progressive local degradation of the battery cells.

[0034] The present disclosure is not limited to the embodiment described above, and various modifications may be made without departing from the spirit and scope of the present disclosure. All such modifications are covered by the technical scope of the present disclosure. For each component of the present disclosure, the number of components is not limited to one, and two or more components may be present unless otherwise specified in the description. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2023-177537

[0003] JP 2023-177537 A

[0003]

Claims

Energy storage device, wherein the energy storage device is configured by stacking an electrically conductive current collector plate, a plurality of battery modules, each comprising one or more battery cells, and a cooler configured to cool the battery modules, and wherein a groove is provided on a surface of the current collector plate facing the battery module. Energy storage device according to claim 1, wherein at least one end of the groove extends to an outer edge of the current collection plate. Energy storage device according to claim 1, wherein a plurality of grooves are provided such that they extend over the surface of the current collection plate facing the battery module. Energy storage device according to claim 1, which further comprises an electrical connection plate which is electrically conductive, wherein the electrical connection plate is arranged between the battery modules.

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