CN118748292A - Battery Module - Google Patents

Abstract

The present invention relates to a battery module, which is formed by stacking a plurality of battery cells. The battery cell has a flat battery body, a heat insulating portion, and a heat dissipating portion. The heat insulating portion overlaps at least a portion of the battery body in a plan view. The heat dissipating portion is provided along at least a portion of a side surface of the battery body.

Description

Battery Module

This application is a divisional application of the invention patent application with the application date of September 11, 2018, application number 201880057347.6, and invention name “Battery Cell and Battery Module”.

Technical Field

The present invention relates to storage batteries.

Background Art

Storage batteries are used in various applications. For example, storage batteries are used to drive machines such as bicycles with electric motors and small flying objects (such as drones).

As prior art related to storage batteries, there are, for example, Patent Document 1 and Patent Document 2. Patent Document 1 discloses a laminated secondary battery that suppresses stress concentration on the adhesive portion of the laminated film. Patent Document 2 discloses a battery module formed by stacking a plurality of thin-film-encased batteries placed on a frame. Patent Document 3 discloses a battery pack device that stacks single battery cells. In the battery pack device of Patent Document 3, heat conduction components for heat dissipation are respectively provided on the single battery cells facing each other. Furthermore, in order to prevent heat conduction between the single battery cells, a heat insulating layer is provided between the heat conduction components.

Prior art literature

Patent Literature

Patent Document 1: Japanese Patent Application Publication No. 2005-317312

Patent Document 2: International Publication No. 2014/196331

Patent Document 3: Japanese Patent Application Publication No. 2012-084347

Summary of the invention

Problems to be solved by the invention

Storage batteries sometimes do not function properly in low-temperature environments. For this reason, storage batteries used in low-temperature environments require thermal insulation to prevent the influence of the low-temperature external atmosphere. On the other hand, it is also required that the heat generated inside the storage battery be dissipated to the outside. The inventors of the present invention have developed a new storage battery that can be used in low-temperature environments.

The present invention has been made in view of the above-mentioned problems, and one object of the present invention is to provide a new storage battery that can be used in a low-temperature environment.

Means for solving problems

The battery cell of the present invention comprises: 1) a flat battery body; 2) a heat insulating portion overlapping at least a portion of the battery body in a plan view; and 3) a heat dissipating portion provided along at least a portion of a side surface of the battery body.

The battery module of the present invention is formed by stacking multiple battery cells of the present invention, and the battery cell has: a flat battery body; an insulating portion overlapping with at least a portion of the battery body when viewed from above; and a heat dissipation portion provided on at least a portion of a side surface of the battery body, the battery cell has a seal that seals the battery body, the insulating portion is provided via an adhesive on the portion of the seal where the battery body exists when viewed from above, and the multiple battery cells are stacked via an adhesive on the surfaces of adjacent battery cells where the insulating portions are provided that are respectively opposite to each other.

Effects of the Invention

According to the present invention, a new storage battery that can be used in a low-temperature environment is provided.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned objects and other objects, features and advantages will become more apparent from the preferred embodiments described below and the following drawings attached thereto.

FIG. 1 is a perspective view showing an example of a battery cell according to the first embodiment.

FIG. 2 is a diagram illustrating a battery cell housed in a housing.

FIG. 3 is a diagram illustrating a case where a heat insulating portion is provided on both the upper surface side and the lower surface side of a battery cell.

FIG. 4 is a diagram illustrating deformation of sealing of a sealing member.

FIG. 5 is a diagram illustrating an example of a heat insulating portion provided so as to overlap with the battery body and not overlap with the peripheral portion of the seal.

FIG. 6 is a diagram illustrating a bag-shaped sealing member.

FIG. 7 is a perspective view illustrating a battery module according to the second embodiment.

FIG. 8 is a YZ plan view of the battery module according to the second embodiment.

FIG. 9 is a diagram illustrating a case where a heat insulating portion is provided on the upper surface of each battery cell.

FIG. 10 is a perspective view of a battery module composed of battery cells stacked in a frame.

FIG. 11 is a cross-sectional view taken along line AB of battery cells stacked using a frame.

FIG. 12 is a diagram illustrating a battery module housed in a casing.

FIG. 13 is a diagram illustrating a battery module housed in a case in a state where a portion of a peripheral portion is bent downward.

DETAILED DESCRIPTION

The following drawings are used to illustrate the embodiments of the present invention. In addition, the same reference numerals are used for the same components in all drawings, and the description is omitted as appropriate. In addition, except for the case where it is specially explained, each block in the block diagram is not a structure of a hardware unit, but a structure of a functional unit.

FIG1 is a perspective view showing an example of a battery cell according to Embodiment 1. The battery cell 100 has a flat battery body 110 inside. For example, the shape of the battery body 110 is a rectangular parallelepiped. However, the shape of the battery body 110 does not need to be a strict rectangular parallelepiped, and for example, the shape of the rectangular parallelepiped with chamfered edges and vertices may be used.

In addition, the shape of the battery body 110 is flat, that is, the length of the side of the surface of the battery body 110 viewed from the top and bottom (the surface of the battery body 110 viewed from the XY direction in FIG. 1) is greater than the thickness of the battery body 110 (the size in the Z direction in FIG. 1), and is not limited to a rectangular parallelepiped. The shape of the surface of the battery body 110 viewed from the top and bottom can be any shape (for example, an ellipse, etc.). In addition, the size of the top and bottom surfaces of the battery body 110 may also be different.

The battery cell 100 is a single cell of a secondary battery such as a lithium-ion battery, and has a structure in which the battery body 110 is sealed by a sealant 140. The sealant 140 is a member that seals the battery body 110. For example, the sealant 140 is a laminated film. In this case, the battery body 110 is laminated and sealed by the sealant 140. For example, the battery body 110 is sealed between two films constituting the sealant 140. And the film extends over the entire circumference of the battery body 110 and protrudes further outward than the battery body 110. The portion that protrudes further outward than the battery body 110 is hereinafter referred to as the peripheral portion of the sealant 140 (reference numeral 142). In other words, the peripheral portion 142 is a portion of the sealant 140 that is located on the periphery of the side of the battery body 110. In addition, the peripheral portion 142 is a portion where the two films constituting the sealant 140 are opposed to each other without separating the battery body 110.

The battery cell 100 further includes a heat insulating portion 120 , a heat dissipating portion, and an electrode 160 . The heat insulating portion 120 is formed of a member having a lower thermal conductivity than at least the sealing member 140 .

It is preferred that the heat insulating part 120 is a member having a plurality of gaps therein. The plurality of gaps may be independent of each other. In addition, at least two gaps may be connected to each other. The heat insulating part 120 having a plurality of gaps therein is formed of a porous material such as nitrile-based synthetic rubber. However, the heat insulating part 120 may also be formed of a material other than a porous material (e.g., polyurethane).

It is more preferable that the thermal conductivity of the heat insulating portion 120 is set to be 0.02 W/mK or more. It is more preferable that the thermal conductivity of the heat insulating portion 120 is set to be 0.05 W/mK or less.

The heat insulating portion 120 is provided to overlap at least a portion of the battery body 110 in XY plan view. From the viewpoint of heat insulation, the heat insulating portion 120 preferably has substantially the same area as the battery body 110 in XY plan view and is provided to overlap substantially the entire area of the battery body 110.

It is preferred that the thickness of the heat insulating portion 120 is set to be 2 mm or more. In addition, it is preferred that the thickness of the heat insulating portion 120 is set to be 3 mm or less. In addition, the thickness of the heat insulating portion 120 may be uniform or non-uniform. For example, in a case where the temperature distribution within the battery cell 100 becomes non-uniform when the battery cell 100 is in use, it is preferred that the thickness of the heat insulating portion 120 be non-uniform in accordance with the temperature distribution. Specifically, the thickness of the region of the heat insulating portion 120 that overlaps with the region within the battery cell 100 with a relatively high temperature when viewed from above is made relatively thin. On the other hand, the thickness of the region of the heat insulating portion 120 that overlaps with the region within the battery cell 100 with a relatively low temperature is made relatively thick.

For example, the thickness of the center portion of the heat insulating portion 120 is made thinner than other portions when viewed from above. This is because, when the peripheral portion 142 functions as a heat dissipation portion as described later, the temperature of the portion close to the peripheral portion 142 (the portion far from the center portion of the heat insulating portion 120) in the battery cell 100 is more likely to be lower than that of the portion far from the peripheral portion 142 (the portion close to the center portion of the heat insulating portion 120) due to the heat dissipation effect of the peripheral portion 142. In addition, for example, the temperature distribution in the battery cell 100 may be preliminarily understood by testing the battery cell 100 before use, and the thickness distribution of the heat insulating portion 120 may be determined based on the temperature distribution.

The planar shape of the heat insulating portion 120 is not limited to the rectangular shape shown in Fig. 1 , and may be any shape. In addition, the heat insulating portion 120 may have a plurality of openings in a plan view.

The heat insulating part 120 may be directly mounted on the seal 140 or mounted on the seal 140 via other components. In the former case, for example, the heat insulating part 120 is welded to the seal 140. In the latter case, for example, the heat insulating part 120 is mounted on the seal 140 using an adhesive material such as a double-sided tape.

The heat dissipation part is a member that has the function of dissipating the heat generated from the battery body 110 to the outside of the battery cell 100. For example, the heat dissipation part is formed of air, metal, etc. It is preferred that the thermal conductivity of the heat dissipation part is set to 0.4 W/mK or more. In addition, it is preferred that the thermal conductivity of the heat dissipation part is set to 0.6 W/mK or less. In particular, it is preferred that the thermal conductivity of the heat dissipation part is set to 0.5 W/mK.

The heat dissipation portion is provided along at least a portion of the side surface of the battery body 110. For example, the heat dissipation portion is provided over the entire circumference of the side surface of the battery body 110.

In FIG1 , the heat dissipation part is constituted by a seal 140. Specifically, the seal 140 has a peripheral portion 142 located at the periphery of the side surface of the battery body 110, and the peripheral portion 142 functions as a heat dissipation part. In addition, the heat dissipation part may be a part of the peripheral portion 142 or the whole. It is preferred that the peripheral portion 142 functioning as a heat dissipation part has an area of 20% or more of the entire area of the battery cell 100 in the YX plan view.

When the seal 140 is composed of a laminated film and the peripheral portion 142 functions as a heat dissipation portion, it is preferred that the laminated film contains a metal material (e.g., aluminum). For example, the laminated film has a laminated structure of a resin layer for thermal compression bonding and a metal layer for heat dissipation. It is preferred that the thickness of the metal layer is set to be 20% or more of the entire laminated film. In addition, it is preferred that the thickness of the metal layer is set to be 50% or less of the entire laminated film.

The heat dissipation part may be formed by a structure other than the peripheral part 142 of the seal 140. For example, the battery cell 100 may be housed in a frame, and a part of the frame may function as the heat dissipation part. The frame is preferably formed of a member having high thermal conductivity, such as resin.

FIG. 2 is a diagram illustrating a battery cell 100 housed in a frame. In FIG. 2 , the frame 10 is formed to hold the electrode 160. In addition, the frame 10 is formed to hold the peripheral portion 142 over the entire circumference. However, the frame 10 does not necessarily have to hold the peripheral portion 142 over the entire circumference, and may be formed to hold only a portion of the peripheral portion 142. The frame 10 is preferably lightweight. Specifically, a weight per unit volume of about 1 g is preferred.

In the description so far, the structure in which the battery body is sealed with a seal (battery cell 100 in FIG. 2 ) is referred to as a battery cell, but the structure in which the battery body is sealed with a seal and the frame that accommodates the structure (battery cell 100 and frame 10 in FIG. 2 ) may be collectively referred to as a battery cell. For the sake of convenience, the structure in which the battery body is sealed with a seal without a frame is referred to as a battery cell as in the description so far.

The electrode 160 is an electrode connected to the battery body 110 and is led out to the outside of the seal 140. In FIG. 1 , two electrodes 160 are arranged side by side on one short side of the battery cell 100 in an XY top view. However, the position of the electrode 160 is arbitrary. For example, two electrodes 160 may be arranged side by side on one long side of the battery cell 100, one electrode 160 may be arranged on each of the two opposing short sides, or one electrode 160 may be arranged on each of the two opposing long sides.

<Function and Effect>

In the battery cell 100 of this embodiment, the heat insulating portion 120 is provided at a position overlapping at least a portion of the battery body 110 in a plan view. The heat insulating portion 120 can reduce the influence of the low temperature external atmosphere on the battery body 110. Therefore, the low temperature characteristics of the battery cell 100 can be improved.

In the battery cell 100 of this embodiment, a heat dissipation portion is provided along at least a portion of the side surface of the battery body 110. Since the heat generated by the battery body 110 is released to the outside through the heat dissipation portion, the battery body 110 can be prevented from becoming hot.

Furthermore, in the battery cell 100, the heat insulating portion 120 and the heat dissipating portion are provided at separate positions. In this way, it is possible to prevent the heat insulating portion 120 and the heat dissipating portion from interfering with each other and thus reducing the efficiency of heat insulation or heat dissipation.

<Other modifications of battery cell 100>

1 is provided on the upper surface side (−Z side) of the battery cell 100 . However, the heat insulating portion 120 may be provided on the lower surface side (+Z side) of the battery cell 100 , or may be provided on both the upper surface side and the lower surface side of the battery cell 100 .

FIG3 is a diagram illustrating a case where the heat insulating portion 120 is provided on both the upper surface side and the lower surface side of the battery cell 100. The heat insulating portion 120 provided on the upper surface side and the heat insulating portion 120 provided on the lower surface side may be of the same size or of different sizes. In addition, these heat insulating portions 120 may be arranged so that at least a portion overlaps when viewed from above, or may be arranged so that they do not overlap when viewed from above.

In Fig. 1, the sealant 140 seals the battery body 110 so that the portion protruding more than the electrode 160 in a YZ plan view exists on both the upper surface side and the lower surface side of the battery body 110. However, the sealant 140 may seal the battery body 110 so that the portion protruding more than the electrode 160 in a YZ plan view exists only on one of the upper surface side and the lower surface side of the battery body 110.

Fig. 4 is a diagram illustrating deformation of the seal of the seal 140. In Fig. 4(a), the portion protruding from the electrode 160 in the YZ plan view exists only on the upper surface side of the battery body 110. On the other hand, in Fig. 4(b), the portion protruding from the electrode 160 in the YZ plan view exists only on the lower surface side of the battery body 110.

In the case where the portion that protrudes more than the electrode 160 in a YZ top view exists only on the upper surface side or one of the lower surface sides of the battery body 110 as shown in FIG4 , the heat insulating portion 120 may be provided on either the upper surface side or the lower surface side of the battery body 110 , or on both.

Here, the heat insulating portion 120 is provided on the side that does not protrude more than the electrode 160 in a YZ top view. FIG5 is a diagram illustrating a case where the heat insulating portion 120 is provided on the side that does not protrude more than the electrode 160 in a YZ top view. In this case, the heat insulating portion 120 can also be provided at a position overlapping with the peripheral portion 142 in a top view. However, since both heat insulation and heat dissipation are taken into account, it is preferred that the heat insulating portion 120 is provided to overlap with the battery body 110 and not overlap with the peripheral portion of the seal 140 (refer to FIG5). In addition, from the viewpoint of heat insulation, it is preferred that the heat insulating portion 120 is provided to overlap with substantially the entire area of the battery body 110.

The seal 140 is not limited to being composed of two films as described above. For example, the seal 140 may be composed of a bag-shaped film. FIG. 6 is a diagram illustrating a bag-shaped seal 140. Before the battery cell 100 is inserted into the seal 140, only one of the four sides is open. Then, by inserting the battery cell 100 from the open portion, the open portion is sealed (e.g., laminated sealing), thereby forming a battery cell 100 in which the battery cell 100 is sealed.

[Implementation Method 2]

7 is a perspective view illustrating a battery module 200 according to Embodiment 2. The battery module 200 is a battery pack formed by stacking a plurality of battery cells 100 .

FIG8 is a YZ top view of a battery module 200 according to Embodiment 2. In each battery cell 100 of FIG8 , a heat insulating portion 120 is provided on both the upper surface side and the lower surface side, similarly to the battery cell 100 shown in FIG3 . Furthermore, in FIG8 , two adjacent battery cells 100 are stacked with an adhesive 150 (hereinafter referred to as an adhesive) interposed therebetween. The adhesive is, for example, a double-sided tape.

As described in Embodiment 1, the heat insulating portion 120 may be provided only on either the upper surface side or the lower surface side of the battery cell 100. In the case where the heat insulating portion 120 is provided only on either the upper surface side or the lower surface side of the battery cell 100, it is preferred that a plurality of battery cells 100 have the heat insulating portion 120 on the same side. FIG. 9 is a diagram illustrating a case where a heat insulating portion 120 is provided on the upper surface of each battery cell 100. The battery cell 100 of FIG. 9 differs from the battery cell 100 shown in FIG. 3 in that the heat insulating portion 120 is provided only on the upper side. By providing the heat insulating portion 120 on the same side of each battery cell 100 in this manner, the heat insulating portion 120 is necessarily located between two adjacent battery cells 100. Therefore, heat conduction between two adjacent battery cells 100 can be prevented.

Here, the method of maintaining the state in which a plurality of battery cells 100 are stacked is not limited to the method of fixing the battery cells 100 to each other using the adhesive 150. For example, in the case where adjacent battery cells 100 have heat insulating portions 120 on surfaces facing each other, the surfaces of the heat insulating portions 120 facing each other may be engaged. In this case, the surfaces of the heat insulating portions 120 are processed so that the surfaces of the heat insulating portions 120 facing each other are engaged. For example, a concave-convex shape is provided on the heat insulating portion 120, and the convex portion of the heat insulating portion 120 on one side is processed so as to be embedded in the concave portion of the heat insulating portion 120 on the other side. In addition, various other processes can be used in the process of engaging the surfaces with each other. For example, the state of stacking the battery cells 100 can be maintained by bundling the plurality of battery cells 100 constituting the battery module 200 with a belt or the like.

The battery cells 100 can be stacked using the frame 10. Fig. 10 is a perspective view of a battery module 200 including the battery cells 100 stacked using the frame 10. Fig. 11 is a cross-sectional view taken along the line AB in Fig. 10 .

When the frame 10 is used, for example, by engaging a portion of one frame 10 with a portion of the other frame 10 of two adjacent frames 10 (for example, a portion of one frame 10 holds a portion of the other frame 10), the stacked state of the plurality of frames 10 can be maintained. In addition, for example, the stacked state of the frames 10 can be maintained by providing an adhesive 150 between two adjacent frames 10. In addition, the stacked state of the frames 10 can be maintained by binding the battery modules 200 with a band or the like.

The battery module 200 can be housed in a housing. FIG. 12 is a diagram illustrating a battery module 200 housed in a housing. The battery module 200 housed in the housing 20 in FIG. 12 is the battery module illustrated in FIG. 8 . From the perspective of heat dissipation, it is preferred to provide holes in the housing 20 for air to pass through. It is preferred to provide as many holes as possible evenly on each surface of the housing 20.

When housed in the housing 20, a portion of the peripheral portion 142 of the seal 140 may be bent. FIG13 is a diagram illustrating a battery module 200 housed in the housing 20 in a state where a portion of the peripheral portion 142 is bent. The battery module 200 housed in the housing 20 in FIG13 is the battery module illustrated in FIG8 . In this way, the size of the housing 20 (the size of the battery module 200) can be reduced.

Although the embodiments of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various configurations other than those described above can be employed.

This application claims the benefit of priority based on Japanese patent application No. 2017-182241, filed on September 22, 2017, the disclosure of which is incorporated herein in its entirety.

Claims (9)

1.A battery module, characterized in that,

The battery module is formed by stacking a plurality of battery cells,

The battery cell has:

A flat battery body;

A heat insulating portion overlapping at least a part of the battery main body in a plan view; and

A heat dissipation part provided on at least a part of a side surface of the battery main body,

The battery cell has a seal member that seals the battery body,

The heat insulating part is provided via an adhesive to the seal member at a portion where the battery main body exists in a plan view,

The plurality of battery cells are laminated via an adhesive material on surfaces of the adjacent battery cells on which the heat insulation portions are provided, the surfaces facing each other.

2. The battery module of claim 1, wherein the battery module comprises a plurality of cells,

The seal member has a peripheral portion located at the periphery of the side face of the battery main body,

The heat sink is at least a portion of the peripheral portion of the seal.

3. The battery module of claim 1, wherein the battery module comprises a plurality of cells,

The battery cell has a frame body, and the battery cell has a plurality of battery cells,

The seal member has a peripheral portion located at the periphery of the side face of the battery main body,

The frame body holds the peripheral portion,

The heat dissipation portion is the frame.

4. The battery module according to any one of claims 1 to 3, wherein,

The thickness of the central portion of the heat insulating portion of the battery cell is thinner than the thickness of a portion other than the central portion of the heat insulating portion of the battery cell.

5. The battery module according to any one of claims 1 to 3, wherein,

The heat dissipation portion of the battery cell has a thermal conductivity of 0.4W/mK or more and 0.6W/mK or less.

6. The battery module according to any one of claims 1 to 3, wherein,

The thermal conductivity of the heat insulation part of the battery cell is 0.02W/mK or more and 0.05W/mK or less.

7. The battery module according to any one of claims 1 to 3, wherein,

The heat insulation part of the battery cell has a plurality of voids.

8. The battery module according to any one of claims 1 to 3, wherein,

The heat insulating part of the battery cell is provided on both the upper surface side and the lower surface side of the battery body.

9. The battery module according to any one of claims 1 to 3, wherein,

The seal of the battery cell seals the battery body such that there are protruding portions on both the upper surface side and the lower surface side of the battery body.