Energy storage device

Abstract

To provide an energy storage device capable of effectively cooling battery modules. [Solution] The energy storage device is constructed by stacking a conductive current collector plate, a plurality of battery modules each containing one or more battery cells, and a cooler for cooling the battery modules, and grooves are formed on the surface of the current collector plate facing the battery modules.

Description

Technical Field

[0001] The technology of the present disclosure relates to a power storage device.

Background Art

[0002] In addition to power storage devices for small portable terminals such as mobile phones and laptop computers, in recent years, the demand for power storage devices installed in vehicles such as battery electric vehicles (BEV) and hybrid electric vehicles (HEV) has also been increasing.

[0003] For example, Patent Document 1 below describes a power storage device including a cooler disposed between adjacent power storage modules, a first current collector plate laminated on one side of the power storage module, and a second current collector plate laminated on the other side of the battery module.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Ensuring the cooling of the battery module (power storage module) used in the power storage device is important for maintaining the performance of the power storage device over a long period. And from the perspective of the cooling performance of this power storage device, there is still room for improvement.

[0006] In view of the above problems, an object of the present disclosure is to provide a power storage device capable of effectively cooling a battery module.

Means for Solving the Problems

[0007] To achieve the above objective, the energy storage device according to claim 1 is configured by stacking a conductive current collector plate, a plurality of battery modules including one or more battery cells, and a cooler for cooling the battery modules, and grooves are formed on the surface of the current collector plate facing the battery modules.

[0008] In the energy storage device according to claim 1, the heat generated in the battery module can be dissipated into the groove, thereby improving the cooling performance of the energy storage device.

[0009] The energy storage device according to claim 2 is the energy storage device according to claim 1, wherein at least one end of the groove extends to the outer edge of the current collector plate.

[0010] In the energy storage device of claim 2, the heat released into the groove can be smoothly released to the outside of the current collector plate.

[0011] The energy storage device according to claim 3 is an energy storage device according to claim 1 or claim 2, wherein a plurality of grooves are formed so as to traverse the surface of the current collector plate facing the battery module.

[0012] In the energy storage device of claim 3, the heat released into the groove can be released more smoothly from the current collector plate to the outside.

[0013] The energy storage device according to claim 4 further includes a conductive current-carrying plate disposed between the battery modules, in the energy storage device according to any one of claims 1 to 3.

[0014] In the energy storage device of claim 4, the coolers can be arranged efficiently. [Effects of the Invention]

[0015] The aforementioned energy storage device makes it possible to effectively cool the battery module. [Brief explanation of the drawing]

[0016] [Figure 1]This is an exploded perspective view showing an example of a power storage device according to one embodiment of the present disclosure. [Figure 2] Figure 1 is a perspective view showing an example of a current collector plate included in the energy storage device. [Figure 3] Figure 2 shows an example of the side of the current collector plate facing the battery module. [Figure 4] Figure 1 is a schematic diagram showing a portion of the energy storage device as viewed from the front. [Figure 5] This is a cross-sectional view taken along line AA, as shown in Figure 4. [Modes for carrying out the invention]

[0017] The following describes various embodiments for implementing this disclosure with reference to the drawings. In the following, only the necessary parts for explaining the objectives of this disclosure are schematically shown, and the explanation will primarily focus on the parts necessary for explaining the relevant sections of this disclosure. Any parts omitted from the explanation will be considered to be based on prior art. Furthermore, identical or equivalent components in the drawings are denoted by the same or similar reference numerals, and redundant explanations are omitted. Additionally, if multiple identical or equivalent components are included in the drawings, reference numerals may be assigned to only some of them for clarity.

[0018] Figure 1 is an exploded perspective view showing an example of a battery storage device according to one embodiment of the present disclosure. The battery storage device 1 according to this embodiment is described below as an example of one installed in a vehicle such as a BEV or HEV. In the following description, the direction indicated by arrow X will be the left-right direction, the direction indicated by arrow Y will be the front-back direction, and the direction indicated by arrow Z will be the up-down direction.

[0019] As shown in Figure 1, the energy storage device 1 has an energy storage body 2 that includes at least current collector plates 10A and 10B, a plurality of battery modules 20, and a cooler 30. The energy storage body 2 may be constructed by stacking the battery modules 20 and the cooler 30 so that the cooler 30 is positioned between the battery modules 20, and then sandwiching the stacked battery modules 20 and the cooler 30 between a pair of current collector plates 10A and 10B.

[0020] The current collector plates 10A and 10B may include two current collector plates 10A and 10B each formed of a plate body made of a conductive material. Among these, one current collector plate (hereinafter, this current collector plate is referred to as the "first current collector plate") 10A may be laminated on the upper part of the battery module 20A (hereinafter, this battery module may be referred to as the "first battery module") located at the uppermost position in the stacking direction of the battery module 20, for example, the vertical direction. Further, the other current collector plate (hereinafter, this current collector plate is referred to as the "second current collector plate") 10B may be laminated on the lower part of the battery module 20B (hereinafter, this battery module may be referred to as the "second battery module") located at the lowermost position in the vertical direction. The first current collector plate 10A may be, for example, a current collector plate for a positive electrode, and the second current collector plate 10B may be, for example, a current collector plate for a negative electrode. In this regard, the first current collector plate 10A may be connected to the positive electrode terminal 11A (see FIG. 2), and the second current collector plate 10B may be connected to the negative electrode terminal 11B (see FIG. 2).

[0021] A plurality of battery modules 20 are arranged in a predetermined first direction, for example, the vertical direction. The plurality of battery modules 20 can be configured, for example, as secondary batteries having a substantially rectangular parallelepiped appearance, and may have a plurality of battery cells 21 (see FIG. 4) inside. The battery module 20 of the present embodiment can be configured as a so-called bipolar battery. More specifically, the battery module 20 can be configured, for example, as a laminated aqueous lithium ion battery or a nickel hydrogen battery. Note that the battery module 20 is not limited to the above-described bipolar battery, and may be, for example, an all-solid-state battery or a capacitor.

[0022] The cooler 30 can be made of a roughly plate-shaped member whose left-right and front-back dimensions are adjusted to be approximately the same as those of the battery module 20, and is placed between adjacent battery modules 20. The cooler 30 can be made of a material with high thermal conductivity, and may have a refrigerant flow path (not shown) inside through which the refrigerant can flow. The specific cooling structure of the cooler 30 is not limited to those described above, and various types can be used as long as they provide a cooling function.

[0023] The energy storage unit 2 does not necessarily have a cooler 30 installed in the entire space between the two battery modules 20. Specifically, in the energy storage unit 2 of this embodiment, a current-carrying plate 35 may be installed in place of the cooler 30 between the two battery modules 20 located in the middle of its vertical direction.

[0024] The conductive plate 35 can be made of a conductive plate that can electrically connect adjacent battery modules 20. Furthermore, it is preferable to use a material with high thermal conductivity for the conductive plate 35 so that the cooling effect of the cooler 30 is not hindered by the conductive plate 35. By using this conductive plate 35 in appropriate places, the number of coolers 30 used in a single energy storage device 1 can be adjusted, thereby reducing the manufacturing cost of the energy storage device 1. It is also possible to install coolers 30 instead of the conductive plate 35, and the conductive plate 35 can be omitted.

[0025] The energy storage body 2, including the configuration described above, may be housed in a case 40. The case 40 may include at least a top plate 41 and a bottom plate 42.

[0026] The upper plate 41 may cover the upper part of the first current collector plate 10A. The bottom plate 42 may cover the bottom of the second current collector plate 10B. Side walls covering the sides of the energy storage body 2 may be erected around the outer perimeter of the bottom plate 42. Furthermore, insulating sheets and elastic sheets (not shown) may be interposed between the upper plate 41 and the first current collector plate 10, and between the bottom plate 42 and the second current collector plate 10B, respectively.

[0027] In this configuration, the first battery module 20A and the second battery module 20B of the aforementioned energy storage body 2 have a cooler 30 installed on only one side, while the first or second current collector plates 10A and 10B are installed on the other side. In this case, since there is no cooler 30 on the other side of the first battery module 20A and the second battery module 20B, the cooling function of the battery module 20 is reduced compared to the side with the cooler 30. As a result, a temperature difference may occur between a battery cell 21 adjacent to one side of the first and second battery modules 20A and 20B (specifically, the first battery cell 21A, etc., described later) and a battery cell 21 adjacent to the other side (specifically, the second battery cell 21B, etc., described later). When such a temperature difference occurs, the deterioration of some battery cells that are not adequately cooled progresses more rapidly than that of other battery cells, and the service life of the battery module 20 or the entire energy storage device 1 may be shorter than when the aforementioned temperature difference does not occur. Therefore, in this embodiment, in order to suppress the temperature difference mentioned above and prevent the occurrence of partial cooling failure of the battery module 20, the current collector plates 10A and 10B are given a structure that improves their cooling performance. The structure of the current collector plates 10A and 10B will be described in more detail below.

[0028] Figure 2 is a perspective view showing an example of a current collector plate included in the energy storage device shown in Figure 1. Figure 3 is a schematic diagram showing an example of the surface of the current collector plate shown in Figure 2 that faces the battery module. Note that the current collector plates 10A and 10B included in this embodiment may have the same configuration except for their arrangement and polarity. Therefore, in Figures 2 and 3, the first current collector plate 10A is described illustratively, and the reference numerals corresponding to the second current collector plate 10B are shown in parentheses, and the description is reused.

[0029] As shown in Figure 2, the first current collector plate 10A of the energy storage device 1 according to this embodiment is made of a plate-shaped conductor and has a positive electrode terminal 11A at one end. A groove 13A is provided on the surface 12A of the first current collector plate 10A that faces the battery module 20, or more specifically, the surface (hereinafter referred to as the "module-facing surface") facing the first battery module 20A.

[0030] The groove 13A constitutes a passage capable of receiving heat released from the upper part of the first battery module 20A towards the first current collector plate 10A. Furthermore, it is preferable that at least one end of the groove 13A extends to the outer edge of the first current collector plate 10A so that heat from the first battery module 20A can be released to the outside of the first current collector plate 10A. The number, width, and direction of extension of the groove 13A can be adjusted as appropriate within the range that maintains the functions described above. In this embodiment, as shown in Figure 3, a first current collector plate 10A is provided with a plurality (for example, 5) of grooves 13A that extend linearly along the front-rear direction from its front end to its rear end, traversing the module-facing surface 12A, and are provided substantially parallel to each other. Configuring the groove 13A as described above is preferable because it allows heat received from the first battery module 20A to be smoothly released to the outside of the first current collector plate 10A from both ends. Furthermore, the groove 13A only needs to be capable of receiving heat, and its end does not need to reach the outer edge of the first current collector plate 10A, as in the example described above. Also, the cross-sectional shape of the groove 13A is not particularly limited, and a roughly triangular, square, trapezoidal, or semicircular shape can be used as appropriate. Figure 4 shows an example of a groove 13B with a roughly triangular cross-section.

[0031] Furthermore, the position where the groove 13A is provided should be such that it does not overlap with the adhesive application area 14 where adhesive is applied to bond the first current collector plate 10A to the first battery module 20A, as shown in Figure 3. By arranging the groove 13A and the adhesive application area 14 so as not to overlap, it is possible to prevent adhesive from flowing into the groove 13A and partially blocking it. For example, as shown in Figure 3, if the extending direction of the groove 13A and the extending direction of the adhesive application area 14 are substantially aligned, the bonding between the first current collector plate 10A and the first battery module 20A can be reliably achieved, and the heat dissipation function of the groove 13A can be ensured. It is preferable to use a conductive adhesive for the adhesive applied to the adhesive application area 14.

[0032] Figure 4 is a schematic diagram of a part of the energy storage body shown in Figure 1, viewed from the front. In Figure 4, only the second current collector plate 10B, the second battery module 20B, and the cooler 30 located on top of the second battery module 20B are shown in an enlarged view. The second battery module 20B shown in Figure 4 is composed of multiple, for example, 30, plate-shaped battery cells 21 stacked on top of each other. In this second battery module 20B, if the groove 13B is not provided in the second current collector plate 10B, the battery cells 21B adjacent to the second current collector plate 10B (hereinafter referred to as "second battery cells") 21B and the surrounding battery cells 21 will not be cooled as well as other battery cells, for example, the battery cells 21A adjacent to the cooler 30 (hereinafter referred to as "first battery cells") 21A and the surrounding battery cells 21. Therefore, a large temperature difference may occur among the 30 battery cells 21. Therefore, in this embodiment, by forming multiple grooves 13B on the module-facing surface 12B of the second current collector plate 10B, the cooling performance of the second battery cell 21B and the surrounding battery cells 21 is improved, and the occurrence of temperature differences between the battery cells 21 within the second battery module 20B is suppressed.

[0033] Figure 5 is a cross-sectional view taken along line AA shown in Figure 4. When charging and discharging of the energy storage body 2 in this embodiment begins, heat is generated from each battery cell 21 in the second battery module 20B. At this time, the heat generated in the first battery cell 21A, etc., adjacent to the cooler 30, is dissipated through the cooler 30. On the other hand, the heat 50 generated in the second battery cell 21B, etc., adjacent to the second current collector plate 10B, is released to the outside of the energy storage body 2 through the groove 13B formed in the second current collector plate 10B, as shown in Figure 5. By adopting a configuration that allows the heat 50 released from the battery cell 21 adjacent to the second current collector plate 10B, such as the second battery cell 21B, to be released to the outside through the groove 13B, poor cooling of the second battery cell 21B, etc., can be suppressed. As a result, temperature differences between the battery cells 21 become less likely to occur.

[0034] As described above, the energy storage device of this embodiment makes it possible to effectively cool the multiple battery modules included in the energy storage device, thereby suppressing adverse effects on the lifespan of the battery modules or the energy storage device due to the progression of partial battery cell degradation.

[0035] This disclosure is not limited to the embodiments described above, and can be implemented with various modifications without departing from the spirit of this disclosure. All such modifications are included in the technical concept of this disclosure. Furthermore, unless otherwise specified in the specification, each component of this disclosure is not limited to one, but may exist in multiple forms. [Explanation of Symbols]

[0036] 1. Energy storage device 10A, 10B current collector plate 12A, 12B module opposing surfaces 13A, 13B groove 20 Battery Modules 20A First Battery Module 20B Second Battery Module 21 battery cells 30 Cooler 35 Electrical plate

Claims

1. The device is constructed by stacking a conductive current collector plate, a plurality of battery modules containing one or more battery cells, and a cooler for cooling the battery modules, and grooves are formed on the surface of the current collector plate facing the battery modules. Energy storage device.

2. The groove extends at least one end to the outer edge of the current collector plate. The energy storage device according to claim 1.

3. Multiple grooves are formed so as to traverse the surface of the current collector plate facing the battery module. The energy storage device according to claim 1.

4. The battery modules further include conductive current-carrying plates arranged between them. The energy storage device according to claim 1.

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