JP2021128820A - Power storage device - Google Patents

Abstract

To provide a power storage device in which retention of battery cells by a cell holder is improved, so that a performance of the power storage device can be improved.SOLUTION: A power storage device 1 includes a power storage part 80 and a holding part 82 which is arranged on one end of the power storage part 80 and holds the power storage part 80, the holding part 82 being formed so as to surround, in a circumferential direction, a side end crossing the one end of the power storage part 80. In the holding part 82, a portion of the holding part 82 facing a corner part 803 formed between one end 801 and a side end 802 of the power storage part 80 has at least one of a projecting portion 824 projected on the corner part 803 side in the portion surrounding in the circumferential direction and a recessed portion 825 recessed from the corner part 803 side in the portion surrounding in the circumferential direction.SELECTED DRAWING: Figure 5

Description

The present invention relates to a power storage device.

Conventionally, as a battery pack as a power storage device that is detachably mounted on an electric vehicle or the like, a battery pack having a plurality of battery cells held in a cell holder and a case for accommodating the battery core pack have been known. (See, for example, Patent Document 1).

International Publication No. 2019/064467

In the power storage device described in the above publication, the end portion of the cylindrical battery cell is inserted into a holding hole formed in the cell holder and held in the cell holder. However, it is desired to further improve the holding of the battery cell by the cell holder as compared with the power storage device described in the above publication.

An object of the present invention is to provide a power storage device in which the holding of a battery cell by a cell holder is improved, which can improve the performance of the power storage device.

In order to achieve the above object, the present invention has a power storage unit (for example, a battery cell 80 described later) and a holding unit (for example, a holding unit (for example, a holding unit 801 described later) arranged at one end of the power storage unit (for example, an end face 801 described later) to hold the power storage unit. A cell holder 82) described later is provided, and the holding portion is formed so as to surround a side end (for example, a side surface 802 described later) intersecting with the one end of the power storage unit in the circumferential direction. The portion of the holding portion facing the corner portion (for example, the corner portion 803 described later) formed between the one end and the side end of the portion is projected toward the corner portion in the portion surrounded in the circumferential direction. A power storage device having at least one of a convex portion (for example, a convex portion 824 described later) or a concave portion (for example, a concave portion 825 described later) recessed from the corner side in a portion surrounding the circumferential direction. (For example, the battery pack 1 described later) is provided.

As a result, the position where the corner portion of the power storage unit abuts on the convex portion can be appropriately changed according to the dimensions of the power storage unit. Therefore, regardless of whether the power storage unit is large or small, the end portion of the power storage unit can be reliably sandwiched between the convex portion and the concave portion and held, and the power storage unit is reliably held by the holding unit. It becomes possible to do. That is, the holding unit can absorb manufacturing variations in the external dimensions of the power storage unit. As a result, it is possible to ensure that the power storage unit is in contact with the holding unit, and it is possible to obtain a power storage device in which the holding of the power storage unit by the holding unit is improved. As a result, it is possible to improve the performance of the power storage device as a whole.

In this case, it is preferable that the convex portion is provided at a position lower than the lower end in the vertical direction of the power storage unit, or the concave portion is provided at a position higher than the upper end in the vertical direction of the power storage unit. This makes it possible to increase the gap between the lower surface of the power storage unit and the holding portion and reduce the gap between the upper surface of the power storage unit and the holding portion. As a result, it is possible to suppress heat transfer from the lower side of the power storage unit and promote heat transfer from the upper side of the power storage unit.

In this case, it is preferable that the convex portion has a curved surface (for example, a curved surface 8241 described later) recessed from the corner portion side at a position facing the corner portion. As a result, the position where the corner portion of the power storage unit abuts on the curved surface of the convex portion can be appropriately changed according to the dimensions of the power storage unit.

In this case, it is preferable that the concave portion has a similar portion having a similar shape to the corner portion (for example, a similar portion 8251 described later) at a position facing the corner portion. As a result, the corner portion of the power storage unit can be engaged with the similar portion. Therefore, even if the position where a part of the corner portion of the power storage unit abuts on the curved surface of the convex portion is changed when the power storage unit having slightly different external dimensions of the power storage unit is held by the holding unit. The corner portion of the power storage unit can be engaged with the similar portion through a slight gap.

In this case, in the portion surrounding the side end of the holding portion, it is preferable that the heat conduction to the one end side is larger than the heat conduction in the direction orthogonal to the direction to the one end.

As a result, in the holding portion surrounding the one end portion and the other end portion of the power storage unit, heat can be transferred toward the axial end portion of the power storage unit. This makes it possible to effectively dissipate heat from the power storage unit. As a result, the performance of the battery pack can be improved.

In this case, the portion surrounding the side end of the holding portion is preferably composed of a particle-oriented material (for example, filler 8221 described later). More specifically, the portion surrounding the side end of the holding portion is preferably composed of a material oriented with a heat transfer filler (for example, filler 8221 described later).

As a result, in the holding portion surrounding the one end portion and the other end portion of the power storage unit, it is possible to more effectively transfer heat toward the axial end portion of the power storage unit. This makes it possible to effectively dissipate heat from the power storage unit.

In this case, it is preferable that the holding portions have a pair of holding portions that are arranged apart from each other and hold the one end and the other end of the power storage portion, respectively. As a result, in the pair of holding portions that hold one end and the other end of the power storage unit, the storage unit can be reliably held by the holding unit.

In this case, it is preferable that the holding unit and the power storage unit are housed in a housing (for example, a storage battery case 10 described later). As a result, the housing can protect the power storage unit that is securely held by the holding unit.

In this case, it is preferable that the power storage unit has a cylindrical cell (for example, a battery cell 80 described later). As a result, cylindrical cells having different diameters can be reliably held by the holding portion.

According to the present invention, it is possible to provide a power storage device in which the performance of the power storage device can be improved and the holding of the battery cell by the cell holder is improved.

It is a perspective view which shows the battery pack which is the power storage device as one Embodiment of this invention. It is an exploded perspective view which shows the battery pack which is the power storage device as one Embodiment of this invention. It is an enlarged sectional view which shows the cell holder of the battery pack which is the power storage device as one Embodiment of this invention. It is an enlarged cross-sectional perspective view which shows the cell holder of the battery pack which is the power storage device as one Embodiment of this invention. FIG. 5 is an enlarged cross-sectional view showing a state in which a battery cell having a small diameter is held in a holding hole of a cell holder of a battery pack which is a power storage device according to an embodiment of the present invention. FIG. 5 is an enlarged cross-sectional view showing a state in which a large-diameter battery cell is held in a holding hole of a cell holder of a battery pack which is a power storage device according to an embodiment of the present invention. It is a figure which shows the transfer of the heat generated in the battery cell in the cell holder of the battery pack which is the power storage device as one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a perspective view showing the battery pack 1. FIG. 2 is an exploded perspective view showing the battery pack 1. FIG. 3 is an enlarged cross-sectional view showing a cell holder 82 of the battery pack 1 which is a power storage device. FIG. 4 is an enlarged cross-sectional perspective view showing the cell holder 82 of the battery pack 1 which is a power storage device. FIG. 5 is an enlarged cross-sectional view showing a state in which a battery cell having a small diameter is held in a holding hole of a cell holder 82 of a battery pack 1 which is a power storage device. FIG. 6 is an enlarged cross-sectional view showing a state in which a large-diameter battery cell 80 is held in a holding hole 821 of a cell holder 82 of a battery pack 1 which is a power storage device. FIG. 7 is a diagram showing the transfer of heat generated in the battery cell 80 in the cell holder 82 of the battery pack 1 which is a power storage device.
Hereinafter, the upper side (the side on which the handle 42 is provided) shown in FIG. 1 is defined as the upper side, and the opposite side (the lower side shown in FIG. 1) is defined as the lower side.

The portable battery pack 1 as a power storage device is suitably applied to, for example, a portable drive power source that is detachably mounted on an electrically assisted bicycle, an electric motorcycle, or the like. The battery pack 1 as a power storage device includes a storage battery case 10 which forms an outer body of a substantially rectangular parallelepiped, and a battery group 16 housed inside the storage battery case 10.

The storage battery case 10 houses the battery core packs 14a and 14b. The storage battery case 10 can be formed of, for example, a metal such as aluminum, a resin (including a fiber reinforced resin), or the like. The storage battery case 10 has a bottom case 24, an outer shell case 26, and a top case 28.

The bottom case 24 is a housing that is formed separately from the battery group 16, is located outside the battery group 16 and is arranged below the battery group 16 and has an upper end that opens, and has a rectangular shape in a plan view. Have. A connector portion 33 and the like are housed inside the bottom case 24.

The connector portion 33 is exposed to the outside of the case 12 through, for example, a through hole (not shown) formed in the bottom wall of the bottom case 24, and is charged to charge the power supply port of the electric vehicle or the battery group 16. It can be electrically connected to the device. By connecting the connector unit 33 to the power supply port or the charging device, the power supply port or the charging device and the battery group 16 are electrically connected via the BMU 22.

The outer shell case 26 (see FIG. 1) has a square tubular shape and covers the side surface of the battery group 16. The upper end of the outer shell case 26 opens upward at the upper opening 26a, and the lower end of the outer shell case 26 opens downward at the lower opening 26b. The battery group 16, BMU22, and the like are housed in the internal space of the outer shell case 26 in a state where the lower opening 26b is covered by the bottom case 24 and the upper opening 26a is covered by the top case 28.

The top case 28 is formed separately from the battery group 16, is a housing that is located outside the battery group 16 and is arranged above the battery group 16 and has an open lower end, and has a rectangular shape in a plan view. doing.

Further, as shown in FIG. 1, a handle 42 is connected to the upper surface 28a of the top case 28. The handle 42 is gripped by the user, for example, when carrying the battery pack 1.

The two battery core packs 14a and 14b constituting the battery group 16 are mirror-symmetrical to each other. Therefore, in the following description, only one battery core pack 14a will be mainly described, and the description of the other battery core pack 14b will be omitted. When the battery core packs 14a and 14b are not individually distinguished, the two battery core packs 14a and 14b are collectively referred to as the battery core pack 14.

As shown in FIG. 2, the battery core pack 14a includes a plurality of battery cells 80 and two cell holders 82 (positive electrode side holders 82a) arranged at one end and the other end of the battery cells 80 as holding portions for holding the battery cells 80. , Negative electrode side holder 82b). The outer shape of the cell holder 82 has a rectangular parallelepiped shape. The battery cell 80 is, for example, a so-called cylindrical cell having a columnar outer shape, and positive electrode terminals 86 and negative electrode terminals 88 are provided at both ends in the axial direction, respectively. The battery cell 80 is preferably a lithium ion secondary battery, but is not particularly limited thereto, and for example, an all-solid-state battery or a secondary battery such as a nickel hydrogen battery or a nickel cadmium battery may be used. Further, the battery cell may be a square cell instead of a cylindrical cell, and the cell holder may be formed in a shape capable of holding such a square cell.

In the plurality of battery cells 80, the positive electrode terminals 86 are arranged flush with each other, and the negative electrode terminals 88 are arranged flush with each other. A potting material (not shown) made of an insulating resin or the like may be filled between the peripheral surfaces of the plurality of battery cells 80.

Further, a plurality of bus bar plates 100 (see FIG. 2) are provided so as to cover each of the positive electrode terminal 86 and the negative electrode terminal 88. The negative electrode terminal 88 side of one battery core pack 14a and the positive electrode terminal 86 side of the other battery core pack 14b face each other, and the two battery core packs 14a and 14b are connected to form the battery group 16. There is.

A bus bar plate 100 faces each of the positive electrode terminals 86 of one battery core pack 14a and each negative electrode terminal of the other battery core pack 14b. The bus bar plate 100 connects the positive electrode terminals 86 to each other or the negative electrode terminals 88 to each other in a predetermined number in parallel. The plurality of bus bar plates 100 are connected to the connector portion 33 via the BMU 22 in a state of being connected in series with each other.

A heat transfer sheet 84 made of a high thermal conductive material is provided on the outer side of the plurality of bus bar plates 100 located closer to the outer side of the battery group 16. The surface of the heat transfer sheet 84 facing the bus bar plate 100 comes into surface contact. As a result, the thermal connection between the bus bar plate 100 and the outer shell case 26 is established, and effective heat dissipation is performed.

As shown in FIG. 2, the BMU 22 is arranged below the battery core packs 14a and 14b. The BMU 22 is, for example, a state of the battery core pack 14 detected from the temperature, voltage, etc. of the battery cell 80, the control unit that controls the charging / discharging of the battery core pack 14, the communication unit that communicates with the electric vehicle and the charging device, and the like. It has a storage unit for storing.

Next, the cell holder 82 constituting the battery core pack 14 will be described. Since the cell holder 82a and the cell holder 82b are arranged apart from each other and have a mirror-symmetrical structure, only the cell holder 82a will be described.

As shown in FIGS. 3 and 4, a plurality of cylindrical holding holes 821 are formed in the cell holder 82a so as to be separated by a wall portion 822. As shown in FIG. 5 and the like, one end and one other end of the battery cell 80 are inserted into the holding hole 821. Therefore, the portion of the cell holder 82a in which the holding hole 821 is formed is orthogonal to the end surface 801 of the cylindrical battery cell 80 in the longitudinal direction at the side end intersecting with one end of the battery cell 80, that is, at one end of the battery cell 80. The side surface (peripheral surface) 802 is surrounded in the circumferential direction of the battery cell 80.

At one end of the battery cell 80, as shown in FIG. 5, a corner portion 803 is formed by an end surface 801 and a side surface (peripheral surface) 802 of the cylindrical battery cell 80 in the longitudinal direction. The lower portion of the portion of 82a forming the portion of the holding hole 821 facing the corner portion 803 has a convex portion 824, and the upper portion has a concave portion 825. doing. That is, as shown in FIG. 4 and the like, the portion of the cell holder 82a forming the lower side of the one end portion of the holding hole 821 has the convex portion 824, and forms the upper side of the one end portion of the holding hole 821. The portion of the cell holder 82a is provided with a recess 825.

More specifically, as shown in FIG. 3 and the like, the convex portion 824 has a shape protruding from the right-angled corner portion so as to fill the lower right-angled corner portion of the end portion of the holding hole 821 in a cross-sectional view. It has an R-shaped curved surface 8241 that is recessed in a direction away from the corner portion 803 side at a position facing the corner portion 803 of the lower half of the battery cell 80.

More specifically, as shown in FIG. 3, the recess 825 is a right-angled corner portion on the upper side of the end portion of the holding hole 821 in a cross-sectional view, and faces the corner portion 803 of the upper half of the battery cell 80. At the position, it has a right-angled similar portion 8251 having a similar shape to the corner portion 803. That is, as shown in FIG. 4 and the like, in the portion of the wall portion 822 forming the lower half of the end portion of the holding hole 821 facing the corner portion 803 of the end portion of the battery cell 80 inserted into the holding hole 821. Is a portion of the wall portion 822 which is provided with a convex portion 824 and forms the upper half of the end portion of the holding hole 821 facing the corner portion 803 of the end portion of the battery cell 80 inserted into the holding hole 821. Is provided with a recess 825.

Since the convex portion 824 is configured as described above, as shown in FIG. 5 and the like, the convex portion 824 is provided at a position lower than the lower surface 8022 forming the lower end in the vertical direction of the battery cell 80. Further, as shown in FIG. 5 and the like, the recess 825 is provided at a position higher than the upper surface 8021 constituting the upper end of the battery cell 80 in the vertical direction. The corner portion 803 of the battery cell 80 is in contact with the upper end portion of the R-shaped curved surface 8241 of the convex portion 824, and in this state, the upper surface 8021 of the battery cell 80 forms the holding hole 821. It is in contact with the upper part of the peripheral surface 828. Therefore, the upper corner portion 803 of the battery cell 80 is engaged with the similar portion 8251 with a slight gap formed between the upper corner portion 803 and the wall portion 822 in the axial direction of the battery cell 80. Further, as shown in FIG. 5, a gap 826 is formed between the lower surface 8022 of the side surface 802 of the battery cell 80 and the lower portion 827 of the inner peripheral surface forming the holding hole 821.

Further, when the battery cell 80 having a diameter slightly larger than that of the battery cell 80 shown in FIG. 5 is inserted into the holding hole 821, the corner portion 803 of the battery cell 80 is formed by the R-shaped curved surface 8241 of the convex portion 824. It is in a state of being in contact with a portion slightly lower than the upper end portion, and in this state, the upper surface 8021 of the battery cell 80 is in contact with the upper inner peripheral surface 828 forming the holding hole 821. Therefore, the upper corner portion 803 of the battery cell 80 is located between the upper corner portion 803 and the wall portion 822 in the axial direction of the battery cell 80, as compared with the case where the battery cell 80 having a small diameter is inserted into the holding hole 821. A wider gap is formed to engage the similarity portion 8251. Further, as shown in FIG. 5, between the lower surface 8022 of the side surface 802 of the battery cell 80 and the lower portion 827 of the inner peripheral surface forming the holding hole 821, the battery cell 80 having the small diameter mentioned above has the holding hole 821. A narrower gap 826 is formed as compared to when inserted into. In FIGS. 5 and 6, the gap between the axial wall portion 822 and the corner portion 803 of the battery cell 80 in the portion where the upper corner portion 803 of the battery cell 80 is engaged with the similar portion 8251. Is not shown in the figure because it is a slight gap.

The portion of the wall portion 822 surrounding the side surface 802 of the battery cell 80 is made of a particle-oriented material. More specifically, as shown by an arrow in FIG. 7, the end side of the battery cell 80 held in the holding hole 821 (the direction along the axis of the battery cell 80 and the end face 801 of the battery cell 80). The filler 8221 is composed of a material oriented (heat transfer filler oriented) so as to transfer heat in the direction (direction toward).

Therefore, as shown by an arrow in FIG. 7, in the portion of the wall portion 822 surrounding the side surface 802 of the battery cell 80, the end side of the battery cell 80 held in the holding hole 821 (of the battery cell 80). The heat conduction in the direction along the axis toward the end face 801 of the battery cell 80) is larger than the heat conduction in the direction orthogonal to this direction.

According to this embodiment, the following effects are achieved.
In the present embodiment, the cell holder 82 is formed so as to surround the side surface 802 as a side end intersecting the one end surface 801 of the battery cell 80 in the circumferential direction. Then, in the cell holder 82, the cell holder 82 facing the corner portion 803 formed between the one end surface 801 and the side surface 802 of the battery cell 80 is projected toward the corner portion 803 at the portion surrounding the battery cell 80 in the circumferential direction. It has a convex portion 824 and a concave portion 825 that is recessed from the corner portion 803 side in a portion that surrounds the battery cell 80 in the circumferential direction. The convex portion 824 has a curved surface 8241 recessed from the corner portion 803 side at a position facing the corner portion 803, and the concave portion 825 has a similar portion 8251 having a similar shape to the corner portion 803 at a position facing the corner portion 803. Has.

As a result, the position where the corner portion 803 of the battery cell 80 abuts on the curved surface 8241 of the convex portion 824 can be appropriately changed according to the diameter of the battery cell 80. Therefore, regardless of whether the diameter of the battery cell 80 is large or small, the end portion of the battery cell 80 is formed by the convex portion 824 and the inner peripheral surface upper portion 828 of the wall portion 822 from the vertical direction. The battery cell 80 can be reliably held by the cell holder 82. That is, it is possible to absorb manufacturing variations in the external dimensions of the battery cell 80. As a result, the battery cell 80 can be surely brought into contact with the cell holder 82, and the battery pack 1 in which the holding of the battery cell 80 by the cell holder 82 is improved can be obtained. As a result, it is possible to improve the performance of the battery pack as a whole.

Further, in the present embodiment, the convex portion 824 is provided at a position lower than the vertical lower end of the battery cell 80, or the concave portion 825 is provided at a position higher than the vertical upper end of the battery cell 80. As a result, the gap 826 between the lower surface 8022 of the battery cell 80 and the lower inner peripheral surface 827 of the wall portion 822 of the cell holder 82 is increased so that the upper surface 8021 of the battery cell 80 and the upper inner peripheral surface 828 of the wall portion 822 of the cell holder 82 are increased. It is possible to reduce the gap between the two. As a result, it is possible to suppress heat transfer from the lower side of the battery cell 80 and promote heat transfer from the upper side of the battery cell 80.

Further, in the present embodiment, in the portion surrounding the side surface 802 of the cell holder 82, the heat conduction toward the end surface 801 which is one end side is orthogonal to the direction toward the end surface 801 (orthogonal to the axial direction of the battery cell 80). Greater than heat conduction in the direction of As a result, in the wall portion 822 of the cell holder 82 that surrounds one end and the other end of the battery cell 80, the axial end portion of the battery cell 80 is formed from the portion between the plurality of battery cells 80 arranged in a parallel positional relationship. It becomes possible to transfer heat toward. This makes it possible to effectively dissipate heat from the battery cell 80. As a result, the performance of the battery pack 1 can be improved.

Further, in the present embodiment, the portion of the cell holder 82 surrounding the side end of the battery cell 80 is made of a particle-oriented material, and more specifically, a heat transfer filler-oriented material. As a result, in the wall portion 822 of the cell holder 82 that surrounds one end and the other end of the battery cell 80, from the portion between the plurality of battery cells 80 arranged in a parallel positional relationship to the end portion in the axial direction of the battery. It becomes possible to more effectively transfer heat toward. This makes it possible to dissipate heat from the battery cell 80 more effectively.

The present invention is not limited to the above-described embodiment, and modifications, improvements, and the like within the range in which the object of the present invention can be achieved are included in the present invention.
For example, the cell holder 82 holds both ends of the battery cell 80, but the present invention is not limited to this configuration. One end of the battery cell may be held in the cell holder.
Further, in the present embodiment, the configuration of each part of the power storage device such as the power storage unit, the holding part, the convex portion, and the concave portion is composed of each part of the battery pack 1 such as the battery cell 80, the cell holder 82, the convex portion 824, and the concave portion 825. However, it is not limited to this. For example, the shapes of the convex portion and the concave portion are not limited to the shapes of the convex portion 824 and the concave portion 825 in the present embodiment.
Further, the convex portion 824 is provided at a position lower than the vertical lower end of the battery cell 80, and the concave portion 825 is provided at a position higher than the vertical upper end of the battery cell 80, but the configuration is limited to this. Not done. For example, is the convex portion provided at a position lower than the vertical lower end of the battery cell as the power storage unit, or is the concave portion provided at a position higher than the vertical upper end of the battery cell as the power storage unit? Either one may be used.

1 ... Battery pack (power storage device)
10 ... Battery case (housing)
80 ... Battery cell (storage unit, cylindrical cell)
82 ... Cell holder (holding part)
801 ... End face (one end)
802 ... Side surface (side edge)
803 ... Corner 824 ... Convex 825 ... Concave 8221 ... Filler (heat transfer filler oriented material)
8241 ... Curved surface 8251 ... Similar parts

Claims (10)

Power storage unit and
A holding unit arranged at one end of the power storage unit and holding the power storage unit is provided.
The holding portion is formed so as to surround the side end intersecting with the one end of the power storage portion in the circumferential direction.
In the holding portion, the portion of the holding portion facing the corner portion formed between the one end and the side end of the power storage portion is formed.
A convex portion that is convex on the corner side in the portion that surrounds the circumferential direction, or
A power storage device having at least one of recesses recessed from the corner side in a portion surrounded in the circumferential direction. The convex portion is provided at a position lower than the lower end in the vertical direction of the power storage unit, or
The power storage device according to claim 1, wherein the recess is provided at a position higher than the upper end of the power storage unit in the vertical direction. The power storage device according to claim 1 or 2, wherein the convex portion has a curved surface recessed from the corner portion side at a position facing the corner portion. The power storage device according to claim 2 or 3, wherein the concave portion has a similar portion having a similar shape to the corner portion at a position facing the corner portion. The portion surrounding the side end of the holding portion, according to any one of claims 1 to 4, wherein the heat conduction to the one end side is larger than the heat conduction in the direction orthogonal to the direction to the one end. The power storage device described. The power storage device according to claim 5, wherein the portion surrounding the side end of the holding portion is made of a particle-oriented material. The power storage device according to claim 6, wherein the portion surrounding the side end of the holding portion is made of a material oriented with a heat transfer filler. The power storage device according to any one of claims 1 to 7, wherein the holding parts are arranged apart from each other and have a pair of holding parts for holding one end and the other end of the power storage unit. The power storage device according to claim 8, wherein the holding unit and the power storage unit are housed in a housing. The power storage device according to claim 9, wherein the power storage unit has a cylindrical cell.

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