JP2024103234A - Energy storage device and energy storage module - Google Patents

Abstract

To provide a power storage module that can effectively regulate (cool or heat) the temperature of a power storage device.SOLUTION: A power storage module 500 includes a plurality of power storage devices 100 and a temperature adjustment unit 400. The power storage device 100 includes an electrode assembly 20 including a positive electrode 22 and a negative electrode 24, an electrolyte, and a case 10 that accommodates the electrode assembly 20 and the electrolyte. The case 10 includes a first wall having an outer surface on which a recess 12d is provided. The temperature adjustment unit 400 is disposed so as to face the outer surface of the first wall. A stacking end surface 20a of the electrode assembly 20 is disposed so as to face the inner surface of the first wall.SELECTED DRAWING: Figure 6D

Description

The present invention relates to an energy storage device and an energy storage module.

JP 2021-089812 A discloses a battery module including a secondary battery, a cooler, and a heat-conducting member disposed between the secondary battery and the cooler. A groove recessed toward the inside of the case is formed in the wall of the case of the secondary battery facing the cooler. The heat-conducting member fills the space between the facing wall, including inside the groove, and the cooler. This configuration is said to be able to both suppress deformation of the case and suppress deterioration of cooling performance.

JP 2021-089812 A

However, in a power storage module (e.g., a battery pack) that includes multiple power storage devices (e.g., secondary batteries), when a large current is continuously charged or discharged, or when some abnormality (such as an internal short circuit) occurs, the individual power storage devices may become hot. In addition, the higher the capacity of the power storage device, the smaller the cooling effect of natural heat dissipation or the temperature adjustment mechanism becomes.

Therefore, the main objective of this disclosure is to provide an energy storage module that can effectively regulate the temperature (cooling or heating) of an energy storage device.

The energy storage module disclosed herein includes a plurality of energy storage devices and a temperature adjustment unit. The energy storage device includes an electrode body including a positive electrode and a negative electrode, an electrolyte, and a case that contains the electrode body and the electrolyte. The case includes a first wall having an outer surface with a recess, and the temperature adjustment unit is disposed so as to face the outer surface of the first wall, and the stacked end surface of the electrode body is disposed so as to face the inner surface of the first wall.

According to this configuration, by providing a recess on the outer surface of the first wall of the electricity storage device, the surface area of the outer surface of the first wall is increased, and the heat exchange efficiency with the temperature adjustment unit arranged opposite the outer surface is improved. This makes it possible to effectively adjust the temperature (cooling or heating) of the electricity storage device. In addition, by arranging the stacking end surface of the electrode body in a direction facing the inner surface of the first wall, the electrode body becomes more susceptible to the effect of cooling or heating from the temperature adjustment unit, and the temperature of the electrode body can be effectively adjusted.

1 is an exploded perspective view illustrating a power storage module according to an embodiment of the present invention; 1 is a vertical cross-sectional view illustrating a schematic configuration of an electricity storage device according to an embodiment. 1 is a cross-sectional view illustrating a schematic configuration of an electricity storage device according to an embodiment. FIG. 3 is a schematic vertical cross-sectional view taken along line IV-IV in FIG. 2 . FIG. 2 is a schematic diagram showing the configuration of an electrode body according to one embodiment. 5 is a plan view illustrating a schematic arrangement pattern of recesses in a bottom wall of a case of an electricity storage device according to one embodiment. FIG. 5 is a plan view illustrating a schematic shape of a recess in a bottom wall of a case of an electricity storage device according to one embodiment. FIG. 5 is a cross-sectional view illustrating a schematic shape of a recess in a bottom wall of a case of an electricity storage device according to one embodiment. FIG. 4 is a schematic diagram showing an arrangement of a bottom wall of a case of an electricity storage device according to an embodiment and a temperature adjustment unit. FIG. 13 is a plan view showing a schematic arrangement pattern of recesses in a bottom wall of a case of an electricity storage device in Modification 1. FIG. 13 is a plan view illustrating a schematic shape of a recess in a bottom wall of a case of an electricity storage device in Modification 1. FIG. 13 is a cross-sectional view illustrating a schematic shape of a recess in a bottom wall of a case of an electricity storage device according to Modification 1. FIG. 13 is a plan view showing a schematic arrangement pattern of recesses in a bottom wall of a case of an electricity storage device in Modification 2. FIG. 13 is a plan view illustrating a schematic shape of a recess in a bottom wall of a case of an electricity storage device in Modification 2. FIG. 13 is a cross-sectional view illustrating a schematic shape of a recess in a bottom wall of a case of an electricity storage device according to Modification 2. FIG.

Some preferred embodiments of the technology disclosed herein will be described below with reference to the drawings. Note that matters other than those specifically mentioned in this specification and necessary for implementing the technology disclosed herein (for example, the general configuration and manufacturing process of an electricity storage device that does not characterize the technology disclosed herein) can be understood as design matters of a person skilled in the art based on the conventional technology in the field. The technology disclosed herein can be implemented based on the contents disclosed in this specification and the technical common sense in the field. Note that the expression "A to B (where A and B are any numerical value)" indicating a range in this specification means "A or more and B or less", and also includes the meanings of "more than A and less than B", "more than A and B or less", and "A or more and less than B".

In this specification, the term "energy storage device" refers to a device that can be charged and discharged. Energy storage devices include batteries such as primary batteries and secondary batteries (e.g., lithium ion secondary batteries and nickel-metal hydride batteries), and capacitors (physical batteries) such as electric double-layer capacitors.

1 is an exploded perspective view showing a typical example of a storage module 500 according to an embodiment. FIG. 2 is a vertical cross-sectional view showing a typical configuration of a storage device 100. The electrode body 20 in FIG. 2 is shown partially broken for the purpose of explanation. FIG. 3 is a cross-sectional view showing a typical configuration of the storage device 100. FIG. 4 is a schematic vertical cross-sectional view taken along line IV-IV in FIG. 2. FIG. 5 is a schematic view showing a typical configuration of the electrode body 20. In the following description, the symbols L, R, F, Rr, U, and D in the drawings represent left, right, front, rear, top, and bottom. Also, the symbol X in the drawings indicates the short side direction (thickness direction) of the storage device 100, the symbol Y indicates the long side direction of the storage device 100 perpendicular to the short side direction, and the symbol Z indicates the up-down direction of the storage device 100. The short side direction X is also the arrangement direction of the storage device 100. However, these directions are merely for the convenience of explanation and do not limit the installation form of the energy storage device 100 and the energy storage module 500 in any way.

Here, the energy storage module 500 includes a plurality of energy storage devices 100, a plurality of spacers 200, a restraining mechanism 300, and a temperature adjustment unit 400. The energy storage module 500 includes a plurality of energy storage devices 100 arranged along a predetermined direction. Specifically, the adjacent energy storage devices 100 are arranged so that their surfaces in the thickness direction X face each other. That is, here, the plurality of energy storage devices 100 are arranged (stacked) along the thickness direction X. Although not shown, the plurality of energy storage devices 100 may be electrically connected by a conductive member such as a bus bar. The bus bar is electrically connected to the positive terminal member or the negative terminal member of each energy storage device. In this case, the bus bar may connect the plurality of energy storage devices 100 in series, parallel, or multiple series and multiple parallel.

In the energy storage module 500, a spacer 200 is disposed between adjacent energy storage devices 100. The spacer 200 can contribute to equalizing the restraining pressure on the opposing surfaces of adjacent energy storage devices 100. The spacer 200 can be made of, for example, a resin material. Examples of the resin material include natural rubber, synthetic rubber, silicone resin, and urethane resin. Note that the spacer 200 is not a required component.

The restraining mechanism 300 is configured to apply a specified restraining pressure to the multiple energy storage devices 100 and the multiple spacers 200 from the arrangement direction X. Here, the restraining mechanism 300 includes a pair of end plates 310, a pair of side plates 320, and multiple screws 330. The pair of end plates 310 are aligned in a predetermined arrangement direction X. The pair of end plates 310 are arranged at both ends of the energy storage module 500 in the arrangement direction X. The energy storage device 100 is arranged between the pair of end plates 310 along the arrangement direction X. The pair of end plates 310 sandwich the multiple energy storage devices 100 and the multiple spacers 200 in the arrangement direction X.

The pair of side plates 320 bridge the pair of end plates 310. The pair of side plates 320 are fixed to the end plates 310 by a plurality of screws 330 so that the restraining load is, for example, approximately 10 to 15 kN. As a result, a restraining load is applied to the plurality of energy storage devices 100 and the plurality of spacers 200 from the arrangement direction X, and the energy storage module 500 is held integrally. However, the restraining mechanism is not limited to this. The restraining mechanism 300 may include, for example, a plurality of restraining bands or bind bars instead of the side plates 320. Note that the restraining mechanism 300 is not a required configuration.

As shown in FIG. 2, the power storage device 100 includes a case 10, an electrode body 20, and an electrolyte (not shown). Here, the power storage device 100 may include a positive terminal 30, a negative terminal 40, a positive current collecting member 50, an external positive current collecting member 52, a negative current collecting member 60, an external negative current collecting member 62, a gasket 92, and an internal insulating member 94. Here, the power storage device 100 is a lithium ion secondary battery.

The case 10 is a housing that contains the electrode body 20 and the electrolyte. The case 10 may be a box-shaped shape with a bottom including a first wall. The first wall is a wall that faces the temperature adjustment unit 400 in the storage module 500. The case 10 preferably has a flat, bottomed rectangular parallelepiped (angular) outer shape. However, the case 10 is not limited to this and may be cylindrical, rectangular prism, etc. The material of the case 10 may be the same as that conventionally used and is not particularly limited. The case 10 is preferably made of metal, and more preferably made of, for example, aluminum, an aluminum alloy, iron, an iron alloy, etc.

As shown in FIG. 2, the case 10 includes an exterior body 12 having an opening 12h, and a sealing plate (lid) 14 that seals the opening 12h. The case 10 preferably includes the exterior body 12 and the sealing plate 14. The exterior body 12 and the sealing plate 14 have sizes according to the size of the electrode body 20, the number of electrodes to be accommodated (one or more; here, more than one), etc.

The exterior body 12 is a bottomed, rectangular container having an opening 12h on the upper surface. The exterior body 12 has a substantially rectangular bottom wall 12a, a pair of first side walls 12b (see FIG. 3) extending from the long side of the bottom wall 12a and facing each other, and a pair of second side walls 12c (see FIGS. 2 and 3) extending from the short side of the bottom wall 12a and facing each other. The bottom wall 12a faces the opening 12h (see FIG. 2). Here, the first side wall 12b has a larger area than the second side wall 12c. In this embodiment, the bottom wall 12a is the first wall described above. Therefore, in this embodiment, the present technology can be understood by reading the "bottom wall 12a" as the "first wall". In the energy storage module 500, the energy storage device 100 is arranged so that the bottom wall 12a faces the temperature adjustment unit. However, the first wall is not limited to the bottom wall 12a, but may be the first side wall 12b, the second side wall 12c, or the sealing plate 14.

The sealing plate 14 is a plate-like member attached to the exterior body 12 so as to close the opening 12h of the exterior body 12. The sealing plate 14 faces the bottom wall 12a of the exterior body 12. The sealing plate 14 is substantially rectangular. The case 10 is integrated by joining (e.g., welding) the sealing plate 14 to the periphery of the opening 12h of the exterior body 12. This makes the case 10 airtightly sealed (sealed).

As shown in FIG. 2, the sealing plate 14 is provided with a liquid inlet 15, a gas exhaust valve 17, and terminal outlet holes 18 and 19. The liquid inlet 15 is a through hole for injecting electrolyte into the case 10 after the sealing plate 14 is assembled to the exterior body 12. The liquid inlet 15 is sealed by a sealing member 16 after the electrolyte is injected. The gas exhaust valve 17 is a thin-walled portion that is configured to break when the pressure inside the case 10 reaches or exceeds a predetermined value, thereby discharging gas inside the case 10 to the outside. The terminal outlet holes 18 and 19 are formed at both ends of the sealing plate 14 in the long side direction Y. The terminal outlet holes 18 and 19 are through holes that penetrate the sealing plate 14 in the vertical direction Z (thickness direction of the sealing plate 14).

As shown in FIG. 2, the outer surface 12a1 of the bottom wall 12a has a plurality of recesses 12d. The recesses 12d are recessed from the outer surface 12a1 of the bottom wall 12a toward the inner surface 12a2 of the bottom wall 12a. In this embodiment, the recesses 12d have a bottom surface 12e. This increases the surface area of the outer surface 12a1 of the bottom wall 12a, improving the heat exchange efficiency with the temperature adjustment unit 400. Therefore, the temperature of the power storage device 100 can be effectively adjusted (cooled or heated). Note that there may be only one recess 12d. The recess 12d is provided, for example, by press molding. Note that the recesses 12d in each figure are shown diagrammatically, and the shape, number, arrangement, etc. do not necessarily correspond between the figures.

The number of recesses 12d is preferably 1/cm2 or more with respect to a planar area including the opening area of recesses 12d on the outer side surface 12a1 of the bottom wall 12a on which recesses 12d are provided (i.e., the area when recesses 12d are not provided on the outer side surface 12a1 of the bottom wall ^12a ) and may be 1.5/ ^cm2 or more, or 2/ ^cm2 or more. This increases the surface area of the outer side surface 12a1 of the bottom wall 12a, and allows the electricity storage device 100 to be cooled or heated more effectively.

In this embodiment, the inner surface 12a2 of the bottom wall 12a is provided with a convex portion 12f corresponding to the concave portion 12d. The convex portion 12f protrudes from the inner surface 12a2 of the bottom wall 12a toward the electrode body 20. The convex portion 12f contacts the electrode body 20 via a resin sheet 29, which is an insulating member. The convex portion 12f may directly contact the electrode body 20. Here, the tip surface 12g of the convex portion 12f contacts the electrode body 20. The tip surface 12g of the convex portion 12f faces the bottom surface 12e of the concave portion 12d. The contact of the convex portion 12f with the electrode body 20 makes it easier for the cooling or heating by the temperature adjustment unit 400 to be transmitted to the electrode body 20. The convex portion 12f is not an essential component. Also, the convex portion 12f does not have to have the tip surface 12g.

Figure 6A is a plan view showing a schematic arrangement pattern of the recesses 12d in the bottom wall 12a, as viewed from the outer surface 12a1 side of the bottom wall 12a. Figure 6B is a plan view showing a schematic shape of the recesses 12d, as viewed from the outer surface 12a1 side of the bottom wall 12a. Figure 6C is a cross-sectional view showing a schematic shape of the recesses 12d. Figure 6D is a schematic diagram showing the arrangement of the bottom wall 12a and the temperature adjustment unit 400.

As shown in FIG. 6A, in this embodiment, the bottom wall 12a has a row A in which a plurality of recesses 12d are arranged in the long side direction Y of the bottom wall 12a. The number of recesses 12d arranged in one row is not particularly limited, and may be, for example, 2 to 50, and preferably 10 to 40. In row A, the plurality of recesses 12d are preferably arranged at a distance from each other. In addition, it is preferable that the interval between adjacent recesses 12d is uniform. As a result, the recesses 12d are uniformly arranged in row A, so that the temperature of the power storage device 100 can be regulated more uniformly. Note that, since unavoidable misalignment may occur when the recesses 12d are formed, the interval between adjacent recesses 12d does not have to be strictly uniform, and for example, a misalignment of up to 5% with respect to the average value of the interval between adjacent recesses 12d in row A may be tolerated.

As shown in FIG. 6A, the bottom wall 12a has multiple rows A in the short side direction X. Here, three rows A are formed, but the number is not particularly limited. For example, there may be one row A. There may be two or more rows (e.g., 2 to 10 rows), but it is preferable that there are multiple rows A. This provides many recesses 12d in the bottom wall 12a and increases the surface area of the outer side surface 12a1 of the bottom wall 12a, allowing the energy storage device 100 to be cooled or heated more effectively. The number of recesses 12d in each row may be different or the same.

It is preferable that the spacing between adjacent rows A is constant. This allows the recesses 12d to be more uniformly arranged in the short side direction X, so that the energy storage device 100 can be cooled or heated more uniformly. As described above, since unavoidable misalignment may occur when forming the recesses 12d, for example, a deviation of up to 5% in the spacing between rows A with respect to the average spacing between adjacent rows A may be tolerated.

The shape of the recess 12d is not particularly limited, but as shown in Figures 6A to 6D, in this embodiment, a truncated cone-shaped recess 12d is provided. The recess 12d gradually narrows from the outer surface 12a1 of the bottom wall 12a toward the bottom surface 12e of the recess 12d. The recess 12d has a side surface 12i between the outer surface 12a1 of the bottom wall 12a and the bottom surface 12e of the recess 12d.

As shown in Figures 6B and 6C, the opening of the recess 12d is circular in plan view with a radius R. The radius R is not particularly limited, but may be, for example, 1 mm or more, 1.5 mm or more, 2 mm or more, or 2.5 mm or more. The radius R may be, for example, 5 mm or less, 4.5 mm or less, 4 mm or less, or 3.5 mm or less.

6C, the height H (depth) of the recess 12d is not particularly limited, but may be, for example, 1 mm or more, 1.5 mm or more, or 2 mm or more. This increases the surface area of the outer surface 12a1 of the bottom wall 12a, and the power storage device 100 can be cooled or heated more effectively. The height H of the recess 12d may be, for example, 5 mm or less, 4 mm or less, or 3 mm or less. When the inner surface 12a2 of the bottom wall 12a of the power storage device 100 has a protrusion 12f corresponding to the recess 12d, if the height H of the recess 12d is too high, the storage space for the electrode body 20 inside the case 10 may be narrowed, and the energy density may be reduced. The height of the protrusion 12f is the same as the height H of the recess 12d.

The angle θ (see FIG. 6C) of the side surface 12i of the recess 12d when the opening of the recess 12d is used as a reference is not particularly limited, and may be, for example, 15° or more, 30° or more, or 45° or more. The angle θ may be, for example, 90° or less, 75° or less, or 60° or less. When the recess 12d is formed by press molding, it is preferable that the angle θ be 90° or less from the viewpoint of ease of molding.

In a plan view, when the plan area S including the opening area of the recess 12d on the outer side surface 12a1 of the bottom wall 12a (first wall) is taken as 100%, the total ratio of the opening area S1 of the recess 12d is, for example, 10% or more, preferably 20% or more, and more preferably 30% or more. This sufficiently increases the surface area of the outer side surface 12a1 of the bottom wall 12a, and the power storage device 100 can be cooled or heated more effectively. In addition, when the plan area S including the opening area of the recess 12d on the outer side surface 12a1 of the bottom wall 12a is taken as 100%, the total ratio of the opening area S1 of the recess 12d can be, for example, 60% or less, 50% or less, or 40% or less. If the ratio of the opening area of the recess 12d is too high, the strength of the bottom wall 12a of the case 10 may be impaired.
In this specification, the total area of bottom surface 12e and side surface 12i of recess 12d is referred to as the internal area of recess 12d, and the opening area of recess 12d is the area of the opening excluding the internal area (see FIG. 6C).

The total ratio of the internal area of the recesses 12d to the surface area of the outer side 12a1 of the bottom wall 12a (first wall) (including the internal area of the recesses 12d, but not including the opening area of the recesses 12d) is, for example, 20% or more, preferably 40% or more, more preferably 50% or more, and even more preferably 60% or more. This sufficiently increases the surface area of the outer side 12a1 of the bottom wall 12a, allowing the energy storage device 100 to be cooled or heated more effectively. In addition, the ratio of the internal area of the recesses 12d to the surface area of the outer side 12a1 of the bottom wall 12a (first wall) is, for example, 80% or less, and preferably 70% or less.

Efficiency in cooling or heating the power storage device 100 is particularly required when the power storage device 100 is large, and the present technology is highly effective in such cases. Therefore, the planar area S including the opening area of the recess 12d on the outer side surface 12a1 of the bottom wall 12a can be, for example, ⁵⁰ cm2 or more, ¹⁰⁰ cm2 or more, or ¹²⁰ cm2 or more.

2 to 4, in this embodiment, the outer surface of the case 10 is covered with an insulating sheet 96. The insulating sheet 96 ensures insulation of the case 10 in the event that the power storage module 500 is submerged in water. In this embodiment, the outer surface of the first side wall 12b and the outer surface of the second side wall 12c are covered with the insulating sheet 96. The insulating sheet 96 may also be arranged on the outer surface 12a1 of the bottom wall 12a. It is preferable that the insulating sheet 96 is not arranged in the recess 12d. By not arranging the insulating sheet 96 in the recess 12d, the power storage device 100 can be cooled or heated effectively. The insulating sheet 96 is made of resin, and may be made of, for example, polyolefin such as polyethylene (PE).

The positive electrode terminal 30 is attached to one end of the sealing plate 14 in the long side direction Y (the left end in FIG. 2). The negative electrode terminal 40 is attached to the other end of the sealing plate 14 in the long side direction Y (the right end in FIG. 2). The positive electrode terminal 30 and the negative electrode terminal 40 are preferably attached to the sealing plate 14. The positive electrode terminal 30 and the negative electrode terminal 40 are inserted into the terminal pull-out holes 18, 19, and are partially exposed on the surface of the sealing plate 14. The positive electrode terminal 30 and the negative electrode terminal 40 are electrically connected to other electricity storage devices and external equipment via external connection members such as bus bars.

As shown in FIG. 2, the positive electrode terminal 30 is electrically connected to the positive electrode 22 (see FIG. 5) of the electrode body 20 inside the case 10 through the positive electrode current collecting member 50 and a positive electrode tab group 22g (i.e., a plurality of stacked positive electrode tabs 22t) described later. The positive electrode terminal 30 is also electrically connected to the external positive electrode current collecting member 52 outside the case 10. The positive electrode terminal 30 is preferably made of metal, more preferably made of aluminum or an aluminum alloy, for example. The negative electrode terminal 40 is electrically connected to the negative electrode 24 (see FIG. 5) of the electrode body 20 inside the case 10 through the negative electrode current collecting member 60 and a negative electrode tab group 24g (i.e., a plurality of stacked negative electrode tabs 24t) described later. The negative electrode terminal 40 is also electrically connected to the external negative electrode current collecting member 62 outside the case 10. The negative electrode terminal 40 is preferably made of metal, more preferably made of copper or a copper alloy, for example. The positive electrode terminal 30 and the negative electrode terminal 40 are insulated from the sealing plate 14 by a gasket 92. The gasket 92 is preferably made of resin.

The positive electrode current collecting member 50 is a conductive member, and is attached to the sealing plate 14 here. As shown in FIG. 2, the positive electrode current collecting member 50 is insulated from the inner surface of the sealing plate 14 by an internal insulating member 94 made of resin. The positive electrode current collecting member 50 electrically connects the positive electrode tab group 22g of the electrode body 20 and the positive electrode terminal 30. The positive electrode current collecting member 50 has a plate-shaped first region extending in the long side direction Y along the inner surface of the sealing plate 14. One end (the right side in FIG. 2) of the positive electrode current collecting member 50 (specifically, the first region) in the long side direction Y is electrically connected to the positive electrode tab group 22g. The other end (the left side in FIG. 2) of the positive electrode current collecting member 50 (specifically, the first region) in the long side direction Y is electrically connected to the lower end 30c of the positive electrode terminal 30. The positive electrode current collecting member 50 is preferably made of a metal with excellent conductivity, for example, aluminum or an aluminum alloy. The positive electrode current collecting member 50 may be made of the same metal as the positive electrode tab 22t and/or the positive electrode terminal 30.

The external positive current collecting member 52 is a conductive member and is electrically connected to the positive terminal 30 outside the case 10. Here, the external positive current collecting member 52 is insulated from the outer surface of the sealing plate 14 by a gasket 92. The external positive current collecting member 52 has a plate-shaped portion extending in the direction Y along both sides of the outer surface of the sealing plate 14. A conductive member such as a bus bar can be connected to the plate-shaped portion. The external positive current collecting member 52 is preferably made of a metal with excellent conductivity, for example, aluminum or an aluminum alloy. The external positive current collecting member 52 can be made of the same type of metal as the positive terminal 30. The external positive current collecting member 52 is not a required component.

The negative electrode current collecting member 60 is a conductive member, and is attached to the sealing plate 14 here. The negative electrode current collecting member 60 is insulated from the inner surface of the sealing plate 14 by an internal insulating member 94 made of resin. The negative electrode current collecting member 60 electrically connects the negative electrode tab group 24g of the electrode body 20 and the negative electrode terminal 40. As shown in FIG. 2, the negative electrode current collecting member 60 has a plate-shaped first region extending in the long side direction Y along the inner surface of the sealing plate 14. One end (the left side in FIG. 2) of the negative electrode current collecting member 60 (specifically, the first region) in the long side direction Y is electrically connected to the negative electrode tab group 24g. The other end (the right side in FIG. 2) of the negative electrode current collecting member 60 (specifically, the first region) in the long side direction Y is electrically connected to the lower end 40c of the negative electrode terminal 40. The negative electrode current collecting member 60 is preferably made of a metal with excellent conductivity, for example, copper or a copper alloy. The negative electrode current collecting member 60 may be made of the same metal as the negative electrode tab 24t and/or the negative electrode terminal 40.

The external negative electrode current collecting member 62 is a conductive member and is electrically connected to the negative electrode terminal 40 outside the case 10. Here, the external negative electrode current collecting member 62 is insulated from the outer surface of the sealing plate 14 by a gasket 92. The external negative electrode current collecting member 62 has a plate-shaped portion extending in both side directions Y along the outer surface of the sealing plate 14. A conductive member such as a bus bar can be connected to the plate-shaped portion. The external negative electrode current collecting member 62 is preferably made of a metal with excellent conductivity, for example, copper or a copper alloy. The external negative electrode current collecting member 62 can be made of the same type of metal as the negative electrode terminal 40. Note that the external negative electrode current collecting member 62 is not a required component.

3 and 4, in the electricity storage device 100 of this embodiment, a plurality of electrode bodies 20 (specifically, two) are housed in the case 10. However, the number of electrode bodies 20 arranged in one case 10 is not particularly limited, and may be one or three or more. The electrode body 20 is arranged inside the case 10 while being covered with an insulating resin sheet 29 (insulating member). This prevents the electrode body 20 from coming into direct contact with the exterior body 12. The resin sheet 29 may be made of, for example, a polyolefin such as polyethylene (PE). The resin sheet 29 may also be configured to be bag-shaped or box-shaped.

As shown in Figures 2 and 5, the electrode body 20 has a first stacking end surface 20a. The stacking end surface is a surface on which the end of the positive electrode and the end of the negative electrode are arranged. It is preferable that the stacking end surface is not covered with a separator (i.e., the end of the positive electrode 22 and the end of the negative electrode 24 are exposed). In this embodiment, the electrode body 20 is a wound electrode body. In a wound electrode body, the stacking end surface is a surface perpendicular to the winding axis.

The symbol LD in FIG. 5 indicates the longitudinal direction of the electrode body 20, which is manufactured in a strip shape. In the longitudinal direction LD, the winding start side is indicated as S, and the winding end side is indicated as E. The symbol WD in FIG. 5 indicates the direction perpendicular to the longitudinal direction LD, and indicates the winding axis direction of the electrode body 20. Here, the winding axis direction WD is approximately parallel to the vertical direction Z of the electricity storage device 100.

As shown in Figures 2 and 3, the electrode body 20 has a flat outer shape. The flat electrode body 20 has a pair of curved portions 20r whose outer surfaces are curved, and a flat portion 20f whose outer surface is flat and connects the pair of curved portions 20r. As shown in Figure 5, the electrode body 20 has a first stacking end surface 20a and a second stacking end surface 20b perpendicular to the winding axis direction WD. The first stacking end surface 20a and the second stacking end surface 20b face each other. The first stacking end surface 20a is the stacking end surface on the side on which the positive electrode tab 22t and the negative electrode tab 24t are not formed. The second stacking end surface 20b is the stacking end surface on which the positive electrode tab 22t and the negative electrode tab 24t are formed. The first stacking end surface 20a of the electrode body 20 is arranged in a direction in which the first stacking end surface 20a faces the inner surface 12a2 of the bottom wall 12a. In other words, the electrode body 20 is housed inside the case 10 with the winding axis direction WD perpendicular to the sealing plate 14 and the bottom wall 12a. At this time, the second stacking end face 20b faces the sealing plate 14. As shown in FIG. 3, the pair of curved portions 20r faces the pair of second side walls 12c of the exterior body 12, and the flat portion 20f faces the first side wall 12b of the exterior body 12. By having the stacking end face (the first stacking end face 20a or the second stacking end face 20b, preferably the first stacking end face 20a) face the bottom wall 12a (first wall), the temperature of the electricity storage device 100 (particularly the temperature of the electrode body 20) can be effectively cooled or heated. This is because the stacking end face is the end of the positive electrode 22 or the end of the negative electrode 24, and the temperature is easily transmitted to the inside of the electrode body 20.

The electrode body 20 is not limited to a wound electrode body as long as it has a laminated end surface. In another embodiment, for example, the electrode body 20 may be a laminated electrode body in which multiple square-shaped (typically rectangular) positive electrodes and multiple square-shaped (typically rectangular) negative electrodes are stacked in an insulated state. The effect of the present technology is achieved by arranging the laminated end surface of the laminated electrode body so that it faces the inner surface of the first wall.

As shown in FIG. 5, the electrode body 20 is constructed by stacking a strip-shaped first separator 26, a strip-shaped negative electrode 24, a strip-shaped second separator 27, and a strip-shaped positive electrode 22, and winding them around a winding axis WL.

The positive electrode 22 may be the same as in the past, and is not particularly limited. As shown in FIG. 5, the positive electrode 22 has a positive electrode current collector foil 22c and a positive electrode active material layer 22a fixed to at least one surface of the positive electrode current collector foil 22c. The positive electrode current collector foil 22c is strip-shaped. The positive electrode current collector foil 22c is preferably made of metal, and more preferably made of metal foil. In this example, the positive electrode current collector foil 22c is aluminum foil.

At one end of the positive electrode current collector foil 22c in the winding axis direction WD (width direction perpendicular to the longitudinal direction LD), multiple positive electrode tabs 22t are provided. The multiple positive electrode tabs 22t protrude toward one side of the winding axis direction WD. The multiple positive electrode tabs 22t protrude in the winding axis direction WD beyond the first separator 26 and the second separator 27. The positive electrode tabs 22t are part of the positive electrode current collector foil 22c here, and are made of metal foil (aluminum foil). The multiple positive electrode tabs 22t are stacked at one end of the winding axis direction WD to form a positive electrode tab group 22g. The positive electrode tab group 22g is provided on the second stack end surface 20b. The positive electrode tab group 22g is electrically connected to the positive electrode terminal 30 via the positive electrode current collector member 50.

As shown in FIG. 5, the positive electrode active material layer 22a is provided in a strip shape along the longitudinal direction LD of the positive electrode current collector foil 22c. The positive electrode active material layer 22a contains a positive electrode active material that can reversibly store and release charge carriers. An example of the positive electrode active material is a lithium transition metal composite oxide. The positive electrode active material layer 22a may contain any component other than the positive electrode active material, such as various additive components such as a binder or a conductive material.

The negative electrode 24 may be the same as in the past, and is not particularly limited. As shown in FIG. 5, the negative electrode 24 has a negative electrode current collector foil 24c and a negative electrode active material layer 24a fixed to at least one surface of the negative electrode current collector foil 24c. The negative electrode current collector foil 24c is strip-shaped. The negative electrode current collector foil 24c is preferably made of metal, and more preferably made of metal foil. In this example, the negative electrode current collector foil 24c is copper foil.

A plurality of negative electrode tabs 24t are provided in the winding axis direction WD (width direction perpendicular to the longitudinal direction LD) of the negative electrode current collector foil 24c. The plurality of negative electrode tabs 24t protrude toward one side of the winding axis direction WD. The plurality of negative electrode tabs 24t protrude in the winding axis direction WD beyond the first separator 26 and the second separator 27. The negative electrode tab 24t is a part of the negative electrode current collector foil 24c here, and is made of metal foil (copper foil). The plurality of negative electrode tabs 24t are stacked at one end of the winding axis direction WD to form a negative electrode tab group 24g. The negative electrode tab group 24g is provided at the end on the same side as the end where the positive electrode tab group 22g is provided in the winding axis direction WD. The negative electrode tab group 24g is provided on the second stacking end surface 20b. The negative electrode tab group 24g is electrically connected to the negative electrode terminal 40 via the negative electrode current collecting member 60.

As shown in FIG. 5, the negative electrode active material layer 24a is provided in a band shape along the longitudinal direction LD of the negative electrode current collector foil 24c. The negative electrode active material layer 24a contains a negative electrode active material that can reversibly store and release charge carriers. Examples of the negative electrode active material include carbon materials such as graphite. The negative electrode active material layer 24a may contain optional components other than the negative electrode active material, such as various additive components such as binders, thickeners, and dispersants.

The first separator 26 is disposed between the positive electrode 22 and the negative electrode 24. The first separator 26 is a member that insulates the positive electrode 22 and the negative electrode 24. The second separator 27 is disposed in the outermost layer of the electrode body 20. Inside the wound electrode body 20, the second separator 27 is disposed between the positive electrode 22 and the negative electrode 24. The second separator 27 is a member that insulates the positive electrode 22 and the negative electrode 24 inside the electrode body 20. As the first separator 26 and the second separator 27, for example, a resin porous sheet made of a polyolefin resin such as polyethylene (PE) or polypropylene (PP) is suitable.

The electrolyte can be any electrolyte used in a general power storage device without any particular limitations. An example of the electrolyte is a non-aqueous electrolyte in which a supporting salt is dissolved in a non-aqueous solvent. In the non-aqueous electrolyte used in a lithium ion secondary battery, a carbonate-based solvent such as ethylene carbonate, dimethyl carbonate, or ethyl methyl carbonate can be used as the non-aqueous solvent. In addition, a fluorine-containing lithium salt such as _LiPF6 can be used as the supporting salt. The electrolyte may contain an additive as necessary.

The amount of electrolyte is not particularly limited, but when the power storage device 100 is fully charged (i.e., the state of charge (SOC) is 100%), the height of the electrolyte level between the case 10 and the electrode body 20 is preferably 1/5 or more, more preferably 2/5 or more, of the height of the case 10. The height of the electrolyte level refers to the height of the liquid level when the first wall (here, the bottom wall 12a) of the case 10 is placed vertically (in the direction of gravity). The height of the case 10 refers to the height in the vertical direction Z from the inner surface of the first wall of the case 10 (here, the inner surface 12a2 of the bottom wall 12a). By having a large amount of electrolyte between the case 10 and the electrode body 20, the power storage device 100 can be cooled or heated more effectively.

The temperature adjustment unit 400 is arranged to face the outer surface of the first wall of the power storage device 100. Preferably, the temperature adjustment unit 400 is in contact with the outer surface of the power storage device 100. As shown in FIG. 6D, in this embodiment, the temperature adjustment unit 400 is arranged to face the outer surface 12a1 of the bottom wall 12a of the multiple power storage devices 100. The temperature adjustment unit 400 may be capable of cooling and/or heating the multiple power storage devices 100. In this embodiment, as shown in FIG. 1, the temperature adjustment unit 400 includes a thin portion 410, a thick portion 420, a convex portion 432, and a convex portion group 430 in which multiple convex portions 432 are gathered. As shown in FIG. 6D, in this embodiment, a hollow portion 422 is provided inside the thick portion 420. The hollow portion 422 is filled with a temperature adjustment medium, such as a cooling medium or a heating medium. The thin portion 410 and the thick portion 420 are preferably made of a thermally conductive material, for example, aluminum.

As shown in FIG. 1, the thin-walled portion 410 includes an intake port 412 and an exhaust port 414. The intake port 412 is a portion that supplies the temperature control medium to the inside of the temperature control portion 400. The supplied temperature control medium is supplied to the hollow portion 422 of the thick-walled portion 420. The exhaust port 414 is a portion that discharges the temperature control medium in the hollow portion 422 from the temperature control portion 400. The temperature control medium discharged from the exhaust port 414 may be introduced again into the intake port 412 to circulate the temperature control medium. In this case, it is preferable to cool or heat the temperature control medium before the temperature control medium discharged from the exhaust port 414 is introduced into the intake port 412.

The temperature control medium may be a liquid or a gas. Examples of liquids used as temperature control mediums include water and coolants. Examples of gases used as temperature control mediums include air.

The temperature control unit 400 is not limited to using a temperature control medium as described above. For example, the temperature control unit 400 may include a heating wire.

It is preferable that a part of the temperature adjustment unit 400 is disposed inside the recess 12d of the outer surface 12a1 of the bottom wall 12a (first wall) of the power storage device 100. This allows the power storage device 100 to be cooled or heated more effectively. In this embodiment, as shown in FIG. 1 and FIG. 6D, a plurality of protrusions 432 are provided on the surface of the thick portion 420 facing the first wall of the power storage device 100. As shown in FIG. 6D, the protrusions 432 protrude from the surface of the thick portion 420 toward the outer surface 12a1 of the bottom wall 12a of the power storage device 100. At least a part of the protrusions 432 of the temperature adjustment unit 400 is disposed inside the recess 12d of the bottom wall 12a. The protrusions 432 of the temperature adjustment unit 400 are provided to correspond to the shape of the recess 12d.

As shown in FIG. 1, the temperature adjustment unit 400 has a plurality of convex groups 430 each consisting of a plurality of convex portions 432. In each of the plurality of convex groups 430, the convex portions 432 are arranged so as to correspond to the positions of the concave portions 12d in the bottom wall 12a of the opposing power storage device 100. The number of convex groups 430 may be the same as the number of power storage devices 100 included in the power storage module 500. However, the convex groups 430 do not necessarily need to face the bottom wall 12a of the power storage device 100, and the number of convex groups 430 may be fewer than the number of power storage devices 100 included in the power storage module 500.

It is preferable that the hollow portion 422 is also provided inside the protruding portion 432 of the temperature adjustment portion 400. This allows the temperature adjustment medium to be supplied also inside the protruding portion 432, making it possible to more effectively cool or heat the electricity storage device 100.

The temperature adjustment unit 400 may be provided with a heat conductive member on a surface that comes into contact with at least one first wall of the power storage device 100. The heat conductive member may be a known material, and may be made of, for example, silicone rubber. The shape of the heat conductive member is not particularly limited, and may be, for example, sheet-like. By providing the temperature adjustment unit 400 with a heat conductive member, any gap that may occur between the temperature adjustment unit 400 and the outer surface of the first wall of the power storage device 100 can be filled, and therefore the power storage device 100 can be cooled or heated more effectively.

The power storage module 500 can be used for various purposes, but can be suitably used, for example, as a power source (driving power source) for a motor mounted on a vehicle such as a passenger car or truck. The type of vehicle is not particularly limited, but examples include a plug-in hybrid electric vehicle (PHEV), a hybrid electric vehicle (HEV), and a battery electric vehicle (BEV).

Although the preferred embodiment of the present technology has been described above, the above embodiment is merely an example. The present technology can be implemented in various other forms. The technology described in the claims includes various modifications and variations of the above-exemplified embodiment. For example, it is possible to replace part of the above-described embodiment with other modifications, and it is also possible to add other modifications to the above-described embodiment. Furthermore, if a technical feature is not described as essential, it can also be deleted as appropriate.

For example, in the above embodiment, the shape of the recess 12d provided on the outer side surface 12a1 of the bottom wall 12a of the case 10 was a truncated cone. However, the shape of the recess 12d is not limited to this. FIG. 7A is a plan view that shows a typical arrangement pattern of the recesses on the bottom wall of the case of the power storage device in the first modification. FIG. 7B is a plan view that shows a typical shape of the recesses on the bottom wall of the case of the power storage device in the first modification. FIG. 7C is a cross-sectional view that shows a typical shape of the recesses on the bottom wall of the case of the power storage device in the first modification. As shown in FIGS. 7A to 7C, in the first modification, a truncated pyramid recess 12d1 is provided on the outer side surface 12a1 of the bottom wall 12a of the case. The recess 12d1 is gradually narrowed toward the bottom surface 12e1. The recess 12d1 has a side surface 12i1 between the outer side surface 12a1 of the bottom wall 12a and the bottom surface 12e1 of the recess 12d1.

As shown in Figures 7B and 7C, the opening of the recess 12d1 is a square with a side of length x. The length x is not particularly limited, but may be, for example, 2 mm or more, 3 mm or more, 4 mm or more, or 5 mm or more. The length x may be, for example, 8 mm or less, 7 mm or less, or 6 mm or less.

The height H1 (depth) of the recess 12d1 may be the same as the height H of the protrusion 12f in the above-described embodiment. The angle θ1 of the side surface 12i1 of the recess 12d1 when the opening of the recess 12d1 is used as a reference may be the same as the angle θ of the protrusion 12f in the above-described embodiment.

Figure 8A is a plan view showing a typical arrangement pattern of recesses in the bottom wall of the case of the power storage device in the modified example 2. Figure 8B is a plan view showing a typical shape of the recesses in the bottom wall of the case of the power storage device in the modified example 2. Figure 8C is a cross-sectional view showing a typical shape of the recesses in the bottom wall of the case of the power storage device in the modified example 2. As shown in Figures 8A to 8C, in the modified example 2, an arc-shaped recess 12d2 is provided on the outer side surface 12a1 of the bottom wall 12a of the case. The recess 12d2 has a curved bottom surface 12e2. The opening of the recess 12d2 is a circle having a radius R2 in a plan view. The radius R2 may be the same as the radius R of the opening of the recess 12d in the above-mentioned embodiment. The height H2 (depth) of the recess 12d2 may be the same as the height H of the recess 12d in the above-mentioned embodiment.

As described above, specific aspects of the technology disclosed herein include those described in the following sections.
Item 1: An energy storage module comprising a plurality of energy storage devices and a temperature adjustment unit, wherein the energy storage devices include an electrode body including a positive electrode and a negative electrode, an electrolyte, and a case for accommodating the electrode body and the electrolyte, the case including a first wall having an outer surface with a recess, the temperature adjustment unit being disposed so as to face the outer surface of the first wall, and a stacking end face of the electrode body being disposed in a direction facing the inner surface of the first wall.
Item 2: The energy storage module according to item 1, wherein a portion of the temperature adjustment section is disposed within the recess.
Item 3: The energy storage module according to item 1 or ² , wherein the number of the recesses relative to a planar area including an opening area of the recesses on the outer surface of the first wall is 1/cm2 or more.
Item 4: The storage module according to any one of items 1 to 3, wherein the first wall is a bottom wall of the case, and when the storage device is fully charged, the height of a liquid surface of the electrolyte located between the case and the electrode body is 1/5 or more of the height of the case.
Item 5: The energy storage module according to any one of items 1 to 4, wherein an outer surface of the case is covered with an insulating sheet, and the insulating sheet is not disposed in the recess.
Item 6: The energy storage module according to any one of items 1 to 5, wherein the first wall is a rectangular bottom wall of the case, the bottom wall has a row in which the recesses are aligned in a long side direction of the bottom wall, a plurality of the rows are provided in a short side direction of the bottom wall, and the recesses are arranged at a distance from each other.
Item 7: The storage module according to any one of items 1 to 6, wherein a convex portion corresponding to the concave portion is provided on an inner surface of the first wall, and the convex portion is in contact with the electrode body directly or via an insulating member.
Item 8: An electricity storage device comprising an electrode body including a positive electrode and a negative electrode, an electrolyte, and a case for accommodating the electrode body and the electrolyte, wherein the case comprises a first wall having an outer surface with a recess, and a stacking end face of the electrode body is arranged in a direction facing the inner surface of the first wall.
Item 9: The electricity storage device according to item 8, wherein the number of the recesses relative to a planar area including an opening area of the recesses on the outer surface of the first wall is 1/cm ² or more.
Item 10: The electricity storage device according to item 8 or 9, wherein the first wall is a bottom wall of the case, and when the electricity storage device is fully charged, the height of a liquid surface of the electrolyte located between the case and the electrode body is ⅕ or more of the height of the case.
Item 11: The energy storage device according to any one of items 8 to 10, wherein the first wall is a rectangular bottom wall of the case, the bottom wall has a row in which the recesses are aligned in a long side direction of the bottom wall, a plurality of the rows are provided in a short side direction of the bottom wall, and the recesses are arranged at a distance from each other.
Item 12: The electric storage device according to any one of items 8 to 11, wherein a convex portion corresponding to the concave portion is provided on the inner surface of the first wall, and the convex portion is in contact with the electrode body directly or via an insulating member.

REFERENCE SIGNS LIST 10 Case 12 Exterior body 12a Bottom wall 12d Recess 20 Electrode body 30 Positive electrode terminal 40 Negative electrode terminal 100 Electricity storage device 200 Spacer 300 Restraint mechanism 400 Temperature adjustment section 430 Group of protrusions 432 Protrusion 500 Electricity storage module

Claims (12)

A plurality of power storage devices;
A power storage module including a temperature control unit,
The power storage device is
An electrode assembly including a positive electrode and a negative electrode;
An electrolyte;
a case that accommodates the electrode assembly and the electrolyte;
the case includes a first wall having an outer surface with a recess;
the temperature adjustment unit is disposed so as to face the outer surface of the first wall,
The stacked end surface of the electrode body is disposed in a direction facing the inner surface of the first wall.
Energy storage module. The energy storage module according to claim 1, wherein a portion of the temperature control unit is disposed within the recess. The energy storage module according to claim 1 , wherein the number of the recesses relative to a planar area including an opening area of the recesses on the outer surface of the first wall is 1/cm ² or more. the first wall is a bottom wall of the case,
When the power storage device is fully charged, the height of the liquid surface of the electrolyte located between the case and the electrode body is ⅕ or more of the height of the case.
The energy storage module according to claim 1 or 2. The outer surface of the case is covered with an insulating sheet,
The insulating sheet is not disposed in the recess.
The energy storage module according to claim 1 or 2. the first wall is a rectangular bottom wall of the case,
The bottom wall has a row in which the recesses are aligned in a long side direction of the bottom wall,
A plurality of the rows are provided in the short side direction of the bottom wall,
The recesses are spaced apart from one another.
The energy storage module according to claim 1 or 2. A convex portion corresponding to the concave portion is provided on an inner surface of the first wall,
The protrusion is in contact with the electrode body directly or via an insulating member.
The energy storage module according to claim 1 or 2. An electrode assembly including a positive electrode and a negative electrode;
An electrolyte;
An electricity storage device comprising the electrode body and a case that accommodates the electrolyte,
the case includes a first wall having an outer surface with a recess;
The stacked end surface of the electrode body is disposed in a direction facing the inner surface of the first wall.
Energy storage device. The power storage device according to claim 8 , wherein the number of the recesses relative to a planar area including an opening area of the recesses on the outer surface of the first wall is 1/cm ² or more. the first wall is a bottom wall of the case,
10. The power storage device according to claim 8, wherein when the power storage device is fully charged, the height of a liquid surface of the electrolyte located between the case and the electrode body is equal to or greater than ⅕ of the height of the case. the first wall is a rectangular bottom wall of the case,
The bottom wall has a row in which the recesses are aligned in a long side direction of the bottom wall,
A plurality of the rows are provided in the short side direction of the bottom wall,
The recesses are spaced apart from one another.
The electricity storage device according to claim 8 or 9. A convex portion corresponding to the concave portion is provided on an inner surface of the first wall,
The protrusion is in contact with the electrode body directly or via an insulating member.
The electricity storage device according to claim 8 or 9.

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